drivers/spi/spi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 // SPI init/core code
   3 //
   4 // Copyright (C) 2005 David Brownell
   5 // Copyright (C) 2008 Secret Lab Technologies Ltd.
   6
   7 #include <linux/kernel.h>
   8 #include <linux/device.h>
   9 #include <linux/init.h>
  10 #include <linux/cache.h>
  11 #include <linux/dma-mapping.h>
  12 #include <linux/dmaengine.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of_device.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/clk/clk-conf.h>
  17 #include <linux/slab.h>
  18 #include <linux/mod_devicetable.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/spi/spi-mem.h>
  21 #include <linux/gpio/consumer.h>
  22 #include <linux/pm_runtime.h>
  23 #include <linux/pm_domain.h>
  24 #include <linux/property.h>
  25 #include <linux/export.h>
  26 #include <linux/sched/rt.h>
  27 #include <uapi/linux/sched/types.h>
  28 #include <linux/delay.h>
  29 #include <linux/kthread.h>
  30 #include <linux/ioport.h>
  31 #include <linux/acpi.h>
  32 #include <linux/highmem.h>
  33 #include <linux/idr.h>
  34 #include <linux/platform_data/x86/apple.h>
  35 #include <linux/ptp_clock_kernel.h>
  36 #include <linux/percpu.h>
  37
  38 #define CREATE_TRACE_POINTS
  39 #include <trace/events/spi.h>
  40 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_start);
  41 EXPORT_TRACEPOINT_SYMBOL(spi_transfer_stop);
  42
  43 #include "internals.h"
  44
  45 static DEFINE_IDR(spi_master_idr);
  46
  47 static void spidev_release(struct device *dev)
  48 {
  49         struct spi_device       *spi = to_spi_device(dev);
  50
  51         spi_controller_put(spi->controller);
  52         kfree(spi->driver_override);
  53         free_percpu(spi->pcpu_statistics);
  54         kfree(spi);
  55 }
  56
  57 static ssize_t
  58 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  59 {
  60         const struct spi_device *spi = to_spi_device(dev);
  61         int len;
  62
  63         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  64         if (len != -ENODEV)
  65                 return len;
  66
  67         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  68 }
  69 static DEVICE_ATTR_RO(modalias);
  70
  71 static ssize_t driver_override_store(struct device *dev,
  72                                      struct device_attribute *a,
  73                                      const char *buf, size_t count)
  74 {
  75         struct spi_device *spi = to_spi_device(dev);
  76         int ret;
  77
  78         ret = driver_set_override(dev, &spi->driver_override, buf, count);
  79         if (ret)
  80                 return ret;
  81
  82         return count;
  83 }
  84
  85 static ssize_t driver_override_show(struct device *dev,
  86                                     struct device_attribute *a, char *buf)
  87 {
  88         const struct spi_device *spi = to_spi_device(dev);
  89         ssize_t len;
  90
  91         device_lock(dev);
  92         len = snprintf(buf, PAGE_SIZE, "%s\n", spi->driver_override ? : "");
  93         device_unlock(dev);
  94         return len;
  95 }
  96 static DEVICE_ATTR_RW(driver_override);
  97
  98 static struct spi_statistics __percpu *spi_alloc_pcpu_stats(struct device *dev)
  99 {
 100         struct spi_statistics __percpu *pcpu_stats;
 101
 102         if (dev)
 103                 pcpu_stats = devm_alloc_percpu(dev, struct spi_statistics);
 104         else
 105                 pcpu_stats = alloc_percpu_gfp(struct spi_statistics, GFP_KERNEL);
 106
 107         if (pcpu_stats) {
 108                 int cpu;
 109
 110                 for_each_possible_cpu(cpu) {
 111                         struct spi_statistics *stat;
 112
 113                         stat = per_cpu_ptr(pcpu_stats, cpu);
 114                         u64_stats_init(&stat->syncp);
 115                 }
 116         }
 117         return pcpu_stats;
 118 }
 119
 120 #define spi_pcpu_stats_totalize(ret, in, field)                         \
 121 do {                                                                    \
 122         int i;                                                          \
 123         ret = 0;                                                        \
 124         for_each_possible_cpu(i) {                                      \
 125                 const struct spi_statistics *pcpu_stats;                \
 126                 u64 inc;                                                \
 127                 unsigned int start;                                     \
 128                 pcpu_stats = per_cpu_ptr(in, i);                        \
 129                 do {                                                    \
 130                         start = u64_stats_fetch_begin_irq(              \
 131                                         &pcpu_stats->syncp);            \
 132                         inc = u64_stats_read(&pcpu_stats->field);       \
 133                 } while (u64_stats_fetch_retry_irq(                     \
 134                                         &pcpu_stats->syncp, start));    \
 135                 ret += inc;                                             \
 136         }                                                               \
 137 } while (0)
 138
 139 #define SPI_STATISTICS_ATTRS(field, file)                               \
 140 static ssize_t spi_controller_##field##_show(struct device *dev,        \
 141                                              struct device_attribute *attr, \
 142                                              char *buf)                 \
 143 {                                                                       \
 144         struct spi_controller *ctlr = container_of(dev,                 \
 145                                          struct spi_controller, dev);   \
 146         return spi_statistics_##field##_show(ctlr->pcpu_statistics, buf); \
 147 }                                                                       \
 148 static struct device_attribute dev_attr_spi_controller_##field = {      \
 149         .attr = { .name = file, .mode = 0444 },                         \
 150         .show = spi_controller_##field##_show,                          \
 151 };                                                                      \
 152 static ssize_t spi_device_##field##_show(struct device *dev,            \
 153                                          struct device_attribute *attr, \
 154                                         char *buf)                      \
 155 {                                                                       \
 156         struct spi_device *spi = to_spi_device(dev);                    \
 157         return spi_statistics_##field##_show(spi->pcpu_statistics, buf); \
 158 }                                                                       \
 159 static struct device_attribute dev_attr_spi_device_##field = {          \
 160         .attr = { .name = file, .mode = 0444 },                         \
 161         .show = spi_device_##field##_show,                              \
 162 }
 163
 164 #define SPI_STATISTICS_SHOW_NAME(name, file, field)                     \
 165 static ssize_t spi_statistics_##name##_show(struct spi_statistics __percpu *stat, \
 166                                             char *buf)                  \
 167 {                                                                       \
 168         ssize_t len;                                                    \
 169         u64 val;                                                        \
 170         spi_pcpu_stats_totalize(val, stat, field);                      \
 171         len = sysfs_emit(buf, "%llu\n", val);                           \
 172         return len;                                                     \
 173 }                                                                       \
 174 SPI_STATISTICS_ATTRS(name, file)
 175
 176 #define SPI_STATISTICS_SHOW(field)                                      \
 177         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 178                                  field)
 179
 180 SPI_STATISTICS_SHOW(messages);
 181 SPI_STATISTICS_SHOW(transfers);
 182 SPI_STATISTICS_SHOW(errors);
 183 SPI_STATISTICS_SHOW(timedout);
 184
 185 SPI_STATISTICS_SHOW(spi_sync);
 186 SPI_STATISTICS_SHOW(spi_sync_immediate);
 187 SPI_STATISTICS_SHOW(spi_async);
 188
 189 SPI_STATISTICS_SHOW(bytes);
 190 SPI_STATISTICS_SHOW(bytes_rx);
 191 SPI_STATISTICS_SHOW(bytes_tx);
 192
 193 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 194         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 195                                  "transfer_bytes_histo_" number,        \
 196                                  transfer_bytes_histo[index])
 197 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 198 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 199 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 200 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 201 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 202 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 203 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 204 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 205 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 206 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 207 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 208 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 209 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 210 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 211 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 212 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 213 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 214
 215 SPI_STATISTICS_SHOW(transfers_split_maxsize);
 216
 217 static struct attribute *spi_dev_attrs[] = {
 218         &dev_attr_modalias.attr,
 219         &dev_attr_driver_override.attr,
 220         NULL,
 221 };
 222
 223 static const struct attribute_group spi_dev_group = {
 224         .attrs  = spi_dev_attrs,
 225 };
 226
 227 static struct attribute *spi_device_statistics_attrs[] = {
 228         &dev_attr_spi_device_messages.attr,
 229         &dev_attr_spi_device_transfers.attr,
 230         &dev_attr_spi_device_errors.attr,
 231         &dev_attr_spi_device_timedout.attr,
 232         &dev_attr_spi_device_spi_sync.attr,
 233         &dev_attr_spi_device_spi_sync_immediate.attr,
 234         &dev_attr_spi_device_spi_async.attr,
 235         &dev_attr_spi_device_bytes.attr,
 236         &dev_attr_spi_device_bytes_rx.attr,
 237         &dev_attr_spi_device_bytes_tx.attr,
 238         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 239         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 240         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 241         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 242         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 243         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 244         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 245         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 246         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 247         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 248         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 249         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 250         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 251         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 252         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 253         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 254         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 255         &dev_attr_spi_device_transfers_split_maxsize.attr,
 256         NULL,
 257 };
 258
 259 static const struct attribute_group spi_device_statistics_group = {
 260         .name  = "statistics",
 261         .attrs  = spi_device_statistics_attrs,
 262 };
 263
 264 static const struct attribute_group *spi_dev_groups[] = {
 265         &spi_dev_group,
 266         &spi_device_statistics_group,
 267         NULL,
 268 };
 269
 270 static struct attribute *spi_controller_statistics_attrs[] = {
 271         &dev_attr_spi_controller_messages.attr,
 272         &dev_attr_spi_controller_transfers.attr,
 273         &dev_attr_spi_controller_errors.attr,
 274         &dev_attr_spi_controller_timedout.attr,
 275         &dev_attr_spi_controller_spi_sync.attr,
 276         &dev_attr_spi_controller_spi_sync_immediate.attr,
 277         &dev_attr_spi_controller_spi_async.attr,
 278         &dev_attr_spi_controller_bytes.attr,
 279         &dev_attr_spi_controller_bytes_rx.attr,
 280         &dev_attr_spi_controller_bytes_tx.attr,
 281         &dev_attr_spi_controller_transfer_bytes_histo0.attr,
 282         &dev_attr_spi_controller_transfer_bytes_histo1.attr,
 283         &dev_attr_spi_controller_transfer_bytes_histo2.attr,
 284         &dev_attr_spi_controller_transfer_bytes_histo3.attr,
 285         &dev_attr_spi_controller_transfer_bytes_histo4.attr,
 286         &dev_attr_spi_controller_transfer_bytes_histo5.attr,
 287         &dev_attr_spi_controller_transfer_bytes_histo6.attr,
 288         &dev_attr_spi_controller_transfer_bytes_histo7.attr,
 289         &dev_attr_spi_controller_transfer_bytes_histo8.attr,
 290         &dev_attr_spi_controller_transfer_bytes_histo9.attr,
 291         &dev_attr_spi_controller_transfer_bytes_histo10.attr,
 292         &dev_attr_spi_controller_transfer_bytes_histo11.attr,
 293         &dev_attr_spi_controller_transfer_bytes_histo12.attr,
 294         &dev_attr_spi_controller_transfer_bytes_histo13.attr,
 295         &dev_attr_spi_controller_transfer_bytes_histo14.attr,
 296         &dev_attr_spi_controller_transfer_bytes_histo15.attr,
 297         &dev_attr_spi_controller_transfer_bytes_histo16.attr,
 298         &dev_attr_spi_controller_transfers_split_maxsize.attr,
 299         NULL,
 300 };
 301
 302 static const struct attribute_group spi_controller_statistics_group = {
 303         .name  = "statistics",
 304         .attrs  = spi_controller_statistics_attrs,
 305 };
 306
 307 static const struct attribute_group *spi_master_groups[] = {
 308         &spi_controller_statistics_group,
 309         NULL,
 310 };
 311
 312 static void spi_statistics_add_transfer_stats(struct spi_statistics __percpu *pcpu_stats,
 313                                               struct spi_transfer *xfer,
 314                                               struct spi_controller *ctlr)
 315 {
 316         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 317         struct spi_statistics *stats;
 318
 319         if (l2len < 0)
 320                 l2len = 0;
 321
 322         get_cpu();
 323         stats = this_cpu_ptr(pcpu_stats);
 324         u64_stats_update_begin(&stats->syncp);
 325
 326         u64_stats_inc(&stats->transfers);
 327         u64_stats_inc(&stats->transfer_bytes_histo[l2len]);
 328
 329         u64_stats_add(&stats->bytes, xfer->len);
 330         if ((xfer->tx_buf) &&
 331             (xfer->tx_buf != ctlr->dummy_tx))
 332                 u64_stats_add(&stats->bytes_tx, xfer->len);
 333         if ((xfer->rx_buf) &&
 334             (xfer->rx_buf != ctlr->dummy_rx))
 335                 u64_stats_add(&stats->bytes_rx, xfer->len);
 336
 337         u64_stats_update_end(&stats->syncp);
 338         put_cpu();
 339 }
 340
 341 /*
 342  * modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 343  * and the sysfs version makes coldplug work too.
 344  */
 345 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id, const char *name)
 346 {
 347         while (id->name[0]) {
 348                 if (!strcmp(name, id->name))
 349                         return id;
 350                 id++;
 351         }
 352         return NULL;
 353 }
 354
 355 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 356 {
 357         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 358
 359         return spi_match_id(sdrv->id_table, sdev->modalias);
 360 }
 361 EXPORT_SYMBOL_GPL(spi_get_device_id);
 362
 363 static int spi_match_device(struct device *dev, struct device_driver *drv)
 364 {
 365         const struct spi_device *spi = to_spi_device(dev);
 366         const struct spi_driver *sdrv = to_spi_driver(drv);
 367
 368         /* Check override first, and if set, only use the named driver */
 369         if (spi->driver_override)
 370                 return strcmp(spi->driver_override, drv->name) == 0;
 371
 372         /* Attempt an OF style match */
 373         if (of_driver_match_device(dev, drv))
 374                 return 1;
 375
 376         /* Then try ACPI */
 377         if (acpi_driver_match_device(dev, drv))
 378                 return 1;
 379
 380         if (sdrv->id_table)
 381                 return !!spi_match_id(sdrv->id_table, spi->modalias);
 382
 383         return strcmp(spi->modalias, drv->name) == 0;
 384 }
 385
 386 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 387 {
 388         const struct spi_device         *spi = to_spi_device(dev);
 389         int rc;
 390
 391         rc = acpi_device_uevent_modalias(dev, env);
 392         if (rc != -ENODEV)
 393                 return rc;
 394
 395         return add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 396 }
 397
 398 static int spi_probe(struct device *dev)
 399 {
 400         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 401         struct spi_device               *spi = to_spi_device(dev);
 402         int ret;
 403
 404         ret = of_clk_set_defaults(dev->of_node, false);
 405         if (ret)
 406                 return ret;
 407
 408         if (dev->of_node) {
 409                 spi->irq = of_irq_get(dev->of_node, 0);
 410                 if (spi->irq == -EPROBE_DEFER)
 411                         return -EPROBE_DEFER;
 412                 if (spi->irq < 0)
 413                         spi->irq = 0;
 414         }
 415
 416         ret = dev_pm_domain_attach(dev, true);
 417         if (ret)
 418                 return ret;
 419
 420         if (sdrv->probe) {
 421                 ret = sdrv->probe(spi);
 422                 if (ret)
 423                         dev_pm_domain_detach(dev, true);
 424         }
 425
 426         return ret;
 427 }
 428
 429 static void spi_remove(struct device *dev)
 430 {
 431         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 432
 433         if (sdrv->remove)
 434                 sdrv->remove(to_spi_device(dev));
 435
 436         dev_pm_domain_detach(dev, true);
 437 }
 438
 439 static void spi_shutdown(struct device *dev)
 440 {
 441         if (dev->driver) {
 442                 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
 443
 444                 if (sdrv->shutdown)
 445                         sdrv->shutdown(to_spi_device(dev));
 446         }
 447 }
 448
 449 struct bus_type spi_bus_type = {
 450         .name           = "spi",
 451         .dev_groups     = spi_dev_groups,
 452         .match          = spi_match_device,
 453         .uevent         = spi_uevent,
 454         .probe          = spi_probe,
 455         .remove         = spi_remove,
 456         .shutdown       = spi_shutdown,
 457 };
 458 EXPORT_SYMBOL_GPL(spi_bus_type);
 459
 460 /**
 461  * __spi_register_driver - register a SPI driver
 462  * @owner: owner module of the driver to register
 463  * @sdrv: the driver to register
 464  * Context: can sleep
 465  *
 466  * Return: zero on success, else a negative error code.
 467  */
 468 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 469 {
 470         sdrv->driver.owner = owner;
 471         sdrv->driver.bus = &spi_bus_type;
 472
 473         /*
 474          * For Really Good Reasons we use spi: modaliases not of:
 475          * modaliases for DT so module autoloading won't work if we
 476          * don't have a spi_device_id as well as a compatible string.
 477          */
 478         if (sdrv->driver.of_match_table) {
 479                 const struct of_device_id *of_id;
 480
 481                 for (of_id = sdrv->driver.of_match_table; of_id->compatible[0];
 482                      of_id++) {
 483                         const char *of_name;
 484
 485                         /* Strip off any vendor prefix */
 486                         of_name = strnchr(of_id->compatible,
 487                                           sizeof(of_id->compatible), ',');
 488                         if (of_name)
 489                                 of_name++;
 490                         else
 491                                 of_name = of_id->compatible;
 492
 493                         if (sdrv->id_table) {
 494                                 const struct spi_device_id *spi_id;
 495
 496                                 spi_id = spi_match_id(sdrv->id_table, of_name);
 497                                 if (spi_id)
 498                                         continue;
 499                         } else {
 500                                 if (strcmp(sdrv->driver.name, of_name) == 0)
 501                                         continue;
 502                         }
 503
 504                         pr_warn("SPI driver %s has no spi_device_id for %s\n",
 505                                 sdrv->driver.name, of_id->compatible);
 506                 }
 507         }
 508
 509         return driver_register(&sdrv->driver);
 510 }
 511 EXPORT_SYMBOL_GPL(__spi_register_driver);
 512
 513 /*-------------------------------------------------------------------------*/
 514
 515 /*
 516  * SPI devices should normally not be created by SPI device drivers; that
 517  * would make them board-specific.  Similarly with SPI controller drivers.
 518  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 519  * with other readonly (flashable) information about mainboard devices.
 520  */
 521
 522 struct boardinfo {
 523         struct list_head        list;
 524         struct spi_board_info   board_info;
 525 };
 526
 527 static LIST_HEAD(board_list);
 528 static LIST_HEAD(spi_controller_list);
 529
 530 /*
 531  * Used to protect add/del operation for board_info list and
 532  * spi_controller list, and their matching process also used
 533  * to protect object of type struct idr.
 534  */
 535 static DEFINE_MUTEX(board_lock);
 536
 537 /**
 538  * spi_alloc_device - Allocate a new SPI device
 539  * @ctlr: Controller to which device is connected
 540  * Context: can sleep
 541  *
 542  * Allows a driver to allocate and initialize a spi_device without
 543  * registering it immediately.  This allows a driver to directly
 544  * fill the spi_device with device parameters before calling
 545  * spi_add_device() on it.
 546  *
 547  * Caller is responsible to call spi_add_device() on the returned
 548  * spi_device structure to add it to the SPI controller.  If the caller
 549  * needs to discard the spi_device without adding it, then it should
 550  * call spi_dev_put() on it.
 551  *
 552  * Return: a pointer to the new device, or NULL.
 553  */
 554 struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
 555 {
 556         struct spi_device       *spi;
 557
 558         if (!spi_controller_get(ctlr))
 559                 return NULL;
 560
 561         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 562         if (!spi) {
 563                 spi_controller_put(ctlr);
 564                 return NULL;
 565         }
 566
 567         spi->pcpu_statistics = spi_alloc_pcpu_stats(NULL);
 568         if (!spi->pcpu_statistics) {
 569                 kfree(spi);
 570                 spi_controller_put(ctlr);
 571                 return NULL;
 572         }
 573
 574         spi->master = spi->controller = ctlr;
 575         spi->dev.parent = &ctlr->dev;
 576         spi->dev.bus = &spi_bus_type;
 577         spi->dev.release = spidev_release;
 578         spi->mode = ctlr->buswidth_override_bits;
 579
 580         device_initialize(&spi->dev);
 581         return spi;
 582 }
 583 EXPORT_SYMBOL_GPL(spi_alloc_device);
 584
 585 static void spi_dev_set_name(struct spi_device *spi)
 586 {
 587         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 588
 589         if (adev) {
 590                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 591                 return;
 592         }
 593
 594         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->controller->dev),
 595                      spi->chip_select);
 596 }
 597
 598 static int spi_dev_check(struct device *dev, void *data)
 599 {
 600         struct spi_device *spi = to_spi_device(dev);
 601         struct spi_device *new_spi = data;
 602
 603         if (spi->controller == new_spi->controller &&
 604             spi->chip_select == new_spi->chip_select)
 605                 return -EBUSY;
 606         return 0;
 607 }
 608
 609 static void spi_cleanup(struct spi_device *spi)
 610 {
 611         if (spi->controller->cleanup)
 612                 spi->controller->cleanup(spi);
 613 }
 614
 615 static int __spi_add_device(struct spi_device *spi)
 616 {
 617         struct spi_controller *ctlr = spi->controller;
 618         struct device *dev = ctlr->dev.parent;
 619         int status;
 620
 621         /*
 622          * We need to make sure there's no other device with this
 623          * chipselect **BEFORE** we call setup(), else we'll trash
 624          * its configuration.
 625          */
 626         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 627         if (status) {
 628                 dev_err(dev, "chipselect %d already in use\n",
 629                                 spi->chip_select);
 630                 return status;
 631         }
 632
 633         /* Controller may unregister concurrently */
 634         if (IS_ENABLED(CONFIG_SPI_DYNAMIC) &&
 635             !device_is_registered(&ctlr->dev)) {
 636                 return -ENODEV;
 637         }
 638
 639         if (ctlr->cs_gpiods)
 640                 spi->cs_gpiod = ctlr->cs_gpiods[spi->chip_select];
 641
 642         /*
 643          * Drivers may modify this initial i/o setup, but will
 644          * normally rely on the device being setup.  Devices
 645          * using SPI_CS_HIGH can't coexist well otherwise...
 646          */
 647         status = spi_setup(spi);
 648         if (status < 0) {
 649                 dev_err(dev, "can't setup %s, status %d\n",
 650                                 dev_name(&spi->dev), status);
 651                 return status;
 652         }
 653
 654         /* Device may be bound to an active driver when this returns */
 655         status = device_add(&spi->dev);
 656         if (status < 0) {
 657                 dev_err(dev, "can't add %s, status %d\n",
 658                                 dev_name(&spi->dev), status);
 659                 spi_cleanup(spi);
 660         } else {
 661                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 662         }
 663
 664         return status;
 665 }
 666
 667 /**
 668  * spi_add_device - Add spi_device allocated with spi_alloc_device
 669  * @spi: spi_device to register
 670  *
 671  * Companion function to spi_alloc_device.  Devices allocated with
 672  * spi_alloc_device can be added onto the spi bus with this function.
 673  *
 674  * Return: 0 on success; negative errno on failure
 675  */
 676 int spi_add_device(struct spi_device *spi)
 677 {
 678         struct spi_controller *ctlr = spi->controller;
 679         struct device *dev = ctlr->dev.parent;
 680         int status;
 681
 682         /* Chipselects are numbered 0..max; validate. */
 683         if (spi->chip_select >= ctlr->num_chipselect) {
 684                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 685                         ctlr->num_chipselect);
 686                 return -EINVAL;
 687         }
 688
 689         /* Set the bus ID string */
 690         spi_dev_set_name(spi);
 691
 692         mutex_lock(&ctlr->add_lock);
 693         status = __spi_add_device(spi);
 694         mutex_unlock(&ctlr->add_lock);
 695         return status;
 696 }
 697 EXPORT_SYMBOL_GPL(spi_add_device);
 698
 699 static int spi_add_device_locked(struct spi_device *spi)
 700 {
 701         struct spi_controller *ctlr = spi->controller;
 702         struct device *dev = ctlr->dev.parent;
 703
 704         /* Chipselects are numbered 0..max; validate. */
 705         if (spi->chip_select >= ctlr->num_chipselect) {
 706                 dev_err(dev, "cs%d >= max %d\n", spi->chip_select,
 707                         ctlr->num_chipselect);
 708                 return -EINVAL;
 709         }
 710
 711         /* Set the bus ID string */
 712         spi_dev_set_name(spi);
 713
 714         WARN_ON(!mutex_is_locked(&ctlr->add_lock));
 715         return __spi_add_device(spi);
 716 }
 717
 718 /**
 719  * spi_new_device - instantiate one new SPI device
 720  * @ctlr: Controller to which device is connected
 721  * @chip: Describes the SPI device
 722  * Context: can sleep
 723  *
 724  * On typical mainboards, this is purely internal; and it's not needed
 725  * after board init creates the hard-wired devices.  Some development
 726  * platforms may not be able to use spi_register_board_info though, and
 727  * this is exported so that for example a USB or parport based adapter
 728  * driver could add devices (which it would learn about out-of-band).
 729  *
 730  * Return: the new device, or NULL.
 731  */
 732 struct spi_device *spi_new_device(struct spi_controller *ctlr,
 733                                   struct spi_board_info *chip)
 734 {
 735         struct spi_device       *proxy;
 736         int                     status;
 737
 738         /*
 739          * NOTE:  caller did any chip->bus_num checks necessary.
 740          *
 741          * Also, unless we change the return value convention to use
 742          * error-or-pointer (not NULL-or-pointer), troubleshootability
 743          * suggests syslogged diagnostics are best here (ugh).
 744          */
 745
 746         proxy = spi_alloc_device(ctlr);
 747         if (!proxy)
 748                 return NULL;
 749
 750         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 751
 752         proxy->chip_select = chip->chip_select;
 753         proxy->max_speed_hz = chip->max_speed_hz;
 754         proxy->mode = chip->mode;
 755         proxy->irq = chip->irq;
 756         strscpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 757         proxy->dev.platform_data = (void *) chip->platform_data;
 758         proxy->controller_data = chip->controller_data;
 759         proxy->controller_state = NULL;
 760
 761         if (chip->swnode) {
 762                 status = device_add_software_node(&proxy->dev, chip->swnode);
 763                 if (status) {
 764                         dev_err(&ctlr->dev, "failed to add software node to '%s': %d\n",
 765                                 chip->modalias, status);
 766                         goto err_dev_put;
 767                 }
 768         }
 769
 770         status = spi_add_device(proxy);
 771         if (status < 0)
 772                 goto err_dev_put;
 773
 774         return proxy;
 775
 776 err_dev_put:
 777         device_remove_software_node(&proxy->dev);
 778         spi_dev_put(proxy);
 779         return NULL;
 780 }
 781 EXPORT_SYMBOL_GPL(spi_new_device);
 782
 783 /**
 784  * spi_unregister_device - unregister a single SPI device
 785  * @spi: spi_device to unregister
 786  *
 787  * Start making the passed SPI device vanish. Normally this would be handled
 788  * by spi_unregister_controller().
 789  */
 790 void spi_unregister_device(struct spi_device *spi)
 791 {
 792         if (!spi)
 793                 return;
 794
 795         if (spi->dev.of_node) {
 796                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 797                 of_node_put(spi->dev.of_node);
 798         }
 799         if (ACPI_COMPANION(&spi->dev))
 800                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 801         device_remove_software_node(&spi->dev);
 802         device_del(&spi->dev);
 803         spi_cleanup(spi);
 804         put_device(&spi->dev);
 805 }
 806 EXPORT_SYMBOL_GPL(spi_unregister_device);
 807
 808 static void spi_match_controller_to_boardinfo(struct spi_controller *ctlr,
 809                                               struct spi_board_info *bi)
 810 {
 811         struct spi_device *dev;
 812
 813         if (ctlr->bus_num != bi->bus_num)
 814                 return;
 815
 816         dev = spi_new_device(ctlr, bi);
 817         if (!dev)
 818                 dev_err(ctlr->dev.parent, "can't create new device for %s\n",
 819                         bi->modalias);
 820 }
 821
 822 /**
 823  * spi_register_board_info - register SPI devices for a given board
 824  * @info: array of chip descriptors
 825  * @n: how many descriptors are provided
 826  * Context: can sleep
 827  *
 828  * Board-specific early init code calls this (probably during arch_initcall)
 829  * with segments of the SPI device table.  Any device nodes are created later,
 830  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 831  * this table of devices forever, so that reloading a controller driver will
 832  * not make Linux forget about these hard-wired devices.
 833  *
 834  * Other code can also call this, e.g. a particular add-on board might provide
 835  * SPI devices through its expansion connector, so code initializing that board
 836  * would naturally declare its SPI devices.
 837  *
 838  * The board info passed can safely be __initdata ... but be careful of
 839  * any embedded pointers (platform_data, etc), they're copied as-is.
 840  *
 841  * Return: zero on success, else a negative error code.
 842  */
 843 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 844 {
 845         struct boardinfo *bi;
 846         int i;
 847
 848         if (!n)
 849                 return 0;
 850
 851         bi = kcalloc(n, sizeof(*bi), GFP_KERNEL);
 852         if (!bi)
 853                 return -ENOMEM;
 854
 855         for (i = 0; i < n; i++, bi++, info++) {
 856                 struct spi_controller *ctlr;
 857
 858                 memcpy(&bi->board_info, info, sizeof(*info));
 859
 860                 mutex_lock(&board_lock);
 861                 list_add_tail(&bi->list, &board_list);
 862                 list_for_each_entry(ctlr, &spi_controller_list, list)
 863                         spi_match_controller_to_boardinfo(ctlr,
 864                                                           &bi->board_info);
 865                 mutex_unlock(&board_lock);
 866         }
 867
 868         return 0;
 869 }
 870
 871 /*-------------------------------------------------------------------------*/
 872
 873 /* Core methods for SPI resource management */
 874
 875 /**
 876  * spi_res_alloc - allocate a spi resource that is life-cycle managed
 877  *                 during the processing of a spi_message while using
 878  *                 spi_transfer_one
 879  * @spi:     the spi device for which we allocate memory
 880  * @release: the release code to execute for this resource
 881  * @size:    size to alloc and return
 882  * @gfp:     GFP allocation flags
 883  *
 884  * Return: the pointer to the allocated data
 885  *
 886  * This may get enhanced in the future to allocate from a memory pool
 887  * of the @spi_device or @spi_controller to avoid repeated allocations.
 888  */
 889 static void *spi_res_alloc(struct spi_device *spi, spi_res_release_t release,
 890                            size_t size, gfp_t gfp)
 891 {
 892         struct spi_res *sres;
 893
 894         sres = kzalloc(sizeof(*sres) + size, gfp);
 895         if (!sres)
 896                 return NULL;
 897
 898         INIT_LIST_HEAD(&sres->entry);
 899         sres->release = release;
 900
 901         return sres->data;
 902 }
 903
 904 /**
 905  * spi_res_free - free an spi resource
 906  * @res: pointer to the custom data of a resource
 907  */
 908 static void spi_res_free(void *res)
 909 {
 910         struct spi_res *sres = container_of(res, struct spi_res, data);
 911
 912         if (!res)
 913                 return;
 914
 915         WARN_ON(!list_empty(&sres->entry));
 916         kfree(sres);
 917 }
 918
 919 /**
 920  * spi_res_add - add a spi_res to the spi_message
 921  * @message: the spi message
 922  * @res:     the spi_resource
 923  */
 924 static void spi_res_add(struct spi_message *message, void *res)
 925 {
 926         struct spi_res *sres = container_of(res, struct spi_res, data);
 927
 928         WARN_ON(!list_empty(&sres->entry));
 929         list_add_tail(&sres->entry, &message->resources);
 930 }
 931
 932 /**
 933  * spi_res_release - release all spi resources for this message
 934  * @ctlr:  the @spi_controller
 935  * @message: the @spi_message
 936  */
 937 static void spi_res_release(struct spi_controller *ctlr, struct spi_message *message)
 938 {
 939         struct spi_res *res, *tmp;
 940
 941         list_for_each_entry_safe_reverse(res, tmp, &message->resources, entry) {
 942                 if (res->release)
 943                         res->release(ctlr, message, res->data);
 944
 945                 list_del(&res->entry);
 946
 947                 kfree(res);
 948         }
 949 }
 950
 951 /*-------------------------------------------------------------------------*/
 952
 953 static void spi_set_cs(struct spi_device *spi, bool enable, bool force)
 954 {
 955         bool activate = enable;
 956
 957         /*
 958          * Avoid calling into the driver (or doing delays) if the chip select
 959          * isn't actually changing from the last time this was called.
 960          */
 961         if (!force && ((enable && spi->controller->last_cs == spi->chip_select) ||
 962                                 (!enable && spi->controller->last_cs != spi->chip_select)) &&
 963             (spi->controller->last_cs_mode_high == (spi->mode & SPI_CS_HIGH)))
 964                 return;
 965
 966         trace_spi_set_cs(spi, activate);
 967
 968         spi->controller->last_cs = enable ? spi->chip_select : -1;
 969         spi->controller->last_cs_mode_high = spi->mode & SPI_CS_HIGH;
 970
 971         if ((spi->cs_gpiod || !spi->controller->set_cs_timing) && !activate) {
 972                 spi_delay_exec(&spi->cs_hold, NULL);
 973         }
 974
 975         if (spi->mode & SPI_CS_HIGH)
 976                 enable = !enable;
 977
 978         if (spi->cs_gpiod) {
 979                 if (!(spi->mode & SPI_NO_CS)) {
 980                         /*
 981                          * Historically ACPI has no means of the GPIO polarity and
 982                          * thus the SPISerialBus() resource defines it on the per-chip
 983                          * basis. In order to avoid a chain of negations, the GPIO
 984                          * polarity is considered being Active High. Even for the cases
 985                          * when _DSD() is involved (in the updated versions of ACPI)
 986                          * the GPIO CS polarity must be defined Active High to avoid
 987                          * ambiguity. That's why we use enable, that takes SPI_CS_HIGH
 988                          * into account.
 989                          */
 990                         if (has_acpi_companion(&spi->dev))
 991                                 gpiod_set_value_cansleep(spi->cs_gpiod, !enable);
 992                         else
 993                                 /* Polarity handled by GPIO library */
 994                                 gpiod_set_value_cansleep(spi->cs_gpiod, activate);
 995                 }
 996                 /* Some SPI masters need both GPIO CS & slave_select */
 997                 if ((spi->controller->flags & SPI_MASTER_GPIO_SS) &&
 998                     spi->controller->set_cs)
 999                         spi->controller->set_cs(spi, !enable);
1000         } else if (spi->controller->set_cs) {
1001                 spi->controller->set_cs(spi, !enable);
1002         }
1003
1004         if (spi->cs_gpiod || !spi->controller->set_cs_timing) {
1005                 if (activate)
1006                         spi_delay_exec(&spi->cs_setup, NULL);
1007                 else
1008                         spi_delay_exec(&spi->cs_inactive, NULL);
1009         }
1010 }
1011
1012 #ifdef CONFIG_HAS_DMA
1013 static int spi_map_buf_attrs(struct spi_controller *ctlr, struct device *dev,
1014                              struct sg_table *sgt, void *buf, size_t len,
1015                              enum dma_data_direction dir, unsigned long attrs)
1016 {
1017         const bool vmalloced_buf = is_vmalloc_addr(buf);
1018         unsigned int max_seg_size = dma_get_max_seg_size(dev);
1019 #ifdef CONFIG_HIGHMEM
1020         const bool kmap_buf = ((unsigned long)buf >= PKMAP_BASE &&
1021                                 (unsigned long)buf < (PKMAP_BASE +
1022                                         (LAST_PKMAP * PAGE_SIZE)));
1023 #else
1024         const bool kmap_buf = false;
1025 #endif
1026         int desc_len;
1027         int sgs;
1028         struct page *vm_page;
1029         struct scatterlist *sg;
1030         void *sg_buf;
1031         size_t min;
1032         int i, ret;
1033
1034         if (vmalloced_buf || kmap_buf) {
1035                 desc_len = min_t(unsigned long, max_seg_size, PAGE_SIZE);
1036                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
1037         } else if (virt_addr_valid(buf)) {
1038                 desc_len = min_t(size_t, max_seg_size, ctlr->max_dma_len);
1039                 sgs = DIV_ROUND_UP(len, desc_len);
1040         } else {
1041                 return -EINVAL;
1042         }
1043
1044         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
1045         if (ret != 0)
1046                 return ret;
1047
1048         sg = &sgt->sgl[0];
1049         for (i = 0; i < sgs; i++) {
1050
1051                 if (vmalloced_buf || kmap_buf) {
1052                         /*
1053                          * Next scatterlist entry size is the minimum between
1054                          * the desc_len and the remaining buffer length that
1055                          * fits in a page.
1056                          */
1057                         min = min_t(size_t, desc_len,
1058                                     min_t(size_t, len,
1059                                           PAGE_SIZE - offset_in_page(buf)));
1060                         if (vmalloced_buf)
1061                                 vm_page = vmalloc_to_page(buf);
1062                         else
1063                                 vm_page = kmap_to_page(buf);
1064                         if (!vm_page) {
1065                                 sg_free_table(sgt);
1066                                 return -ENOMEM;
1067                         }
1068                         sg_set_page(sg, vm_page,
1069                                     min, offset_in_page(buf));
1070                 } else {
1071                         min = min_t(size_t, len, desc_len);
1072                         sg_buf = buf;
1073                         sg_set_buf(sg, sg_buf, min);
1074                 }
1075
1076                 buf += min;
1077                 len -= min;
1078                 sg = sg_next(sg);
1079         }
1080
1081         ret = dma_map_sgtable(dev, sgt, dir, attrs);
1082         if (ret < 0) {
1083                 sg_free_table(sgt);
1084                 return ret;
1085         }
1086
1087         return 0;
1088 }
1089
1090 int spi_map_buf(struct spi_controller *ctlr, struct device *dev,
1091                 struct sg_table *sgt, void *buf, size_t len,
1092                 enum dma_data_direction dir)
1093 {
1094         return spi_map_buf_attrs(ctlr, dev, sgt, buf, len, dir, 0);
1095 }
1096
1097 static void spi_unmap_buf_attrs(struct spi_controller *ctlr,
1098                                 struct device *dev, struct sg_table *sgt,
1099                                 enum dma_data_direction dir,
1100                                 unsigned long attrs)
1101 {
1102         if (sgt->orig_nents) {
1103                 dma_unmap_sgtable(dev, sgt, dir, attrs);
1104                 sg_free_table(sgt);
1105                 sgt->orig_nents = 0;
1106                 sgt->nents = 0;
1107         }
1108 }
1109
1110 void spi_unmap_buf(struct spi_controller *ctlr, struct device *dev,
1111                    struct sg_table *sgt, enum dma_data_direction dir)
1112 {
1113         spi_unmap_buf_attrs(ctlr, dev, sgt, dir, 0);
1114 }
1115
1116 static int __spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1117 {
1118         struct device *tx_dev, *rx_dev;
1119         struct spi_transfer *xfer;
1120         int ret;
1121
1122         if (!ctlr->can_dma)
1123                 return 0;
1124
1125         if (ctlr->dma_tx)
1126                 tx_dev = ctlr->dma_tx->device->dev;
1127         else if (ctlr->dma_map_dev)
1128                 tx_dev = ctlr->dma_map_dev;
1129         else
1130                 tx_dev = ctlr->dev.parent;
1131
1132         if (ctlr->dma_rx)
1133                 rx_dev = ctlr->dma_rx->device->dev;
1134         else if (ctlr->dma_map_dev)
1135                 rx_dev = ctlr->dma_map_dev;
1136         else
1137                 rx_dev = ctlr->dev.parent;
1138
1139         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1140                 /* The sync is done before each transfer. */
1141                 unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC;
1142
1143                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1144                         continue;
1145
1146                 if (xfer->tx_buf != NULL) {
1147                         ret = spi_map_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
1148                                                 (void *)xfer->tx_buf,
1149                                                 xfer->len, DMA_TO_DEVICE,
1150                                                 attrs);
1151                         if (ret != 0)
1152                                 return ret;
1153                 }
1154
1155                 if (xfer->rx_buf != NULL) {
1156                         ret = spi_map_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
1157                                                 xfer->rx_buf, xfer->len,
1158                                                 DMA_FROM_DEVICE, attrs);
1159                         if (ret != 0) {
1160                                 spi_unmap_buf_attrs(ctlr, tx_dev,
1161                                                 &xfer->tx_sg, DMA_TO_DEVICE,
1162                                                 attrs);
1163
1164                                 return ret;
1165                         }
1166                 }
1167         }
1168
1169         ctlr->cur_rx_dma_dev = rx_dev;
1170         ctlr->cur_tx_dma_dev = tx_dev;
1171         ctlr->cur_msg_mapped = true;
1172
1173         return 0;
1174 }
1175
1176 static int __spi_unmap_msg(struct spi_controller *ctlr, struct spi_message *msg)
1177 {
1178         struct device *rx_dev = ctlr->cur_rx_dma_dev;
1179         struct device *tx_dev = ctlr->cur_tx_dma_dev;
1180         struct spi_transfer *xfer;
1181
1182         if (!ctlr->cur_msg_mapped || !ctlr->can_dma)
1183                 return 0;
1184
1185         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1186                 /* The sync has already been done after each transfer. */
1187                 unsigned long attrs = DMA_ATTR_SKIP_CPU_SYNC;
1188
1189                 if (!ctlr->can_dma(ctlr, msg->spi, xfer))
1190                         continue;
1191
1192                 spi_unmap_buf_attrs(ctlr, rx_dev, &xfer->rx_sg,
1193                                     DMA_FROM_DEVICE, attrs);
1194                 spi_unmap_buf_attrs(ctlr, tx_dev, &xfer->tx_sg,
1195                                     DMA_TO_DEVICE, attrs);
1196         }
1197
1198         ctlr->cur_msg_mapped = false;
1199
1200         return 0;
1201 }
1202
1203 static void spi_dma_sync_for_device(struct spi_controller *ctlr,
1204                                     struct spi_transfer *xfer)
1205 {
1206         struct device *rx_dev = ctlr->cur_rx_dma_dev;
1207         struct device *tx_dev = ctlr->cur_tx_dma_dev;
1208
1209         if (!ctlr->cur_msg_mapped)
1210                 return;
1211
1212         if (xfer->tx_sg.orig_nents)
1213                 dma_sync_sgtable_for_device(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1214         if (xfer->rx_sg.orig_nents)
1215                 dma_sync_sgtable_for_device(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1216 }
1217
1218 static void spi_dma_sync_for_cpu(struct spi_controller *ctlr,
1219                                  struct spi_transfer *xfer)
1220 {
1221         struct device *rx_dev = ctlr->cur_rx_dma_dev;
1222         struct device *tx_dev = ctlr->cur_tx_dma_dev;
1223
1224         if (!ctlr->cur_msg_mapped)
1225                 return;
1226
1227         if (xfer->rx_sg.orig_nents)
1228                 dma_sync_sgtable_for_cpu(rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
1229         if (xfer->tx_sg.orig_nents)
1230                 dma_sync_sgtable_for_cpu(tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
1231 }
1232 #else /* !CONFIG_HAS_DMA */
1233 static inline int __spi_map_msg(struct spi_controller *ctlr,
1234                                 struct spi_message *msg)
1235 {
1236         return 0;
1237 }
1238
1239 static inline int __spi_unmap_msg(struct spi_controller *ctlr,
1240                                   struct spi_message *msg)
1241 {
1242         return 0;
1243 }
1244
1245 static void spi_dma_sync_for_device(struct spi_controller *ctrl,
1246                                     struct spi_transfer *xfer)
1247 {
1248 }
1249
1250 static void spi_dma_sync_for_cpu(struct spi_controller *ctrl,
1251                                  struct spi_transfer *xfer)
1252 {
1253 }
1254 #endif /* !CONFIG_HAS_DMA */
1255
1256 static inline int spi_unmap_msg(struct spi_controller *ctlr,
1257                                 struct spi_message *msg)
1258 {
1259         struct spi_transfer *xfer;
1260
1261         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1262                 /*
1263                  * Restore the original value of tx_buf or rx_buf if they are
1264                  * NULL.
1265                  */
1266                 if (xfer->tx_buf == ctlr->dummy_tx)
1267                         xfer->tx_buf = NULL;
1268                 if (xfer->rx_buf == ctlr->dummy_rx)
1269                         xfer->rx_buf = NULL;
1270         }
1271
1272         return __spi_unmap_msg(ctlr, msg);
1273 }
1274
1275 static int spi_map_msg(struct spi_controller *ctlr, struct spi_message *msg)
1276 {
1277         struct spi_transfer *xfer;
1278         void *tmp;
1279         unsigned int max_tx, max_rx;
1280
1281         if ((ctlr->flags & (SPI_CONTROLLER_MUST_RX | SPI_CONTROLLER_MUST_TX))
1282                 && !(msg->spi->mode & SPI_3WIRE)) {
1283                 max_tx = 0;
1284                 max_rx = 0;
1285
1286                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1287                         if ((ctlr->flags & SPI_CONTROLLER_MUST_TX) &&
1288                             !xfer->tx_buf)
1289                                 max_tx = max(xfer->len, max_tx);
1290                         if ((ctlr->flags & SPI_CONTROLLER_MUST_RX) &&
1291                             !xfer->rx_buf)
1292                                 max_rx = max(xfer->len, max_rx);
1293                 }
1294
1295                 if (max_tx) {
1296                         tmp = krealloc(ctlr->dummy_tx, max_tx,
1297                                        GFP_KERNEL | GFP_DMA | __GFP_ZERO);
1298                         if (!tmp)
1299                                 return -ENOMEM;
1300                         ctlr->dummy_tx = tmp;
1301                 }
1302
1303                 if (max_rx) {
1304                         tmp = krealloc(ctlr->dummy_rx, max_rx,
1305                                        GFP_KERNEL | GFP_DMA);
1306                         if (!tmp)
1307                                 return -ENOMEM;
1308                         ctlr->dummy_rx = tmp;
1309                 }
1310
1311                 if (max_tx || max_rx) {
1312                         list_for_each_entry(xfer, &msg->transfers,
1313                                             transfer_list) {
1314                                 if (!xfer->len)
1315                                         continue;
1316                                 if (!xfer->tx_buf)
1317                                         xfer->tx_buf = ctlr->dummy_tx;
1318                                 if (!xfer->rx_buf)
1319                                         xfer->rx_buf = ctlr->dummy_rx;
1320                         }
1321                 }
1322         }
1323
1324         return __spi_map_msg(ctlr, msg);
1325 }
1326
1327 static int spi_transfer_wait(struct spi_controller *ctlr,
1328                              struct spi_message *msg,
1329                              struct spi_transfer *xfer)
1330 {
1331         struct spi_statistics __percpu *statm = ctlr->pcpu_statistics;
1332         struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
1333         u32 speed_hz = xfer->speed_hz;
1334         unsigned long long ms;
1335
1336         if (spi_controller_is_slave(ctlr)) {
1337                 if (wait_for_completion_interruptible(&ctlr->xfer_completion)) {
1338                         dev_dbg(&msg->spi->dev, "SPI transfer interrupted\n");
1339                         return -EINTR;
1340                 }
1341         } else {
1342                 if (!speed_hz)
1343                         speed_hz = 100000;
1344
1345                 /*
1346                  * For each byte we wait for 8 cycles of the SPI clock.
1347                  * Since speed is defined in Hz and we want milliseconds,
1348                  * use respective multiplier, but before the division,
1349                  * otherwise we may get 0 for short transfers.
1350                  */
1351                 ms = 8LL * MSEC_PER_SEC * xfer->len;
1352                 do_div(ms, speed_hz);
1353
1354                 /*
1355                  * Increase it twice and add 200 ms tolerance, use
1356                  * predefined maximum in case of overflow.
1357                  */
1358                 ms += ms + 200;
1359                 if (ms > UINT_MAX)
1360                         ms = UINT_MAX;
1361
1362                 ms = wait_for_completion_timeout(&ctlr->xfer_completion,
1363                                                  msecs_to_jiffies(ms));
1364
1365                 if (ms == 0) {
1366                         SPI_STATISTICS_INCREMENT_FIELD(statm, timedout);
1367                         SPI_STATISTICS_INCREMENT_FIELD(stats, timedout);
1368                         dev_err(&msg->spi->dev,
1369                                 "SPI transfer timed out\n");
1370                         return -ETIMEDOUT;
1371                 }
1372         }
1373
1374         return 0;
1375 }
1376
1377 static void _spi_transfer_delay_ns(u32 ns)
1378 {
1379         if (!ns)
1380                 return;
1381         if (ns <= NSEC_PER_USEC) {
1382                 ndelay(ns);
1383         } else {
1384                 u32 us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
1385
1386                 if (us <= 10)
1387                         udelay(us);
1388                 else
1389                         usleep_range(us, us + DIV_ROUND_UP(us, 10));
1390         }
1391 }
1392
1393 int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer)
1394 {
1395         u32 delay = _delay->value;
1396         u32 unit = _delay->unit;
1397         u32 hz;
1398
1399         if (!delay)
1400                 return 0;
1401
1402         switch (unit) {
1403         case SPI_DELAY_UNIT_USECS:
1404                 delay *= NSEC_PER_USEC;
1405                 break;
1406         case SPI_DELAY_UNIT_NSECS:
1407                 /* Nothing to do here */
1408                 break;
1409         case SPI_DELAY_UNIT_SCK:
1410                 /* Clock cycles need to be obtained from spi_transfer */
1411                 if (!xfer)
1412                         return -EINVAL;
1413                 /*
1414                  * If there is unknown effective speed, approximate it
1415                  * by underestimating with half of the requested hz.
1416                  */
1417                 hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2;
1418                 if (!hz)
1419                         return -EINVAL;
1420
1421                 /* Convert delay to nanoseconds */
1422                 delay *= DIV_ROUND_UP(NSEC_PER_SEC, hz);
1423                 break;
1424         default:
1425                 return -EINVAL;
1426         }
1427
1428         return delay;
1429 }
1430 EXPORT_SYMBOL_GPL(spi_delay_to_ns);
1431
1432 int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer)
1433 {
1434         int delay;
1435
1436         might_sleep();
1437
1438         if (!_delay)
1439                 return -EINVAL;
1440
1441         delay = spi_delay_to_ns(_delay, xfer);
1442         if (delay < 0)
1443                 return delay;
1444
1445         _spi_transfer_delay_ns(delay);
1446
1447         return 0;
1448 }
1449 EXPORT_SYMBOL_GPL(spi_delay_exec);
1450
1451 static void _spi_transfer_cs_change_delay(struct spi_message *msg,
1452                                           struct spi_transfer *xfer)
1453 {
1454         u32 default_delay_ns = 10 * NSEC_PER_USEC;
1455         u32 delay = xfer->cs_change_delay.value;
1456         u32 unit = xfer->cs_change_delay.unit;
1457         int ret;
1458
1459         /* Return early on "fast" mode - for everything but USECS */
1460         if (!delay) {
1461                 if (unit == SPI_DELAY_UNIT_USECS)
1462                         _spi_transfer_delay_ns(default_delay_ns);
1463                 return;
1464         }
1465
1466         ret = spi_delay_exec(&xfer->cs_change_delay, xfer);
1467         if (ret) {
1468                 dev_err_once(&msg->spi->dev,
1469                              "Use of unsupported delay unit %i, using default of %luus\n",
1470                              unit, default_delay_ns / NSEC_PER_USEC);
1471                 _spi_transfer_delay_ns(default_delay_ns);
1472         }
1473 }
1474
1475 /*
1476  * spi_transfer_one_message - Default implementation of transfer_one_message()
1477  *
1478  * This is a standard implementation of transfer_one_message() for
1479  * drivers which implement a transfer_one() operation.  It provides
1480  * standard handling of delays and chip select management.
1481  */
1482 static int spi_transfer_one_message(struct spi_controller *ctlr,
1483                                     struct spi_message *msg)
1484 {
1485         struct spi_transfer *xfer;
1486         bool keep_cs = false;
1487         int ret = 0;
1488         struct spi_statistics __percpu *statm = ctlr->pcpu_statistics;
1489         struct spi_statistics __percpu *stats = msg->spi->pcpu_statistics;
1490
1491         xfer = list_first_entry(&msg->transfers, struct spi_transfer, transfer_list);
1492         spi_set_cs(msg->spi, !xfer->cs_off, false);
1493
1494         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
1495         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
1496
1497         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1498                 trace_spi_transfer_start(msg, xfer);
1499
1500                 spi_statistics_add_transfer_stats(statm, xfer, ctlr);
1501                 spi_statistics_add_transfer_stats(stats, xfer, ctlr);
1502
1503                 if (!ctlr->ptp_sts_supported) {
1504                         xfer->ptp_sts_word_pre = 0;
1505                         ptp_read_system_prets(xfer->ptp_sts);
1506                 }
1507
1508                 if ((xfer->tx_buf || xfer->rx_buf) && xfer->len) {
1509                         reinit_completion(&ctlr->xfer_completion);
1510
1511 fallback_pio:
1512                         spi_dma_sync_for_device(ctlr, xfer);
1513                         ret = ctlr->transfer_one(ctlr, msg->spi, xfer);
1514                         if (ret < 0) {
1515                                 spi_dma_sync_for_cpu(ctlr, xfer);
1516
1517                                 if (ctlr->cur_msg_mapped &&
1518                                    (xfer->error & SPI_TRANS_FAIL_NO_START)) {
1519                                         __spi_unmap_msg(ctlr, msg);
1520                                         ctlr->fallback = true;
1521                                         xfer->error &= ~SPI_TRANS_FAIL_NO_START;
1522                                         goto fallback_pio;
1523                                 }
1524
1525                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1526                                                                errors);
1527                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1528                                                                errors);
1529                                 dev_err(&msg->spi->dev,
1530                                         "SPI transfer failed: %d\n", ret);
1531                                 goto out;
1532                         }
1533
1534                         if (ret > 0) {
1535                                 ret = spi_transfer_wait(ctlr, msg, xfer);
1536                                 if (ret < 0)
1537                                         msg->status = ret;
1538                         }
1539
1540                         spi_dma_sync_for_cpu(ctlr, xfer);
1541                 } else {
1542                         if (xfer->len)
1543                                 dev_err(&msg->spi->dev,
1544                                         "Bufferless transfer has length %u\n",
1545                                         xfer->len);
1546                 }
1547
1548                 if (!ctlr->ptp_sts_supported) {
1549                         ptp_read_system_postts(xfer->ptp_sts);
1550                         xfer->ptp_sts_word_post = xfer->len;
1551                 }
1552
1553                 trace_spi_transfer_stop(msg, xfer);
1554
1555                 if (msg->status != -EINPROGRESS)
1556                         goto out;
1557
1558                 spi_transfer_delay_exec(xfer);
1559
1560                 if (xfer->cs_change) {
1561                         if (list_is_last(&xfer->transfer_list,
1562                                          &msg->transfers)) {
1563                                 keep_cs = true;
1564                         } else {
1565                                 if (!xfer->cs_off)
1566                                         spi_set_cs(msg->spi, false, false);
1567                                 _spi_transfer_cs_change_delay(msg, xfer);
1568                                 if (!list_next_entry(xfer, transfer_list)->cs_off)
1569                                         spi_set_cs(msg->spi, true, false);
1570                         }
1571                 } else if (!list_is_last(&xfer->transfer_list, &msg->transfers) &&
1572                            xfer->cs_off != list_next_entry(xfer, transfer_list)->cs_off) {
1573                         spi_set_cs(msg->spi, xfer->cs_off, false);
1574                 }
1575
1576                 msg->actual_length += xfer->len;
1577         }
1578
1579 out:
1580         if (ret != 0 || !keep_cs)
1581                 spi_set_cs(msg->spi, false, false);
1582
1583         if (msg->status == -EINPROGRESS)
1584                 msg->status = ret;
1585
1586         if (msg->status && ctlr->handle_err)
1587                 ctlr->handle_err(ctlr, msg);
1588
1589         spi_finalize_current_message(ctlr);
1590
1591         return ret;
1592 }
1593
1594 /**
1595  * spi_finalize_current_transfer - report completion of a transfer
1596  * @ctlr: the controller reporting completion
1597  *
1598  * Called by SPI drivers using the core transfer_one_message()
1599  * implementation to notify it that the current interrupt driven
1600  * transfer has finished and the next one may be scheduled.
1601  */
1602 void spi_finalize_current_transfer(struct spi_controller *ctlr)
1603 {
1604         complete(&ctlr->xfer_completion);
1605 }
1606 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1607
1608 static void spi_idle_runtime_pm(struct spi_controller *ctlr)
1609 {
1610         if (ctlr->auto_runtime_pm) {
1611                 pm_runtime_mark_last_busy(ctlr->dev.parent);
1612                 pm_runtime_put_autosuspend(ctlr->dev.parent);
1613         }
1614 }
1615
1616 static int __spi_pump_transfer_message(struct spi_controller *ctlr,
1617                 struct spi_message *msg, bool was_busy)
1618 {
1619         struct spi_transfer *xfer;
1620         int ret;
1621
1622         if (!was_busy && ctlr->auto_runtime_pm) {
1623                 ret = pm_runtime_get_sync(ctlr->dev.parent);
1624                 if (ret < 0) {
1625                         pm_runtime_put_noidle(ctlr->dev.parent);
1626                         dev_err(&ctlr->dev, "Failed to power device: %d\n",
1627                                 ret);
1628                         return ret;
1629                 }
1630         }
1631
1632         if (!was_busy)
1633                 trace_spi_controller_busy(ctlr);
1634
1635         if (!was_busy && ctlr->prepare_transfer_hardware) {
1636                 ret = ctlr->prepare_transfer_hardware(ctlr);
1637                 if (ret) {
1638                         dev_err(&ctlr->dev,
1639                                 "failed to prepare transfer hardware: %d\n",
1640                                 ret);
1641
1642                         if (ctlr->auto_runtime_pm)
1643                                 pm_runtime_put(ctlr->dev.parent);
1644
1645                         msg->status = ret;
1646                         spi_finalize_current_message(ctlr);
1647
1648                         return ret;
1649                 }
1650         }
1651
1652         trace_spi_message_start(msg);
1653
1654         ret = spi_split_transfers_maxsize(ctlr, msg,
1655                                           spi_max_transfer_size(msg->spi),
1656                                           GFP_KERNEL | GFP_DMA);
1657         if (ret) {
1658                 msg->status = ret;
1659                 spi_finalize_current_message(ctlr);
1660                 return ret;
1661         }
1662
1663         if (ctlr->prepare_message) {
1664                 ret = ctlr->prepare_message(ctlr, msg);
1665                 if (ret) {
1666                         dev_err(&ctlr->dev, "failed to prepare message: %d\n",
1667                                 ret);
1668                         msg->status = ret;
1669                         spi_finalize_current_message(ctlr);
1670                         return ret;
1671                 }
1672                 msg->prepared = true;
1673         }
1674
1675         ret = spi_map_msg(ctlr, msg);
1676         if (ret) {
1677                 msg->status = ret;
1678                 spi_finalize_current_message(ctlr);
1679                 return ret;
1680         }
1681
1682         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
1683                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
1684                         xfer->ptp_sts_word_pre = 0;
1685                         ptp_read_system_prets(xfer->ptp_sts);
1686                 }
1687         }
1688
1689         /*
1690          * Drivers implementation of transfer_one_message() must arrange for
1691          * spi_finalize_current_message() to get called. Most drivers will do
1692          * this in the calling context, but some don't. For those cases, a
1693          * completion is used to guarantee that this function does not return
1694          * until spi_finalize_current_message() is done accessing
1695          * ctlr->cur_msg.
1696          * Use of the following two flags enable to opportunistically skip the
1697          * use of the completion since its use involves expensive spin locks.
1698          * In case of a race with the context that calls
1699          * spi_finalize_current_message() the completion will always be used,
1700          * due to strict ordering of these flags using barriers.
1701          */
1702         WRITE_ONCE(ctlr->cur_msg_incomplete, true);
1703         WRITE_ONCE(ctlr->cur_msg_need_completion, false);
1704         reinit_completion(&ctlr->cur_msg_completion);
1705         smp_wmb(); /* Make these available to spi_finalize_current_message() */
1706
1707         ret = ctlr->transfer_one_message(ctlr, msg);
1708         if (ret) {
1709                 dev_err(&ctlr->dev,
1710                         "failed to transfer one message from queue\n");
1711                 return ret;
1712         }
1713
1714         WRITE_ONCE(ctlr->cur_msg_need_completion, true);
1715         smp_mb(); /* See spi_finalize_current_message()... */
1716         if (READ_ONCE(ctlr->cur_msg_incomplete))
1717                 wait_for_completion(&ctlr->cur_msg_completion);
1718
1719         return 0;
1720 }
1721
1722 /**
1723  * __spi_pump_messages - function which processes spi message queue
1724  * @ctlr: controller to process queue for
1725  * @in_kthread: true if we are in the context of the message pump thread
1726  *
1727  * This function checks if there is any spi message in the queue that
1728  * needs processing and if so call out to the driver to initialize hardware
1729  * and transfer each message.
1730  *
1731  * Note that it is called both from the kthread itself and also from
1732  * inside spi_sync(); the queue extraction handling at the top of the
1733  * function should deal with this safely.
1734  */
1735 static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
1736 {
1737         struct spi_message *msg;
1738         bool was_busy = false;
1739         unsigned long flags;
1740         int ret;
1741
1742         /* Take the IO mutex */
1743         mutex_lock(&ctlr->io_mutex);
1744
1745         /* Lock queue */
1746         spin_lock_irqsave(&ctlr->queue_lock, flags);
1747
1748         /* Make sure we are not already running a message */
1749         if (ctlr->cur_msg)
1750                 goto out_unlock;
1751
1752         /* Check if the queue is idle */
1753         if (list_empty(&ctlr->queue) || !ctlr->running) {
1754                 if (!ctlr->busy)
1755                         goto out_unlock;
1756
1757                 /* Defer any non-atomic teardown to the thread */
1758                 if (!in_kthread) {
1759                         if (!ctlr->dummy_rx && !ctlr->dummy_tx &&
1760                             !ctlr->unprepare_transfer_hardware) {
1761                                 spi_idle_runtime_pm(ctlr);
1762                                 ctlr->busy = false;
1763                                 ctlr->queue_empty = true;
1764                                 trace_spi_controller_idle(ctlr);
1765                         } else {
1766                                 kthread_queue_work(ctlr->kworker,
1767                                                    &ctlr->pump_messages);
1768                         }
1769                         goto out_unlock;
1770                 }
1771
1772                 ctlr->busy = false;
1773                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1774
1775                 kfree(ctlr->dummy_rx);
1776                 ctlr->dummy_rx = NULL;
1777                 kfree(ctlr->dummy_tx);
1778                 ctlr->dummy_tx = NULL;
1779                 if (ctlr->unprepare_transfer_hardware &&
1780                     ctlr->unprepare_transfer_hardware(ctlr))
1781                         dev_err(&ctlr->dev,
1782                                 "failed to unprepare transfer hardware\n");
1783                 spi_idle_runtime_pm(ctlr);
1784                 trace_spi_controller_idle(ctlr);
1785
1786                 spin_lock_irqsave(&ctlr->queue_lock, flags);
1787                 ctlr->queue_empty = true;
1788                 goto out_unlock;
1789         }
1790
1791         /* Extract head of queue */
1792         msg = list_first_entry(&ctlr->queue, struct spi_message, queue);
1793         ctlr->cur_msg = msg;
1794
1795         list_del_init(&msg->queue);
1796         if (ctlr->busy)
1797                 was_busy = true;
1798         else
1799                 ctlr->busy = true;
1800         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1801
1802         ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
1803         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
1804
1805         ctlr->cur_msg = NULL;
1806         ctlr->fallback = false;
1807
1808         mutex_unlock(&ctlr->io_mutex);
1809
1810         /* Prod the scheduler in case transfer_one() was busy waiting */
1811         if (!ret)
1812                 cond_resched();
1813         return;
1814
1815 out_unlock:
1816         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1817         mutex_unlock(&ctlr->io_mutex);
1818 }
1819
1820 /**
1821  * spi_pump_messages - kthread work function which processes spi message queue
1822  * @work: pointer to kthread work struct contained in the controller struct
1823  */
1824 static void spi_pump_messages(struct kthread_work *work)
1825 {
1826         struct spi_controller *ctlr =
1827                 container_of(work, struct spi_controller, pump_messages);
1828
1829         __spi_pump_messages(ctlr, true);
1830 }
1831
1832 /**
1833  * spi_take_timestamp_pre - helper to collect the beginning of the TX timestamp
1834  * @ctlr: Pointer to the spi_controller structure of the driver
1835  * @xfer: Pointer to the transfer being timestamped
1836  * @progress: How many words (not bytes) have been transferred so far
1837  * @irqs_off: If true, will disable IRQs and preemption for the duration of the
1838  *            transfer, for less jitter in time measurement. Only compatible
1839  *            with PIO drivers. If true, must follow up with
1840  *            spi_take_timestamp_post or otherwise system will crash.
1841  *            WARNING: for fully predictable results, the CPU frequency must
1842  *            also be under control (governor).
1843  *
1844  * This is a helper for drivers to collect the beginning of the TX timestamp
1845  * for the requested byte from the SPI transfer. The frequency with which this
1846  * function must be called (once per word, once for the whole transfer, once
1847  * per batch of words etc) is arbitrary as long as the @tx buffer offset is
1848  * greater than or equal to the requested byte at the time of the call. The
1849  * timestamp is only taken once, at the first such call. It is assumed that
1850  * the driver advances its @tx buffer pointer monotonically.
1851  */
1852 void spi_take_timestamp_pre(struct spi_controller *ctlr,
1853                             struct spi_transfer *xfer,
1854                             size_t progress, bool irqs_off)
1855 {
1856         if (!xfer->ptp_sts)
1857                 return;
1858
1859         if (xfer->timestamped)
1860                 return;
1861
1862         if (progress > xfer->ptp_sts_word_pre)
1863                 return;
1864
1865         /* Capture the resolution of the timestamp */
1866         xfer->ptp_sts_word_pre = progress;
1867
1868         if (irqs_off) {
1869                 local_irq_save(ctlr->irq_flags);
1870                 preempt_disable();
1871         }
1872
1873         ptp_read_system_prets(xfer->ptp_sts);
1874 }
1875 EXPORT_SYMBOL_GPL(spi_take_timestamp_pre);
1876
1877 /**
1878  * spi_take_timestamp_post - helper to collect the end of the TX timestamp
1879  * @ctlr: Pointer to the spi_controller structure of the driver
1880  * @xfer: Pointer to the transfer being timestamped
1881  * @progress: How many words (not bytes) have been transferred so far
1882  * @irqs_off: If true, will re-enable IRQs and preemption for the local CPU.
1883  *
1884  * This is a helper for drivers to collect the end of the TX timestamp for
1885  * the requested byte from the SPI transfer. Can be called with an arbitrary
1886  * frequency: only the first call where @tx exceeds or is equal to the
1887  * requested word will be timestamped.
1888  */
1889 void spi_take_timestamp_post(struct spi_controller *ctlr,
1890                              struct spi_transfer *xfer,
1891                              size_t progress, bool irqs_off)
1892 {
1893         if (!xfer->ptp_sts)
1894                 return;
1895
1896         if (xfer->timestamped)
1897                 return;
1898
1899         if (progress < xfer->ptp_sts_word_post)
1900                 return;
1901
1902         ptp_read_system_postts(xfer->ptp_sts);
1903
1904         if (irqs_off) {
1905                 local_irq_restore(ctlr->irq_flags);
1906                 preempt_enable();
1907         }
1908
1909         /* Capture the resolution of the timestamp */
1910         xfer->ptp_sts_word_post = progress;
1911
1912         xfer->timestamped = true;
1913 }
1914 EXPORT_SYMBOL_GPL(spi_take_timestamp_post);
1915
1916 /**
1917  * spi_set_thread_rt - set the controller to pump at realtime priority
1918  * @ctlr: controller to boost priority of
1919  *
1920  * This can be called because the controller requested realtime priority
1921  * (by setting the ->rt value before calling spi_register_controller()) or
1922  * because a device on the bus said that its transfers needed realtime
1923  * priority.
1924  *
1925  * NOTE: at the moment if any device on a bus says it needs realtime then
1926  * the thread will be at realtime priority for all transfers on that
1927  * controller.  If this eventually becomes a problem we may see if we can
1928  * find a way to boost the priority only temporarily during relevant
1929  * transfers.
1930  */
1931 static void spi_set_thread_rt(struct spi_controller *ctlr)
1932 {
1933         dev_info(&ctlr->dev,
1934                 "will run message pump with realtime priority\n");
1935         sched_set_fifo(ctlr->kworker->task);
1936 }
1937
1938 static int spi_init_queue(struct spi_controller *ctlr)
1939 {
1940         ctlr->running = false;
1941         ctlr->busy = false;
1942         ctlr->queue_empty = true;
1943
1944         ctlr->kworker = kthread_create_worker(0, dev_name(&ctlr->dev));
1945         if (IS_ERR(ctlr->kworker)) {
1946                 dev_err(&ctlr->dev, "failed to create message pump kworker\n");
1947                 return PTR_ERR(ctlr->kworker);
1948         }
1949
1950         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
1951
1952         /*
1953          * Controller config will indicate if this controller should run the
1954          * message pump with high (realtime) priority to reduce the transfer
1955          * latency on the bus by minimising the delay between a transfer
1956          * request and the scheduling of the message pump thread. Without this
1957          * setting the message pump thread will remain at default priority.
1958          */
1959         if (ctlr->rt)
1960                 spi_set_thread_rt(ctlr);
1961
1962         return 0;
1963 }
1964
1965 /**
1966  * spi_get_next_queued_message() - called by driver to check for queued
1967  * messages
1968  * @ctlr: the controller to check for queued messages
1969  *
1970  * If there are more messages in the queue, the next message is returned from
1971  * this call.
1972  *
1973  * Return: the next message in the queue, else NULL if the queue is empty.
1974  */
1975 struct spi_message *spi_get_next_queued_message(struct spi_controller *ctlr)
1976 {
1977         struct spi_message *next;
1978         unsigned long flags;
1979
1980         /* Get a pointer to the next message, if any */
1981         spin_lock_irqsave(&ctlr->queue_lock, flags);
1982         next = list_first_entry_or_null(&ctlr->queue, struct spi_message,
1983                                         queue);
1984         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
1985
1986         return next;
1987 }
1988 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1989
1990 /**
1991  * spi_finalize_current_message() - the current message is complete
1992  * @ctlr: the controller to return the message to
1993  *
1994  * Called by the driver to notify the core that the message in the front of the
1995  * queue is complete and can be removed from the queue.
1996  */
1997 void spi_finalize_current_message(struct spi_controller *ctlr)
1998 {
1999         struct spi_transfer *xfer;
2000         struct spi_message *mesg;
2001         int ret;
2002
2003         mesg = ctlr->cur_msg;
2004
2005         if (!ctlr->ptp_sts_supported && !ctlr->transfer_one) {
2006                 list_for_each_entry(xfer, &mesg->transfers, transfer_list) {
2007                         ptp_read_system_postts(xfer->ptp_sts);
2008                         xfer->ptp_sts_word_post = xfer->len;
2009                 }
2010         }
2011
2012         if (unlikely(ctlr->ptp_sts_supported))
2013                 list_for_each_entry(xfer, &mesg->transfers, transfer_list)
2014                         WARN_ON_ONCE(xfer->ptp_sts && !xfer->timestamped);
2015
2016         spi_unmap_msg(ctlr, mesg);
2017
2018         /*
2019          * In the prepare_messages callback the SPI bus has the opportunity
2020          * to split a transfer to smaller chunks.
2021          *
2022          * Release the split transfers here since spi_map_msg() is done on
2023          * the split transfers.
2024          */
2025         spi_res_release(ctlr, mesg);
2026
2027         if (mesg->prepared && ctlr->unprepare_message) {
2028                 ret = ctlr->unprepare_message(ctlr, mesg);
2029                 if (ret) {
2030                         dev_err(&ctlr->dev, "failed to unprepare message: %d\n",
2031                                 ret);
2032                 }
2033         }
2034
2035         mesg->prepared = false;
2036
2037         WRITE_ONCE(ctlr->cur_msg_incomplete, false);
2038         smp_mb(); /* See __spi_pump_transfer_message()... */
2039         if (READ_ONCE(ctlr->cur_msg_need_completion))
2040                 complete(&ctlr->cur_msg_completion);
2041
2042         trace_spi_message_done(mesg);
2043
2044         mesg->state = NULL;
2045         if (mesg->complete)
2046                 mesg->complete(mesg->context);
2047 }
2048 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
2049
2050 static int spi_start_queue(struct spi_controller *ctlr)
2051 {
2052         unsigned long flags;
2053
2054         spin_lock_irqsave(&ctlr->queue_lock, flags);
2055
2056         if (ctlr->running || ctlr->busy) {
2057                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2058                 return -EBUSY;
2059         }
2060
2061         ctlr->running = true;
2062         ctlr->cur_msg = NULL;
2063         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2064
2065         kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
2066
2067         return 0;
2068 }
2069
2070 static int spi_stop_queue(struct spi_controller *ctlr)
2071 {
2072         unsigned long flags;
2073         unsigned limit = 500;
2074         int ret = 0;
2075
2076         spin_lock_irqsave(&ctlr->queue_lock, flags);
2077
2078         /*
2079          * This is a bit lame, but is optimized for the common execution path.
2080          * A wait_queue on the ctlr->busy could be used, but then the common
2081          * execution path (pump_messages) would be required to call wake_up or
2082          * friends on every SPI message. Do this instead.
2083          */
2084         while ((!list_empty(&ctlr->queue) || ctlr->busy) && limit--) {
2085                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2086                 usleep_range(10000, 11000);
2087                 spin_lock_irqsave(&ctlr->queue_lock, flags);
2088         }
2089
2090         if (!list_empty(&ctlr->queue) || ctlr->busy)
2091                 ret = -EBUSY;
2092         else
2093                 ctlr->running = false;
2094
2095         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2096
2097         if (ret) {
2098                 dev_warn(&ctlr->dev, "could not stop message queue\n");
2099                 return ret;
2100         }
2101         return ret;
2102 }
2103
2104 static int spi_destroy_queue(struct spi_controller *ctlr)
2105 {
2106         int ret;
2107
2108         ret = spi_stop_queue(ctlr);
2109
2110         /*
2111          * kthread_flush_worker will block until all work is done.
2112          * If the reason that stop_queue timed out is that the work will never
2113          * finish, then it does no good to call flush/stop thread, so
2114          * return anyway.
2115          */
2116         if (ret) {
2117                 dev_err(&ctlr->dev, "problem destroying queue\n");
2118                 return ret;
2119         }
2120
2121         kthread_destroy_worker(ctlr->kworker);
2122
2123         return 0;
2124 }
2125
2126 static int __spi_queued_transfer(struct spi_device *spi,
2127                                  struct spi_message *msg,
2128                                  bool need_pump)
2129 {
2130         struct spi_controller *ctlr = spi->controller;
2131         unsigned long flags;
2132
2133         spin_lock_irqsave(&ctlr->queue_lock, flags);
2134
2135         if (!ctlr->running) {
2136                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2137                 return -ESHUTDOWN;
2138         }
2139         msg->actual_length = 0;
2140         msg->status = -EINPROGRESS;
2141
2142         list_add_tail(&msg->queue, &ctlr->queue);
2143         ctlr->queue_empty = false;
2144         if (!ctlr->busy && need_pump)
2145                 kthread_queue_work(ctlr->kworker, &ctlr->pump_messages);
2146
2147         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
2148         return 0;
2149 }
2150
2151 /**
2152  * spi_queued_transfer - transfer function for queued transfers
2153  * @spi: spi device which is requesting transfer
2154  * @msg: spi message which is to handled is queued to driver queue
2155  *
2156  * Return: zero on success, else a negative error code.
2157  */
2158 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
2159 {
2160         return __spi_queued_transfer(spi, msg, true);
2161 }
2162
2163 static int spi_controller_initialize_queue(struct spi_controller *ctlr)
2164 {
2165         int ret;
2166
2167         ctlr->transfer = spi_queued_transfer;
2168         if (!ctlr->transfer_one_message)
2169                 ctlr->transfer_one_message = spi_transfer_one_message;
2170
2171         /* Initialize and start queue */
2172         ret = spi_init_queue(ctlr);
2173         if (ret) {
2174                 dev_err(&ctlr->dev, "problem initializing queue\n");
2175                 goto err_init_queue;
2176         }
2177         ctlr->queued = true;
2178         ret = spi_start_queue(ctlr);
2179         if (ret) {
2180                 dev_err(&ctlr->dev, "problem starting queue\n");
2181                 goto err_start_queue;
2182         }
2183
2184         return 0;
2185
2186 err_start_queue:
2187         spi_destroy_queue(ctlr);
2188 err_init_queue:
2189         return ret;
2190 }
2191
2192 /**
2193  * spi_flush_queue - Send all pending messages in the queue from the callers'
2194  *                   context
2195  * @ctlr: controller to process queue for
2196  *
2197  * This should be used when one wants to ensure all pending messages have been
2198  * sent before doing something. Is used by the spi-mem code to make sure SPI
2199  * memory operations do not preempt regular SPI transfers that have been queued
2200  * before the spi-mem operation.
2201  */
2202 void spi_flush_queue(struct spi_controller *ctlr)
2203 {
2204         if (ctlr->transfer == spi_queued_transfer)
2205                 __spi_pump_messages(ctlr, false);
2206 }
2207
2208 /*-------------------------------------------------------------------------*/
2209
2210 #if defined(CONFIG_OF)
2211 static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
2212                            struct device_node *nc)
2213 {
2214         u32 value;
2215         int rc;
2216
2217         /* Mode (clock phase/polarity/etc.) */
2218         if (of_property_read_bool(nc, "spi-cpha"))
2219                 spi->mode |= SPI_CPHA;
2220         if (of_property_read_bool(nc, "spi-cpol"))
2221                 spi->mode |= SPI_CPOL;
2222         if (of_property_read_bool(nc, "spi-3wire"))
2223                 spi->mode |= SPI_3WIRE;
2224         if (of_property_read_bool(nc, "spi-lsb-first"))
2225                 spi->mode |= SPI_LSB_FIRST;
2226         if (of_property_read_bool(nc, "spi-cs-high"))
2227                 spi->mode |= SPI_CS_HIGH;
2228
2229         /* Device DUAL/QUAD mode */
2230         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
2231                 switch (value) {
2232                 case 0:
2233                         spi->mode |= SPI_NO_TX;
2234                         break;
2235                 case 1:
2236                         break;
2237                 case 2:
2238                         spi->mode |= SPI_TX_DUAL;
2239                         break;
2240                 case 4:
2241                         spi->mode |= SPI_TX_QUAD;
2242                         break;
2243                 case 8:
2244                         spi->mode |= SPI_TX_OCTAL;
2245                         break;
2246                 default:
2247                         dev_warn(&ctlr->dev,
2248                                 "spi-tx-bus-width %d not supported\n",
2249                                 value);
2250                         break;
2251                 }
2252         }
2253
2254         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
2255                 switch (value) {
2256                 case 0:
2257                         spi->mode |= SPI_NO_RX;
2258                         break;
2259                 case 1:
2260                         break;
2261                 case 2:
2262                         spi->mode |= SPI_RX_DUAL;
2263                         break;
2264                 case 4:
2265                         spi->mode |= SPI_RX_QUAD;
2266                         break;
2267                 case 8:
2268                         spi->mode |= SPI_RX_OCTAL;
2269                         break;
2270                 default:
2271                         dev_warn(&ctlr->dev,
2272                                 "spi-rx-bus-width %d not supported\n",
2273                                 value);
2274                         break;
2275                 }
2276         }
2277
2278         if (spi_controller_is_slave(ctlr)) {
2279                 if (!of_node_name_eq(nc, "slave")) {
2280                         dev_err(&ctlr->dev, "%pOF is not called 'slave'\n",
2281                                 nc);
2282                         return -EINVAL;
2283                 }
2284                 return 0;
2285         }
2286
2287         /* Device address */
2288         rc = of_property_read_u32(nc, "reg", &value);
2289         if (rc) {
2290                 dev_err(&ctlr->dev, "%pOF has no valid 'reg' property (%d)\n",
2291                         nc, rc);
2292                 return rc;
2293         }
2294         spi->chip_select = value;
2295
2296         /* Device speed */
2297         if (!of_property_read_u32(nc, "spi-max-frequency", &value))
2298                 spi->max_speed_hz = value;
2299
2300         return 0;
2301 }
2302
2303 static struct spi_device *
2304 of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc)
2305 {
2306         struct spi_device *spi;
2307         int rc;
2308
2309         /* Alloc an spi_device */
2310         spi = spi_alloc_device(ctlr);
2311         if (!spi) {
2312                 dev_err(&ctlr->dev, "spi_device alloc error for %pOF\n", nc);
2313                 rc = -ENOMEM;
2314                 goto err_out;
2315         }
2316
2317         /* Select device driver */
2318         rc = of_modalias_node(nc, spi->modalias,
2319                                 sizeof(spi->modalias));
2320         if (rc < 0) {
2321                 dev_err(&ctlr->dev, "cannot find modalias for %pOF\n", nc);
2322                 goto err_out;
2323         }
2324
2325         rc = of_spi_parse_dt(ctlr, spi, nc);
2326         if (rc)
2327                 goto err_out;
2328
2329         /* Store a pointer to the node in the device structure */
2330         of_node_get(nc);
2331         spi->dev.of_node = nc;
2332         spi->dev.fwnode = of_fwnode_handle(nc);
2333
2334         /* Register the new device */
2335         rc = spi_add_device(spi);
2336         if (rc) {
2337                 dev_err(&ctlr->dev, "spi_device register error %pOF\n", nc);
2338                 goto err_of_node_put;
2339         }
2340
2341         return spi;
2342
2343 err_of_node_put:
2344         of_node_put(nc);
2345 err_out:
2346         spi_dev_put(spi);
2347         return ERR_PTR(rc);
2348 }
2349
2350 /**
2351  * of_register_spi_devices() - Register child devices onto the SPI bus
2352  * @ctlr:       Pointer to spi_controller device
2353  *
2354  * Registers an spi_device for each child node of controller node which
2355  * represents a valid SPI slave.
2356  */
2357 static void of_register_spi_devices(struct spi_controller *ctlr)
2358 {
2359         struct spi_device *spi;
2360         struct device_node *nc;
2361
2362         if (!ctlr->dev.of_node)
2363                 return;
2364
2365         for_each_available_child_of_node(ctlr->dev.of_node, nc) {
2366                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
2367                         continue;
2368                 spi = of_register_spi_device(ctlr, nc);
2369                 if (IS_ERR(spi)) {
2370                         dev_warn(&ctlr->dev,
2371                                  "Failed to create SPI device for %pOF\n", nc);
2372                         of_node_clear_flag(nc, OF_POPULATED);
2373                 }
2374         }
2375 }
2376 #else
2377 static void of_register_spi_devices(struct spi_controller *ctlr) { }
2378 #endif
2379
2380 /**
2381  * spi_new_ancillary_device() - Register ancillary SPI device
2382  * @spi:         Pointer to the main SPI device registering the ancillary device
2383  * @chip_select: Chip Select of the ancillary device
2384  *
2385  * Register an ancillary SPI device; for example some chips have a chip-select
2386  * for normal device usage and another one for setup/firmware upload.
2387  *
2388  * This may only be called from main SPI device's probe routine.
2389  *
2390  * Return: 0 on success; negative errno on failure
2391  */
2392 struct spi_device *spi_new_ancillary_device(struct spi_device *spi,
2393                                              u8 chip_select)
2394 {
2395         struct spi_device *ancillary;
2396         int rc = 0;
2397
2398         /* Alloc an spi_device */
2399         ancillary = spi_alloc_device(spi->controller);
2400         if (!ancillary) {
2401                 rc = -ENOMEM;
2402                 goto err_out;
2403         }
2404
2405         strscpy(ancillary->modalias, "dummy", sizeof(ancillary->modalias));
2406
2407         /* Use provided chip-select for ancillary device */
2408         ancillary->chip_select = chip_select;
2409
2410         /* Take over SPI mode/speed from SPI main device */
2411         ancillary->max_speed_hz = spi->max_speed_hz;
2412         ancillary->mode = spi->mode;
2413
2414         /* Register the new device */
2415         rc = spi_add_device_locked(ancillary);
2416         if (rc) {
2417                 dev_err(&spi->dev, "failed to register ancillary device\n");
2418                 goto err_out;
2419         }
2420
2421         return ancillary;
2422
2423 err_out:
2424         spi_dev_put(ancillary);
2425         return ERR_PTR(rc);
2426 }
2427 EXPORT_SYMBOL_GPL(spi_new_ancillary_device);
2428
2429 #ifdef CONFIG_ACPI
2430 struct acpi_spi_lookup {
2431         struct spi_controller   *ctlr;
2432         u32                     max_speed_hz;
2433         u32                     mode;
2434         int                     irq;
2435         u8                      bits_per_word;
2436         u8                      chip_select;
2437         int                     n;
2438         int                     index;
2439 };
2440
2441 static int acpi_spi_count(struct acpi_resource *ares, void *data)
2442 {
2443         struct acpi_resource_spi_serialbus *sb;
2444         int *count = data;
2445
2446         if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
2447                 return 1;
2448
2449         sb = &ares->data.spi_serial_bus;
2450         if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_SPI)
2451                 return 1;
2452
2453         *count = *count + 1;
2454
2455         return 1;
2456 }
2457
2458 /**
2459  * acpi_spi_count_resources - Count the number of SpiSerialBus resources
2460  * @adev:       ACPI device
2461  *
2462  * Returns the number of SpiSerialBus resources in the ACPI-device's
2463  * resource-list; or a negative error code.
2464  */
2465 int acpi_spi_count_resources(struct acpi_device *adev)
2466 {
2467         LIST_HEAD(r);
2468         int count = 0;
2469         int ret;
2470
2471         ret = acpi_dev_get_resources(adev, &r, acpi_spi_count, &count);
2472         if (ret < 0)
2473                 return ret;
2474
2475         acpi_dev_free_resource_list(&r);
2476
2477         return count;
2478 }
2479 EXPORT_SYMBOL_GPL(acpi_spi_count_resources);
2480
2481 static void acpi_spi_parse_apple_properties(struct acpi_device *dev,
2482                                             struct acpi_spi_lookup *lookup)
2483 {
2484         const union acpi_object *obj;
2485
2486         if (!x86_apple_machine)
2487                 return;
2488
2489         if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj)
2490             && obj->buffer.length >= 4)
2491                 lookup->max_speed_hz  = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer;
2492
2493         if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj)
2494             && obj->buffer.length == 8)
2495                 lookup->bits_per_word = *(u64 *)obj->buffer.pointer;
2496
2497         if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj)
2498             && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer)
2499                 lookup->mode |= SPI_LSB_FIRST;
2500
2501         if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj)
2502             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2503                 lookup->mode |= SPI_CPOL;
2504
2505         if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj)
2506             && obj->buffer.length == 8 &&  *(u64 *)obj->buffer.pointer)
2507                 lookup->mode |= SPI_CPHA;
2508 }
2509
2510 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev);
2511
2512 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
2513 {
2514         struct acpi_spi_lookup *lookup = data;
2515         struct spi_controller *ctlr = lookup->ctlr;
2516
2517         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
2518                 struct acpi_resource_spi_serialbus *sb;
2519                 acpi_handle parent_handle;
2520                 acpi_status status;
2521
2522                 sb = &ares->data.spi_serial_bus;
2523                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
2524
2525                         if (lookup->index != -1 && lookup->n++ != lookup->index)
2526                                 return 1;
2527
2528                         status = acpi_get_handle(NULL,
2529                                                  sb->resource_source.string_ptr,
2530                                                  &parent_handle);
2531
2532                         if (ACPI_FAILURE(status))
2533                                 return -ENODEV;
2534
2535                         if (ctlr) {
2536                                 if (ACPI_HANDLE(ctlr->dev.parent) != parent_handle)
2537                                         return -ENODEV;
2538                         } else {
2539                                 struct acpi_device *adev;
2540
2541                                 adev = acpi_fetch_acpi_dev(parent_handle);
2542                                 if (!adev)
2543                                         return -ENODEV;
2544
2545                                 ctlr = acpi_spi_find_controller_by_adev(adev);
2546                                 if (!ctlr)
2547                                         return -EPROBE_DEFER;
2548
2549                                 lookup->ctlr = ctlr;
2550                         }
2551
2552                         /*
2553                          * ACPI DeviceSelection numbering is handled by the
2554                          * host controller driver in Windows and can vary
2555                          * from driver to driver. In Linux we always expect
2556                          * 0 .. max - 1 so we need to ask the driver to
2557                          * translate between the two schemes.
2558                          */
2559                         if (ctlr->fw_translate_cs) {
2560                                 int cs = ctlr->fw_translate_cs(ctlr,
2561                                                 sb->device_selection);
2562                                 if (cs < 0)
2563                                         return cs;
2564                                 lookup->chip_select = cs;
2565                         } else {
2566                                 lookup->chip_select = sb->device_selection;
2567                         }
2568
2569                         lookup->max_speed_hz = sb->connection_speed;
2570                         lookup->bits_per_word = sb->data_bit_length;
2571
2572                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
2573                                 lookup->mode |= SPI_CPHA;
2574                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
2575                                 lookup->mode |= SPI_CPOL;
2576                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
2577                                 lookup->mode |= SPI_CS_HIGH;
2578                 }
2579         } else if (lookup->irq < 0) {
2580                 struct resource r;
2581
2582                 if (acpi_dev_resource_interrupt(ares, 0, &r))
2583                         lookup->irq = r.start;
2584         }
2585
2586         /* Always tell the ACPI core to skip this resource */
2587         return 1;
2588 }
2589
2590 /**
2591  * acpi_spi_device_alloc - Allocate a spi device, and fill it in with ACPI information
2592  * @ctlr: controller to which the spi device belongs
2593  * @adev: ACPI Device for the spi device
2594  * @index: Index of the spi resource inside the ACPI Node
2595  *
2596  * This should be used to allocate a new spi device from and ACPI Node.
2597  * The caller is responsible for calling spi_add_device to register the spi device.
2598  *
2599  * If ctlr is set to NULL, the Controller for the spi device will be looked up
2600  * using the resource.
2601  * If index is set to -1, index is not used.
2602  * Note: If index is -1, ctlr must be set.
2603  *
2604  * Return: a pointer to the new device, or ERR_PTR on error.
2605  */
2606 struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
2607                                          struct acpi_device *adev,
2608                                          int index)
2609 {
2610         acpi_handle parent_handle = NULL;
2611         struct list_head resource_list;
2612         struct acpi_spi_lookup lookup = {};
2613         struct spi_device *spi;
2614         int ret;
2615
2616         if (!ctlr && index == -1)
2617                 return ERR_PTR(-EINVAL);
2618
2619         lookup.ctlr             = ctlr;
2620         lookup.irq              = -1;
2621         lookup.index            = index;
2622         lookup.n                = 0;
2623
2624         INIT_LIST_HEAD(&resource_list);
2625         ret = acpi_dev_get_resources(adev, &resource_list,
2626                                      acpi_spi_add_resource, &lookup);
2627         acpi_dev_free_resource_list(&resource_list);
2628
2629         if (ret < 0)
2630                 /* Found SPI in _CRS but it points to another controller */
2631                 return ERR_PTR(ret);
2632
2633         if (!lookup.max_speed_hz &&
2634             ACPI_SUCCESS(acpi_get_parent(adev->handle, &parent_handle)) &&
2635             ACPI_HANDLE(lookup.ctlr->dev.parent) == parent_handle) {
2636                 /* Apple does not use _CRS but nested devices for SPI slaves */
2637                 acpi_spi_parse_apple_properties(adev, &lookup);
2638         }
2639
2640         if (!lookup.max_speed_hz)
2641                 return ERR_PTR(-ENODEV);
2642
2643         spi = spi_alloc_device(lookup.ctlr);
2644         if (!spi) {
2645                 dev_err(&lookup.ctlr->dev, "failed to allocate SPI device for %s\n",
2646                         dev_name(&adev->dev));
2647                 return ERR_PTR(-ENOMEM);
2648         }
2649
2650         ACPI_COMPANION_SET(&spi->dev, adev);
2651         spi->max_speed_hz       = lookup.max_speed_hz;
2652         spi->mode               |= lookup.mode;
2653         spi->irq                = lookup.irq;
2654         spi->bits_per_word      = lookup.bits_per_word;
2655         spi->chip_select        = lookup.chip_select;
2656
2657         return spi;
2658 }
2659 EXPORT_SYMBOL_GPL(acpi_spi_device_alloc);
2660
2661 static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
2662                                             struct acpi_device *adev)
2663 {
2664         struct spi_device *spi;
2665
2666         if (acpi_bus_get_status(adev) || !adev->status.present ||
2667             acpi_device_enumerated(adev))
2668                 return AE_OK;
2669
2670         spi = acpi_spi_device_alloc(ctlr, adev, -1);
2671         if (IS_ERR(spi)) {
2672                 if (PTR_ERR(spi) == -ENOMEM)
2673                         return AE_NO_MEMORY;
2674                 else
2675                         return AE_OK;
2676         }
2677
2678         acpi_set_modalias(adev, acpi_device_hid(adev), spi->modalias,
2679                           sizeof(spi->modalias));
2680
2681         if (spi->irq < 0)
2682                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
2683
2684         acpi_device_set_enumerated(adev);
2685
2686         adev->power.flags.ignore_parent = true;
2687         if (spi_add_device(spi)) {
2688                 adev->power.flags.ignore_parent = false;
2689                 dev_err(&ctlr->dev, "failed to add SPI device %s from ACPI\n",
2690                         dev_name(&adev->dev));
2691                 spi_dev_put(spi);
2692         }
2693
2694         return AE_OK;
2695 }
2696
2697 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
2698                                        void *data, void **return_value)
2699 {
2700         struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
2701         struct spi_controller *ctlr = data;
2702
2703         if (!adev)
2704                 return AE_OK;
2705
2706         return acpi_register_spi_device(ctlr, adev);
2707 }
2708
2709 #define SPI_ACPI_ENUMERATE_MAX_DEPTH            32
2710
2711 static void acpi_register_spi_devices(struct spi_controller *ctlr)
2712 {
2713         acpi_status status;
2714         acpi_handle handle;
2715
2716         handle = ACPI_HANDLE(ctlr->dev.parent);
2717         if (!handle)
2718                 return;
2719
2720         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
2721                                      SPI_ACPI_ENUMERATE_MAX_DEPTH,
2722                                      acpi_spi_add_device, NULL, ctlr, NULL);
2723         if (ACPI_FAILURE(status))
2724                 dev_warn(&ctlr->dev, "failed to enumerate SPI slaves\n");
2725 }
2726 #else
2727 static inline void acpi_register_spi_devices(struct spi_controller *ctlr) {}
2728 #endif /* CONFIG_ACPI */
2729
2730 static void spi_controller_release(struct device *dev)
2731 {
2732         struct spi_controller *ctlr;
2733
2734         ctlr = container_of(dev, struct spi_controller, dev);
2735         kfree(ctlr);
2736 }
2737
2738 static struct class spi_master_class = {
2739         .name           = "spi_master",
2740         .owner          = THIS_MODULE,
2741         .dev_release    = spi_controller_release,
2742         .dev_groups     = spi_master_groups,
2743 };
2744
2745 #ifdef CONFIG_SPI_SLAVE
2746 /**
2747  * spi_slave_abort - abort the ongoing transfer request on an SPI slave
2748  *                   controller
2749  * @spi: device used for the current transfer
2750  */
2751 int spi_slave_abort(struct spi_device *spi)
2752 {
2753         struct spi_controller *ctlr = spi->controller;
2754
2755         if (spi_controller_is_slave(ctlr) && ctlr->slave_abort)
2756                 return ctlr->slave_abort(ctlr);
2757
2758         return -ENOTSUPP;
2759 }
2760 EXPORT_SYMBOL_GPL(spi_slave_abort);
2761
2762 static ssize_t slave_show(struct device *dev, struct device_attribute *attr,
2763                           char *buf)
2764 {
2765         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2766                                                    dev);
2767         struct device *child;
2768
2769         child = device_find_any_child(&ctlr->dev);
2770         return sprintf(buf, "%s\n",
2771                        child ? to_spi_device(child)->modalias : NULL);
2772 }
2773
2774 static ssize_t slave_store(struct device *dev, struct device_attribute *attr,
2775                            const char *buf, size_t count)
2776 {
2777         struct spi_controller *ctlr = container_of(dev, struct spi_controller,
2778                                                    dev);
2779         struct spi_device *spi;
2780         struct device *child;
2781         char name[32];
2782         int rc;
2783
2784         rc = sscanf(buf, "%31s", name);
2785         if (rc != 1 || !name[0])
2786                 return -EINVAL;
2787
2788         child = device_find_any_child(&ctlr->dev);
2789         if (child) {
2790                 /* Remove registered slave */
2791                 device_unregister(child);
2792                 put_device(child);
2793         }
2794
2795         if (strcmp(name, "(null)")) {
2796                 /* Register new slave */
2797                 spi = spi_alloc_device(ctlr);
2798                 if (!spi)
2799                         return -ENOMEM;
2800
2801                 strscpy(spi->modalias, name, sizeof(spi->modalias));
2802
2803                 rc = spi_add_device(spi);
2804                 if (rc) {
2805                         spi_dev_put(spi);
2806                         return rc;
2807                 }
2808         }
2809
2810         return count;
2811 }
2812
2813 static DEVICE_ATTR_RW(slave);
2814
2815 static struct attribute *spi_slave_attrs[] = {
2816         &dev_attr_slave.attr,
2817         NULL,
2818 };
2819
2820 static const struct attribute_group spi_slave_group = {
2821         .attrs = spi_slave_attrs,
2822 };
2823
2824 static const struct attribute_group *spi_slave_groups[] = {
2825         &spi_controller_statistics_group,
2826         &spi_slave_group,
2827         NULL,
2828 };
2829
2830 static struct class spi_slave_class = {
2831         .name           = "spi_slave",
2832         .owner          = THIS_MODULE,
2833         .dev_release    = spi_controller_release,
2834         .dev_groups     = spi_slave_groups,
2835 };
2836 #else
2837 extern struct class spi_slave_class;    /* dummy */
2838 #endif
2839
2840 /**
2841  * __spi_alloc_controller - allocate an SPI master or slave controller
2842  * @dev: the controller, possibly using the platform_bus
2843  * @size: how much zeroed driver-private data to allocate; the pointer to this
2844  *      memory is in the driver_data field of the returned device, accessible
2845  *      with spi_controller_get_devdata(); the memory is cacheline aligned;
2846  *      drivers granting DMA access to portions of their private data need to
2847  *      round up @size using ALIGN(size, dma_get_cache_alignment()).
2848  * @slave: flag indicating whether to allocate an SPI master (false) or SPI
2849  *      slave (true) controller
2850  * Context: can sleep
2851  *
2852  * This call is used only by SPI controller drivers, which are the
2853  * only ones directly touching chip registers.  It's how they allocate
2854  * an spi_controller structure, prior to calling spi_register_controller().
2855  *
2856  * This must be called from context that can sleep.
2857  *
2858  * The caller is responsible for assigning the bus number and initializing the
2859  * controller's methods before calling spi_register_controller(); and (after
2860  * errors adding the device) calling spi_controller_put() to prevent a memory
2861  * leak.
2862  *
2863  * Return: the SPI controller structure on success, else NULL.
2864  */
2865 struct spi_controller *__spi_alloc_controller(struct device *dev,
2866                                               unsigned int size, bool slave)
2867 {
2868         struct spi_controller   *ctlr;
2869         size_t ctlr_size = ALIGN(sizeof(*ctlr), dma_get_cache_alignment());
2870
2871         if (!dev)
2872                 return NULL;
2873
2874         ctlr = kzalloc(size + ctlr_size, GFP_KERNEL);
2875         if (!ctlr)
2876                 return NULL;
2877
2878         device_initialize(&ctlr->dev);
2879         INIT_LIST_HEAD(&ctlr->queue);
2880         spin_lock_init(&ctlr->queue_lock);
2881         spin_lock_init(&ctlr->bus_lock_spinlock);
2882         mutex_init(&ctlr->bus_lock_mutex);
2883         mutex_init(&ctlr->io_mutex);
2884         mutex_init(&ctlr->add_lock);
2885         ctlr->bus_num = -1;
2886         ctlr->num_chipselect = 1;
2887         ctlr->slave = slave;
2888         if (IS_ENABLED(CONFIG_SPI_SLAVE) && slave)
2889                 ctlr->dev.class = &spi_slave_class;
2890         else
2891                 ctlr->dev.class = &spi_master_class;
2892         ctlr->dev.parent = dev;
2893         pm_suspend_ignore_children(&ctlr->dev, true);
2894         spi_controller_set_devdata(ctlr, (void *)ctlr + ctlr_size);
2895
2896         return ctlr;
2897 }
2898 EXPORT_SYMBOL_GPL(__spi_alloc_controller);
2899
2900 static void devm_spi_release_controller(struct device *dev, void *ctlr)
2901 {
2902         spi_controller_put(*(struct spi_controller **)ctlr);
2903 }
2904
2905 /**
2906  * __devm_spi_alloc_controller - resource-managed __spi_alloc_controller()
2907  * @dev: physical device of SPI controller
2908  * @size: how much zeroed driver-private data to allocate
2909  * @slave: whether to allocate an SPI master (false) or SPI slave (true)
2910  * Context: can sleep
2911  *
2912  * Allocate an SPI controller and automatically release a reference on it
2913  * when @dev is unbound from its driver.  Drivers are thus relieved from
2914  * having to call spi_controller_put().
2915  *
2916  * The arguments to this function are identical to __spi_alloc_controller().
2917  *
2918  * Return: the SPI controller structure on success, else NULL.
2919  */
2920 struct spi_controller *__devm_spi_alloc_controller(struct device *dev,
2921                                                    unsigned int size,
2922                                                    bool slave)
2923 {
2924         struct spi_controller **ptr, *ctlr;
2925
2926         ptr = devres_alloc(devm_spi_release_controller, sizeof(*ptr),
2927                            GFP_KERNEL);
2928         if (!ptr)
2929                 return NULL;
2930
2931         ctlr = __spi_alloc_controller(dev, size, slave);
2932         if (ctlr) {
2933                 ctlr->devm_allocated = true;
2934                 *ptr = ctlr;
2935                 devres_add(dev, ptr);
2936         } else {
2937                 devres_free(ptr);
2938         }
2939
2940         return ctlr;
2941 }
2942 EXPORT_SYMBOL_GPL(__devm_spi_alloc_controller);
2943
2944 /**
2945  * spi_get_gpio_descs() - grab chip select GPIOs for the master
2946  * @ctlr: The SPI master to grab GPIO descriptors for
2947  */
2948 static int spi_get_gpio_descs(struct spi_controller *ctlr)
2949 {
2950         int nb, i;
2951         struct gpio_desc **cs;
2952         struct device *dev = &ctlr->dev;
2953         unsigned long native_cs_mask = 0;
2954         unsigned int num_cs_gpios = 0;
2955
2956         nb = gpiod_count(dev, "cs");
2957         if (nb < 0) {
2958                 /* No GPIOs at all is fine, else return the error */
2959                 if (nb == -ENOENT)
2960                         return 0;
2961                 return nb;
2962         }
2963
2964         ctlr->num_chipselect = max_t(int, nb, ctlr->num_chipselect);
2965
2966         cs = devm_kcalloc(dev, ctlr->num_chipselect, sizeof(*cs),
2967                           GFP_KERNEL);
2968         if (!cs)
2969                 return -ENOMEM;
2970         ctlr->cs_gpiods = cs;
2971
2972         for (i = 0; i < nb; i++) {
2973                 /*
2974                  * Most chipselects are active low, the inverted
2975                  * semantics are handled by special quirks in gpiolib,
2976                  * so initializing them GPIOD_OUT_LOW here means
2977                  * "unasserted", in most cases this will drive the physical
2978                  * line high.
2979                  */
2980                 cs[i] = devm_gpiod_get_index_optional(dev, "cs", i,
2981                                                       GPIOD_OUT_LOW);
2982                 if (IS_ERR(cs[i]))
2983                         return PTR_ERR(cs[i]);
2984
2985                 if (cs[i]) {
2986                         /*
2987                          * If we find a CS GPIO, name it after the device and
2988                          * chip select line.
2989                          */
2990                         char *gpioname;
2991
2992                         gpioname = devm_kasprintf(dev, GFP_KERNEL, "%s CS%d",
2993                                                   dev_name(dev), i);
2994                         if (!gpioname)
2995                                 return -ENOMEM;
2996                         gpiod_set_consumer_name(cs[i], gpioname);
2997                         num_cs_gpios++;
2998                         continue;
2999                 }
3000
3001                 if (ctlr->max_native_cs && i >= ctlr->max_native_cs) {
3002                         dev_err(dev, "Invalid native chip select %d\n", i);
3003                         return -EINVAL;
3004                 }
3005                 native_cs_mask |= BIT(i);
3006         }
3007
3008         ctlr->unused_native_cs = ffs(~native_cs_mask) - 1;
3009
3010         if ((ctlr->flags & SPI_MASTER_GPIO_SS) && num_cs_gpios &&
3011             ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) {
3012                 dev_err(dev, "No unused native chip select available\n");
3013                 return -EINVAL;
3014         }
3015
3016         return 0;
3017 }
3018
3019 static int spi_controller_check_ops(struct spi_controller *ctlr)
3020 {
3021         /*
3022          * The controller may implement only the high-level SPI-memory like
3023          * operations if it does not support regular SPI transfers, and this is
3024          * valid use case.
3025          * If ->mem_ops is NULL, we request that at least one of the
3026          * ->transfer_xxx() method be implemented.
3027          */
3028         if (ctlr->mem_ops) {
3029                 if (!ctlr->mem_ops->exec_op)
3030                         return -EINVAL;
3031         } else if (!ctlr->transfer && !ctlr->transfer_one &&
3032                    !ctlr->transfer_one_message) {
3033                 return -EINVAL;
3034         }
3035
3036         return 0;
3037 }
3038
3039 /**
3040  * spi_register_controller - register SPI master or slave controller
3041  * @ctlr: initialized master, originally from spi_alloc_master() or
3042  *      spi_alloc_slave()
3043  * Context: can sleep
3044  *
3045  * SPI controllers connect to their drivers using some non-SPI bus,
3046  * such as the platform bus.  The final stage of probe() in that code
3047  * includes calling spi_register_controller() to hook up to this SPI bus glue.
3048  *
3049  * SPI controllers use board specific (often SOC specific) bus numbers,
3050  * and board-specific addressing for SPI devices combines those numbers
3051  * with chip select numbers.  Since SPI does not directly support dynamic
3052  * device identification, boards need configuration tables telling which
3053  * chip is at which address.
3054  *
3055  * This must be called from context that can sleep.  It returns zero on
3056  * success, else a negative error code (dropping the controller's refcount).
3057  * After a successful return, the caller is responsible for calling
3058  * spi_unregister_controller().
3059  *
3060  * Return: zero on success, else a negative error code.
3061  */
3062 int spi_register_controller(struct spi_controller *ctlr)
3063 {
3064         struct device           *dev = ctlr->dev.parent;
3065         struct boardinfo        *bi;
3066         int                     status;
3067         int                     id, first_dynamic;
3068
3069         if (!dev)
3070                 return -ENODEV;
3071
3072         /*
3073          * Make sure all necessary hooks are implemented before registering
3074          * the SPI controller.
3075          */
3076         status = spi_controller_check_ops(ctlr);
3077         if (status)
3078                 return status;
3079
3080         if (ctlr->bus_num >= 0) {
3081                 /* Devices with a fixed bus num must check-in with the num */
3082                 mutex_lock(&board_lock);
3083                 id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
3084                         ctlr->bus_num + 1, GFP_KERNEL);
3085                 mutex_unlock(&board_lock);
3086                 if (WARN(id < 0, "couldn't get idr"))
3087                         return id == -ENOSPC ? -EBUSY : id;
3088                 ctlr->bus_num = id;
3089         } else if (ctlr->dev.of_node) {
3090                 /* Allocate dynamic bus number using Linux idr */
3091                 id = of_alias_get_id(ctlr->dev.of_node, "spi");
3092                 if (id >= 0) {
3093                         ctlr->bus_num = id;
3094                         mutex_lock(&board_lock);
3095                         id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,
3096                                        ctlr->bus_num + 1, GFP_KERNEL);
3097                         mutex_unlock(&board_lock);
3098                         if (WARN(id < 0, "couldn't get idr"))
3099                                 return id == -ENOSPC ? -EBUSY : id;
3100                 }
3101         }
3102         if (ctlr->bus_num < 0) {
3103                 first_dynamic = of_alias_get_highest_id("spi");
3104                 if (first_dynamic < 0)
3105                         first_dynamic = 0;
3106                 else
3107                         first_dynamic++;
3108
3109                 mutex_lock(&board_lock);
3110                 id = idr_alloc(&spi_master_idr, ctlr, first_dynamic,
3111                                0, GFP_KERNEL);
3112                 mutex_unlock(&board_lock);
3113                 if (WARN(id < 0, "couldn't get idr"))
3114                         return id;
3115                 ctlr->bus_num = id;
3116         }
3117         ctlr->bus_lock_flag = 0;
3118         init_completion(&ctlr->xfer_completion);
3119         init_completion(&ctlr->cur_msg_completion);
3120         if (!ctlr->max_dma_len)
3121                 ctlr->max_dma_len = INT_MAX;
3122
3123         /*
3124          * Register the device, then userspace will see it.
3125          * Registration fails if the bus ID is in use.
3126          */
3127         dev_set_name(&ctlr->dev, "spi%u", ctlr->bus_num);
3128
3129         if (!spi_controller_is_slave(ctlr) && ctlr->use_gpio_descriptors) {
3130                 status = spi_get_gpio_descs(ctlr);
3131                 if (status)
3132                         goto free_bus_id;
3133                 /*
3134                  * A controller using GPIO descriptors always
3135                  * supports SPI_CS_HIGH if need be.
3136                  */
3137                 ctlr->mode_bits |= SPI_CS_HIGH;
3138         }
3139
3140         /*
3141          * Even if it's just one always-selected device, there must
3142          * be at least one chipselect.
3143          */
3144         if (!ctlr->num_chipselect) {
3145                 status = -EINVAL;
3146                 goto free_bus_id;
3147         }
3148
3149         /* Setting last_cs to -1 means no chip selected */
3150         ctlr->last_cs = -1;
3151
3152         status = device_add(&ctlr->dev);
3153         if (status < 0)
3154                 goto free_bus_id;
3155         dev_dbg(dev, "registered %s %s\n",
3156                         spi_controller_is_slave(ctlr) ? "slave" : "master",
3157                         dev_name(&ctlr->dev));
3158
3159         /*
3160          * If we're using a queued driver, start the queue. Note that we don't
3161          * need the queueing logic if the driver is only supporting high-level
3162          * memory operations.
3163          */
3164         if (ctlr->transfer) {
3165                 dev_info(dev, "controller is unqueued, this is deprecated\n");
3166         } else if (ctlr->transfer_one || ctlr->transfer_one_message) {
3167                 status = spi_controller_initialize_queue(ctlr);
3168                 if (status) {
3169                         device_del(&ctlr->dev);
3170                         goto free_bus_id;
3171                 }
3172         }
3173         /* Add statistics */
3174         ctlr->pcpu_statistics = spi_alloc_pcpu_stats(dev);
3175         if (!ctlr->pcpu_statistics) {
3176                 dev_err(dev, "Error allocating per-cpu statistics\n");
3177                 status = -ENOMEM;
3178                 goto destroy_queue;
3179         }
3180
3181         mutex_lock(&board_lock);
3182         list_add_tail(&ctlr->list, &spi_controller_list);
3183         list_for_each_entry(bi, &board_list, list)
3184                 spi_match_controller_to_boardinfo(ctlr, &bi->board_info);
3185         mutex_unlock(&board_lock);
3186
3187         /* Register devices from the device tree and ACPI */
3188         of_register_spi_devices(ctlr);
3189         acpi_register_spi_devices(ctlr);
3190         return status;
3191
3192 destroy_queue:
3193         spi_destroy_queue(ctlr);
3194 free_bus_id:
3195         mutex_lock(&board_lock);
3196         idr_remove(&spi_master_idr, ctlr->bus_num);
3197         mutex_unlock(&board_lock);
3198         return status;
3199 }
3200 EXPORT_SYMBOL_GPL(spi_register_controller);
3201
3202 static void devm_spi_unregister(struct device *dev, void *res)
3203 {
3204         spi_unregister_controller(*(struct spi_controller **)res);
3205 }
3206
3207 /**
3208  * devm_spi_register_controller - register managed SPI master or slave
3209  *      controller
3210  * @dev:    device managing SPI controller
3211  * @ctlr: initialized controller, originally from spi_alloc_master() or
3212  *      spi_alloc_slave()
3213  * Context: can sleep
3214  *
3215  * Register a SPI device as with spi_register_controller() which will
3216  * automatically be unregistered and freed.
3217  *
3218  * Return: zero on success, else a negative error code.
3219  */
3220 int devm_spi_register_controller(struct device *dev,
3221                                  struct spi_controller *ctlr)
3222 {
3223         struct spi_controller **ptr;
3224         int ret;
3225
3226         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
3227         if (!ptr)
3228                 return -ENOMEM;
3229
3230         ret = spi_register_controller(ctlr);
3231         if (!ret) {
3232                 *ptr = ctlr;
3233                 devres_add(dev, ptr);
3234         } else {
3235                 devres_free(ptr);
3236         }
3237
3238         return ret;
3239 }
3240 EXPORT_SYMBOL_GPL(devm_spi_register_controller);
3241
3242 static int __unregister(struct device *dev, void *null)
3243 {
3244         spi_unregister_device(to_spi_device(dev));
3245         return 0;
3246 }
3247
3248 /**
3249  * spi_unregister_controller - unregister SPI master or slave controller
3250  * @ctlr: the controller being unregistered
3251  * Context: can sleep
3252  *
3253  * This call is used only by SPI controller drivers, which are the
3254  * only ones directly touching chip registers.
3255  *
3256  * This must be called from context that can sleep.
3257  *
3258  * Note that this function also drops a reference to the controller.
3259  */
3260 void spi_unregister_controller(struct spi_controller *ctlr)
3261 {
3262         struct spi_controller *found;
3263         int id = ctlr->bus_num;
3264
3265         /* Prevent addition of new devices, unregister existing ones */
3266         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3267                 mutex_lock(&ctlr->add_lock);
3268
3269         device_for_each_child(&ctlr->dev, NULL, __unregister);
3270
3271         /* First make sure that this controller was ever added */
3272         mutex_lock(&board_lock);
3273         found = idr_find(&spi_master_idr, id);
3274         mutex_unlock(&board_lock);
3275         if (ctlr->queued) {
3276                 if (spi_destroy_queue(ctlr))
3277                         dev_err(&ctlr->dev, "queue remove failed\n");
3278         }
3279         mutex_lock(&board_lock);
3280         list_del(&ctlr->list);
3281         mutex_unlock(&board_lock);
3282
3283         device_del(&ctlr->dev);
3284
3285         /* Free bus id */
3286         mutex_lock(&board_lock);
3287         if (found == ctlr)
3288                 idr_remove(&spi_master_idr, id);
3289         mutex_unlock(&board_lock);
3290
3291         if (IS_ENABLED(CONFIG_SPI_DYNAMIC))
3292                 mutex_unlock(&ctlr->add_lock);
3293
3294         /* Release the last reference on the controller if its driver
3295          * has not yet been converted to devm_spi_alloc_master/slave().
3296          */
3297         if (!ctlr->devm_allocated)
3298                 put_device(&ctlr->dev);
3299 }
3300 EXPORT_SYMBOL_GPL(spi_unregister_controller);
3301
3302 int spi_controller_suspend(struct spi_controller *ctlr)
3303 {
3304         int ret;
3305
3306         /* Basically no-ops for non-queued controllers */
3307         if (!ctlr->queued)
3308                 return 0;
3309
3310         ret = spi_stop_queue(ctlr);
3311         if (ret)
3312                 dev_err(&ctlr->dev, "queue stop failed\n");
3313
3314         return ret;
3315 }
3316 EXPORT_SYMBOL_GPL(spi_controller_suspend);
3317
3318 int spi_controller_resume(struct spi_controller *ctlr)
3319 {
3320         int ret;
3321
3322         if (!ctlr->queued)
3323                 return 0;
3324
3325         ret = spi_start_queue(ctlr);
3326         if (ret)
3327                 dev_err(&ctlr->dev, "queue restart failed\n");
3328
3329         return ret;
3330 }
3331 EXPORT_SYMBOL_GPL(spi_controller_resume);
3332
3333 /*-------------------------------------------------------------------------*/
3334
3335 /* Core methods for spi_message alterations */
3336
3337 static void __spi_replace_transfers_release(struct spi_controller *ctlr,
3338                                             struct spi_message *msg,
3339                                             void *res)
3340 {
3341         struct spi_replaced_transfers *rxfer = res;
3342         size_t i;
3343
3344         /* Call extra callback if requested */
3345         if (rxfer->release)
3346                 rxfer->release(ctlr, msg, res);
3347
3348         /* Insert replaced transfers back into the message */
3349         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
3350
3351         /* Remove the formerly inserted entries */
3352         for (i = 0; i < rxfer->inserted; i++)
3353                 list_del(&rxfer->inserted_transfers[i].transfer_list);
3354 }
3355
3356 /**
3357  * spi_replace_transfers - replace transfers with several transfers
3358  *                         and register change with spi_message.resources
3359  * @msg:           the spi_message we work upon
3360  * @xfer_first:    the first spi_transfer we want to replace
3361  * @remove:        number of transfers to remove
3362  * @insert:        the number of transfers we want to insert instead
3363  * @release:       extra release code necessary in some circumstances
3364  * @extradatasize: extra data to allocate (with alignment guarantees
3365  *                 of struct @spi_transfer)
3366  * @gfp:           gfp flags
3367  *
3368  * Returns: pointer to @spi_replaced_transfers,
3369  *          PTR_ERR(...) in case of errors.
3370  */
3371 static struct spi_replaced_transfers *spi_replace_transfers(
3372         struct spi_message *msg,
3373         struct spi_transfer *xfer_first,
3374         size_t remove,
3375         size_t insert,
3376         spi_replaced_release_t release,
3377         size_t extradatasize,
3378         gfp_t gfp)
3379 {
3380         struct spi_replaced_transfers *rxfer;
3381         struct spi_transfer *xfer;
3382         size_t i;
3383
3384         /* Allocate the structure using spi_res */
3385         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
3386                               struct_size(rxfer, inserted_transfers, insert)
3387                               + extradatasize,
3388                               gfp);
3389         if (!rxfer)
3390                 return ERR_PTR(-ENOMEM);
3391
3392         /* The release code to invoke before running the generic release */
3393         rxfer->release = release;
3394
3395         /* Assign extradata */
3396         if (extradatasize)
3397                 rxfer->extradata =
3398                         &rxfer->inserted_transfers[insert];
3399
3400         /* Init the replaced_transfers list */
3401         INIT_LIST_HEAD(&rxfer->replaced_transfers);
3402
3403         /*
3404          * Assign the list_entry after which we should reinsert
3405          * the @replaced_transfers - it may be spi_message.messages!
3406          */
3407         rxfer->replaced_after = xfer_first->transfer_list.prev;
3408
3409         /* Remove the requested number of transfers */
3410         for (i = 0; i < remove; i++) {
3411                 /*
3412                  * If the entry after replaced_after it is msg->transfers
3413                  * then we have been requested to remove more transfers
3414                  * than are in the list.
3415                  */
3416                 if (rxfer->replaced_after->next == &msg->transfers) {
3417                         dev_err(&msg->spi->dev,
3418                                 "requested to remove more spi_transfers than are available\n");
3419                         /* Insert replaced transfers back into the message */
3420                         list_splice(&rxfer->replaced_transfers,
3421                                     rxfer->replaced_after);
3422
3423                         /* Free the spi_replace_transfer structure... */
3424                         spi_res_free(rxfer);
3425
3426                         /* ...and return with an error */
3427                         return ERR_PTR(-EINVAL);
3428                 }
3429
3430                 /*
3431                  * Remove the entry after replaced_after from list of
3432                  * transfers and add it to list of replaced_transfers.
3433                  */
3434                 list_move_tail(rxfer->replaced_after->next,
3435                                &rxfer->replaced_transfers);
3436         }
3437
3438         /*
3439          * Create copy of the given xfer with identical settings
3440          * based on the first transfer to get removed.
3441          */
3442         for (i = 0; i < insert; i++) {
3443                 /* We need to run in reverse order */
3444                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
3445
3446                 /* Copy all spi_transfer data */
3447                 memcpy(xfer, xfer_first, sizeof(*xfer));
3448
3449                 /* Add to list */
3450                 list_add(&xfer->transfer_list, rxfer->replaced_after);
3451
3452                 /* Clear cs_change and delay for all but the last */
3453                 if (i) {
3454                         xfer->cs_change = false;
3455                         xfer->delay.value = 0;
3456                 }
3457         }
3458
3459         /* Set up inserted... */
3460         rxfer->inserted = insert;
3461
3462         /* ...and register it with spi_res/spi_message */
3463         spi_res_add(msg, rxfer);
3464
3465         return rxfer;
3466 }
3467
3468 static int __spi_split_transfer_maxsize(struct spi_controller *ctlr,
3469                                         struct spi_message *msg,
3470                                         struct spi_transfer **xferp,
3471                                         size_t maxsize,
3472                                         gfp_t gfp)
3473 {
3474         struct spi_transfer *xfer = *xferp, *xfers;
3475         struct spi_replaced_transfers *srt;
3476         size_t offset;
3477         size_t count, i;
3478
3479         /* Calculate how many we have to replace */
3480         count = DIV_ROUND_UP(xfer->len, maxsize);
3481
3482         /* Create replacement */
3483         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
3484         if (IS_ERR(srt))
3485                 return PTR_ERR(srt);
3486         xfers = srt->inserted_transfers;
3487
3488         /*
3489          * Now handle each of those newly inserted spi_transfers.
3490          * Note that the replacements spi_transfers all are preset
3491          * to the same values as *xferp, so tx_buf, rx_buf and len
3492          * are all identical (as well as most others)
3493          * so we just have to fix up len and the pointers.
3494          *
3495          * This also includes support for the depreciated
3496          * spi_message.is_dma_mapped interface.
3497          */
3498
3499         /*
3500          * The first transfer just needs the length modified, so we
3501          * run it outside the loop.
3502          */
3503         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
3504
3505         /* All the others need rx_buf/tx_buf also set */
3506         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
3507                 /* Update rx_buf, tx_buf and dma */
3508                 if (xfers[i].rx_buf)
3509                         xfers[i].rx_buf += offset;
3510                 if (xfers[i].rx_dma)
3511                         xfers[i].rx_dma += offset;
3512                 if (xfers[i].tx_buf)
3513                         xfers[i].tx_buf += offset;
3514                 if (xfers[i].tx_dma)
3515                         xfers[i].tx_dma += offset;
3516
3517                 /* Update length */
3518                 xfers[i].len = min(maxsize, xfers[i].len - offset);
3519         }
3520
3521         /*
3522          * We set up xferp to the last entry we have inserted,
3523          * so that we skip those already split transfers.
3524          */
3525         *xferp = &xfers[count - 1];
3526
3527         /* Increment statistics counters */
3528         SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics,
3529                                        transfers_split_maxsize);
3530         SPI_STATISTICS_INCREMENT_FIELD(msg->spi->pcpu_statistics,
3531                                        transfers_split_maxsize);
3532
3533         return 0;
3534 }
3535
3536 /**
3537  * spi_split_transfers_maxsize - split spi transfers into multiple transfers
3538  *                               when an individual transfer exceeds a
3539  *                               certain size
3540  * @ctlr:    the @spi_controller for this transfer
3541  * @msg:   the @spi_message to transform
3542  * @maxsize:  the maximum when to apply this
3543  * @gfp: GFP allocation flags
3544  *
3545  * Return: status of transformation
3546  */
3547 int spi_split_transfers_maxsize(struct spi_controller *ctlr,
3548                                 struct spi_message *msg,
3549                                 size_t maxsize,
3550                                 gfp_t gfp)
3551 {
3552         struct spi_transfer *xfer;
3553         int ret;
3554
3555         /*
3556          * Iterate over the transfer_list,
3557          * but note that xfer is advanced to the last transfer inserted
3558          * to avoid checking sizes again unnecessarily (also xfer does
3559          * potentially belong to a different list by the time the
3560          * replacement has happened).
3561          */
3562         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
3563                 if (xfer->len > maxsize) {
3564                         ret = __spi_split_transfer_maxsize(ctlr, msg, &xfer,
3565                                                            maxsize, gfp);
3566                         if (ret)
3567                                 return ret;
3568                 }
3569         }
3570
3571         return 0;
3572 }
3573 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
3574
3575 /*-------------------------------------------------------------------------*/
3576
3577 /* Core methods for SPI controller protocol drivers.  Some of the
3578  * other core methods are currently defined as inline functions.
3579  */
3580
3581 static int __spi_validate_bits_per_word(struct spi_controller *ctlr,
3582                                         u8 bits_per_word)
3583 {
3584         if (ctlr->bits_per_word_mask) {
3585                 /* Only 32 bits fit in the mask */
3586                 if (bits_per_word > 32)
3587                         return -EINVAL;
3588                 if (!(ctlr->bits_per_word_mask & SPI_BPW_MASK(bits_per_word)))
3589                         return -EINVAL;
3590         }
3591
3592         return 0;
3593 }
3594
3595 /**
3596  * spi_setup - setup SPI mode and clock rate
3597  * @spi: the device whose settings are being modified
3598  * Context: can sleep, and no requests are queued to the device
3599  *
3600  * SPI protocol drivers may need to update the transfer mode if the
3601  * device doesn't work with its default.  They may likewise need
3602  * to update clock rates or word sizes from initial values.  This function
3603  * changes those settings, and must be called from a context that can sleep.
3604  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
3605  * effect the next time the device is selected and data is transferred to
3606  * or from it.  When this function returns, the spi device is deselected.
3607  *
3608  * Note that this call will fail if the protocol driver specifies an option
3609  * that the underlying controller or its driver does not support.  For
3610  * example, not all hardware supports wire transfers using nine bit words,
3611  * LSB-first wire encoding, or active-high chipselects.
3612  *
3613  * Return: zero on success, else a negative error code.
3614  */
3615 int spi_setup(struct spi_device *spi)
3616 {
3617         unsigned        bad_bits, ugly_bits;
3618         int             status = 0;
3619
3620         /*
3621          * Check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
3622          * are set at the same time.
3623          */
3624         if ((hweight_long(spi->mode &
3625                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) ||
3626             (hweight_long(spi->mode &
3627                 (SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) {
3628                 dev_err(&spi->dev,
3629                 "setup: can not select any two of dual, quad and no-rx/tx at the same time\n");
3630                 return -EINVAL;
3631         }
3632         /* If it is SPI_3WIRE mode, DUAL and QUAD should be forbidden */
3633         if ((spi->mode & SPI_3WIRE) && (spi->mode &
3634                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3635                  SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL)))
3636                 return -EINVAL;
3637         /*
3638          * Help drivers fail *cleanly* when they need options
3639          * that aren't supported with their current controller.
3640          * SPI_CS_WORD has a fallback software implementation,
3641          * so it is ignored here.
3642          */
3643         bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD |
3644                                  SPI_NO_TX | SPI_NO_RX);
3645         ugly_bits = bad_bits &
3646                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL |
3647                      SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL);
3648         if (ugly_bits) {
3649                 dev_warn(&spi->dev,
3650                          "setup: ignoring unsupported mode bits %x\n",
3651                          ugly_bits);
3652                 spi->mode &= ~ugly_bits;
3653                 bad_bits &= ~ugly_bits;
3654         }
3655         if (bad_bits) {
3656                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
3657                         bad_bits);
3658                 return -EINVAL;
3659         }
3660
3661         if (!spi->bits_per_word) {
3662                 spi->bits_per_word = 8;
3663         } else {
3664                 /*
3665                  * Some controllers may not support the default 8 bits-per-word
3666                  * so only perform the check when this is explicitly provided.
3667                  */
3668                 status = __spi_validate_bits_per_word(spi->controller,
3669                                                       spi->bits_per_word);
3670                 if (status)
3671                         return status;
3672         }
3673
3674         if (spi->controller->max_speed_hz &&
3675             (!spi->max_speed_hz ||
3676              spi->max_speed_hz > spi->controller->max_speed_hz))
3677                 spi->max_speed_hz = spi->controller->max_speed_hz;
3678
3679         mutex_lock(&spi->controller->io_mutex);
3680
3681         if (spi->controller->setup) {
3682                 status = spi->controller->setup(spi);
3683                 if (status) {
3684                         mutex_unlock(&spi->controller->io_mutex);
3685                         dev_err(&spi->controller->dev, "Failed to setup device: %d\n",
3686                                 status);
3687                         return status;
3688                 }
3689         }
3690
3691         if (spi->controller->auto_runtime_pm && spi->controller->set_cs) {
3692                 status = pm_runtime_resume_and_get(spi->controller->dev.parent);
3693                 if (status < 0) {
3694                         mutex_unlock(&spi->controller->io_mutex);
3695                         dev_err(&spi->controller->dev, "Failed to power device: %d\n",
3696                                 status);
3697                         return status;
3698                 }
3699
3700                 /*
3701                  * We do not want to return positive value from pm_runtime_get,
3702                  * there are many instances of devices calling spi_setup() and
3703                  * checking for a non-zero return value instead of a negative
3704                  * return value.
3705                  */
3706                 status = 0;
3707
3708                 spi_set_cs(spi, false, true);
3709                 pm_runtime_mark_last_busy(spi->controller->dev.parent);
3710                 pm_runtime_put_autosuspend(spi->controller->dev.parent);
3711         } else {
3712                 spi_set_cs(spi, false, true);
3713         }
3714
3715         mutex_unlock(&spi->controller->io_mutex);
3716
3717         if (spi->rt && !spi->controller->rt) {
3718                 spi->controller->rt = true;
3719                 spi_set_thread_rt(spi->controller);
3720         }
3721
3722         trace_spi_setup(spi, status);
3723
3724         dev_dbg(&spi->dev, "setup mode %lu, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
3725                         spi->mode & SPI_MODE_X_MASK,
3726                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
3727                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
3728                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
3729                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
3730                         spi->bits_per_word, spi->max_speed_hz,
3731                         status);
3732
3733         return status;
3734 }
3735 EXPORT_SYMBOL_GPL(spi_setup);
3736
3737 static int _spi_xfer_word_delay_update(struct spi_transfer *xfer,
3738                                        struct spi_device *spi)
3739 {
3740         int delay1, delay2;
3741
3742         delay1 = spi_delay_to_ns(&xfer->word_delay, xfer);
3743         if (delay1 < 0)
3744                 return delay1;
3745
3746         delay2 = spi_delay_to_ns(&spi->word_delay, xfer);
3747         if (delay2 < 0)
3748                 return delay2;
3749
3750         if (delay1 < delay2)
3751                 memcpy(&xfer->word_delay, &spi->word_delay,
3752                        sizeof(xfer->word_delay));
3753
3754         return 0;
3755 }
3756
3757 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
3758 {
3759         struct spi_controller *ctlr = spi->controller;
3760         struct spi_transfer *xfer;
3761         int w_size;
3762
3763         if (list_empty(&message->transfers))
3764                 return -EINVAL;
3765
3766         /*
3767          * If an SPI controller does not support toggling the CS line on each
3768          * transfer (indicated by the SPI_CS_WORD flag) or we are using a GPIO
3769          * for the CS line, we can emulate the CS-per-word hardware function by
3770          * splitting transfers into one-word transfers and ensuring that
3771          * cs_change is set for each transfer.
3772          */
3773         if ((spi->mode & SPI_CS_WORD) && (!(ctlr->mode_bits & SPI_CS_WORD) ||
3774                                           spi->cs_gpiod)) {
3775                 size_t maxsize;
3776                 int ret;
3777
3778                 maxsize = (spi->bits_per_word + 7) / 8;
3779
3780                 /* spi_split_transfers_maxsize() requires message->spi */
3781                 message->spi = spi;
3782
3783                 ret = spi_split_transfers_maxsize(ctlr, message, maxsize,
3784                                                   GFP_KERNEL);
3785                 if (ret)
3786                         return ret;
3787
3788                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3789                         /* Don't change cs_change on the last entry in the list */
3790                         if (list_is_last(&xfer->transfer_list, &message->transfers))
3791                                 break;
3792                         xfer->cs_change = 1;
3793                 }
3794         }
3795
3796         /*
3797          * Half-duplex links include original MicroWire, and ones with
3798          * only one data pin like SPI_3WIRE (switches direction) or where
3799          * either MOSI or MISO is missing.  They can also be caused by
3800          * software limitations.
3801          */
3802         if ((ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX) ||
3803             (spi->mode & SPI_3WIRE)) {
3804                 unsigned flags = ctlr->flags;
3805
3806                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3807                         if (xfer->rx_buf && xfer->tx_buf)
3808                                 return -EINVAL;
3809                         if ((flags & SPI_CONTROLLER_NO_TX) && xfer->tx_buf)
3810                                 return -EINVAL;
3811                         if ((flags & SPI_CONTROLLER_NO_RX) && xfer->rx_buf)
3812                                 return -EINVAL;
3813                 }
3814         }
3815
3816         /*
3817          * Set transfer bits_per_word and max speed as spi device default if
3818          * it is not set for this transfer.
3819          * Set transfer tx_nbits and rx_nbits as single transfer default
3820          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
3821          * Ensure transfer word_delay is at least as long as that required by
3822          * device itself.
3823          */
3824         message->frame_length = 0;
3825         list_for_each_entry(xfer, &message->transfers, transfer_list) {
3826                 xfer->effective_speed_hz = 0;
3827                 message->frame_length += xfer->len;
3828                 if (!xfer->bits_per_word)
3829                         xfer->bits_per_word = spi->bits_per_word;
3830
3831                 if (!xfer->speed_hz)
3832                         xfer->speed_hz = spi->max_speed_hz;
3833
3834                 if (ctlr->max_speed_hz && xfer->speed_hz > ctlr->max_speed_hz)
3835                         xfer->speed_hz = ctlr->max_speed_hz;
3836
3837                 if (__spi_validate_bits_per_word(ctlr, xfer->bits_per_word))
3838                         return -EINVAL;
3839
3840                 /*
3841                  * SPI transfer length should be multiple of SPI word size
3842                  * where SPI word size should be power-of-two multiple.
3843                  */
3844                 if (xfer->bits_per_word <= 8)
3845                         w_size = 1;
3846                 else if (xfer->bits_per_word <= 16)
3847                         w_size = 2;
3848                 else
3849                         w_size = 4;
3850
3851                 /* No partial transfers accepted */
3852                 if (xfer->len % w_size)
3853                         return -EINVAL;
3854
3855                 if (xfer->speed_hz && ctlr->min_speed_hz &&
3856                     xfer->speed_hz < ctlr->min_speed_hz)
3857                         return -EINVAL;
3858
3859                 if (xfer->tx_buf && !xfer->tx_nbits)
3860                         xfer->tx_nbits = SPI_NBITS_SINGLE;
3861                 if (xfer->rx_buf && !xfer->rx_nbits)
3862                         xfer->rx_nbits = SPI_NBITS_SINGLE;
3863                 /*
3864                  * Check transfer tx/rx_nbits:
3865                  * 1. check the value matches one of single, dual and quad
3866                  * 2. check tx/rx_nbits match the mode in spi_device
3867                  */
3868                 if (xfer->tx_buf) {
3869                         if (spi->mode & SPI_NO_TX)
3870                                 return -EINVAL;
3871                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
3872                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
3873                                 xfer->tx_nbits != SPI_NBITS_QUAD)
3874                                 return -EINVAL;
3875                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
3876                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
3877                                 return -EINVAL;
3878                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
3879                                 !(spi->mode & SPI_TX_QUAD))
3880                                 return -EINVAL;
3881                 }
3882                 /* Check transfer rx_nbits */
3883                 if (xfer->rx_buf) {
3884                         if (spi->mode & SPI_NO_RX)
3885                                 return -EINVAL;
3886                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
3887                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
3888                                 xfer->rx_nbits != SPI_NBITS_QUAD)
3889                                 return -EINVAL;
3890                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
3891                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
3892                                 return -EINVAL;
3893                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
3894                                 !(spi->mode & SPI_RX_QUAD))
3895                                 return -EINVAL;
3896                 }
3897
3898                 if (_spi_xfer_word_delay_update(xfer, spi))
3899                         return -EINVAL;
3900         }
3901
3902         message->status = -EINPROGRESS;
3903
3904         return 0;
3905 }
3906
3907 static int __spi_async(struct spi_device *spi, struct spi_message *message)
3908 {
3909         struct spi_controller *ctlr = spi->controller;
3910         struct spi_transfer *xfer;
3911
3912         /*
3913          * Some controllers do not support doing regular SPI transfers. Return
3914          * ENOTSUPP when this is the case.
3915          */
3916         if (!ctlr->transfer)
3917                 return -ENOTSUPP;
3918
3919         message->spi = spi;
3920
3921         SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_async);
3922         SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_async);
3923
3924         trace_spi_message_submit(message);
3925
3926         if (!ctlr->ptp_sts_supported) {
3927                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
3928                         xfer->ptp_sts_word_pre = 0;
3929                         ptp_read_system_prets(xfer->ptp_sts);
3930                 }
3931         }
3932
3933         return ctlr->transfer(spi, message);
3934 }
3935
3936 /**
3937  * spi_async - asynchronous SPI transfer
3938  * @spi: device with which data will be exchanged
3939  * @message: describes the data transfers, including completion callback
3940  * Context: any (irqs may be blocked, etc)
3941  *
3942  * This call may be used in_irq and other contexts which can't sleep,
3943  * as well as from task contexts which can sleep.
3944  *
3945  * The completion callback is invoked in a context which can't sleep.
3946  * Before that invocation, the value of message->status is undefined.
3947  * When the callback is issued, message->status holds either zero (to
3948  * indicate complete success) or a negative error code.  After that
3949  * callback returns, the driver which issued the transfer request may
3950  * deallocate the associated memory; it's no longer in use by any SPI
3951  * core or controller driver code.
3952  *
3953  * Note that although all messages to a spi_device are handled in
3954  * FIFO order, messages may go to different devices in other orders.
3955  * Some device might be higher priority, or have various "hard" access
3956  * time requirements, for example.
3957  *
3958  * On detection of any fault during the transfer, processing of
3959  * the entire message is aborted, and the device is deselected.
3960  * Until returning from the associated message completion callback,
3961  * no other spi_message queued to that device will be processed.
3962  * (This rule applies equally to all the synchronous transfer calls,
3963  * which are wrappers around this core asynchronous primitive.)
3964  *
3965  * Return: zero on success, else a negative error code.
3966  */
3967 int spi_async(struct spi_device *spi, struct spi_message *message)
3968 {
3969         struct spi_controller *ctlr = spi->controller;
3970         int ret;
3971         unsigned long flags;
3972
3973         ret = __spi_validate(spi, message);
3974         if (ret != 0)
3975                 return ret;
3976
3977         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
3978
3979         if (ctlr->bus_lock_flag)
3980                 ret = -EBUSY;
3981         else
3982                 ret = __spi_async(spi, message);
3983
3984         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
3985
3986         return ret;
3987 }
3988 EXPORT_SYMBOL_GPL(spi_async);
3989
3990 /**
3991  * spi_async_locked - version of spi_async with exclusive bus usage
3992  * @spi: device with which data will be exchanged
3993  * @message: describes the data transfers, including completion callback
3994  * Context: any (irqs may be blocked, etc)
3995  *
3996  * This call may be used in_irq and other contexts which can't sleep,
3997  * as well as from task contexts which can sleep.
3998  *
3999  * The completion callback is invoked in a context which can't sleep.
4000  * Before that invocation, the value of message->status is undefined.
4001  * When the callback is issued, message->status holds either zero (to
4002  * indicate complete success) or a negative error code.  After that
4003  * callback returns, the driver which issued the transfer request may
4004  * deallocate the associated memory; it's no longer in use by any SPI
4005  * core or controller driver code.
4006  *
4007  * Note that although all messages to a spi_device are handled in
4008  * FIFO order, messages may go to different devices in other orders.
4009  * Some device might be higher priority, or have various "hard" access
4010  * time requirements, for example.
4011  *
4012  * On detection of any fault during the transfer, processing of
4013  * the entire message is aborted, and the device is deselected.
4014  * Until returning from the associated message completion callback,
4015  * no other spi_message queued to that device will be processed.
4016  * (This rule applies equally to all the synchronous transfer calls,
4017  * which are wrappers around this core asynchronous primitive.)
4018  *
4019  * Return: zero on success, else a negative error code.
4020  */
4021 static int spi_async_locked(struct spi_device *spi, struct spi_message *message)
4022 {
4023         struct spi_controller *ctlr = spi->controller;
4024         int ret;
4025         unsigned long flags;
4026
4027         ret = __spi_validate(spi, message);
4028         if (ret != 0)
4029                 return ret;
4030
4031         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4032
4033         ret = __spi_async(spi, message);
4034
4035         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4036
4037         return ret;
4038
4039 }
4040
4041 static void __spi_transfer_message_noqueue(struct spi_controller *ctlr, struct spi_message *msg)
4042 {
4043         bool was_busy;
4044         int ret;
4045
4046         mutex_lock(&ctlr->io_mutex);
4047
4048         was_busy = ctlr->busy;
4049
4050         ctlr->cur_msg = msg;
4051         ret = __spi_pump_transfer_message(ctlr, msg, was_busy);
4052         if (ret)
4053                 goto out;
4054
4055         ctlr->cur_msg = NULL;
4056         ctlr->fallback = false;
4057
4058         if (!was_busy) {
4059                 kfree(ctlr->dummy_rx);
4060                 ctlr->dummy_rx = NULL;
4061                 kfree(ctlr->dummy_tx);
4062                 ctlr->dummy_tx = NULL;
4063                 if (ctlr->unprepare_transfer_hardware &&
4064                     ctlr->unprepare_transfer_hardware(ctlr))
4065                         dev_err(&ctlr->dev,
4066                                 "failed to unprepare transfer hardware\n");
4067                 spi_idle_runtime_pm(ctlr);
4068         }
4069
4070 out:
4071         mutex_unlock(&ctlr->io_mutex);
4072 }
4073
4074 /*-------------------------------------------------------------------------*/
4075
4076 /*
4077  * Utility methods for SPI protocol drivers, layered on
4078  * top of the core.  Some other utility methods are defined as
4079  * inline functions.
4080  */
4081
4082 static void spi_complete(void *arg)
4083 {
4084         complete(arg);
4085 }
4086
4087 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
4088 {
4089         DECLARE_COMPLETION_ONSTACK(done);
4090         int status;
4091         struct spi_controller *ctlr = spi->controller;
4092
4093         status = __spi_validate(spi, message);
4094         if (status != 0)
4095                 return status;
4096
4097         message->spi = spi;
4098
4099         SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync);
4100         SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync);
4101
4102         /*
4103          * Checking queue_empty here only guarantees async/sync message
4104          * ordering when coming from the same context. It does not need to
4105          * guard against reentrancy from a different context. The io_mutex
4106          * will catch those cases.
4107          */
4108         if (READ_ONCE(ctlr->queue_empty) && !ctlr->must_async) {
4109                 message->actual_length = 0;
4110                 message->status = -EINPROGRESS;
4111
4112                 trace_spi_message_submit(message);
4113
4114                 SPI_STATISTICS_INCREMENT_FIELD(ctlr->pcpu_statistics, spi_sync_immediate);
4115                 SPI_STATISTICS_INCREMENT_FIELD(spi->pcpu_statistics, spi_sync_immediate);
4116
4117                 __spi_transfer_message_noqueue(ctlr, message);
4118
4119                 return message->status;
4120         }
4121
4122         /*
4123          * There are messages in the async queue that could have originated
4124          * from the same context, so we need to preserve ordering.
4125          * Therefor we send the message to the async queue and wait until they
4126          * are completed.
4127          */
4128         message->complete = spi_complete;
4129         message->context = &done;
4130         status = spi_async_locked(spi, message);
4131         if (status == 0) {
4132                 wait_for_completion(&done);
4133                 status = message->status;
4134         }
4135         message->context = NULL;
4136
4137         return status;
4138 }
4139
4140 /**
4141  * spi_sync - blocking/synchronous SPI data transfers
4142  * @spi: device with which data will be exchanged
4143  * @message: describes the data transfers
4144  * Context: can sleep
4145  *
4146  * This call may only be used from a context that may sleep.  The sleep
4147  * is non-interruptible, and has no timeout.  Low-overhead controller
4148  * drivers may DMA directly into and out of the message buffers.
4149  *
4150  * Note that the SPI device's chip select is active during the message,
4151  * and then is normally disabled between messages.  Drivers for some
4152  * frequently-used devices may want to minimize costs of selecting a chip,
4153  * by leaving it selected in anticipation that the next message will go
4154  * to the same chip.  (That may increase power usage.)
4155  *
4156  * Also, the caller is guaranteeing that the memory associated with the
4157  * message will not be freed before this call returns.
4158  *
4159  * Return: zero on success, else a negative error code.
4160  */
4161 int spi_sync(struct spi_device *spi, struct spi_message *message)
4162 {
4163         int ret;
4164
4165         mutex_lock(&spi->controller->bus_lock_mutex);
4166         ret = __spi_sync(spi, message);
4167         mutex_unlock(&spi->controller->bus_lock_mutex);
4168
4169         return ret;
4170 }
4171 EXPORT_SYMBOL_GPL(spi_sync);
4172
4173 /**
4174  * spi_sync_locked - version of spi_sync with exclusive bus usage
4175  * @spi: device with which data will be exchanged
4176  * @message: describes the data transfers
4177  * Context: can sleep
4178  *
4179  * This call may only be used from a context that may sleep.  The sleep
4180  * is non-interruptible, and has no timeout.  Low-overhead controller
4181  * drivers may DMA directly into and out of the message buffers.
4182  *
4183  * This call should be used by drivers that require exclusive access to the
4184  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
4185  * be released by a spi_bus_unlock call when the exclusive access is over.
4186  *
4187  * Return: zero on success, else a negative error code.
4188  */
4189 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
4190 {
4191         return __spi_sync(spi, message);
4192 }
4193 EXPORT_SYMBOL_GPL(spi_sync_locked);
4194
4195 /**
4196  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
4197  * @ctlr: SPI bus master that should be locked for exclusive bus access
4198  * Context: can sleep
4199  *
4200  * This call may only be used from a context that may sleep.  The sleep
4201  * is non-interruptible, and has no timeout.
4202  *
4203  * This call should be used by drivers that require exclusive access to the
4204  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
4205  * exclusive access is over. Data transfer must be done by spi_sync_locked
4206  * and spi_async_locked calls when the SPI bus lock is held.
4207  *
4208  * Return: always zero.
4209  */
4210 int spi_bus_lock(struct spi_controller *ctlr)
4211 {
4212         unsigned long flags;
4213
4214         mutex_lock(&ctlr->bus_lock_mutex);
4215
4216         spin_lock_irqsave(&ctlr->bus_lock_spinlock, flags);
4217         ctlr->bus_lock_flag = 1;
4218         spin_unlock_irqrestore(&ctlr->bus_lock_spinlock, flags);
4219
4220         /* Mutex remains locked until spi_bus_unlock() is called */
4221
4222         return 0;
4223 }
4224 EXPORT_SYMBOL_GPL(spi_bus_lock);
4225
4226 /**
4227  * spi_bus_unlock - release the lock for exclusive SPI bus usage
4228  * @ctlr: SPI bus master that was locked for exclusive bus access
4229  * Context: can sleep
4230  *
4231  * This call may only be used from a context that may sleep.  The sleep
4232  * is non-interruptible, and has no timeout.
4233  *
4234  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
4235  * call.
4236  *
4237  * Return: always zero.
4238  */
4239 int spi_bus_unlock(struct spi_controller *ctlr)
4240 {
4241         ctlr->bus_lock_flag = 0;
4242
4243         mutex_unlock(&ctlr->bus_lock_mutex);
4244
4245         return 0;
4246 }
4247 EXPORT_SYMBOL_GPL(spi_bus_unlock);
4248
4249 /* Portable code must never pass more than 32 bytes */
4250 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
4251
4252 static u8       *buf;
4253
4254 /**
4255  * spi_write_then_read - SPI synchronous write followed by read
4256  * @spi: device with which data will be exchanged
4257  * @txbuf: data to be written (need not be dma-safe)
4258  * @n_tx: size of txbuf, in bytes
4259  * @rxbuf: buffer into which data will be read (need not be dma-safe)
4260  * @n_rx: size of rxbuf, in bytes
4261  * Context: can sleep
4262  *
4263  * This performs a half duplex MicroWire style transaction with the
4264  * device, sending txbuf and then reading rxbuf.  The return value
4265  * is zero for success, else a negative errno status code.
4266  * This call may only be used from a context that may sleep.
4267  *
4268  * Parameters to this routine are always copied using a small buffer.
4269  * Performance-sensitive or bulk transfer code should instead use
4270  * spi_{async,sync}() calls with dma-safe buffers.
4271  *
4272  * Return: zero on success, else a negative error code.
4273  */
4274 int spi_write_then_read(struct spi_device *spi,
4275                 const void *txbuf, unsigned n_tx,
4276                 void *rxbuf, unsigned n_rx)
4277 {
4278         static DEFINE_MUTEX(lock);
4279
4280         int                     status;
4281         struct spi_message      message;
4282         struct spi_transfer     x[2];
4283         u8                      *local_buf;
4284
4285         /*
4286          * Use preallocated DMA-safe buffer if we can. We can't avoid
4287          * copying here, (as a pure convenience thing), but we can
4288          * keep heap costs out of the hot path unless someone else is
4289          * using the pre-allocated buffer or the transfer is too large.
4290          */
4291         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
4292                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
4293                                     GFP_KERNEL | GFP_DMA);
4294                 if (!local_buf)
4295                         return -ENOMEM;
4296         } else {
4297                 local_buf = buf;
4298         }
4299
4300         spi_message_init(&message);
4301         memset(x, 0, sizeof(x));
4302         if (n_tx) {
4303                 x[0].len = n_tx;
4304                 spi_message_add_tail(&x[0], &message);
4305         }
4306         if (n_rx) {
4307                 x[1].len = n_rx;
4308                 spi_message_add_tail(&x[1], &message);
4309         }
4310
4311         memcpy(local_buf, txbuf, n_tx);
4312         x[0].tx_buf = local_buf;
4313         x[1].rx_buf = local_buf + n_tx;
4314
4315         /* Do the i/o */
4316         status = spi_sync(spi, &message);
4317         if (status == 0)
4318                 memcpy(rxbuf, x[1].rx_buf, n_rx);
4319
4320         if (x[0].tx_buf == buf)
4321                 mutex_unlock(&lock);
4322         else
4323                 kfree(local_buf);
4324
4325         return status;
4326 }
4327 EXPORT_SYMBOL_GPL(spi_write_then_read);
4328
4329 /*-------------------------------------------------------------------------*/
4330
4331 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
4332 /* Must call put_device() when done with returned spi_device device */
4333 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
4334 {
4335         struct device *dev = bus_find_device_by_of_node(&spi_bus_type, node);
4336
4337         return dev ? to_spi_device(dev) : NULL;
4338 }
4339
4340 /* The spi controllers are not using spi_bus, so we find it with another way */
4341 static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
4342 {
4343         struct device *dev;
4344
4345         dev = class_find_device_by_of_node(&spi_master_class, node);
4346         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4347                 dev = class_find_device_by_of_node(&spi_slave_class, node);
4348         if (!dev)
4349                 return NULL;
4350
4351         /* Reference got in class_find_device */
4352         return container_of(dev, struct spi_controller, dev);
4353 }
4354
4355 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
4356                          void *arg)
4357 {
4358         struct of_reconfig_data *rd = arg;
4359         struct spi_controller *ctlr;
4360         struct spi_device *spi;
4361
4362         switch (of_reconfig_get_state_change(action, arg)) {
4363         case OF_RECONFIG_CHANGE_ADD:
4364                 ctlr = of_find_spi_controller_by_node(rd->dn->parent);
4365                 if (ctlr == NULL)
4366                         return NOTIFY_OK;       /* Not for us */
4367
4368                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
4369                         put_device(&ctlr->dev);
4370                         return NOTIFY_OK;
4371                 }
4372
4373                 spi = of_register_spi_device(ctlr, rd->dn);
4374                 put_device(&ctlr->dev);
4375
4376                 if (IS_ERR(spi)) {
4377                         pr_err("%s: failed to create for '%pOF'\n",
4378                                         __func__, rd->dn);
4379                         of_node_clear_flag(rd->dn, OF_POPULATED);
4380                         return notifier_from_errno(PTR_ERR(spi));
4381                 }
4382                 break;
4383
4384         case OF_RECONFIG_CHANGE_REMOVE:
4385                 /* Already depopulated? */
4386                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
4387                         return NOTIFY_OK;
4388
4389                 /* Find our device by node */
4390                 spi = of_find_spi_device_by_node(rd->dn);
4391                 if (spi == NULL)
4392                         return NOTIFY_OK;       /* No? not meant for us */
4393
4394                 /* Unregister takes one ref away */
4395                 spi_unregister_device(spi);
4396
4397                 /* And put the reference of the find */
4398                 put_device(&spi->dev);
4399                 break;
4400         }
4401
4402         return NOTIFY_OK;
4403 }
4404
4405 static struct notifier_block spi_of_notifier = {
4406         .notifier_call = of_spi_notify,
4407 };
4408 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4409 extern struct notifier_block spi_of_notifier;
4410 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
4411
4412 #if IS_ENABLED(CONFIG_ACPI)
4413 static int spi_acpi_controller_match(struct device *dev, const void *data)
4414 {
4415         return ACPI_COMPANION(dev->parent) == data;
4416 }
4417
4418 static struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
4419 {
4420         struct device *dev;
4421
4422         dev = class_find_device(&spi_master_class, NULL, adev,
4423                                 spi_acpi_controller_match);
4424         if (!dev && IS_ENABLED(CONFIG_SPI_SLAVE))
4425                 dev = class_find_device(&spi_slave_class, NULL, adev,
4426                                         spi_acpi_controller_match);
4427         if (!dev)
4428                 return NULL;
4429
4430         return container_of(dev, struct spi_controller, dev);
4431 }
4432
4433 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
4434 {
4435         struct device *dev;
4436
4437         dev = bus_find_device_by_acpi_dev(&spi_bus_type, adev);
4438         return to_spi_device(dev);
4439 }
4440
4441 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
4442                            void *arg)
4443 {
4444         struct acpi_device *adev = arg;
4445         struct spi_controller *ctlr;
4446         struct spi_device *spi;
4447
4448         switch (value) {
4449         case ACPI_RECONFIG_DEVICE_ADD:
4450                 ctlr = acpi_spi_find_controller_by_adev(acpi_dev_parent(adev));
4451                 if (!ctlr)
4452                         break;
4453
4454                 acpi_register_spi_device(ctlr, adev);
4455                 put_device(&ctlr->dev);
4456                 break;
4457         case ACPI_RECONFIG_DEVICE_REMOVE:
4458                 if (!acpi_device_enumerated(adev))
4459                         break;
4460
4461                 spi = acpi_spi_find_device_by_adev(adev);
4462                 if (!spi)
4463                         break;
4464
4465                 spi_unregister_device(spi);
4466                 put_device(&spi->dev);
4467                 break;
4468         }
4469
4470         return NOTIFY_OK;
4471 }
4472
4473 static struct notifier_block spi_acpi_notifier = {
4474         .notifier_call = acpi_spi_notify,
4475 };
4476 #else
4477 extern struct notifier_block spi_acpi_notifier;
4478 #endif
4479
4480 static int __init spi_init(void)
4481 {
4482         int     status;
4483
4484         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
4485         if (!buf) {
4486                 status = -ENOMEM;
4487                 goto err0;
4488         }
4489
4490         status = bus_register(&spi_bus_type);
4491         if (status < 0)
4492                 goto err1;
4493
4494         status = class_register(&spi_master_class);
4495         if (status < 0)
4496                 goto err2;
4497
4498         if (IS_ENABLED(CONFIG_SPI_SLAVE)) {
4499                 status = class_register(&spi_slave_class);
4500                 if (status < 0)
4501                         goto err3;
4502         }
4503
4504         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
4505                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
4506         if (IS_ENABLED(CONFIG_ACPI))
4507                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
4508
4509         return 0;
4510
4511 err3:
4512         class_unregister(&spi_master_class);
4513 err2:
4514         bus_unregister(&spi_bus_type);
4515 err1:
4516         kfree(buf);
4517         buf = NULL;
4518 err0:
4519         return status;
4520 }
4521
4522 /*
4523  * A board_info is normally registered in arch_initcall(),
4524  * but even essential drivers wait till later.
4525  *
4526  * REVISIT only boardinfo really needs static linking. The rest (device and
4527  * driver registration) _could_ be dynamically linked (modular) ... Costs
4528  * include needing to have boardinfo data structures be much more public.
4529  */
4530 postcore_initcall(spi_init);