drivers/spi/spi.c

   1 /*
   2  * SPI init/core code
   3  *
   4  * Copyright (C) 2005 David Brownell
   5  * Copyright (C) 2008 Secret Lab Technologies Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/init.h>
  21 #include <linux/cache.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/mutex.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/clk/clk-conf.h>
  28 #include <linux/slab.h>
  29 #include <linux/mod_devicetable.h>
  30 #include <linux/spi/spi.h>
  31 #include <linux/of_gpio.h>
  32 #include <linux/pm_runtime.h>
  33 #include <linux/pm_domain.h>
  34 #include <linux/export.h>
  35 #include <linux/sched/rt.h>
  36 #include <linux/delay.h>
  37 #include <linux/kthread.h>
  38 #include <linux/ioport.h>
  39 #include <linux/acpi.h>
  40
  41 #define CREATE_TRACE_POINTS
  42 #include <trace/events/spi.h>
  43
  44 static void spidev_release(struct device *dev)
  45 {
  46         struct spi_device       *spi = to_spi_device(dev);
  47
  48         /* spi masters may cleanup for released devices */
  49         if (spi->master->cleanup)
  50                 spi->master->cleanup(spi);
  51
  52         spi_master_put(spi->master);
  53         kfree(spi);
  54 }
  55
  56 static ssize_t
  57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
  58 {
  59         const struct spi_device *spi = to_spi_device(dev);
  60         int len;
  61
  62         len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
  63         if (len != -ENODEV)
  64                 return len;
  65
  66         return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
  67 }
  68 static DEVICE_ATTR_RO(modalias);
  69
  70 #define SPI_STATISTICS_ATTRS(field, file)                               \
  71 static ssize_t spi_master_##field##_show(struct device *dev,            \
  72                                          struct device_attribute *attr, \
  73                                          char *buf)                     \
  74 {                                                                       \
  75         struct spi_master *master = container_of(dev,                   \
  76                                                  struct spi_master, dev); \
  77         return spi_statistics_##field##_show(&master->statistics, buf); \
  78 }                                                                       \
  79 static struct device_attribute dev_attr_spi_master_##field = {          \
  80         .attr = { .name = file, .mode = S_IRUGO },                      \
  81         .show = spi_master_##field##_show,                              \
  82 };                                                                      \
  83 static ssize_t spi_device_##field##_show(struct device *dev,            \
  84                                          struct device_attribute *attr, \
  85                                         char *buf)                      \
  86 {                                                                       \
  87         struct spi_device *spi = to_spi_device(dev);                    \
  88         return spi_statistics_##field##_show(&spi->statistics, buf);    \
  89 }                                                                       \
  90 static struct device_attribute dev_attr_spi_device_##field = {          \
  91         .attr = { .name = file, .mode = S_IRUGO },                      \
  92         .show = spi_device_##field##_show,                              \
  93 }
  94
  95 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string)      \
  96 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
  97                                             char *buf)                  \
  98 {                                                                       \
  99         unsigned long flags;                                            \
 100         ssize_t len;                                                    \
 101         spin_lock_irqsave(&stat->lock, flags);                          \
 102         len = sprintf(buf, format_string, stat->field);                 \
 103         spin_unlock_irqrestore(&stat->lock, flags);                     \
 104         return len;                                                     \
 105 }                                                                       \
 106 SPI_STATISTICS_ATTRS(name, file)
 107
 108 #define SPI_STATISTICS_SHOW(field, format_string)                       \
 109         SPI_STATISTICS_SHOW_NAME(field, __stringify(field),             \
 110                                  field, format_string)
 111
 112 SPI_STATISTICS_SHOW(messages, "%lu");
 113 SPI_STATISTICS_SHOW(transfers, "%lu");
 114 SPI_STATISTICS_SHOW(errors, "%lu");
 115 SPI_STATISTICS_SHOW(timedout, "%lu");
 116
 117 SPI_STATISTICS_SHOW(spi_sync, "%lu");
 118 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
 119 SPI_STATISTICS_SHOW(spi_async, "%lu");
 120
 121 SPI_STATISTICS_SHOW(bytes, "%llu");
 122 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
 123 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
 124
 125 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number)              \
 126         SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index,           \
 127                                  "transfer_bytes_histo_" number,        \
 128                                  transfer_bytes_histo[index],  "%lu")
 129 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0,  "0-1");
 130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1,  "2-3");
 131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2,  "4-7");
 132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3,  "8-15");
 133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4,  "16-31");
 134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5,  "32-63");
 135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6,  "64-127");
 136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7,  "128-255");
 137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8,  "256-511");
 138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9,  "512-1023");
 139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
 140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
 141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
 142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
 143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
 144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
 145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
 146
 147 SPI_STATISTICS_SHOW(transfers_split_maxsize, "%lu");
 148
 149 static struct attribute *spi_dev_attrs[] = {
 150         &dev_attr_modalias.attr,
 151         NULL,
 152 };
 153
 154 static const struct attribute_group spi_dev_group = {
 155         .attrs  = spi_dev_attrs,
 156 };
 157
 158 static struct attribute *spi_device_statistics_attrs[] = {
 159         &dev_attr_spi_device_messages.attr,
 160         &dev_attr_spi_device_transfers.attr,
 161         &dev_attr_spi_device_errors.attr,
 162         &dev_attr_spi_device_timedout.attr,
 163         &dev_attr_spi_device_spi_sync.attr,
 164         &dev_attr_spi_device_spi_sync_immediate.attr,
 165         &dev_attr_spi_device_spi_async.attr,
 166         &dev_attr_spi_device_bytes.attr,
 167         &dev_attr_spi_device_bytes_rx.attr,
 168         &dev_attr_spi_device_bytes_tx.attr,
 169         &dev_attr_spi_device_transfer_bytes_histo0.attr,
 170         &dev_attr_spi_device_transfer_bytes_histo1.attr,
 171         &dev_attr_spi_device_transfer_bytes_histo2.attr,
 172         &dev_attr_spi_device_transfer_bytes_histo3.attr,
 173         &dev_attr_spi_device_transfer_bytes_histo4.attr,
 174         &dev_attr_spi_device_transfer_bytes_histo5.attr,
 175         &dev_attr_spi_device_transfer_bytes_histo6.attr,
 176         &dev_attr_spi_device_transfer_bytes_histo7.attr,
 177         &dev_attr_spi_device_transfer_bytes_histo8.attr,
 178         &dev_attr_spi_device_transfer_bytes_histo9.attr,
 179         &dev_attr_spi_device_transfer_bytes_histo10.attr,
 180         &dev_attr_spi_device_transfer_bytes_histo11.attr,
 181         &dev_attr_spi_device_transfer_bytes_histo12.attr,
 182         &dev_attr_spi_device_transfer_bytes_histo13.attr,
 183         &dev_attr_spi_device_transfer_bytes_histo14.attr,
 184         &dev_attr_spi_device_transfer_bytes_histo15.attr,
 185         &dev_attr_spi_device_transfer_bytes_histo16.attr,
 186         &dev_attr_spi_device_transfers_split_maxsize.attr,
 187         NULL,
 188 };
 189
 190 static const struct attribute_group spi_device_statistics_group = {
 191         .name  = "statistics",
 192         .attrs  = spi_device_statistics_attrs,
 193 };
 194
 195 static const struct attribute_group *spi_dev_groups[] = {
 196         &spi_dev_group,
 197         &spi_device_statistics_group,
 198         NULL,
 199 };
 200
 201 static struct attribute *spi_master_statistics_attrs[] = {
 202         &dev_attr_spi_master_messages.attr,
 203         &dev_attr_spi_master_transfers.attr,
 204         &dev_attr_spi_master_errors.attr,
 205         &dev_attr_spi_master_timedout.attr,
 206         &dev_attr_spi_master_spi_sync.attr,
 207         &dev_attr_spi_master_spi_sync_immediate.attr,
 208         &dev_attr_spi_master_spi_async.attr,
 209         &dev_attr_spi_master_bytes.attr,
 210         &dev_attr_spi_master_bytes_rx.attr,
 211         &dev_attr_spi_master_bytes_tx.attr,
 212         &dev_attr_spi_master_transfer_bytes_histo0.attr,
 213         &dev_attr_spi_master_transfer_bytes_histo1.attr,
 214         &dev_attr_spi_master_transfer_bytes_histo2.attr,
 215         &dev_attr_spi_master_transfer_bytes_histo3.attr,
 216         &dev_attr_spi_master_transfer_bytes_histo4.attr,
 217         &dev_attr_spi_master_transfer_bytes_histo5.attr,
 218         &dev_attr_spi_master_transfer_bytes_histo6.attr,
 219         &dev_attr_spi_master_transfer_bytes_histo7.attr,
 220         &dev_attr_spi_master_transfer_bytes_histo8.attr,
 221         &dev_attr_spi_master_transfer_bytes_histo9.attr,
 222         &dev_attr_spi_master_transfer_bytes_histo10.attr,
 223         &dev_attr_spi_master_transfer_bytes_histo11.attr,
 224         &dev_attr_spi_master_transfer_bytes_histo12.attr,
 225         &dev_attr_spi_master_transfer_bytes_histo13.attr,
 226         &dev_attr_spi_master_transfer_bytes_histo14.attr,
 227         &dev_attr_spi_master_transfer_bytes_histo15.attr,
 228         &dev_attr_spi_master_transfer_bytes_histo16.attr,
 229         &dev_attr_spi_master_transfers_split_maxsize.attr,
 230         NULL,
 231 };
 232
 233 static const struct attribute_group spi_master_statistics_group = {
 234         .name  = "statistics",
 235         .attrs  = spi_master_statistics_attrs,
 236 };
 237
 238 static const struct attribute_group *spi_master_groups[] = {
 239         &spi_master_statistics_group,
 240         NULL,
 241 };
 242
 243 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
 244                                        struct spi_transfer *xfer,
 245                                        struct spi_master *master)
 246 {
 247         unsigned long flags;
 248         int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
 249
 250         if (l2len < 0)
 251                 l2len = 0;
 252
 253         spin_lock_irqsave(&stats->lock, flags);
 254
 255         stats->transfers++;
 256         stats->transfer_bytes_histo[l2len]++;
 257
 258         stats->bytes += xfer->len;
 259         if ((xfer->tx_buf) &&
 260             (xfer->tx_buf != master->dummy_tx))
 261                 stats->bytes_tx += xfer->len;
 262         if ((xfer->rx_buf) &&
 263             (xfer->rx_buf != master->dummy_rx))
 264                 stats->bytes_rx += xfer->len;
 265
 266         spin_unlock_irqrestore(&stats->lock, flags);
 267 }
 268 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
 269
 270 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
 271  * and the sysfs version makes coldplug work too.
 272  */
 273
 274 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
 275                                                 const struct spi_device *sdev)
 276 {
 277         while (id->name[0]) {
 278                 if (!strcmp(sdev->modalias, id->name))
 279                         return id;
 280                 id++;
 281         }
 282         return NULL;
 283 }
 284
 285 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
 286 {
 287         const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
 288
 289         return spi_match_id(sdrv->id_table, sdev);
 290 }
 291 EXPORT_SYMBOL_GPL(spi_get_device_id);
 292
 293 static int spi_match_device(struct device *dev, struct device_driver *drv)
 294 {
 295         const struct spi_device *spi = to_spi_device(dev);
 296         const struct spi_driver *sdrv = to_spi_driver(drv);
 297
 298         /* Attempt an OF style match */
 299         if (of_driver_match_device(dev, drv))
 300                 return 1;
 301
 302         /* Then try ACPI */
 303         if (acpi_driver_match_device(dev, drv))
 304                 return 1;
 305
 306         if (sdrv->id_table)
 307                 return !!spi_match_id(sdrv->id_table, spi);
 308
 309         return strcmp(spi->modalias, drv->name) == 0;
 310 }
 311
 312 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
 313 {
 314         const struct spi_device         *spi = to_spi_device(dev);
 315         int rc;
 316
 317         rc = acpi_device_uevent_modalias(dev, env);
 318         if (rc != -ENODEV)
 319                 return rc;
 320
 321         add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
 322         return 0;
 323 }
 324
 325 struct bus_type spi_bus_type = {
 326         .name           = "spi",
 327         .dev_groups     = spi_dev_groups,
 328         .match          = spi_match_device,
 329         .uevent         = spi_uevent,
 330 };
 331 EXPORT_SYMBOL_GPL(spi_bus_type);
 332
 333
 334 static int spi_drv_probe(struct device *dev)
 335 {
 336         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 337         struct spi_device               *spi = to_spi_device(dev);
 338         int ret;
 339
 340         ret = of_clk_set_defaults(dev->of_node, false);
 341         if (ret)
 342                 return ret;
 343
 344         if (dev->of_node) {
 345                 spi->irq = of_irq_get(dev->of_node, 0);
 346                 if (spi->irq == -EPROBE_DEFER)
 347                         return -EPROBE_DEFER;
 348                 if (spi->irq < 0)
 349                         spi->irq = 0;
 350         }
 351
 352         ret = dev_pm_domain_attach(dev, true);
 353         if (ret != -EPROBE_DEFER) {
 354                 ret = sdrv->probe(spi);
 355                 if (ret)
 356                         dev_pm_domain_detach(dev, true);
 357         }
 358
 359         return ret;
 360 }
 361
 362 static int spi_drv_remove(struct device *dev)
 363 {
 364         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 365         int ret;
 366
 367         ret = sdrv->remove(to_spi_device(dev));
 368         dev_pm_domain_detach(dev, true);
 369
 370         return ret;
 371 }
 372
 373 static void spi_drv_shutdown(struct device *dev)
 374 {
 375         const struct spi_driver         *sdrv = to_spi_driver(dev->driver);
 376
 377         sdrv->shutdown(to_spi_device(dev));
 378 }
 379
 380 /**
 381  * __spi_register_driver - register a SPI driver
 382  * @owner: owner module of the driver to register
 383  * @sdrv: the driver to register
 384  * Context: can sleep
 385  *
 386  * Return: zero on success, else a negative error code.
 387  */
 388 int __spi_register_driver(struct module *owner, struct spi_driver *sdrv)
 389 {
 390         sdrv->driver.owner = owner;
 391         sdrv->driver.bus = &spi_bus_type;
 392         if (sdrv->probe)
 393                 sdrv->driver.probe = spi_drv_probe;
 394         if (sdrv->remove)
 395                 sdrv->driver.remove = spi_drv_remove;
 396         if (sdrv->shutdown)
 397                 sdrv->driver.shutdown = spi_drv_shutdown;
 398         return driver_register(&sdrv->driver);
 399 }
 400 EXPORT_SYMBOL_GPL(__spi_register_driver);
 401
 402 /*-------------------------------------------------------------------------*/
 403
 404 /* SPI devices should normally not be created by SPI device drivers; that
 405  * would make them board-specific.  Similarly with SPI master drivers.
 406  * Device registration normally goes into like arch/.../mach.../board-YYY.c
 407  * with other readonly (flashable) information about mainboard devices.
 408  */
 409
 410 struct boardinfo {
 411         struct list_head        list;
 412         struct spi_board_info   board_info;
 413 };
 414
 415 static LIST_HEAD(board_list);
 416 static LIST_HEAD(spi_master_list);
 417
 418 /*
 419  * Used to protect add/del opertion for board_info list and
 420  * spi_master list, and their matching process
 421  */
 422 static DEFINE_MUTEX(board_lock);
 423
 424 /**
 425  * spi_alloc_device - Allocate a new SPI device
 426  * @master: Controller to which device is connected
 427  * Context: can sleep
 428  *
 429  * Allows a driver to allocate and initialize a spi_device without
 430  * registering it immediately.  This allows a driver to directly
 431  * fill the spi_device with device parameters before calling
 432  * spi_add_device() on it.
 433  *
 434  * Caller is responsible to call spi_add_device() on the returned
 435  * spi_device structure to add it to the SPI master.  If the caller
 436  * needs to discard the spi_device without adding it, then it should
 437  * call spi_dev_put() on it.
 438  *
 439  * Return: a pointer to the new device, or NULL.
 440  */
 441 struct spi_device *spi_alloc_device(struct spi_master *master)
 442 {
 443         struct spi_device       *spi;
 444
 445         if (!spi_master_get(master))
 446                 return NULL;
 447
 448         spi = kzalloc(sizeof(*spi), GFP_KERNEL);
 449         if (!spi) {
 450                 spi_master_put(master);
 451                 return NULL;
 452         }
 453
 454         spi->master = master;
 455         spi->dev.parent = &master->dev;
 456         spi->dev.bus = &spi_bus_type;
 457         spi->dev.release = spidev_release;
 458         spi->cs_gpio = -ENOENT;
 459
 460         spin_lock_init(&spi->statistics.lock);
 461
 462         device_initialize(&spi->dev);
 463         return spi;
 464 }
 465 EXPORT_SYMBOL_GPL(spi_alloc_device);
 466
 467 static void spi_dev_set_name(struct spi_device *spi)
 468 {
 469         struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
 470
 471         if (adev) {
 472                 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
 473                 return;
 474         }
 475
 476         dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
 477                      spi->chip_select);
 478 }
 479
 480 static int spi_dev_check(struct device *dev, void *data)
 481 {
 482         struct spi_device *spi = to_spi_device(dev);
 483         struct spi_device *new_spi = data;
 484
 485         if (spi->master == new_spi->master &&
 486             spi->chip_select == new_spi->chip_select)
 487                 return -EBUSY;
 488         return 0;
 489 }
 490
 491 /**
 492  * spi_add_device - Add spi_device allocated with spi_alloc_device
 493  * @spi: spi_device to register
 494  *
 495  * Companion function to spi_alloc_device.  Devices allocated with
 496  * spi_alloc_device can be added onto the spi bus with this function.
 497  *
 498  * Return: 0 on success; negative errno on failure
 499  */
 500 int spi_add_device(struct spi_device *spi)
 501 {
 502         static DEFINE_MUTEX(spi_add_lock);
 503         struct spi_master *master = spi->master;
 504         struct device *dev = master->dev.parent;
 505         int status;
 506
 507         /* Chipselects are numbered 0..max; validate. */
 508         if (spi->chip_select >= master->num_chipselect) {
 509                 dev_err(dev, "cs%d >= max %d\n",
 510                         spi->chip_select,
 511                         master->num_chipselect);
 512                 return -EINVAL;
 513         }
 514
 515         /* Set the bus ID string */
 516         spi_dev_set_name(spi);
 517
 518         /* We need to make sure there's no other device with this
 519          * chipselect **BEFORE** we call setup(), else we'll trash
 520          * its configuration.  Lock against concurrent add() calls.
 521          */
 522         mutex_lock(&spi_add_lock);
 523
 524         status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
 525         if (status) {
 526                 dev_err(dev, "chipselect %d already in use\n",
 527                                 spi->chip_select);
 528                 goto done;
 529         }
 530
 531         if (master->cs_gpios)
 532                 spi->cs_gpio = master->cs_gpios[spi->chip_select];
 533
 534         /* Drivers may modify this initial i/o setup, but will
 535          * normally rely on the device being setup.  Devices
 536          * using SPI_CS_HIGH can't coexist well otherwise...
 537          */
 538         status = spi_setup(spi);
 539         if (status < 0) {
 540                 dev_err(dev, "can't setup %s, status %d\n",
 541                                 dev_name(&spi->dev), status);
 542                 goto done;
 543         }
 544
 545         /* Device may be bound to an active driver when this returns */
 546         status = device_add(&spi->dev);
 547         if (status < 0)
 548                 dev_err(dev, "can't add %s, status %d\n",
 549                                 dev_name(&spi->dev), status);
 550         else
 551                 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
 552
 553 done:
 554         mutex_unlock(&spi_add_lock);
 555         return status;
 556 }
 557 EXPORT_SYMBOL_GPL(spi_add_device);
 558
 559 /**
 560  * spi_new_device - instantiate one new SPI device
 561  * @master: Controller to which device is connected
 562  * @chip: Describes the SPI device
 563  * Context: can sleep
 564  *
 565  * On typical mainboards, this is purely internal; and it's not needed
 566  * after board init creates the hard-wired devices.  Some development
 567  * platforms may not be able to use spi_register_board_info though, and
 568  * this is exported so that for example a USB or parport based adapter
 569  * driver could add devices (which it would learn about out-of-band).
 570  *
 571  * Return: the new device, or NULL.
 572  */
 573 struct spi_device *spi_new_device(struct spi_master *master,
 574                                   struct spi_board_info *chip)
 575 {
 576         struct spi_device       *proxy;
 577         int                     status;
 578
 579         /* NOTE:  caller did any chip->bus_num checks necessary.
 580          *
 581          * Also, unless we change the return value convention to use
 582          * error-or-pointer (not NULL-or-pointer), troubleshootability
 583          * suggests syslogged diagnostics are best here (ugh).
 584          */
 585
 586         proxy = spi_alloc_device(master);
 587         if (!proxy)
 588                 return NULL;
 589
 590         WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
 591
 592         proxy->chip_select = chip->chip_select;
 593         proxy->max_speed_hz = chip->max_speed_hz;
 594         proxy->mode = chip->mode;
 595         proxy->irq = chip->irq;
 596         strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
 597         proxy->dev.platform_data = (void *) chip->platform_data;
 598         proxy->controller_data = chip->controller_data;
 599         proxy->controller_state = NULL;
 600
 601         status = spi_add_device(proxy);
 602         if (status < 0) {
 603                 spi_dev_put(proxy);
 604                 return NULL;
 605         }
 606
 607         return proxy;
 608 }
 609 EXPORT_SYMBOL_GPL(spi_new_device);
 610
 611 /**
 612  * spi_unregister_device - unregister a single SPI device
 613  * @spi: spi_device to unregister
 614  *
 615  * Start making the passed SPI device vanish. Normally this would be handled
 616  * by spi_unregister_master().
 617  */
 618 void spi_unregister_device(struct spi_device *spi)
 619 {
 620         if (!spi)
 621                 return;
 622
 623         if (spi->dev.of_node)
 624                 of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
 625         if (ACPI_COMPANION(&spi->dev))
 626                 acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 627         device_unregister(&spi->dev);
 628 }
 629 EXPORT_SYMBOL_GPL(spi_unregister_device);
 630
 631 static void spi_match_master_to_boardinfo(struct spi_master *master,
 632                                 struct spi_board_info *bi)
 633 {
 634         struct spi_device *dev;
 635
 636         if (master->bus_num != bi->bus_num)
 637                 return;
 638
 639         dev = spi_new_device(master, bi);
 640         if (!dev)
 641                 dev_err(master->dev.parent, "can't create new device for %s\n",
 642                         bi->modalias);
 643 }
 644
 645 /**
 646  * spi_register_board_info - register SPI devices for a given board
 647  * @info: array of chip descriptors
 648  * @n: how many descriptors are provided
 649  * Context: can sleep
 650  *
 651  * Board-specific early init code calls this (probably during arch_initcall)
 652  * with segments of the SPI device table.  Any device nodes are created later,
 653  * after the relevant parent SPI controller (bus_num) is defined.  We keep
 654  * this table of devices forever, so that reloading a controller driver will
 655  * not make Linux forget about these hard-wired devices.
 656  *
 657  * Other code can also call this, e.g. a particular add-on board might provide
 658  * SPI devices through its expansion connector, so code initializing that board
 659  * would naturally declare its SPI devices.
 660  *
 661  * The board info passed can safely be __initdata ... but be careful of
 662  * any embedded pointers (platform_data, etc), they're copied as-is.
 663  *
 664  * Return: zero on success, else a negative error code.
 665  */
 666 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
 667 {
 668         struct boardinfo *bi;
 669         int i;
 670
 671         if (!n)
 672                 return -EINVAL;
 673
 674         bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
 675         if (!bi)
 676                 return -ENOMEM;
 677
 678         for (i = 0; i < n; i++, bi++, info++) {
 679                 struct spi_master *master;
 680
 681                 memcpy(&bi->board_info, info, sizeof(*info));
 682                 mutex_lock(&board_lock);
 683                 list_add_tail(&bi->list, &board_list);
 684                 list_for_each_entry(master, &spi_master_list, list)
 685                         spi_match_master_to_boardinfo(master, &bi->board_info);
 686                 mutex_unlock(&board_lock);
 687         }
 688
 689         return 0;
 690 }
 691
 692 /*-------------------------------------------------------------------------*/
 693
 694 static void spi_set_cs(struct spi_device *spi, bool enable)
 695 {
 696         if (spi->mode & SPI_CS_HIGH)
 697                 enable = !enable;
 698
 699         if (gpio_is_valid(spi->cs_gpio))
 700                 gpio_set_value(spi->cs_gpio, !enable);
 701         else if (spi->master->set_cs)
 702                 spi->master->set_cs(spi, !enable);
 703 }
 704
 705 #ifdef CONFIG_HAS_DMA
 706 static int spi_map_buf(struct spi_master *master, struct device *dev,
 707                        struct sg_table *sgt, void *buf, size_t len,
 708                        enum dma_data_direction dir)
 709 {
 710         const bool vmalloced_buf = is_vmalloc_addr(buf);
 711         unsigned int max_seg_size = dma_get_max_seg_size(dev);
 712         int desc_len;
 713         int sgs;
 714         struct page *vm_page;
 715         void *sg_buf;
 716         size_t min;
 717         int i, ret;
 718
 719         if (vmalloced_buf) {
 720                 desc_len = min_t(int, max_seg_size, PAGE_SIZE);
 721                 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
 722         } else if (virt_addr_valid(buf)) {
 723                 desc_len = min_t(int, max_seg_size, master->max_dma_len);
 724                 sgs = DIV_ROUND_UP(len, desc_len);
 725         } else {
 726                 return -EINVAL;
 727         }
 728
 729         ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
 730         if (ret != 0)
 731                 return ret;
 732
 733         for (i = 0; i < sgs; i++) {
 734
 735                 if (vmalloced_buf) {
 736                         min = min_t(size_t,
 737                                     len, desc_len - offset_in_page(buf));
 738                         vm_page = vmalloc_to_page(buf);
 739                         if (!vm_page) {
 740                                 sg_free_table(sgt);
 741                                 return -ENOMEM;
 742                         }
 743                         sg_set_page(&sgt->sgl[i], vm_page,
 744                                     min, offset_in_page(buf));
 745                 } else {
 746                         min = min_t(size_t, len, desc_len);
 747                         sg_buf = buf;
 748                         sg_set_buf(&sgt->sgl[i], sg_buf, min);
 749                 }
 750
 751                 buf += min;
 752                 len -= min;
 753         }
 754
 755         ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
 756         if (!ret)
 757                 ret = -ENOMEM;
 758         if (ret < 0) {
 759                 sg_free_table(sgt);
 760                 return ret;
 761         }
 762
 763         sgt->nents = ret;
 764
 765         return 0;
 766 }
 767
 768 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
 769                           struct sg_table *sgt, enum dma_data_direction dir)
 770 {
 771         if (sgt->orig_nents) {
 772                 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
 773                 sg_free_table(sgt);
 774         }
 775 }
 776
 777 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
 778 {
 779         struct device *tx_dev, *rx_dev;
 780         struct spi_transfer *xfer;
 781         int ret;
 782
 783         if (!master->can_dma)
 784                 return 0;
 785
 786         if (master->dma_tx)
 787                 tx_dev = master->dma_tx->device->dev;
 788         else
 789                 tx_dev = &master->dev;
 790
 791         if (master->dma_rx)
 792                 rx_dev = master->dma_rx->device->dev;
 793         else
 794                 rx_dev = &master->dev;
 795
 796         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 797                 if (!master->can_dma(master, msg->spi, xfer))
 798                         continue;
 799
 800                 if (xfer->tx_buf != NULL) {
 801                         ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
 802                                           (void *)xfer->tx_buf, xfer->len,
 803                                           DMA_TO_DEVICE);
 804                         if (ret != 0)
 805                                 return ret;
 806                 }
 807
 808                 if (xfer->rx_buf != NULL) {
 809                         ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
 810                                           xfer->rx_buf, xfer->len,
 811                                           DMA_FROM_DEVICE);
 812                         if (ret != 0) {
 813                                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
 814                                               DMA_TO_DEVICE);
 815                                 return ret;
 816                         }
 817                 }
 818         }
 819
 820         master->cur_msg_mapped = true;
 821
 822         return 0;
 823 }
 824
 825 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
 826 {
 827         struct spi_transfer *xfer;
 828         struct device *tx_dev, *rx_dev;
 829
 830         if (!master->cur_msg_mapped || !master->can_dma)
 831                 return 0;
 832
 833         if (master->dma_tx)
 834                 tx_dev = master->dma_tx->device->dev;
 835         else
 836                 tx_dev = &master->dev;
 837
 838         if (master->dma_rx)
 839                 rx_dev = master->dma_rx->device->dev;
 840         else
 841                 rx_dev = &master->dev;
 842
 843         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 844                 if (!master->can_dma(master, msg->spi, xfer))
 845                         continue;
 846
 847                 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
 848                 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
 849         }
 850
 851         return 0;
 852 }
 853 #else /* !CONFIG_HAS_DMA */
 854 static inline int spi_map_buf(struct spi_master *master,
 855                               struct device *dev, struct sg_table *sgt,
 856                               void *buf, size_t len,
 857                               enum dma_data_direction dir)
 858 {
 859         return -EINVAL;
 860 }
 861
 862 static inline void spi_unmap_buf(struct spi_master *master,
 863                                  struct device *dev, struct sg_table *sgt,
 864                                  enum dma_data_direction dir)
 865 {
 866 }
 867
 868 static inline int __spi_map_msg(struct spi_master *master,
 869                                 struct spi_message *msg)
 870 {
 871         return 0;
 872 }
 873
 874 static inline int __spi_unmap_msg(struct spi_master *master,
 875                                   struct spi_message *msg)
 876 {
 877         return 0;
 878 }
 879 #endif /* !CONFIG_HAS_DMA */
 880
 881 static inline int spi_unmap_msg(struct spi_master *master,
 882                                 struct spi_message *msg)
 883 {
 884         struct spi_transfer *xfer;
 885
 886         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 887                 /*
 888                  * Restore the original value of tx_buf or rx_buf if they are
 889                  * NULL.
 890                  */
 891                 if (xfer->tx_buf == master->dummy_tx)
 892                         xfer->tx_buf = NULL;
 893                 if (xfer->rx_buf == master->dummy_rx)
 894                         xfer->rx_buf = NULL;
 895         }
 896
 897         return __spi_unmap_msg(master, msg);
 898 }
 899
 900 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
 901 {
 902         struct spi_transfer *xfer;
 903         void *tmp;
 904         unsigned int max_tx, max_rx;
 905
 906         if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
 907                 max_tx = 0;
 908                 max_rx = 0;
 909
 910                 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 911                         if ((master->flags & SPI_MASTER_MUST_TX) &&
 912                             !xfer->tx_buf)
 913                                 max_tx = max(xfer->len, max_tx);
 914                         if ((master->flags & SPI_MASTER_MUST_RX) &&
 915                             !xfer->rx_buf)
 916                                 max_rx = max(xfer->len, max_rx);
 917                 }
 918
 919                 if (max_tx) {
 920                         tmp = krealloc(master->dummy_tx, max_tx,
 921                                        GFP_KERNEL | GFP_DMA);
 922                         if (!tmp)
 923                                 return -ENOMEM;
 924                         master->dummy_tx = tmp;
 925                         memset(tmp, 0, max_tx);
 926                 }
 927
 928                 if (max_rx) {
 929                         tmp = krealloc(master->dummy_rx, max_rx,
 930                                        GFP_KERNEL | GFP_DMA);
 931                         if (!tmp)
 932                                 return -ENOMEM;
 933                         master->dummy_rx = tmp;
 934                 }
 935
 936                 if (max_tx || max_rx) {
 937                         list_for_each_entry(xfer, &msg->transfers,
 938                                             transfer_list) {
 939                                 if (!xfer->tx_buf)
 940                                         xfer->tx_buf = master->dummy_tx;
 941                                 if (!xfer->rx_buf)
 942                                         xfer->rx_buf = master->dummy_rx;
 943                         }
 944                 }
 945         }
 946
 947         return __spi_map_msg(master, msg);
 948 }
 949
 950 /*
 951  * spi_transfer_one_message - Default implementation of transfer_one_message()
 952  *
 953  * This is a standard implementation of transfer_one_message() for
 954  * drivers which implement a transfer_one() operation.  It provides
 955  * standard handling of delays and chip select management.
 956  */
 957 static int spi_transfer_one_message(struct spi_master *master,
 958                                     struct spi_message *msg)
 959 {
 960         struct spi_transfer *xfer;
 961         bool keep_cs = false;
 962         int ret = 0;
 963         unsigned long ms = 1;
 964         struct spi_statistics *statm = &master->statistics;
 965         struct spi_statistics *stats = &msg->spi->statistics;
 966
 967         spi_set_cs(msg->spi, true);
 968
 969         SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
 970         SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
 971
 972         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 973                 trace_spi_transfer_start(msg, xfer);
 974
 975                 spi_statistics_add_transfer_stats(statm, xfer, master);
 976                 spi_statistics_add_transfer_stats(stats, xfer, master);
 977
 978                 if (xfer->tx_buf || xfer->rx_buf) {
 979                         reinit_completion(&master->xfer_completion);
 980
 981                         ret = master->transfer_one(master, msg->spi, xfer);
 982                         if (ret < 0) {
 983                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
 984                                                                errors);
 985                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
 986                                                                errors);
 987                                 dev_err(&msg->spi->dev,
 988                                         "SPI transfer failed: %d\n", ret);
 989                                 goto out;
 990                         }
 991
 992                         if (ret > 0) {
 993                                 ret = 0;
 994                                 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
 995                                 ms += ms + 100; /* some tolerance */
 996
 997                                 ms = wait_for_completion_timeout(&master->xfer_completion,
 998                                                                  msecs_to_jiffies(ms));
 999                         }
1000
1001                         if (ms == 0) {
1002                                 SPI_STATISTICS_INCREMENT_FIELD(statm,
1003                                                                timedout);
1004                                 SPI_STATISTICS_INCREMENT_FIELD(stats,
1005                                                                timedout);
1006                                 dev_err(&msg->spi->dev,
1007                                         "SPI transfer timed out\n");
1008                                 msg->status = -ETIMEDOUT;
1009                         }
1010                 } else {
1011                         if (xfer->len)
1012                                 dev_err(&msg->spi->dev,
1013                                         "Bufferless transfer has length %u\n",
1014                                         xfer->len);
1015                 }
1016
1017                 trace_spi_transfer_stop(msg, xfer);
1018
1019                 if (msg->status != -EINPROGRESS)
1020                         goto out;
1021
1022                 if (xfer->delay_usecs)
1023                         udelay(xfer->delay_usecs);
1024
1025                 if (xfer->cs_change) {
1026                         if (list_is_last(&xfer->transfer_list,
1027                                          &msg->transfers)) {
1028                                 keep_cs = true;
1029                         } else {
1030                                 spi_set_cs(msg->spi, false);
1031                                 udelay(10);
1032                                 spi_set_cs(msg->spi, true);
1033                         }
1034                 }
1035
1036                 msg->actual_length += xfer->len;
1037         }
1038
1039 out:
1040         if (ret != 0 || !keep_cs)
1041                 spi_set_cs(msg->spi, false);
1042
1043         if (msg->status == -EINPROGRESS)
1044                 msg->status = ret;
1045
1046         if (msg->status && master->handle_err)
1047                 master->handle_err(master, msg);
1048
1049         spi_res_release(master, msg);
1050
1051         spi_finalize_current_message(master);
1052
1053         return ret;
1054 }
1055
1056 /**
1057  * spi_finalize_current_transfer - report completion of a transfer
1058  * @master: the master reporting completion
1059  *
1060  * Called by SPI drivers using the core transfer_one_message()
1061  * implementation to notify it that the current interrupt driven
1062  * transfer has finished and the next one may be scheduled.
1063  */
1064 void spi_finalize_current_transfer(struct spi_master *master)
1065 {
1066         complete(&master->xfer_completion);
1067 }
1068 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1069
1070 /**
1071  * __spi_pump_messages - function which processes spi message queue
1072  * @master: master to process queue for
1073  * @in_kthread: true if we are in the context of the message pump thread
1074  *
1075  * This function checks if there is any spi message in the queue that
1076  * needs processing and if so call out to the driver to initialize hardware
1077  * and transfer each message.
1078  *
1079  * Note that it is called both from the kthread itself and also from
1080  * inside spi_sync(); the queue extraction handling at the top of the
1081  * function should deal with this safely.
1082  */
1083 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1084 {
1085         unsigned long flags;
1086         bool was_busy = false;
1087         int ret;
1088
1089         /* Lock queue */
1090         spin_lock_irqsave(&master->queue_lock, flags);
1091
1092         /* Make sure we are not already running a message */
1093         if (master->cur_msg) {
1094                 spin_unlock_irqrestore(&master->queue_lock, flags);
1095                 return;
1096         }
1097
1098         /* If another context is idling the device then defer */
1099         if (master->idling) {
1100                 queue_kthread_work(&master->kworker, &master->pump_messages);
1101                 spin_unlock_irqrestore(&master->queue_lock, flags);
1102                 return;
1103         }
1104
1105         /* Check if the queue is idle */
1106         if (list_empty(&master->queue) || !master->running) {
1107                 if (!master->busy) {
1108                         spin_unlock_irqrestore(&master->queue_lock, flags);
1109                         return;
1110                 }
1111
1112                 /* Only do teardown in the thread */
1113                 if (!in_kthread) {
1114                         queue_kthread_work(&master->kworker,
1115                                            &master->pump_messages);
1116                         spin_unlock_irqrestore(&master->queue_lock, flags);
1117                         return;
1118                 }
1119
1120                 master->busy = false;
1121                 master->idling = true;
1122                 spin_unlock_irqrestore(&master->queue_lock, flags);
1123
1124                 kfree(master->dummy_rx);
1125                 master->dummy_rx = NULL;
1126                 kfree(master->dummy_tx);
1127                 master->dummy_tx = NULL;
1128                 if (master->unprepare_transfer_hardware &&
1129                     master->unprepare_transfer_hardware(master))
1130                         dev_err(&master->dev,
1131                                 "failed to unprepare transfer hardware\n");
1132                 if (master->auto_runtime_pm) {
1133                         pm_runtime_mark_last_busy(master->dev.parent);
1134                         pm_runtime_put_autosuspend(master->dev.parent);
1135                 }
1136                 trace_spi_master_idle(master);
1137
1138                 spin_lock_irqsave(&master->queue_lock, flags);
1139                 master->idling = false;
1140                 spin_unlock_irqrestore(&master->queue_lock, flags);
1141                 return;
1142         }
1143
1144         /* Extract head of queue */
1145         master->cur_msg =
1146                 list_first_entry(&master->queue, struct spi_message, queue);
1147
1148         list_del_init(&master->cur_msg->queue);
1149         if (master->busy)
1150                 was_busy = true;
1151         else
1152                 master->busy = true;
1153         spin_unlock_irqrestore(&master->queue_lock, flags);
1154
1155         mutex_lock(&master->io_mutex);
1156
1157         if (!was_busy && master->auto_runtime_pm) {
1158                 ret = pm_runtime_get_sync(master->dev.parent);
1159                 if (ret < 0) {
1160                         dev_err(&master->dev, "Failed to power device: %d\n",
1161                                 ret);
1162                         mutex_unlock(&master->io_mutex);
1163                         return;
1164                 }
1165         }
1166
1167         if (!was_busy)
1168                 trace_spi_master_busy(master);
1169
1170         if (!was_busy && master->prepare_transfer_hardware) {
1171                 ret = master->prepare_transfer_hardware(master);
1172                 if (ret) {
1173                         dev_err(&master->dev,
1174                                 "failed to prepare transfer hardware\n");
1175
1176                         if (master->auto_runtime_pm)
1177                                 pm_runtime_put(master->dev.parent);
1178                         mutex_unlock(&master->io_mutex);
1179                         return;
1180                 }
1181         }
1182
1183         trace_spi_message_start(master->cur_msg);
1184
1185         if (master->prepare_message) {
1186                 ret = master->prepare_message(master, master->cur_msg);
1187                 if (ret) {
1188                         dev_err(&master->dev,
1189                                 "failed to prepare message: %d\n", ret);
1190                         master->cur_msg->status = ret;
1191                         spi_finalize_current_message(master);
1192                         goto out;
1193                 }
1194                 master->cur_msg_prepared = true;
1195         }
1196
1197         ret = spi_map_msg(master, master->cur_msg);
1198         if (ret) {
1199                 master->cur_msg->status = ret;
1200                 spi_finalize_current_message(master);
1201                 goto out;
1202         }
1203
1204         ret = master->transfer_one_message(master, master->cur_msg);
1205         if (ret) {
1206                 dev_err(&master->dev,
1207                         "failed to transfer one message from queue\n");
1208                 goto out;
1209         }
1210
1211 out:
1212         mutex_unlock(&master->io_mutex);
1213
1214         /* Prod the scheduler in case transfer_one() was busy waiting */
1215         if (!ret)
1216                 cond_resched();
1217 }
1218
1219 /**
1220  * spi_pump_messages - kthread work function which processes spi message queue
1221  * @work: pointer to kthread work struct contained in the master struct
1222  */
1223 static void spi_pump_messages(struct kthread_work *work)
1224 {
1225         struct spi_master *master =
1226                 container_of(work, struct spi_master, pump_messages);
1227
1228         __spi_pump_messages(master, true);
1229 }
1230
1231 static int spi_init_queue(struct spi_master *master)
1232 {
1233         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1234
1235         master->running = false;
1236         master->busy = false;
1237
1238         init_kthread_worker(&master->kworker);
1239         master->kworker_task = kthread_run(kthread_worker_fn,
1240                                            &master->kworker, "%s",
1241                                            dev_name(&master->dev));
1242         if (IS_ERR(master->kworker_task)) {
1243                 dev_err(&master->dev, "failed to create message pump task\n");
1244                 return PTR_ERR(master->kworker_task);
1245         }
1246         init_kthread_work(&master->pump_messages, spi_pump_messages);
1247
1248         /*
1249          * Master config will indicate if this controller should run the
1250          * message pump with high (realtime) priority to reduce the transfer
1251          * latency on the bus by minimising the delay between a transfer
1252          * request and the scheduling of the message pump thread. Without this
1253          * setting the message pump thread will remain at default priority.
1254          */
1255         if (master->rt) {
1256                 dev_info(&master->dev,
1257                         "will run message pump with realtime priority\n");
1258                 sched_setscheduler(master->kworker_task, SCHED_FIFO, &param);
1259         }
1260
1261         return 0;
1262 }
1263
1264 /**
1265  * spi_get_next_queued_message() - called by driver to check for queued
1266  * messages
1267  * @master: the master to check for queued messages
1268  *
1269  * If there are more messages in the queue, the next message is returned from
1270  * this call.
1271  *
1272  * Return: the next message in the queue, else NULL if the queue is empty.
1273  */
1274 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1275 {
1276         struct spi_message *next;
1277         unsigned long flags;
1278
1279         /* get a pointer to the next message, if any */
1280         spin_lock_irqsave(&master->queue_lock, flags);
1281         next = list_first_entry_or_null(&master->queue, struct spi_message,
1282                                         queue);
1283         spin_unlock_irqrestore(&master->queue_lock, flags);
1284
1285         return next;
1286 }
1287 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1288
1289 /**
1290  * spi_finalize_current_message() - the current message is complete
1291  * @master: the master to return the message to
1292  *
1293  * Called by the driver to notify the core that the message in the front of the
1294  * queue is complete and can be removed from the queue.
1295  */
1296 void spi_finalize_current_message(struct spi_master *master)
1297 {
1298         struct spi_message *mesg;
1299         unsigned long flags;
1300         int ret;
1301
1302         spin_lock_irqsave(&master->queue_lock, flags);
1303         mesg = master->cur_msg;
1304         spin_unlock_irqrestore(&master->queue_lock, flags);
1305
1306         spi_unmap_msg(master, mesg);
1307
1308         if (master->cur_msg_prepared && master->unprepare_message) {
1309                 ret = master->unprepare_message(master, mesg);
1310                 if (ret) {
1311                         dev_err(&master->dev,
1312                                 "failed to unprepare message: %d\n", ret);
1313                 }
1314         }
1315
1316         spin_lock_irqsave(&master->queue_lock, flags);
1317         master->cur_msg = NULL;
1318         master->cur_msg_prepared = false;
1319         queue_kthread_work(&master->kworker, &master->pump_messages);
1320         spin_unlock_irqrestore(&master->queue_lock, flags);
1321
1322         trace_spi_message_done(mesg);
1323
1324         mesg->state = NULL;
1325         if (mesg->complete)
1326                 mesg->complete(mesg->context);
1327 }
1328 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1329
1330 static int spi_start_queue(struct spi_master *master)
1331 {
1332         unsigned long flags;
1333
1334         spin_lock_irqsave(&master->queue_lock, flags);
1335
1336         if (master->running || master->busy) {
1337                 spin_unlock_irqrestore(&master->queue_lock, flags);
1338                 return -EBUSY;
1339         }
1340
1341         master->running = true;
1342         master->cur_msg = NULL;
1343         spin_unlock_irqrestore(&master->queue_lock, flags);
1344
1345         queue_kthread_work(&master->kworker, &master->pump_messages);
1346
1347         return 0;
1348 }
1349
1350 static int spi_stop_queue(struct spi_master *master)
1351 {
1352         unsigned long flags;
1353         unsigned limit = 500;
1354         int ret = 0;
1355
1356         spin_lock_irqsave(&master->queue_lock, flags);
1357
1358         /*
1359          * This is a bit lame, but is optimized for the common execution path.
1360          * A wait_queue on the master->busy could be used, but then the common
1361          * execution path (pump_messages) would be required to call wake_up or
1362          * friends on every SPI message. Do this instead.
1363          */
1364         while ((!list_empty(&master->queue) || master->busy) && limit--) {
1365                 spin_unlock_irqrestore(&master->queue_lock, flags);
1366                 usleep_range(10000, 11000);
1367                 spin_lock_irqsave(&master->queue_lock, flags);
1368         }
1369
1370         if (!list_empty(&master->queue) || master->busy)
1371                 ret = -EBUSY;
1372         else
1373                 master->running = false;
1374
1375         spin_unlock_irqrestore(&master->queue_lock, flags);
1376
1377         if (ret) {
1378                 dev_warn(&master->dev,
1379                          "could not stop message queue\n");
1380                 return ret;
1381         }
1382         return ret;
1383 }
1384
1385 static int spi_destroy_queue(struct spi_master *master)
1386 {
1387         int ret;
1388
1389         ret = spi_stop_queue(master);
1390
1391         /*
1392          * flush_kthread_worker will block until all work is done.
1393          * If the reason that stop_queue timed out is that the work will never
1394          * finish, then it does no good to call flush/stop thread, so
1395          * return anyway.
1396          */
1397         if (ret) {
1398                 dev_err(&master->dev, "problem destroying queue\n");
1399                 return ret;
1400         }
1401
1402         flush_kthread_worker(&master->kworker);
1403         kthread_stop(master->kworker_task);
1404
1405         return 0;
1406 }
1407
1408 static int __spi_queued_transfer(struct spi_device *spi,
1409                                  struct spi_message *msg,
1410                                  bool need_pump)
1411 {
1412         struct spi_master *master = spi->master;
1413         unsigned long flags;
1414
1415         spin_lock_irqsave(&master->queue_lock, flags);
1416
1417         if (!master->running) {
1418                 spin_unlock_irqrestore(&master->queue_lock, flags);
1419                 return -ESHUTDOWN;
1420         }
1421         msg->actual_length = 0;
1422         msg->status = -EINPROGRESS;
1423
1424         list_add_tail(&msg->queue, &master->queue);
1425         if (!master->busy && need_pump)
1426                 queue_kthread_work(&master->kworker, &master->pump_messages);
1427
1428         spin_unlock_irqrestore(&master->queue_lock, flags);
1429         return 0;
1430 }
1431
1432 /**
1433  * spi_queued_transfer - transfer function for queued transfers
1434  * @spi: spi device which is requesting transfer
1435  * @msg: spi message which is to handled is queued to driver queue
1436  *
1437  * Return: zero on success, else a negative error code.
1438  */
1439 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1440 {
1441         return __spi_queued_transfer(spi, msg, true);
1442 }
1443
1444 static int spi_master_initialize_queue(struct spi_master *master)
1445 {
1446         int ret;
1447
1448         master->transfer = spi_queued_transfer;
1449         if (!master->transfer_one_message)
1450                 master->transfer_one_message = spi_transfer_one_message;
1451
1452         /* Initialize and start queue */
1453         ret = spi_init_queue(master);
1454         if (ret) {
1455                 dev_err(&master->dev, "problem initializing queue\n");
1456                 goto err_init_queue;
1457         }
1458         master->queued = true;
1459         ret = spi_start_queue(master);
1460         if (ret) {
1461                 dev_err(&master->dev, "problem starting queue\n");
1462                 goto err_start_queue;
1463         }
1464
1465         return 0;
1466
1467 err_start_queue:
1468         spi_destroy_queue(master);
1469 err_init_queue:
1470         return ret;
1471 }
1472
1473 /*-------------------------------------------------------------------------*/
1474
1475 #if defined(CONFIG_OF)
1476 static struct spi_device *
1477 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1478 {
1479         struct spi_device *spi;
1480         int rc;
1481         u32 value;
1482
1483         /* Alloc an spi_device */
1484         spi = spi_alloc_device(master);
1485         if (!spi) {
1486                 dev_err(&master->dev, "spi_device alloc error for %s\n",
1487                         nc->full_name);
1488                 rc = -ENOMEM;
1489                 goto err_out;
1490         }
1491
1492         /* Select device driver */
1493         rc = of_modalias_node(nc, spi->modalias,
1494                                 sizeof(spi->modalias));
1495         if (rc < 0) {
1496                 dev_err(&master->dev, "cannot find modalias for %s\n",
1497                         nc->full_name);
1498                 goto err_out;
1499         }
1500
1501         /* Device address */
1502         rc = of_property_read_u32(nc, "reg", &value);
1503         if (rc) {
1504                 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1505                         nc->full_name, rc);
1506                 goto err_out;
1507         }
1508         spi->chip_select = value;
1509
1510         /* Mode (clock phase/polarity/etc.) */
1511         if (of_find_property(nc, "spi-cpha", NULL))
1512                 spi->mode |= SPI_CPHA;
1513         if (of_find_property(nc, "spi-cpol", NULL))
1514                 spi->mode |= SPI_CPOL;
1515         if (of_find_property(nc, "spi-cs-high", NULL))
1516                 spi->mode |= SPI_CS_HIGH;
1517         if (of_find_property(nc, "spi-3wire", NULL))
1518                 spi->mode |= SPI_3WIRE;
1519         if (of_find_property(nc, "spi-lsb-first", NULL))
1520                 spi->mode |= SPI_LSB_FIRST;
1521
1522         /* Device DUAL/QUAD mode */
1523         if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1524                 switch (value) {
1525                 case 1:
1526                         break;
1527                 case 2:
1528                         spi->mode |= SPI_TX_DUAL;
1529                         break;
1530                 case 4:
1531                         spi->mode |= SPI_TX_QUAD;
1532                         break;
1533                 default:
1534                         dev_warn(&master->dev,
1535                                 "spi-tx-bus-width %d not supported\n",
1536                                 value);
1537                         break;
1538                 }
1539         }
1540
1541         if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1542                 switch (value) {
1543                 case 1:
1544                         break;
1545                 case 2:
1546                         spi->mode |= SPI_RX_DUAL;
1547                         break;
1548                 case 4:
1549                         spi->mode |= SPI_RX_QUAD;
1550                         break;
1551                 default:
1552                         dev_warn(&master->dev,
1553                                 "spi-rx-bus-width %d not supported\n",
1554                                 value);
1555                         break;
1556                 }
1557         }
1558
1559         /* Device speed */
1560         rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1561         if (rc) {
1562                 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1563                         nc->full_name, rc);
1564                 goto err_out;
1565         }
1566         spi->max_speed_hz = value;
1567
1568         /* Store a pointer to the node in the device structure */
1569         of_node_get(nc);
1570         spi->dev.of_node = nc;
1571
1572         /* Register the new device */
1573         rc = spi_add_device(spi);
1574         if (rc) {
1575                 dev_err(&master->dev, "spi_device register error %s\n",
1576                         nc->full_name);
1577                 goto err_out;
1578         }
1579
1580         return spi;
1581
1582 err_out:
1583         spi_dev_put(spi);
1584         return ERR_PTR(rc);
1585 }
1586
1587 /**
1588  * of_register_spi_devices() - Register child devices onto the SPI bus
1589  * @master:     Pointer to spi_master device
1590  *
1591  * Registers an spi_device for each child node of master node which has a 'reg'
1592  * property.
1593  */
1594 static void of_register_spi_devices(struct spi_master *master)
1595 {
1596         struct spi_device *spi;
1597         struct device_node *nc;
1598
1599         if (!master->dev.of_node)
1600                 return;
1601
1602         for_each_available_child_of_node(master->dev.of_node, nc) {
1603                 if (of_node_test_and_set_flag(nc, OF_POPULATED))
1604                         continue;
1605                 spi = of_register_spi_device(master, nc);
1606                 if (IS_ERR(spi))
1607                         dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1608                                 nc->full_name);
1609         }
1610 }
1611 #else
1612 static void of_register_spi_devices(struct spi_master *master) { }
1613 #endif
1614
1615 #ifdef CONFIG_ACPI
1616 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1617 {
1618         struct spi_device *spi = data;
1619         struct spi_master *master = spi->master;
1620
1621         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1622                 struct acpi_resource_spi_serialbus *sb;
1623
1624                 sb = &ares->data.spi_serial_bus;
1625                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1626                         /*
1627                          * ACPI DeviceSelection numbering is handled by the
1628                          * host controller driver in Windows and can vary
1629                          * from driver to driver. In Linux we always expect
1630                          * 0 .. max - 1 so we need to ask the driver to
1631                          * translate between the two schemes.
1632                          */
1633                         if (master->fw_translate_cs) {
1634                                 int cs = master->fw_translate_cs(master,
1635                                                 sb->device_selection);
1636                                 if (cs < 0)
1637                                         return cs;
1638                                 spi->chip_select = cs;
1639                         } else {
1640                                 spi->chip_select = sb->device_selection;
1641                         }
1642
1643                         spi->max_speed_hz = sb->connection_speed;
1644
1645                         if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1646                                 spi->mode |= SPI_CPHA;
1647                         if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1648                                 spi->mode |= SPI_CPOL;
1649                         if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1650                                 spi->mode |= SPI_CS_HIGH;
1651                 }
1652         } else if (spi->irq < 0) {
1653                 struct resource r;
1654
1655                 if (acpi_dev_resource_interrupt(ares, 0, &r))
1656                         spi->irq = r.start;
1657         }
1658
1659         /* Always tell the ACPI core to skip this resource */
1660         return 1;
1661 }
1662
1663 static acpi_status acpi_register_spi_device(struct spi_master *master,
1664                                             struct acpi_device *adev)
1665 {
1666         struct list_head resource_list;
1667         struct spi_device *spi;
1668         int ret;
1669
1670         if (acpi_bus_get_status(adev) || !adev->status.present ||
1671             acpi_device_enumerated(adev))
1672                 return AE_OK;
1673
1674         spi = spi_alloc_device(master);
1675         if (!spi) {
1676                 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1677                         dev_name(&adev->dev));
1678                 return AE_NO_MEMORY;
1679         }
1680
1681         ACPI_COMPANION_SET(&spi->dev, adev);
1682         spi->irq = -1;
1683
1684         INIT_LIST_HEAD(&resource_list);
1685         ret = acpi_dev_get_resources(adev, &resource_list,
1686                                      acpi_spi_add_resource, spi);
1687         acpi_dev_free_resource_list(&resource_list);
1688
1689         if (ret < 0 || !spi->max_speed_hz) {
1690                 spi_dev_put(spi);
1691                 return AE_OK;
1692         }
1693
1694         if (spi->irq < 0)
1695                 spi->irq = acpi_dev_gpio_irq_get(adev, 0);
1696
1697         acpi_device_set_enumerated(adev);
1698
1699         adev->power.flags.ignore_parent = true;
1700         strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1701         if (spi_add_device(spi)) {
1702                 adev->power.flags.ignore_parent = false;
1703                 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1704                         dev_name(&adev->dev));
1705                 spi_dev_put(spi);
1706         }
1707
1708         return AE_OK;
1709 }
1710
1711 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1712                                        void *data, void **return_value)
1713 {
1714         struct spi_master *master = data;
1715         struct acpi_device *adev;
1716
1717         if (acpi_bus_get_device(handle, &adev))
1718                 return AE_OK;
1719
1720         return acpi_register_spi_device(master, adev);
1721 }
1722
1723 static void acpi_register_spi_devices(struct spi_master *master)
1724 {
1725         acpi_status status;
1726         acpi_handle handle;
1727
1728         handle = ACPI_HANDLE(master->dev.parent);
1729         if (!handle)
1730                 return;
1731
1732         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1733                                      acpi_spi_add_device, NULL,
1734                                      master, NULL);
1735         if (ACPI_FAILURE(status))
1736                 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1737 }
1738 #else
1739 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1740 #endif /* CONFIG_ACPI */
1741
1742 static void spi_master_release(struct device *dev)
1743 {
1744         struct spi_master *master;
1745
1746         master = container_of(dev, struct spi_master, dev);
1747         kfree(master);
1748 }
1749
1750 static struct class spi_master_class = {
1751         .name           = "spi_master",
1752         .owner          = THIS_MODULE,
1753         .dev_release    = spi_master_release,
1754         .dev_groups     = spi_master_groups,
1755 };
1756
1757
1758 /**
1759  * spi_alloc_master - allocate SPI master controller
1760  * @dev: the controller, possibly using the platform_bus
1761  * @size: how much zeroed driver-private data to allocate; the pointer to this
1762  *      memory is in the driver_data field of the returned device,
1763  *      accessible with spi_master_get_devdata().
1764  * Context: can sleep
1765  *
1766  * This call is used only by SPI master controller drivers, which are the
1767  * only ones directly touching chip registers.  It's how they allocate
1768  * an spi_master structure, prior to calling spi_register_master().
1769  *
1770  * This must be called from context that can sleep.
1771  *
1772  * The caller is responsible for assigning the bus number and initializing
1773  * the master's methods before calling spi_register_master(); and (after errors
1774  * adding the device) calling spi_master_put() to prevent a memory leak.
1775  *
1776  * Return: the SPI master structure on success, else NULL.
1777  */
1778 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1779 {
1780         struct spi_master       *master;
1781
1782         if (!dev)
1783                 return NULL;
1784
1785         master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1786         if (!master)
1787                 return NULL;
1788
1789         device_initialize(&master->dev);
1790         master->bus_num = -1;
1791         master->num_chipselect = 1;
1792         master->dev.class = &spi_master_class;
1793         master->dev.parent = dev;
1794         pm_suspend_ignore_children(&master->dev, true);
1795         spi_master_set_devdata(master, &master[1]);
1796
1797         return master;
1798 }
1799 EXPORT_SYMBOL_GPL(spi_alloc_master);
1800
1801 #ifdef CONFIG_OF
1802 static int of_spi_register_master(struct spi_master *master)
1803 {
1804         int nb, i, *cs;
1805         struct device_node *np = master->dev.of_node;
1806
1807         if (!np)
1808                 return 0;
1809
1810         nb = of_gpio_named_count(np, "cs-gpios");
1811         master->num_chipselect = max_t(int, nb, master->num_chipselect);
1812
1813         /* Return error only for an incorrectly formed cs-gpios property */
1814         if (nb == 0 || nb == -ENOENT)
1815                 return 0;
1816         else if (nb < 0)
1817                 return nb;
1818
1819         cs = devm_kzalloc(&master->dev,
1820                           sizeof(int) * master->num_chipselect,
1821                           GFP_KERNEL);
1822         master->cs_gpios = cs;
1823
1824         if (!master->cs_gpios)
1825                 return -ENOMEM;
1826
1827         for (i = 0; i < master->num_chipselect; i++)
1828                 cs[i] = -ENOENT;
1829
1830         for (i = 0; i < nb; i++)
1831                 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1832
1833         return 0;
1834 }
1835 #else
1836 static int of_spi_register_master(struct spi_master *master)
1837 {
1838         return 0;
1839 }
1840 #endif
1841
1842 /**
1843  * spi_register_master - register SPI master controller
1844  * @master: initialized master, originally from spi_alloc_master()
1845  * Context: can sleep
1846  *
1847  * SPI master controllers connect to their drivers using some non-SPI bus,
1848  * such as the platform bus.  The final stage of probe() in that code
1849  * includes calling spi_register_master() to hook up to this SPI bus glue.
1850  *
1851  * SPI controllers use board specific (often SOC specific) bus numbers,
1852  * and board-specific addressing for SPI devices combines those numbers
1853  * with chip select numbers.  Since SPI does not directly support dynamic
1854  * device identification, boards need configuration tables telling which
1855  * chip is at which address.
1856  *
1857  * This must be called from context that can sleep.  It returns zero on
1858  * success, else a negative error code (dropping the master's refcount).
1859  * After a successful return, the caller is responsible for calling
1860  * spi_unregister_master().
1861  *
1862  * Return: zero on success, else a negative error code.
1863  */
1864 int spi_register_master(struct spi_master *master)
1865 {
1866         static atomic_t         dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1867         struct device           *dev = master->dev.parent;
1868         struct boardinfo        *bi;
1869         int                     status = -ENODEV;
1870         int                     dynamic = 0;
1871
1872         if (!dev)
1873                 return -ENODEV;
1874
1875         status = of_spi_register_master(master);
1876         if (status)
1877                 return status;
1878
1879         /* even if it's just one always-selected device, there must
1880          * be at least one chipselect
1881          */
1882         if (master->num_chipselect == 0)
1883                 return -EINVAL;
1884
1885         if ((master->bus_num < 0) && master->dev.of_node)
1886                 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1887
1888         /* convention:  dynamically assigned bus IDs count down from the max */
1889         if (master->bus_num < 0) {
1890                 /* FIXME switch to an IDR based scheme, something like
1891                  * I2C now uses, so we can't run out of "dynamic" IDs
1892                  */
1893                 master->bus_num = atomic_dec_return(&dyn_bus_id);
1894                 dynamic = 1;
1895         }
1896
1897         INIT_LIST_HEAD(&master->queue);
1898         spin_lock_init(&master->queue_lock);
1899         spin_lock_init(&master->bus_lock_spinlock);
1900         mutex_init(&master->bus_lock_mutex);
1901         mutex_init(&master->io_mutex);
1902         master->bus_lock_flag = 0;
1903         init_completion(&master->xfer_completion);
1904         if (!master->max_dma_len)
1905                 master->max_dma_len = INT_MAX;
1906
1907         /* register the device, then userspace will see it.
1908          * registration fails if the bus ID is in use.
1909          */
1910         dev_set_name(&master->dev, "spi%u", master->bus_num);
1911         status = device_add(&master->dev);
1912         if (status < 0)
1913                 goto done;
1914         dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1915                         dynamic ? " (dynamic)" : "");
1916
1917         /* If we're using a queued driver, start the queue */
1918         if (master->transfer)
1919                 dev_info(dev, "master is unqueued, this is deprecated\n");
1920         else {
1921                 status = spi_master_initialize_queue(master);
1922                 if (status) {
1923                         device_del(&master->dev);
1924                         goto done;
1925                 }
1926         }
1927         /* add statistics */
1928         spin_lock_init(&master->statistics.lock);
1929
1930         mutex_lock(&board_lock);
1931         list_add_tail(&master->list, &spi_master_list);
1932         list_for_each_entry(bi, &board_list, list)
1933                 spi_match_master_to_boardinfo(master, &bi->board_info);
1934         mutex_unlock(&board_lock);
1935
1936         /* Register devices from the device tree and ACPI */
1937         of_register_spi_devices(master);
1938         acpi_register_spi_devices(master);
1939 done:
1940         return status;
1941 }
1942 EXPORT_SYMBOL_GPL(spi_register_master);
1943
1944 static void devm_spi_unregister(struct device *dev, void *res)
1945 {
1946         spi_unregister_master(*(struct spi_master **)res);
1947 }
1948
1949 /**
1950  * dev_spi_register_master - register managed SPI master controller
1951  * @dev:    device managing SPI master
1952  * @master: initialized master, originally from spi_alloc_master()
1953  * Context: can sleep
1954  *
1955  * Register a SPI device as with spi_register_master() which will
1956  * automatically be unregister
1957  *
1958  * Return: zero on success, else a negative error code.
1959  */
1960 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1961 {
1962         struct spi_master **ptr;
1963         int ret;
1964
1965         ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1966         if (!ptr)
1967                 return -ENOMEM;
1968
1969         ret = spi_register_master(master);
1970         if (!ret) {
1971                 *ptr = master;
1972                 devres_add(dev, ptr);
1973         } else {
1974                 devres_free(ptr);
1975         }
1976
1977         return ret;
1978 }
1979 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1980
1981 static int __unregister(struct device *dev, void *null)
1982 {
1983         spi_unregister_device(to_spi_device(dev));
1984         return 0;
1985 }
1986
1987 /**
1988  * spi_unregister_master - unregister SPI master controller
1989  * @master: the master being unregistered
1990  * Context: can sleep
1991  *
1992  * This call is used only by SPI master controller drivers, which are the
1993  * only ones directly touching chip registers.
1994  *
1995  * This must be called from context that can sleep.
1996  */
1997 void spi_unregister_master(struct spi_master *master)
1998 {
1999         int dummy;
2000
2001         if (master->queued) {
2002                 if (spi_destroy_queue(master))
2003                         dev_err(&master->dev, "queue remove failed\n");
2004         }
2005
2006         mutex_lock(&board_lock);
2007         list_del(&master->list);
2008         mutex_unlock(&board_lock);
2009
2010         dummy = device_for_each_child(&master->dev, NULL, __unregister);
2011         device_unregister(&master->dev);
2012 }
2013 EXPORT_SYMBOL_GPL(spi_unregister_master);
2014
2015 int spi_master_suspend(struct spi_master *master)
2016 {
2017         int ret;
2018
2019         /* Basically no-ops for non-queued masters */
2020         if (!master->queued)
2021                 return 0;
2022
2023         ret = spi_stop_queue(master);
2024         if (ret)
2025                 dev_err(&master->dev, "queue stop failed\n");
2026
2027         return ret;
2028 }
2029 EXPORT_SYMBOL_GPL(spi_master_suspend);
2030
2031 int spi_master_resume(struct spi_master *master)
2032 {
2033         int ret;
2034
2035         if (!master->queued)
2036                 return 0;
2037
2038         ret = spi_start_queue(master);
2039         if (ret)
2040                 dev_err(&master->dev, "queue restart failed\n");
2041
2042         return ret;
2043 }
2044 EXPORT_SYMBOL_GPL(spi_master_resume);
2045
2046 static int __spi_master_match(struct device *dev, const void *data)
2047 {
2048         struct spi_master *m;
2049         const u16 *bus_num = data;
2050
2051         m = container_of(dev, struct spi_master, dev);
2052         return m->bus_num == *bus_num;
2053 }
2054
2055 /**
2056  * spi_busnum_to_master - look up master associated with bus_num
2057  * @bus_num: the master's bus number
2058  * Context: can sleep
2059  *
2060  * This call may be used with devices that are registered after
2061  * arch init time.  It returns a refcounted pointer to the relevant
2062  * spi_master (which the caller must release), or NULL if there is
2063  * no such master registered.
2064  *
2065  * Return: the SPI master structure on success, else NULL.
2066  */
2067 struct spi_master *spi_busnum_to_master(u16 bus_num)
2068 {
2069         struct device           *dev;
2070         struct spi_master       *master = NULL;
2071
2072         dev = class_find_device(&spi_master_class, NULL, &bus_num,
2073                                 __spi_master_match);
2074         if (dev)
2075                 master = container_of(dev, struct spi_master, dev);
2076         /* reference got in class_find_device */
2077         return master;
2078 }
2079 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
2080
2081 /*-------------------------------------------------------------------------*/
2082
2083 /* Core methods for SPI resource management */
2084
2085 /**
2086  * spi_res_alloc - allocate a spi resource that is life-cycle managed
2087  *                 during the processing of a spi_message while using
2088  *                 spi_transfer_one
2089  * @spi:     the spi device for which we allocate memory
2090  * @release: the release code to execute for this resource
2091  * @size:    size to alloc and return
2092  * @gfp:     GFP allocation flags
2093  *
2094  * Return: the pointer to the allocated data
2095  *
2096  * This may get enhanced in the future to allocate from a memory pool
2097  * of the @spi_device or @spi_master to avoid repeated allocations.
2098  */
2099 void *spi_res_alloc(struct spi_device *spi,
2100                     spi_res_release_t release,
2101                     size_t size, gfp_t gfp)
2102 {
2103         struct spi_res *sres;
2104
2105         sres = kzalloc(sizeof(*sres) + size, gfp);
2106         if (!sres)
2107                 return NULL;
2108
2109         INIT_LIST_HEAD(&sres->entry);
2110         sres->release = release;
2111
2112         return sres->data;
2113 }
2114 EXPORT_SYMBOL_GPL(spi_res_alloc);
2115
2116 /**
2117  * spi_res_free - free an spi resource
2118  * @res: pointer to the custom data of a resource
2119  *
2120  */
2121 void spi_res_free(void *res)
2122 {
2123         struct spi_res *sres = container_of(res, struct spi_res, data);
2124
2125         if (!res)
2126                 return;
2127
2128         WARN_ON(!list_empty(&sres->entry));
2129         kfree(sres);
2130 }
2131 EXPORT_SYMBOL_GPL(spi_res_free);
2132
2133 /**
2134  * spi_res_add - add a spi_res to the spi_message
2135  * @message: the spi message
2136  * @res:     the spi_resource
2137  */
2138 void spi_res_add(struct spi_message *message, void *res)
2139 {
2140         struct spi_res *sres = container_of(res, struct spi_res, data);
2141
2142         WARN_ON(!list_empty(&sres->entry));
2143         list_add_tail(&sres->entry, &message->resources);
2144 }
2145 EXPORT_SYMBOL_GPL(spi_res_add);
2146
2147 /**
2148  * spi_res_release - release all spi resources for this message
2149  * @master:  the @spi_master
2150  * @message: the @spi_message
2151  */
2152 void spi_res_release(struct spi_master *master,
2153                      struct spi_message *message)
2154 {
2155         struct spi_res *res;
2156
2157         while (!list_empty(&message->resources)) {
2158                 res = list_last_entry(&message->resources,
2159                                       struct spi_res, entry);
2160
2161                 if (res->release)
2162                         res->release(master, message, res->data);
2163
2164                 list_del(&res->entry);
2165
2166                 kfree(res);
2167         }
2168 }
2169 EXPORT_SYMBOL_GPL(spi_res_release);
2170
2171 /*-------------------------------------------------------------------------*/
2172
2173 /* Core methods for spi_message alterations */
2174
2175 static void __spi_replace_transfers_release(struct spi_master *master,
2176                                             struct spi_message *msg,
2177                                             void *res)
2178 {
2179         struct spi_replaced_transfers *rxfer = res;
2180         size_t i;
2181
2182         /* call extra callback if requested */
2183         if (rxfer->release)
2184                 rxfer->release(master, msg, res);
2185
2186         /* insert replaced transfers back into the message */
2187         list_splice(&rxfer->replaced_transfers, rxfer->replaced_after);
2188
2189         /* remove the formerly inserted entries */
2190         for (i = 0; i < rxfer->inserted; i++)
2191                 list_del(&rxfer->inserted_transfers[i].transfer_list);
2192 }
2193
2194 /**
2195  * spi_replace_transfers - replace transfers with several transfers
2196  *                         and register change with spi_message.resources
2197  * @msg:           the spi_message we work upon
2198  * @xfer_first:    the first spi_transfer we want to replace
2199  * @remove:        number of transfers to remove
2200  * @insert:        the number of transfers we want to insert instead
2201  * @release:       extra release code necessary in some circumstances
2202  * @extradatasize: extra data to allocate (with alignment guarantees
2203  *                 of struct @spi_transfer)
2204  * @gfp:           gfp flags
2205  *
2206  * Returns: pointer to @spi_replaced_transfers,
2207  *          PTR_ERR(...) in case of errors.
2208  */
2209 struct spi_replaced_transfers *spi_replace_transfers(
2210         struct spi_message *msg,
2211         struct spi_transfer *xfer_first,
2212         size_t remove,
2213         size_t insert,
2214         spi_replaced_release_t release,
2215         size_t extradatasize,
2216         gfp_t gfp)
2217 {
2218         struct spi_replaced_transfers *rxfer;
2219         struct spi_transfer *xfer;
2220         size_t i;
2221
2222         /* allocate the structure using spi_res */
2223         rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
2224                               insert * sizeof(struct spi_transfer)
2225                               + sizeof(struct spi_replaced_transfers)
2226                               + extradatasize,
2227                               gfp);
2228         if (!rxfer)
2229                 return ERR_PTR(-ENOMEM);
2230
2231         /* the release code to invoke before running the generic release */
2232         rxfer->release = release;
2233
2234         /* assign extradata */
2235         if (extradatasize)
2236                 rxfer->extradata =
2237                         &rxfer->inserted_transfers[insert];
2238
2239         /* init the replaced_transfers list */
2240         INIT_LIST_HEAD(&rxfer->replaced_transfers);
2241
2242         /* assign the list_entry after which we should reinsert
2243          * the @replaced_transfers - it may be spi_message.messages!
2244          */
2245         rxfer->replaced_after = xfer_first->transfer_list.prev;
2246
2247         /* remove the requested number of transfers */
2248         for (i = 0; i < remove; i++) {
2249                 /* if the entry after replaced_after it is msg->transfers
2250                  * then we have been requested to remove more transfers
2251                  * than are in the list
2252                  */
2253                 if (rxfer->replaced_after->next == &msg->transfers) {
2254                         dev_err(&msg->spi->dev,
2255                                 "requested to remove more spi_transfers than are available\n");
2256                         /* insert replaced transfers back into the message */
2257                         list_splice(&rxfer->replaced_transfers,
2258                                     rxfer->replaced_after);
2259
2260                         /* free the spi_replace_transfer structure */
2261                         spi_res_free(rxfer);
2262
2263                         /* and return with an error */
2264                         return ERR_PTR(-EINVAL);
2265                 }
2266
2267                 /* remove the entry after replaced_after from list of
2268                  * transfers and add it to list of replaced_transfers
2269                  */
2270                 list_move_tail(rxfer->replaced_after->next,
2271                                &rxfer->replaced_transfers);
2272         }
2273
2274         /* create copy of the given xfer with identical settings
2275          * based on the first transfer to get removed
2276          */
2277         for (i = 0; i < insert; i++) {
2278                 /* we need to run in reverse order */
2279                 xfer = &rxfer->inserted_transfers[insert - 1 - i];
2280
2281                 /* copy all spi_transfer data */
2282                 memcpy(xfer, xfer_first, sizeof(*xfer));
2283
2284                 /* add to list */
2285                 list_add(&xfer->transfer_list, rxfer->replaced_after);
2286
2287                 /* clear cs_change and delay_usecs for all but the last */
2288                 if (i) {
2289                         xfer->cs_change = false;
2290                         xfer->delay_usecs = 0;
2291                 }
2292         }
2293
2294         /* set up inserted */
2295         rxfer->inserted = insert;
2296
2297         /* and register it with spi_res/spi_message */
2298         spi_res_add(msg, rxfer);
2299
2300         return rxfer;
2301 }
2302 EXPORT_SYMBOL_GPL(spi_replace_transfers);
2303
2304 static int __spi_split_transfer_maxsize(struct spi_master *master,
2305                                         struct spi_message *msg,
2306                                         struct spi_transfer **xferp,
2307                                         size_t maxsize,
2308                                         gfp_t gfp)
2309 {
2310         struct spi_transfer *xfer = *xferp, *xfers;
2311         struct spi_replaced_transfers *srt;
2312         size_t offset;
2313         size_t count, i;
2314
2315         /* warn once about this fact that we are splitting a transfer */
2316         dev_warn_once(&msg->spi->dev,
2317                       "spi_transfer of length %i exceed max length of %zu - needed to split transfers\n",
2318                       xfer->len, maxsize);
2319
2320         /* calculate how many we have to replace */
2321         count = DIV_ROUND_UP(xfer->len, maxsize);
2322
2323         /* create replacement */
2324         srt = spi_replace_transfers(msg, xfer, 1, count, NULL, 0, gfp);
2325         if (IS_ERR(srt))
2326                 return PTR_ERR(srt);
2327         xfers = srt->inserted_transfers;
2328
2329         /* now handle each of those newly inserted spi_transfers
2330          * note that the replacements spi_transfers all are preset
2331          * to the same values as *xferp, so tx_buf, rx_buf and len
2332          * are all identical (as well as most others)
2333          * so we just have to fix up len and the pointers.
2334          *
2335          * this also includes support for the depreciated
2336          * spi_message.is_dma_mapped interface
2337          */
2338
2339         /* the first transfer just needs the length modified, so we
2340          * run it outside the loop
2341          */
2342         xfers[0].len = min_t(size_t, maxsize, xfer[0].len);
2343
2344         /* all the others need rx_buf/tx_buf also set */
2345         for (i = 1, offset = maxsize; i < count; offset += maxsize, i++) {
2346                 /* update rx_buf, tx_buf and dma */
2347                 if (xfers[i].rx_buf)
2348                         xfers[i].rx_buf += offset;
2349                 if (xfers[i].rx_dma)
2350                         xfers[i].rx_dma += offset;
2351                 if (xfers[i].tx_buf)
2352                         xfers[i].tx_buf += offset;
2353                 if (xfers[i].tx_dma)
2354                         xfers[i].tx_dma += offset;
2355
2356                 /* update length */
2357                 xfers[i].len = min(maxsize, xfers[i].len - offset);
2358         }
2359
2360         /* we set up xferp to the last entry we have inserted,
2361          * so that we skip those already split transfers
2362          */
2363         *xferp = &xfers[count - 1];
2364
2365         /* increment statistics counters */
2366         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2367                                        transfers_split_maxsize);
2368         SPI_STATISTICS_INCREMENT_FIELD(&msg->spi->statistics,
2369                                        transfers_split_maxsize);
2370
2371         return 0;
2372 }
2373
2374 /**
2375  * spi_split_tranfers_maxsize - split spi transfers into multiple transfers
2376  *                              when an individual transfer exceeds a
2377  *                              certain size
2378  * @master:    the @spi_master for this transfer
2379  * @msg:   the @spi_message to transform
2380  * @maxsize:  the maximum when to apply this
2381  * @gfp: GFP allocation flags
2382  *
2383  * Return: status of transformation
2384  */
2385 int spi_split_transfers_maxsize(struct spi_master *master,
2386                                 struct spi_message *msg,
2387                                 size_t maxsize,
2388                                 gfp_t gfp)
2389 {
2390         struct spi_transfer *xfer;
2391         int ret;
2392
2393         /* iterate over the transfer_list,
2394          * but note that xfer is advanced to the last transfer inserted
2395          * to avoid checking sizes again unnecessarily (also xfer does
2396          * potentiall belong to a different list by the time the
2397          * replacement has happened
2398          */
2399         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
2400                 if (xfer->len > maxsize) {
2401                         ret = __spi_split_transfer_maxsize(
2402                                 master, msg, &xfer, maxsize, gfp);
2403                         if (ret)
2404                                 return ret;
2405                 }
2406         }
2407
2408         return 0;
2409 }
2410 EXPORT_SYMBOL_GPL(spi_split_transfers_maxsize);
2411
2412 /*-------------------------------------------------------------------------*/
2413
2414 /* Core methods for SPI master protocol drivers.  Some of the
2415  * other core methods are currently defined as inline functions.
2416  */
2417
2418 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2419 {
2420         if (master->bits_per_word_mask) {
2421                 /* Only 32 bits fit in the mask */
2422                 if (bits_per_word > 32)
2423                         return -EINVAL;
2424                 if (!(master->bits_per_word_mask &
2425                                 SPI_BPW_MASK(bits_per_word)))
2426                         return -EINVAL;
2427         }
2428
2429         return 0;
2430 }
2431
2432 /**
2433  * spi_setup - setup SPI mode and clock rate
2434  * @spi: the device whose settings are being modified
2435  * Context: can sleep, and no requests are queued to the device
2436  *
2437  * SPI protocol drivers may need to update the transfer mode if the
2438  * device doesn't work with its default.  They may likewise need
2439  * to update clock rates or word sizes from initial values.  This function
2440  * changes those settings, and must be called from a context that can sleep.
2441  * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2442  * effect the next time the device is selected and data is transferred to
2443  * or from it.  When this function returns, the spi device is deselected.
2444  *
2445  * Note that this call will fail if the protocol driver specifies an option
2446  * that the underlying controller or its driver does not support.  For
2447  * example, not all hardware supports wire transfers using nine bit words,
2448  * LSB-first wire encoding, or active-high chipselects.
2449  *
2450  * Return: zero on success, else a negative error code.
2451  */
2452 int spi_setup(struct spi_device *spi)
2453 {
2454         unsigned        bad_bits, ugly_bits;
2455         int             status;
2456
2457         /* check mode to prevent that DUAL and QUAD set at the same time
2458          */
2459         if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2460                 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2461                 dev_err(&spi->dev,
2462                 "setup: can not select dual and quad at the same time\n");
2463                 return -EINVAL;
2464         }
2465         /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2466          */
2467         if ((spi->mode & SPI_3WIRE) && (spi->mode &
2468                 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2469                 return -EINVAL;
2470         /* help drivers fail *cleanly* when they need options
2471          * that aren't supported with their current master
2472          */
2473         bad_bits = spi->mode & ~spi->master->mode_bits;
2474         ugly_bits = bad_bits &
2475                     (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2476         if (ugly_bits) {
2477                 dev_warn(&spi->dev,
2478                          "setup: ignoring unsupported mode bits %x\n",
2479                          ugly_bits);
2480                 spi->mode &= ~ugly_bits;
2481                 bad_bits &= ~ugly_bits;
2482         }
2483         if (bad_bits) {
2484                 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2485                         bad_bits);
2486                 return -EINVAL;
2487         }
2488
2489         if (!spi->bits_per_word)
2490                 spi->bits_per_word = 8;
2491
2492         status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2493         if (status)
2494                 return status;
2495
2496         if (!spi->max_speed_hz)
2497                 spi->max_speed_hz = spi->master->max_speed_hz;
2498
2499         if (spi->master->setup)
2500                 status = spi->master->setup(spi);
2501
2502         spi_set_cs(spi, false);
2503
2504         dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2505                         (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2506                         (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2507                         (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2508                         (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2509                         (spi->mode & SPI_LOOP) ? "loopback, " : "",
2510                         spi->bits_per_word, spi->max_speed_hz,
2511                         status);
2512
2513         return status;
2514 }
2515 EXPORT_SYMBOL_GPL(spi_setup);
2516
2517 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2518 {
2519         struct spi_master *master = spi->master;
2520         struct spi_transfer *xfer;
2521         int w_size;
2522
2523         if (list_empty(&message->transfers))
2524                 return -EINVAL;
2525
2526         /* Half-duplex links include original MicroWire, and ones with
2527          * only one data pin like SPI_3WIRE (switches direction) or where
2528          * either MOSI or MISO is missing.  They can also be caused by
2529          * software limitations.
2530          */
2531         if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2532                         || (spi->mode & SPI_3WIRE)) {
2533                 unsigned flags = master->flags;
2534
2535                 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2536                         if (xfer->rx_buf && xfer->tx_buf)
2537                                 return -EINVAL;
2538                         if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2539                                 return -EINVAL;
2540                         if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2541                                 return -EINVAL;
2542                 }
2543         }
2544
2545         /**
2546          * Set transfer bits_per_word and max speed as spi device default if
2547          * it is not set for this transfer.
2548          * Set transfer tx_nbits and rx_nbits as single transfer default
2549          * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2550          */
2551         message->frame_length = 0;
2552         list_for_each_entry(xfer, &message->transfers, transfer_list) {
2553                 message->frame_length += xfer->len;
2554                 if (!xfer->bits_per_word)
2555                         xfer->bits_per_word = spi->bits_per_word;
2556
2557                 if (!xfer->speed_hz)
2558                         xfer->speed_hz = spi->max_speed_hz;
2559                 if (!xfer->speed_hz)
2560                         xfer->speed_hz = master->max_speed_hz;
2561
2562                 if (master->max_speed_hz &&
2563                     xfer->speed_hz > master->max_speed_hz)
2564                         xfer->speed_hz = master->max_speed_hz;
2565
2566                 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2567                         return -EINVAL;
2568
2569                 /*
2570                  * SPI transfer length should be multiple of SPI word size
2571                  * where SPI word size should be power-of-two multiple
2572                  */
2573                 if (xfer->bits_per_word <= 8)
2574                         w_size = 1;
2575                 else if (xfer->bits_per_word <= 16)
2576                         w_size = 2;
2577                 else
2578                         w_size = 4;
2579
2580                 /* No partial transfers accepted */
2581                 if (xfer->len % w_size)
2582                         return -EINVAL;
2583
2584                 if (xfer->speed_hz && master->min_speed_hz &&
2585                     xfer->speed_hz < master->min_speed_hz)
2586                         return -EINVAL;
2587
2588                 if (xfer->tx_buf && !xfer->tx_nbits)
2589                         xfer->tx_nbits = SPI_NBITS_SINGLE;
2590                 if (xfer->rx_buf && !xfer->rx_nbits)
2591                         xfer->rx_nbits = SPI_NBITS_SINGLE;
2592                 /* check transfer tx/rx_nbits:
2593                  * 1. check the value matches one of single, dual and quad
2594                  * 2. check tx/rx_nbits match the mode in spi_device
2595                  */
2596                 if (xfer->tx_buf) {
2597                         if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2598                                 xfer->tx_nbits != SPI_NBITS_DUAL &&
2599                                 xfer->tx_nbits != SPI_NBITS_QUAD)
2600                                 return -EINVAL;
2601                         if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2602                                 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2603                                 return -EINVAL;
2604                         if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2605                                 !(spi->mode & SPI_TX_QUAD))
2606                                 return -EINVAL;
2607                 }
2608                 /* check transfer rx_nbits */
2609                 if (xfer->rx_buf) {
2610                         if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2611                                 xfer->rx_nbits != SPI_NBITS_DUAL &&
2612                                 xfer->rx_nbits != SPI_NBITS_QUAD)
2613                                 return -EINVAL;
2614                         if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2615                                 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2616                                 return -EINVAL;
2617                         if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2618                                 !(spi->mode & SPI_RX_QUAD))
2619                                 return -EINVAL;
2620                 }
2621         }
2622
2623         message->status = -EINPROGRESS;
2624
2625         return 0;
2626 }
2627
2628 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2629 {
2630         struct spi_master *master = spi->master;
2631
2632         message->spi = spi;
2633
2634         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2635         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2636
2637         trace_spi_message_submit(message);
2638
2639         return master->transfer(spi, message);
2640 }
2641
2642 /**
2643  * spi_async - asynchronous SPI transfer
2644  * @spi: device with which data will be exchanged
2645  * @message: describes the data transfers, including completion callback
2646  * Context: any (irqs may be blocked, etc)
2647  *
2648  * This call may be used in_irq and other contexts which can't sleep,
2649  * as well as from task contexts which can sleep.
2650  *
2651  * The completion callback is invoked in a context which can't sleep.
2652  * Before that invocation, the value of message->status is undefined.
2653  * When the callback is issued, message->status holds either zero (to
2654  * indicate complete success) or a negative error code.  After that
2655  * callback returns, the driver which issued the transfer request may
2656  * deallocate the associated memory; it's no longer in use by any SPI
2657  * core or controller driver code.
2658  *
2659  * Note that although all messages to a spi_device are handled in
2660  * FIFO order, messages may go to different devices in other orders.
2661  * Some device might be higher priority, or have various "hard" access
2662  * time requirements, for example.
2663  *
2664  * On detection of any fault during the transfer, processing of
2665  * the entire message is aborted, and the device is deselected.
2666  * Until returning from the associated message completion callback,
2667  * no other spi_message queued to that device will be processed.
2668  * (This rule applies equally to all the synchronous transfer calls,
2669  * which are wrappers around this core asynchronous primitive.)
2670  *
2671  * Return: zero on success, else a negative error code.
2672  */
2673 int spi_async(struct spi_device *spi, struct spi_message *message)
2674 {
2675         struct spi_master *master = spi->master;
2676         int ret;
2677         unsigned long flags;
2678
2679         ret = __spi_validate(spi, message);
2680         if (ret != 0)
2681                 return ret;
2682
2683         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2684
2685         if (master->bus_lock_flag)
2686                 ret = -EBUSY;
2687         else
2688                 ret = __spi_async(spi, message);
2689
2690         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2691
2692         return ret;
2693 }
2694 EXPORT_SYMBOL_GPL(spi_async);
2695
2696 /**
2697  * spi_async_locked - version of spi_async with exclusive bus usage
2698  * @spi: device with which data will be exchanged
2699  * @message: describes the data transfers, including completion callback
2700  * Context: any (irqs may be blocked, etc)
2701  *
2702  * This call may be used in_irq and other contexts which can't sleep,
2703  * as well as from task contexts which can sleep.
2704  *
2705  * The completion callback is invoked in a context which can't sleep.
2706  * Before that invocation, the value of message->status is undefined.
2707  * When the callback is issued, message->status holds either zero (to
2708  * indicate complete success) or a negative error code.  After that
2709  * callback returns, the driver which issued the transfer request may
2710  * deallocate the associated memory; it's no longer in use by any SPI
2711  * core or controller driver code.
2712  *
2713  * Note that although all messages to a spi_device are handled in
2714  * FIFO order, messages may go to different devices in other orders.
2715  * Some device might be higher priority, or have various "hard" access
2716  * time requirements, for example.
2717  *
2718  * On detection of any fault during the transfer, processing of
2719  * the entire message is aborted, and the device is deselected.
2720  * Until returning from the associated message completion callback,
2721  * no other spi_message queued to that device will be processed.
2722  * (This rule applies equally to all the synchronous transfer calls,
2723  * which are wrappers around this core asynchronous primitive.)
2724  *
2725  * Return: zero on success, else a negative error code.
2726  */
2727 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2728 {
2729         struct spi_master *master = spi->master;
2730         int ret;
2731         unsigned long flags;
2732
2733         ret = __spi_validate(spi, message);
2734         if (ret != 0)
2735                 return ret;
2736
2737         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2738
2739         ret = __spi_async(spi, message);
2740
2741         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2742
2743         return ret;
2744
2745 }
2746 EXPORT_SYMBOL_GPL(spi_async_locked);
2747
2748
2749 int spi_flash_read(struct spi_device *spi,
2750                    struct spi_flash_read_message *msg)
2751
2752 {
2753         struct spi_master *master = spi->master;
2754         struct device *rx_dev = NULL;
2755         int ret;
2756
2757         if ((msg->opcode_nbits == SPI_NBITS_DUAL ||
2758              msg->addr_nbits == SPI_NBITS_DUAL) &&
2759             !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2760                 return -EINVAL;
2761         if ((msg->opcode_nbits == SPI_NBITS_QUAD ||
2762              msg->addr_nbits == SPI_NBITS_QUAD) &&
2763             !(spi->mode & SPI_TX_QUAD))
2764                 return -EINVAL;
2765         if (msg->data_nbits == SPI_NBITS_DUAL &&
2766             !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2767                 return -EINVAL;
2768         if (msg->data_nbits == SPI_NBITS_QUAD &&
2769             !(spi->mode &  SPI_RX_QUAD))
2770                 return -EINVAL;
2771
2772         if (master->auto_runtime_pm) {
2773                 ret = pm_runtime_get_sync(master->dev.parent);
2774                 if (ret < 0) {
2775                         dev_err(&master->dev, "Failed to power device: %d\n",
2776                                 ret);
2777                         return ret;
2778                 }
2779         }
2780
2781         mutex_lock(&master->bus_lock_mutex);
2782         mutex_lock(&master->io_mutex);
2783         if (master->dma_rx) {
2784                 rx_dev = master->dma_rx->device->dev;
2785                 ret = spi_map_buf(master, rx_dev, &msg->rx_sg,
2786                                   msg->buf, msg->len,
2787                                   DMA_FROM_DEVICE);
2788                 if (!ret)
2789                         msg->cur_msg_mapped = true;
2790         }
2791         ret = master->spi_flash_read(spi, msg);
2792         if (msg->cur_msg_mapped)
2793                 spi_unmap_buf(master, rx_dev, &msg->rx_sg,
2794                               DMA_FROM_DEVICE);
2795         mutex_unlock(&master->io_mutex);
2796         mutex_unlock(&master->bus_lock_mutex);
2797
2798         if (master->auto_runtime_pm)
2799                 pm_runtime_put(master->dev.parent);
2800
2801         return ret;
2802 }
2803 EXPORT_SYMBOL_GPL(spi_flash_read);
2804
2805 /*-------------------------------------------------------------------------*/
2806
2807 /* Utility methods for SPI master protocol drivers, layered on
2808  * top of the core.  Some other utility methods are defined as
2809  * inline functions.
2810  */
2811
2812 static void spi_complete(void *arg)
2813 {
2814         complete(arg);
2815 }
2816
2817 static int __spi_sync(struct spi_device *spi, struct spi_message *message)
2818 {
2819         DECLARE_COMPLETION_ONSTACK(done);
2820         int status;
2821         struct spi_master *master = spi->master;
2822         unsigned long flags;
2823
2824         status = __spi_validate(spi, message);
2825         if (status != 0)
2826                 return status;
2827
2828         message->complete = spi_complete;
2829         message->context = &done;
2830         message->spi = spi;
2831
2832         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2833         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2834
2835         /* If we're not using the legacy transfer method then we will
2836          * try to transfer in the calling context so special case.
2837          * This code would be less tricky if we could remove the
2838          * support for driver implemented message queues.
2839          */
2840         if (master->transfer == spi_queued_transfer) {
2841                 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2842
2843                 trace_spi_message_submit(message);
2844
2845                 status = __spi_queued_transfer(spi, message, false);
2846
2847                 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2848         } else {
2849                 status = spi_async_locked(spi, message);
2850         }
2851
2852         if (status == 0) {
2853                 /* Push out the messages in the calling context if we
2854                  * can.
2855                  */
2856                 if (master->transfer == spi_queued_transfer) {
2857                         SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2858                                                        spi_sync_immediate);
2859                         SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2860                                                        spi_sync_immediate);
2861                         __spi_pump_messages(master, false);
2862                 }
2863
2864                 wait_for_completion(&done);
2865                 status = message->status;
2866         }
2867         message->context = NULL;
2868         return status;
2869 }
2870
2871 /**
2872  * spi_sync - blocking/synchronous SPI data transfers
2873  * @spi: device with which data will be exchanged
2874  * @message: describes the data transfers
2875  * Context: can sleep
2876  *
2877  * This call may only be used from a context that may sleep.  The sleep
2878  * is non-interruptible, and has no timeout.  Low-overhead controller
2879  * drivers may DMA directly into and out of the message buffers.
2880  *
2881  * Note that the SPI device's chip select is active during the message,
2882  * and then is normally disabled between messages.  Drivers for some
2883  * frequently-used devices may want to minimize costs of selecting a chip,
2884  * by leaving it selected in anticipation that the next message will go
2885  * to the same chip.  (That may increase power usage.)
2886  *
2887  * Also, the caller is guaranteeing that the memory associated with the
2888  * message will not be freed before this call returns.
2889  *
2890  * Return: zero on success, else a negative error code.
2891  */
2892 int spi_sync(struct spi_device *spi, struct spi_message *message)
2893 {
2894         int ret;
2895
2896         mutex_lock(&spi->master->bus_lock_mutex);
2897         ret = __spi_sync(spi, message);
2898         mutex_unlock(&spi->master->bus_lock_mutex);
2899
2900         return ret;
2901 }
2902 EXPORT_SYMBOL_GPL(spi_sync);
2903
2904 /**
2905  * spi_sync_locked - version of spi_sync with exclusive bus usage
2906  * @spi: device with which data will be exchanged
2907  * @message: describes the data transfers
2908  * Context: can sleep
2909  *
2910  * This call may only be used from a context that may sleep.  The sleep
2911  * is non-interruptible, and has no timeout.  Low-overhead controller
2912  * drivers may DMA directly into and out of the message buffers.
2913  *
2914  * This call should be used by drivers that require exclusive access to the
2915  * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2916  * be released by a spi_bus_unlock call when the exclusive access is over.
2917  *
2918  * Return: zero on success, else a negative error code.
2919  */
2920 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2921 {
2922         return __spi_sync(spi, message);
2923 }
2924 EXPORT_SYMBOL_GPL(spi_sync_locked);
2925
2926 /**
2927  * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2928  * @master: SPI bus master that should be locked for exclusive bus access
2929  * Context: can sleep
2930  *
2931  * This call may only be used from a context that may sleep.  The sleep
2932  * is non-interruptible, and has no timeout.
2933  *
2934  * This call should be used by drivers that require exclusive access to the
2935  * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2936  * exclusive access is over. Data transfer must be done by spi_sync_locked
2937  * and spi_async_locked calls when the SPI bus lock is held.
2938  *
2939  * Return: always zero.
2940  */
2941 int spi_bus_lock(struct spi_master *master)
2942 {
2943         unsigned long flags;
2944
2945         mutex_lock(&master->bus_lock_mutex);
2946
2947         spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2948         master->bus_lock_flag = 1;
2949         spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2950
2951         /* mutex remains locked until spi_bus_unlock is called */
2952
2953         return 0;
2954 }
2955 EXPORT_SYMBOL_GPL(spi_bus_lock);
2956
2957 /**
2958  * spi_bus_unlock - release the lock for exclusive SPI bus usage
2959  * @master: SPI bus master that was locked for exclusive bus access
2960  * Context: can sleep
2961  *
2962  * This call may only be used from a context that may sleep.  The sleep
2963  * is non-interruptible, and has no timeout.
2964  *
2965  * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2966  * call.
2967  *
2968  * Return: always zero.
2969  */
2970 int spi_bus_unlock(struct spi_master *master)
2971 {
2972         master->bus_lock_flag = 0;
2973
2974         mutex_unlock(&master->bus_lock_mutex);
2975
2976         return 0;
2977 }
2978 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2979
2980 /* portable code must never pass more than 32 bytes */
2981 #define SPI_BUFSIZ      max(32, SMP_CACHE_BYTES)
2982
2983 static u8       *buf;
2984
2985 /**
2986  * spi_write_then_read - SPI synchronous write followed by read
2987  * @spi: device with which data will be exchanged
2988  * @txbuf: data to be written (need not be dma-safe)
2989  * @n_tx: size of txbuf, in bytes
2990  * @rxbuf: buffer into which data will be read (need not be dma-safe)
2991  * @n_rx: size of rxbuf, in bytes
2992  * Context: can sleep
2993  *
2994  * This performs a half duplex MicroWire style transaction with the
2995  * device, sending txbuf and then reading rxbuf.  The return value
2996  * is zero for success, else a negative errno status code.
2997  * This call may only be used from a context that may sleep.
2998  *
2999  * Parameters to this routine are always copied using a small buffer;
3000  * portable code should never use this for more than 32 bytes.
3001  * Performance-sensitive or bulk transfer code should instead use
3002  * spi_{async,sync}() calls with dma-safe buffers.
3003  *
3004  * Return: zero on success, else a negative error code.
3005  */
3006 int spi_write_then_read(struct spi_device *spi,
3007                 const void *txbuf, unsigned n_tx,
3008                 void *rxbuf, unsigned n_rx)
3009 {
3010         static DEFINE_MUTEX(lock);
3011
3012         int                     status;
3013         struct spi_message      message;
3014         struct spi_transfer     x[2];
3015         u8                      *local_buf;
3016
3017         /* Use preallocated DMA-safe buffer if we can.  We can't avoid
3018          * copying here, (as a pure convenience thing), but we can
3019          * keep heap costs out of the hot path unless someone else is
3020          * using the pre-allocated buffer or the transfer is too large.
3021          */
3022         if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
3023                 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
3024                                     GFP_KERNEL | GFP_DMA);
3025                 if (!local_buf)
3026                         return -ENOMEM;
3027         } else {
3028                 local_buf = buf;
3029         }
3030
3031         spi_message_init(&message);
3032         memset(x, 0, sizeof(x));
3033         if (n_tx) {
3034                 x[0].len = n_tx;
3035                 spi_message_add_tail(&x[0], &message);
3036         }
3037         if (n_rx) {
3038                 x[1].len = n_rx;
3039                 spi_message_add_tail(&x[1], &message);
3040         }
3041
3042         memcpy(local_buf, txbuf, n_tx);
3043         x[0].tx_buf = local_buf;
3044         x[1].rx_buf = local_buf + n_tx;
3045
3046         /* do the i/o */
3047         status = spi_sync(spi, &message);
3048         if (status == 0)
3049                 memcpy(rxbuf, x[1].rx_buf, n_rx);
3050
3051         if (x[0].tx_buf == buf)
3052                 mutex_unlock(&lock);
3053         else
3054                 kfree(local_buf);
3055
3056         return status;
3057 }
3058 EXPORT_SYMBOL_GPL(spi_write_then_read);
3059
3060 /*-------------------------------------------------------------------------*/
3061
3062 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
3063 static int __spi_of_device_match(struct device *dev, void *data)
3064 {
3065         return dev->of_node == data;
3066 }
3067
3068 /* must call put_device() when done with returned spi_device device */
3069 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
3070 {
3071         struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
3072                                                 __spi_of_device_match);
3073         return dev ? to_spi_device(dev) : NULL;
3074 }
3075
3076 static int __spi_of_master_match(struct device *dev, const void *data)
3077 {
3078         return dev->of_node == data;
3079 }
3080
3081 /* the spi masters are not using spi_bus, so we find it with another way */
3082 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
3083 {
3084         struct device *dev;
3085
3086         dev = class_find_device(&spi_master_class, NULL, node,
3087                                 __spi_of_master_match);
3088         if (!dev)
3089                 return NULL;
3090
3091         /* reference got in class_find_device */
3092         return container_of(dev, struct spi_master, dev);
3093 }
3094
3095 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
3096                          void *arg)
3097 {
3098         struct of_reconfig_data *rd = arg;
3099         struct spi_master *master;
3100         struct spi_device *spi;
3101
3102         switch (of_reconfig_get_state_change(action, arg)) {
3103         case OF_RECONFIG_CHANGE_ADD:
3104                 master = of_find_spi_master_by_node(rd->dn->parent);
3105                 if (master == NULL)
3106                         return NOTIFY_OK;       /* not for us */
3107
3108                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
3109                         put_device(&master->dev);
3110                         return NOTIFY_OK;
3111                 }
3112
3113                 spi = of_register_spi_device(master, rd->dn);
3114                 put_device(&master->dev);
3115
3116                 if (IS_ERR(spi)) {
3117                         pr_err("%s: failed to create for '%s'\n",
3118                                         __func__, rd->dn->full_name);
3119                         return notifier_from_errno(PTR_ERR(spi));
3120                 }
3121                 break;
3122
3123         case OF_RECONFIG_CHANGE_REMOVE:
3124                 /* already depopulated? */
3125                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
3126                         return NOTIFY_OK;
3127
3128                 /* find our device by node */
3129                 spi = of_find_spi_device_by_node(rd->dn);
3130                 if (spi == NULL)
3131                         return NOTIFY_OK;       /* no? not meant for us */
3132
3133                 /* unregister takes one ref away */
3134                 spi_unregister_device(spi);
3135
3136                 /* and put the reference of the find */
3137                 put_device(&spi->dev);
3138                 break;
3139         }
3140
3141         return NOTIFY_OK;
3142 }
3143
3144 static struct notifier_block spi_of_notifier = {
3145         .notifier_call = of_spi_notify,
3146 };
3147 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3148 extern struct notifier_block spi_of_notifier;
3149 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
3150
3151 #if IS_ENABLED(CONFIG_ACPI)
3152 static int spi_acpi_master_match(struct device *dev, const void *data)
3153 {
3154         return ACPI_COMPANION(dev->parent) == data;
3155 }
3156
3157 static int spi_acpi_device_match(struct device *dev, void *data)
3158 {
3159         return ACPI_COMPANION(dev) == data;
3160 }
3161
3162 static struct spi_master *acpi_spi_find_master_by_adev(struct acpi_device *adev)
3163 {
3164         struct device *dev;
3165
3166         dev = class_find_device(&spi_master_class, NULL, adev,
3167                                 spi_acpi_master_match);
3168         if (!dev)
3169                 return NULL;
3170
3171         return container_of(dev, struct spi_master, dev);
3172 }
3173
3174 static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
3175 {
3176         struct device *dev;
3177
3178         dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
3179
3180         return dev ? to_spi_device(dev) : NULL;
3181 }
3182
3183 static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
3184                            void *arg)
3185 {
3186         struct acpi_device *adev = arg;
3187         struct spi_master *master;
3188         struct spi_device *spi;
3189
3190         switch (value) {
3191         case ACPI_RECONFIG_DEVICE_ADD:
3192                 master = acpi_spi_find_master_by_adev(adev->parent);
3193                 if (!master)
3194                         break;
3195
3196                 acpi_register_spi_device(master, adev);
3197                 put_device(&master->dev);
3198                 break;
3199         case ACPI_RECONFIG_DEVICE_REMOVE:
3200                 if (!acpi_device_enumerated(adev))
3201                         break;
3202
3203                 spi = acpi_spi_find_device_by_adev(adev);
3204                 if (!spi)
3205                         break;
3206
3207                 spi_unregister_device(spi);
3208                 put_device(&spi->dev);
3209                 break;
3210         }
3211
3212         return NOTIFY_OK;
3213 }
3214
3215 static struct notifier_block spi_acpi_notifier = {
3216         .notifier_call = acpi_spi_notify,
3217 };
3218 #else
3219 extern struct notifier_block spi_acpi_notifier;
3220 #endif
3221
3222 static int __init spi_init(void)
3223 {
3224         int     status;
3225
3226         buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
3227         if (!buf) {
3228                 status = -ENOMEM;
3229                 goto err0;
3230         }
3231
3232         status = bus_register(&spi_bus_type);
3233         if (status < 0)
3234                 goto err1;
3235
3236         status = class_register(&spi_master_class);
3237         if (status < 0)
3238                 goto err2;
3239
3240         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
3241                 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
3242         if (IS_ENABLED(CONFIG_ACPI))
3243                 WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
3244
3245         return 0;
3246
3247 err2:
3248         bus_unregister(&spi_bus_type);
3249 err1:
3250         kfree(buf);
3251         buf = NULL;
3252 err0:
3253         return status;
3254 }
3255
3256 /* board_info is normally registered in arch_initcall(),
3257  * but even essential drivers wait till later
3258  *
3259  * REVISIT only boardinfo really needs static linking. the rest (device and
3260  * driver registration) _could_ be dynamically linked (modular) ... costs
3261  * include needing to have boardinfo data structures be much more public.
3262  */
3263 postcore_initcall(spi_init);
3264