drivers/i2c/busses/i2c-amd-mp2-pci.c

   1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
   2 /*
   3  * AMD MP2 PCIe communication driver
   4  *
   5  * Authors: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
   6  *          Elie Morisse <syniurge@gmail.com>
   7  */
   8
   9 #include <linux/dma-mapping.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/module.h>
  12 #include <linux/pci.h>
  13 #include <linux/slab.h>
  14
  15 #include "i2c-amd-mp2.h"
  16
  17 #include <linux/io-64-nonatomic-lo-hi.h>
  18
  19 static void amd_mp2_c2p_mutex_lock(struct amd_i2c_common *i2c_common)
  20 {
  21         struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
  22
  23         /* there is only one data mailbox for two i2c adapters */
  24         mutex_lock(&privdata->c2p_lock);
  25         privdata->c2p_lock_busid = i2c_common->bus_id;
  26 }
  27
  28 static void amd_mp2_c2p_mutex_unlock(struct amd_i2c_common *i2c_common)
  29 {
  30         struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
  31
  32         if (unlikely(privdata->c2p_lock_busid != i2c_common->bus_id)) {
  33                 pci_warn(privdata->pci_dev,
  34                          "bus %d attempting to unlock C2P locked by bus %d\n",
  35                          i2c_common->bus_id, privdata->c2p_lock_busid);
  36                 return;
  37         }
  38
  39         mutex_unlock(&privdata->c2p_lock);
  40 }
  41
  42 static int amd_mp2_cmd(struct amd_i2c_common *i2c_common,
  43                        union i2c_cmd_base i2c_cmd_base)
  44 {
  45         struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
  46         void __iomem *reg;
  47
  48         i2c_common->reqcmd = i2c_cmd_base.s.i2c_cmd;
  49
  50         reg = privdata->mmio + ((i2c_cmd_base.s.bus_id == 1) ?
  51                                 AMD_C2P_MSG1 : AMD_C2P_MSG0);
  52         writel(i2c_cmd_base.ul, reg);
  53
  54         return 0;
  55 }
  56
  57 int amd_mp2_bus_enable_set(struct amd_i2c_common *i2c_common, bool enable)
  58 {
  59         struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
  60         union i2c_cmd_base i2c_cmd_base;
  61
  62         pci_dbg(privdata->pci_dev, "id: %d\n", i2c_common->bus_id);
  63
  64         i2c_cmd_base.ul = 0;
  65         i2c_cmd_base.s.i2c_cmd = enable ? i2c_enable : i2c_disable;
  66         i2c_cmd_base.s.bus_id = i2c_common->bus_id;
  67         i2c_cmd_base.s.i2c_speed = i2c_common->i2c_speed;
  68
  69         amd_mp2_c2p_mutex_lock(i2c_common);
  70
  71         return amd_mp2_cmd(i2c_common, i2c_cmd_base);
  72 }
  73 EXPORT_SYMBOL_GPL(amd_mp2_bus_enable_set);
  74
  75 static void amd_mp2_cmd_rw_fill(struct amd_i2c_common *i2c_common,
  76                                 union i2c_cmd_base *i2c_cmd_base,
  77                                 enum i2c_cmd reqcmd)
  78 {
  79         i2c_cmd_base->s.i2c_cmd = reqcmd;
  80         i2c_cmd_base->s.bus_id = i2c_common->bus_id;
  81         i2c_cmd_base->s.i2c_speed = i2c_common->i2c_speed;
  82         i2c_cmd_base->s.slave_addr = i2c_common->msg->addr;
  83         i2c_cmd_base->s.length = i2c_common->msg->len;
  84 }
  85
  86 int amd_mp2_rw(struct amd_i2c_common *i2c_common, enum i2c_cmd reqcmd)
  87 {
  88         struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
  89         union i2c_cmd_base i2c_cmd_base;
  90
  91         amd_mp2_cmd_rw_fill(i2c_common, &i2c_cmd_base, reqcmd);
  92         amd_mp2_c2p_mutex_lock(i2c_common);
  93
  94         if (i2c_common->msg->len <= 32) {
  95                 i2c_cmd_base.s.mem_type = use_c2pmsg;
  96                 if (reqcmd == i2c_write)
  97                         memcpy_toio(privdata->mmio + AMD_C2P_MSG2,
  98                                     i2c_common->msg->buf,
  99                                     i2c_common->msg->len);
 100         } else {
 101                 i2c_cmd_base.s.mem_type = use_dram;
 102                 writeq((u64)i2c_common->dma_addr,
 103                        privdata->mmio + AMD_C2P_MSG2);
 104         }
 105
 106         return amd_mp2_cmd(i2c_common, i2c_cmd_base);
 107 }
 108 EXPORT_SYMBOL_GPL(amd_mp2_rw);
 109
 110 static void amd_mp2_pci_check_rw_event(struct amd_i2c_common *i2c_common)
 111 {
 112         struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
 113         struct pci_dev *pdev = privdata->pci_dev;
 114         int len = i2c_common->eventval.r.length;
 115         u32 slave_addr = i2c_common->eventval.r.slave_addr;
 116         bool err = false;
 117
 118         if (unlikely(len != i2c_common->msg->len)) {
 119                 pci_err(pdev, "length %d in event doesn't match buffer length %d!\n",
 120                         len, i2c_common->msg->len);
 121                 err = true;
 122         }
 123
 124         if (unlikely(slave_addr != i2c_common->msg->addr)) {
 125                 pci_err(pdev, "unexpected slave address %x (expected: %x)!\n",
 126                         slave_addr, i2c_common->msg->addr);
 127                 err = true;
 128         }
 129
 130         if (!err)
 131                 i2c_common->cmd_success = true;
 132 }
 133
 134 static void __amd_mp2_process_event(struct amd_i2c_common *i2c_common)
 135 {
 136         struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
 137         struct pci_dev *pdev = privdata->pci_dev;
 138         enum status_type sts = i2c_common->eventval.r.status;
 139         enum response_type res = i2c_common->eventval.r.response;
 140         int len = i2c_common->eventval.r.length;
 141
 142         if (res != command_success) {
 143                 if (res != command_failed)
 144                         pci_err(pdev, "invalid response to i2c command!\n");
 145                 return;
 146         }
 147
 148         switch (i2c_common->reqcmd) {
 149         case i2c_read:
 150                 if (sts == i2c_readcomplete_event) {
 151                         amd_mp2_pci_check_rw_event(i2c_common);
 152                         if (len <= 32)
 153                                 memcpy_fromio(i2c_common->msg->buf,
 154                                               privdata->mmio + AMD_C2P_MSG2,
 155                                               len);
 156                 } else if (sts != i2c_readfail_event) {
 157                         pci_err(pdev, "invalid i2c status after read (%d)!\n", sts);
 158                 }
 159                 break;
 160         case i2c_write:
 161                 if (sts == i2c_writecomplete_event)
 162                         amd_mp2_pci_check_rw_event(i2c_common);
 163                 else if (sts != i2c_writefail_event)
 164                         pci_err(pdev, "invalid i2c status after write (%d)!\n", sts);
 165                 break;
 166         case i2c_enable:
 167                 if (sts == i2c_busenable_complete)
 168                         i2c_common->cmd_success = true;
 169                 else if (sts != i2c_busenable_failed)
 170                         pci_err(pdev, "invalid i2c status after bus enable (%d)!\n", sts);
 171                 break;
 172         case i2c_disable:
 173                 if (sts == i2c_busdisable_complete)
 174                         i2c_common->cmd_success = true;
 175                 else if (sts != i2c_busdisable_failed)
 176                         pci_err(pdev, "invalid i2c status after bus disable (%d)!\n", sts);
 177                 break;
 178         default:
 179                 break;
 180         }
 181 }
 182
 183 void amd_mp2_process_event(struct amd_i2c_common *i2c_common)
 184 {
 185         struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
 186         struct pci_dev *pdev = privdata->pci_dev;
 187
 188         if (unlikely(i2c_common->reqcmd == i2c_none)) {
 189                 pci_warn(pdev, "received msg but no cmd was sent (bus = %d)!\n",
 190                          i2c_common->bus_id);
 191                 return;
 192         }
 193
 194         __amd_mp2_process_event(i2c_common);
 195
 196         i2c_common->reqcmd = i2c_none;
 197         amd_mp2_c2p_mutex_unlock(i2c_common);
 198 }
 199 EXPORT_SYMBOL_GPL(amd_mp2_process_event);
 200
 201 static irqreturn_t amd_mp2_irq_isr(int irq, void *dev)
 202 {
 203         struct amd_mp2_dev *privdata = dev;
 204         struct pci_dev *pdev = privdata->pci_dev;
 205         struct amd_i2c_common *i2c_common;
 206         u32 val;
 207         unsigned int bus_id;
 208         void __iomem *reg;
 209         enum irqreturn ret = IRQ_NONE;
 210
 211         for (bus_id = 0; bus_id < 2; bus_id++) {
 212                 i2c_common = privdata->busses[bus_id];
 213                 if (!i2c_common)
 214                         continue;
 215
 216                 reg = privdata->mmio + ((bus_id == 0) ?
 217                                         AMD_P2C_MSG1 : AMD_P2C_MSG2);
 218                 val = readl(reg);
 219                 if (val != 0) {
 220                         writel(0, reg);
 221                         writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
 222                         i2c_common->eventval.ul = val;
 223                         i2c_common->cmd_completion(i2c_common);
 224
 225                         ret = IRQ_HANDLED;
 226                 }
 227         }
 228
 229         if (ret != IRQ_HANDLED) {
 230                 val = readl(privdata->mmio + AMD_P2C_MSG_INTEN);
 231                 if (val != 0) {
 232                         writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
 233                         pci_warn(pdev, "received irq without message\n");
 234                         ret = IRQ_HANDLED;
 235                 }
 236         }
 237
 238         return ret;
 239 }
 240
 241 void amd_mp2_rw_timeout(struct amd_i2c_common *i2c_common)
 242 {
 243         i2c_common->reqcmd = i2c_none;
 244         amd_mp2_c2p_mutex_unlock(i2c_common);
 245 }
 246 EXPORT_SYMBOL_GPL(amd_mp2_rw_timeout);
 247
 248 int amd_mp2_register_cb(struct amd_i2c_common *i2c_common)
 249 {
 250         struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
 251         struct pci_dev *pdev = privdata->pci_dev;
 252
 253         if (i2c_common->bus_id > 1)
 254                 return -EINVAL;
 255
 256         if (privdata->busses[i2c_common->bus_id]) {
 257                 pci_err(pdev, "Bus %d already taken!\n", i2c_common->bus_id);
 258                 return -EINVAL;
 259         }
 260
 261         privdata->busses[i2c_common->bus_id] = i2c_common;
 262
 263         return 0;
 264 }
 265 EXPORT_SYMBOL_GPL(amd_mp2_register_cb);
 266
 267 int amd_mp2_unregister_cb(struct amd_i2c_common *i2c_common)
 268 {
 269         struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
 270
 271         privdata->busses[i2c_common->bus_id] = NULL;
 272
 273         return 0;
 274 }
 275 EXPORT_SYMBOL_GPL(amd_mp2_unregister_cb);
 276
 277 static void amd_mp2_clear_reg(struct amd_mp2_dev *privdata)
 278 {
 279         int reg;
 280
 281         for (reg = AMD_C2P_MSG0; reg <= AMD_C2P_MSG9; reg += 4)
 282                 writel(0, privdata->mmio + reg);
 283
 284         for (reg = AMD_P2C_MSG1; reg <= AMD_P2C_MSG2; reg += 4)
 285                 writel(0, privdata->mmio + reg);
 286 }
 287
 288 static int amd_mp2_pci_init(struct amd_mp2_dev *privdata,
 289                             struct pci_dev *pci_dev)
 290 {
 291         int rc;
 292
 293         pci_set_drvdata(pci_dev, privdata);
 294
 295         rc = pcim_enable_device(pci_dev);
 296         if (rc) {
 297                 pci_err(pci_dev, "Failed to enable MP2 PCI device\n");
 298                 goto err_pci_enable;
 299         }
 300
 301         rc = pcim_iomap_regions(pci_dev, 1 << 2, pci_name(pci_dev));
 302         if (rc) {
 303                 pci_err(pci_dev, "I/O memory remapping failed\n");
 304                 goto err_pci_enable;
 305         }
 306         privdata->mmio = pcim_iomap_table(pci_dev)[2];
 307
 308         pci_set_master(pci_dev);
 309
 310         rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
 311         if (rc)
 312                 goto err_dma_mask;
 313
 314         /* Set up intx irq */
 315         writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
 316         pci_intx(pci_dev, 1);
 317         rc = devm_request_irq(&pci_dev->dev, pci_dev->irq, amd_mp2_irq_isr,
 318                               IRQF_SHARED, dev_name(&pci_dev->dev), privdata);
 319         if (rc)
 320                 pci_err(pci_dev, "Failure requesting irq %i: %d\n",
 321                         pci_dev->irq, rc);
 322
 323         return rc;
 324
 325 err_dma_mask:
 326         pci_clear_master(pci_dev);
 327 err_pci_enable:
 328         pci_set_drvdata(pci_dev, NULL);
 329         return rc;
 330 }
 331
 332 static int amd_mp2_pci_probe(struct pci_dev *pci_dev,
 333                              const struct pci_device_id *id)
 334 {
 335         struct amd_mp2_dev *privdata;
 336         int rc;
 337
 338         privdata = devm_kzalloc(&pci_dev->dev, sizeof(*privdata), GFP_KERNEL);
 339         if (!privdata)
 340                 return -ENOMEM;
 341
 342         privdata->pci_dev = pci_dev;
 343         rc = amd_mp2_pci_init(privdata, pci_dev);
 344         if (rc)
 345                 return rc;
 346
 347         mutex_init(&privdata->c2p_lock);
 348
 349         pm_runtime_set_autosuspend_delay(&pci_dev->dev, 1000);
 350         pm_runtime_use_autosuspend(&pci_dev->dev);
 351         pm_runtime_put_autosuspend(&pci_dev->dev);
 352         pm_runtime_allow(&pci_dev->dev);
 353
 354         privdata->probed = true;
 355
 356         pci_info(pci_dev, "MP2 device registered.\n");
 357         return 0;
 358 }
 359
 360 static void amd_mp2_pci_remove(struct pci_dev *pci_dev)
 361 {
 362         struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
 363
 364         pm_runtime_forbid(&pci_dev->dev);
 365         pm_runtime_get_noresume(&pci_dev->dev);
 366
 367         pci_intx(pci_dev, 0);
 368         pci_clear_master(pci_dev);
 369
 370         amd_mp2_clear_reg(privdata);
 371 }
 372
 373 #ifdef CONFIG_PM
 374 static int amd_mp2_pci_suspend(struct device *dev)
 375 {
 376         struct pci_dev *pci_dev = to_pci_dev(dev);
 377         struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
 378         struct amd_i2c_common *i2c_common;
 379         unsigned int bus_id;
 380         int ret = 0;
 381
 382         for (bus_id = 0; bus_id < 2; bus_id++) {
 383                 i2c_common = privdata->busses[bus_id];
 384                 if (i2c_common)
 385                         i2c_common->suspend(i2c_common);
 386         }
 387
 388         ret = pci_save_state(pci_dev);
 389         if (ret) {
 390                 pci_err(pci_dev, "pci_save_state failed = %d\n", ret);
 391                 return ret;
 392         }
 393
 394         pci_disable_device(pci_dev);
 395         return ret;
 396 }
 397
 398 static int amd_mp2_pci_resume(struct device *dev)
 399 {
 400         struct pci_dev *pci_dev = to_pci_dev(dev);
 401         struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
 402         struct amd_i2c_common *i2c_common;
 403         unsigned int bus_id;
 404         int ret = 0;
 405
 406         pci_restore_state(pci_dev);
 407         ret = pci_enable_device(pci_dev);
 408         if (ret < 0) {
 409                 pci_err(pci_dev, "pci_enable_device failed = %d\n", ret);
 410                 return ret;
 411         }
 412
 413         for (bus_id = 0; bus_id < 2; bus_id++) {
 414                 i2c_common = privdata->busses[bus_id];
 415                 if (i2c_common) {
 416                         ret = i2c_common->resume(i2c_common);
 417                         if (ret < 0)
 418                                 return ret;
 419                 }
 420         }
 421
 422         return ret;
 423 }
 424
 425 static UNIVERSAL_DEV_PM_OPS(amd_mp2_pci_pm_ops, amd_mp2_pci_suspend,
 426                             amd_mp2_pci_resume, NULL);
 427 #endif /* CONFIG_PM */
 428
 429 static const struct pci_device_id amd_mp2_pci_tbl[] = {
 430         {PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_MP2)},
 431         {0}
 432 };
 433 MODULE_DEVICE_TABLE(pci, amd_mp2_pci_tbl);
 434
 435 static struct pci_driver amd_mp2_pci_driver = {
 436         .name           = "i2c_amd_mp2",
 437         .id_table       = amd_mp2_pci_tbl,
 438         .probe          = amd_mp2_pci_probe,
 439         .remove         = amd_mp2_pci_remove,
 440 #ifdef CONFIG_PM
 441         .driver = {
 442                 .pm     = &amd_mp2_pci_pm_ops,
 443         },
 444 #endif
 445 };
 446 module_pci_driver(amd_mp2_pci_driver);
 447
 448 struct amd_mp2_dev *amd_mp2_find_device(void)
 449 {
 450         struct device *dev;
 451         struct pci_dev *pci_dev;
 452
 453         dev = driver_find_next_device(&amd_mp2_pci_driver.driver, NULL);
 454         if (!dev)
 455                 return NULL;
 456
 457         pci_dev = to_pci_dev(dev);
 458         return (struct amd_mp2_dev *)pci_get_drvdata(pci_dev);
 459 }
 460 EXPORT_SYMBOL_GPL(amd_mp2_find_device);
 461
 462 MODULE_DESCRIPTION("AMD(R) PCI-E MP2 I2C Controller Driver");
 463 MODULE_AUTHOR("Shyam Sundar S K <Shyam-sundar.S-k@amd.com>");
 464 MODULE_AUTHOR("Elie Morisse <syniurge@gmail.com>");
 465 MODULE_LICENSE("Dual BSD/GPL");