drivers/fsi/fsi-scom.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * SCOM FSI Client device driver
   4  *
   5  * Copyright (C) IBM Corporation 2016
   6  */
   7
   8 #include <linux/fsi.h>
   9 #include <linux/module.h>
  10 #include <linux/cdev.h>
  11 #include <linux/delay.h>
  12 #include <linux/fs.h>
  13 #include <linux/uaccess.h>
  14 #include <linux/slab.h>
  15 #include <linux/list.h>
  16
  17 #include <uapi/linux/fsi.h>
  18
  19 #define FSI_ENGID_SCOM          0x5
  20
  21 /* SCOM engine register set */
  22 #define SCOM_DATA0_REG          0x00
  23 #define SCOM_DATA1_REG          0x04
  24 #define SCOM_CMD_REG            0x08
  25 #define SCOM_FSI2PIB_RESET_REG  0x18
  26 #define SCOM_STATUS_REG         0x1C /* Read */
  27 #define SCOM_PIB_RESET_REG      0x1C /* Write */
  28
  29 /* Command register */
  30 #define SCOM_WRITE_CMD          0x80000000
  31 #define SCOM_READ_CMD           0x00000000
  32
  33 /* Status register bits */
  34 #define SCOM_STATUS_ERR_SUMMARY         0x80000000
  35 #define SCOM_STATUS_PROTECTION          0x01000000
  36 #define SCOM_STATUS_PARITY              0x04000000
  37 #define SCOM_STATUS_PIB_ABORT           0x00100000
  38 #define SCOM_STATUS_PIB_RESP_MASK       0x00007000
  39 #define SCOM_STATUS_PIB_RESP_SHIFT      12
  40
  41 #define SCOM_STATUS_FSI2PIB_ERROR       (SCOM_STATUS_PROTECTION |       \
  42                                          SCOM_STATUS_PARITY |           \
  43                                          SCOM_STATUS_PIB_ABORT)
  44 #define SCOM_STATUS_ANY_ERR             (SCOM_STATUS_FSI2PIB_ERROR |    \
  45                                          SCOM_STATUS_PIB_RESP_MASK)
  46 /* SCOM address encodings */
  47 #define XSCOM_ADDR_IND_FLAG             BIT_ULL(63)
  48 #define XSCOM_ADDR_INF_FORM1            BIT_ULL(60)
  49
  50 /* SCOM indirect stuff */
  51 #define XSCOM_ADDR_DIRECT_PART          0x7fffffffull
  52 #define XSCOM_ADDR_INDIRECT_PART        0x000fffff00000000ull
  53 #define XSCOM_DATA_IND_READ             BIT_ULL(63)
  54 #define XSCOM_DATA_IND_COMPLETE         BIT_ULL(31)
  55 #define XSCOM_DATA_IND_ERR_MASK         0x70000000ull
  56 #define XSCOM_DATA_IND_ERR_SHIFT        28
  57 #define XSCOM_DATA_IND_DATA             0x0000ffffull
  58 #define XSCOM_DATA_IND_FORM1_DATA       0x000fffffffffffffull
  59 #define XSCOM_ADDR_FORM1_LOW            0x000ffffffffull
  60 #define XSCOM_ADDR_FORM1_HI             0xfff00000000ull
  61 #define XSCOM_ADDR_FORM1_HI_SHIFT       20
  62
  63 /* Retries */
  64 #define SCOM_MAX_RETRIES                100     /* Retries on busy */
  65 #define SCOM_MAX_IND_RETRIES            10      /* Retries indirect not ready */
  66
  67 struct scom_device {
  68         struct list_head link;
  69         struct fsi_device *fsi_dev;
  70         struct device dev;
  71         struct cdev cdev;
  72         struct mutex lock;
  73         bool dead;
  74 };
  75
  76 static int __put_scom(struct scom_device *scom_dev, uint64_t value,
  77                       uint32_t addr, uint32_t *status)
  78 {
  79         __be32 data, raw_status;
  80         int rc;
  81
  82         data = cpu_to_be32((value >> 32) & 0xffffffff);
  83         rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA0_REG, &data,
  84                                 sizeof(uint32_t));
  85         if (rc)
  86                 return rc;
  87
  88         data = cpu_to_be32(value & 0xffffffff);
  89         rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA1_REG, &data,
  90                                 sizeof(uint32_t));
  91         if (rc)
  92                 return rc;
  93
  94         data = cpu_to_be32(SCOM_WRITE_CMD | addr);
  95         rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,
  96                                 sizeof(uint32_t));
  97         if (rc)
  98                 return rc;
  99         rc = fsi_device_read(scom_dev->fsi_dev, SCOM_STATUS_REG, &raw_status,
 100                              sizeof(uint32_t));
 101         if (rc)
 102                 return rc;
 103         *status = be32_to_cpu(raw_status);
 104
 105         return 0;
 106 }
 107
 108 static int __get_scom(struct scom_device *scom_dev, uint64_t *value,
 109                       uint32_t addr, uint32_t *status)
 110 {
 111         __be32 data, raw_status;
 112         int rc;
 113
 114
 115         *value = 0ULL;
 116         data = cpu_to_be32(SCOM_READ_CMD | addr);
 117         rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,
 118                                 sizeof(uint32_t));
 119         if (rc)
 120                 return rc;
 121         rc = fsi_device_read(scom_dev->fsi_dev, SCOM_STATUS_REG, &raw_status,
 122                              sizeof(uint32_t));
 123         if (rc)
 124                 return rc;
 125
 126         /*
 127          * Read the data registers even on error, so we don't have
 128          * to interpret the status register here.
 129          */
 130         rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA0_REG, &data,
 131                                 sizeof(uint32_t));
 132         if (rc)
 133                 return rc;
 134         *value |= (uint64_t)be32_to_cpu(data) << 32;
 135         rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &data,
 136                                 sizeof(uint32_t));
 137         if (rc)
 138                 return rc;
 139         *value |= be32_to_cpu(data);
 140         *status = be32_to_cpu(raw_status);
 141
 142         return rc;
 143 }
 144
 145 static int put_indirect_scom_form0(struct scom_device *scom, uint64_t value,
 146                                    uint64_t addr, uint32_t *status)
 147 {
 148         uint64_t ind_data, ind_addr;
 149         int rc, retries, err = 0;
 150
 151         if (value & ~XSCOM_DATA_IND_DATA)
 152                 return -EINVAL;
 153
 154         ind_addr = addr & XSCOM_ADDR_DIRECT_PART;
 155         ind_data = (addr & XSCOM_ADDR_INDIRECT_PART) | value;
 156         rc = __put_scom(scom, ind_data, ind_addr, status);
 157         if (rc || (*status & SCOM_STATUS_ANY_ERR))
 158                 return rc;
 159
 160         for (retries = 0; retries < SCOM_MAX_IND_RETRIES; retries++) {
 161                 rc = __get_scom(scom, &ind_data, addr, status);
 162                 if (rc || (*status & SCOM_STATUS_ANY_ERR))
 163                         return rc;
 164
 165                 err = (ind_data & XSCOM_DATA_IND_ERR_MASK) >> XSCOM_DATA_IND_ERR_SHIFT;
 166                 *status = err << SCOM_STATUS_PIB_RESP_SHIFT;
 167                 if ((ind_data & XSCOM_DATA_IND_COMPLETE) || (err != SCOM_PIB_BLOCKED))
 168                         return 0;
 169
 170                 msleep(1);
 171         }
 172         return rc;
 173 }
 174
 175 static int put_indirect_scom_form1(struct scom_device *scom, uint64_t value,
 176                                    uint64_t addr, uint32_t *status)
 177 {
 178         uint64_t ind_data, ind_addr;
 179
 180         if (value & ~XSCOM_DATA_IND_FORM1_DATA)
 181                 return -EINVAL;
 182
 183         ind_addr = addr & XSCOM_ADDR_FORM1_LOW;
 184         ind_data = value | (addr & XSCOM_ADDR_FORM1_HI) << XSCOM_ADDR_FORM1_HI_SHIFT;
 185         return __put_scom(scom, ind_data, ind_addr, status);
 186 }
 187
 188 static int get_indirect_scom_form0(struct scom_device *scom, uint64_t *value,
 189                                    uint64_t addr, uint32_t *status)
 190 {
 191         uint64_t ind_data, ind_addr;
 192         int rc, retries, err = 0;
 193
 194         ind_addr = addr & XSCOM_ADDR_DIRECT_PART;
 195         ind_data = (addr & XSCOM_ADDR_INDIRECT_PART) | XSCOM_DATA_IND_READ;
 196         rc = __put_scom(scom, ind_data, ind_addr, status);
 197         if (rc || (*status & SCOM_STATUS_ANY_ERR))
 198                 return rc;
 199
 200         for (retries = 0; retries < SCOM_MAX_IND_RETRIES; retries++) {
 201                 rc = __get_scom(scom, &ind_data, addr, status);
 202                 if (rc || (*status & SCOM_STATUS_ANY_ERR))
 203                         return rc;
 204
 205                 err = (ind_data & XSCOM_DATA_IND_ERR_MASK) >> XSCOM_DATA_IND_ERR_SHIFT;
 206                 *status = err << SCOM_STATUS_PIB_RESP_SHIFT;
 207                 *value = ind_data & XSCOM_DATA_IND_DATA;
 208
 209                 if ((ind_data & XSCOM_DATA_IND_COMPLETE) || (err != SCOM_PIB_BLOCKED))
 210                         return 0;
 211
 212                 msleep(1);
 213         }
 214         return rc;
 215 }
 216
 217 static int raw_put_scom(struct scom_device *scom, uint64_t value,
 218                         uint64_t addr, uint32_t *status)
 219 {
 220         if (addr & XSCOM_ADDR_IND_FLAG) {
 221                 if (addr & XSCOM_ADDR_INF_FORM1)
 222                         return put_indirect_scom_form1(scom, value, addr, status);
 223                 else
 224                         return put_indirect_scom_form0(scom, value, addr, status);
 225         } else
 226                 return __put_scom(scom, value, addr, status);
 227 }
 228
 229 static int raw_get_scom(struct scom_device *scom, uint64_t *value,
 230                         uint64_t addr, uint32_t *status)
 231 {
 232         if (addr & XSCOM_ADDR_IND_FLAG) {
 233                 if (addr & XSCOM_ADDR_INF_FORM1)
 234                         return -ENXIO;
 235                 return get_indirect_scom_form0(scom, value, addr, status);
 236         } else
 237                 return __get_scom(scom, value, addr, status);
 238 }
 239
 240 static int handle_fsi2pib_status(struct scom_device *scom, uint32_t status)
 241 {
 242         uint32_t dummy = -1;
 243
 244         if (status & SCOM_STATUS_FSI2PIB_ERROR)
 245                 fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy,
 246                                  sizeof(uint32_t));
 247
 248         if (status & SCOM_STATUS_PROTECTION)
 249                 return -EPERM;
 250         if (status & SCOM_STATUS_PARITY)
 251                 return -EIO;
 252         /* Return -EBUSY on PIB abort to force a retry */
 253         if (status & SCOM_STATUS_PIB_ABORT)
 254                 return -EBUSY;
 255         return 0;
 256 }
 257
 258 static int handle_pib_status(struct scom_device *scom, uint8_t status)
 259 {
 260         uint32_t dummy = -1;
 261
 262         if (status == SCOM_PIB_SUCCESS)
 263                 return 0;
 264         if (status == SCOM_PIB_BLOCKED)
 265                 return -EBUSY;
 266
 267         /* Reset the bridge */
 268         fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy,
 269                          sizeof(uint32_t));
 270
 271         switch(status) {
 272         case SCOM_PIB_OFFLINE:
 273                 return -ENODEV;
 274         case SCOM_PIB_BAD_ADDR:
 275                 return -ENXIO;
 276         case SCOM_PIB_TIMEOUT:
 277                 return -ETIMEDOUT;
 278         case SCOM_PIB_PARTIAL:
 279         case SCOM_PIB_CLK_ERR:
 280         case SCOM_PIB_PARITY_ERR:
 281         default:
 282                 return -EIO;
 283         }
 284 }
 285
 286 static int put_scom(struct scom_device *scom, uint64_t value,
 287                     uint64_t addr)
 288 {
 289         uint32_t status, dummy = -1;
 290         int rc, retries;
 291
 292         for (retries = 0; retries < SCOM_MAX_RETRIES; retries++) {
 293                 rc = raw_put_scom(scom, value, addr, &status);
 294                 if (rc) {
 295                         /* Try resetting the bridge if FSI fails */
 296                         if (rc != -ENODEV && retries == 0) {
 297                                 fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG,
 298                                                  &dummy, sizeof(uint32_t));
 299                                 rc = -EBUSY;
 300                         } else
 301                                 return rc;
 302                 } else
 303                         rc = handle_fsi2pib_status(scom, status);
 304                 if (rc && rc != -EBUSY)
 305                         break;
 306                 if (rc == 0) {
 307                         rc = handle_pib_status(scom,
 308                                                (status & SCOM_STATUS_PIB_RESP_MASK)
 309                                                >> SCOM_STATUS_PIB_RESP_SHIFT);
 310                         if (rc && rc != -EBUSY)
 311                                 break;
 312                 }
 313                 if (rc == 0)
 314                         break;
 315                 msleep(1);
 316         }
 317         return rc;
 318 }
 319
 320 static int get_scom(struct scom_device *scom, uint64_t *value,
 321                     uint64_t addr)
 322 {
 323         uint32_t status, dummy = -1;
 324         int rc, retries;
 325
 326         for (retries = 0; retries < SCOM_MAX_RETRIES; retries++) {
 327                 rc = raw_get_scom(scom, value, addr, &status);
 328                 if (rc) {
 329                         /* Try resetting the bridge if FSI fails */
 330                         if (rc != -ENODEV && retries == 0) {
 331                                 fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG,
 332                                                  &dummy, sizeof(uint32_t));
 333                                 rc = -EBUSY;
 334                         } else
 335                                 return rc;
 336                 } else
 337                         rc = handle_fsi2pib_status(scom, status);
 338                 if (rc && rc != -EBUSY)
 339                         break;
 340                 if (rc == 0) {
 341                         rc = handle_pib_status(scom,
 342                                                (status & SCOM_STATUS_PIB_RESP_MASK)
 343                                                >> SCOM_STATUS_PIB_RESP_SHIFT);
 344                         if (rc && rc != -EBUSY)
 345                                 break;
 346                 }
 347                 if (rc == 0)
 348                         break;
 349                 msleep(1);
 350         }
 351         return rc;
 352 }
 353
 354 static ssize_t scom_read(struct file *filep, char __user *buf, size_t len,
 355                          loff_t *offset)
 356 {
 357         struct scom_device *scom = filep->private_data;
 358         struct device *dev = &scom->fsi_dev->dev;
 359         uint64_t val;
 360         int rc;
 361
 362         if (len != sizeof(uint64_t))
 363                 return -EINVAL;
 364
 365         mutex_lock(&scom->lock);
 366         if (scom->dead)
 367                 rc = -ENODEV;
 368         else
 369                 rc = get_scom(scom, &val, *offset);
 370         mutex_unlock(&scom->lock);
 371         if (rc) {
 372                 dev_dbg(dev, "get_scom fail:%d\n", rc);
 373                 return rc;
 374         }
 375
 376         rc = copy_to_user(buf, &val, len);
 377         if (rc)
 378                 dev_dbg(dev, "copy to user failed:%d\n", rc);
 379
 380         return rc ? rc : len;
 381 }
 382
 383 static ssize_t scom_write(struct file *filep, const char __user *buf,
 384                           size_t len, loff_t *offset)
 385 {
 386         int rc;
 387         struct scom_device *scom = filep->private_data;
 388         struct device *dev = &scom->fsi_dev->dev;
 389         uint64_t val;
 390
 391         if (len != sizeof(uint64_t))
 392                 return -EINVAL;
 393
 394         rc = copy_from_user(&val, buf, len);
 395         if (rc) {
 396                 dev_dbg(dev, "copy from user failed:%d\n", rc);
 397                 return -EINVAL;
 398         }
 399
 400         mutex_lock(&scom->lock);
 401         if (scom->dead)
 402                 rc = -ENODEV;
 403         else
 404                 rc = put_scom(scom, val, *offset);
 405         mutex_unlock(&scom->lock);
 406         if (rc) {
 407                 dev_dbg(dev, "put_scom failed with:%d\n", rc);
 408                 return rc;
 409         }
 410
 411         return len;
 412 }
 413
 414 static loff_t scom_llseek(struct file *file, loff_t offset, int whence)
 415 {
 416         switch (whence) {
 417         case SEEK_CUR:
 418                 break;
 419         case SEEK_SET:
 420                 file->f_pos = offset;
 421                 break;
 422         default:
 423                 return -EINVAL;
 424         }
 425
 426         return offset;
 427 }
 428
 429 static void raw_convert_status(struct scom_access *acc, uint32_t status)
 430 {
 431         acc->pib_status = (status & SCOM_STATUS_PIB_RESP_MASK) >>
 432                 SCOM_STATUS_PIB_RESP_SHIFT;
 433         acc->intf_errors = 0;
 434
 435         if (status & SCOM_STATUS_PROTECTION)
 436                 acc->intf_errors |= SCOM_INTF_ERR_PROTECTION;
 437         else if (status & SCOM_STATUS_PARITY)
 438                 acc->intf_errors |= SCOM_INTF_ERR_PARITY;
 439         else if (status & SCOM_STATUS_PIB_ABORT)
 440                 acc->intf_errors |= SCOM_INTF_ERR_ABORT;
 441         else if (status & SCOM_STATUS_ERR_SUMMARY)
 442                 acc->intf_errors |= SCOM_INTF_ERR_UNKNOWN;
 443 }
 444
 445 static int scom_raw_read(struct scom_device *scom, void __user *argp)
 446 {
 447         struct scom_access acc;
 448         uint32_t status;
 449         int rc;
 450
 451         if (copy_from_user(&acc, argp, sizeof(struct scom_access)))
 452                 return -EFAULT;
 453
 454         rc = raw_get_scom(scom, &acc.data, acc.addr, &status);
 455         if (rc)
 456                 return rc;
 457         raw_convert_status(&acc, status);
 458         if (copy_to_user(argp, &acc, sizeof(struct scom_access)))
 459                 return -EFAULT;
 460         return 0;
 461 }
 462
 463 static int scom_raw_write(struct scom_device *scom, void __user *argp)
 464 {
 465         u64 prev_data, mask, data;
 466         struct scom_access acc;
 467         uint32_t status;
 468         int rc;
 469
 470         if (copy_from_user(&acc, argp, sizeof(struct scom_access)))
 471                 return -EFAULT;
 472
 473         if (acc.mask) {
 474                 rc = raw_get_scom(scom, &prev_data, acc.addr, &status);
 475                 if (rc)
 476                         return rc;
 477                 if (status & SCOM_STATUS_ANY_ERR)
 478                         goto fail;
 479                 mask = acc.mask;
 480         } else {
 481                 prev_data = mask = -1ull;
 482         }
 483         data = (prev_data & ~mask) | (acc.data & mask);
 484         rc = raw_put_scom(scom, data, acc.addr, &status);
 485         if (rc)
 486                 return rc;
 487  fail:
 488         raw_convert_status(&acc, status);
 489         if (copy_to_user(argp, &acc, sizeof(struct scom_access)))
 490                 return -EFAULT;
 491         return 0;
 492 }
 493
 494 static int scom_reset(struct scom_device *scom, void __user *argp)
 495 {
 496         uint32_t flags, dummy = -1;
 497         int rc = 0;
 498
 499         if (get_user(flags, (__u32 __user *)argp))
 500                 return -EFAULT;
 501         if (flags & SCOM_RESET_PIB)
 502                 rc = fsi_device_write(scom->fsi_dev, SCOM_PIB_RESET_REG, &dummy,
 503                                       sizeof(uint32_t));
 504         if (!rc && (flags & (SCOM_RESET_PIB | SCOM_RESET_INTF)))
 505                 rc = fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy,
 506                                       sizeof(uint32_t));
 507         return rc;
 508 }
 509
 510 static int scom_check(struct scom_device *scom, void __user *argp)
 511 {
 512         /* Still need to find out how to get "protected" */
 513         return put_user(SCOM_CHECK_SUPPORTED, (__u32 __user *)argp);
 514 }
 515
 516 static long scom_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 517 {
 518         struct scom_device *scom = file->private_data;
 519         void __user *argp = (void __user *)arg;
 520         int rc = -ENOTTY;
 521
 522         mutex_lock(&scom->lock);
 523         if (scom->dead) {
 524                 mutex_unlock(&scom->lock);
 525                 return -ENODEV;
 526         }
 527         switch(cmd) {
 528         case FSI_SCOM_CHECK:
 529                 rc = scom_check(scom, argp);
 530                 break;
 531         case FSI_SCOM_READ:
 532                 rc = scom_raw_read(scom, argp);
 533                 break;
 534         case FSI_SCOM_WRITE:
 535                 rc = scom_raw_write(scom, argp);
 536                 break;
 537         case FSI_SCOM_RESET:
 538                 rc = scom_reset(scom, argp);
 539                 break;
 540         }
 541         mutex_unlock(&scom->lock);
 542         return rc;
 543 }
 544
 545 static int scom_open(struct inode *inode, struct file *file)
 546 {
 547         struct scom_device *scom = container_of(inode->i_cdev, struct scom_device, cdev);
 548
 549         file->private_data = scom;
 550
 551         return 0;
 552 }
 553
 554 static const struct file_operations scom_fops = {
 555         .owner          = THIS_MODULE,
 556         .open           = scom_open,
 557         .llseek         = scom_llseek,
 558         .read           = scom_read,
 559         .write          = scom_write,
 560         .unlocked_ioctl = scom_ioctl,
 561 };
 562
 563 static void scom_free(struct device *dev)
 564 {
 565         struct scom_device *scom = container_of(dev, struct scom_device, dev);
 566
 567         put_device(&scom->fsi_dev->dev);
 568         kfree(scom);
 569 }
 570
 571 static int scom_probe(struct device *dev)
 572 {
 573         struct fsi_device *fsi_dev = to_fsi_dev(dev);
 574         struct scom_device *scom;
 575         int rc, didx;
 576
 577         scom = kzalloc(sizeof(*scom), GFP_KERNEL);
 578         if (!scom)
 579                 return -ENOMEM;
 580         dev_set_drvdata(dev, scom);
 581         mutex_init(&scom->lock);
 582
 583         /* Grab a reference to the device (parent of our cdev), we'll drop it later */
 584         if (!get_device(dev)) {
 585                 kfree(scom);
 586                 return -ENODEV;
 587         }
 588         scom->fsi_dev = fsi_dev;
 589
 590         /* Create chardev for userspace access */
 591         scom->dev.type = &fsi_cdev_type;
 592         scom->dev.parent = dev;
 593         scom->dev.release = scom_free;
 594         device_initialize(&scom->dev);
 595
 596         /* Allocate a minor in the FSI space */
 597         rc = fsi_get_new_minor(fsi_dev, fsi_dev_scom, &scom->dev.devt, &didx);
 598         if (rc)
 599                 goto err;
 600
 601         dev_set_name(&scom->dev, "scom%d", didx);
 602         cdev_init(&scom->cdev, &scom_fops);
 603         rc = cdev_device_add(&scom->cdev, &scom->dev);
 604         if (rc) {
 605                 dev_err(dev, "Error %d creating char device %s\n",
 606                         rc, dev_name(&scom->dev));
 607                 goto err_free_minor;
 608         }
 609
 610         return 0;
 611  err_free_minor:
 612         fsi_free_minor(scom->dev.devt);
 613  err:
 614         put_device(&scom->dev);
 615         return rc;
 616 }
 617
 618 static int scom_remove(struct device *dev)
 619 {
 620         struct scom_device *scom = dev_get_drvdata(dev);
 621
 622         mutex_lock(&scom->lock);
 623         scom->dead = true;
 624         mutex_unlock(&scom->lock);
 625         cdev_device_del(&scom->cdev, &scom->dev);
 626         fsi_free_minor(scom->dev.devt);
 627         put_device(&scom->dev);
 628
 629         return 0;
 630 }
 631
 632 static const struct fsi_device_id scom_ids[] = {
 633         {
 634                 .engine_type = FSI_ENGID_SCOM,
 635                 .version = FSI_VERSION_ANY,
 636         },
 637         { 0 }
 638 };
 639
 640 static struct fsi_driver scom_drv = {
 641         .id_table = scom_ids,
 642         .drv = {
 643                 .name = "scom",
 644                 .bus = &fsi_bus_type,
 645                 .probe = scom_probe,
 646                 .remove = scom_remove,
 647         }
 648 };
 649
 650 static int scom_init(void)
 651 {
 652         return fsi_driver_register(&scom_drv);
 653 }
 654
 655 static void scom_exit(void)
 656 {
 657         fsi_driver_unregister(&scom_drv);
 658 }
 659
 660 module_init(scom_init);
 661 module_exit(scom_exit);
 662 MODULE_LICENSE("GPL");