drivers/fsi/fsi-scom.c

   1 /*
   2  * SCOM FSI Client device driver
   3  *
   4  * Copyright (C) IBM Corporation 2016
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERGCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/fsi.h>
  17 #include <linux/module.h>
  18 #include <linux/cdev.h>
  19 #include <linux/delay.h>
  20 #include <linux/fs.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/slab.h>
  23 #include <linux/cdev.h>
  24 #include <linux/list.h>
  25
  26 #include <uapi/linux/fsi.h>
  27
  28 #define FSI_ENGID_SCOM          0x5
  29
  30 /* SCOM engine register set */
  31 #define SCOM_DATA0_REG          0x00
  32 #define SCOM_DATA1_REG          0x04
  33 #define SCOM_CMD_REG            0x08
  34 #define SCOM_FSI2PIB_RESET_REG  0x18
  35 #define SCOM_STATUS_REG         0x1C /* Read */
  36 #define SCOM_PIB_RESET_REG      0x1C /* Write */
  37
  38 /* Command register */
  39 #define SCOM_WRITE_CMD          0x80000000
  40 #define SCOM_READ_CMD           0x00000000
  41
  42 /* Status register bits */
  43 #define SCOM_STATUS_ERR_SUMMARY         0x80000000
  44 #define SCOM_STATUS_PROTECTION          0x01000000
  45 #define SCOM_STATUS_PARITY              0x04000000
  46 #define SCOM_STATUS_PIB_ABORT           0x00100000
  47 #define SCOM_STATUS_PIB_RESP_MASK       0x00007000
  48 #define SCOM_STATUS_PIB_RESP_SHIFT      12
  49
  50 #define SCOM_STATUS_ANY_ERR             (SCOM_STATUS_ERR_SUMMARY | \
  51                                          SCOM_STATUS_PROTECTION | \
  52                                          SCOM_STATUS_PARITY |     \
  53                                          SCOM_STATUS_PIB_ABORT | \
  54                                          SCOM_STATUS_PIB_RESP_MASK)
  55 /* SCOM address encodings */
  56 #define XSCOM_ADDR_IND_FLAG             BIT_ULL(63)
  57 #define XSCOM_ADDR_INF_FORM1            BIT_ULL(60)
  58
  59 /* SCOM indirect stuff */
  60 #define XSCOM_ADDR_DIRECT_PART          0x7fffffffull
  61 #define XSCOM_ADDR_INDIRECT_PART        0x000fffff00000000ull
  62 #define XSCOM_DATA_IND_READ             BIT_ULL(63)
  63 #define XSCOM_DATA_IND_COMPLETE         BIT_ULL(31)
  64 #define XSCOM_DATA_IND_ERR_MASK         0x70000000ull
  65 #define XSCOM_DATA_IND_ERR_SHIFT        28
  66 #define XSCOM_DATA_IND_DATA             0x0000ffffull
  67 #define XSCOM_DATA_IND_FORM1_DATA       0x000fffffffffffffull
  68 #define XSCOM_ADDR_FORM1_LOW            0x000ffffffffull
  69 #define XSCOM_ADDR_FORM1_HI             0xfff00000000ull
  70 #define XSCOM_ADDR_FORM1_HI_SHIFT       20
  71
  72 /* Retries */
  73 #define SCOM_MAX_RETRIES                100     /* Retries on busy */
  74 #define SCOM_MAX_IND_RETRIES            10      /* Retries indirect not ready */
  75
  76 struct scom_device {
  77         struct list_head link;
  78         struct fsi_device *fsi_dev;
  79         struct device dev;
  80         struct cdev cdev;
  81         struct mutex lock;
  82         bool dead;
  83 };
  84
  85 static int __put_scom(struct scom_device *scom_dev, uint64_t value,
  86                       uint32_t addr, uint32_t *status)
  87 {
  88         __be32 data, raw_status;
  89         int rc;
  90
  91         data = cpu_to_be32((value >> 32) & 0xffffffff);
  92         rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA0_REG, &data,
  93                                 sizeof(uint32_t));
  94         if (rc)
  95                 return rc;
  96
  97         data = cpu_to_be32(value & 0xffffffff);
  98         rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA1_REG, &data,
  99                                 sizeof(uint32_t));
 100         if (rc)
 101                 return rc;
 102
 103         data = cpu_to_be32(SCOM_WRITE_CMD | addr);
 104         rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,
 105                                 sizeof(uint32_t));
 106         if (rc)
 107                 return rc;
 108         rc = fsi_device_read(scom_dev->fsi_dev, SCOM_STATUS_REG, &raw_status,
 109                              sizeof(uint32_t));
 110         if (rc)
 111                 return rc;
 112         *status = be32_to_cpu(raw_status);
 113
 114         return 0;
 115 }
 116
 117 static int __get_scom(struct scom_device *scom_dev, uint64_t *value,
 118                       uint32_t addr, uint32_t *status)
 119 {
 120         __be32 data, raw_status;
 121         int rc;
 122
 123
 124         *value = 0ULL;
 125         data = cpu_to_be32(SCOM_READ_CMD | addr);
 126         rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,
 127                                 sizeof(uint32_t));
 128         if (rc)
 129                 return rc;
 130         rc = fsi_device_read(scom_dev->fsi_dev, SCOM_STATUS_REG, &raw_status,
 131                              sizeof(uint32_t));
 132         if (rc)
 133                 return rc;
 134
 135         /*
 136          * Read the data registers even on error, so we don't have
 137          * to interpret the status register here.
 138          */
 139         rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA0_REG, &data,
 140                                 sizeof(uint32_t));
 141         if (rc)
 142                 return rc;
 143         *value |= (uint64_t)be32_to_cpu(data) << 32;
 144         rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &data,
 145                                 sizeof(uint32_t));
 146         if (rc)
 147                 return rc;
 148         *value |= be32_to_cpu(data);
 149         *status = be32_to_cpu(raw_status);
 150
 151         return rc;
 152 }
 153
 154 static int put_indirect_scom_form0(struct scom_device *scom, uint64_t value,
 155                                    uint64_t addr, uint32_t *status)
 156 {
 157         uint64_t ind_data, ind_addr;
 158         int rc, retries, err = 0;
 159
 160         if (value & ~XSCOM_DATA_IND_DATA)
 161                 return -EINVAL;
 162
 163         ind_addr = addr & XSCOM_ADDR_DIRECT_PART;
 164         ind_data = (addr & XSCOM_ADDR_INDIRECT_PART) | value;
 165         rc = __put_scom(scom, ind_data, ind_addr, status);
 166         if (rc || (*status & SCOM_STATUS_ANY_ERR))
 167                 return rc;
 168
 169         for (retries = 0; retries < SCOM_MAX_IND_RETRIES; retries++) {
 170                 rc = __get_scom(scom, &ind_data, addr, status);
 171                 if (rc || (*status & SCOM_STATUS_ANY_ERR))
 172                         return rc;
 173
 174                 err = (ind_data & XSCOM_DATA_IND_ERR_MASK) >> XSCOM_DATA_IND_ERR_SHIFT;
 175                 *status = err << SCOM_STATUS_PIB_RESP_SHIFT;
 176                 if ((ind_data & XSCOM_DATA_IND_COMPLETE) || (err != SCOM_PIB_BLOCKED))
 177                         return 0;
 178
 179                 msleep(1);
 180         }
 181         return rc;
 182 }
 183
 184 static int put_indirect_scom_form1(struct scom_device *scom, uint64_t value,
 185                                    uint64_t addr, uint32_t *status)
 186 {
 187         uint64_t ind_data, ind_addr;
 188
 189         if (value & ~XSCOM_DATA_IND_FORM1_DATA)
 190                 return -EINVAL;
 191
 192         ind_addr = addr & XSCOM_ADDR_FORM1_LOW;
 193         ind_data = value | (addr & XSCOM_ADDR_FORM1_HI) << XSCOM_ADDR_FORM1_HI_SHIFT;
 194         return __put_scom(scom, ind_data, ind_addr, status);
 195 }
 196
 197 static int get_indirect_scom_form0(struct scom_device *scom, uint64_t *value,
 198                                    uint64_t addr, uint32_t *status)
 199 {
 200         uint64_t ind_data, ind_addr;
 201         int rc, retries, err = 0;
 202
 203         ind_addr = addr & XSCOM_ADDR_DIRECT_PART;
 204         ind_data = (addr & XSCOM_ADDR_INDIRECT_PART) | XSCOM_DATA_IND_READ;
 205         rc = __put_scom(scom, ind_data, ind_addr, status);
 206         if (rc || (*status & SCOM_STATUS_ANY_ERR))
 207                 return rc;
 208
 209         for (retries = 0; retries < SCOM_MAX_IND_RETRIES; retries++) {
 210                 rc = __get_scom(scom, &ind_data, addr, status);
 211                 if (rc || (*status & SCOM_STATUS_ANY_ERR))
 212                         return rc;
 213
 214                 err = (ind_data & XSCOM_DATA_IND_ERR_MASK) >> XSCOM_DATA_IND_ERR_SHIFT;
 215                 *status = err << SCOM_STATUS_PIB_RESP_SHIFT;
 216                 *value = ind_data & XSCOM_DATA_IND_DATA;
 217
 218                 if ((ind_data & XSCOM_DATA_IND_COMPLETE) || (err != SCOM_PIB_BLOCKED))
 219                         return 0;
 220
 221                 msleep(1);
 222         }
 223         return rc;
 224 }
 225
 226 static int raw_put_scom(struct scom_device *scom, uint64_t value,
 227                         uint64_t addr, uint32_t *status)
 228 {
 229         if (addr & XSCOM_ADDR_IND_FLAG) {
 230                 if (addr & XSCOM_ADDR_INF_FORM1)
 231                         return put_indirect_scom_form1(scom, value, addr, status);
 232                 else
 233                         return put_indirect_scom_form0(scom, value, addr, status);
 234         } else
 235                 return __put_scom(scom, value, addr, status);
 236 }
 237
 238 static int raw_get_scom(struct scom_device *scom, uint64_t *value,
 239                         uint64_t addr, uint32_t *status)
 240 {
 241         if (addr & XSCOM_ADDR_IND_FLAG) {
 242                 if (addr & XSCOM_ADDR_INF_FORM1)
 243                         return -ENXIO;
 244                 return get_indirect_scom_form0(scom, value, addr, status);
 245         } else
 246                 return __get_scom(scom, value, addr, status);
 247 }
 248
 249 static int handle_fsi2pib_status(struct scom_device *scom, uint32_t status)
 250 {
 251         uint32_t dummy = -1;
 252
 253         if (status & SCOM_STATUS_PROTECTION)
 254                 return -EPERM;
 255         if (status & SCOM_STATUS_PARITY) {
 256                 fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy,
 257                                  sizeof(uint32_t));
 258                 return -EIO;
 259         }
 260         /* Return -EBUSY on PIB abort to force a retry */
 261         if (status & SCOM_STATUS_PIB_ABORT)
 262                 return -EBUSY;
 263         if (status & SCOM_STATUS_ERR_SUMMARY) {
 264                 fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy,
 265                                  sizeof(uint32_t));
 266                 return -EIO;
 267         }
 268         return 0;
 269 }
 270
 271 static int handle_pib_status(struct scom_device *scom, uint8_t status)
 272 {
 273         uint32_t dummy = -1;
 274
 275         if (status == SCOM_PIB_SUCCESS)
 276                 return 0;
 277         if (status == SCOM_PIB_BLOCKED)
 278                 return -EBUSY;
 279
 280         /* Reset the bridge */
 281         fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy,
 282                          sizeof(uint32_t));
 283
 284         switch(status) {
 285         case SCOM_PIB_OFFLINE:
 286                 return -ENODEV;
 287         case SCOM_PIB_BAD_ADDR:
 288                 return -ENXIO;
 289         case SCOM_PIB_TIMEOUT:
 290                 return -ETIMEDOUT;
 291         case SCOM_PIB_PARTIAL:
 292         case SCOM_PIB_CLK_ERR:
 293         case SCOM_PIB_PARITY_ERR:
 294         default:
 295                 return -EIO;
 296         }
 297 }
 298
 299 static int put_scom(struct scom_device *scom, uint64_t value,
 300                     uint64_t addr)
 301 {
 302         uint32_t status, dummy = -1;
 303         int rc, retries;
 304
 305         for (retries = 0; retries < SCOM_MAX_RETRIES; retries++) {
 306                 rc = raw_put_scom(scom, value, addr, &status);
 307                 if (rc) {
 308                         /* Try resetting the bridge if FSI fails */
 309                         if (rc != -ENODEV && retries == 0) {
 310                                 fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG,
 311                                                  &dummy, sizeof(uint32_t));
 312                                 rc = -EBUSY;
 313                         } else
 314                                 return rc;
 315                 } else
 316                         rc = handle_fsi2pib_status(scom, status);
 317                 if (rc && rc != -EBUSY)
 318                         break;
 319                 if (rc == 0) {
 320                         rc = handle_pib_status(scom,
 321                                                (status & SCOM_STATUS_PIB_RESP_MASK)
 322                                                >> SCOM_STATUS_PIB_RESP_SHIFT);
 323                         if (rc && rc != -EBUSY)
 324                                 break;
 325                 }
 326                 if (rc == 0)
 327                         break;
 328                 msleep(1);
 329         }
 330         return rc;
 331 }
 332
 333 static int get_scom(struct scom_device *scom, uint64_t *value,
 334                     uint64_t addr)
 335 {
 336         uint32_t status, dummy = -1;
 337         int rc, retries;
 338
 339         for (retries = 0; retries < SCOM_MAX_RETRIES; retries++) {
 340                 rc = raw_get_scom(scom, value, addr, &status);
 341                 if (rc) {
 342                         /* Try resetting the bridge if FSI fails */
 343                         if (rc != -ENODEV && retries == 0) {
 344                                 fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG,
 345                                                  &dummy, sizeof(uint32_t));
 346                                 rc = -EBUSY;
 347                         } else
 348                                 return rc;
 349                 } else
 350                         rc = handle_fsi2pib_status(scom, status);
 351                 if (rc && rc != -EBUSY)
 352                         break;
 353                 if (rc == 0) {
 354                         rc = handle_pib_status(scom,
 355                                                (status & SCOM_STATUS_PIB_RESP_MASK)
 356                                                >> SCOM_STATUS_PIB_RESP_SHIFT);
 357                         if (rc && rc != -EBUSY)
 358                                 break;
 359                 }
 360                 if (rc == 0)
 361                         break;
 362                 msleep(1);
 363         }
 364         return rc;
 365 }
 366
 367 static ssize_t scom_read(struct file *filep, char __user *buf, size_t len,
 368                          loff_t *offset)
 369 {
 370         struct scom_device *scom = filep->private_data;
 371         struct device *dev = &scom->fsi_dev->dev;
 372         uint64_t val;
 373         int rc;
 374
 375         if (len != sizeof(uint64_t))
 376                 return -EINVAL;
 377
 378         mutex_lock(&scom->lock);
 379         if (scom->dead)
 380                 rc = -ENODEV;
 381         else
 382                 rc = get_scom(scom, &val, *offset);
 383         mutex_unlock(&scom->lock);
 384         if (rc) {
 385                 dev_dbg(dev, "get_scom fail:%d\n", rc);
 386                 return rc;
 387         }
 388
 389         rc = copy_to_user(buf, &val, len);
 390         if (rc)
 391                 dev_dbg(dev, "copy to user failed:%d\n", rc);
 392
 393         return rc ? rc : len;
 394 }
 395
 396 static ssize_t scom_write(struct file *filep, const char __user *buf,
 397                           size_t len, loff_t *offset)
 398 {
 399         int rc;
 400         struct scom_device *scom = filep->private_data;
 401         struct device *dev = &scom->fsi_dev->dev;
 402         uint64_t val;
 403
 404         if (len != sizeof(uint64_t))
 405                 return -EINVAL;
 406
 407         rc = copy_from_user(&val, buf, len);
 408         if (rc) {
 409                 dev_dbg(dev, "copy from user failed:%d\n", rc);
 410                 return -EINVAL;
 411         }
 412
 413         mutex_lock(&scom->lock);
 414         if (scom->dead)
 415                 rc = -ENODEV;
 416         else
 417                 rc = put_scom(scom, val, *offset);
 418         mutex_unlock(&scom->lock);
 419         if (rc) {
 420                 dev_dbg(dev, "put_scom failed with:%d\n", rc);
 421                 return rc;
 422         }
 423
 424         return len;
 425 }
 426
 427 static loff_t scom_llseek(struct file *file, loff_t offset, int whence)
 428 {
 429         switch (whence) {
 430         case SEEK_CUR:
 431                 break;
 432         case SEEK_SET:
 433                 file->f_pos = offset;
 434                 break;
 435         default:
 436                 return -EINVAL;
 437         }
 438
 439         return offset;
 440 }
 441
 442 static void raw_convert_status(struct scom_access *acc, uint32_t status)
 443 {
 444         acc->pib_status = (status & SCOM_STATUS_PIB_RESP_MASK) >>
 445                 SCOM_STATUS_PIB_RESP_SHIFT;
 446         acc->intf_errors = 0;
 447
 448         if (status & SCOM_STATUS_PROTECTION)
 449                 acc->intf_errors |= SCOM_INTF_ERR_PROTECTION;
 450         else if (status & SCOM_STATUS_PARITY)
 451                 acc->intf_errors |= SCOM_INTF_ERR_PARITY;
 452         else if (status & SCOM_STATUS_PIB_ABORT)
 453                 acc->intf_errors |= SCOM_INTF_ERR_ABORT;
 454         else if (status & SCOM_STATUS_ERR_SUMMARY)
 455                 acc->intf_errors |= SCOM_INTF_ERR_UNKNOWN;
 456 }
 457
 458 static int scom_raw_read(struct scom_device *scom, void __user *argp)
 459 {
 460         struct scom_access acc;
 461         uint32_t status;
 462         int rc;
 463
 464         if (copy_from_user(&acc, argp, sizeof(struct scom_access)))
 465                 return -EFAULT;
 466
 467         rc = raw_get_scom(scom, &acc.data, acc.addr, &status);
 468         if (rc)
 469                 return rc;
 470         raw_convert_status(&acc, status);
 471         if (copy_to_user(argp, &acc, sizeof(struct scom_access)))
 472                 return -EFAULT;
 473         return 0;
 474 }
 475
 476 static int scom_raw_write(struct scom_device *scom, void __user *argp)
 477 {
 478         u64 prev_data, mask, data;
 479         struct scom_access acc;
 480         uint32_t status;
 481         int rc;
 482
 483         if (copy_from_user(&acc, argp, sizeof(struct scom_access)))
 484                 return -EFAULT;
 485
 486         if (acc.mask) {
 487                 rc = raw_get_scom(scom, &prev_data, acc.addr, &status);
 488                 if (rc)
 489                         return rc;
 490                 if (status & SCOM_STATUS_ANY_ERR)
 491                         goto fail;
 492                 mask = acc.mask;
 493         } else {
 494                 prev_data = mask = -1ull;
 495         }
 496         data = (prev_data & ~mask) | (acc.data & mask);
 497         rc = raw_put_scom(scom, data, acc.addr, &status);
 498         if (rc)
 499                 return rc;
 500  fail:
 501         raw_convert_status(&acc, status);
 502         if (copy_to_user(argp, &acc, sizeof(struct scom_access)))
 503                 return -EFAULT;
 504         return 0;
 505 }
 506
 507 static int scom_reset(struct scom_device *scom, void __user *argp)
 508 {
 509         uint32_t flags, dummy = -1;
 510         int rc = 0;
 511
 512         if (get_user(flags, (__u32 __user *)argp))
 513                 return -EFAULT;
 514         if (flags & SCOM_RESET_PIB)
 515                 rc = fsi_device_write(scom->fsi_dev, SCOM_PIB_RESET_REG, &dummy,
 516                                       sizeof(uint32_t));
 517         if (!rc && (flags & (SCOM_RESET_PIB | SCOM_RESET_INTF)))
 518                 rc = fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy,
 519                                       sizeof(uint32_t));
 520         return rc;
 521 }
 522
 523 static int scom_check(struct scom_device *scom, void __user *argp)
 524 {
 525         /* Still need to find out how to get "protected" */
 526         return put_user(SCOM_CHECK_SUPPORTED, (__u32 __user *)argp);
 527 }
 528
 529 static long scom_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 530 {
 531         struct scom_device *scom = file->private_data;
 532         void __user *argp = (void __user *)arg;
 533         int rc = -ENOTTY;
 534
 535         mutex_lock(&scom->lock);
 536         if (scom->dead) {
 537                 mutex_unlock(&scom->lock);
 538                 return -ENODEV;
 539         }
 540         switch(cmd) {
 541         case FSI_SCOM_CHECK:
 542                 rc = scom_check(scom, argp);
 543                 break;
 544         case FSI_SCOM_READ:
 545                 rc = scom_raw_read(scom, argp);
 546                 break;
 547         case FSI_SCOM_WRITE:
 548                 rc = scom_raw_write(scom, argp);
 549                 break;
 550         case FSI_SCOM_RESET:
 551                 rc = scom_reset(scom, argp);
 552                 break;
 553         }
 554         mutex_unlock(&scom->lock);
 555         return rc;
 556 }
 557
 558 static int scom_open(struct inode *inode, struct file *file)
 559 {
 560         struct scom_device *scom = container_of(inode->i_cdev, struct scom_device, cdev);
 561
 562         file->private_data = scom;
 563
 564         return 0;
 565 }
 566
 567 static const struct file_operations scom_fops = {
 568         .owner          = THIS_MODULE,
 569         .open           = scom_open,
 570         .llseek         = scom_llseek,
 571         .read           = scom_read,
 572         .write          = scom_write,
 573         .unlocked_ioctl = scom_ioctl,
 574 };
 575
 576 static void scom_free(struct device *dev)
 577 {
 578         struct scom_device *scom = container_of(dev, struct scom_device, dev);
 579
 580         put_device(&scom->fsi_dev->dev);
 581         kfree(scom);
 582 }
 583
 584 static int scom_probe(struct device *dev)
 585 {
 586         struct fsi_device *fsi_dev = to_fsi_dev(dev);
 587         struct scom_device *scom;
 588         int rc, didx;
 589
 590         scom = kzalloc(sizeof(*scom), GFP_KERNEL);
 591         if (!scom)
 592                 return -ENOMEM;
 593         dev_set_drvdata(dev, scom);
 594         mutex_init(&scom->lock);
 595
 596         /* Grab a reference to the device (parent of our cdev), we'll drop it later */
 597         if (!get_device(dev)) {
 598                 kfree(scom);
 599                 return -ENODEV;
 600         }
 601         scom->fsi_dev = fsi_dev;
 602
 603         /* Create chardev for userspace access */
 604         scom->dev.type = &fsi_cdev_type;
 605         scom->dev.parent = dev;
 606         scom->dev.release = scom_free;
 607         device_initialize(&scom->dev);
 608
 609         /* Allocate a minor in the FSI space */
 610         rc = fsi_get_new_minor(fsi_dev, fsi_dev_scom, &scom->dev.devt, &didx);
 611         if (rc)
 612                 goto err;
 613
 614         dev_set_name(&scom->dev, "scom%d", didx);
 615         cdev_init(&scom->cdev, &scom_fops);
 616         rc = cdev_device_add(&scom->cdev, &scom->dev);
 617         if (rc) {
 618                 dev_err(dev, "Error %d creating char device %s\n",
 619                         rc, dev_name(&scom->dev));
 620                 goto err_free_minor;
 621         }
 622
 623         return 0;
 624  err_free_minor:
 625         fsi_free_minor(scom->dev.devt);
 626  err:
 627         put_device(&scom->dev);
 628         return rc;
 629 }
 630
 631 static int scom_remove(struct device *dev)
 632 {
 633         struct scom_device *scom = dev_get_drvdata(dev);
 634
 635         mutex_lock(&scom->lock);
 636         scom->dead = true;
 637         mutex_unlock(&scom->lock);
 638         cdev_device_del(&scom->cdev, &scom->dev);
 639         fsi_free_minor(scom->dev.devt);
 640         put_device(&scom->dev);
 641
 642         return 0;
 643 }
 644
 645 static struct fsi_device_id scom_ids[] = {
 646         {
 647                 .engine_type = FSI_ENGID_SCOM,
 648                 .version = FSI_VERSION_ANY,
 649         },
 650         { 0 }
 651 };
 652
 653 static struct fsi_driver scom_drv = {
 654         .id_table = scom_ids,
 655         .drv = {
 656                 .name = "scom",
 657                 .bus = &fsi_bus_type,
 658                 .probe = scom_probe,
 659                 .remove = scom_remove,
 660         }
 661 };
 662
 663 static int scom_init(void)
 664 {
 665         return fsi_driver_register(&scom_drv);
 666 }
 667
 668 static void scom_exit(void)
 669 {
 670         fsi_driver_unregister(&scom_drv);
 671 }
 672
 673 module_init(scom_init);
 674 module_exit(scom_exit);
 675 MODULE_LICENSE("GPL");