drivers/mmc/card/block.c

   1 /*
   2  * Block driver for media (i.e., flash cards)
   3  *
   4  * Copyright 2002 Hewlett-Packard Company
   5  * Copyright 2005-2008 Pierre Ossman
   6  *
   7  * Use consistent with the GNU GPL is permitted,
   8  * provided that this copyright notice is
   9  * preserved in its entirety in all copies and derived works.
  10  *
  11  * HEWLETT-PACKARD COMPANY MAKES NO WARRANTIES, EXPRESSED OR IMPLIED,
  12  * AS TO THE USEFULNESS OR CORRECTNESS OF THIS CODE OR ITS
  13  * FITNESS FOR ANY PARTICULAR PURPOSE.
  14  *
  15  * Many thanks to Alessandro Rubini and Jonathan Corbet!
  16  *
  17  * Author:  Andrew Christian
  18  *          28 May 2002
  19  */
  20 #include <linux/moduleparam.h>
  21 #include <linux/module.h>
  22 #include <linux/init.h>
  23
  24 #include <linux/kernel.h>
  25 #include <linux/fs.h>
  26 #include <linux/errno.h>
  27 #include <linux/hdreg.h>
  28 #include <linux/kdev_t.h>
  29 #include <linux/blkdev.h>
  30 #include <linux/mutex.h>
  31 #include <linux/scatterlist.h>
  32 #include <linux/string_helpers.h>
  33
  34 #include <linux/mmc/card.h>
  35 #include <linux/mmc/host.h>
  36 #include <linux/mmc/mmc.h>
  37 #include <linux/mmc/sd.h>
  38
  39 #include <asm/system.h>
  40 #include <asm/uaccess.h>
  41
  42 #include "queue.h"
  43
  44 MODULE_ALIAS("mmc:block");
  45
  46 /*
  47  * max 8 partitions per card
  48  */
  49 #define MMC_SHIFT       3
  50 #define MMC_NUM_MINORS  (256 >> MMC_SHIFT)
  51
  52 static DECLARE_BITMAP(dev_use, MMC_NUM_MINORS);
  53
  54 /*
  55  * There is one mmc_blk_data per slot.
  56  */
  57 struct mmc_blk_data {
  58         spinlock_t      lock;
  59         struct gendisk  *disk;
  60         struct mmc_queue queue;
  61
  62         unsigned int    usage;
  63         unsigned int    read_only;
  64 };
  65
  66 static DEFINE_MUTEX(open_lock);
  67
  68 static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)
  69 {
  70         struct mmc_blk_data *md;
  71
  72         mutex_lock(&open_lock);
  73         md = disk->private_data;
  74         if (md && md->usage == 0)
  75                 md = NULL;
  76         if (md)
  77                 md->usage++;
  78         mutex_unlock(&open_lock);
  79
  80         return md;
  81 }
  82
  83 static void mmc_blk_put(struct mmc_blk_data *md)
  84 {
  85         mutex_lock(&open_lock);
  86         md->usage--;
  87         if (md->usage == 0) {
  88                 int devmaj = MAJOR(disk_devt(md->disk));
  89                 int devidx = MINOR(disk_devt(md->disk)) >> MMC_SHIFT;
  90
  91                 if (!devmaj)
  92                         devidx = md->disk->first_minor >> MMC_SHIFT;
  93
  94                 blk_cleanup_queue(md->queue.queue);
  95
  96                 __clear_bit(devidx, dev_use);
  97
  98                 put_disk(md->disk);
  99                 kfree(md);
 100         }
 101         mutex_unlock(&open_lock);
 102 }
 103
 104 static int mmc_blk_open(struct block_device *bdev, fmode_t mode)
 105 {
 106         struct mmc_blk_data *md = mmc_blk_get(bdev->bd_disk);
 107         int ret = -ENXIO;
 108
 109         if (md) {
 110                 if (md->usage == 2)
 111                         check_disk_change(bdev);
 112                 ret = 0;
 113
 114                 if ((mode & FMODE_WRITE) && md->read_only) {
 115                         mmc_blk_put(md);
 116                         ret = -EROFS;
 117                 }
 118         }
 119
 120         return ret;
 121 }
 122
 123 static int mmc_blk_release(struct gendisk *disk, fmode_t mode)
 124 {
 125         struct mmc_blk_data *md = disk->private_data;
 126
 127         mmc_blk_put(md);
 128         return 0;
 129 }
 130
 131 static int
 132 mmc_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 133 {
 134         geo->cylinders = get_capacity(bdev->bd_disk) / (4 * 16);
 135         geo->heads = 4;
 136         geo->sectors = 16;
 137         return 0;
 138 }
 139
 140 static const struct block_device_operations mmc_bdops = {
 141         .open                   = mmc_blk_open,
 142         .release                = mmc_blk_release,
 143         .getgeo                 = mmc_blk_getgeo,
 144         .owner                  = THIS_MODULE,
 145 };
 146
 147 struct mmc_blk_request {
 148         struct mmc_request      mrq;
 149         struct mmc_command      cmd;
 150         struct mmc_command      stop;
 151         struct mmc_data         data;
 152 };
 153
 154 static u32 mmc_sd_num_wr_blocks(struct mmc_card *card)
 155 {
 156         int err;
 157         u32 result;
 158         __be32 *blocks;
 159
 160         struct mmc_request mrq;
 161         struct mmc_command cmd;
 162         struct mmc_data data;
 163         unsigned int timeout_us;
 164
 165         struct scatterlist sg;
 166
 167         memset(&cmd, 0, sizeof(struct mmc_command));
 168
 169         cmd.opcode = MMC_APP_CMD;
 170         cmd.arg = card->rca << 16;
 171         cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
 172
 173         err = mmc_wait_for_cmd(card->host, &cmd, 0);
 174         if (err)
 175                 return (u32)-1;
 176         if (!mmc_host_is_spi(card->host) && !(cmd.resp[0] & R1_APP_CMD))
 177                 return (u32)-1;
 178
 179         memset(&cmd, 0, sizeof(struct mmc_command));
 180
 181         cmd.opcode = SD_APP_SEND_NUM_WR_BLKS;
 182         cmd.arg = 0;
 183         cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
 184
 185         memset(&data, 0, sizeof(struct mmc_data));
 186
 187         data.timeout_ns = card->csd.tacc_ns * 100;
 188         data.timeout_clks = card->csd.tacc_clks * 100;
 189
 190         timeout_us = data.timeout_ns / 1000;
 191         timeout_us += data.timeout_clks * 1000 /
 192                 (card->host->ios.clock / 1000);
 193
 194         if (timeout_us > 100000) {
 195                 data.timeout_ns = 100000000;
 196                 data.timeout_clks = 0;
 197         }
 198
 199         data.blksz = 4;
 200         data.blocks = 1;
 201         data.flags = MMC_DATA_READ;
 202         data.sg = &sg;
 203         data.sg_len = 1;
 204
 205         memset(&mrq, 0, sizeof(struct mmc_request));
 206
 207         mrq.cmd = &cmd;
 208         mrq.data = &data;
 209
 210         blocks = kmalloc(4, GFP_KERNEL);
 211         if (!blocks)
 212                 return (u32)-1;
 213
 214         sg_init_one(&sg, blocks, 4);
 215
 216         mmc_wait_for_req(card->host, &mrq);
 217
 218         result = ntohl(*blocks);
 219         kfree(blocks);
 220
 221         if (cmd.error || data.error)
 222                 result = (u32)-1;
 223
 224         return result;
 225 }
 226
 227 static u32 get_card_status(struct mmc_card *card, struct request *req)
 228 {
 229         struct mmc_command cmd;
 230         int err;
 231
 232         memset(&cmd, 0, sizeof(struct mmc_command));
 233         cmd.opcode = MMC_SEND_STATUS;
 234         if (!mmc_host_is_spi(card->host))
 235                 cmd.arg = card->rca << 16;
 236         cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_AC;
 237         err = mmc_wait_for_cmd(card->host, &cmd, 0);
 238         if (err)
 239                 printk(KERN_ERR "%s: error %d sending status comand",
 240                        req->rq_disk->disk_name, err);
 241         return cmd.resp[0];
 242 }
 243
 244 static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 245 {
 246         struct mmc_blk_data *md = mq->data;
 247         struct mmc_card *card = md->queue.card;
 248         struct mmc_blk_request brq;
 249         int ret = 1, disable_multi = 0;
 250
 251         mmc_claim_host(card->host);
 252
 253         do {
 254                 struct mmc_command cmd;
 255                 u32 readcmd, writecmd, status = 0;
 256
 257                 memset(&brq, 0, sizeof(struct mmc_blk_request));
 258                 brq.mrq.cmd = &brq.cmd;
 259                 brq.mrq.data = &brq.data;
 260
 261                 brq.cmd.arg = blk_rq_pos(req);
 262                 if (!mmc_card_blockaddr(card))
 263                         brq.cmd.arg <<= 9;
 264                 brq.cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
 265                 brq.data.blksz = 512;
 266                 brq.stop.opcode = MMC_STOP_TRANSMISSION;
 267                 brq.stop.arg = 0;
 268                 brq.stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
 269                 brq.data.blocks = blk_rq_sectors(req);
 270
 271                 /*
 272                  * The block layer doesn't support all sector count
 273                  * restrictions, so we need to be prepared for too big
 274                  * requests.
 275                  */
 276                 if (brq.data.blocks > card->host->max_blk_count)
 277                         brq.data.blocks = card->host->max_blk_count;
 278
 279                 /*
 280                  * After a read error, we redo the request one sector at a time
 281                  * in order to accurately determine which sectors can be read
 282                  * successfully.
 283                  */
 284                 if (disable_multi && brq.data.blocks > 1)
 285                         brq.data.blocks = 1;
 286
 287                 if (brq.data.blocks > 1) {
 288                         /* SPI multiblock writes terminate using a special
 289                          * token, not a STOP_TRANSMISSION request.
 290                          */
 291                         if (!mmc_host_is_spi(card->host)
 292                                         || rq_data_dir(req) == READ)
 293                                 brq.mrq.stop = &brq.stop;
 294                         readcmd = MMC_READ_MULTIPLE_BLOCK;
 295                         writecmd = MMC_WRITE_MULTIPLE_BLOCK;
 296                 } else {
 297                         brq.mrq.stop = NULL;
 298                         readcmd = MMC_READ_SINGLE_BLOCK;
 299                         writecmd = MMC_WRITE_BLOCK;
 300                 }
 301
 302                 if (rq_data_dir(req) == READ) {
 303                         brq.cmd.opcode = readcmd;
 304                         brq.data.flags |= MMC_DATA_READ;
 305                 } else {
 306                         brq.cmd.opcode = writecmd;
 307                         brq.data.flags |= MMC_DATA_WRITE;
 308                 }
 309
 310                 mmc_set_data_timeout(&brq.data, card);
 311
 312                 brq.data.sg = mq->sg;
 313                 brq.data.sg_len = mmc_queue_map_sg(mq);
 314
 315                 /*
 316                  * Adjust the sg list so it is the same size as the
 317                  * request.
 318                  */
 319                 if (brq.data.blocks != blk_rq_sectors(req)) {
 320                         int i, data_size = brq.data.blocks << 9;
 321                         struct scatterlist *sg;
 322
 323                         for_each_sg(brq.data.sg, sg, brq.data.sg_len, i) {
 324                                 data_size -= sg->length;
 325                                 if (data_size <= 0) {
 326                                         sg->length += data_size;
 327                                         i++;
 328                                         break;
 329                                 }
 330                         }
 331                         brq.data.sg_len = i;
 332                 }
 333
 334                 mmc_queue_bounce_pre(mq);
 335
 336                 mmc_wait_for_req(card->host, &brq.mrq);
 337
 338                 mmc_queue_bounce_post(mq);
 339
 340                 /*
 341                  * Check for errors here, but don't jump to cmd_err
 342                  * until later as we need to wait for the card to leave
 343                  * programming mode even when things go wrong.
 344                  */
 345                 if (brq.cmd.error || brq.data.error || brq.stop.error) {
 346                         if (brq.data.blocks > 1 && rq_data_dir(req) == READ) {
 347                                 /* Redo read one sector at a time */
 348                                 printk(KERN_WARNING "%s: retrying using single "
 349                                        "block read\n", req->rq_disk->disk_name);
 350                                 disable_multi = 1;
 351                                 continue;
 352                         }
 353                         status = get_card_status(card, req);
 354                 }
 355
 356                 if (brq.cmd.error) {
 357                         printk(KERN_ERR "%s: error %d sending read/write "
 358                                "command, response %#x, card status %#x\n",
 359                                req->rq_disk->disk_name, brq.cmd.error,
 360                                brq.cmd.resp[0], status);
 361                 }
 362
 363                 if (brq.data.error) {
 364                         if (brq.data.error == -ETIMEDOUT && brq.mrq.stop)
 365                                 /* 'Stop' response contains card status */
 366                                 status = brq.mrq.stop->resp[0];
 367                         printk(KERN_ERR "%s: error %d transferring data,"
 368                                " sector %u, nr %u, card status %#x\n",
 369                                req->rq_disk->disk_name, brq.data.error,
 370                                (unsigned)blk_rq_pos(req),
 371                                (unsigned)blk_rq_sectors(req), status);
 372                 }
 373
 374                 if (brq.stop.error) {
 375                         printk(KERN_ERR "%s: error %d sending stop command, "
 376                                "response %#x, card status %#x\n",
 377                                req->rq_disk->disk_name, brq.stop.error,
 378                                brq.stop.resp[0], status);
 379                 }
 380
 381                 if (!mmc_host_is_spi(card->host) && rq_data_dir(req) != READ) {
 382                         do {
 383                                 int err;
 384
 385                                 cmd.opcode = MMC_SEND_STATUS;
 386                                 cmd.arg = card->rca << 16;
 387                                 cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
 388                                 err = mmc_wait_for_cmd(card->host, &cmd, 5);
 389                                 if (err) {
 390                                         printk(KERN_ERR "%s: error %d requesting status\n",
 391                                                req->rq_disk->disk_name, err);
 392                                         goto cmd_err;
 393                                 }
 394                                 /*
 395                                  * Some cards mishandle the status bits,
 396                                  * so make sure to check both the busy
 397                                  * indication and the card state.
 398                                  */
 399                         } while (!(cmd.resp[0] & R1_READY_FOR_DATA) ||
 400                                 (R1_CURRENT_STATE(cmd.resp[0]) == 7));
 401
 402 #if 0
 403                         if (cmd.resp[0] & ~0x00000900)
 404                                 printk(KERN_ERR "%s: status = %08x\n",
 405                                        req->rq_disk->disk_name, cmd.resp[0]);
 406                         if (mmc_decode_status(cmd.resp))
 407                                 goto cmd_err;
 408 #endif
 409                 }
 410
 411                 if (brq.cmd.error || brq.stop.error || brq.data.error) {
 412                         if (rq_data_dir(req) == READ) {
 413                                 /*
 414                                  * After an error, we redo I/O one sector at a
 415                                  * time, so we only reach here after trying to
 416                                  * read a single sector.
 417                                  */
 418                                 spin_lock_irq(&md->lock);
 419                                 ret = __blk_end_request(req, -EIO, brq.data.blksz);
 420                                 spin_unlock_irq(&md->lock);
 421                                 continue;
 422                         }
 423                         goto cmd_err;
 424                 }
 425
 426                 /*
 427                  * A block was successfully transferred.
 428                  */
 429                 spin_lock_irq(&md->lock);
 430                 ret = __blk_end_request(req, 0, brq.data.bytes_xfered);
 431                 spin_unlock_irq(&md->lock);
 432         } while (ret);
 433
 434         mmc_release_host(card->host);
 435
 436         return 1;
 437
 438  cmd_err:
 439         /*
 440          * If this is an SD card and we're writing, we can first
 441          * mark the known good sectors as ok.
 442          *
 443          * If the card is not SD, we can still ok written sectors
 444          * as reported by the controller (which might be less than
 445          * the real number of written sectors, but never more).
 446          */
 447         if (mmc_card_sd(card)) {
 448                 u32 blocks;
 449
 450                 blocks = mmc_sd_num_wr_blocks(card);
 451                 if (blocks != (u32)-1) {
 452                         spin_lock_irq(&md->lock);
 453                         ret = __blk_end_request(req, 0, blocks << 9);
 454                         spin_unlock_irq(&md->lock);
 455                 }
 456         } else {
 457                 spin_lock_irq(&md->lock);
 458                 ret = __blk_end_request(req, 0, brq.data.bytes_xfered);
 459                 spin_unlock_irq(&md->lock);
 460         }
 461
 462         mmc_release_host(card->host);
 463
 464         spin_lock_irq(&md->lock);
 465         while (ret)
 466                 ret = __blk_end_request(req, -EIO, blk_rq_cur_bytes(req));
 467         spin_unlock_irq(&md->lock);
 468
 469         return 0;
 470 }
 471
 472
 473 static inline int mmc_blk_readonly(struct mmc_card *card)
 474 {
 475         return mmc_card_readonly(card) ||
 476                !(card->csd.cmdclass & CCC_BLOCK_WRITE);
 477 }
 478
 479 static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
 480 {
 481         struct mmc_blk_data *md;
 482         int devidx, ret;
 483
 484         devidx = find_first_zero_bit(dev_use, MMC_NUM_MINORS);
 485         if (devidx >= MMC_NUM_MINORS)
 486                 return ERR_PTR(-ENOSPC);
 487         __set_bit(devidx, dev_use);
 488
 489         md = kzalloc(sizeof(struct mmc_blk_data), GFP_KERNEL);
 490         if (!md) {
 491                 ret = -ENOMEM;
 492                 goto out;
 493         }
 494
 495
 496         /*
 497          * Set the read-only status based on the supported commands
 498          * and the write protect switch.
 499          */
 500         md->read_only = mmc_blk_readonly(card);
 501
 502         md->disk = alloc_disk(1 << MMC_SHIFT);
 503         if (md->disk == NULL) {
 504                 ret = -ENOMEM;
 505                 goto err_kfree;
 506         }
 507
 508         spin_lock_init(&md->lock);
 509         md->usage = 1;
 510
 511         ret = mmc_init_queue(&md->queue, card, &md->lock);
 512         if (ret)
 513                 goto err_putdisk;
 514
 515         md->queue.issue_fn = mmc_blk_issue_rq;
 516         md->queue.data = md;
 517
 518         md->disk->major = MMC_BLOCK_MAJOR;
 519         md->disk->first_minor = devidx << MMC_SHIFT;
 520         md->disk->fops = &mmc_bdops;
 521         md->disk->private_data = md;
 522         md->disk->queue = md->queue.queue;
 523         md->disk->driverfs_dev = &card->dev;
 524
 525         /*
 526          * As discussed on lkml, GENHD_FL_REMOVABLE should:
 527          *
 528          * - be set for removable media with permanent block devices
 529          * - be unset for removable block devices with permanent media
 530          *
 531          * Since MMC block devices clearly fall under the second
 532          * case, we do not set GENHD_FL_REMOVABLE.  Userspace
 533          * should use the block device creation/destruction hotplug
 534          * messages to tell when the card is present.
 535          */
 536
 537         sprintf(md->disk->disk_name, "mmcblk%d", devidx);
 538
 539         blk_queue_logical_block_size(md->queue.queue, 512);
 540
 541         if (!mmc_card_sd(card) && mmc_card_blockaddr(card)) {
 542                 /*
 543                  * The EXT_CSD sector count is in number or 512 byte
 544                  * sectors.
 545                  */
 546                 set_capacity(md->disk, card->ext_csd.sectors);
 547         } else {
 548                 /*
 549                  * The CSD capacity field is in units of read_blkbits.
 550                  * set_capacity takes units of 512 bytes.
 551                  */
 552                 set_capacity(md->disk,
 553                         card->csd.capacity << (card->csd.read_blkbits - 9));
 554         }
 555         return md;
 556
 557  err_putdisk:
 558         put_disk(md->disk);
 559  err_kfree:
 560         kfree(md);
 561  out:
 562         return ERR_PTR(ret);
 563 }
 564
 565 static int
 566 mmc_blk_set_blksize(struct mmc_blk_data *md, struct mmc_card *card)
 567 {
 568         struct mmc_command cmd;
 569         int err;
 570
 571         /* Block-addressed cards ignore MMC_SET_BLOCKLEN. */
 572         if (mmc_card_blockaddr(card))
 573                 return 0;
 574
 575         mmc_claim_host(card->host);
 576         cmd.opcode = MMC_SET_BLOCKLEN;
 577         cmd.arg = 512;
 578         cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
 579         err = mmc_wait_for_cmd(card->host, &cmd, 5);
 580         mmc_release_host(card->host);
 581
 582         if (err) {
 583                 printk(KERN_ERR "%s: unable to set block size to %d: %d\n",
 584                         md->disk->disk_name, cmd.arg, err);
 585                 return -EINVAL;
 586         }
 587
 588         return 0;
 589 }
 590
 591 static int mmc_blk_probe(struct mmc_card *card)
 592 {
 593         struct mmc_blk_data *md;
 594         int err;
 595
 596         char cap_str[10];
 597
 598         /*
 599          * Check that the card supports the command class(es) we need.
 600          */
 601         if (!(card->csd.cmdclass & CCC_BLOCK_READ))
 602                 return -ENODEV;
 603
 604         md = mmc_blk_alloc(card);
 605         if (IS_ERR(md))
 606                 return PTR_ERR(md);
 607
 608         err = mmc_blk_set_blksize(md, card);
 609         if (err)
 610                 goto out;
 611
 612         string_get_size((u64)get_capacity(md->disk) << 9, STRING_UNITS_2,
 613                         cap_str, sizeof(cap_str));
 614         printk(KERN_INFO "%s: %s %s %s %s\n",
 615                 md->disk->disk_name, mmc_card_id(card), mmc_card_name(card),
 616                 cap_str, md->read_only ? "(ro)" : "");
 617
 618         mmc_set_drvdata(card, md);
 619         add_disk(md->disk);
 620         return 0;
 621
 622  out:
 623         mmc_cleanup_queue(&md->queue);
 624         mmc_blk_put(md);
 625
 626         return err;
 627 }
 628
 629 static void mmc_blk_remove(struct mmc_card *card)
 630 {
 631         struct mmc_blk_data *md = mmc_get_drvdata(card);
 632
 633         if (md) {
 634                 /* Stop new requests from getting into the queue */
 635                 del_gendisk(md->disk);
 636
 637                 /* Then flush out any already in there */
 638                 mmc_cleanup_queue(&md->queue);
 639
 640                 mmc_blk_put(md);
 641         }
 642         mmc_set_drvdata(card, NULL);
 643 }
 644
 645 #ifdef CONFIG_PM
 646 static int mmc_blk_suspend(struct mmc_card *card, pm_message_t state)
 647 {
 648         struct mmc_blk_data *md = mmc_get_drvdata(card);
 649
 650         if (md) {
 651                 mmc_queue_suspend(&md->queue);
 652         }
 653         return 0;
 654 }
 655
 656 static int mmc_blk_resume(struct mmc_card *card)
 657 {
 658         struct mmc_blk_data *md = mmc_get_drvdata(card);
 659
 660         if (md) {
 661                 mmc_blk_set_blksize(md, card);
 662                 mmc_queue_resume(&md->queue);
 663         }
 664         return 0;
 665 }
 666 #else
 667 #define mmc_blk_suspend NULL
 668 #define mmc_blk_resume  NULL
 669 #endif
 670
 671 static struct mmc_driver mmc_driver = {
 672         .drv            = {
 673                 .name   = "mmcblk",
 674         },
 675         .probe          = mmc_blk_probe,
 676         .remove         = mmc_blk_remove,
 677         .suspend        = mmc_blk_suspend,
 678         .resume         = mmc_blk_resume,
 679 };
 680
 681 static int __init mmc_blk_init(void)
 682 {
 683         int res;
 684
 685         res = register_blkdev(MMC_BLOCK_MAJOR, "mmc");
 686         if (res)
 687                 goto out;
 688
 689         res = mmc_register_driver(&mmc_driver);
 690         if (res)
 691                 goto out2;
 692
 693         return 0;
 694  out2:
 695         unregister_blkdev(MMC_BLOCK_MAJOR, "mmc");
 696  out:
 697         return res;
 698 }
 699
 700 static void __exit mmc_blk_exit(void)
 701 {
 702         mmc_unregister_driver(&mmc_driver);
 703         unregister_blkdev(MMC_BLOCK_MAJOR, "mmc");
 704 }
 705
 706 module_init(mmc_blk_init);
 707 module_exit(mmc_blk_exit);
 708
 709 MODULE_LICENSE("GPL");
 710 MODULE_DESCRIPTION("Multimedia Card (MMC) block device driver");
 711