drivers/mmc/mmc_block.c

   1 /*
   2  * Block driver for media (i.e., flash cards)
   3  *
   4  * Copyright 2002 Hewlett-Packard Company
   5  *
   6  * Use consistent with the GNU GPL is permitted,
   7  * provided that this copyright notice is
   8  * preserved in its entirety in all copies and derived works.
   9  *
  10  * HEWLETT-PACKARD COMPANY MAKES NO WARRANTIES, EXPRESSED OR IMPLIED,
  11  * AS TO THE USEFULNESS OR CORRECTNESS OF THIS CODE OR ITS
  12  * FITNESS FOR ANY PARTICULAR PURPOSE.
  13  *
  14  * Many thanks to Alessandro Rubini and Jonathan Corbet!
  15  *
  16  * Author:  Andrew Christian
  17  *          28 May 2002
  18  */
  19 #include <linux/moduleparam.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22
  23 #include <linux/sched.h>
  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/devfs_fs_kernel.h>
  31 #include <linux/mutex.h>
  32
  33 #include <linux/mmc/card.h>
  34 #include <linux/mmc/protocol.h>
  35
  36 #include <asm/system.h>
  37 #include <asm/uaccess.h>
  38
  39 #include "mmc_queue.h"
  40
  41 /*
  42  * max 8 partitions per card
  43  */
  44 #define MMC_SHIFT       3
  45
  46 static int major;
  47
  48 /*
  49  * There is one mmc_blk_data per slot.
  50  */
  51 struct mmc_blk_data {
  52         spinlock_t      lock;
  53         struct gendisk  *disk;
  54         struct mmc_queue queue;
  55
  56         unsigned int    usage;
  57         unsigned int    block_bits;
  58         unsigned int    read_only;
  59 };
  60
  61 static DEFINE_MUTEX(open_lock);
  62
  63 static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)
  64 {
  65         struct mmc_blk_data *md;
  66
  67         mutex_lock(&open_lock);
  68         md = disk->private_data;
  69         if (md && md->usage == 0)
  70                 md = NULL;
  71         if (md)
  72                 md->usage++;
  73         mutex_unlock(&open_lock);
  74
  75         return md;
  76 }
  77
  78 static void mmc_blk_put(struct mmc_blk_data *md)
  79 {
  80         mutex_lock(&open_lock);
  81         md->usage--;
  82         if (md->usage == 0) {
  83                 put_disk(md->disk);
  84                 mmc_cleanup_queue(&md->queue);
  85                 kfree(md);
  86         }
  87         mutex_unlock(&open_lock);
  88 }
  89
  90 static int mmc_blk_open(struct inode *inode, struct file *filp)
  91 {
  92         struct mmc_blk_data *md;
  93         int ret = -ENXIO;
  94
  95         md = mmc_blk_get(inode->i_bdev->bd_disk);
  96         if (md) {
  97                 if (md->usage == 2)
  98                         check_disk_change(inode->i_bdev);
  99                 ret = 0;
 100
 101                 if ((filp->f_mode & FMODE_WRITE) && md->read_only)
 102                         ret = -EROFS;
 103         }
 104
 105         return ret;
 106 }
 107
 108 static int mmc_blk_release(struct inode *inode, struct file *filp)
 109 {
 110         struct mmc_blk_data *md = inode->i_bdev->bd_disk->private_data;
 111
 112         mmc_blk_put(md);
 113         return 0;
 114 }
 115
 116 static int
 117 mmc_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 118 {
 119         geo->cylinders = get_capacity(bdev->bd_disk) / (4 * 16);
 120         geo->heads = 4;
 121         geo->sectors = 16;
 122         return 0;
 123 }
 124
 125 static struct block_device_operations mmc_bdops = {
 126         .open                   = mmc_blk_open,
 127         .release                = mmc_blk_release,
 128         .getgeo                 = mmc_blk_getgeo,
 129         .owner                  = THIS_MODULE,
 130 };
 131
 132 struct mmc_blk_request {
 133         struct mmc_request      mrq;
 134         struct mmc_command      cmd;
 135         struct mmc_command      stop;
 136         struct mmc_data         data;
 137 };
 138
 139 static int mmc_blk_prep_rq(struct mmc_queue *mq, struct request *req)
 140 {
 141         struct mmc_blk_data *md = mq->data;
 142         int stat = BLKPREP_OK;
 143
 144         /*
 145          * If we have no device, we haven't finished initialising.
 146          */
 147         if (!md || !mq->card) {
 148                 printk(KERN_ERR "%s: killing request - no device/host\n",
 149                        req->rq_disk->disk_name);
 150                 stat = BLKPREP_KILL;
 151         }
 152
 153         return stat;
 154 }
 155
 156 static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
 157 {
 158         struct mmc_blk_data *md = mq->data;
 159         struct mmc_card *card = md->queue.card;
 160         int ret;
 161
 162         if (mmc_card_claim_host(card))
 163                 goto cmd_err;
 164
 165         do {
 166                 struct mmc_blk_request brq;
 167                 struct mmc_command cmd;
 168
 169                 memset(&brq, 0, sizeof(struct mmc_blk_request));
 170                 brq.mrq.cmd = &brq.cmd;
 171                 brq.mrq.data = &brq.data;
 172
 173                 brq.cmd.arg = req->sector << 9;
 174                 brq.cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
 175                 brq.data.timeout_ns = card->csd.tacc_ns * 10;
 176                 brq.data.timeout_clks = card->csd.tacc_clks * 10;
 177                 brq.data.blksz_bits = md->block_bits;
 178                 brq.data.blocks = req->nr_sectors >> (md->block_bits - 9);
 179                 brq.stop.opcode = MMC_STOP_TRANSMISSION;
 180                 brq.stop.arg = 0;
 181                 brq.stop.flags = MMC_RSP_R1B | MMC_CMD_AC;
 182
 183                 if (rq_data_dir(req) == READ) {
 184                         brq.cmd.opcode = brq.data.blocks > 1 ? MMC_READ_MULTIPLE_BLOCK : MMC_READ_SINGLE_BLOCK;
 185                         brq.data.flags |= MMC_DATA_READ;
 186                 } else {
 187                         brq.cmd.opcode = MMC_WRITE_BLOCK;
 188                         brq.data.flags |= MMC_DATA_WRITE;
 189                         brq.data.blocks = 1;
 190                 }
 191
 192                 if (brq.data.blocks > 1) {
 193                         brq.data.flags |= MMC_DATA_MULTI;
 194                         brq.mrq.stop = &brq.stop;
 195                 } else {
 196                         brq.mrq.stop = NULL;
 197                 }
 198
 199                 brq.data.sg = mq->sg;
 200                 brq.data.sg_len = blk_rq_map_sg(req->q, req, brq.data.sg);
 201
 202                 mmc_wait_for_req(card->host, &brq.mrq);
 203                 if (brq.cmd.error) {
 204                         printk(KERN_ERR "%s: error %d sending read/write command\n",
 205                                req->rq_disk->disk_name, brq.cmd.error);
 206                         goto cmd_err;
 207                 }
 208
 209                 if (brq.data.error) {
 210                         printk(KERN_ERR "%s: error %d transferring data\n",
 211                                req->rq_disk->disk_name, brq.data.error);
 212                         goto cmd_err;
 213                 }
 214
 215                 if (brq.stop.error) {
 216                         printk(KERN_ERR "%s: error %d sending stop command\n",
 217                                req->rq_disk->disk_name, brq.stop.error);
 218                         goto cmd_err;
 219                 }
 220
 221                 do {
 222                         int err;
 223
 224                         cmd.opcode = MMC_SEND_STATUS;
 225                         cmd.arg = card->rca << 16;
 226                         cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
 227                         err = mmc_wait_for_cmd(card->host, &cmd, 5);
 228                         if (err) {
 229                                 printk(KERN_ERR "%s: error %d requesting status\n",
 230                                        req->rq_disk->disk_name, err);
 231                                 goto cmd_err;
 232                         }
 233                 } while (!(cmd.resp[0] & R1_READY_FOR_DATA));
 234
 235 #if 0
 236                 if (cmd.resp[0] & ~0x00000900)
 237                         printk(KERN_ERR "%s: status = %08x\n",
 238                                req->rq_disk->disk_name, cmd.resp[0]);
 239                 if (mmc_decode_status(cmd.resp))
 240                         goto cmd_err;
 241 #endif
 242
 243                 /*
 244                  * A block was successfully transferred.
 245                  */
 246                 spin_lock_irq(&md->lock);
 247                 ret = end_that_request_chunk(req, 1, brq.data.bytes_xfered);
 248                 if (!ret) {
 249                         /*
 250                          * The whole request completed successfully.
 251                          */
 252                         add_disk_randomness(req->rq_disk);
 253                         blkdev_dequeue_request(req);
 254                         end_that_request_last(req, 1);
 255                 }
 256                 spin_unlock_irq(&md->lock);
 257         } while (ret);
 258
 259         mmc_card_release_host(card);
 260
 261         return 1;
 262
 263  cmd_err:
 264         mmc_card_release_host(card);
 265
 266         /*
 267          * This is a little draconian, but until we get proper
 268          * error handling sorted out here, its the best we can
 269          * do - especially as some hosts have no idea how much
 270          * data was transferred before the error occurred.
 271          */
 272         spin_lock_irq(&md->lock);
 273         do {
 274                 ret = end_that_request_chunk(req, 0,
 275                                 req->current_nr_sectors << 9);
 276         } while (ret);
 277
 278         add_disk_randomness(req->rq_disk);
 279         blkdev_dequeue_request(req);
 280         end_that_request_last(req, 0);
 281         spin_unlock_irq(&md->lock);
 282
 283         return 0;
 284 }
 285
 286 #define MMC_NUM_MINORS  (256 >> MMC_SHIFT)
 287
 288 static unsigned long dev_use[MMC_NUM_MINORS/(8*sizeof(unsigned long))];
 289
 290 static inline int mmc_blk_readonly(struct mmc_card *card)
 291 {
 292         return mmc_card_readonly(card) ||
 293                !(card->csd.cmdclass & CCC_BLOCK_WRITE);
 294 }
 295
 296 static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card)
 297 {
 298         struct mmc_blk_data *md;
 299         int devidx, ret;
 300
 301         devidx = find_first_zero_bit(dev_use, MMC_NUM_MINORS);
 302         if (devidx >= MMC_NUM_MINORS)
 303                 return ERR_PTR(-ENOSPC);
 304         __set_bit(devidx, dev_use);
 305
 306         md = kmalloc(sizeof(struct mmc_blk_data), GFP_KERNEL);
 307         if (!md) {
 308                 ret = -ENOMEM;
 309                 goto out;
 310         }
 311
 312         memset(md, 0, sizeof(struct mmc_blk_data));
 313
 314         /*
 315          * Set the read-only status based on the supported commands
 316          * and the write protect switch.
 317          */
 318         md->read_only = mmc_blk_readonly(card);
 319
 320         /*
 321          * Figure out a workable block size.  MMC cards have:
 322          *  - two block sizes, one for read and one for write.
 323          *  - may support partial reads and/or writes
 324          *    (allows block sizes smaller than specified)
 325          */
 326         md->block_bits = card->csd.read_blkbits;
 327         if (card->csd.write_blkbits != card->csd.read_blkbits) {
 328                 if (card->csd.write_blkbits < card->csd.read_blkbits &&
 329                     card->csd.read_partial) {
 330                         /*
 331                          * write block size is smaller than read block
 332                          * size, but we support partial reads, so choose
 333                          * the smaller write block size.
 334                          */
 335                         md->block_bits = card->csd.write_blkbits;
 336                 } else if (card->csd.write_blkbits > card->csd.read_blkbits &&
 337                            card->csd.write_partial) {
 338                         /*
 339                          * read block size is smaller than write block
 340                          * size, but we support partial writes.  Use read
 341                          * block size.
 342                          */
 343                 } else {
 344                         /*
 345                          * We don't support this configuration for writes.
 346                          */
 347                         printk(KERN_ERR "%s: unable to select block size for "
 348                                 "writing (rb%u wb%u rp%u wp%u)\n",
 349                                 md->disk->disk_name,
 350                                 1 << card->csd.read_blkbits,
 351                                 1 << card->csd.write_blkbits,
 352                                 card->csd.read_partial,
 353                                 card->csd.write_partial);
 354                         md->read_only = 1;
 355                 }
 356         }
 357
 358         /*
 359          * Refuse to allow block sizes smaller than 512 bytes.
 360          */
 361         if (md->block_bits < 9) {
 362                 printk(KERN_ERR "%s: unable to support block size %u\n",
 363                         mmc_card_id(card), 1 << md->block_bits);
 364                 ret = -EINVAL;
 365                 goto err_kfree;
 366         }
 367
 368         md->disk = alloc_disk(1 << MMC_SHIFT);
 369         if (md->disk == NULL) {
 370                 ret = -ENOMEM;
 371                 goto err_kfree;
 372         }
 373
 374         spin_lock_init(&md->lock);
 375         md->usage = 1;
 376
 377         ret = mmc_init_queue(&md->queue, card, &md->lock);
 378         if (ret)
 379                 goto err_putdisk;
 380
 381         md->queue.prep_fn = mmc_blk_prep_rq;
 382         md->queue.issue_fn = mmc_blk_issue_rq;
 383         md->queue.data = md;
 384
 385         md->disk->major = major;
 386         md->disk->first_minor = devidx << MMC_SHIFT;
 387         md->disk->fops = &mmc_bdops;
 388         md->disk->private_data = md;
 389         md->disk->queue = md->queue.queue;
 390         md->disk->driverfs_dev = &card->dev;
 391
 392         /*
 393          * As discussed on lkml, GENHD_FL_REMOVABLE should:
 394          *
 395          * - be set for removable media with permanent block devices
 396          * - be unset for removable block devices with permanent media
 397          *
 398          * Since MMC block devices clearly fall under the second
 399          * case, we do not set GENHD_FL_REMOVABLE.  Userspace
 400          * should use the block device creation/destruction hotplug
 401          * messages to tell when the card is present.
 402          */
 403
 404         sprintf(md->disk->disk_name, "mmcblk%d", devidx);
 405         sprintf(md->disk->devfs_name, "mmc/blk%d", devidx);
 406
 407         blk_queue_hardsect_size(md->queue.queue, 1 << md->block_bits);
 408
 409         /*
 410          * The CSD capacity field is in units of read_blkbits.
 411          * set_capacity takes units of 512 bytes.
 412          */
 413         set_capacity(md->disk, card->csd.capacity << (card->csd.read_blkbits - 9));
 414         return md;
 415
 416  err_putdisk:
 417         put_disk(md->disk);
 418  err_kfree:
 419         kfree(md);
 420  out:
 421         return ERR_PTR(ret);
 422 }
 423
 424 static int
 425 mmc_blk_set_blksize(struct mmc_blk_data *md, struct mmc_card *card)
 426 {
 427         struct mmc_command cmd;
 428         int err;
 429
 430         mmc_card_claim_host(card);
 431         cmd.opcode = MMC_SET_BLOCKLEN;
 432         cmd.arg = 1 << md->block_bits;
 433         cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
 434         err = mmc_wait_for_cmd(card->host, &cmd, 5);
 435         mmc_card_release_host(card);
 436
 437         if (err) {
 438                 printk(KERN_ERR "%s: unable to set block size to %d: %d\n",
 439                         md->disk->disk_name, cmd.arg, err);
 440                 return -EINVAL;
 441         }
 442
 443         return 0;
 444 }
 445
 446 static int mmc_blk_probe(struct mmc_card *card)
 447 {
 448         struct mmc_blk_data *md;
 449         int err;
 450
 451         /*
 452          * Check that the card supports the command class(es) we need.
 453          */
 454         if (!(card->csd.cmdclass & CCC_BLOCK_READ))
 455                 return -ENODEV;
 456
 457         md = mmc_blk_alloc(card);
 458         if (IS_ERR(md))
 459                 return PTR_ERR(md);
 460
 461         err = mmc_blk_set_blksize(md, card);
 462         if (err)
 463                 goto out;
 464
 465         printk(KERN_INFO "%s: %s %s %lluKiB %s\n",
 466                 md->disk->disk_name, mmc_card_id(card), mmc_card_name(card),
 467                 (unsigned long long)(get_capacity(md->disk) >> 1),
 468                 md->read_only ? "(ro)" : "");
 469
 470         mmc_set_drvdata(card, md);
 471         add_disk(md->disk);
 472         return 0;
 473
 474  out:
 475         mmc_blk_put(md);
 476
 477         return err;
 478 }
 479
 480 static void mmc_blk_remove(struct mmc_card *card)
 481 {
 482         struct mmc_blk_data *md = mmc_get_drvdata(card);
 483
 484         if (md) {
 485                 int devidx;
 486
 487                 del_gendisk(md->disk);
 488
 489                 /*
 490                  * I think this is needed.
 491                  */
 492                 md->disk->queue = NULL;
 493
 494                 devidx = md->disk->first_minor >> MMC_SHIFT;
 495                 __clear_bit(devidx, dev_use);
 496
 497                 mmc_blk_put(md);
 498         }
 499         mmc_set_drvdata(card, NULL);
 500 }
 501
 502 #ifdef CONFIG_PM
 503 static int mmc_blk_suspend(struct mmc_card *card, pm_message_t state)
 504 {
 505         struct mmc_blk_data *md = mmc_get_drvdata(card);
 506
 507         if (md) {
 508                 mmc_queue_suspend(&md->queue);
 509         }
 510         return 0;
 511 }
 512
 513 static int mmc_blk_resume(struct mmc_card *card)
 514 {
 515         struct mmc_blk_data *md = mmc_get_drvdata(card);
 516
 517         if (md) {
 518                 mmc_blk_set_blksize(md, card);
 519                 mmc_queue_resume(&md->queue);
 520         }
 521         return 0;
 522 }
 523 #else
 524 #define mmc_blk_suspend NULL
 525 #define mmc_blk_resume  NULL
 526 #endif
 527
 528 static struct mmc_driver mmc_driver = {
 529         .drv            = {
 530                 .name   = "mmcblk",
 531         },
 532         .probe          = mmc_blk_probe,
 533         .remove         = mmc_blk_remove,
 534         .suspend        = mmc_blk_suspend,
 535         .resume         = mmc_blk_resume,
 536 };
 537
 538 static int __init mmc_blk_init(void)
 539 {
 540         int res = -ENOMEM;
 541
 542         res = register_blkdev(major, "mmc");
 543         if (res < 0) {
 544                 printk(KERN_WARNING "Unable to get major %d for MMC media: %d\n",
 545                        major, res);
 546                 goto out;
 547         }
 548         if (major == 0)
 549                 major = res;
 550
 551         devfs_mk_dir("mmc");
 552         return mmc_register_driver(&mmc_driver);
 553
 554  out:
 555         return res;
 556 }
 557
 558 static void __exit mmc_blk_exit(void)
 559 {
 560         mmc_unregister_driver(&mmc_driver);
 561         devfs_remove("mmc");
 562         unregister_blkdev(major, "mmc");
 563 }
 564
 565 module_init(mmc_blk_init);
 566 module_exit(mmc_blk_exit);
 567
 568 MODULE_LICENSE("GPL");
 569 MODULE_DESCRIPTION("Multimedia Card (MMC) block device driver");
 570
 571 module_param(major, int, 0444);
 572 MODULE_PARM_DESC(major, "specify the major device number for MMC block driver");