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