drivers/mtd/mtd_blkdevs.c

   1 /*
   2  * Interface to Linux block layer for MTD 'translation layers'.
   3  *
   4  * Copyright © 2003-2010 David Woodhouse <dwmw2@infradead.org>
   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 as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/slab.h>
  24 #include <linux/module.h>
  25 #include <linux/list.h>
  26 #include <linux/fs.h>
  27 #include <linux/mtd/blktrans.h>
  28 #include <linux/mtd/mtd.h>
  29 #include <linux/blkdev.h>
  30 #include <linux/blkpg.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/smp_lock.h>
  33 #include <linux/hdreg.h>
  34 #include <linux/init.h>
  35 #include <linux/mutex.h>
  36 #include <linux/kthread.h>
  37 #include <asm/uaccess.h>
  38
  39 #include "mtdcore.h"
  40
  41 static LIST_HEAD(blktrans_majors);
  42 static DEFINE_MUTEX(blktrans_ref_mutex);
  43
  44 void blktrans_dev_release(struct kref *kref)
  45 {
  46         struct mtd_blktrans_dev *dev =
  47                 container_of(kref, struct mtd_blktrans_dev, ref);
  48
  49         dev->disk->private_data = NULL;
  50         blk_cleanup_queue(dev->rq);
  51         put_disk(dev->disk);
  52         list_del(&dev->list);
  53         kfree(dev);
  54 }
  55
  56 static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
  57 {
  58         struct mtd_blktrans_dev *dev;
  59
  60         mutex_lock(&blktrans_ref_mutex);
  61         dev = disk->private_data;
  62
  63         if (!dev)
  64                 goto unlock;
  65         kref_get(&dev->ref);
  66 unlock:
  67         mutex_unlock(&blktrans_ref_mutex);
  68         return dev;
  69 }
  70
  71 void blktrans_dev_put(struct mtd_blktrans_dev *dev)
  72 {
  73         mutex_lock(&blktrans_ref_mutex);
  74         kref_put(&dev->ref, blktrans_dev_release);
  75         mutex_unlock(&blktrans_ref_mutex);
  76 }
  77
  78
  79 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
  80                                struct mtd_blktrans_dev *dev,
  81                                struct request *req)
  82 {
  83         unsigned long block, nsect;
  84         char *buf;
  85 #if 0
  86         block = blk_rq_pos(req) << 9 >> tr->blkshift;
  87         nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
  88 #else  //modify by zyf for cap>=4GB 20110120
  89         block = blk_rq_pos(req);
  90         nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
  91     if(tr->blkshift != 9)
  92     {
  93         if(tr->blkshift > 9)
  94         {
  95             block = blk_rq_pos(req) >> (tr->blkshift - 9);
  96         }
  97         else
  98         {
  99                 block = blk_rq_pos(req) << (9 - tr->blkshift);
 100         }
 101     }
 102 #endif
 103
 104         buf = req->buffer;
 105
 106         if (req->cmd_type != REQ_TYPE_FS)
 107                 return -EIO;
 108
 109         if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
 110             get_capacity(req->rq_disk))
 111                 return -EIO;
 112
 113         if (req->cmd_flags & REQ_DISCARD)
 114                 return tr->discard(dev, block, nsect);
 115
 116         switch(rq_data_dir(req)) {
 117         case READ:
 118                 //for (; nsect > 0; nsect--, block++, buf += tr->blksize)
 119                         if (tr->readsect(dev, block,nsect, buf))
 120                                 return -EIO;
 121                 rq_flush_dcache_pages(req);
 122                 return 0;
 123         case WRITE:
 124                 if (!tr->writesect)
 125                         return -EIO;
 126
 127                 rq_flush_dcache_pages(req);
 128                 //for (; nsect > 0; nsect--, block++, buf += tr->blksize)
 129                         if (tr->writesect(dev, block,nsect, buf))
 130                                 return -EIO;
 131                 return 0;
 132         default:
 133                 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
 134                 return -EIO;
 135         }
 136 }
 137
 138 static int mtd_blktrans_thread(void *arg)
 139 {
 140         struct mtd_blktrans_dev *dev = arg;
 141         struct request_queue *rq = dev->rq;
 142         struct request *req = NULL;
 143
 144         spin_lock_irq(rq->queue_lock);
 145
 146         while (!kthread_should_stop()) {
 147                 int res;
 148
 149                 if (!req && !(req = blk_fetch_request(rq))) {
 150                         set_current_state(TASK_INTERRUPTIBLE);
 151                         spin_unlock_irq(rq->queue_lock);
 152                         schedule();
 153                         spin_lock_irq(rq->queue_lock);
 154                         continue;
 155                 }
 156
 157                 spin_unlock_irq(rq->queue_lock);
 158
 159                 mutex_lock(&dev->lock);
 160                 res = do_blktrans_request(dev->tr, dev, req);
 161                 mutex_unlock(&dev->lock);
 162
 163                 spin_lock_irq(rq->queue_lock);
 164
 165                 if (!__blk_end_request_cur(req, res))
 166                         req = NULL;
 167         }
 168
 169         if (req)
 170                 __blk_end_request_all(req, -EIO);
 171
 172         spin_unlock_irq(rq->queue_lock);
 173
 174         return 0;
 175 }
 176
 177 static void mtd_blktrans_request(struct request_queue *rq)
 178 {
 179         struct mtd_blktrans_dev *dev;
 180         struct request *req = NULL;
 181
 182         dev = rq->queuedata;
 183
 184         if (!dev)
 185                 while ((req = blk_fetch_request(rq)) != NULL)
 186                         __blk_end_request_all(req, -ENODEV);
 187         else
 188                 wake_up_process(dev->thread);
 189 }
 190
 191 static int blktrans_open(struct block_device *bdev, fmode_t mode)
 192 {
 193         struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
 194         int ret;
 195
 196         if (!dev)
 197                 return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
 198
 199         lock_kernel();
 200         mutex_lock(&dev->lock);
 201
 202         if (!dev->mtd) {
 203                 ret = -ENXIO;
 204                 goto unlock;
 205         }
 206
 207         ret = !dev->open++ && dev->tr->open ? dev->tr->open(dev) : 0;
 208
 209         /* Take another reference on the device so it won't go away till
 210                 last release */
 211         if (!ret)
 212                 kref_get(&dev->ref);
 213 unlock:
 214         mutex_unlock(&dev->lock);
 215         blktrans_dev_put(dev);
 216         unlock_kernel();
 217         return ret;
 218 }
 219
 220 static int blktrans_release(struct gendisk *disk, fmode_t mode)
 221 {
 222         struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
 223         int ret = -ENXIO;
 224
 225         if (!dev)
 226                 return ret;
 227
 228         lock_kernel();
 229         mutex_lock(&dev->lock);
 230
 231         /* Release one reference, we sure its not the last one here*/
 232         kref_put(&dev->ref, blktrans_dev_release);
 233
 234         if (!dev->mtd)
 235                 goto unlock;
 236
 237         ret = !--dev->open && dev->tr->release ? dev->tr->release(dev) : 0;
 238 unlock:
 239         mutex_unlock(&dev->lock);
 240         blktrans_dev_put(dev);
 241         unlock_kernel();
 242         return ret;
 243 }
 244
 245 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 246 {
 247         struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
 248         int ret = -ENXIO;
 249
 250         if (!dev)
 251                 return ret;
 252
 253         mutex_lock(&dev->lock);
 254
 255         if (!dev->mtd)
 256                 goto unlock;
 257
 258         ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0;
 259 unlock:
 260         mutex_unlock(&dev->lock);
 261         blktrans_dev_put(dev);
 262         return ret;
 263 }
 264
 265 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
 266                               unsigned int cmd, unsigned long arg)
 267 {
 268         struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
 269         int ret = -ENXIO;
 270
 271         if (!dev)
 272                 return ret;
 273
 274         lock_kernel();
 275         mutex_lock(&dev->lock);
 276
 277         if (!dev->mtd)
 278                 goto unlock;
 279
 280         switch (cmd) {
 281         case BLKFLSBUF:
 282                 ret = dev->tr->flush ? dev->tr->flush(dev) : 0;
 283                 break;
 284         default:
 285                 ret = -ENOTTY;
 286         }
 287 unlock:
 288         mutex_unlock(&dev->lock);
 289         unlock_kernel();
 290         blktrans_dev_put(dev);
 291         return ret;
 292 }
 293
 294 static const struct block_device_operations mtd_blktrans_ops = {
 295         .owner          = THIS_MODULE,
 296         .open           = blktrans_open,
 297         .release        = blktrans_release,
 298         .ioctl          = blktrans_ioctl,
 299         .getgeo         = blktrans_getgeo,
 300 };
 301
 302 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 303 {
 304         struct mtd_blktrans_ops *tr = new->tr;
 305         struct mtd_blktrans_dev *d;
 306         int last_devnum = -1;
 307         struct gendisk *gd;
 308         int ret;
 309
 310         if (mutex_trylock(&mtd_table_mutex)) {
 311                 mutex_unlock(&mtd_table_mutex);
 312                 BUG();
 313         }
 314
 315         mutex_lock(&blktrans_ref_mutex);
 316         list_for_each_entry(d, &tr->devs, list) {
 317                 if (new->devnum == -1) {
 318                         /* Use first free number */
 319                         if (d->devnum != last_devnum+1) {
 320                                 /* Found a free devnum. Plug it in here */
 321                                 new->devnum = last_devnum+1;
 322                                 list_add_tail(&new->list, &d->list);
 323                                 goto added;
 324                         }
 325                 } else if (d->devnum == new->devnum) {
 326                         /* Required number taken */
 327                         mutex_unlock(&blktrans_ref_mutex);
 328                         return -EBUSY;
 329                 } else if (d->devnum > new->devnum) {
 330                         /* Required number was free */
 331                         list_add_tail(&new->list, &d->list);
 332                         goto added;
 333                 }
 334                 last_devnum = d->devnum;
 335         }
 336
 337         ret = -EBUSY;
 338         if (new->devnum == -1)
 339                 new->devnum = last_devnum+1;
 340
 341         /* Check that the device and any partitions will get valid
 342          * minor numbers and that the disk naming code below can cope
 343          * with this number. */
 344         if (new->devnum > (MINORMASK >> tr->part_bits) ||
 345             (tr->part_bits && new->devnum >= 27 * 26)) {
 346                 mutex_unlock(&blktrans_ref_mutex);
 347                 goto error1;
 348         }
 349
 350         list_add_tail(&new->list, &tr->devs);
 351  added:
 352         mutex_unlock(&blktrans_ref_mutex);
 353
 354         mutex_init(&new->lock);
 355         kref_init(&new->ref);
 356         if (!tr->writesect)
 357                 new->readonly = 1;
 358
 359         /* Create gendisk */
 360         ret = -ENOMEM;
 361         gd = alloc_disk(1 << tr->part_bits);
 362
 363         if (!gd)
 364                 goto error2;
 365
 366         new->disk = gd;
 367         gd->private_data = new;
 368         gd->major = tr->major;
 369         gd->first_minor = (new->devnum) << tr->part_bits;
 370         gd->fops = &mtd_blktrans_ops;
 371
 372         if (tr->part_bits)
 373                 if (new->devnum < 26)
 374                         snprintf(gd->disk_name, sizeof(gd->disk_name),
 375                                  "%s%c", tr->name, 'a' + new->devnum);
 376                 else
 377                         snprintf(gd->disk_name, sizeof(gd->disk_name),
 378                                  "%s%c%c", tr->name,
 379                                  'a' - 1 + new->devnum / 26,
 380                                  'a' + new->devnum % 26);
 381         else
 382                 snprintf(gd->disk_name, sizeof(gd->disk_name),
 383                          "%s%d", tr->name, new->devnum);
 384
 385         /* 2.5 has capacity in units of 512 bytes while still
 386            having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
 387         //set_capacity(gd, (new->size * tr->blksize) >> 9);
 388         set_capacity(gd, (new->size >> 9) * tr->blksize);   //modify by zyf for cap>=4GB 20110120
 389
 390         /* Create the request queue */
 391         spin_lock_init(&new->queue_lock);
 392         new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
 393
 394         if (!new->rq)
 395                 goto error3;
 396
 397         new->rq->queuedata = new;
 398         blk_queue_logical_block_size(new->rq, tr->blksize);
 399
 400         if (tr->discard)
 401                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
 402                                         new->rq);
 403
 404         gd->queue = new->rq;
 405
 406         __get_mtd_device(new->mtd);
 407         __module_get(tr->owner);
 408
 409         /* Create processing thread */
 410         /* TODO: workqueue ? */
 411         new->thread = kthread_run(mtd_blktrans_thread, new,
 412                         "%s%d", tr->name, new->mtd->index);
 413         if (IS_ERR(new->thread)) {
 414                 ret = PTR_ERR(new->thread);
 415                 goto error4;
 416         }
 417         gd->driverfs_dev = &new->mtd->dev;
 418
 419         if (new->readonly)
 420                 set_disk_ro(gd, 1);
 421
 422         add_disk(gd);
 423
 424         if (new->disk_attributes) {
 425                 ret = sysfs_create_group(&disk_to_dev(gd)->kobj,
 426                                         new->disk_attributes);
 427                 WARN_ON(ret);
 428         }
 429         return 0;
 430 error4:
 431         module_put(tr->owner);
 432         __put_mtd_device(new->mtd);
 433         blk_cleanup_queue(new->rq);
 434 error3:
 435         put_disk(new->disk);
 436 error2:
 437         list_del(&new->list);
 438 error1:
 439         kfree(new);
 440         return ret;
 441 }
 442
 443 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
 444 {
 445         unsigned long flags;
 446
 447         if (mutex_trylock(&mtd_table_mutex)) {
 448                 mutex_unlock(&mtd_table_mutex);
 449                 BUG();
 450         }
 451
 452         if (old->disk_attributes)
 453                 sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
 454                                                 old->disk_attributes);
 455
 456         /* Stop new requests to arrive */
 457         del_gendisk(old->disk);
 458
 459
 460         /* Stop the thread */
 461         kthread_stop(old->thread);
 462
 463         /* Kill current requests */
 464         spin_lock_irqsave(&old->queue_lock, flags);
 465         old->rq->queuedata = NULL;
 466         blk_start_queue(old->rq);
 467         spin_unlock_irqrestore(&old->queue_lock, flags);
 468
 469         /* Ask trans driver for release to the mtd device */
 470         mutex_lock(&old->lock);
 471         if (old->open && old->tr->release) {
 472                 old->tr->release(old);
 473                 old->open = 0;
 474         }
 475
 476         __put_mtd_device(old->mtd);
 477         module_put(old->tr->owner);
 478
 479         /* At that point, we don't touch the mtd anymore */
 480         old->mtd = NULL;
 481
 482         mutex_unlock(&old->lock);
 483         blktrans_dev_put(old);
 484         return 0;
 485 }
 486
 487 static void blktrans_notify_remove(struct mtd_info *mtd)
 488 {
 489         struct mtd_blktrans_ops *tr;
 490         struct mtd_blktrans_dev *dev, *next;
 491
 492         list_for_each_entry(tr, &blktrans_majors, list)
 493                 list_for_each_entry_safe(dev, next, &tr->devs, list)
 494                         if (dev->mtd == mtd)
 495                                 tr->remove_dev(dev);
 496 }
 497
 498 static void blktrans_notify_add(struct mtd_info *mtd)
 499 {
 500         struct mtd_blktrans_ops *tr;
 501
 502         if (mtd->type == MTD_ABSENT)
 503                 return;
 504
 505         list_for_each_entry(tr, &blktrans_majors, list)
 506                 tr->add_mtd(tr, mtd);
 507 }
 508
 509 static struct mtd_notifier blktrans_notifier = {
 510         .add = blktrans_notify_add,
 511         .remove = blktrans_notify_remove,
 512 };
 513
 514 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
 515 {
 516         struct mtd_info *mtd;
 517         int ret;
 518
 519         /* Register the notifier if/when the first device type is
 520            registered, to prevent the link/init ordering from fucking
 521            us over. */
 522         if (!blktrans_notifier.list.next)
 523                 register_mtd_user(&blktrans_notifier);
 524
 525
 526         mutex_lock(&mtd_table_mutex);
 527
 528         ret = register_blkdev(tr->major, tr->name);
 529         if (ret) {
 530                 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
 531                        tr->name, tr->major, ret);
 532                 mutex_unlock(&mtd_table_mutex);
 533                 return ret;
 534         }
 535
 536         tr->blkshift = ffs(tr->blksize) - 1;
 537
 538         INIT_LIST_HEAD(&tr->devs);
 539         list_add(&tr->list, &blktrans_majors);
 540
 541         mtd_for_each_device(mtd)
 542                 if (mtd->type != MTD_ABSENT)
 543                         tr->add_mtd(tr, mtd);
 544
 545         mutex_unlock(&mtd_table_mutex);
 546         return 0;
 547 }
 548
 549 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
 550 {
 551         struct mtd_blktrans_dev *dev, *next;
 552
 553         mutex_lock(&mtd_table_mutex);
 554
 555         /* Remove it from the list of active majors */
 556         list_del(&tr->list);
 557
 558         list_for_each_entry_safe(dev, next, &tr->devs, list)
 559                 tr->remove_dev(dev);
 560
 561         unregister_blkdev(tr->major, tr->name);
 562         mutex_unlock(&mtd_table_mutex);
 563
 564         BUG_ON(!list_empty(&tr->devs));
 565         return 0;
 566 }
 567
 568 static void __exit mtd_blktrans_exit(void)
 569 {
 570         /* No race here -- if someone's currently in register_mtd_blktrans
 571            we're screwed anyway. */
 572         if (blktrans_notifier.list.next)
 573                 unregister_mtd_user(&blktrans_notifier);
 574 }
 575
 576 module_exit(mtd_blktrans_exit);
 577
 578 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
 579 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
 580 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
 581 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
 582
 583 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 584 MODULE_LICENSE("GPL");
 585 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");