drivers/mtd/mtd_blkdevs.c

   1 /*
   2  * (C) 2003 David Woodhouse <dwmw2@infradead.org>
   3  *
   4  * Interface to Linux 2.5 block layer for MTD 'translation layers'.
   5  *
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/slab.h>
  10 #include <linux/module.h>
  11 #include <linux/list.h>
  12 #include <linux/fs.h>
  13 #include <linux/mtd/blktrans.h>
  14 #include <linux/mtd/mtd.h>
  15 #include <linux/blkdev.h>
  16 #include <linux/blkpg.h>
  17 #include <linux/freezer.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/hdreg.h>
  20 #include <linux/init.h>
  21 #include <linux/mutex.h>
  22 #include <linux/kthread.h>
  23 #include <asm/uaccess.h>
  24
  25 #include "mtdcore.h"
  26
  27 static LIST_HEAD(blktrans_majors);
  28
  29 struct mtd_blkcore_priv {
  30         struct task_struct *thread;
  31         struct request_queue *rq;
  32         spinlock_t queue_lock;
  33 };
  34
  35 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
  36                                struct mtd_blktrans_dev *dev,
  37                                struct request *req)
  38 {
  39         unsigned long block, nsect;
  40         char *buf;
  41 #if 0
  42         block = blk_rq_pos(req) << 9 >> tr->blkshift;
  43         nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
  44 #else  //modify by zyf for cap>=4GB 20110120
  45         block = blk_rq_pos(req);
  46         nsect = blk_rq_cur_bytes(req) >> tr->blkshift;
  47     if(tr->blkshift != 9)
  48     {
  49         if(tr->blkshift > 9)
  50         {
  51             block = blk_rq_pos(req) >> (tr->blkshift - 9);
  52         }
  53         else
  54         {
  55                 block = blk_rq_pos(req) << (9 - tr->blkshift);
  56         }
  57     }
  58 #endif
  59
  60         buf = req->buffer;
  61
  62         if (!blk_fs_request(req))
  63                 return -EIO;
  64
  65         if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
  66             get_capacity(req->rq_disk))
  67                 return -EIO;
  68
  69         if (blk_discard_rq(req))
  70                 return tr->discard(dev, block, nsect);
  71
  72         switch(rq_data_dir(req)) {
  73         case READ:
  74                 //for (; nsect > 0; nsect--, block++, buf += tr->blksize)
  75                         if (tr->readsect(dev, block,nsect, buf))
  76                                 return -EIO;
  77                 return 0;
  78
  79         case WRITE:
  80                 if (!tr->writesect)
  81                         return -EIO;
  82
  83                 //for (; nsect > 0; nsect--, block++, buf += tr->blksize)
  84                         if (tr->writesect(dev, block,nsect, buf))
  85                                 return -EIO;
  86                 return 0;
  87
  88         default:
  89                 printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req));
  90                 return -EIO;
  91         }
  92 }
  93
  94 static int mtd_blktrans_thread(void *arg)
  95 {
  96         struct mtd_blktrans_ops *tr = arg;
  97         struct request_queue *rq = tr->blkcore_priv->rq;
  98         struct request *req = NULL;
  99
 100         /* we might get involved when memory gets low, so use PF_MEMALLOC */
 101         current->flags |= PF_MEMALLOC;
 102
 103         spin_lock_irq(rq->queue_lock);
 104
 105         while (!kthread_should_stop()) {
 106                 struct mtd_blktrans_dev *dev;
 107                 int res;
 108
 109                 if (!req && !(req = blk_fetch_request(rq))) {
 110                         set_current_state(TASK_INTERRUPTIBLE);
 111                         spin_unlock_irq(rq->queue_lock);
 112                         schedule();
 113                         spin_lock_irq(rq->queue_lock);
 114                         continue;
 115                 }
 116
 117                 dev = req->rq_disk->private_data;
 118                 tr = dev->tr;
 119
 120                 spin_unlock_irq(rq->queue_lock);
 121
 122                 mutex_lock(&dev->lock);
 123                 res = do_blktrans_request(tr, dev, req);
 124                 mutex_unlock(&dev->lock);
 125
 126                 spin_lock_irq(rq->queue_lock);
 127
 128                 if (!__blk_end_request_cur(req, res))
 129                         req = NULL;
 130         }
 131
 132         if (req)
 133                 __blk_end_request_all(req, -EIO);
 134
 135         spin_unlock_irq(rq->queue_lock);
 136
 137         return 0;
 138 }
 139
 140 static void mtd_blktrans_request(struct request_queue *rq)
 141 {
 142         struct mtd_blktrans_ops *tr = rq->queuedata;
 143         wake_up_process(tr->blkcore_priv->thread);
 144 }
 145
 146
 147 static int blktrans_open(struct block_device *bdev, fmode_t mode)
 148 {
 149         struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
 150         struct mtd_blktrans_ops *tr = dev->tr;
 151         int ret = -ENODEV;
 152
 153         if (!get_mtd_device(NULL, dev->mtd->index))
 154                 goto out;
 155
 156         if (!try_module_get(tr->owner))
 157                 goto out_tr;
 158
 159         /* FIXME: Locking. A hot pluggable device can go away
 160            (del_mtd_device can be called for it) without its module
 161            being unloaded. */
 162         dev->mtd->usecount++;
 163
 164         ret = 0;
 165         if (tr->open && (ret = tr->open(dev))) {
 166                 dev->mtd->usecount--;
 167                 put_mtd_device(dev->mtd);
 168         out_tr:
 169                 module_put(tr->owner);
 170         }
 171  out:
 172         return ret;
 173 }
 174
 175 static int blktrans_release(struct gendisk *disk, fmode_t mode)
 176 {
 177         struct mtd_blktrans_dev *dev = disk->private_data;
 178         struct mtd_blktrans_ops *tr = dev->tr;
 179         int ret = 0;
 180
 181         if (tr->release)
 182                 ret = tr->release(dev);
 183
 184         if (!ret) {
 185                 dev->mtd->usecount--;
 186                 put_mtd_device(dev->mtd);
 187                 module_put(tr->owner);
 188         }
 189
 190         return ret;
 191 }
 192
 193 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 194 {
 195         struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
 196
 197         if (dev->tr->getgeo)
 198                 return dev->tr->getgeo(dev, geo);
 199         return -ENOTTY;
 200 }
 201
 202 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
 203                               unsigned int cmd, unsigned long arg)
 204 {
 205         struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
 206         struct mtd_blktrans_ops *tr = dev->tr;
 207
 208         switch (cmd) {
 209         case BLKFLSBUF:
 210                 if (tr->flush)
 211                         return tr->flush(dev);
 212                 /* The core code did the work, we had nothing to do. */
 213                 return 0;
 214         default:
 215                 return -ENOTTY;
 216         }
 217 }
 218
 219 static const struct block_device_operations mtd_blktrans_ops = {
 220         .owner          = THIS_MODULE,
 221         .open           = blktrans_open,
 222         .release        = blktrans_release,
 223         .locked_ioctl   = blktrans_ioctl,
 224         .getgeo         = blktrans_getgeo,
 225 };
 226
 227 int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 228 {
 229         struct mtd_blktrans_ops *tr = new->tr;
 230         struct mtd_blktrans_dev *d;
 231         int last_devnum = -1;
 232         struct gendisk *gd;
 233
 234         if (mutex_trylock(&mtd_table_mutex)) {
 235                 mutex_unlock(&mtd_table_mutex);
 236                 BUG();
 237         }
 238
 239         list_for_each_entry(d, &tr->devs, list) {
 240                 if (new->devnum == -1) {
 241                         /* Use first free number */
 242                         if (d->devnum != last_devnum+1) {
 243                                 /* Found a free devnum. Plug it in here */
 244                                 new->devnum = last_devnum+1;
 245                                 list_add_tail(&new->list, &d->list);
 246                                 goto added;
 247                         }
 248                 } else if (d->devnum == new->devnum) {
 249                         /* Required number taken */
 250                         return -EBUSY;
 251                 } else if (d->devnum > new->devnum) {
 252                         /* Required number was free */
 253                         list_add_tail(&new->list, &d->list);
 254                         goto added;
 255                 }
 256                 last_devnum = d->devnum;
 257         }
 258         if (new->devnum == -1)
 259                 new->devnum = last_devnum+1;
 260
 261         if ((new->devnum << tr->part_bits) > 256) {
 262                 return -EBUSY;
 263         }
 264
 265         list_add_tail(&new->list, &tr->devs);
 266  added:
 267         mutex_init(&new->lock);
 268         if (!tr->writesect)
 269                 new->readonly = 1;
 270
 271         gd = alloc_disk(1 << tr->part_bits);
 272         if (!gd) {
 273                 list_del(&new->list);
 274                 return -ENOMEM;
 275         }
 276         gd->major = tr->major;
 277         gd->first_minor = (new->devnum) << tr->part_bits;
 278         gd->fops = &mtd_blktrans_ops;
 279
 280         if (tr->part_bits)
 281                 if (new->devnum < 26)
 282                         snprintf(gd->disk_name, sizeof(gd->disk_name),
 283                                  "%s%c", tr->name, 'a' + new->devnum);
 284                 else
 285                         snprintf(gd->disk_name, sizeof(gd->disk_name),
 286                                  "%s%c%c", tr->name,
 287                                  'a' - 1 + new->devnum / 26,
 288                                  'a' + new->devnum % 26);
 289         else
 290                 snprintf(gd->disk_name, sizeof(gd->disk_name),
 291                          "%s%d", tr->name, new->devnum);
 292
 293         /* 2.5 has capacity in units of 512 bytes while still
 294            having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
 295         //set_capacity(gd, (new->size * tr->blksize) >> 9);
 296         set_capacity(gd, (new->size >> 9) * tr->blksize);   //modify by zyf for cap>=4GB 20110120
 297
 298         gd->private_data = new;
 299         new->blkcore_priv = gd;
 300         gd->queue = tr->blkcore_priv->rq;
 301         gd->driverfs_dev = &new->mtd->dev;
 302
 303         if (new->readonly)
 304                 set_disk_ro(gd, 1);
 305
 306         add_disk(gd);
 307
 308         return 0;
 309 }
 310
 311 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
 312 {
 313         if (mutex_trylock(&mtd_table_mutex)) {
 314                 mutex_unlock(&mtd_table_mutex);
 315                 BUG();
 316         }
 317
 318         list_del(&old->list);
 319
 320         del_gendisk(old->blkcore_priv);
 321         put_disk(old->blkcore_priv);
 322
 323         return 0;
 324 }
 325
 326 static void blktrans_notify_remove(struct mtd_info *mtd)
 327 {
 328         struct mtd_blktrans_ops *tr;
 329         struct mtd_blktrans_dev *dev, *next;
 330
 331         list_for_each_entry(tr, &blktrans_majors, list)
 332                 list_for_each_entry_safe(dev, next, &tr->devs, list)
 333                         if (dev->mtd == mtd)
 334                                 tr->remove_dev(dev);
 335 }
 336
 337 static void blktrans_notify_add(struct mtd_info *mtd)
 338 {
 339         struct mtd_blktrans_ops *tr;
 340
 341         if (mtd->type == MTD_ABSENT)
 342                 return;
 343
 344         list_for_each_entry(tr, &blktrans_majors, list)
 345                 tr->add_mtd(tr, mtd);
 346 }
 347
 348 static struct mtd_notifier blktrans_notifier = {
 349         .add = blktrans_notify_add,
 350         .remove = blktrans_notify_remove,
 351 };
 352
 353 int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
 354 {
 355         int ret, i;
 356
 357         /* Register the notifier if/when the first device type is
 358            registered, to prevent the link/init ordering from fucking
 359            us over. */
 360         if (!blktrans_notifier.list.next)
 361                 register_mtd_user(&blktrans_notifier);
 362
 363         tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
 364         if (!tr->blkcore_priv)
 365                 return -ENOMEM;
 366
 367         mutex_lock(&mtd_table_mutex);
 368
 369         ret = register_blkdev(tr->major, tr->name);
 370         if (ret) {
 371                 printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
 372                        tr->name, tr->major, ret);
 373                 kfree(tr->blkcore_priv);
 374                 mutex_unlock(&mtd_table_mutex);
 375                 return ret;
 376         }
 377         spin_lock_init(&tr->blkcore_priv->queue_lock);
 378
 379         tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
 380         if (!tr->blkcore_priv->rq) {
 381                 unregister_blkdev(tr->major, tr->name);
 382                 kfree(tr->blkcore_priv);
 383                 mutex_unlock(&mtd_table_mutex);
 384                 return -ENOMEM;
 385         }
 386
 387         tr->blkcore_priv->rq->queuedata = tr;
 388         blk_queue_logical_block_size(tr->blkcore_priv->rq, tr->blksize);
 389         if (tr->discard)
 390                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
 391                                         tr->blkcore_priv->rq);
 392
 393         tr->blkshift = ffs(tr->blksize) - 1;
 394
 395         tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
 396                         "%sd", tr->name);
 397         if (IS_ERR(tr->blkcore_priv->thread)) {
 398                 int ret = PTR_ERR(tr->blkcore_priv->thread);
 399                 blk_cleanup_queue(tr->blkcore_priv->rq);
 400                 unregister_blkdev(tr->major, tr->name);
 401                 kfree(tr->blkcore_priv);
 402                 mutex_unlock(&mtd_table_mutex);
 403                 return ret;
 404         }
 405
 406         INIT_LIST_HEAD(&tr->devs);
 407         list_add(&tr->list, &blktrans_majors);
 408
 409         for (i=0; i<MAX_MTD_DEVICES; i++) {
 410                 if (mtd_table[i] && mtd_table[i]->type != MTD_ABSENT)
 411                         tr->add_mtd(tr, mtd_table[i]);
 412         }
 413
 414         mutex_unlock(&mtd_table_mutex);
 415
 416         return 0;
 417 }
 418
 419 int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
 420 {
 421         struct mtd_blktrans_dev *dev, *next;
 422
 423         mutex_lock(&mtd_table_mutex);
 424
 425         /* Clean up the kernel thread */
 426         kthread_stop(tr->blkcore_priv->thread);
 427
 428         /* Remove it from the list of active majors */
 429         list_del(&tr->list);
 430
 431         list_for_each_entry_safe(dev, next, &tr->devs, list)
 432                 tr->remove_dev(dev);
 433
 434         blk_cleanup_queue(tr->blkcore_priv->rq);
 435         unregister_blkdev(tr->major, tr->name);
 436
 437         mutex_unlock(&mtd_table_mutex);
 438
 439         kfree(tr->blkcore_priv);
 440
 441         BUG_ON(!list_empty(&tr->devs));
 442         return 0;
 443 }
 444
 445 static void __exit mtd_blktrans_exit(void)
 446 {
 447         /* No race here -- if someone's currently in register_mtd_blktrans
 448            we're screwed anyway. */
 449         if (blktrans_notifier.list.next)
 450                 unregister_mtd_user(&blktrans_notifier);
 451 }
 452
 453 module_exit(mtd_blktrans_exit);
 454
 455 EXPORT_SYMBOL_GPL(register_mtd_blktrans);
 456 EXPORT_SYMBOL_GPL(deregister_mtd_blktrans);
 457 EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev);
 458 EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev);
 459
 460 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 461 MODULE_LICENSE("GPL");
 462 MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'");