2 * Copyright (c) 2014 Ezequiel Garcia
3 * Copyright (c) 2011 Free Electrons
5 * Driver parameter handling strongly based on drivers/mtd/ubi/build.c
6 * Copyright (c) International Business Machines Corp., 2006
7 * Copyright (c) Nokia Corporation, 2007
8 * Authors: Artem Bityutskiy, Frank Haverkamp
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation, version 2.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
17 * the GNU General Public License for more details.
21 * Read-only block devices on top of UBI volumes
23 * A simple implementation to allow a block device to be layered on top of a
24 * UBI volume. The implementation is provided by creating a static 1-to-1
25 * mapping between the block device and the UBI volume.
27 * The addressed byte is obtained from the addressed block sector, which is
28 * mapped linearly into the corresponding LEB:
30 * LEB number = addressed byte / LEB size
32 * This feature is compiled in the UBI core, and adds a 'block' parameter
33 * to allow early creation of block devices on top of UBI volumes. Runtime
34 * block creation/removal for UBI volumes is provided through two UBI ioctls:
35 * UBI_IOCVOLCRBLK and UBI_IOCVOLRMBLK.
38 #include <linux/module.h>
39 #include <linux/init.h>
40 #include <linux/err.h>
41 #include <linux/kernel.h>
42 #include <linux/list.h>
43 #include <linux/mutex.h>
44 #include <linux/slab.h>
45 #include <linux/vmalloc.h>
46 #include <linux/mtd/ubi.h>
47 #include <linux/workqueue.h>
48 #include <linux/blkdev.h>
49 #include <linux/hdreg.h>
50 #include <asm/div64.h>
52 #include "ubi-media.h"
55 /* Maximum number of supported devices */
56 #define UBIBLOCK_MAX_DEVICES 32
58 /* Maximum length of the 'block=' parameter */
59 #define UBIBLOCK_PARAM_LEN 63
61 /* Maximum number of comma-separated items in the 'block=' parameter */
62 #define UBIBLOCK_PARAM_COUNT 2
64 struct ubiblock_param {
67 char name[UBIBLOCK_PARAM_LEN+1];
70 /* Numbers of elements set in the @ubiblock_param array */
71 static int ubiblock_devs __initdata;
73 /* MTD devices specification parameters */
74 static struct ubiblock_param ubiblock_param[UBIBLOCK_MAX_DEVICES] __initdata;
77 struct ubi_volume_desc *desc;
84 struct request_queue *rq;
86 struct workqueue_struct *wq;
87 struct work_struct work;
89 struct mutex dev_mutex;
90 spinlock_t queue_lock;
91 struct list_head list;
94 /* Linked list of all ubiblock instances */
95 static LIST_HEAD(ubiblock_devices);
96 static DEFINE_MUTEX(devices_mutex);
97 static int ubiblock_major;
99 static int __init ubiblock_set_param(const char *val,
100 const struct kernel_param *kp)
104 struct ubiblock_param *param;
105 char buf[UBIBLOCK_PARAM_LEN];
106 char *pbuf = &buf[0];
107 char *tokens[UBIBLOCK_PARAM_COUNT];
112 len = strnlen(val, UBIBLOCK_PARAM_LEN);
114 ubi_warn("block: empty 'block=' parameter - ignored\n");
118 if (len == UBIBLOCK_PARAM_LEN) {
119 ubi_err("block: parameter \"%s\" is too long, max. is %d\n",
120 val, UBIBLOCK_PARAM_LEN);
126 /* Get rid of the final newline */
127 if (buf[len - 1] == '\n')
130 for (i = 0; i < UBIBLOCK_PARAM_COUNT; i++)
131 tokens[i] = strsep(&pbuf, ",");
133 param = &ubiblock_param[ubiblock_devs];
135 /* Two parameters: can be 'ubi, vol_id' or 'ubi, vol_name' */
136 ret = kstrtoint(tokens[0], 10, ¶m->ubi_num);
140 /* Second param can be a number or a name */
141 ret = kstrtoint(tokens[1], 10, ¶m->vol_id);
144 strcpy(param->name, tokens[1]);
148 /* One parameter: must be device path */
149 strcpy(param->name, tokens[0]);
159 static struct kernel_param_ops ubiblock_param_ops = {
160 .set = ubiblock_set_param,
162 module_param_cb(block, &ubiblock_param_ops, NULL, 0);
163 MODULE_PARM_DESC(block, "Attach block devices to UBI volumes. Parameter format: block=<path|dev,num|dev,name>.\n"
164 "Multiple \"block\" parameters may be specified.\n"
165 "UBI volumes may be specified by their number, name, or path to the device node.\n"
167 "Using the UBI volume path:\n"
168 "ubi.block=/dev/ubi0_0\n"
169 "Using the UBI device, and the volume name:\n"
170 "ubi.block=0,rootfs\n"
171 "Using both UBI device number and UBI volume number:\n"
174 static struct ubiblock *find_dev_nolock(int ubi_num, int vol_id)
176 struct ubiblock *dev;
178 list_for_each_entry(dev, &ubiblock_devices, list)
179 if (dev->ubi_num == ubi_num && dev->vol_id == vol_id)
184 static int ubiblock_read_to_buf(struct ubiblock *dev, char *buffer,
185 int leb, int offset, int len)
189 ret = ubi_read(dev->desc, leb, buffer, offset, len);
191 ubi_err("%s ubi_read error %d",
192 dev->gd->disk_name, ret);
198 static int ubiblock_read(struct ubiblock *dev, char *buffer,
199 sector_t sec, int len)
201 int ret, leb, offset;
202 int bytes_left = len;
206 /* Get LEB:offset address to read from */
207 offset = do_div(pos, dev->leb_size);
212 * We can only read one LEB at a time. Therefore if the read
213 * length is larger than one LEB size, we split the operation.
215 if (offset + to_read > dev->leb_size)
216 to_read = dev->leb_size - offset;
218 ret = ubiblock_read_to_buf(dev, buffer, leb, offset, to_read);
223 bytes_left -= to_read;
224 to_read = bytes_left;
231 static int do_ubiblock_request(struct ubiblock *dev, struct request *req)
236 if (req->cmd_type != REQ_TYPE_FS)
239 if (blk_rq_pos(req) + blk_rq_cur_sectors(req) >
240 get_capacity(req->rq_disk))
243 if (rq_data_dir(req) != READ)
244 return -ENOSYS; /* Write not implemented */
246 sec = blk_rq_pos(req);
247 len = blk_rq_cur_bytes(req);
250 * Let's prevent the device from being removed while we're doing I/O
251 * work. Notice that this means we serialize all the I/O operations,
252 * but it's probably of no impact given the NAND core serializes
253 * flash access anyway.
255 mutex_lock(&dev->dev_mutex);
256 ret = ubiblock_read(dev, bio_data(req->bio), sec, len);
257 mutex_unlock(&dev->dev_mutex);
262 static void ubiblock_do_work(struct work_struct *work)
264 struct ubiblock *dev =
265 container_of(work, struct ubiblock, work);
266 struct request_queue *rq = dev->rq;
270 spin_lock_irq(rq->queue_lock);
272 req = blk_fetch_request(rq);
275 spin_unlock_irq(rq->queue_lock);
276 res = do_ubiblock_request(dev, req);
277 spin_lock_irq(rq->queue_lock);
280 * If we're done with this request,
281 * we need to fetch a new one
283 if (!__blk_end_request_cur(req, res))
284 req = blk_fetch_request(rq);
287 spin_unlock_irq(rq->queue_lock);
290 static void ubiblock_request(struct request_queue *rq)
292 struct ubiblock *dev;
298 while ((req = blk_fetch_request(rq)) != NULL)
299 __blk_end_request_all(req, -ENODEV);
301 queue_work(dev->wq, &dev->work);
304 static int ubiblock_open(struct block_device *bdev, fmode_t mode)
306 struct ubiblock *dev = bdev->bd_disk->private_data;
309 mutex_lock(&dev->dev_mutex);
310 if (dev->refcnt > 0) {
312 * The volume is already open, just increase the reference
319 * We want users to be aware they should only mount us as read-only.
320 * It's just a paranoid check, as write requests will get rejected
323 if (mode & FMODE_WRITE) {
328 dev->desc = ubi_open_volume(dev->ubi_num, dev->vol_id, UBI_READONLY);
329 if (IS_ERR(dev->desc)) {
330 ubi_err("%s failed to open ubi volume %d_%d",
331 dev->gd->disk_name, dev->ubi_num, dev->vol_id);
332 ret = PTR_ERR(dev->desc);
339 mutex_unlock(&dev->dev_mutex);
343 mutex_unlock(&dev->dev_mutex);
347 static void ubiblock_release(struct gendisk *gd, fmode_t mode)
349 struct ubiblock *dev = gd->private_data;
351 mutex_lock(&dev->dev_mutex);
353 if (dev->refcnt == 0) {
354 ubi_close_volume(dev->desc);
357 mutex_unlock(&dev->dev_mutex);
360 static int ubiblock_getgeo(struct block_device *bdev, struct hd_geometry *geo)
362 /* Some tools might require this information */
365 geo->sectors = get_capacity(bdev->bd_disk);
370 static const struct block_device_operations ubiblock_ops = {
371 .owner = THIS_MODULE,
372 .open = ubiblock_open,
373 .release = ubiblock_release,
374 .getgeo = ubiblock_getgeo,
377 int ubiblock_create(struct ubi_volume_info *vi)
379 struct ubiblock *dev;
384 /* Check that the volume isn't already handled */
385 mutex_lock(&devices_mutex);
386 if (find_dev_nolock(vi->ubi_num, vi->vol_id)) {
387 mutex_unlock(&devices_mutex);
390 mutex_unlock(&devices_mutex);
392 dev = kzalloc(sizeof(struct ubiblock), GFP_KERNEL);
396 mutex_init(&dev->dev_mutex);
398 dev->ubi_num = vi->ubi_num;
399 dev->vol_id = vi->vol_id;
400 dev->leb_size = vi->usable_leb_size;
402 /* Initialize the gendisk of this ubiblock device */
405 ubi_err("block: alloc_disk failed");
410 gd->fops = &ubiblock_ops;
411 gd->major = ubiblock_major;
412 gd->first_minor = dev->ubi_num * UBI_MAX_VOLUMES + dev->vol_id;
413 gd->private_data = dev;
414 sprintf(gd->disk_name, "ubiblock%d_%d", dev->ubi_num, dev->vol_id);
415 disk_capacity = (vi->size * vi->usable_leb_size) >> 9;
416 set_capacity(gd, disk_capacity);
419 spin_lock_init(&dev->queue_lock);
420 dev->rq = blk_init_queue(ubiblock_request, &dev->queue_lock);
422 ubi_err("block: blk_init_queue failed");
427 dev->rq->queuedata = dev;
428 dev->gd->queue = dev->rq;
431 * Create one workqueue per volume (per registered block device).
432 * Rembember workqueues are cheap, they're not threads.
434 dev->wq = alloc_workqueue("%s", 0, 0, gd->disk_name);
439 INIT_WORK(&dev->work, ubiblock_do_work);
441 mutex_lock(&devices_mutex);
442 list_add_tail(&dev->list, &ubiblock_devices);
443 mutex_unlock(&devices_mutex);
445 /* Must be the last step: anyone can call file ops from now on */
447 ubi_msg("%s created from ubi%d:%d(%s)",
448 dev->gd->disk_name, dev->ubi_num, dev->vol_id, vi->name);
452 blk_cleanup_queue(dev->rq);
461 static void ubiblock_cleanup(struct ubiblock *dev)
463 del_gendisk(dev->gd);
464 blk_cleanup_queue(dev->rq);
465 ubi_msg("%s released", dev->gd->disk_name);
469 int ubiblock_remove(struct ubi_volume_info *vi)
471 struct ubiblock *dev;
473 mutex_lock(&devices_mutex);
474 dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
476 mutex_unlock(&devices_mutex);
480 /* Found a device, let's lock it so we can check if it's busy */
481 mutex_lock(&dev->dev_mutex);
482 if (dev->refcnt > 0) {
483 mutex_unlock(&dev->dev_mutex);
484 mutex_unlock(&devices_mutex);
488 /* Remove from device list */
489 list_del(&dev->list);
490 mutex_unlock(&devices_mutex);
492 /* Flush pending work and stop this workqueue */
493 destroy_workqueue(dev->wq);
495 ubiblock_cleanup(dev);
496 mutex_unlock(&dev->dev_mutex);
501 static void ubiblock_resize(struct ubi_volume_info *vi)
503 struct ubiblock *dev;
507 * Need to lock the device list until we stop using the device,
508 * otherwise the device struct might get released in
509 * 'ubiblock_remove()'.
511 mutex_lock(&devices_mutex);
512 dev = find_dev_nolock(vi->ubi_num, vi->vol_id);
514 mutex_unlock(&devices_mutex);
518 mutex_lock(&dev->dev_mutex);
519 disk_capacity = (vi->size * vi->usable_leb_size) >> 9;
520 set_capacity(dev->gd, disk_capacity);
521 ubi_msg("%s resized to %d LEBs", dev->gd->disk_name, vi->size);
522 mutex_unlock(&dev->dev_mutex);
523 mutex_unlock(&devices_mutex);
526 static int ubiblock_notify(struct notifier_block *nb,
527 unsigned long notification_type, void *ns_ptr)
529 struct ubi_notification *nt = ns_ptr;
531 switch (notification_type) {
532 case UBI_VOLUME_ADDED:
534 * We want to enforce explicit block device creation for
535 * volumes, so when a volume is added we do nothing.
538 case UBI_VOLUME_REMOVED:
539 ubiblock_remove(&nt->vi);
541 case UBI_VOLUME_RESIZED:
542 ubiblock_resize(&nt->vi);
550 static struct notifier_block ubiblock_notifier = {
551 .notifier_call = ubiblock_notify,
554 static struct ubi_volume_desc * __init
555 open_volume_desc(const char *name, int ubi_num, int vol_id)
558 /* No ubi num, name must be a vol device path */
559 return ubi_open_volume_path(name, UBI_READONLY);
560 else if (vol_id == -1)
561 /* No vol_id, must be vol_name */
562 return ubi_open_volume_nm(ubi_num, name, UBI_READONLY);
564 return ubi_open_volume(ubi_num, vol_id, UBI_READONLY);
567 static int __init ubiblock_create_from_param(void)
570 struct ubiblock_param *p;
571 struct ubi_volume_desc *desc;
572 struct ubi_volume_info vi;
574 for (i = 0; i < ubiblock_devs; i++) {
575 p = &ubiblock_param[i];
577 desc = open_volume_desc(p->name, p->ubi_num, p->vol_id);
579 ubi_err("block: can't open volume, err=%ld\n",
585 ubi_get_volume_info(desc, &vi);
586 ubi_close_volume(desc);
588 ret = ubiblock_create(&vi);
590 ubi_err("block: can't add '%s' volume, err=%d\n",
598 static void ubiblock_remove_all(void)
600 struct ubiblock *next;
601 struct ubiblock *dev;
603 list_for_each_entry_safe(dev, next, &ubiblock_devices, list) {
604 /* Flush pending work and stop workqueue */
605 destroy_workqueue(dev->wq);
606 /* The module is being forcefully removed */
608 /* Remove from device list */
609 list_del(&dev->list);
610 ubiblock_cleanup(dev);
615 int __init ubiblock_init(void)
619 ubiblock_major = register_blkdev(0, "ubiblock");
620 if (ubiblock_major < 0)
621 return ubiblock_major;
623 /* Attach block devices from 'block=' module param */
624 ret = ubiblock_create_from_param();
629 * Block devices are only created upon user requests, so we ignore
632 ret = ubi_register_volume_notifier(&ubiblock_notifier, 1);
638 unregister_blkdev(ubiblock_major, "ubiblock");
640 ubiblock_remove_all();
644 void __exit ubiblock_exit(void)
646 ubi_unregister_volume_notifier(&ubiblock_notifier);
647 ubiblock_remove_all();
648 unregister_blkdev(ubiblock_major, "ubiblock");