From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?= Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- drivers/mtd/mtd_blkdevs.c | 603 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 603 insertions(+) create mode 100644 drivers/mtd/mtd_blkdevs.c (limited to 'drivers/mtd/mtd_blkdevs.c') diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c new file mode 100644 index 000000000..df7c6c707 --- /dev/null +++ b/drivers/mtd/mtd_blkdevs.c @@ -0,0 +1,603 @@ +/* + * Interface to Linux block layer for MTD 'translation layers'. + * + * Copyright © 2003-2010 David Woodhouse + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "mtdcore.h" + +static LIST_HEAD(blktrans_majors); +static DEFINE_MUTEX(blktrans_ref_mutex); + +static void blktrans_dev_release(struct kref *kref) +{ + struct mtd_blktrans_dev *dev = + container_of(kref, struct mtd_blktrans_dev, ref); + + dev->disk->private_data = NULL; + blk_cleanup_queue(dev->rq); + put_disk(dev->disk); + list_del(&dev->list); + kfree(dev); +} + +static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk) +{ + struct mtd_blktrans_dev *dev; + + mutex_lock(&blktrans_ref_mutex); + dev = disk->private_data; + + if (!dev) + goto unlock; + kref_get(&dev->ref); +unlock: + mutex_unlock(&blktrans_ref_mutex); + return dev; +} + +static void blktrans_dev_put(struct mtd_blktrans_dev *dev) +{ + mutex_lock(&blktrans_ref_mutex); + kref_put(&dev->ref, blktrans_dev_release); + mutex_unlock(&blktrans_ref_mutex); +} + + +static int do_blktrans_request(struct mtd_blktrans_ops *tr, + struct mtd_blktrans_dev *dev, + struct request *req) +{ + unsigned long block, nsect; + char *buf; + + block = blk_rq_pos(req) << 9 >> tr->blkshift; + nsect = blk_rq_cur_bytes(req) >> tr->blkshift; + buf = bio_data(req->bio); + + if (req->cmd_type != REQ_TYPE_FS) + return -EIO; + + if (req->cmd_flags & REQ_FLUSH) + return tr->flush(dev); + + if (blk_rq_pos(req) + blk_rq_cur_sectors(req) > + get_capacity(req->rq_disk)) + return -EIO; + + if (req->cmd_flags & REQ_DISCARD) + return tr->discard(dev, block, nsect); + + switch(rq_data_dir(req)) { + case READ: + for (; nsect > 0; nsect--, block++, buf += tr->blksize) + if (tr->readsect(dev, block, buf)) + return -EIO; + rq_flush_dcache_pages(req); + return 0; + case WRITE: + if (!tr->writesect) + return -EIO; + + rq_flush_dcache_pages(req); + for (; nsect > 0; nsect--, block++, buf += tr->blksize) + if (tr->writesect(dev, block, buf)) + return -EIO; + return 0; + default: + printk(KERN_NOTICE "Unknown request %u\n", rq_data_dir(req)); + return -EIO; + } +} + +int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev) +{ + return dev->bg_stop; +} +EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background); + +static void mtd_blktrans_work(struct work_struct *work) +{ + struct mtd_blktrans_dev *dev = + container_of(work, struct mtd_blktrans_dev, work); + struct mtd_blktrans_ops *tr = dev->tr; + struct request_queue *rq = dev->rq; + struct request *req = NULL; + int background_done = 0; + + spin_lock_irq(rq->queue_lock); + + while (1) { + int res; + + dev->bg_stop = false; + if (!req && !(req = blk_fetch_request(rq))) { + if (tr->background && !background_done) { + spin_unlock_irq(rq->queue_lock); + mutex_lock(&dev->lock); + tr->background(dev); + mutex_unlock(&dev->lock); + spin_lock_irq(rq->queue_lock); + /* + * Do background processing just once per idle + * period. + */ + background_done = !dev->bg_stop; + continue; + } + break; + } + + spin_unlock_irq(rq->queue_lock); + + mutex_lock(&dev->lock); + res = do_blktrans_request(dev->tr, dev, req); + mutex_unlock(&dev->lock); + + spin_lock_irq(rq->queue_lock); + + if (!__blk_end_request_cur(req, res)) + req = NULL; + + background_done = 0; + } + + spin_unlock_irq(rq->queue_lock); +} + +static void mtd_blktrans_request(struct request_queue *rq) +{ + struct mtd_blktrans_dev *dev; + struct request *req = NULL; + + dev = rq->queuedata; + + if (!dev) + while ((req = blk_fetch_request(rq)) != NULL) + __blk_end_request_all(req, -ENODEV); + else + queue_work(dev->wq, &dev->work); +} + +static int blktrans_open(struct block_device *bdev, fmode_t mode) +{ + struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); + int ret = 0; + + if (!dev) + return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/ + + mutex_lock(&dev->lock); + mutex_lock(&mtd_table_mutex); + + if (dev->open) + goto unlock; + + kref_get(&dev->ref); + __module_get(dev->tr->owner); + + if (!dev->mtd) + goto unlock; + + if (dev->tr->open) { + ret = dev->tr->open(dev); + if (ret) + goto error_put; + } + + ret = __get_mtd_device(dev->mtd); + if (ret) + goto error_release; + dev->file_mode = mode; + +unlock: + dev->open++; + mutex_unlock(&mtd_table_mutex); + mutex_unlock(&dev->lock); + blktrans_dev_put(dev); + return ret; + +error_release: + if (dev->tr->release) + dev->tr->release(dev); +error_put: + module_put(dev->tr->owner); + kref_put(&dev->ref, blktrans_dev_release); + mutex_unlock(&mtd_table_mutex); + mutex_unlock(&dev->lock); + blktrans_dev_put(dev); + return ret; +} + +static void blktrans_release(struct gendisk *disk, fmode_t mode) +{ + struct mtd_blktrans_dev *dev = blktrans_dev_get(disk); + + if (!dev) + return; + + mutex_lock(&dev->lock); + mutex_lock(&mtd_table_mutex); + + if (--dev->open) + goto unlock; + + kref_put(&dev->ref, blktrans_dev_release); + module_put(dev->tr->owner); + + if (dev->mtd) { + if (dev->tr->release) + dev->tr->release(dev); + __put_mtd_device(dev->mtd); + } +unlock: + mutex_unlock(&mtd_table_mutex); + mutex_unlock(&dev->lock); + blktrans_dev_put(dev); +} + +static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo) +{ + struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); + int ret = -ENXIO; + + if (!dev) + return ret; + + mutex_lock(&dev->lock); + + if (!dev->mtd) + goto unlock; + + ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : 0; +unlock: + mutex_unlock(&dev->lock); + blktrans_dev_put(dev); + return ret; +} + +static int blktrans_ioctl(struct block_device *bdev, fmode_t mode, + unsigned int cmd, unsigned long arg) +{ + struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk); + int ret = -ENXIO; + + if (!dev) + return ret; + + mutex_lock(&dev->lock); + + if (!dev->mtd) + goto unlock; + + switch (cmd) { + case BLKFLSBUF: + ret = dev->tr->flush ? dev->tr->flush(dev) : 0; + break; + default: + ret = -ENOTTY; + } +unlock: + mutex_unlock(&dev->lock); + blktrans_dev_put(dev); + return ret; +} + +static const struct block_device_operations mtd_block_ops = { + .owner = THIS_MODULE, + .open = blktrans_open, + .release = blktrans_release, + .ioctl = blktrans_ioctl, + .getgeo = blktrans_getgeo, +}; + +int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new) +{ + struct mtd_blktrans_ops *tr = new->tr; + struct mtd_blktrans_dev *d; + int last_devnum = -1; + struct gendisk *gd; + int ret; + + if (mutex_trylock(&mtd_table_mutex)) { + mutex_unlock(&mtd_table_mutex); + BUG(); + } + + mutex_lock(&blktrans_ref_mutex); + list_for_each_entry(d, &tr->devs, list) { + if (new->devnum == -1) { + /* Use first free number */ + if (d->devnum != last_devnum+1) { + /* Found a free devnum. Plug it in here */ + new->devnum = last_devnum+1; + list_add_tail(&new->list, &d->list); + goto added; + } + } else if (d->devnum == new->devnum) { + /* Required number taken */ + mutex_unlock(&blktrans_ref_mutex); + return -EBUSY; + } else if (d->devnum > new->devnum) { + /* Required number was free */ + list_add_tail(&new->list, &d->list); + goto added; + } + last_devnum = d->devnum; + } + + ret = -EBUSY; + if (new->devnum == -1) + new->devnum = last_devnum+1; + + /* Check that the device and any partitions will get valid + * minor numbers and that the disk naming code below can cope + * with this number. */ + if (new->devnum > (MINORMASK >> tr->part_bits) || + (tr->part_bits && new->devnum >= 27 * 26)) { + mutex_unlock(&blktrans_ref_mutex); + goto error1; + } + + list_add_tail(&new->list, &tr->devs); + added: + mutex_unlock(&blktrans_ref_mutex); + + mutex_init(&new->lock); + kref_init(&new->ref); + if (!tr->writesect) + new->readonly = 1; + + /* Create gendisk */ + ret = -ENOMEM; + gd = alloc_disk(1 << tr->part_bits); + + if (!gd) + goto error2; + + new->disk = gd; + gd->private_data = new; + gd->major = tr->major; + gd->first_minor = (new->devnum) << tr->part_bits; + gd->fops = &mtd_block_ops; + + if (tr->part_bits) + if (new->devnum < 26) + snprintf(gd->disk_name, sizeof(gd->disk_name), + "%s%c", tr->name, 'a' + new->devnum); + else + snprintf(gd->disk_name, sizeof(gd->disk_name), + "%s%c%c", tr->name, + 'a' - 1 + new->devnum / 26, + 'a' + new->devnum % 26); + else + snprintf(gd->disk_name, sizeof(gd->disk_name), + "%s%d", tr->name, new->devnum); + + set_capacity(gd, (new->size * tr->blksize) >> 9); + + /* Create the request queue */ + spin_lock_init(&new->queue_lock); + new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock); + + if (!new->rq) + goto error3; + + if (tr->flush) + blk_queue_flush(new->rq, REQ_FLUSH); + + new->rq->queuedata = new; + blk_queue_logical_block_size(new->rq, tr->blksize); + + queue_flag_set_unlocked(QUEUE_FLAG_NONROT, new->rq); + queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, new->rq); + + if (tr->discard) { + queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, new->rq); + new->rq->limits.max_discard_sectors = UINT_MAX; + } + + gd->queue = new->rq; + + /* Create processing workqueue */ + new->wq = alloc_workqueue("%s%d", 0, 0, + tr->name, new->mtd->index); + if (!new->wq) + goto error4; + INIT_WORK(&new->work, mtd_blktrans_work); + + gd->driverfs_dev = &new->mtd->dev; + + if (new->readonly) + set_disk_ro(gd, 1); + + add_disk(gd); + + if (new->disk_attributes) { + ret = sysfs_create_group(&disk_to_dev(gd)->kobj, + new->disk_attributes); + WARN_ON(ret); + } + return 0; +error4: + blk_cleanup_queue(new->rq); +error3: + put_disk(new->disk); +error2: + list_del(&new->list); +error1: + return ret; +} + +int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old) +{ + unsigned long flags; + + if (mutex_trylock(&mtd_table_mutex)) { + mutex_unlock(&mtd_table_mutex); + BUG(); + } + + if (old->disk_attributes) + sysfs_remove_group(&disk_to_dev(old->disk)->kobj, + old->disk_attributes); + + /* Stop new requests to arrive */ + del_gendisk(old->disk); + + /* Stop workqueue. This will perform any pending request. */ + destroy_workqueue(old->wq); + + /* Kill current requests */ + spin_lock_irqsave(&old->queue_lock, flags); + old->rq->queuedata = NULL; + blk_start_queue(old->rq); + spin_unlock_irqrestore(&old->queue_lock, flags); + + /* If the device is currently open, tell trans driver to close it, + then put mtd device, and don't touch it again */ + mutex_lock(&old->lock); + if (old->open) { + if (old->tr->release) + old->tr->release(old); + __put_mtd_device(old->mtd); + } + + old->mtd = NULL; + + mutex_unlock(&old->lock); + blktrans_dev_put(old); + return 0; +} + +static void blktrans_notify_remove(struct mtd_info *mtd) +{ + struct mtd_blktrans_ops *tr; + struct mtd_blktrans_dev *dev, *next; + + list_for_each_entry(tr, &blktrans_majors, list) + list_for_each_entry_safe(dev, next, &tr->devs, list) + if (dev->mtd == mtd) + tr->remove_dev(dev); +} + +static void blktrans_notify_add(struct mtd_info *mtd) +{ + struct mtd_blktrans_ops *tr; + + if (mtd->type == MTD_ABSENT) + return; + + list_for_each_entry(tr, &blktrans_majors, list) + tr->add_mtd(tr, mtd); +} + +static struct mtd_notifier blktrans_notifier = { + .add = blktrans_notify_add, + .remove = blktrans_notify_remove, +}; + +int register_mtd_blktrans(struct mtd_blktrans_ops *tr) +{ + struct mtd_info *mtd; + int ret; + + /* Register the notifier if/when the first device type is + registered, to prevent the link/init ordering from fucking + us over. */ + if (!blktrans_notifier.list.next) + register_mtd_user(&blktrans_notifier); + + + mutex_lock(&mtd_table_mutex); + + ret = register_blkdev(tr->major, tr->name); + if (ret < 0) { + printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n", + tr->name, tr->major, ret); + mutex_unlock(&mtd_table_mutex); + return ret; + } + + if (ret) + tr->major = ret; + + tr->blkshift = ffs(tr->blksize) - 1; + + INIT_LIST_HEAD(&tr->devs); + list_add(&tr->list, &blktrans_majors); + + mtd_for_each_device(mtd) + if (mtd->type != MTD_ABSENT) + tr->add_mtd(tr, mtd); + + mutex_unlock(&mtd_table_mutex); + return 0; +} + +int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr) +{ + struct mtd_blktrans_dev *dev, *next; + + mutex_lock(&mtd_table_mutex); + + /* Remove it from the list of active majors */ + list_del(&tr->list); + + list_for_each_entry_safe(dev, next, &tr->devs, list) + tr->remove_dev(dev); + + unregister_blkdev(tr->major, tr->name); + mutex_unlock(&mtd_table_mutex); + + BUG_ON(!list_empty(&tr->devs)); + return 0; +} + +static void __exit mtd_blktrans_exit(void) +{ + /* No race here -- if someone's currently in register_mtd_blktrans + we're screwed anyway. */ + if (blktrans_notifier.list.next) + unregister_mtd_user(&blktrans_notifier); +} + +module_exit(mtd_blktrans_exit); + +EXPORT_SYMBOL_GPL(register_mtd_blktrans); +EXPORT_SYMBOL_GPL(deregister_mtd_blktrans); +EXPORT_SYMBOL_GPL(add_mtd_blktrans_dev); +EXPORT_SYMBOL_GPL(del_mtd_blktrans_dev); + +MODULE_AUTHOR("David Woodhouse "); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Common interface to block layer for MTD 'translation layers'"); -- cgit v1.2.3