diff options
Diffstat (limited to 'ANDROID_3.4.5/drivers/mtd/mtdblock.c')
-rw-r--r-- | ANDROID_3.4.5/drivers/mtd/mtdblock.c | 407 |
1 files changed, 0 insertions, 407 deletions
diff --git a/ANDROID_3.4.5/drivers/mtd/mtdblock.c b/ANDROID_3.4.5/drivers/mtd/mtdblock.c deleted file mode 100644 index 6c6d8073..00000000 --- a/ANDROID_3.4.5/drivers/mtd/mtdblock.c +++ /dev/null @@ -1,407 +0,0 @@ -/* - * Direct MTD block device access - * - * Copyright © 1999-2010 David Woodhouse <dwmw2@infradead.org> - * Copyright © 2000-2003 Nicolas Pitre <nico@fluxnic.net> - * - * 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 <linux/fs.h> -#include <linux/init.h> -#include <linux/kernel.h> -#include <linux/module.h> -#include <linux/sched.h> -#include <linux/slab.h> -#include <linux/types.h> -#include <linux/vmalloc.h> - -#include <linux/mtd/mtd.h> -#include <linux/mtd/blktrans.h> -#include <linux/mutex.h> - - -struct mtdblk_dev { - struct mtd_blktrans_dev mbd; - int count; - struct mutex cache_mutex; - unsigned char *cache_data; - unsigned long cache_offset; - unsigned int cache_size; - enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state; -}; - -static DEFINE_MUTEX(mtdblks_lock); - -/* - * Cache stuff... - * - * Since typical flash erasable sectors are much larger than what Linux's - * buffer cache can handle, we must implement read-modify-write on flash - * sectors for each block write requests. To avoid over-erasing flash sectors - * and to speed things up, we locally cache a whole flash sector while it is - * being written to until a different sector is required. - */ - -static void erase_callback(struct erase_info *done) -{ - wait_queue_head_t *wait_q = (wait_queue_head_t *)done->priv; - wake_up(wait_q); -} - -static int erase_write (struct mtd_info *mtd, unsigned long pos, - int len, const char *buf) -{ - struct erase_info erase; - DECLARE_WAITQUEUE(wait, current); - wait_queue_head_t wait_q; - size_t retlen; - int ret; - - /* - * First, let's erase the flash block. - */ - - init_waitqueue_head(&wait_q); - erase.mtd = mtd; - erase.callback = erase_callback; - erase.addr = pos; - erase.len = len; - erase.priv = (u_long)&wait_q; - - set_current_state(TASK_INTERRUPTIBLE); - add_wait_queue(&wait_q, &wait); - - ret = mtd_erase(mtd, &erase); - if (ret) { - set_current_state(TASK_RUNNING); - remove_wait_queue(&wait_q, &wait); - printk (KERN_WARNING "mtdblock: erase of region [0x%lx, 0x%x] " - "on \"%s\" failed\n", - pos, len, mtd->name); - return ret; - } - - schedule(); /* Wait for erase to finish. */ - remove_wait_queue(&wait_q, &wait); - - /* - * Next, write the data to flash. - */ - - ret = mtd_write(mtd, pos, len, &retlen, buf); - if (ret) - return ret; - if (retlen != len) - return -EIO; - return 0; -} - - -static int write_cached_data (struct mtdblk_dev *mtdblk) -{ - struct mtd_info *mtd = mtdblk->mbd.mtd; - int ret; - - if (mtdblk->cache_state != STATE_DIRTY) - return 0; - - pr_debug("mtdblock: writing cached data for \"%s\" " - "at 0x%lx, size 0x%x\n", mtd->name, - mtdblk->cache_offset, mtdblk->cache_size); - - ret = erase_write (mtd, mtdblk->cache_offset, - mtdblk->cache_size, mtdblk->cache_data); - if (ret) - return ret; - - /* - * Here we could arguably set the cache state to STATE_CLEAN. - * However this could lead to inconsistency since we will not - * be notified if this content is altered on the flash by other - * means. Let's declare it empty and leave buffering tasks to - * the buffer cache instead. - */ - mtdblk->cache_state = STATE_EMPTY; - return 0; -} - - -static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos, - int len, const char *buf) -{ - struct mtd_info *mtd = mtdblk->mbd.mtd; - unsigned int sect_size = mtdblk->cache_size; - size_t retlen; - int ret; - - pr_debug("mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n", - mtd->name, pos, len); - - if (!sect_size) - return mtd_write(mtd, pos, len, &retlen, buf); - - while (len > 0) { - unsigned long sect_start = (pos/sect_size)*sect_size; - unsigned int offset = pos - sect_start; - unsigned int size = sect_size - offset; - if( size > len ) - size = len; - - if (size == sect_size) { - /* - * We are covering a whole sector. Thus there is no - * need to bother with the cache while it may still be - * useful for other partial writes. - */ - ret = erase_write (mtd, pos, size, buf); - if (ret) - return ret; - } else { - /* Partial sector: need to use the cache */ - - if (mtdblk->cache_state == STATE_DIRTY && - mtdblk->cache_offset != sect_start) { - ret = write_cached_data(mtdblk); - if (ret) - return ret; - } - - if (mtdblk->cache_state == STATE_EMPTY || - mtdblk->cache_offset != sect_start) { - /* fill the cache with the current sector */ - mtdblk->cache_state = STATE_EMPTY; - ret = mtd_read(mtd, sect_start, sect_size, - &retlen, mtdblk->cache_data); - if (ret) - return ret; - if (retlen != sect_size) - return -EIO; - - mtdblk->cache_offset = sect_start; - mtdblk->cache_size = sect_size; - mtdblk->cache_state = STATE_CLEAN; - } - - /* write data to our local cache */ - memcpy (mtdblk->cache_data + offset, buf, size); - mtdblk->cache_state = STATE_DIRTY; - } - - buf += size; - pos += size; - len -= size; - } - - return 0; -} - - -static int do_cached_read (struct mtdblk_dev *mtdblk, unsigned long pos, - int len, char *buf) -{ - struct mtd_info *mtd = mtdblk->mbd.mtd; - unsigned int sect_size = mtdblk->cache_size; - size_t retlen; - int ret; - - pr_debug("mtdblock: read on \"%s\" at 0x%lx, size 0x%x\n", - mtd->name, pos, len); - - if (!sect_size) - return mtd_read(mtd, pos, len, &retlen, buf); - - while (len > 0) { - unsigned long sect_start = (pos/sect_size)*sect_size; - unsigned int offset = pos - sect_start; - unsigned int size = sect_size - offset; - if (size > len) - size = len; - - /* - * Check if the requested data is already cached - * Read the requested amount of data from our internal cache if it - * contains what we want, otherwise we read the data directly - * from flash. - */ - if (mtdblk->cache_state != STATE_EMPTY && - mtdblk->cache_offset == sect_start) { - memcpy (buf, mtdblk->cache_data + offset, size); - } else { - ret = mtd_read(mtd, pos, size, &retlen, buf); - if (ret) - return ret; - if (retlen != size) - return -EIO; - } - - buf += size; - pos += size; - len -= size; - } - - return 0; -} - -static int mtdblock_readsect(struct mtd_blktrans_dev *dev, - unsigned long block, char *buf) -{ - struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd); - return do_cached_read(mtdblk, block<<9, 512, buf); -} - -static int mtdblock_writesect(struct mtd_blktrans_dev *dev, - unsigned long block, char *buf) -{ - struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd); - if (unlikely(!mtdblk->cache_data && mtdblk->cache_size)) { - mtdblk->cache_data = vmalloc(mtdblk->mbd.mtd->erasesize); - if (!mtdblk->cache_data) - return -EINTR; - /* -EINTR is not really correct, but it is the best match - * documented in man 2 write for all cases. We could also - * return -EAGAIN sometimes, but why bother? - */ - } - return do_cached_write(mtdblk, block<<9, 512, buf); -} - -static int mtdblock_open(struct mtd_blktrans_dev *mbd) -{ - struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd); - - pr_debug("mtdblock_open\n"); - - mutex_lock(&mtdblks_lock); - if (mtdblk->count) { - mtdblk->count++; - mutex_unlock(&mtdblks_lock); - return 0; - } - - /* OK, it's not open. Create cache info for it */ - mtdblk->count = 1; - mutex_init(&mtdblk->cache_mutex); - mtdblk->cache_state = STATE_EMPTY; - if (!(mbd->mtd->flags & MTD_NO_ERASE) && mbd->mtd->erasesize) { - mtdblk->cache_size = mbd->mtd->erasesize; - mtdblk->cache_data = NULL; - } - - mutex_unlock(&mtdblks_lock); - - pr_debug("ok\n"); - - return 0; -} - -static int mtdblock_release(struct mtd_blktrans_dev *mbd) -{ - struct mtdblk_dev *mtdblk = container_of(mbd, struct mtdblk_dev, mbd); - - pr_debug("mtdblock_release\n"); - - mutex_lock(&mtdblks_lock); - - mutex_lock(&mtdblk->cache_mutex); - write_cached_data(mtdblk); - mutex_unlock(&mtdblk->cache_mutex); - - if (!--mtdblk->count) { - /* - * It was the last usage. Free the cache, but only sync if - * opened for writing. - */ - if (mbd->file_mode & FMODE_WRITE) - mtd_sync(mbd->mtd); - vfree(mtdblk->cache_data); - } - - mutex_unlock(&mtdblks_lock); - - pr_debug("ok\n"); - - return 0; -} - -static int mtdblock_flush(struct mtd_blktrans_dev *dev) -{ - struct mtdblk_dev *mtdblk = container_of(dev, struct mtdblk_dev, mbd); - - mutex_lock(&mtdblk->cache_mutex); - write_cached_data(mtdblk); - mutex_unlock(&mtdblk->cache_mutex); - mtd_sync(dev->mtd); - return 0; -} - -static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) -{ - struct mtdblk_dev *dev = kzalloc(sizeof(*dev), GFP_KERNEL); - - if (!dev) - return; - - dev->mbd.mtd = mtd; - dev->mbd.devnum = mtd->index; - - dev->mbd.size = mtd->size >> 9; - dev->mbd.tr = tr; - - if (!(mtd->flags & MTD_WRITEABLE)) - dev->mbd.readonly = 1; - - if (add_mtd_blktrans_dev(&dev->mbd)) - kfree(dev); -} - -static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev) -{ - del_mtd_blktrans_dev(dev); -} - -static struct mtd_blktrans_ops mtdblock_tr = { - .name = "mtdblock", - .major = 31, - .part_bits = 0, - .blksize = 512, - .open = mtdblock_open, - .flush = mtdblock_flush, - .release = mtdblock_release, - .readsect = mtdblock_readsect, - .writesect = mtdblock_writesect, - .add_mtd = mtdblock_add_mtd, - .remove_dev = mtdblock_remove_dev, - .owner = THIS_MODULE, -}; - -static int __init init_mtdblock(void) -{ - return register_mtd_blktrans(&mtdblock_tr); -} - -static void __exit cleanup_mtdblock(void) -{ - deregister_mtd_blktrans(&mtdblock_tr); -} - -module_init(init_mtdblock); -module_exit(cleanup_mtdblock); - - -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Nicolas Pitre <nico@fluxnic.net> et al."); -MODULE_DESCRIPTION("Caching read/erase/writeback block device emulation access to MTD devices"); |