/* * $Id: blkmtd.c,v 1.3 2001/10/02 15:33:20 dwmw2 Exp $ * blkmtd.c - use a block device as a fake MTD * * Author: Simon Evans * * Copyright (C) 2001 Simon Evans * * Licence: GPL * * How it works: * The driver uses raw/io to read/write the device and the page * cache to cache access. Writes update the page cache with the * new data but make a copy of the new page(s) and then a kernel * thread writes pages out to the device in the background. This * ensures tht writes are order even if a page is updated twice. * Also, since pages in the page cache are never marked as dirty, * we dont have to worry about writepage() being called on some * random page which may not be in the write order. * * Erases are handled like writes, so the callback is called after * the page cache has been updated. Sync()ing will wait until it is * all done. * * It can be loaded Read-Only to prevent erases and writes to the * medium. * * Todo: * Make the write queue size dynamic so this it is not too big on * small memory systems and too small on large memory systems. * * Page cache usage may still be a bit wrong. Check we are doing * everything proberly. * * Somehow allow writes to dirty the page cache so we dont use too * much memory making copies of outgoing pages. Need to handle case * where page x is written to, then page y, then page x again before * any of them have been committed to disk. * * Reading should read multiple pages at once rather than using * readpage() for each one. This is easy and will be fixed asap. * * Dont run the write_thread if readonly. This is also easy and will * be fixed asap. * * Even though the multiple erase regions are used if the default erase * block size doesnt match the device properly, erases currently wont * work on the last page if it is not a full page. */ #include #include #include #include #include #include #include #include #include /* Default erase size in K, always make it a multiple of PAGE_SIZE */ #define CONFIG_MTD_BLKDEV_ERASESIZE 128 #define VERSION "1.1" extern int *blk_size[]; extern int *blksize_size[]; /* Info for the block device */ typedef struct mtd_raw_dev_data_s { struct block_device *binding; int sector_size, sector_bits, total_sectors; size_t totalsize; int readonly; struct address_space as; struct file *file; } mtd_raw_dev_data_t; /* Info for each queue item in the write queue */ typedef struct mtdblkdev_write_queue_s { mtd_raw_dev_data_t *rawdevice; struct page **pages; int pagenr; int pagecnt; int iserase; } mtdblkdev_write_queue_t; /* Static info about the MTD, used in cleanup_module */ static struct mtd_info *mtd_info; /* Write queue fixed size */ #define WRITE_QUEUE_SZ 512 /* Storage for the write queue */ static mtdblkdev_write_queue_t write_queue[WRITE_QUEUE_SZ]; static int volatile write_queue_head; static int volatile write_queue_tail; static int volatile write_queue_cnt; static spinlock_t mbd_writeq_lock = SPIN_LOCK_UNLOCKED; /* Tell the write thread to finish */ static volatile int write_task_finish = 0; /* ipc with the write thread */ #if LINUX_VERSION_CODE > 0x020300 static DECLARE_MUTEX_LOCKED(thread_sem); static DECLARE_WAIT_QUEUE_HEAD(thr_wq); static DECLARE_WAIT_QUEUE_HEAD(mtbd_sync_wq); #else static struct semaphore thread_sem = MUTEX_LOCKED; DECLARE_WAIT_QUEUE_HEAD(thr_wq); DECLARE_WAIT_QUEUE_HEAD(mtbd_sync_wq); #endif /* Module parameters passed by insmod/modprobe */ char *device; /* the block device to use */ int erasesz; /* optional default erase size */ int ro; /* optional read only flag */ int bs; /* optionally force the block size (avoid using) */ int count; /* optionally force the block count (avoid using) */ #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0) MODULE_LICENSE("GPL"); MODULE_AUTHOR("Simon Evans "); MODULE_DESCRIPTION("Emulate an MTD using a block device"); MODULE_PARM(device, "s"); MODULE_PARM_DESC(device, "block device to use"); MODULE_PARM(erasesz, "i"); MODULE_PARM_DESC(erasesz, "optional erase size to use in KB. eg 4=4K."); MODULE_PARM(ro, "i"); MODULE_PARM_DESC(ro, "1=Read only, writes and erases cause errors"); MODULE_PARM(bs, "i"); MODULE_PARM_DESC(bs, "force the block size in bytes"); MODULE_PARM(count, "i"); MODULE_PARM_DESC(count, "force the block count"); #endif /* Page cache stuff */ /* writepage() - should never be called - catch it anyway */ static int blkmtd_writepage(struct page *page) { printk("blkmtd: writepage called!!!\n"); return -EIO; } /* readpage() - reads one page from the block device */ static int blkmtd_readpage(struct file *file, struct page *page) { int err; int sectornr, sectors, i; struct kiobuf *iobuf; mtd_raw_dev_data_t *rawdevice = (mtd_raw_dev_data_t *)file->private_data; kdev_t dev; if(!rawdevice) { printk("blkmtd: readpage: PANIC file->private_data == NULL\n"); return -EIO; } dev = to_kdev_t(rawdevice->binding->bd_dev); DEBUG(2, "blkmtd: readpage called, dev = `%s' page = %p index = %ld\n", bdevname(dev), page, page->index); if(Page_Uptodate(page)) { DEBUG(1, "blkmtd: readpage page %ld is already upto date\n", page->index); UnlockPage(page); return 0; } ClearPageUptodate(page); ClearPageError(page); /* see if page is in the outgoing write queue */ spin_lock(&mbd_writeq_lock); if(write_queue_cnt) { int i = write_queue_tail; while(i != write_queue_head) { mtdblkdev_write_queue_t *item = &write_queue[i]; if(page->index >= item->pagenr && page->index < item->pagenr+item->pagecnt) { /* yes it is */ int index = item->pagenr - page->index; DEBUG(1, "blkmtd: readpage: found page %ld in outgoing write queue\n", page->index); if(item->iserase) { memset(page_address(page), 0xff, PAGE_SIZE); } else { memcpy(page_address(page), page_address(item->pages[index]), PAGE_SIZE); } SetPageUptodate(page); flush_dcache_page(page); UnlockPage(page); spin_unlock(&mbd_writeq_lock); return 0; } i++; i %= WRITE_QUEUE_SZ; } } spin_unlock(&mbd_writeq_lock); DEBUG(3, "blkmtd: readpage: getting kiovec\n"); err = alloc_kiovec(1, &iobuf); if (err) { return err; } iobuf->offset = 0; iobuf->nr_pages = 1; iobuf->length = PAGE_SIZE; iobuf->locked = 1; iobuf->maplist[0] = page; sectornr = page->index << (PAGE_SHIFT - rawdevice->sector_bits); sectors = 1 << (PAGE_SHIFT - rawdevice->sector_bits); DEBUG(3, "blkmtd: readpage: sectornr = %d sectors = %d\n", sectornr, sectors); for(i = 0; i < sectors; i++) { iobuf->blocks[i] = sectornr++; } DEBUG(3, "bklmtd: readpage: starting brw_kiovec\n"); err = brw_kiovec(READ, 1, &iobuf, dev, iobuf->blocks, rawdevice->sector_size); DEBUG(3, "blkmtd: readpage: finished, err = %d\n", err); iobuf->locked = 0; free_kiovec(1, &iobuf); if(err != PAGE_SIZE) { printk("blkmtd: readpage: error reading page %ld\n", page->index); memset(page_address(page), 0, PAGE_SIZE); SetPageError(page); err = -EIO; } else { DEBUG(3, "blkmtd: readpage: setting page upto date\n"); SetPageUptodate(page); err = 0; } flush_dcache_page(page); UnlockPage(page); DEBUG(2, "blkmtd: readpage: finished, err = %d\n", err); return 0; } static struct address_space_operations blkmtd_aops = { writepage: blkmtd_writepage, readpage: blkmtd_readpage, }; /* This is the kernel thread that empties the write queue to disk */ static int write_queue_task(void *data) { int err; struct task_struct *tsk = current; struct kiobuf *iobuf; DECLARE_WAITQUEUE(wait, tsk); DEBUG(1, "blkmtd: writetask: starting (pid = %d)\n", tsk->pid); daemonize(); strcpy(tsk->comm, "blkmtdd"); tsk->tty = NULL; spin_lock_irq(&tsk->sigmask_lock); sigfillset(&tsk->blocked); recalc_sigpending(tsk); spin_unlock_irq(&tsk->sigmask_lock); exit_sighand(tsk); if(alloc_kiovec(1, &iobuf)) return 0; DEBUG(2, "blkmtd: writetask: entering main loop\n"); add_wait_queue(&thr_wq, &wait); while(1) { spin_lock(&mbd_writeq_lock); if(!write_queue_cnt) { /* If nothing in the queue, wake up anyone wanting to know when there is space in the queue then sleep for 2*HZ */ spin_unlock(&mbd_writeq_lock); DEBUG(3, "blkmtd: writetask: queue empty\n"); if(waitqueue_active(&mtbd_sync_wq)) wake_up(&mtbd_sync_wq); interruptible_sleep_on_timeout(&thr_wq, 2*HZ); DEBUG(3, "blkmtd: writetask: woken up\n"); if(write_task_finish) break; } else { /* we have stuff to write */ mtdblkdev_write_queue_t *item = &write_queue[write_queue_tail]; struct page **pages = item->pages; int pagecnt = item->pagecnt; int pagenr = item->pagenr; int i; int max_sectors = KIO_MAX_SECTORS >> (item->rawdevice->sector_bits - 9); kdev_t dev = to_kdev_t(item->rawdevice->binding->bd_dev); DEBUG(3, "blkmtd: writetask: got %d queue items\n", write_queue_cnt); set_current_state(TASK_RUNNING); spin_unlock(&mbd_writeq_lock); DEBUG(2, "blkmtd: write_task: writing pagenr = %d pagecnt = %d", item->pagenr, item->pagecnt); iobuf->offset = 0; iobuf->locked = 1; /* Loop through all the pages to be written in the queue item, remembering we can only write KIO_MAX_SECTORS at a time */ while(pagecnt) { int sectornr = pagenr << (PAGE_SHIFT - item->rawdevice->sector_bits); int sectorcnt = pagecnt << (PAGE_SHIFT - item->rawdevice->sector_bits); int cursectors = (sectorcnt < max_sectors) ? sectorcnt : max_sectors; int cpagecnt = (cursectors << item->rawdevice->sector_bits) + PAGE_SIZE-1; cpagecnt >>= PAGE_SHIFT; for(i = 0; i < cpagecnt; i++) iobuf->maplist[i] = *(pages++); for(i = 0; i < cursectors; i++) { iobuf->blocks[i] = sectornr++; } iobuf->nr_pages = cpagecnt; iobuf->length = cursectors << item->rawdevice->sector_bits; DEBUG(3, "blkmtd: write_task: about to kiovec\n"); err = brw_kiovec(WRITE, 1, &iobuf, dev, iobuf->blocks, item->rawdevice->sector_size); DEBUG(3, "bklmtd: write_task: done, err = %d\n", err); if(err != (cursectors << item->rawdevice->sector_bits)) { /* if an error occured - set this to exit the loop */ pagecnt = 0; } else { pagenr += cpagecnt; pagecnt -= cpagecnt; } } /* free up the pages used in the write and list of pages used in the write queue item */ iobuf->locked = 0; spin_lock(&mbd_writeq_lock); write_queue_cnt--; write_queue_tail++; write_queue_tail %= WRITE_QUEUE_SZ; for(i = 0 ; i < item->pagecnt; i++) { UnlockPage(item->pages[i]); __free_pages(item->pages[i], 0); } kfree(item->pages); item->pages = NULL; spin_unlock(&mbd_writeq_lock); /* Tell others there is some space in the write queue */ if(waitqueue_active(&mtbd_sync_wq)) wake_up(&mtbd_sync_wq); } } remove_wait_queue(&thr_wq, &wait); DEBUG(1, "blkmtd: writetask: exiting\n"); free_kiovec(1, &iobuf); /* Tell people we have exitd */ up(&thread_sem); return 0; } /* Add a range of pages into the outgoing write queue, making copies of them */ static int queue_page_write(mtd_raw_dev_data_t *rawdevice, struct page **pages, int pagenr, int pagecnt, int iserase) { struct page *outpage; struct page **new_pages; mtdblkdev_write_queue_t *item; int i; DECLARE_WAITQUEUE(wait, current); DEBUG(2, "mtdblkdev: queue_page_write: adding pagenr = %d pagecnt = %d\n", pagenr, pagecnt); if(!pagecnt) return 0; if(pages == NULL) return -EINVAL; /* create a array for the list of pages */ new_pages = kmalloc(pagecnt * sizeof(struct page *), GFP_KERNEL); if(new_pages == NULL) return -ENOMEM; /* make copies of the pages in the page cache */ for(i = 0; i < pagecnt; i++) { outpage = alloc_pages(GFP_KERNEL, 0); if(!outpage) { while(i--) { UnlockPage(new_pages[i]); __free_pages(new_pages[i], 0); } kfree(new_pages); return -ENOMEM; } lock_page(outpage); memcpy(page_address(outpage), page_address(pages[i]), PAGE_SIZE); new_pages[i] = outpage; } /* wait until there is some space in the write queue */ test_lock: spin_lock(&mbd_writeq_lock); if(write_queue_cnt == WRITE_QUEUE_SZ) { spin_unlock(&mbd_writeq_lock); DEBUG(3, "blkmtd: queue_page: Queue full\n"); current->state = TASK_UNINTERRUPTIBLE; add_wait_queue(&mtbd_sync_wq, &wait); wake_up_interruptible(&thr_wq); schedule(); current->state = TASK_RUNNING; remove_wait_queue(&mtbd_sync_wq, &wait); DEBUG(3, "blkmtd: queue_page: Queue has %d items in it\n", write_queue_cnt); goto test_lock; } DEBUG(3, "blkmtd: queue_write_page: qhead: %d qtail: %d qcnt: %d\n", write_queue_head, write_queue_tail, write_queue_cnt); /* fix up the queue item */ item = &write_queue[write_queue_head]; item->pages = new_pages; item->pagenr = pagenr; item->pagecnt = pagecnt; item->rawdevice = rawdevice; item->iserase = iserase; write_queue_head++; write_queue_head %= WRITE_QUEUE_SZ; write_queue_cnt++; DEBUG(3, "blkmtd: queue_write_page: qhead: %d qtail: %d qcnt: %d\n", write_queue_head, write_queue_tail, write_queue_cnt); spin_unlock(&mbd_writeq_lock); DEBUG(2, "blkmtd: queue_page_write: finished\n"); return 0; } /* erase a specified part of the device */ static int blkmtd_erase(struct mtd_info *mtd, struct erase_info *instr) { mtd_raw_dev_data_t *rawdevice = mtd->priv; size_t from; u_long len; int err = 0; /* check readonly */ if(rawdevice->readonly) { printk("blkmtd: error: trying to erase readonly device %s\n", device); instr->state = MTD_ERASE_FAILED; goto erase_callback; } instr->state = MTD_ERASING; from = instr->addr; len = instr->len; /* check page alignment of start and length */ DEBUG(2, "blkmtd: erase: dev = `%s' from = %d len = %ld\n", bdevname(rawdevice->binding->bd_dev), from, len); if(from % PAGE_SIZE) { printk("blkmtd: erase: addr not page aligned (addr = %d)\n", from); instr->state = MTD_ERASE_FAILED; err = -EIO; } if(len % PAGE_SIZE) { printk("blkmtd: erase: len not a whole number of pages (len = %ld)\n", len); instr->state = MTD_ERASE_FAILED; err = -EIO; } if(instr->state != MTD_ERASE_FAILED) { /* start the erase */ int pagenr, pagecnt; struct page *page, **pages; int i = 0; pagenr = from >> PAGE_SHIFT; pagecnt = len >> PAGE_SHIFT; DEBUG(3, "blkmtd: erase: pagenr = %d pagecnt = %d\n", pagenr, pagecnt); pages = kmalloc(pagecnt * sizeof(struct page *), GFP_KERNEL); if(pages == NULL) { err = -ENOMEM; instr->state = MTD_ERASE_FAILED; goto erase_out; } while(pagecnt) { /* get the page via the page cache */ DEBUG(3, "blkmtd: erase: doing grap_cache_page() for page %d\n", pagenr); page = grab_cache_page(&rawdevice->as, pagenr); if(!page) { DEBUG(3, "blkmtd: erase: grab_cache_page() failed for page %d\n", pagenr); kfree(pages); err = -EIO; instr->state = MTD_ERASE_FAILED; goto erase_out; } memset(page_address(page), 0xff, PAGE_SIZE); pages[i] = page; pagecnt--; pagenr++; i++; } DEBUG(3, "blkmtd: erase: queuing page write\n"); err = queue_page_write(rawdevice, pages, from >> PAGE_SHIFT, len >> PAGE_SHIFT, 1); pagecnt = len >> PAGE_SHIFT; if(!err) { while(pagecnt--) { SetPageUptodate(pages[pagecnt]); UnlockPage(pages[pagecnt]); page_cache_release(pages[pagecnt]); flush_dcache_page(pages[pagecnt]); } kfree(pages); instr->state = MTD_ERASE_DONE; } else { while(pagecnt--) { SetPageError(pages[pagecnt]); page_cache_release(pages[pagecnt]); } kfree(pages); instr->state = MTD_ERASE_FAILED; } } erase_out: DEBUG(3, "blkmtd: erase: checking callback\n"); erase_callback: if (instr->callback) { (*(instr->callback))(instr); } DEBUG(2, "blkmtd: erase: finished (err = %d)\n", err); return err; } /* read a range of the data via the page cache */ static int blkmtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) { mtd_raw_dev_data_t *rawdevice = mtd->priv; int err = 0; int offset; int pagenr, pages; *retlen = 0; DEBUG(2, "blkmtd: read: dev = `%s' from = %ld len = %d buf = %p\n", bdevname(rawdevice->binding->bd_dev), (long int)from, len, buf); pagenr = from >> PAGE_SHIFT; offset = from - (pagenr << PAGE_SHIFT); pages = (offset+len+PAGE_SIZE-1) >> PAGE_SHIFT; DEBUG(3, "blkmtd: read: pagenr = %d offset = %d, pages = %d\n", pagenr, offset, pages); /* just loop through each page, getting it via readpage() - slow but easy */ while(pages) { struct page *page; int cpylen; DEBUG(3, "blkmtd: read: looking for page: %d\n", pagenr); page = read_cache_page(&rawdevice->as, pagenr, (filler_t *)blkmtd_readpage, rawdevice->file); if(IS_ERR(page)) { return PTR_ERR(page); } wait_on_page(page); if(!Page_Uptodate(page)) { /* error reading page */ printk("blkmtd: read: page not uptodate\n"); page_cache_release(page); return -EIO; } cpylen = (PAGE_SIZE > len) ? len : PAGE_SIZE; if(offset+cpylen > PAGE_SIZE) cpylen = PAGE_SIZE-offset; memcpy(buf + *retlen, page_address(page) + offset, cpylen); offset = 0; len -= cpylen; *retlen += cpylen; pagenr++; pages--; page_cache_release(page); } DEBUG(2, "blkmtd: end read: retlen = %d, err = %d\n", *retlen, err); return err; } /* write a range of the data via the page cache. * * Basic operation. break the write into three parts. * * 1. From a page unaligned start up until the next page boundary * 2. Page sized, page aligned blocks * 3. From end of last aligned block to end of range * * 1,3 are read via the page cache and readpage() since these are partial * pages, 2 we just grab pages from the page cache, not caring if they are * already in memory or not since they will be completly overwritten. * */ static int blkmtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf) { mtd_raw_dev_data_t *rawdevice = mtd->priv; int err = 0; int offset; int pagenr; size_t len1 = 0, len2 = 0, len3 = 0; struct page **pages; int pagecnt = 0; *retlen = 0; DEBUG(2, "blkmtd: write: dev = `%s' to = %ld len = %d buf = %p\n", bdevname(rawdevice->binding->bd_dev), (long int)to, len, buf); /* handle readonly and out of range numbers */ if(rawdevice->readonly) { printk("blkmtd: error: trying to write to a readonly device %s\n", device); return -EROFS; } if(to >= rawdevice->totalsize) { return -ENOSPC; } if(to + len > rawdevice->totalsize) { len = (rawdevice->totalsize - to); } pagenr = to >> PAGE_SHIFT; offset = to - (pagenr << PAGE_SHIFT); /* see if we have to do a partial write at the start */ if(offset) { if((offset + len) > PAGE_SIZE) { len1 = PAGE_SIZE - offset; len -= len1; } else { len1 = len; len = 0; } } /* calculate the length of the other two regions */ len3 = len & ~PAGE_MASK; len -= len3; len2 = len; if(len1) pagecnt++; if(len2) pagecnt += len2 >> PAGE_SHIFT; if(len3) pagecnt++; DEBUG(3, "blkmtd: write: len1 = %d len2 = %d len3 = %d pagecnt = %d\n", len1, len2, len3, pagecnt); /* get space for list of pages */ pages = kmalloc(pagecnt * sizeof(struct page *), GFP_KERNEL); if(pages == NULL) { return -ENOMEM; } pagecnt = 0; if(len1) { /* do partial start region */ struct page *page; DEBUG(3, "blkmtd: write: doing partial start, page = %d len = %d offset = %d\n", pagenr, len1, offset); page = read_cache_page(&rawdevice->as, pagenr, (filler_t *)blkmtd_readpage, rawdevice->file); if(IS_ERR(page)) { kfree(pages); return PTR_ERR(page); } memcpy(page_address(page)+offset, buf, len1); pages[pagecnt++] = page; buf += len1; *retlen = len1; err = 0; pagenr++; } /* Now do the main loop to a page aligned, n page sized output */ if(len2) { int pagesc = len2 >> PAGE_SHIFT; DEBUG(3, "blkmtd: write: whole pages start = %d, count = %d\n", pagenr, pagesc); while(pagesc) { struct page *page; /* see if page is in the page cache */ DEBUG(3, "blkmtd: write: grabbing page %d from page cache\n", pagenr); page = grab_cache_page(&rawdevice->as, pagenr); DEBUG(3, "blkmtd: write: got page %d from page cache\n", pagenr); if(!page) { printk("blkmtd: write: cant grab cache page %d\n", pagenr); err = -EIO; goto write_err; } memcpy(page_address(page), buf, PAGE_SIZE); pages[pagecnt++] = page; UnlockPage(page); pagenr++; pagesc--; buf += PAGE_SIZE; *retlen += PAGE_SIZE; } } if(len3) { /* do the third region */ struct page *page; DEBUG(3, "blkmtd: write: doing partial end, page = %d len = %d\n", pagenr, len3); page = read_cache_page(&rawdevice->as, pagenr, (filler_t *)blkmtd_readpage, rawdevice->file); if(IS_ERR(page)) { err = PTR_ERR(page); goto write_err; } memcpy(page_address(page), buf, len3); DEBUG(3, "blkmtd: write: writing out partial end\n"); pages[pagecnt++] = page; *retlen += len3; err = 0; } DEBUG(2, "blkmtd: write: end, retlen = %d, err = %d\n", *retlen, err); /* submit it to the write task */ err = queue_page_write(rawdevice, pages, to >> PAGE_SHIFT, pagecnt, 0); if(!err) { while(pagecnt--) { SetPageUptodate(pages[pagecnt]); flush_dcache_page(pages[pagecnt]); page_cache_release(pages[pagecnt]); } kfree(pages); return 0; } write_err: while(--pagecnt) { SetPageError(pages[pagecnt]); page_cache_release(pages[pagecnt]); } kfree(pages); return err; } /* sync the device - wait until the write queue is empty */ static void blkmtd_sync(struct mtd_info *mtd) { DECLARE_WAITQUEUE(wait, current); DEBUG(2, "blkmtd: sync: called\n"); stuff_inq: spin_lock(&mbd_writeq_lock); if(write_queue_cnt) { spin_unlock(&mbd_writeq_lock); current->state = TASK_UNINTERRUPTIBLE; add_wait_queue(&mtbd_sync_wq, &wait); DEBUG(3, "blkmtd: sync: waking up task\n"); wake_up_interruptible(&thr_wq); schedule(); current->state = TASK_RUNNING; remove_wait_queue(&mtbd_sync_wq, &wait); DEBUG(3, "blkmtd: sync: waking up after write task\n"); goto stuff_inq; } spin_unlock(&mbd_writeq_lock); DEBUG(2, "blkmtdL sync: finished\n"); } /* Cleanup and exit - sync the device and kill of the kernel thread */ static void __exit cleanup_blkmtd(void) { if (mtd_info) { mtd_raw_dev_data_t *rawdevice = mtd_info->priv; // sync the device if (rawdevice) { blkmtd_sync(mtd_info); write_task_finish = 1; wake_up_interruptible(&thr_wq); down(&thread_sem); if(rawdevice->binding != NULL) blkdev_put(rawdevice->binding, BDEV_RAW); filp_close(rawdevice->file, NULL); kfree(mtd_info->priv); } if(mtd_info->eraseregions) kfree(mtd_info->eraseregions); del_mtd_device(mtd_info); kfree(mtd_info); mtd_info = NULL; } printk("blkmtd: unloaded for %s\n", device); } extern struct module __this_module; /* for a given size and initial erase size, calculate the number and size of each erase region */ static int __init calc_erase_regions(struct mtd_erase_region_info *info, size_t erase_size, size_t total_size) { int count = 0; int offset = 0; int regions = 0; while(total_size) { count = total_size / erase_size; if(count) { total_size = total_size % erase_size; if(info) { info->offset = offset; info->erasesize = erase_size; info->numblocks = count; info++; } offset += (count * erase_size); regions++; } while(erase_size > total_size) erase_size >>= 1; } return regions; } /* Startup */ static int __init init_blkmtd(void) { struct file *file = NULL; struct inode *inode; mtd_raw_dev_data_t *rawdevice = NULL; int maj, min; int i, blocksize, blocksize_bits; loff_t size = 0; int readonly = 0; int erase_size = CONFIG_MTD_BLKDEV_ERASESIZE; kdev_t rdev; int err; int mode; int totalsize = 0, total_sectors = 0; int regions; mtd_info = NULL; // Check args if(device == 0) { printk("blkmtd: error, missing `device' name\n"); return 1; } if(ro) readonly = 1; if(erasesz) erase_size = erasesz; DEBUG(1, "blkmtd: got device = `%s' erase size = %dK readonly = %s\n", device, erase_size, readonly ? "yes" : "no"); // Get a handle on the device mode = (readonly) ? O_RDONLY : O_RDWR; file = filp_open(device, mode, 0); if(IS_ERR(file)) { DEBUG(2, "blkmtd: open_namei returned %ld\n", PTR_ERR(file)); return 1; } /* determine is this is a block device and if so get its major and minor numbers */ inode = file->f_dentry->d_inode; if(!S_ISBLK(inode->i_mode)) { printk("blkmtd: %s not a block device\n", device); filp_close(file, NULL); return 1; } rdev = inode->i_rdev; //filp_close(file, NULL); DEBUG(1, "blkmtd: found a block device major = %d, minor = %d\n", MAJOR(rdev), MINOR(rdev)); maj = MAJOR(rdev); min = MINOR(rdev); if(maj == MTD_BLOCK_MAJOR) { printk("blkmtd: attempting to use an MTD device as a block device\n"); return 1; } DEBUG(1, "blkmtd: devname = %s\n", bdevname(rdev)); blocksize = BLOCK_SIZE; if(bs) { blocksize = bs; } else { if (blksize_size[maj] && blksize_size[maj][min]) { DEBUG(2, "blkmtd: blksize_size = %d\n", blksize_size[maj][min]); blocksize = blksize_size[maj][min]; } } i = blocksize; blocksize_bits = 0; while(i != 1) { blocksize_bits++; i >>= 1; } if(count) { size = count; } else { if (blk_size[maj]) { size = ((loff_t) blk_size[maj][min] << BLOCK_SIZE_BITS) >> blocksize_bits; } } total_sectors = size; size *= blocksize; totalsize = size; DEBUG(1, "blkmtd: size = %ld\n", (long int)size); if(size == 0) { printk("blkmtd: cant determine size\n"); return 1; } rawdevice = (mtd_raw_dev_data_t *)kmalloc(sizeof(mtd_raw_dev_data_t), GFP_KERNEL); if(rawdevice == NULL) { err = -ENOMEM; goto init_err; } memset(rawdevice, 0, sizeof(mtd_raw_dev_data_t)); // get the block device rawdevice->binding = bdget(kdev_t_to_nr(MKDEV(maj, min))); err = blkdev_get(rawdevice->binding, mode, 0, BDEV_RAW); if (err) { goto init_err; } rawdevice->totalsize = totalsize; rawdevice->total_sectors = total_sectors; rawdevice->sector_size = blocksize; rawdevice->sector_bits = blocksize_bits; rawdevice->readonly = readonly; DEBUG(2, "sector_size = %d, sector_bits = %d\n", rawdevice->sector_size, rawdevice->sector_bits); mtd_info = (struct mtd_info *)kmalloc(sizeof(struct mtd_info), GFP_KERNEL); if (mtd_info == NULL) { err = -ENOMEM; goto init_err; } memset(mtd_info, 0, sizeof(*mtd_info)); // Setup the MTD structure mtd_info->name = "blkmtd block device"; if(readonly) { mtd_info->type = MTD_ROM; mtd_info->flags = MTD_CAP_ROM; mtd_info->erasesize = erase_size << 10; } else { mtd_info->type = MTD_RAM; mtd_info->flags = MTD_CAP_RAM; mtd_info->erasesize = erase_size << 10; } mtd_info->size = size; mtd_info->erase = blkmtd_erase; mtd_info->read = blkmtd_read; mtd_info->write = blkmtd_write; mtd_info->sync = blkmtd_sync; mtd_info->point = 0; mtd_info->unpoint = 0; mtd_info->priv = rawdevice; regions = calc_erase_regions(NULL, erase_size << 10, size); DEBUG(1, "blkmtd: init: found %d erase regions\n", regions); mtd_info->eraseregions = kmalloc(regions * sizeof(struct mtd_erase_region_info), GFP_KERNEL); if(mtd_info->eraseregions == NULL) { } mtd_info->numeraseregions = regions; calc_erase_regions(mtd_info->eraseregions, erase_size << 10, size); /* setup the page cache info */ INIT_LIST_HEAD(&rawdevice->as.clean_pages); INIT_LIST_HEAD(&rawdevice->as.dirty_pages); INIT_LIST_HEAD(&rawdevice->as.locked_pages); rawdevice->as.nrpages = 0; rawdevice->as.a_ops = &blkmtd_aops; rawdevice->as.host = inode; rawdevice->as.i_mmap = NULL; rawdevice->as.i_mmap_shared = NULL; spin_lock_init(&rawdevice->as.i_shared_lock); rawdevice->as.gfp_mask = GFP_KERNEL; rawdevice->file = file; file->private_data = rawdevice; #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,2,0) mtd_info->module = THIS_MODULE; #endif if (add_mtd_device(mtd_info)) { err = -EIO; goto init_err; } init_waitqueue_head(&thr_wq); init_waitqueue_head(&mtbd_sync_wq); DEBUG(3, "blkmtd: init: kernel task @ %p\n", write_queue_task); DEBUG(2, "blkmtd: init: starting kernel task\n"); kernel_thread(write_queue_task, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGHAND); DEBUG(2, "blkmtd: init: started\n"); printk("blkmtd loaded: version = %s using %s erase_size = %dK %s\n", VERSION, device, erase_size, (readonly) ? "(read-only)" : ""); return 0; init_err: if(!rawdevice) { if(rawdevice->binding) blkdev_put(rawdevice->binding, BDEV_RAW); kfree(rawdevice); rawdevice = NULL; } if(mtd_info) { if(mtd_info->eraseregions) kfree(mtd_info->eraseregions); kfree(mtd_info); mtd_info = NULL; } return err; } module_init(init_blkmtd); module_exit(cleanup_blkmtd);