2  * block2mtd.c - create an mtd from a block device
5  * Copyright (C) 2004-2006	Joern Engel <joern@wh.fh-wedel.de>
23 #include <linux/backing-dev.h>
28 #include <linux/mtd/mtd.h>
34 /* Maximum number of comma-separated items in the 'block2mtd=' parameter */
41 	struct mtd_info mtd;  member
46 /* Static info about the MTD, used in cleanup_module */
58 	struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;  in _block2mtd_erase()
72 			if (*p != -1UL) {  in _block2mtd_erase()
82 		pages--;  in _block2mtd_erase()
87 static int block2mtd_erase(struct mtd_info *mtd, struct erase_info *instr)  in block2mtd_erase()  argument
89 	struct block2mtd_dev *dev = mtd->priv;  in block2mtd_erase()
90 	size_t from = instr->addr;  in block2mtd_erase()
91 	size_t len = instr->len;  in block2mtd_erase()
94 	mutex_lock(&dev->write_mutex);  in block2mtd_erase()
96 	mutex_unlock(&dev->write_mutex);  in block2mtd_erase()
104 static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,  in block2mtd_read()  argument
107 	struct block2mtd_dev *dev = mtd->priv;  in block2mtd_read()
110 	int offset = from & (PAGE_SIZE-1);  in block2mtd_read()
115 			cpylen = PAGE_SIZE - offset;	// multiple pages  in block2mtd_read()
118 		len = len - cpylen;  in block2mtd_read()
120 		page = page_read(dev->blkdev->bd_inode->i_mapping, index);  in block2mtd_read()
142 	struct address_space *mapping = dev->blkdev->bd_inode->i_mapping;  in _block2mtd_write()
149 			cpylen = PAGE_SIZE - offset;	// multiple pages  in _block2mtd_write()
152 		len = len - cpylen;  in _block2mtd_write()
178 static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,  in block2mtd_write()  argument
181 	struct block2mtd_dev *dev = mtd->priv;  in block2mtd_write()
184 	mutex_lock(&dev->write_mutex);  in block2mtd_write()
186 	mutex_unlock(&dev->write_mutex);  in block2mtd_write()
193 /* sync the device - wait until the write queue is empty */
194 static void block2mtd_sync(struct mtd_info *mtd)  in block2mtd_sync()  argument
196 	struct block2mtd_dev *dev = mtd->priv;  in block2mtd_sync()
197 	sync_blockdev(dev->blkdev);  in block2mtd_sync()
207 	kfree(dev->mtd.name);  in block2mtd_free_device()
209 	if (dev->blkdev) {  in block2mtd_free_device()
210 		invalidate_mapping_pages(dev->blkdev->bd_inode->i_mapping,  in block2mtd_free_device()
211 					0, -1);  in block2mtd_free_device()
212 		blkdev_put(dev->blkdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL);  in block2mtd_free_device()
228 	char *name;  in add_device()  local
243 	 * Try to resolve the device name by other means.  in add_device()
252 			 * go-arounds.  in add_device()
268 	dev->blkdev = bdev;  in add_device()
270 	if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {  in add_device()
271 		pr_err("attempting to use an MTD device as a block device\n");  in add_device()
275 	if ((long)dev->blkdev->bd_inode->i_size % erase_size) {  in add_device()
280 	mutex_init(&dev->write_mutex);  in add_device()
282 	/* Setup the MTD structure */  in add_device()
283 	/* make the name contain the block device in */  in add_device()
285 		name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);  in add_device()
287 		name = kstrdup(label, GFP_KERNEL);  in add_device()
288 	if (!name)  in add_device()
291 	dev->mtd.name = name;  in add_device()
293 	dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK;  in add_device()
294 	dev->mtd.erasesize = erase_size;  in add_device()
295 	dev->mtd.writesize = 1;  in add_device()
296 	dev->mtd.writebufsize = PAGE_SIZE;  in add_device()
297 	dev->mtd.type = MTD_RAM;  in add_device()
298 	dev->mtd.flags = MTD_CAP_RAM;  in add_device()
299 	dev->mtd._erase = block2mtd_erase;  in add_device()
300 	dev->mtd._write = block2mtd_write;  in add_device()
301 	dev->mtd._sync = block2mtd_sync;  in add_device()
302 	dev->mtd._read = block2mtd_read;  in add_device()
303 	dev->mtd.priv = dev;  in add_device()
304 	dev->mtd.owner = THIS_MODULE;  in add_device()
306 	if (mtd_device_register(&dev->mtd, NULL, 0)) {  in add_device()
311 	list_add(&dev->list, &blkmtd_device_list);  in add_device()
312 	pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n",  in add_device()
313 		dev->mtd.index,  in add_device()
314 		label ? label : dev->mtd.name + strlen("block2mtd: "),  in add_device()
315 		dev->mtd.erasesize >> 10, dev->mtd.erasesize);  in add_device()
319 	mutex_destroy(&dev->write_mutex);  in add_device()
327  * allows some suffixes for a more human-readable number format:
328  * ki, Ki, kiB, KiB	- multiply result with 1024
329  * Mi, MiB		- multiply result with 1024^2
330  * Gi, GiB		- multiply result with 1024^3
364 		return -EINVAL;  in parse_num()
387 	/* 80 for device, 12 for erase size, 80 for name, 8 for timeout */  in block2mtd_setup2()
391 	char *name;  in block2mtd_setup2()  local
418 	name = token[0];  in block2mtd_setup2()
419 	if (strlen(name) + 1 > 80) {  in block2mtd_setup2()
420 		pr_err("device name too long\n");  in block2mtd_setup2()
435 		pr_info("Using custom MTD label '%s' for dev %s\n", label, name);  in block2mtd_setup2()
438 	add_device(name, erase_size, label, timeout);  in block2mtd_setup2()
492 	/* Remove the MTD devices */  in block2mtd_exit()
495 		block2mtd_sync(&dev->mtd);  in block2mtd_exit()
496 		mtd_device_unregister(&dev->mtd);  in block2mtd_exit()
497 		mutex_destroy(&dev->write_mutex);  in block2mtd_exit()
498 		pr_info("mtd%d: [%s] removed\n",  in block2mtd_exit()
499 			dev->mtd.index,  in block2mtd_exit()
500 			dev->mtd.name + strlen("block2mtd: "));  in block2mtd_exit()
501 		list_del(&dev->list);  in block2mtd_exit()
511 MODULE_DESCRIPTION("Emulate an MTD using a block device");