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 */
59 				dev->bdev_handle->bdev->bd_inode->i_mapping;  in _block2mtd_erase()
73 			if (*p != -1UL) {  in _block2mtd_erase()
83 		pages--;  in _block2mtd_erase()
88 static int block2mtd_erase(struct mtd_info *mtd, struct erase_info *instr)  in block2mtd_erase()  argument
90 	struct block2mtd_dev *dev = mtd->priv;  in block2mtd_erase()
91 	size_t from = instr->addr;  in block2mtd_erase()
92 	size_t len = instr->len;  in block2mtd_erase()
95 	mutex_lock(&dev->write_mutex);  in block2mtd_erase()
97 	mutex_unlock(&dev->write_mutex);  in block2mtd_erase()
105 static int block2mtd_read(struct mtd_info *mtd, loff_t from, size_t len,  in block2mtd_read()  argument
108 	struct block2mtd_dev *dev = mtd->priv;  in block2mtd_read()
110 				dev->bdev_handle->bdev->bd_inode->i_mapping;  in block2mtd_read()
113 	int offset = from & (PAGE_SIZE-1);  in block2mtd_read()
118 			cpylen = PAGE_SIZE - offset;	// multiple pages  in block2mtd_read()
121 		len = len - cpylen;  in block2mtd_read()
146 				dev->bdev_handle->bdev->bd_inode->i_mapping;  in _block2mtd_write()
153 			cpylen = PAGE_SIZE - offset;	// multiple pages  in _block2mtd_write()
156 		len = len - cpylen;  in _block2mtd_write()
182 static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,  in block2mtd_write()  argument
185 	struct block2mtd_dev *dev = mtd->priv;  in block2mtd_write()
188 	mutex_lock(&dev->write_mutex);  in block2mtd_write()
190 	mutex_unlock(&dev->write_mutex);  in block2mtd_write()
197 /* sync the device - wait until the write queue is empty */
198 static void block2mtd_sync(struct mtd_info *mtd)  in block2mtd_sync()  argument
200 	struct block2mtd_dev *dev = mtd->priv;  in block2mtd_sync()
201 	sync_blockdev(dev->bdev_handle->bdev);  in block2mtd_sync()
211 	kfree(dev->mtd.name);  in block2mtd_free_device()
213 	if (dev->bdev_handle) {  in block2mtd_free_device()
215 			dev->bdev_handle->bdev->bd_inode->i_mapping, 0, -1);  in block2mtd_free_device()
216 		bdev_release(dev->bdev_handle);  in block2mtd_free_device()
229 	struct bdev_handle *bdev_handle = ERR_PTR(-ENODEV);  in mdtblock_early_get_bdev()
241 	 * Try to resolve the device name by other means.  in mdtblock_early_get_bdev()
250 			 * go-arounds.  in mdtblock_early_get_bdev()
272 	char *name;  in add_device()  local
290 	dev->bdev_handle = bdev_handle;  in add_device()
291 	bdev = bdev_handle->bdev;  in add_device()
293 	if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {  in add_device()
294 		pr_err("attempting to use an MTD device as a block device\n");  in add_device()
298 	if ((long)bdev->bd_inode->i_size % erase_size) {  in add_device()
303 	mutex_init(&dev->write_mutex);  in add_device()
305 	/* Setup the MTD structure */  in add_device()
306 	/* make the name contain the block device in */  in add_device()
308 		name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);  in add_device()
310 		name = kstrdup(label, GFP_KERNEL);  in add_device()
311 	if (!name)  in add_device()
314 	dev->mtd.name = name;  in add_device()
316 	dev->mtd.size = bdev->bd_inode->i_size & PAGE_MASK;  in add_device()
317 	dev->mtd.erasesize = erase_size;  in add_device()
318 	dev->mtd.writesize = 1;  in add_device()
319 	dev->mtd.writebufsize = PAGE_SIZE;  in add_device()
320 	dev->mtd.type = MTD_RAM;  in add_device()
321 	dev->mtd.flags = MTD_CAP_RAM;  in add_device()
322 	dev->mtd._erase = block2mtd_erase;  in add_device()
323 	dev->mtd._write = block2mtd_write;  in add_device()
324 	dev->mtd._sync = block2mtd_sync;  in add_device()
325 	dev->mtd._read = block2mtd_read;  in add_device()
326 	dev->mtd.priv = dev;  in add_device()
327 	dev->mtd.owner = THIS_MODULE;  in add_device()
329 	if (mtd_device_register(&dev->mtd, NULL, 0)) {  in add_device()
334 	list_add(&dev->list, &blkmtd_device_list);  in add_device()
335 	pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n",  in add_device()
336 		dev->mtd.index,  in add_device()
337 		label ? label : dev->mtd.name + strlen("block2mtd: "),  in add_device()
338 		dev->mtd.erasesize >> 10, dev->mtd.erasesize);  in add_device()
342 	mutex_destroy(&dev->write_mutex);  in add_device()
350  * allows some suffixes for a more human-readable number format:
351  * ki, Ki, kiB, KiB	- multiply result with 1024
352  * Mi, MiB		- multiply result with 1024^2
353  * Gi, GiB		- multiply result with 1024^3
387 		return -EINVAL;  in parse_num()
410 	/* 80 for device, 12 for erase size, 80 for name, 8 for timeout */  in block2mtd_setup2()
414 	char *name;  in block2mtd_setup2()  local
441 	name = token[0];  in block2mtd_setup2()
442 	if (strlen(name) + 1 > 80) {  in block2mtd_setup2()
443 		pr_err("device name too long\n");  in block2mtd_setup2()
458 		pr_info("Using custom MTD label '%s' for dev %s\n", label, name);  in block2mtd_setup2()
461 	add_device(name, erase_size, label, timeout);  in block2mtd_setup2()
515 	/* Remove the MTD devices */  in block2mtd_exit()
518 		block2mtd_sync(&dev->mtd);  in block2mtd_exit()
519 		mtd_device_unregister(&dev->mtd);  in block2mtd_exit()
520 		mutex_destroy(&dev->write_mutex);  in block2mtd_exit()
521 		pr_info("mtd%d: [%s] removed\n",  in block2mtd_exit()
522 			dev->mtd.index,  in block2mtd_exit()
523 			dev->mtd.name + strlen("block2mtd: "));  in block2mtd_exit()
524 		list_del(&dev->list);  in block2mtd_exit()
534 MODULE_DESCRIPTION("Emulate an MTD using a block device");