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->bdev_file->f_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()
108 	struct address_space *mapping = dev->bdev_file->f_mapping;  in block2mtd_read()
111 	int offset = from & (PAGE_SIZE-1);  in block2mtd_read()
116 			cpylen = PAGE_SIZE - offset;	// multiple pages  in block2mtd_read()
119 		len = len - cpylen;  in block2mtd_read()
143 	struct address_space *mapping = dev->bdev_file->f_mapping;  in _block2mtd_write()
150 			cpylen = PAGE_SIZE - offset;	// multiple pages  in _block2mtd_write()
153 		len = len - cpylen;  in _block2mtd_write()
179 static int block2mtd_write(struct mtd_info *mtd, loff_t to, size_t len,  in block2mtd_write()  argument
182 	struct block2mtd_dev *dev = mtd->priv;  in block2mtd_write()
185 	mutex_lock(&dev->write_mutex);  in block2mtd_write()
187 	mutex_unlock(&dev->write_mutex);  in block2mtd_write()
194 /* sync the device - wait until the write queue is empty */
195 static void block2mtd_sync(struct mtd_info *mtd)  in block2mtd_sync()  argument
197 	struct block2mtd_dev *dev = mtd->priv;  in block2mtd_sync()
198 	sync_blockdev(file_bdev(dev->bdev_file));  in block2mtd_sync()
208 	kfree(dev->mtd.name);  in block2mtd_free_device()
210 	if (dev->bdev_file) {  in block2mtd_free_device()
211 		invalidate_mapping_pages(dev->bdev_file->f_mapping, 0, -1);  in block2mtd_free_device()
212 		bdev_fput(dev->bdev_file);  in block2mtd_free_device()
225 	struct file *bdev_file = ERR_PTR(-ENODEV);  in mdtblock_early_get_bdev()
237 	 * Try to resolve the device name by other means.  in mdtblock_early_get_bdev()
246 			 * go-arounds.  in mdtblock_early_get_bdev()
269 	char *name;  in add_device()  local
287 	dev->bdev_file = bdev_file;  in add_device()
290 	if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {  in add_device()
291 		pr_err("attempting to use an MTD device as a block device\n");  in add_device()
301 	mutex_init(&dev->write_mutex);  in add_device()
303 	/* Setup the MTD structure */  in add_device()
304 	/* make the name contain the block device in */  in add_device()
306 		name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);  in add_device()
308 		name = kstrdup(label, GFP_KERNEL);  in add_device()
309 	if (!name)  in add_device()
312 	dev->mtd.name = name;  in add_device()
314 	dev->mtd.size = size & PAGE_MASK;  in add_device()
315 	dev->mtd.erasesize = erase_size;  in add_device()
316 	dev->mtd.writesize = 1;  in add_device()
317 	dev->mtd.writebufsize = PAGE_SIZE;  in add_device()
318 	dev->mtd.type = MTD_RAM;  in add_device()
319 	dev->mtd.flags = MTD_CAP_RAM;  in add_device()
320 	dev->mtd._erase = block2mtd_erase;  in add_device()
321 	dev->mtd._write = block2mtd_write;  in add_device()
322 	dev->mtd._sync = block2mtd_sync;  in add_device()
323 	dev->mtd._read = block2mtd_read;  in add_device()
324 	dev->mtd.priv = dev;  in add_device()
325 	dev->mtd.owner = THIS_MODULE;  in add_device()
327 	if (mtd_device_register(&dev->mtd, NULL, 0)) {  in add_device()
332 	list_add(&dev->list, &blkmtd_device_list);  in add_device()
333 	pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n",  in add_device()
334 		dev->mtd.index,  in add_device()
335 		label ? label : dev->mtd.name + strlen("block2mtd: "),  in add_device()
336 		dev->mtd.erasesize >> 10, dev->mtd.erasesize);  in add_device()
340 	mutex_destroy(&dev->write_mutex);  in add_device()
348  * allows some suffixes for a more human-readable number format:
349  * ki, Ki, kiB, KiB	- multiply result with 1024
350  * Mi, MiB		- multiply result with 1024^2
351  * Gi, GiB		- multiply result with 1024^3
385 		return -EINVAL;  in parse_num()
408 	/* 80 for device, 12 for erase size, 80 for name, 8 for timeout */  in block2mtd_setup2()
412 	char *name;  in block2mtd_setup2()  local
439 	name = token[0];  in block2mtd_setup2()
440 	if (strlen(name) + 1 > 80) {  in block2mtd_setup2()
441 		pr_err("device name too long\n");  in block2mtd_setup2()
456 		pr_info("Using custom MTD label '%s' for dev %s\n", label, name);  in block2mtd_setup2()
459 	add_device(name, erase_size, label, timeout);  in block2mtd_setup2()
513 	/* Remove the MTD devices */  in block2mtd_exit()
516 		block2mtd_sync(&dev->mtd);  in block2mtd_exit()
517 		mtd_device_unregister(&dev->mtd);  in block2mtd_exit()
518 		mutex_destroy(&dev->write_mutex);  in block2mtd_exit()
519 		pr_info("mtd%d: [%s] removed\n",  in block2mtd_exit()
520 			dev->mtd.index,  in block2mtd_exit()
521 			dev->mtd.name + strlen("block2mtd: "));  in block2mtd_exit()
522 		list_del(&dev->list);  in block2mtd_exit()
532 MODULE_DESCRIPTION("Emulate an MTD using a block device");