1 // SPDX-License-Identifier: GPL-2.0-or-later
9  * This is a small driver which implements fake MTD devices on top of UBI
11  * MTD-oriented software (including all the legacy software) work on top of
14  * Gluebi emulates MTD devices of "MTD_UBIVOLUME" type. Their minimal I/O unit
15  * size (@mtd->writesize) is equivalent to the UBI minimal I/O unit. The
26 #include <linux/mtd/ubi.h>
27 #include <linux/mtd/mtd.h>
28 #include "ubi-media.h"
32 	       current->pid, __func__, ##__VA_ARGS__)
35  * struct gluebi_device - a gluebi device description data structure.
36  * @mtd: emulated MTD device description object
44 	struct mtd_info mtd;  member
57  * find_gluebi_nolock - find a gluebi device.
71 		if (gluebi->ubi_num == ubi_num && gluebi->vol_id == vol_id)  in find_gluebi_nolock()
77  * gluebi_get_device - get MTD device reference.
78  * @mtd: the MTD device description object
80  * This function is called every time the MTD device is being opened and
81  * implements the MTD get_device() operation. Returns zero in case of success
84 static int gluebi_get_device(struct mtd_info *mtd)  in gluebi_get_device()  argument
89 	if (mtd->flags & MTD_WRITEABLE)  in gluebi_get_device()
92 	gluebi = container_of(mtd, struct gluebi_device, mtd);  in gluebi_get_device()
94 	if (gluebi->refcnt > 0) {  in gluebi_get_device()
96 		 * The MTD device is already referenced and this is just one  in gluebi_get_device()
97 		 * more reference. MTD allows many users to open the same  in gluebi_get_device()
100 		 * not open the UBI volume again - just increase the reference  in gluebi_get_device()
103 		gluebi->refcnt += 1;  in gluebi_get_device()
109 	 * This is the first reference to this UBI volume via the MTD device  in gluebi_get_device()
110 	 * interface. Open the corresponding volume in read-write mode.  in gluebi_get_device()
112 	gluebi->desc = ubi_open_volume(gluebi->ubi_num, gluebi->vol_id,  in gluebi_get_device()
114 	if (IS_ERR(gluebi->desc)) {  in gluebi_get_device()
116 		return PTR_ERR(gluebi->desc);  in gluebi_get_device()
118 	gluebi->refcnt += 1;  in gluebi_get_device()
124  * gluebi_put_device - put MTD device reference.
125  * @mtd: the MTD device description object
127  * This function is called every time the MTD device is being put. Returns
130 static void gluebi_put_device(struct mtd_info *mtd)  in gluebi_put_device()  argument
134 	gluebi = container_of(mtd, struct gluebi_device, mtd);  in gluebi_put_device()
136 	gluebi->refcnt -= 1;  in gluebi_put_device()
137 	if (gluebi->refcnt == 0)  in gluebi_put_device()
138 		ubi_close_volume(gluebi->desc);  in gluebi_put_device()
143  * gluebi_read - read operation of emulated MTD devices.
144  * @mtd: MTD device description object
153 static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,  in gluebi_read()  argument
159 	gluebi = container_of(mtd, struct gluebi_device, mtd);  in gluebi_read()
160 	lnum = div_u64_rem(from, mtd->erasesize, &offs);  in gluebi_read()
163 		size_t to_read = mtd->erasesize - offs;  in gluebi_read()
168 		err = ubi_read(gluebi->desc, lnum, buf, offs, to_read);  in gluebi_read()
174 		bytes_left -= to_read;  in gluebi_read()
178 	*retlen = len - bytes_left;  in gluebi_read()
183  * gluebi_write - write operation of emulated MTD devices.
184  * @mtd: MTD device description object
193 static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,  in gluebi_write()  argument
199 	gluebi = container_of(mtd, struct gluebi_device, mtd);  in gluebi_write()
200 	lnum = div_u64_rem(to, mtd->erasesize, &offs);  in gluebi_write()
202 	if (len % mtd->writesize || offs % mtd->writesize)  in gluebi_write()
203 		return -EINVAL;  in gluebi_write()
207 		size_t to_write = mtd->erasesize - offs;  in gluebi_write()
212 		err = ubi_leb_write(gluebi->desc, lnum, buf, offs, to_write);  in gluebi_write()
218 		bytes_left -= to_write;  in gluebi_write()
222 	*retlen = len - bytes_left;  in gluebi_write()
227  * gluebi_erase - erase operation of emulated MTD devices.
228  * @mtd: the MTD device description object
234 static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr)  in gluebi_erase()  argument
239 	if (mtd_mod_by_ws(instr->addr, mtd) || mtd_mod_by_ws(instr->len, mtd))  in gluebi_erase()
240 		return -EINVAL;  in gluebi_erase()
242 	lnum = mtd_div_by_eb(instr->addr, mtd);  in gluebi_erase()
243 	count = mtd_div_by_eb(instr->len, mtd);  in gluebi_erase()
244 	gluebi = container_of(mtd, struct gluebi_device, mtd);  in gluebi_erase()
246 	for (i = 0; i < count - 1; i++) {  in gluebi_erase()
247 		err = ubi_leb_unmap(gluebi->desc, lnum + i);  in gluebi_erase()
252 	 * MTD erase operations are synchronous, so we have to make sure the  in gluebi_erase()
255 	 * Thus, perform leb_erase instead of leb_unmap operation - leb_erase  in gluebi_erase()
258 	err = ubi_leb_erase(gluebi->desc, lnum + i);  in gluebi_erase()
265 	instr->fail_addr = (long long)lnum * mtd->erasesize;  in gluebi_erase()
270  * gluebi_create - create a gluebi device for an UBI volume.
275  * corresponding fake MTD device. Returns zero in case of success and a
282 	struct mtd_info *mtd;  in gluebi_create()  local
286 		return -ENOMEM;  in gluebi_create()
288 	mtd = &gluebi->mtd;  in gluebi_create()
289 	mtd->name = kmemdup(vi->name, vi->name_len + 1, GFP_KERNEL);  in gluebi_create()
290 	if (!mtd->name) {  in gluebi_create()
292 		return -ENOMEM;  in gluebi_create()
295 	gluebi->vol_id = vi->vol_id;  in gluebi_create()
296 	gluebi->ubi_num = vi->ubi_num;  in gluebi_create()
297 	mtd->type = MTD_UBIVOLUME;  in gluebi_create()
298 	if (!di->ro_mode)  in gluebi_create()
299 		mtd->flags = MTD_WRITEABLE;  in gluebi_create()
300 	mtd->owner      = THIS_MODULE;  in gluebi_create()
301 	mtd->writesize  = di->min_io_size;  in gluebi_create()
302 	mtd->erasesize  = vi->usable_leb_size;  in gluebi_create()
303 	mtd->_read       = gluebi_read;  in gluebi_create()
304 	mtd->_write      = gluebi_write;  in gluebi_create()
305 	mtd->_erase      = gluebi_erase;  in gluebi_create()
306 	mtd->_get_device = gluebi_get_device;  in gluebi_create()
307 	mtd->_put_device = gluebi_put_device;  in gluebi_create()
310 	 * In case of dynamic a volume, MTD device size is just volume size. In  in gluebi_create()
314 	if (vi->vol_type == UBI_DYNAMIC_VOLUME)  in gluebi_create()
315 		mtd->size = (unsigned long long)vi->usable_leb_size * vi->size;  in gluebi_create()
317 		mtd->size = vi->used_bytes;  in gluebi_create()
319 	/* Just a sanity check - make sure this gluebi device does not exist */  in gluebi_create()
321 	g = find_gluebi_nolock(vi->ubi_num, vi->vol_id);  in gluebi_create()
323 		err_msg("gluebi MTD device %d form UBI device %d volume %d already exists",  in gluebi_create()
324 			g->mtd.index, vi->ubi_num, vi->vol_id);  in gluebi_create()
327 	if (mtd_device_register(mtd, NULL, 0)) {  in gluebi_create()
328 		err_msg("cannot add MTD device");  in gluebi_create()
329 		kfree(mtd->name);  in gluebi_create()
331 		return -ENFILE;  in gluebi_create()
335 	list_add_tail(&gluebi->list, &gluebi_devices);  in gluebi_create()
341  * gluebi_remove - remove a gluebi device.
345  * corresponding fake MTD device. Returns zero in case of success and a
351 	struct mtd_info *mtd;  in gluebi_remove()  local
355 	gluebi = find_gluebi_nolock(vi->ubi_num, vi->vol_id);  in gluebi_remove()
358 			vi->ubi_num, vi->vol_id);  in gluebi_remove()
359 		err = -ENOENT;  in gluebi_remove()
360 	} else if (gluebi->refcnt)  in gluebi_remove()
361 		err = -EBUSY;  in gluebi_remove()
363 		list_del(&gluebi->list);  in gluebi_remove()
368 	mtd = &gluebi->mtd;  in gluebi_remove()
369 	err = mtd_device_unregister(mtd);  in gluebi_remove()
371 		err_msg("cannot remove fake MTD device %d, UBI device %d, volume %d, error %d",  in gluebi_remove()
372 			mtd->index, gluebi->ubi_num, gluebi->vol_id, err);  in gluebi_remove()
374 		list_add_tail(&gluebi->list, &gluebi_devices);  in gluebi_remove()
379 	kfree(mtd->name);  in gluebi_remove()
385  * gluebi_updated - UBI volume was updated notifier.
389  * if te volume @vol is dynamic, and changes MTD device size if the
399 	gluebi = find_gluebi_nolock(vi->ubi_num, vi->vol_id);  in gluebi_updated()
403 			vi->ubi_num, vi->vol_id);  in gluebi_updated()
404 		return -ENOENT;  in gluebi_updated()
407 	if (vi->vol_type == UBI_STATIC_VOLUME)  in gluebi_updated()
408 		gluebi->mtd.size = vi->used_bytes;  in gluebi_updated()
414  * gluebi_resized - UBI volume was re-sized notifier.
417  * This function is called every time an UBI volume is re-size. It changes the
418  * corresponding fake MTD device size. This function returns zero in case of
426 	gluebi = find_gluebi_nolock(vi->ubi_num, vi->vol_id);  in gluebi_resized()
430 			vi->ubi_num, vi->vol_id);  in gluebi_resized()
431 		return -ENOENT;  in gluebi_resized()
433 	gluebi->mtd.size = vi->used_bytes;  in gluebi_resized()
439  * gluebi_notify - UBI notification handler.
451 		gluebi_create(&nt->di, &nt->vi);  in gluebi_notify()
454 		gluebi_remove(&nt->vi);  in gluebi_notify()
457 		gluebi_resized(&nt->vi);  in gluebi_notify()
460 		gluebi_updated(&nt->vi);  in gluebi_notify()
483 		struct mtd_info *mtd = &gluebi->mtd;  in ubi_gluebi_exit()  local
485 		err = mtd_device_unregister(mtd);  in ubi_gluebi_exit()
487 			err_msg("error %d while removing gluebi MTD device %d, UBI device %d, volume %d - ignoring",  in ubi_gluebi_exit()
488 				err, mtd->index, gluebi->ubi_num,  in ubi_gluebi_exit()
489 				gluebi->vol_id);  in ubi_gluebi_exit()
490 		kfree(mtd->name);  in ubi_gluebi_exit()
498 MODULE_DESCRIPTION("MTD emulation layer over UBI volumes");