[linux.git] / drivers / mtd / ubi / gluebi.c

/*
 * Copyright (c) International Business Machines Corp., 2006
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
 * the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Author: Artem Bityutskiy (Битюцкий Артём), Joern Engel
 */

/*
 * This file includes implementation of fake MTD devices for each UBI volume.
 * This sounds strange, but it is in fact quite useful to make MTD-oriented
 * software (including all the legacy software) to work on top of UBI.
 *
 * Gluebi emulates MTD devices of "MTD_UBIVOLUME" type. Their minimal I/O unit
 * size (mtd->writesize) is equivalent to the UBI minimal I/O unit. The
 * eraseblock size is equivalent to the logical eraseblock size of the volume.
 */

#include <asm/div64.h>
#include "ubi.h"

/**
 * gluebi_get_device - get MTD device reference.
 * @mtd: the MTD device description object
 *
 * This function is called every time the MTD device is being opened and
 * implements the MTD get_device() operation. Returns zero in case of success
 * and a negative error code in case of failure.
 */
static int gluebi_get_device(struct mtd_info *mtd)
{
	struct ubi_volume *vol;

	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);

	/*
	 * We do not introduce locks for gluebi reference count because the
	 * get_device()/put_device() calls are already serialized at MTD.
	 */
	if (vol->gluebi_refcount > 0) {
		/*
		 * The MTD device is already referenced and this is just one
		 * more reference. MTD allows many users to open the same
		 * volume simultaneously and do not distinguish between
		 * readers/writers/exclusive openers as UBI does. So we do not
		 * open the UBI volume again - just increase the reference
		 * counter and return.
		 */
		vol->gluebi_refcount += 1;
		return 0;
	}

	/*
	 * This is the first reference to this UBI volume via the MTD device
	 * interface. Open the corresponding volume in read-write mode.
	 */
	vol->gluebi_desc = ubi_open_volume(vol->ubi->ubi_num, vol->vol_id,
					   UBI_READWRITE);
	if (IS_ERR(vol->gluebi_desc))
		return PTR_ERR(vol->gluebi_desc);
	vol->gluebi_refcount += 1;
	return 0;
}

/**
 * gluebi_put_device - put MTD device reference.
 * @mtd: the MTD device description object
 *
 * This function is called every time the MTD device is being put. Returns
 * zero in case of success and a negative error code in case of failure.
 */
static void gluebi_put_device(struct mtd_info *mtd)
{
	struct ubi_volume *vol;

	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
	vol->gluebi_refcount -= 1;
	ubi_assert(vol->gluebi_refcount >= 0);
	if (vol->gluebi_refcount == 0)
		ubi_close_volume(vol->gluebi_desc);
}

/**
 * gluebi_read - read operation of emulated MTD devices.
 * @mtd: MTD device description object
 * @from: absolute offset from where to read
 * @len: how many bytes to read
 * @retlen: count of read bytes is returned here
 * @buf: buffer to store the read data
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 */
static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,
		       size_t *retlen, unsigned char *buf)
{
	int err = 0, lnum, offs, total_read;
	struct ubi_volume *vol;
	struct ubi_device *ubi;
	uint64_t tmp = from;

	dbg_gen("read %zd bytes from offset %lld", len, from);

	if (len < 0 || from < 0 || from + len > mtd->size)
		return -EINVAL;

	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
	ubi = vol->ubi;

	offs = do_div(tmp, mtd->erasesize);
	lnum = tmp;

	total_read = len;
	while (total_read) {
		size_t to_read = mtd->erasesize - offs;

		if (to_read > total_read)
			to_read = total_read;

		err = ubi_eba_read_leb(ubi, vol, lnum, buf, offs, to_read, 0);
		if (err)
			break;

		lnum += 1;
		offs = 0;
		total_read -= to_read;
		buf += to_read;
	}

	*retlen = len - total_read;
	return err;
}

/**
 * gluebi_write - write operation of emulated MTD devices.
 * @mtd: MTD device description object
 * @to: absolute offset where to write
 * @len: how many bytes to write
 * @retlen: count of written bytes is returned here
 * @buf: buffer with data to write
 *
 * This function returns zero in case of success and a negative error code in
 * case of failure.
 */
static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
		       size_t *retlen, const u_char *buf)
{
	int err = 0, lnum, offs, total_written;
	struct ubi_volume *vol;
	struct ubi_device *ubi;
	uint64_t tmp = to;

	dbg_gen("write %zd bytes to offset %lld", len, to);

	if (len < 0 || to < 0 || len + to > mtd->size)
		return -EINVAL;

	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
	ubi = vol->ubi;

	if (ubi->ro_mode)
		return -EROFS;

	offs = do_div(tmp, mtd->erasesize);
	lnum = tmp;

	if (len % mtd->writesize || offs % mtd->writesize)
		return -EINVAL;

	total_written = len;
	while (total_written) {
		size_t to_write = mtd->erasesize - offs;

		if (to_write > total_written)
			to_write = total_written;

		err = ubi_eba_write_leb(ubi, vol, lnum, buf, offs, to_write,
					UBI_UNKNOWN);
		if (err)
			break;

		lnum += 1;
		offs = 0;
		total_written -= to_write;
		buf += to_write;
	}

	*retlen = len - total_written;
	return err;
}

/**
 * gluebi_erase - erase operation of emulated MTD devices.
 * @mtd: the MTD device description object
 * @instr: the erase operation description
 *
 * This function calls the erase callback when finishes. Returns zero in case
 * of success and a negative error code in case of failure.
 */
static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr)
{
	int err, i, lnum, count;
	struct ubi_volume *vol;
	struct ubi_device *ubi;

	dbg_gen("erase %u bytes at offset %u", instr->len, instr->addr);

	if (instr->addr < 0 || instr->addr > mtd->size - mtd->erasesize)
		return -EINVAL;

	if (instr->len < 0 || instr->addr + instr->len > mtd->size)
		return -EINVAL;

	if (instr->addr % mtd->writesize || instr->len % mtd->writesize)
		return -EINVAL;

	lnum = instr->addr / mtd->erasesize;
	count = instr->len / mtd->erasesize;

	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
	ubi = vol->ubi;

	if (ubi->ro_mode)
		return -EROFS;

	for (i = 0; i < count; i++) {
		err = ubi_eba_unmap_leb(ubi, vol, lnum + i);
		if (err)
			goto out_err;
	}

	/*
	 * MTD erase operations are synchronous, so we have to make sure the
	 * physical eraseblock is wiped out.
	 */
	err = ubi_wl_flush(ubi);
	if (err)
		goto out_err;

	instr->state = MTD_ERASE_DONE;
	mtd_erase_callback(instr);
	return 0;

out_err:
	instr->state = MTD_ERASE_FAILED;
	instr->fail_addr = lnum * mtd->erasesize;
	return err;
}

/**
 * ubi_create_gluebi - initialize gluebi for an UBI volume.
 * @ubi: UBI device description object
 * @vol: volume description object
 *
 * This function is called when an UBI volume is created in order to create
 * corresponding fake MTD device. Returns zero in case of success and a
 * negative error code in case of failure.
 */
int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol)
{
	struct mtd_info *mtd = &vol->gluebi_mtd;

	mtd->name = kmemdup(vol->name, vol->name_len + 1, GFP_KERNEL);
	if (!mtd->name)
		return -ENOMEM;

	mtd->type = MTD_UBIVOLUME;
	if (!ubi->ro_mode)
		mtd->flags = MTD_WRITEABLE;
	mtd->writesize  = ubi->min_io_size;
	mtd->owner      = THIS_MODULE;
	mtd->erasesize  = vol->usable_leb_size;
	mtd->read       = gluebi_read;
	mtd->write      = gluebi_write;
	mtd->erase      = gluebi_erase;
	mtd->get_device = gluebi_get_device;
	mtd->put_device = gluebi_put_device;

	/*
	 * In case of dynamic volume, MTD device size is just volume size. In
	 * case of a static volume the size is equivalent to the amount of data
	 * bytes.
	 */
	if (vol->vol_type == UBI_DYNAMIC_VOLUME)
		mtd->size = vol->usable_leb_size * vol->reserved_pebs;
	else
		mtd->size = vol->used_bytes;

	if (add_mtd_device(mtd)) {
		ubi_err("cannot not add MTD device");
		kfree(mtd->name);
		return -ENFILE;
	}

	dbg_gen("added mtd%d (\"%s\"), size %u, EB size %u",
		mtd->index, mtd->name, mtd->size, mtd->erasesize);
	return 0;
}

/**
 * ubi_destroy_gluebi - close gluebi for an UBI volume.
 * @vol: volume description object
 *
 * This function is called when an UBI volume is removed in order to remove
 * corresponding fake MTD device. Returns zero in case of success and a
 * negative error code in case of failure.
 */
int ubi_destroy_gluebi(struct ubi_volume *vol)
{
	int err;
	struct mtd_info *mtd = &vol->gluebi_mtd;

	dbg_gen("remove mtd%d", mtd->index);
	err = del_mtd_device(mtd);
	if (err)
		return err;
	kfree(mtd->name);
	return 0;
}

/**
 * ubi_gluebi_updated - UBI volume was updated notifier.
 * @vol: volume description object
 *
 * This function is called every time an UBI volume is updated. This function
 * does nothing if volume @vol is dynamic, and changes MTD device size if the
 * volume is static. This is needed because static volumes cannot be read past
 * data they contain.
 */
void ubi_gluebi_updated(struct ubi_volume *vol)
{
	struct mtd_info *mtd = &vol->gluebi_mtd;

	if (vol->vol_type == UBI_STATIC_VOLUME)
		mtd->size = vol->used_bytes;
}
Commit	Line	Data
801c135c AB	1	/*
	2	* Copyright (c) International Business Machines Corp., 2006
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License as published by
	6	* the Free Software Foundation; either version 2 of the License, or
	7	* (at your option) any later version.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
	12	* the GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write to the Free Software
	16	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	17	*
	18	* Author: Artem Bityutskiy (Битюцкий Артём), Joern Engel
	19	*/
	20
	21	/*
	22	* This file includes implementation of fake MTD devices for each UBI volume.
	23	* This sounds strange, but it is in fact quite useful to make MTD-oriented
	24	* software (including all the legacy software) to work on top of UBI.
	25	*
	26	* Gluebi emulates MTD devices of "MTD_UBIVOLUME" type. Their minimal I/O unit
	27	* size (mtd->writesize) is equivalent to the UBI minimal I/O unit. The
	28	* eraseblock size is equivalent to the logical eraseblock size of the volume.
	29	*/
	30
	31	#include <asm/div64.h>
	32	#include "ubi.h"
	33
	34	/**
	35	* gluebi_get_device - get MTD device reference.
	36	* @mtd: the MTD device description object
	37	*
	38	* This function is called every time the MTD device is being opened and
	39	* implements the MTD get_device() operation. Returns zero in case of success
	40	* and a negative error code in case of failure.
	41	*/
	42	static int gluebi_get_device(struct mtd_info *mtd)
	43	{
	44	struct ubi_volume *vol;
	45
	46	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
	47
	48	/*
	49	* We do not introduce locks for gluebi reference count because the
	50	* get_device()/put_device() calls are already serialized at MTD.
	51	*/
	52	if (vol->gluebi_refcount > 0) {
	53	/*
	54	* The MTD device is already referenced and this is just one
	55	* more reference. MTD allows many users to open the same
	56	* volume simultaneously and do not distinguish between
	57	* readers/writers/exclusive openers as UBI does. So we do not
	58	* open the UBI volume again - just increase the reference
	59	* counter and return.
	60	*/
	61	vol->gluebi_refcount += 1;
	62	return 0;
	63	}
	64
65	/*
66	* This is the first reference to this UBI volume via the MTD device
67	* interface. Open the corresponding volume in read-write mode.
68	*/
69	vol->gluebi_desc = ubi_open_volume(vol->ubi->ubi_num, vol->vol_id,
70	UBI_READWRITE);
71	if (IS_ERR(vol->gluebi_desc))
72	return PTR_ERR(vol->gluebi_desc);
73	vol->gluebi_refcount += 1;
74	return 0;
75	}
76
77	/**
78	* gluebi_put_device - put MTD device reference.
79	* @mtd: the MTD device description object
80	*
81	* This function is called every time the MTD device is being put. Returns
82	* zero in case of success and a negative error code in case of failure.
83	*/
84	static void gluebi_put_device(struct mtd_info *mtd)
85	{
86	struct ubi_volume *vol;
87
88	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
89	vol->gluebi_refcount -= 1;
90	ubi_assert(vol->gluebi_refcount >= 0);
91	if (vol->gluebi_refcount == 0)
92	ubi_close_volume(vol->gluebi_desc);
93	}
94
95	/**
96	* gluebi_read - read operation of emulated MTD devices.
97	* @mtd: MTD device description object
98	* @from: absolute offset from where to read
99	* @len: how many bytes to read
100	* @retlen: count of read bytes is returned here
101	* @buf: buffer to store the read data
102	*
103	* This function returns zero in case of success and a negative error code in
104	* case of failure.
105	*/
106	static int gluebi_read(struct mtd_info *mtd, loff_t from, size_t len,
107	size_t retlen, unsigned char buf)
108	{
109	int err = 0, lnum, offs, total_read;
110	struct ubi_volume *vol;
111	struct ubi_device *ubi;
112	uint64_t tmp = from;
113
c8566350	114	dbg_gen("read %zd bytes from offset %lld", len, from);
801c135c AB	115
	116	if (len < 0 \|\| from < 0 \|\| from + len > mtd->size)
	117	return -EINVAL;
	118
	119	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
	120	ubi = vol->ubi;
	121
	122	offs = do_div(tmp, mtd->erasesize);
	123	lnum = tmp;
	124
	125	total_read = len;
	126	while (total_read) {
	127	size_t to_read = mtd->erasesize - offs;
	128
	129	if (to_read > total_read)
	130	to_read = total_read;
	131
89b96b69	132	err = ubi_eba_read_leb(ubi, vol, lnum, buf, offs, to_read, 0);
801c135c AB	133	if (err)
	134	break;
	135
	136	lnum += 1;
	137	offs = 0;
	138	total_read -= to_read;
	139	buf += to_read;
	140	}
	141
	142	*retlen = len - total_read;
	143	return err;
	144	}
	145
	146	/**
	147	* gluebi_write - write operation of emulated MTD devices.
	148	* @mtd: MTD device description object
	149	* @to: absolute offset where to write
	150	* @len: how many bytes to write
	151	* @retlen: count of written bytes is returned here
	152	* @buf: buffer with data to write
	153	*
	154	* This function returns zero in case of success and a negative error code in
	155	* case of failure.
	156	*/
	157	static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
	158	size_t retlen, const u_char buf)
	159	{
	160	int err = 0, lnum, offs, total_written;
	161	struct ubi_volume *vol;
	162	struct ubi_device *ubi;
	163	uint64_t tmp = to;
	164
c8566350	165	dbg_gen("write %zd bytes to offset %lld", len, to);
801c135c AB	166
	167	if (len < 0 \|\| to < 0 \|\| len + to > mtd->size)
	168	return -EINVAL;
	169
	170	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
	171	ubi = vol->ubi;
	172
	173	if (ubi->ro_mode)
	174	return -EROFS;
	175
	176	offs = do_div(tmp, mtd->erasesize);
	177	lnum = tmp;
	178
	179	if (len % mtd->writesize \|\| offs % mtd->writesize)
	180	return -EINVAL;
	181
	182	total_written = len;
	183	while (total_written) {
	184	size_t to_write = mtd->erasesize - offs;
	185
	186	if (to_write > total_written)
	187	to_write = total_written;
	188
89b96b69 AB	189	err = ubi_eba_write_leb(ubi, vol, lnum, buf, offs, to_write,
89b96b69 AB	190	UBI_UNKNOWN);
801c135c AB	191	if (err)
	192	break;
	193
	194	lnum += 1;
	195	offs = 0;
	196	total_written -= to_write;
	197	buf += to_write;
	198	}
	199
	200	*retlen = len - total_written;
	201	return err;
	202	}
	203
	204	/**
	205	* gluebi_erase - erase operation of emulated MTD devices.
	206	* @mtd: the MTD device description object
	207	* @instr: the erase operation description
	208	*
	209	* This function calls the erase callback when finishes. Returns zero in case
	210	* of success and a negative error code in case of failure.
	211	*/
	212	static int gluebi_erase(struct mtd_info mtd, struct erase_info instr)
	213	{
	214	int err, i, lnum, count;
	215	struct ubi_volume *vol;
	216	struct ubi_device *ubi;
	217
c8566350	218	dbg_gen("erase %u bytes at offset %u", instr->len, instr->addr);
801c135c AB	219
	220	if (instr->addr < 0 \|\| instr->addr > mtd->size - mtd->erasesize)
	221	return -EINVAL;
	222
	223	if (instr->len < 0 \|\| instr->addr + instr->len > mtd->size)
	224	return -EINVAL;
	225
	226	if (instr->addr % mtd->writesize \|\| instr->len % mtd->writesize)
	227	return -EINVAL;
	228
	229	lnum = instr->addr / mtd->erasesize;
	230	count = instr->len / mtd->erasesize;
	231
	232	vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
	233	ubi = vol->ubi;
	234
	235	if (ubi->ro_mode)
	236	return -EROFS;
	237
	238	for (i = 0; i < count; i++) {
89b96b69	239	err = ubi_eba_unmap_leb(ubi, vol, lnum + i);
801c135c AB	240	if (err)
	241	goto out_err;
	242	}
	243
	244	/*
	245	* MTD erase operations are synchronous, so we have to make sure the
	246	* physical eraseblock is wiped out.
	247	*/
	248	err = ubi_wl_flush(ubi);
	249	if (err)
	250	goto out_err;
	251
9c9ec147 AB	252	instr->state = MTD_ERASE_DONE;
9c9ec147 AB	253	mtd_erase_callback(instr);
801c135c AB	254	return 0;
	255
	256	out_err:
	257	instr->state = MTD_ERASE_FAILED;
	258	instr->fail_addr = lnum * mtd->erasesize;
	259	return err;
	260	}
	261
	262	/**
	263	* ubi_create_gluebi - initialize gluebi for an UBI volume.
	264	* @ubi: UBI device description object
	265	* @vol: volume description object
	266	*
	267	* This function is called when an UBI volume is created in order to create
	268	* corresponding fake MTD device. Returns zero in case of success and a
	269	* negative error code in case of failure.
	270	*/
	271	int ubi_create_gluebi(struct ubi_device ubi, struct ubi_volume vol)
	272	{
801c135c AB	273	struct mtd_info *mtd = &vol->gluebi_mtd;
	274
	275	mtd->name = kmemdup(vol->name, vol->name_len + 1, GFP_KERNEL);
	276	if (!mtd->name)
	277	return -ENOMEM;
	278
	279	mtd->type = MTD_UBIVOLUME;
	280	if (!ubi->ro_mode)
	281	mtd->flags = MTD_WRITEABLE;
	282	mtd->writesize = ubi->min_io_size;
	283	mtd->owner = THIS_MODULE;
801c135c AB	284	mtd->erasesize = vol->usable_leb_size;
	285	mtd->read = gluebi_read;
	286	mtd->write = gluebi_write;
	287	mtd->erase = gluebi_erase;
	288	mtd->get_device = gluebi_get_device;
	289	mtd->put_device = gluebi_put_device;
	290
941dfb07 AB	291	/*
	292	* In case of dynamic volume, MTD device size is just volume size. In
	293	* case of a static volume the size is equivalent to the amount of data
cbd8a9d2	294	* bytes.
941dfb07 AB	295	*/
	296	if (vol->vol_type == UBI_DYNAMIC_VOLUME)
	297	mtd->size = vol->usable_leb_size * vol->reserved_pebs;
cbd8a9d2 JA	298	else
cbd8a9d2 JA	299	mtd->size = vol->used_bytes;
941dfb07	300
801c135c	301	if (add_mtd_device(mtd)) {
bb84c1a1	302	ubi_err("cannot not add MTD device");
801c135c AB	303	kfree(mtd->name);
	304	return -ENFILE;
	305	}
	306
c8566350	307	dbg_gen("added mtd%d (\"%s\"), size %u, EB size %u",
801c135c AB	308	mtd->index, mtd->name, mtd->size, mtd->erasesize);
	309	return 0;
	310	}
	311
	312	/**
	313	* ubi_destroy_gluebi - close gluebi for an UBI volume.
	314	* @vol: volume description object
	315	*
	316	* This function is called when an UBI volume is removed in order to remove
	317	* corresponding fake MTD device. Returns zero in case of success and a
	318	* negative error code in case of failure.
	319	*/
	320	int ubi_destroy_gluebi(struct ubi_volume *vol)
	321	{
	322	int err;
	323	struct mtd_info *mtd = &vol->gluebi_mtd;
	324
c8566350	325	dbg_gen("remove mtd%d", mtd->index);
801c135c AB	326	err = del_mtd_device(mtd);
	327	if (err)
	328	return err;
	329	kfree(mtd->name);
	330	return 0;
	331	}
941dfb07 AB	332
	333	/**
	334	* ubi_gluebi_updated - UBI volume was updated notifier.
	335	* @vol: volume description object
	336	*
	337	* This function is called every time an UBI volume is updated. This function
	338	* does nothing if volume @vol is dynamic, and changes MTD device size if the
	339	* volume is static. This is needed because static volumes cannot be read past
	340	* data they contain.
	341	*/
	342	void ubi_gluebi_updated(struct ubi_volume *vol)
	343	{
	344	struct mtd_info *mtd = &vol->gluebi_mtd;
	345
	346	if (vol->vol_type == UBI_STATIC_VOLUME)
	347	mtd->size = vol->used_bytes;
	348	}