drivers/mtd/ubi/gluebi.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  * 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_msg("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->vol_id, 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_msg("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->vol_id, 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_msg("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->vol_id, 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)
 {
 	int err;
 	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->size       = vol->usable_leb_size * vol->reserved_pebs;
 	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;

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

 	dbg_msg("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_msg("remove mtd%d", mtd->index);
 	err = del_mtd_device(mtd);
 	if (err)
 		return err;
 	kfree(mtd->name);
 	return 0;
 }
	/*
	* 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_msg("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->vol_id, 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_msg("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->vol_id, 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_msg("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->vol_id, 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)
	{
	int err;
	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->size = vol->usable_leb_size * vol->reserved_pebs;
	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;

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

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