diff options
Diffstat (limited to 'drivers/mtd/ubi/gluebi.c')
| -rw-r--r-- | drivers/mtd/ubi/gluebi.c | 324 |
1 files changed, 324 insertions, 0 deletions
diff --git a/drivers/mtd/ubi/gluebi.c b/drivers/mtd/ubi/gluebi.c new file mode 100644 index 00000000000..c8bbfd1e67a --- /dev/null +++ b/drivers/mtd/ubi/gluebi.c @@ -0,0 +1,324 @@ +/* + * 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; +} |