diff options
Diffstat (limited to 'drivers/mtd/ubi/kapi.c')
| -rw-r--r-- | drivers/mtd/ubi/kapi.c | 575 |
1 files changed, 575 insertions, 0 deletions
diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c new file mode 100644 index 000000000000..d352c4575c3d --- /dev/null +++ b/drivers/mtd/ubi/kapi.c @@ -0,0 +1,575 @@ +/* + * 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) + */ + +/* This file mostly implements UBI kernel API functions */ + +#include <linux/module.h> +#include <linux/err.h> +#include <asm/div64.h> +#include "ubi.h" + +/** + * ubi_get_device_info - get information about UBI device. + * @ubi_num: UBI device number + * @di: the information is stored here + * + * This function returns %0 in case of success and a %-ENODEV if there is no + * such UBI device. + */ +int ubi_get_device_info(int ubi_num, struct ubi_device_info *di) +{ + const struct ubi_device *ubi; + + if (!try_module_get(THIS_MODULE)) + return -ENODEV; + + if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES || + !ubi_devices[ubi_num]) { + module_put(THIS_MODULE); + return -ENODEV; + } + + ubi = ubi_devices[ubi_num]; + di->ubi_num = ubi->ubi_num; + di->leb_size = ubi->leb_size; + di->min_io_size = ubi->min_io_size; + di->ro_mode = ubi->ro_mode; + di->cdev = MKDEV(ubi->major, 0); + module_put(THIS_MODULE); + return 0; +} +EXPORT_SYMBOL_GPL(ubi_get_device_info); + +/** + * ubi_get_volume_info - get information about UBI volume. + * @desc: volume descriptor + * @vi: the information is stored here + */ +void ubi_get_volume_info(struct ubi_volume_desc *desc, + struct ubi_volume_info *vi) +{ + const struct ubi_volume *vol = desc->vol; + const struct ubi_device *ubi = vol->ubi; + + vi->vol_id = vol->vol_id; + vi->ubi_num = ubi->ubi_num; + vi->size = vol->reserved_pebs; + vi->used_bytes = vol->used_bytes; + vi->vol_type = vol->vol_type; + vi->corrupted = vol->corrupted; + vi->upd_marker = vol->upd_marker; + vi->alignment = vol->alignment; + vi->usable_leb_size = vol->usable_leb_size; + vi->name_len = vol->name_len; + vi->name = vol->name; + vi->cdev = MKDEV(ubi->major, vi->vol_id + 1); +} +EXPORT_SYMBOL_GPL(ubi_get_volume_info); + +/** + * ubi_open_volume - open UBI volume. + * @ubi_num: UBI device number + * @vol_id: volume ID + * @mode: open mode + * + * The @mode parameter specifies if the volume should be opened in read-only + * mode, read-write mode, or exclusive mode. The exclusive mode guarantees that + * nobody else will be able to open this volume. UBI allows to have many volume + * readers and one writer at a time. + * + * If a static volume is being opened for the first time since boot, it will be + * checked by this function, which means it will be fully read and the CRC + * checksum of each logical eraseblock will be checked. + * + * This function returns volume descriptor in case of success and a negative + * error code in case of failure. + */ +struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode) +{ + int err; + struct ubi_volume_desc *desc; + struct ubi_device *ubi = ubi_devices[ubi_num]; + struct ubi_volume *vol; + + dbg_msg("open device %d volume %d, mode %d", ubi_num, vol_id, mode); + + err = -ENODEV; + if (!try_module_get(THIS_MODULE)) + return ERR_PTR(err); + + if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES || !ubi) + goto out_put; + + err = -EINVAL; + if (vol_id < 0 || vol_id >= ubi->vtbl_slots) + goto out_put; + if (mode != UBI_READONLY && mode != UBI_READWRITE && + mode != UBI_EXCLUSIVE) + goto out_put; + + desc = kmalloc(sizeof(struct ubi_volume_desc), GFP_KERNEL); + if (!desc) { + err = -ENOMEM; + goto out_put; + } + + spin_lock(&ubi->volumes_lock); + vol = ubi->volumes[vol_id]; + if (!vol) { + err = -ENODEV; + goto out_unlock; + } + + err = -EBUSY; + switch (mode) { + case UBI_READONLY: + if (vol->exclusive) + goto out_unlock; + vol->readers += 1; + break; + + case UBI_READWRITE: + if (vol->exclusive || vol->writers > 0) + goto out_unlock; + vol->writers += 1; + break; + + case UBI_EXCLUSIVE: + if (vol->exclusive || vol->writers || vol->readers) + goto out_unlock; + vol->exclusive = 1; + break; + } + spin_unlock(&ubi->volumes_lock); + + desc->vol = vol; + desc->mode = mode; + + /* + * To prevent simultaneous checks of the same volume we use @vtbl_mutex, + * although it is not the purpose it was introduced for. + */ + mutex_lock(&ubi->vtbl_mutex); + if (!vol->checked) { + /* This is the first open - check the volume */ + err = ubi_check_volume(ubi, vol_id); + if (err < 0) { + mutex_unlock(&ubi->vtbl_mutex); + ubi_close_volume(desc); + return ERR_PTR(err); + } + if (err == 1) { + ubi_warn("volume %d on UBI device %d is corrupted", + vol_id, ubi->ubi_num); + vol->corrupted = 1; + } + vol->checked = 1; + } + mutex_unlock(&ubi->vtbl_mutex); + return desc; + +out_unlock: + spin_unlock(&ubi->volumes_lock); + kfree(desc); +out_put: + module_put(THIS_MODULE); + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(ubi_open_volume); + +/** + * ubi_open_volume_nm - open UBI volume by name. + * @ubi_num: UBI device number + * @name: volume name + * @mode: open mode + * + * This function is similar to 'ubi_open_volume()', but opens a volume by name. + */ +struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name, + int mode) +{ + int i, vol_id = -1, len; + struct ubi_volume_desc *ret; + struct ubi_device *ubi; + + dbg_msg("open volume %s, mode %d", name, mode); + + if (!name) + return ERR_PTR(-EINVAL); + + len = strnlen(name, UBI_VOL_NAME_MAX + 1); + if (len > UBI_VOL_NAME_MAX) + return ERR_PTR(-EINVAL); + + ret = ERR_PTR(-ENODEV); + if (!try_module_get(THIS_MODULE)) + return ret; + + if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES || !ubi_devices[ubi_num]) + goto out_put; + + ubi = ubi_devices[ubi_num]; + + spin_lock(&ubi->volumes_lock); + /* Walk all volumes of this UBI device */ + for (i = 0; i < ubi->vtbl_slots; i++) { + struct ubi_volume *vol = ubi->volumes[i]; + + if (vol && len == vol->name_len && !strcmp(name, vol->name)) { + vol_id = i; + break; + } + } + spin_unlock(&ubi->volumes_lock); + + if (vol_id < 0) + goto out_put; + + ret = ubi_open_volume(ubi_num, vol_id, mode); + +out_put: + module_put(THIS_MODULE); + return ret; +} +EXPORT_SYMBOL_GPL(ubi_open_volume_nm); + +/** + * ubi_close_volume - close UBI volume. + * @desc: volume descriptor + */ +void ubi_close_volume(struct ubi_volume_desc *desc) +{ + struct ubi_volume *vol = desc->vol; + + dbg_msg("close volume %d, mode %d", vol->vol_id, desc->mode); + + spin_lock(&vol->ubi->volumes_lock); + switch (desc->mode) { + case UBI_READONLY: + vol->readers -= 1; + break; + case UBI_READWRITE: + vol->writers -= 1; + break; + case UBI_EXCLUSIVE: + vol->exclusive = 0; + } + spin_unlock(&vol->ubi->volumes_lock); + + kfree(desc); + module_put(THIS_MODULE); +} +EXPORT_SYMBOL_GPL(ubi_close_volume); + +/** + * ubi_leb_read - read data. + * @desc: volume descriptor + * @lnum: logical eraseblock number to read from + * @buf: buffer where to store the read data + * @offset: offset within the logical eraseblock to read from + * @len: how many bytes to read + * @check: whether UBI has to check the read data's CRC or not. + * + * This function reads data from offset @offset of logical eraseblock @lnum and + * stores the data at @buf. When reading from static volumes, @check specifies + * whether the data has to be checked or not. If yes, the whole logical + * eraseblock will be read and its CRC checksum will be checked (i.e., the CRC + * checksum is per-eraseblock). So checking may substantially slow down the + * read speed. The @check argument is ignored for dynamic volumes. + * + * In case of success, this function returns zero. In case of failure, this + * function returns a negative error code. + * + * %-EBADMSG error code is returned: + * o for both static and dynamic volumes if MTD driver has detected a data + * integrity problem (unrecoverable ECC checksum mismatch in case of NAND); + * o for static volumes in case of data CRC mismatch. + * + * If the volume is damaged because of an interrupted update this function just + * returns immediately with %-EBADF error code. + */ +int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset, + int len, int check) +{ + struct ubi_volume *vol = desc->vol; + struct ubi_device *ubi = vol->ubi; + int err, vol_id = vol->vol_id; + + dbg_msg("read %d bytes from LEB %d:%d:%d", len, vol_id, lnum, offset); + + if (vol_id < 0 || vol_id >= ubi->vtbl_slots || lnum < 0 || + lnum >= vol->used_ebs || offset < 0 || len < 0 || + offset + len > vol->usable_leb_size) + return -EINVAL; + + if (vol->vol_type == UBI_STATIC_VOLUME && lnum == vol->used_ebs - 1 && + offset + len > vol->last_eb_bytes) + return -EINVAL; + + if (vol->upd_marker) + return -EBADF; + if (len == 0) + return 0; + + err = ubi_eba_read_leb(ubi, vol_id, lnum, buf, offset, len, check); + if (err && err == -EBADMSG && vol->vol_type == UBI_STATIC_VOLUME) { + ubi_warn("mark volume %d as corrupted", vol_id); + vol->corrupted = 1; + } + + return err; +} +EXPORT_SYMBOL_GPL(ubi_leb_read); + +/** + * ubi_leb_write - write data. + * @desc: volume descriptor + * @lnum: logical eraseblock number to write to + * @buf: data to write + * @offset: offset within the logical eraseblock where to write + * @len: how many bytes to write + * @dtype: expected data type + * + * This function writes @len bytes of data from @buf to offset @offset of + * logical eraseblock @lnum. The @dtype argument describes expected lifetime of + * the data. + * + * This function takes care of physical eraseblock write failures. If write to + * the physical eraseblock write operation fails, the logical eraseblock is + * re-mapped to another physical eraseblock, the data is recovered, and the + * write finishes. UBI has a pool of reserved physical eraseblocks for this. + * + * If all the data were successfully written, zero is returned. If an error + * occurred and UBI has not been able to recover from it, this function returns + * a negative error code. Note, in case of an error, it is possible that + * something was still written to the flash media, but that may be some + * garbage. + * + * If the volume is damaged because of an interrupted update this function just + * returns immediately with %-EBADF code. + */ +int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf, + int offset, int len, int dtype) +{ + struct ubi_volume *vol = desc->vol; + struct ubi_device *ubi = vol->ubi; + int vol_id = vol->vol_id; + + dbg_msg("write %d bytes to LEB %d:%d:%d", len, vol_id, lnum, offset); + + if (vol_id < 0 || vol_id >= ubi->vtbl_slots) + return -EINVAL; + + if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME) + return -EROFS; + + if (lnum < 0 || lnum >= vol->reserved_pebs || offset < 0 || len < 0 || + offset + len > vol->usable_leb_size || offset % ubi->min_io_size || + len % ubi->min_io_size) + return -EINVAL; + + if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM && + dtype != UBI_UNKNOWN) + return -EINVAL; + + if (vol->upd_marker) + return -EBADF; + + if (len == 0) + return 0; + + return ubi_eba_write_leb(ubi, vol_id, lnum, buf, offset, len, dtype); +} +EXPORT_SYMBOL_GPL(ubi_leb_write); + +/* + * ubi_leb_change - change logical eraseblock atomically. + * @desc: volume descriptor + * @lnum: logical eraseblock number to change + * @buf: data to write + * @len: how many bytes to write + * @dtype: expected data type + * + * This function changes the contents of a logical eraseblock atomically. @buf + * has to contain new logical eraseblock data, and @len - the length of the + * data, which has to be aligned. The length may be shorter then the logical + * eraseblock size, ant the logical eraseblock may be appended to more times + * later on. This function guarantees that in case of an unclean reboot the old + * contents is preserved. Returns zero in case of success and a negative error + * code in case of failure. + */ +int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf, + int len, int dtype) +{ + struct ubi_volume *vol = desc->vol; + struct ubi_device *ubi = vol->ubi; + int vol_id = vol->vol_id; + + dbg_msg("atomically write %d bytes to LEB %d:%d", len, vol_id, lnum); + + if (vol_id < 0 || vol_id >= ubi->vtbl_slots) + return -EINVAL; + + if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME) + return -EROFS; + + if (lnum < 0 || lnum >= vol->reserved_pebs || len < 0 || + len > vol->usable_leb_size || len % ubi->min_io_size) + return -EINVAL; + + if (dtype != UBI_LONGTERM && dtype != UBI_SHORTTERM && + dtype != UBI_UNKNOWN) + return -EINVAL; + + if (vol->upd_marker) + return -EBADF; + + if (len == 0) + return 0; + + return ubi_eba_atomic_leb_change(ubi, vol_id, lnum, buf, len, dtype); +} +EXPORT_SYMBOL_GPL(ubi_leb_change); + +/** + * ubi_leb_erase - erase logical eraseblock. + * @desc: volume descriptor + * @lnum: logical eraseblock number + * + * This function un-maps logical eraseblock @lnum and synchronously erases the + * correspondent physical eraseblock. Returns zero in case of success and a + * negative error code in case of failure. + * + * If the volume is damaged because of an interrupted update this function just + * returns immediately with %-EBADF code. + */ +int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum) +{ + struct ubi_volume *vol = desc->vol; + struct ubi_device *ubi = vol->ubi; + int err, vol_id = vol->vol_id; + + dbg_msg("erase LEB %d:%d", vol_id, lnum); + + if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME) + return -EROFS; + + if (lnum < 0 || lnum >= vol->reserved_pebs) + return -EINVAL; + + if (vol->upd_marker) + return -EBADF; + + err = ubi_eba_unmap_leb(ubi, vol_id, lnum); + if (err) + return err; + + return ubi_wl_flush(ubi); +} +EXPORT_SYMBOL_GPL(ubi_leb_erase); + +/** + * ubi_leb_unmap - un-map logical eraseblock. + * @desc: volume descriptor + * @lnum: logical eraseblock number + * + * This function un-maps logical eraseblock @lnum and schedules the + * corresponding physical eraseblock for erasure, so that it will eventually be + * physically erased in background. This operation is much faster then the + * erase operation. + * + * Unlike erase, the un-map operation does not guarantee that the logical + * eraseblock will contain all 0xFF bytes when UBI is initialized again. For + * example, if several logical eraseblocks are un-mapped, and an unclean reboot + * happens after this, the logical eraseblocks will not necessarily be + * un-mapped again when this MTD device is attached. They may actually be + * mapped to the same physical eraseblocks again. So, this function has to be + * used with care. + * + * In other words, when un-mapping a logical eraseblock, UBI does not store + * any information about this on the flash media, it just marks the logical + * eraseblock as "un-mapped" in RAM. If UBI is detached before the physical + * eraseblock is physically erased, it will be mapped again to the same logical + * eraseblock when the MTD device is attached again. + * + * The main and obvious use-case of this function is when the contents of a + * logical eraseblock has to be re-written. Then it is much more efficient to + * first un-map it, then write new data, rather then first erase it, then write + * new data. Note, once new data has been written to the logical eraseblock, + * UBI guarantees that the old contents has gone forever. In other words, if an + * unclean reboot happens after the logical eraseblock has been un-mapped and + * then written to, it will contain the last written data. + * + * This function returns zero in case of success and a negative error code in + * case of failure. If the volume is damaged because of an interrupted update + * this function just returns immediately with %-EBADF code. + */ +int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum) +{ + struct ubi_volume *vol = desc->vol; + struct ubi_device *ubi = vol->ubi; + int vol_id = vol->vol_id; + + dbg_msg("unmap LEB %d:%d", vol_id, lnum); + + if (desc->mode == UBI_READONLY || vol->vol_type == UBI_STATIC_VOLUME) + return -EROFS; + + if (lnum < 0 || lnum >= vol->reserved_pebs) + return -EINVAL; + + if (vol->upd_marker) + return -EBADF; + + return ubi_eba_unmap_leb(ubi, vol_id, lnum); +} +EXPORT_SYMBOL_GPL(ubi_leb_unmap); + +/** + * ubi_is_mapped - check if logical eraseblock is mapped. + * @desc: volume descriptor + * @lnum: logical eraseblock number + * + * This function checks if logical eraseblock @lnum is mapped to a physical + * eraseblock. If a logical eraseblock is un-mapped, this does not necessarily + * mean it will still be un-mapped after the UBI device is re-attached. The + * logical eraseblock may become mapped to the physical eraseblock it was last + * mapped to. + * + * This function returns %1 if the LEB is mapped, %0 if not, and a negative + * error code in case of failure. If the volume is damaged because of an + * interrupted update this function just returns immediately with %-EBADF error + * code. + */ +int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum) +{ + struct ubi_volume *vol = desc->vol; + + dbg_msg("test LEB %d:%d", vol->vol_id, lnum); + + if (lnum < 0 || lnum >= vol->reserved_pebs) + return -EINVAL; + + if (vol->upd_marker) + return -EBADF; + + return vol->eba_tbl[lnum] >= 0; +} +EXPORT_SYMBOL_GPL(ubi_is_mapped); |