u-boot/drivers/mtd/mtdcore.c

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/*
* Core registration and callback routines for MTD
* drivers and users.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/mtd/mtd.h>
#include <linux/compat.h>
#include <ubi_uboot.h>
struct mtd_info *mtd_table[MAX_MTD_DEVICES];
int add_mtd_device(struct mtd_info *mtd)
{
int i;
BUG_ON(mtd->writesize == 0);
for (i = 0; i < MAX_MTD_DEVICES; i++)
if (!mtd_table[i]) {
mtd_table[i] = mtd;
mtd->index = i;
mtd->usecount = 0;
/* default value if not set by driver */
if (mtd->bitflip_threshold == 0)
mtd->bitflip_threshold = mtd->ecc_strength;
/* No need to get a refcount on the module containing
the notifier, since we hold the mtd_table_mutex */
/* We _know_ we aren't being removed, because
our caller is still holding us here. So none
of this try_ nonsense, and no bitching about it
either. :) */
return 0;
}
return 1;
}
/**
* del_mtd_device - unregister an MTD device
* @mtd: pointer to MTD device info structure
*
* Remove a device from the list of MTD devices present in the system,
* and notify each currently active MTD 'user' of its departure.
* Returns zero on success or 1 on failure, which currently will happen
* if the requested device does not appear to be present in the list.
*/
int del_mtd_device(struct mtd_info *mtd)
{
int ret;
if (mtd_table[mtd->index] != mtd) {
ret = -ENODEV;
} else if (mtd->usecount) {
printk(KERN_NOTICE "Removing MTD device #%d (%s)"
" with use count %d\n",
mtd->index, mtd->name, mtd->usecount);
ret = -EBUSY;
} else {
/* No need to get a refcount on the module containing
* the notifier, since we hold the mtd_table_mutex */
mtd_table[mtd->index] = NULL;
ret = 0;
}
return ret;
}
/**
* get_mtd_device - obtain a validated handle for an MTD device
* @mtd: last known address of the required MTD device
* @num: internal device number of the required MTD device
*
* Given a number and NULL address, return the num'th entry in the device
* table, if any. Given an address and num == -1, search the device table
* for a device with that address and return if it's still present. Given
* both, return the num'th driver only if its address matches. Return
* error code if not.
*/
struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num)
{
struct mtd_info *ret = NULL;
int i, err = -ENODEV;
if (num == -1) {
for (i = 0; i < MAX_MTD_DEVICES; i++)
if (mtd_table[i] == mtd)
ret = mtd_table[i];
} else if (num < MAX_MTD_DEVICES) {
ret = mtd_table[num];
if (mtd && mtd != ret)
ret = NULL;
}
if (!ret)
goto out_unlock;
ret->usecount++;
return ret;
out_unlock:
return ERR_PTR(err);
}
/**
* get_mtd_device_nm - obtain a validated handle for an MTD device by
* device name
* @name: MTD device name to open
*
* This function returns MTD device description structure in case of
* success and an error code in case of failure.
*/
struct mtd_info *get_mtd_device_nm(const char *name)
{
int i, err = -ENODEV;
struct mtd_info *mtd = NULL;
for (i = 0; i < MAX_MTD_DEVICES; i++) {
if (mtd_table[i] && !strcmp(name, mtd_table[i]->name)) {
mtd = mtd_table[i];
break;
}
}
if (!mtd)
goto out_unlock;
mtd->usecount++;
return mtd;
out_unlock:
return ERR_PTR(err);
}
void put_mtd_device(struct mtd_info *mtd)
{
int c;
c = --mtd->usecount;
BUG_ON(c < 0);
}
#if defined(CONFIG_CMD_MTDPARTS_SPREAD)
/**
* mtd_get_len_incl_bad
*
* Check if length including bad blocks fits into device.
*
* @param mtd an MTD device
* @param offset offset in flash
* @param length image length
* @return image length including bad blocks in *len_incl_bad and whether or not
* the length returned was truncated in *truncated
*/
void mtd_get_len_incl_bad(struct mtd_info *mtd, uint64_t offset,
const uint64_t length, uint64_t *len_incl_bad,
int *truncated)
{
*truncated = 0;
*len_incl_bad = 0;
if (!mtd->block_isbad) {
*len_incl_bad = length;
return;
}
uint64_t len_excl_bad = 0;
uint64_t block_len;
while (len_excl_bad < length) {
if (offset >= mtd->size) {
*truncated = 1;
return;
}
block_len = mtd->erasesize - (offset & (mtd->erasesize - 1));
if (!mtd->block_isbad(mtd, offset & ~(mtd->erasesize - 1)))
len_excl_bad += block_len;
*len_incl_bad += block_len;
offset += block_len;
}
}
#endif /* defined(CONFIG_CMD_MTDPARTS_SPREAD) */
/*
* Erase is an asynchronous operation. Device drivers are supposed
* to call instr->callback() whenever the operation completes, even
* if it completes with a failure.
* Callers are supposed to pass a callback function and wait for it
* to be called before writing to the block.
*/
int mtd_erase(struct mtd_info *mtd, struct erase_info *instr)
{
if (instr->addr > mtd->size || instr->len > mtd->size - instr->addr)
return -EINVAL;
if (!(mtd->flags & MTD_WRITEABLE))
return -EROFS;
instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
if (!instr->len) {
instr->state = MTD_ERASE_DONE;
mtd_erase_callback(instr);
return 0;
}
return mtd->_erase(mtd, instr);
}
int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
u_char *buf)
{
mtd: driver _read() returns max_bitflips; mtd_read() returns -EUCLEAN Linux modified the MTD driver interface in commit edbc4540 (with the same name as this commit). The effect is that calls to mtd_read will not return -EUCLEAN if the number of ECC-corrected bit errors is below a certain threshold, which defaults to the strength of the ECC. This allows -EUCLEAN to stop indicating "some bits were corrected" and begin indicating "a large number of bits were corrected, the data held in this region of flash may be lost soon". UBI makes use of this and when -EUCLEAN is returned from mtd_read it will move data to another block of flash. Without adopting this interface change UBI on U-boot attempts to move data between blocks every time a single bit is corrected using the ECC, which is a very common occurance on some devices. For some devices where bit errors are common enough, UBI can get stuck constantly moving data around because each block it attempts to use has a single bit error. This condition is hit when wear_leveling_worker attempts to move data from one PEB to another in response to an -EUCLEAN/UBI_IO_BITFLIPS error. When this happens ubi_eba_copy_leb is called to perform the data copy, and after the data is written it is read back to check its validity. If that read returns UBI_IO_BITFLIPS (in response to an MTD -EUCLEAN) then ubi_eba_copy_leb returns 1 to wear_leveling worker, which then proceeds to schedule the destination PEB for erasure. This leads to erase_worker running on the PEB, and following a successful erase wear_leveling_worker is called which begins this whole cycle all over again. The end result is that (without UBI debug output enabled) the boot appears to simply hang whilst in reality U-boot busily works away at destroying a block of the NAND flash. Debug output from this situation: UBI DBG: ensure_wear_leveling: schedule scrubbing UBI DBG: wear_leveling_worker: scrub PEB 1027 to PEB 4083 UBI DBG: ubi_io_read_vid_hdr: read VID header from PEB 1027 UBI DBG: ubi_io_read: read 4096 bytes from PEB 1027:4096 UBI DBG: ubi_eba_copy_leb: copy LEB 0:0, PEB 1027 to PEB 4083 UBI DBG: ubi_eba_copy_leb: read 1040384 bytes of data UBI DBG: ubi_io_read: read 1040384 bytes from PEB 1027:8192 UBI: fixable bit-flip detected at PEB 1027 UBI DBG: ubi_io_write_vid_hdr: write VID header to PEB 4083 UBI DBG: ubi_io_write: write 4096 bytes to PEB 4083:4096 UBI DBG: ubi_io_read_vid_hdr: read VID header from PEB 4083 UBI DBG: ubi_io_read: read 4096 bytes from PEB 4083:4096 UBI DBG: ubi_io_write: write 4096 bytes to PEB 4083:8192 UBI DBG: ubi_io_read: read 4096 bytes from PEB 4083:8192 UBI: fixable bit-flip detected at PEB 4083 UBI DBG: schedule_erase: schedule erasure of PEB 4083, EC 55, torture 0 UBI DBG: erase_worker: erase PEB 4083 EC 55 UBI DBG: sync_erase: erase PEB 4083, old EC 55 UBI DBG: do_sync_erase: erase PEB 4083 UBI DBG: sync_erase: erased PEB 4083, new EC 56 UBI DBG: ubi_io_write_ec_hdr: write EC header to PEB 4083 UBI DBG: ubi_io_write: write 4096 bytes to PEB 4083:0 UBI DBG: ensure_wear_leveling: schedule scrubbing UBI DBG: wear_leveling_worker: scrub PEB 1027 to PEB 4083 ... This patch adopts the interface change as in Linux commit edbc4540 in order to avoid such situations. Given that none of the drivers under drivers/mtd return -EUCLEAN, this should only affect those using software ECC. I have tested that it works on a board which is currently out of tree, but which I hope to be able to begin upstreaming soon. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Acked-by: Stefan Roese <sr@denx.de>
2013-09-04 14:16:56 +00:00
int ret_code;
if (from < 0 || from > mtd->size || len > mtd->size - from)
return -EINVAL;
if (!len)
return 0;
mtd: driver _read() returns max_bitflips; mtd_read() returns -EUCLEAN Linux modified the MTD driver interface in commit edbc4540 (with the same name as this commit). The effect is that calls to mtd_read will not return -EUCLEAN if the number of ECC-corrected bit errors is below a certain threshold, which defaults to the strength of the ECC. This allows -EUCLEAN to stop indicating "some bits were corrected" and begin indicating "a large number of bits were corrected, the data held in this region of flash may be lost soon". UBI makes use of this and when -EUCLEAN is returned from mtd_read it will move data to another block of flash. Without adopting this interface change UBI on U-boot attempts to move data between blocks every time a single bit is corrected using the ECC, which is a very common occurance on some devices. For some devices where bit errors are common enough, UBI can get stuck constantly moving data around because each block it attempts to use has a single bit error. This condition is hit when wear_leveling_worker attempts to move data from one PEB to another in response to an -EUCLEAN/UBI_IO_BITFLIPS error. When this happens ubi_eba_copy_leb is called to perform the data copy, and after the data is written it is read back to check its validity. If that read returns UBI_IO_BITFLIPS (in response to an MTD -EUCLEAN) then ubi_eba_copy_leb returns 1 to wear_leveling worker, which then proceeds to schedule the destination PEB for erasure. This leads to erase_worker running on the PEB, and following a successful erase wear_leveling_worker is called which begins this whole cycle all over again. The end result is that (without UBI debug output enabled) the boot appears to simply hang whilst in reality U-boot busily works away at destroying a block of the NAND flash. Debug output from this situation: UBI DBG: ensure_wear_leveling: schedule scrubbing UBI DBG: wear_leveling_worker: scrub PEB 1027 to PEB 4083 UBI DBG: ubi_io_read_vid_hdr: read VID header from PEB 1027 UBI DBG: ubi_io_read: read 4096 bytes from PEB 1027:4096 UBI DBG: ubi_eba_copy_leb: copy LEB 0:0, PEB 1027 to PEB 4083 UBI DBG: ubi_eba_copy_leb: read 1040384 bytes of data UBI DBG: ubi_io_read: read 1040384 bytes from PEB 1027:8192 UBI: fixable bit-flip detected at PEB 1027 UBI DBG: ubi_io_write_vid_hdr: write VID header to PEB 4083 UBI DBG: ubi_io_write: write 4096 bytes to PEB 4083:4096 UBI DBG: ubi_io_read_vid_hdr: read VID header from PEB 4083 UBI DBG: ubi_io_read: read 4096 bytes from PEB 4083:4096 UBI DBG: ubi_io_write: write 4096 bytes to PEB 4083:8192 UBI DBG: ubi_io_read: read 4096 bytes from PEB 4083:8192 UBI: fixable bit-flip detected at PEB 4083 UBI DBG: schedule_erase: schedule erasure of PEB 4083, EC 55, torture 0 UBI DBG: erase_worker: erase PEB 4083 EC 55 UBI DBG: sync_erase: erase PEB 4083, old EC 55 UBI DBG: do_sync_erase: erase PEB 4083 UBI DBG: sync_erase: erased PEB 4083, new EC 56 UBI DBG: ubi_io_write_ec_hdr: write EC header to PEB 4083 UBI DBG: ubi_io_write: write 4096 bytes to PEB 4083:0 UBI DBG: ensure_wear_leveling: schedule scrubbing UBI DBG: wear_leveling_worker: scrub PEB 1027 to PEB 4083 ... This patch adopts the interface change as in Linux commit edbc4540 in order to avoid such situations. Given that none of the drivers under drivers/mtd return -EUCLEAN, this should only affect those using software ECC. I have tested that it works on a board which is currently out of tree, but which I hope to be able to begin upstreaming soon. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Acked-by: Stefan Roese <sr@denx.de>
2013-09-04 14:16:56 +00:00
/*
* In the absence of an error, drivers return a non-negative integer
* representing the maximum number of bitflips that were corrected on
* any one ecc region (if applicable; zero otherwise).
*/
ret_code = mtd->_read(mtd, from, len, retlen, buf);
if (unlikely(ret_code < 0))
return ret_code;
if (mtd->ecc_strength == 0)
return 0; /* device lacks ecc */
return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
}
int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
const u_char *buf)
{
*retlen = 0;
if (to < 0 || to > mtd->size || len > mtd->size - to)
return -EINVAL;
if (!mtd->_write || !(mtd->flags & MTD_WRITEABLE))
return -EROFS;
if (!len)
return 0;
return mtd->_write(mtd, to, len, retlen, buf);
}
/*
* In blackbox flight recorder like scenarios we want to make successful writes
* in interrupt context. panic_write() is only intended to be called when its
* known the kernel is about to panic and we need the write to succeed. Since
* the kernel is not going to be running for much longer, this function can
* break locks and delay to ensure the write succeeds (but not sleep).
*/
int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
const u_char *buf)
{
*retlen = 0;
if (!mtd->_panic_write)
return -EOPNOTSUPP;
if (to < 0 || to > mtd->size || len > mtd->size - to)
return -EINVAL;
if (!(mtd->flags & MTD_WRITEABLE))
return -EROFS;
if (!len)
return 0;
return mtd->_panic_write(mtd, to, len, retlen, buf);
}
int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
{
ops->retlen = ops->oobretlen = 0;
if (!mtd->_read_oob)
return -EOPNOTSUPP;
return mtd->_read_oob(mtd, from, ops);
}
/*
* Method to access the protection register area, present in some flash
* devices. The user data is one time programmable but the factory data is read
* only.
*/
int mtd_get_fact_prot_info(struct mtd_info *mtd, struct otp_info *buf,
size_t len)
{
if (!mtd->_get_fact_prot_info)
return -EOPNOTSUPP;
if (!len)
return 0;
return mtd->_get_fact_prot_info(mtd, buf, len);
}
int mtd_read_fact_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
*retlen = 0;
if (!mtd->_read_fact_prot_reg)
return -EOPNOTSUPP;
if (!len)
return 0;
return mtd->_read_fact_prot_reg(mtd, from, len, retlen, buf);
}
int mtd_get_user_prot_info(struct mtd_info *mtd, struct otp_info *buf,
size_t len)
{
if (!mtd->_get_user_prot_info)
return -EOPNOTSUPP;
if (!len)
return 0;
return mtd->_get_user_prot_info(mtd, buf, len);
}
int mtd_read_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
*retlen = 0;
if (!mtd->_read_user_prot_reg)
return -EOPNOTSUPP;
if (!len)
return 0;
return mtd->_read_user_prot_reg(mtd, from, len, retlen, buf);
}
int mtd_write_user_prot_reg(struct mtd_info *mtd, loff_t to, size_t len,
size_t *retlen, u_char *buf)
{
*retlen = 0;
if (!mtd->_write_user_prot_reg)
return -EOPNOTSUPP;
if (!len)
return 0;
return mtd->_write_user_prot_reg(mtd, to, len, retlen, buf);
}
int mtd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from, size_t len)
{
if (!mtd->_lock_user_prot_reg)
return -EOPNOTSUPP;
if (!len)
return 0;
return mtd->_lock_user_prot_reg(mtd, from, len);
}
/* Chip-supported device locking */
int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
if (!mtd->_lock)
return -EOPNOTSUPP;
if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
return -EINVAL;
if (!len)
return 0;
return mtd->_lock(mtd, ofs, len);
}
int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
if (!mtd->_unlock)
return -EOPNOTSUPP;
if (ofs < 0 || ofs > mtd->size || len > mtd->size - ofs)
return -EINVAL;
if (!len)
return 0;
return mtd->_unlock(mtd, ofs, len);
}
int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
{
if (!mtd->_block_isbad)
return 0;
if (ofs < 0 || ofs > mtd->size)
return -EINVAL;
return mtd->_block_isbad(mtd, ofs);
}
int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs)
{
if (!mtd->_block_markbad)
return -EOPNOTSUPP;
if (ofs < 0 || ofs > mtd->size)
return -EINVAL;
if (!(mtd->flags & MTD_WRITEABLE))
return -EROFS;
return mtd->_block_markbad(mtd, ofs);
}