Add a flag to nand_read_skip_bad() such that if true, any trailing pages in an eraseblock whose contents are entirely 0xff will be dropped.
The implementation is via a new drop_ffs() function which is based on the function of the same name from the ubiformat utility by Artem Bityutskiy.
This is as-per the reccomendations of the UBI FAQ. Without this behaviour, UBI images flashed to NAND where either 1) the ECC used does not map all-0xff to 0xff or 2) the number of times a page can be written is limited by the NAND will not be successfully attached after flashing.
Signed-off-by: Ben Gardiner bengardiner@nanometrics.ca CC: Artem Bityutskiy dedekind1@gmail.com
---
This behaviour was found to fix both UBI and JFFS2 images written to cleanly erased NAND partitions on da850evm. --- drivers/mtd/nand/nand_util.c | 29 ++++++++++++++++++++++++++--- include/nand.h | 3 ++- 2 files changed, 28 insertions(+), 4 deletions(-)
diff --git a/drivers/mtd/nand/nand_util.c b/drivers/mtd/nand/nand_util.c index 2bd8758..c9bb930 100644 --- a/drivers/mtd/nand/nand_util.c +++ b/drivers/mtd/nand/nand_util.c @@ -436,6 +436,22 @@ static int check_skip_len(nand_info_t *nand, loff_t offset, size_t length) return ret; }
+static size_t drop_ffs(const nand_info_t *nand, const u_char *buf, + const size_t *len) +{ + size_t i, l = *len; + + for (i = l - 1; i >= 0; i--) + if (((const uint8_t *)buf)[i] != 0xFF) + break; + + /* The resulting length must be aligned to the minimum flash I/O size */ + l = i + 1; + l = (l + nand->writesize - 1) / nand->writesize; + l *= nand->writesize; + return l; +} + /** * nand_write_skip_bad: * @@ -499,7 +515,7 @@ int nand_write_skip_bad(nand_info_t *nand, loff_t offset, size_t *length, return -EINVAL; }
- if (!need_skip) { + if (!need_skip && !(flags & WITH_DROP_FFS)) { rval = nand_write (nand, offset, length, buffer); if (rval == 0) return 0; @@ -512,7 +528,7 @@ int nand_write_skip_bad(nand_info_t *nand, loff_t offset, size_t *length,
while (left_to_write > 0) { size_t block_offset = offset & (nand->erasesize - 1); - size_t write_size; + size_t write_size, truncated_write_size;
WATCHDOG_RESET ();
@@ -558,7 +574,14 @@ int nand_write_skip_bad(nand_info_t *nand, loff_t offset, size_t *length, else #endif { - rval = nand_write (nand, offset, &write_size, p_buffer); + if (flags & WITH_DROP_FFS) + truncated_write_size = drop_ffs(nand, p_buffer, + &write_size); + else + truncated_write_size = write_size; + + rval = nand_write(nand, offset, &truncated_write_size, + p_buffer); offset += write_size; p_buffer += write_size; } diff --git a/include/nand.h b/include/nand.h index 628317a..b58a82d 100644 --- a/include/nand.h +++ b/include/nand.h @@ -115,7 +115,8 @@ typedef struct nand_erase_options nand_erase_options_t; int nand_read_skip_bad(nand_info_t *nand, loff_t offset, size_t *length, u_char *buffer);
-#define WITH_OOB (1 << 0) /* whether write with yaffs format */ +#define WITH_OOB (1 << 0) /* whether write with yaffs format */ +#define WITH_DROP_FFS (1 << 1) /* drop trailing all-0xff pages */
int nand_write_skip_bad(nand_info_t *nand, loff_t offset, size_t *length, u_char *buffer, int flags);