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 [1]
Signed-off-by: Ben Gardiner bengardiner@nanometrics.ca CC: Artem Bityutskiy dedekind1@gmail.com CC: Detlev Zundel dzu@denx.de
[1] http://www.linux-mtd.infradead.org/doc/ubi.html#L_flasher_algo
---
This behaviour was found to fix both UBI and JFFS2 images written to cleanly erased NAND partitions on da850evm.
Changes since v2: * moved the copyright header addition of nand_util to this patch from patch 'cmd_nand: add nand write.trimffs command' * Did not add Detlev's Acked-by because of movement of copyright header Changes since v1: * rebased to HEAD of git://git.denx.de/u-boot-nand-flash.git : ff7b4a0 ("env_nand: zero-initialize variable nand_erase_options") * wrap the new functionality in a CONFIG_CMD_NAND_TRIMFFS ifdef to reduce size impact of new feature --- drivers/mtd/nand/nand_util.c | 35 ++++++++++++++++++++++++++++++++--- include/nand.h | 1 + 2 files changed, 33 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/nand/nand_util.c b/drivers/mtd/nand/nand_util.c index 762ac53..82b41a0 100644 --- a/drivers/mtd/nand/nand_util.c +++ b/drivers/mtd/nand/nand_util.c @@ -11,6 +11,9 @@ * nandwrite.c by Steven J. Hill (sjhill@realitydiluted.com) * and Thomas Gleixner (tglx@linutronix.de) * + * Copyright (C) 2008 Nokia Corporation: drop_ffs() function by + * Artem Bityutskiy dedekind1@gmail.com from mtd-utils + * * See file CREDITS for list of people who contributed to this * project. * @@ -436,6 +439,24 @@ static int check_skip_len(nand_info_t *nand, loff_t offset, size_t length) return ret; }
+#ifdef CONFIG_CMD_NAND_TRIMFFS +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; +} +#endif + /** * nand_write_skip_bad: * @@ -499,7 +520,7 @@ 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 +533,7 @@ 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 +579,15 @@ 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); + truncated_write_size = write_size; +#ifdef CONFIG_CMD_NAND_TRIMFFS + if (flags & WITH_DROP_FFS) + truncated_write_size = drop_ffs(nand, p_buffer, + &write_size); +#endif + + 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 b0a31b8..5c8a189 100644 --- a/include/nand.h +++ b/include/nand.h @@ -116,6 +116,7 @@ int nand_read_skip_bad(nand_info_t *nand, loff_t offset, size_t *length, u_char *buffer);
#define WITH_YAFFS_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);