From c5d8c0cae4af7d78823d32fcd1c458ee1a1b5489 Mon Sep 17 00:00:00 2001 From: Kishore Kadiyala Date: Wed, 11 May 2011 21:17:27 +0530 Subject: [PATCH] mtd: omap: fix subpage ecc issue with prefetch When reading/writing a subpage (When HW ECC is not available/enabled) for number of bytes not aligned to 4, the mis-aligned bytes are handled first (by cpu copy method) before enabling the Prefetch engine to/from 'p'(start of buffer 'buf'). Then it reads/writes rest of the bytes with the help of Prefetch engine, if available, or again using cpu copy method. Currently, reading/writing of rest of bytes, is not done correctly since its trying to read/write again to/from begining of buffer 'buf', overwriting the mis-aligned bytes. Read & write using prefetch engine got broken in commit '2c01946c'. We never hit a scenario of not getting 'gpmc_prefetch_enable' call success. So, problem did not get caught up. Signed-off-by: Kishore Kadiyala Signed-off-by: Vimal Singh Reported-by: Bryan DE FARIA Cc: stable@kernel.org [2.6.35+] Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse --- drivers/mtd/nand/omap2.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c index 288423f7b7b1..39f46a0cf34e 100644 --- a/drivers/mtd/nand/omap2.c +++ b/drivers/mtd/nand/omap2.c @@ -263,11 +263,10 @@ static void omap_read_buf_pref(struct mtd_info *mtd, u_char *buf, int len) if (ret) { /* PFPW engine is busy, use cpu copy method */ if (info->nand.options & NAND_BUSWIDTH_16) - omap_read_buf16(mtd, buf, len); + omap_read_buf16(mtd, (u_char *)p, len); else - omap_read_buf8(mtd, buf, len); + omap_read_buf8(mtd, (u_char *)p, len); } else { - p = (u32 *) buf; do { r_count = gpmc_read_status(GPMC_PREFETCH_FIFO_CNT); r_count = r_count >> 2; @@ -293,7 +292,7 @@ static void omap_write_buf_pref(struct mtd_info *mtd, struct omap_nand_info, mtd); uint32_t w_count = 0; int i = 0, ret = 0; - u16 *p; + u16 *p = (u16 *)buf; unsigned long tim, limit; /* take care of subpage writes */ @@ -309,11 +308,10 @@ static void omap_write_buf_pref(struct mtd_info *mtd, if (ret) { /* PFPW engine is busy, use cpu copy method */ if (info->nand.options & NAND_BUSWIDTH_16) - omap_write_buf16(mtd, buf, len); + omap_write_buf16(mtd, (u_char *)p, len); else - omap_write_buf8(mtd, buf, len); + omap_write_buf8(mtd, (u_char *)p, len); } else { - p = (u16 *) buf; while (len) { w_count = gpmc_read_status(GPMC_PREFETCH_FIFO_CNT); w_count = w_count >> 1; -- 2.34.1