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 <kishore.kadiyala@ti.com>
Signed-off-by: Vimal Singh <vimal.newwork@gmail.com>
Reported-by: Bryan DE FARIA <bdefaria@adeneo-embedded.com>
Cc: stable@kernel.org [2.6.35+]
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 288423f..39f46a0 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -263,11 +263,10 @@
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 @@
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 @@
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;