Re: [PATCH] omap : nand : fix subpage ecc issue with prefetch
On Fri, May 6, 2011 at 12:18 AM, Artem Bityutskiy dedeki...@gmail.com wrote: On Mon, 2011-05-02 at 16:40 +0530, Kishore Kadiyala wrote: For prefetch engine, read and write got broken in commit '2c01946c'. We never hit a scenario of not getting 'gpmc_prefetch_enable' call success. When reading/writing a subpage with a non divisible by 4 ecc number of bytes, the mis-aligned bytes gets handled first before enabling the Prefetch engine, then it reads/writes rest of the bytes. Signed-off-by: Kishore Kadiyala kishore.kadiy...@ti.com Signed-off-by: Vimal Singh vimal.neww...@gmail.com Reported-by: Bryan DE FARIA bdefa...@adeneo-embedded.com This needs a better commit message with more explanation and analysis of the problem and how it was fixed.This commit message is not very understandable. And then it needs also: How about a commit log like this: When reading/writing a subpage (When HW ECC is not available/enable) for number of bytes not aligned to 4, the mis-aligned bytes gets handled first (by cpu copy mathod) before enabling the Prefetch engin 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 by cpu copy mathod. Currnetly, reading/writing of rest of bytes, is not done correctly. Its trying to read/write again to/from begining of buffer 'buf', overwriting the mis-aligned bytes. For prefetch engine read and write it got broken in commit '2c01946c'. And we never hit the scenario of not getting 'gpmc_prefetch_enable' call sucess. So, problem did not get caught up. This patch fixes the issue. Cc: sta...@kernel.org [2.6.36+] Right? And then we could send it upstream. Yes, sure. I think kishore can take care of adding this in 'cc' while posting next time. -- Regards, Vimal Singh -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] omap : nand : fix subpage ecc issue with prefetch
Hi Artem,
Can you please give a look on this patch?
This patch fixes is required for anyone who wants to use this driver
without using HW ECC.
-- Vimal
On Mon, May 2, 2011 at 4:40 PM, Kishore Kadiyala
kishore.kadiy...@ti.com wrote:
For prefetch engine, read and write got broken in commit '2c01946c'.
We never hit a scenario of not getting 'gpmc_prefetch_enable'
call success.
When reading/writing a subpage with a non divisible by 4 ecc number
of bytes, the mis-aligned bytes gets handled first before enabling
the Prefetch engine, then it reads/writes rest of the bytes.
Signed-off-by: Kishore Kadiyala kishore.kadiy...@ti.com
Signed-off-by: Vimal Singh vimal.neww...@gmail.com
Reported-by: Bryan DE FARIA bdefa...@adeneo-embedded.com
---
drivers/mtd/nand/omap2.c | 12 +---
1 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index da9a351..2c8040f 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;
--
1.7.4.1
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Re: [PATCH] omap : nand : fix subpage ecc issue with prefetch
On Mon, 2011-05-02 at 16:40 +0530, Kishore Kadiyala wrote: For prefetch engine, read and write got broken in commit '2c01946c'. We never hit a scenario of not getting 'gpmc_prefetch_enable' call success. When reading/writing a subpage with a non divisible by 4 ecc number of bytes, the mis-aligned bytes gets handled first before enabling the Prefetch engine, then it reads/writes rest of the bytes. Signed-off-by: Kishore Kadiyala kishore.kadiy...@ti.com Signed-off-by: Vimal Singh vimal.neww...@gmail.com Reported-by: Bryan DE FARIA bdefa...@adeneo-embedded.com This needs a better commit message with more explanation and analysis of the problem and how it was fixed.This commit message is not very understandable. And then it needs also: Cc: sta...@kernel.org [2.6.36+] Right? And then we could send it upstream. -- Best Regards, Artem Bityutskiy (Артём Битюцкий) -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH] omap : nand : fix subpage ecc issue with prefetch
For prefetch engine, read and write got broken in commit '2c01946c'.
We never hit a scenario of not getting 'gpmc_prefetch_enable'
call success.
When reading/writing a subpage with a non divisible by 4 ecc number
of bytes, the mis-aligned bytes gets handled first before enabling
the Prefetch engine, then it reads/writes rest of the bytes.
Signed-off-by: Kishore Kadiyala kishore.kadiy...@ti.com
Signed-off-by: Vimal Singh vimal.neww...@gmail.com
Reported-by: Bryan DE FARIA bdefa...@adeneo-embedded.com
---
drivers/mtd/nand/omap2.c | 12 +---
1 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index da9a351..2c8040f 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;
--
1.7.4.1
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