| Message ID | 1304334638-2198-1-git-send-email-kishore.kadiyala@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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.kadiyala@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.kadiyala@ti.com> > Signed-off-by: Vimal Singh <vimal.newwork@gmail.com> > Reported-by: Bryan DE FARIA <bdefaria@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 > > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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.kadiyala@ti.com> > Signed-off-by: Vimal Singh <vimal.newwork@gmail.com> > Reported-by: Bryan DE FARIA <bdefaria@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: stable@kernel.org [2.6.36+] Right? And then we could send it upstream.
On Fri, 2011-05-06 at 13:00 +0530, Vimal Singh wrote: > On Fri, May 6, 2011 at 12:18 AM, Artem Bityutskiy <dedekind1@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.kadiyala@ti.com> > >> Signed-off-by: Vimal Singh <vimal.newwork@gmail.com> > >> Reported-by: Bryan DE FARIA <bdefaria@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: Looks better, thanks. Waiting for the new patch. > > 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.
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;