[U-Boot] [PATCH v2 0/2] SPI flash update command

[U-Boot] [PATCH v2 0/2] SPI flash update command

[Gerlando Falauto]

Hi,

this patchset allows "sf update" to erase+write a number of bytes which is not a
multiple of the sector size.  Start address must still be sector-aligned though.

The first patch trivially makes it such it will always erase an entire sector
before writing, regardless of the amount of data to write (i.e. the last sector
is erased completely before writing it only partially).

The second patch just makes sure that the original data at the end of the sector
is written back so to apparently remain unchanged.

Changes from v1 [April, 03, 2012 (!)]:
 - Rebased on top of u-boot-spi/master

Gerlando Falauto (2):
  cmd_sf: let "sf update" erase last sector as a whole
  cmd_sf: "sf update" preserve the final part of the last sector

 common/cmd_sf.c |   18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

-- 
1.7.10.1

[U-Boot] [PATCH v2 1/2] cmd_sf: let "sf update" erase last sector as a whole

[Gerlando Falauto]

make "sf update" work with unaligned `len' parameter, by deleting the
whole last sector before writing, so to allow for:

 sf update ${load_addr_r} 0 ${filesize}

Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
Cc: Valentin Longchamp <valentin.longchamp@keymile.com>
Cc: Holger Brunck <holger.brunck@keymile.com>
Acked-by: Simon Glass <sjg@chromium.org>
---
 common/cmd_sf.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/common/cmd_sf.c b/common/cmd_sf.c
index 19b0dc9..ab35a94 100644
--- a/common/cmd_sf.c
+++ b/common/cmd_sf.c
@@ -160,7 +160,8 @@ static const char *spi_flash_update_block(struct spi_flash *flash, u32 offset,
 		*skipped += len;
 		return NULL;
 	}
-	if (spi_flash_erase(flash, offset, len))
+	/* Erase the entire sector */
+	if (spi_flash_erase(flash, offset, flash->sector_size))
 		return "erase";
 	if (spi_flash_write(flash, offset, len, buf))
 		return "write";
-- 
1.7.10.1

[U-Boot] [PATCH v2 2/2] cmd_sf: "sf update" preserve the final part of the last sector

[Gerlando Falauto]

Since "sf update" erases the last block as a whole, but only rewrites
the meaningful initial part of it, the rest would be left erased,
potentially erasing meaningful information.
So, as a safety measure, have it rewrite the original content.

Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
Cc: Valentin Longchamp <valentin.longchamp@keymile.com>
Cc: Holger Brunck <holger.brunck@keymile.com>
Acked-by: Simon Glass <sjg@chromium.org>
---
 common/cmd_sf.c |   15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/common/cmd_sf.c b/common/cmd_sf.c
index ab35a94..fb87d24 100644
--- a/common/cmd_sf.c
+++ b/common/cmd_sf.c
@@ -152,8 +152,10 @@ static const char *spi_flash_update_block(struct spi_flash *flash, u32 offset,
 {
 	debug("offset=%#x, sector_size=%#x, len=%#zx\n",
 		offset, flash->sector_size, len);
-	if (spi_flash_read(flash, offset, len, cmp_buf))
+	/* Read the entire sector so to allow for rewriting */
+	if (spi_flash_read(flash, offset, flash->sector_size, cmp_buf))
 		return "read";
+	/* Compare only what is meningful (len) */
 	if (memcmp(cmp_buf, buf, len) == 0) {
 		debug("Skip region %x size %zx: no change\n",
 			offset, len);
@@ -163,6 +165,17 @@ static const char *spi_flash_update_block(struct spi_flash *flash, u32 offset,
 	/* Erase the entire sector */
 	if (spi_flash_erase(flash, offset, flash->sector_size))
 		return "erase";
+	/* If it's a partial sector, preserve the existing part */
+	if (len != flash->sector_size) {
+		/* Overwrite the first part of the sector with input data */
+		memcpy(cmp_buf, buf, len);
+		/* Rewrite the whole sector with original data at the end */
+		if (spi_flash_write(flash, offset, flash->sector_size,
+					cmp_buf))
+			return "write";
+		return NULL;
+	}
+	/* Rewrite the whole block from the source */
 	if (spi_flash_write(flash, offset, len, buf))
 		return "write";
 	return NULL;
-- 
1.7.10.1

[U-Boot] [PATCH v2 2/2] cmd_sf: "sf update" preserve the final part of the last sector

[Jagan Teki]

Hi,

Thanks for the v2.

On Fri, Jun 28, 2013 at 1:13 PM, Gerlando Falauto
<gerlando.falauto@keymile.com> wrote:
> Since "sf update" erases the last block as a whole, but only rewrites
> the meaningful initial part of it, the rest would be left erased,
> potentially erasing meaningful information.
> So, as a safety measure, have it rewrite the original content.
>
> Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
> Cc: Valentin Longchamp <valentin.longchamp@keymile.com>
> Cc: Holger Brunck <holger.brunck@keymile.com>
> Acked-by: Simon Glass <sjg@chromium.org>
> ---
>  common/cmd_sf.c |   15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/common/cmd_sf.c b/common/cmd_sf.c
> index ab35a94..fb87d24 100644
> --- a/common/cmd_sf.c
> +++ b/common/cmd_sf.c
> @@ -152,8 +152,10 @@ static const char *spi_flash_update_block(struct spi_flash *flash, u32 offset,
>  {
>         debug("offset=%#x, sector_size=%#x, len=%#zx\n",
>                 offset, flash->sector_size, len);
> -       if (spi_flash_read(flash, offset, len, cmp_buf))
> +       /* Read the entire sector so to allow for rewriting */
> +       if (spi_flash_read(flash, offset, flash->sector_size, cmp_buf))
>                 return "read";
> +       /* Compare only what is meningful (len) */
>         if (memcmp(cmp_buf, buf, len) == 0) {
>                 debug("Skip region %x size %zx: no change\n",
>                         offset, len);
> @@ -163,6 +165,17 @@ static const char *spi_flash_update_block(struct spi_flash *flash, u32 offset,
>         /* Erase the entire sector */
>         if (spi_flash_erase(flash, offset, flash->sector_size))
>                 return "erase";
> +       /* If it's a partial sector, preserve the existing part */
> +       if (len != flash->sector_size) {
> +               /* Overwrite the first part of the sector with input data */
> +               memcpy(cmp_buf, buf, len);

Can comment about memcpy() here, as Simon is also asked in v1
http://patchwork.ozlabs.org/patch/150468/

--
Thanks,
Jagan.

> +               /* Rewrite the whole sector with original data at the end */
> +               if (spi_flash_write(flash, offset, flash->sector_size,
> +                                       cmp_buf))
> +                       return "write";
> +               return NULL;
> +       }
> +       /* Rewrite the whole block from the source */
>         if (spi_flash_write(flash, offset, len, buf))
>                 return "write";
>         return NULL;
> --
> 1.7.10.1
>

[U-Boot] [PATCH v2 2/2] cmd_sf: "sf update" preserve the final part of the last sector

[Gerlando Falauto]

Hi,

On 07/03/2013 05:04 PM, Jagan Teki wrote:
> Hi,
>
> Thanks for the v2.
>
> On Fri, Jun 28, 2013 at 1:13 PM, Gerlando Falauto
> <gerlando.falauto@keymile.com> wrote:
>> Since "sf update" erases the last block as a whole, but only rewrites
>> the meaningful initial part of it, the rest would be left erased,
>> potentially erasing meaningful information.
>> So, as a safety measure, have it rewrite the original content.
>>
>> Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>
>> Cc: Valentin Longchamp <valentin.longchamp@keymile.com>
>> Cc: Holger Brunck <holger.brunck@keymile.com>
>> Acked-by: Simon Glass <sjg@chromium.org>
>> ---
>>   common/cmd_sf.c |   15 ++++++++++++++-
>>   1 file changed, 14 insertions(+), 1 deletion(-)
>>
>> diff --git a/common/cmd_sf.c b/common/cmd_sf.c
>> index ab35a94..fb87d24 100644
>> --- a/common/cmd_sf.c
>> +++ b/common/cmd_sf.c
>> @@ -152,8 +152,10 @@ static const char *spi_flash_update_block(struct spi_flash *flash, u32 offset,
>>   {
>>          debug("offset=%#x, sector_size=%#x, len=%#zx\n",
>>                  offset, flash->sector_size, len);
>> -       if (spi_flash_read(flash, offset, len, cmp_buf))
>> +       /* Read the entire sector so to allow for rewriting */
>> +       if (spi_flash_read(flash, offset, flash->sector_size, cmp_buf))
>>                  return "read";
>> +       /* Compare only what is meningful (len) */
>>          if (memcmp(cmp_buf, buf, len) == 0) {
>>                  debug("Skip region %x size %zx: no change\n",
>>                          offset, len);
>> @@ -163,6 +165,17 @@ static const char *spi_flash_update_block(struct spi_flash *flash, u32 offset,
>>          /* Erase the entire sector */
>>          if (spi_flash_erase(flash, offset, flash->sector_size))
>>                  return "erase";
>> +       /* If it's a partial sector, preserve the existing part */
>> +       if (len != flash->sector_size) {
>> +               /* Overwrite the first part of the sector with input data */
>> +               memcpy(cmp_buf, buf, len);
>
> Can comment about memcpy() here, as Simon is also asked in v1
> http://patchwork.ozlabs.org/patch/150468/

Whoops, sorry!
I most probably did not see the comment (stopped reading at the Acked-By 
line) the first time around and *DEFINITELY* did not see it before 
posting v2.

I now understand your point, Simon.
This would imply two spi_flash_write() operations as opposed to just 
one, yet allowing for cleaner code.
I guess I was originally trying to both preserve the original behavior 
(always write whole sectors) and save on the number of write operations.
But that does not make much sense as we're speaking of an SPI NOR flash 
here, the only penalty from an extra write operation only comes from the 
extra SPI command. Not really much.

I'll post a v3 soon.

My apologies again.

Thanks,
Gerlando

>
> --
> Thanks,
> Jagan.
>
>> +               /* Rewrite the whole sector with original data at the end */
>> +               if (spi_flash_write(flash, offset, flash->sector_size,
>> +                                       cmp_buf))
>> +                       return "write";
>> +               return NULL;
>> +       }
>> +       /* Rewrite the whole block from the source */
>>          if (spi_flash_write(flash, offset, len, buf))
>>                  return "write";
>>          return NULL;
>> --
>> 1.7.10.1
>>