[PATCH v2] 16 bit NAND fix, request for testers

[PATCH v2] 16 bit NAND fix, request for testers

[Christopher Harvey]

just a small patch to access GPMC NAND registers with 16 bits when the
NAND is in 16 bit mode. I tested this on a 2.6.37 kernel, and noticed
it was still unpatched in the latest kernel. I don't have the hardware
setup or defconfigs to test this patch out, and even if I did I don't
have the logic analyzer setup to completely reproduce it on other
hardware with the latest kernel. It would be nice to get a tested-by
on this patch.

(CC'd mtd list this time)

Thanks.


Christopher Harvey (1):
  mtd: omap: nand: Remove 0xFF's that prefixed 16bit NAND commands

 drivers/mtd/nand/omap2.c |   14 +++++++++-----
 1 files changed, 9 insertions(+), 5 deletions(-)

-- 
1.7.8.6

[PATCH v2] mtd: omap: nand: Remove 0xFF's that prefixed 16bit NAND commands

[Christopher Harvey]

In 16bit NAND mode the GPMC would send the command 0xNN as 0xFFNN
instead of 0x00NN on the bus. The 0xFFs were actually uninitialized
bits that were left unset in the GPMC command output register. The
reason they weren't initialized in 16bit mode is that if the same code
that writes to this register was used in 8bit mode then 2 commands
would be output in 8bit mode. One for the low byte, and an extra 0x0
command for the high byte. This commit uses writew if we're using
16bit NAND.

Most chips seem fine with the extra 0xFFs, but the ONFI spec says
otherwise.

Signed-off-by: Christopher Harvey <charvey@matrox.com>
---
 drivers/mtd/nand/omap2.c |   14 +++++++++-----
 1 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 5b31386..ae6738f 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -225,16 +225,20 @@ static void omap_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 {
 	struct omap_nand_info *info = container_of(mtd,
 					struct omap_nand_info, mtd);
+	void __iomem *reg;
 
 	if (cmd != NAND_CMD_NONE) {
 		if (ctrl & NAND_CLE)
-			writeb(cmd, info->reg.gpmc_nand_command);
-
+			reg = info->reg.gpmc_nand_command;
 		else if (ctrl & NAND_ALE)
-			writeb(cmd, info->reg.gpmc_nand_address);
-
+			reg = info->reg.gpmc_nand_address;
 		else /* NAND_NCE */
-			writeb(cmd, info->reg.gpmc_nand_data);
+			reg = info->reg.gpmc_nand_data;
+
+		if (info->nand.options & NAND_BUSWIDTH_16)
+			writew(cmd, reg);
+		else
+			writeb(cmd, reg);
 	}
 }
 
-- 
1.7.8.6

Re: [PATCH v2] mtd: omap: nand: Remove 0xFF's that prefixed 16bit NAND commands

[Ivan Djelic]

On Fri, Oct 26, 2012 at 08:36:43PM +0100, Christopher Harvey wrote:
> In 16bit NAND mode the GPMC would send the command 0xNN as 0xFFNN
> instead of 0x00NN on the bus. The 0xFFs were actually uninitialized
> bits that were left unset in the GPMC command output register. The
> reason they weren't initialized in 16bit mode is that if the same code
> that writes to this register was used in 8bit mode then 2 commands
> would be output in 8bit mode. One for the low byte, and an extra 0x0
> command for the high byte. This commit uses writew if we're using
> 16bit NAND.
> 
> Most chips seem fine with the extra 0xFFs, but the ONFI spec says
> otherwise.

Hi Christopher,

Nitpick: I think you should replace 'command' with 'address' in your commit message.
The ONFI spec says Host should send _address_ byte NN as 0x00NN. It is OK to send
command NN as 0xFFNN, as explicitly mentioned in ONFI 3.1 spec (section 2.16):

  2.16.          Bus Width Requirements
All NAND Targets per device shall use the same data bus width. All targets shall either have an
8-bit bus width or a 16-bit bus width. Note that devices that support the NV-DDR or NV-DDR2
data interface shall have an 8-bit bus width.
When the host supports a 16-bit bus width, only data is transferred at the 16-bit width. All
address and command line transfers shall use only the lower 8-bits of the data bus. During
command transfers, the host may place any value on the upper 8-bits of the data bus. During
address transfers, the host shall set the upper 8-bits of the data bus to 00h.

Your patch deals with both command and address bytes, which does not hurt.
BR,
--
Ivan

> 
> Signed-off-by: Christopher Harvey <charvey@matrox.com>
> ---
>  drivers/mtd/nand/omap2.c |   14 +++++++++-----
>  1 files changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
> index 5b31386..ae6738f 100644
> --- a/drivers/mtd/nand/omap2.c
> +++ b/drivers/mtd/nand/omap2.c
> @@ -225,16 +225,20 @@ static void omap_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
>  {
>  	struct omap_nand_info *info = container_of(mtd,
>  					struct omap_nand_info, mtd);
> +	void __iomem *reg;
>  
>  	if (cmd != NAND_CMD_NONE) {
>  		if (ctrl & NAND_CLE)
> -			writeb(cmd, info->reg.gpmc_nand_command);
> -
> +			reg = info->reg.gpmc_nand_command;
>  		else if (ctrl & NAND_ALE)
> -			writeb(cmd, info->reg.gpmc_nand_address);
> -
> +			reg = info->reg.gpmc_nand_address;
>  		else /* NAND_NCE */
> -			writeb(cmd, info->reg.gpmc_nand_data);
> +			reg = info->reg.gpmc_nand_data;
> +
> +		if (info->nand.options & NAND_BUSWIDTH_16)
> +			writew(cmd, reg);
> +		else
> +			writeb(cmd, reg);
>  	}
>  }
>  
> -- 
> 1.7.8.6
> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH v2] mtd: omap: nand: Remove 0xFF's that prefixed 16bit NAND commands

[Christopher Harvey]

On Mon, Oct 29, 2012 at 02:49:03PM +0100, Ivan Djelic wrote:
> On Fri, Oct 26, 2012 at 08:36:43PM +0100, Christopher Harvey wrote:
> > In 16bit NAND mode the GPMC would send the command 0xNN as 0xFFNN
> > instead of 0x00NN on the bus. The 0xFFs were actually uninitialized
> > bits that were left unset in the GPMC command output register. The
> > reason they weren't initialized in 16bit mode is that if the same code
> > that writes to this register was used in 8bit mode then 2 commands
> > would be output in 8bit mode. One for the low byte, and an extra 0x0
> > command for the high byte. This commit uses writew if we're using
> > 16bit NAND.
> > 
> > Most chips seem fine with the extra 0xFFs, but the ONFI spec says
> > otherwise.
> 
> Hi Christopher,
> 
> Nitpick: I think you should replace 'command' with 'address' in your commit message.
> The ONFI spec says Host should send _address_ byte NN as 0x00NN. It is OK to send
> command NN as 0xFFNN, as explicitly mentioned in ONFI 3.1 spec (section 2.16):
> 
>   2.16.          Bus Width Requirements
> All NAND Targets per device shall use the same data bus width. All targets shall either have an
> 8-bit bus width or a 16-bit bus width. Note that devices that support the NV-DDR or NV-DDR2
> data interface shall have an 8-bit bus width.
> When the host supports a 16-bit bus width, only data is transferred at the 16-bit width. All
> address and command line transfers shall use only the lower 8-bits of the data bus. During
> command transfers, the host may place any value on the upper 8-bits of the data bus. During
> address transfers, the host shall set the upper 8-bits of the data bus to 00h.
> 
> Your patch deals with both command and address bytes, which does not hurt.
> BR,
> --
> Ivan

Ok, makes sense. Thanks for pointing that out. I'll update the wording.

> > 
> > Signed-off-by: Christopher Harvey <charvey@matrox.com>
> > ---
> >  drivers/mtd/nand/omap2.c |   14 +++++++++-----
> >  1 files changed, 9 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
> > index 5b31386..ae6738f 100644
> > --- a/drivers/mtd/nand/omap2.c
> > +++ b/drivers/mtd/nand/omap2.c
> > @@ -225,16 +225,20 @@ static void omap_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
> >  {
> >  	struct omap_nand_info *info = container_of(mtd,
> >  					struct omap_nand_info, mtd);
> > +	void __iomem *reg;
> >  
> >  	if (cmd != NAND_CMD_NONE) {
> >  		if (ctrl & NAND_CLE)
> > -			writeb(cmd, info->reg.gpmc_nand_command);
> > -
> > +			reg = info->reg.gpmc_nand_command;
> >  		else if (ctrl & NAND_ALE)
> > -			writeb(cmd, info->reg.gpmc_nand_address);
> > -
> > +			reg = info->reg.gpmc_nand_address;
> >  		else /* NAND_NCE */
> > -			writeb(cmd, info->reg.gpmc_nand_data);
> > +			reg = info->reg.gpmc_nand_data;
> > +
> > +		if (info->nand.options & NAND_BUSWIDTH_16)
> > +			writew(cmd, reg);
> > +		else
> > +			writeb(cmd, reg);
> >  	}
> >  }
> >  
> > -- 
> > 1.7.8.6
> > 

[PATCH v3] mtd: omap: nand: Remove 0xFF's that prefixed 16bit NAND addresses

[Christopher Harvey]

In 16bit NAND mode the GPMC would send the address 0xNN as 0xFFNN
instead of 0x00NN on the bus. The 0xFFs were actually uninitialized
bits that were left unset in the GPMC command output register. The
reason they weren't initialized in 16bit mode is that if the same code
that writes to this register was used in 8bit mode then 2 commands
would be output in 8bit mode. One for the low byte, and an extra 0x0
command for the high byte. This commit uses writew if we're using
16bit NAND. This commit also changes the high byte in the command
output register, but they are ignored by NAND chips anyway.

Most chips seem fine with the extra 0xFFs, but the ONFI spec says
otherwise.

Signed-off-by: Christopher Harvey <charvey@matrox.com>
---
 drivers/mtd/nand/omap2.c |   14 +++++++++-----
 1 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 5b31386..ae6738f 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -225,16 +225,20 @@ static void omap_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 {
 	struct omap_nand_info *info = container_of(mtd,
 					struct omap_nand_info, mtd);
+	void __iomem *reg;
 
 	if (cmd != NAND_CMD_NONE) {
 		if (ctrl & NAND_CLE)
-			writeb(cmd, info->reg.gpmc_nand_command);
-
+			reg = info->reg.gpmc_nand_command;
 		else if (ctrl & NAND_ALE)
-			writeb(cmd, info->reg.gpmc_nand_address);
-
+			reg = info->reg.gpmc_nand_address;
 		else /* NAND_NCE */
-			writeb(cmd, info->reg.gpmc_nand_data);
+			reg = info->reg.gpmc_nand_data;
+
+		if (info->nand.options & NAND_BUSWIDTH_16)
+			writew(cmd, reg);
+		else
+			writeb(cmd, reg);
 	}
 }
 
-- 
1.7.8.6

Re: [PATCH v3] mtd: omap: nand: Remove 0xFF's that prefixed 16bit NAND addresses

[Artem Bityutskiy]

[-- Attachment #1: Type: text/plain, Size: 911 bytes --]

On Mon, 2012-10-29 at 15:51 -0400, Christopher Harvey wrote:
> In 16bit NAND mode the GPMC would send the address 0xNN as 0xFFNN
> instead of 0x00NN on the bus. The 0xFFs were actually uninitialized
> bits that were left unset in the GPMC command output register. The
> reason they weren't initialized in 16bit mode is that if the same code
> that writes to this register was used in 8bit mode then 2 commands
> would be output in 8bit mode. One for the low byte, and an extra 0x0
> command for the high byte. This commit uses writew if we're using
> 16bit NAND. This commit also changes the high byte in the command
> output register, but they are ignored by NAND chips anyway.
> 
> Most chips seem fine with the extra 0xFFs, but the ONFI spec says
> otherwise.
> 
> Signed-off-by: Christopher Harvey <charvey@matrox.com>

Pushed to l2-mtd.git, thanks!

-- 
Best Regards,
Artem Bityutskiy

[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 836 bytes --]

Re: [PATCH v3] mtd: omap: nand: Remove 0xFF's that prefixed 16bit NAND addresses

[Christopher Harvey]

On Thu, Nov 15, 2012 at 01:02:09PM +0200, Artem Bityutskiy wrote:
> On Mon, 2012-10-29 at 15:51 -0400, Christopher Harvey wrote:
> > In 16bit NAND mode the GPMC would send the address 0xNN as 0xFFNN
> > instead of 0x00NN on the bus. The 0xFFs were actually uninitialized
> > bits that were left unset in the GPMC command output register. The
> > reason they weren't initialized in 16bit mode is that if the same code
> > that writes to this register was used in 8bit mode then 2 commands
> > would be output in 8bit mode. One for the low byte, and an extra 0x0
> > command for the high byte. This commit uses writew if we're using
> > 16bit NAND. This commit also changes the high byte in the command
> > output register, but they are ignored by NAND chips anyway.
> > 
> > Most chips seem fine with the extra 0xFFs, but the ONFI spec says
> > otherwise.
> > 
> > Signed-off-by: Christopher Harvey <charvey@matrox.com>
> 
> Pushed to l2-mtd.git, thanks!

!!! Did anybody get around to testing this? I thought this patch had
    been abandoned. Will testing get done on an omap chip now that it
    is in a tree?

I should have prefixed it with RFC.

-C

-- 

CONFIDENTIAL & WITHOUT PREJUDICE

This e-mail and any files transmitted with it, is confidential, may be
protected under NDA and/or privileged and shall be treated as
such. The e-mail and its attachments are intended only for use of the
individual(s) or entity(ies) indicated above. Any other person is
hereby advised that it strictly forbidden to disclose, distribute or
reproduce this message.  If you have received this e-mail in error,
please advise me by return e-mail or by telephone at 514-822-6000,
immediately and destroy the message and its contents immediately.
Thank You.

CONFIDENTIEL - SANS PRÉJUDICE

Ce courriel et tout document qui y est joint, est confidentiel, peut
être privilégié et protégé par entente de confidentialité et est à
l'usage exclusif du destinataire. Toute autre personne est par les
présentes avisée qu'il lui est strictement interdit de le diffuser, le
distribuer ou le reproduire. Si vous recevez ce courriel par erreur,
veuillez m'en aviser immédiatement, par retour de courriel ou par
téléphone au (514) 822-6000 et détruire ce message et toute copie de
celui-ci immédiatement.  Merci.

--
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

Re: [PATCH v3] mtd: omap: nand: Remove 0xFF's that prefixed 16bit NAND addresses

[Artem Bityutskiy]

[-- Attachment #1: Type: text/plain, Size: 1414 bytes --]

On Thu, 2012-11-15 at 09:48 -0500, Christopher Harvey wrote:
> On Thu, Nov 15, 2012 at 01:02:09PM +0200, Artem Bityutskiy wrote:
> > On Mon, 2012-10-29 at 15:51 -0400, Christopher Harvey wrote:
> > > In 16bit NAND mode the GPMC would send the address 0xNN as 0xFFNN
> > > instead of 0x00NN on the bus. The 0xFFs were actually uninitialized
> > > bits that were left unset in the GPMC command output register. The
> > > reason they weren't initialized in 16bit mode is that if the same code
> > > that writes to this register was used in 8bit mode then 2 commands
> > > would be output in 8bit mode. One for the low byte, and an extra 0x0
> > > command for the high byte. This commit uses writew if we're using
> > > 16bit NAND. This commit also changes the high byte in the command
> > > output register, but they are ignored by NAND chips anyway.
> > > 
> > > Most chips seem fine with the extra 0xFFs, but the ONFI spec says
> > > otherwise.
> > > 
> > > Signed-off-by: Christopher Harvey <charvey@matrox.com>
> > 
> > Pushed to l2-mtd.git, thanks!
> 
> !!! Did anybody get around to testing this? I thought this patch had
>     been abandoned. Will testing get done on an omap chip now that it
>     is in a tree?
> 
> I should have prefixed it with RFC.

I assume _you_ tested it, and Ivan was happy. But if it is untested, I
am dropping it.

-- 
Best Regards,
Artem Bityutskiy

[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 836 bytes --]

Re: [PATCH v3] mtd: omap: nand: Remove 0xFF's that prefixed 16bit NAND addresses

[Christopher Harvey]

On Thu, Nov 15, 2012 at 05:18:44PM +0200, Artem Bityutskiy wrote:
> On Thu, 2012-11-15 at 09:48 -0500, Christopher Harvey wrote:
> > On Thu, Nov 15, 2012 at 01:02:09PM +0200, Artem Bityutskiy wrote:
> > > On Mon, 2012-10-29 at 15:51 -0400, Christopher Harvey wrote:
> > > > In 16bit NAND mode the GPMC would send the address 0xNN as 0xFFNN
> > > > instead of 0x00NN on the bus. The 0xFFs were actually uninitialized
> > > > bits that were left unset in the GPMC command output register. The
> > > > reason they weren't initialized in 16bit mode is that if the same code
> > > > that writes to this register was used in 8bit mode then 2 commands
> > > > would be output in 8bit mode. One for the low byte, and an extra 0x0
> > > > command for the high byte. This commit uses writew if we're using
> > > > 16bit NAND. This commit also changes the high byte in the command
> > > > output register, but they are ignored by NAND chips anyway.
> > > > 
> > > > Most chips seem fine with the extra 0xFFs, but the ONFI spec says
> > > > otherwise.
> > > > 
> > > > Signed-off-by: Christopher Harvey <charvey@matrox.com>
> > > 
> > > Pushed to l2-mtd.git, thanks!
> > 
> > !!! Did anybody get around to testing this? I thought this patch had
> >     been abandoned. Will testing get done on an omap chip now that it
> >     is in a tree?
> > 
> > I should have prefixed it with RFC.
> 
> I assume _you_ tested it, and Ivan was happy. But if it is untested, I
> am dropping it.
> 

I'm running a slight variation of it on another version of the
kernel. I'm glad you're dropping it though...I have a reputation to
maintain as well as a kernel. ;)

-C

Re: [PATCH v3] mtd: omap: nand: Remove 0xFF's that prefixed 16bit NAND addresses

[Ivan Djelic]

On Thu, Nov 15, 2012 at 03:18:44PM +0000, Artem Bityutskiy wrote:
> On Thu, 2012-11-15 at 09:48 -0500, Christopher Harvey wrote:
> > On Thu, Nov 15, 2012 at 01:02:09PM +0200, Artem Bityutskiy wrote:
> > > On Mon, 2012-10-29 at 15:51 -0400, Christopher Harvey wrote:
> > > > In 16bit NAND mode the GPMC would send the address 0xNN as 0xFFNN
> > > > instead of 0x00NN on the bus. The 0xFFs were actually uninitialized
> > > > bits that were left unset in the GPMC command output register. The
> > > > reason they weren't initialized in 16bit mode is that if the same code
> > > > that writes to this register was used in 8bit mode then 2 commands
> > > > would be output in 8bit mode. One for the low byte, and an extra 0x0
> > > > command for the high byte. This commit uses writew if we're using
> > > > 16bit NAND. This commit also changes the high byte in the command
> > > > output register, but they are ignored by NAND chips anyway.
> > > > 
> > > > Most chips seem fine with the extra 0xFFs, but the ONFI spec says
> > > > otherwise.
> > > > 
> > > > Signed-off-by: Christopher Harvey <charvey@matrox.com>
> > > 
> > > Pushed to l2-mtd.git, thanks!
> > 
> > !!! Did anybody get around to testing this? I thought this patch had
> >     been abandoned. Will testing get done on an omap chip now that it
> >     is in a tree?
> > 
> > I should have prefixed it with RFC.
> 
> I assume _you_ tested it, and Ivan was happy. But if it is untested, I
> am dropping it.

Unfortunately I can't test it at the moment,
BR,
--
Ivan