[U-Boot] [PATCH v2] Correct corrupted NAND Flash access on KARO TX25 modules

[U-Boot] [PATCH v2] Correct corrupted NAND Flash access on KARO TX25 modules

[Gachet Daniel]

This patch v2 correct corrupted data while reading NAND flash modules on the KARO TX25 module.

The current version of the mxc_nand driver uses the symmetric mode to access the NAND flash, but the devices populated on the KARO TX25 only support an asymmetric mode (i.MX25: bit 8  within NAND_FLASH_CONFIG1 register cleared). 

To solve the problem in a generic way, the proposition is to define a specific value for that bit, CONFIG_NAND_MXC_NFC_ONE_CYCLE. This value could be defined in the specific board configuration file (./include/configs/...). Short description:

CONFIG_NAND_MXC_NFC_ONE_CYCLE enables to specify how to access NAND flash on the i.MX25 CPU.
If CONFIG_NAND_MXC_NFC_ONE_CYCLE is defined, a one-clock cycle will be used to access the NAND flash (symmetric mode); otherwise a two-clock cycle will be used (asymmetric mode).

Signed-off-by: Daniel Gachet <daniel.gachet@hefr.ch>
Cc: stefano babic <sbabic@denx.de>

diff -upr drivers/mtd/nand/mxc_nand.c drivers/mtd/nand/mxc_nand.c
--- drivers/mtd/nand/mxc_nand.c	2011-12-23 20:25:35.000000000 +0100
+++ drivers/mtd/nand/mxc_nand.c	2012-04-02 22:30:13.000000000 +0200
@@ -1290,7 +1290,9 @@ static void mxc_setup_config1(void)
 	uint16_t tmp;
 
 	tmp = readw(&host->regs->nfc_config1);
+#ifdef CONFIG_NAND_MXC_NFC_ONE_CYCLE
 	tmp |= NFC_ONE_CYCLE;
+#endif
 	tmp |= NFC_4_8N_ECC;
 	writew(tmp, &host->regs->nfc_config1);
 	if (host->pagesize_2k)

[U-Boot] [PATCH v2] Correct corrupted NAND Flash access on KARO TX25 modules

[Marek Vasut]

Dear Gachet Daniel,

> This patch v2 correct corrupted data while reading NAND flash modules on
> the KARO TX25 module.
> 
> The current version of the mxc_nand driver uses the symmetric mode to
> access the NAND flash, but the devices populated on the KARO TX25 only
> support an asymmetric mode (i.MX25: bit 8  within NAND_FLASH_CONFIG1
> register cleared).
> 
> To solve the problem in a generic way, the proposition is to define a
> specific value for that bit, CONFIG_NAND_MXC_NFC_ONE_CYCLE. This value
> could be defined in the specific board configuration file
> (./include/configs/...). Short description:
> 
> CONFIG_NAND_MXC_NFC_ONE_CYCLE enables to specify how to access NAND flash
> on the i.MX25 CPU. If CONFIG_NAND_MXC_NFC_ONE_CYCLE is defined, a
> one-clock cycle will be used to access the NAND flash (symmetric mode);
> otherwise a two-clock cycle will be used (asymmetric mode).
> 
> Signed-off-by: Daniel Gachet <daniel.gachet@hefr.ch>
> Cc: stefano babic <sbabic@denx.de>
> 
> diff -upr drivers/mtd/nand/mxc_nand.c drivers/mtd/nand/mxc_nand.c
> --- drivers/mtd/nand/mxc_nand.c	2011-12-23 20:25:35.000000000 +0100
> +++ drivers/mtd/nand/mxc_nand.c	2012-04-02 22:30:13.000000000 +0200
> @@ -1290,7 +1290,9 @@ static void mxc_setup_config1(void)
>  	uint16_t tmp;
> 
>  	tmp = readw(&host->regs->nfc_config1);
> +#ifdef CONFIG_NAND_MXC_NFC_ONE_CYCLE
>  	tmp |= NFC_ONE_CYCLE;
> +#endif
>  	tmp |= NFC_4_8N_ECC;
>  	writew(tmp, &host->regs->nfc_config1);
>  	if (host->pagesize_2k)
> 

Won't this break other MX25 boards? Stefano?

Best regards,
Marek Vasut

[U-Boot] [PATCH v2] Correct corrupted NAND Flash access on KARO TX25 modules

[stefano babic]

Am 02/04/2012 22:55, schrieb Gachet Daniel:
> This patch v2 correct corrupted data while reading NAND flash modules on the KARO TX25 module.
> 

Hi Daniel,

> The current version of the mxc_nand driver uses the symmetric mode to access the NAND flash, but the devices populated on the KARO TX25 only support an asymmetric mode (i.MX25: bit 8  within NAND_FLASH_CONFIG1 register cleared). 
> 
> To solve the problem in a generic way, the proposition is to define a specific value for that bit, CONFIG_NAND_MXC_NFC_ONE_CYCLE. This value could be defined in the specific board configuration file (./include/configs/...). Short description:
> 
> CONFIG_NAND_MXC_NFC_ONE_CYCLE enables to specify how to access NAND flash on the i.MX25 CPU.
> If CONFIG_NAND_MXC_NFC_ONE_CYCLE is defined, a one-clock cycle will be used to access the NAND flash (symmetric mode); otherwise a two-clock cycle will be used (asymmetric mode).
> 
> Signed-off-by: Daniel Gachet <daniel.gachet@hefr.ch>
> Cc: stefano babic <sbabic@denx.de>
> 
> diff -upr drivers/mtd/nand/mxc_nand.c drivers/mtd/nand/mxc_nand.c
> --- drivers/mtd/nand/mxc_nand.c	2011-12-23 20:25:35.000000000 +0100
> +++ drivers/mtd/nand/mxc_nand.c	2012-04-02 22:30:13.000000000 +0200
> @@ -1290,7 +1290,9 @@ static void mxc_setup_config1(void)
>  	uint16_t tmp;
>  
>  	tmp = readw(&host->regs->nfc_config1);
> +#ifdef CONFIG_NAND_MXC_NFC_ONE_CYCLE
>  	tmp |= NFC_ONE_CYCLE;
> +#endif

This is not correct. You invert the logic, making as default your board.
But this breaks other boards because none of them set this switch.

To complete your patch you should:
- use an inverted logic, letting as default the current behavior and
modifying the behavior only for your board.
- add the config switch to your board configuration file, that is tx25.h
- add a description in the README file for your new configuration switch

Best regards,
Stefano Babic

-- 
=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot] [PATCH v2] Correct corrupted NAND Flash access on KARO TX25 modules

[stefano babic]

Am 02/04/2012 23:08, schrieb Marek Vasut:
> Dear Gachet Daniel,
> 
>> This patch v2 correct corrupted data while reading NAND flash modules on
>> the KARO TX25 module.
>>
>> The current version of the mxc_nand driver uses the symmetric mode to
>> access the NAND flash, but the devices populated on the KARO TX25 only
>> support an asymmetric mode (i.MX25: bit 8  within NAND_FLASH_CONFIG1
>> register cleared).
>>
>> To solve the problem in a generic way, the proposition is to define a
>> specific value for that bit, CONFIG_NAND_MXC_NFC_ONE_CYCLE. This value
>> could be defined in the specific board configuration file
>> (./include/configs/...). Short description:
>>
>> CONFIG_NAND_MXC_NFC_ONE_CYCLE enables to specify how to access NAND flash
>> on the i.MX25 CPU. If CONFIG_NAND_MXC_NFC_ONE_CYCLE is defined, a
>> one-clock cycle will be used to access the NAND flash (symmetric mode);
>> otherwise a two-clock cycle will be used (asymmetric mode).
>>
>> Signed-off-by: Daniel Gachet <daniel.gachet@hefr.ch>
>> Cc: stefano babic <sbabic@denx.de>
>>
>> diff -upr drivers/mtd/nand/mxc_nand.c drivers/mtd/nand/mxc_nand.c
>> --- drivers/mtd/nand/mxc_nand.c	2011-12-23 20:25:35.000000000 +0100
>> +++ drivers/mtd/nand/mxc_nand.c	2012-04-02 22:30:13.000000000 +0200
>> @@ -1290,7 +1290,9 @@ static void mxc_setup_config1(void)
>>  	uint16_t tmp;
>>
>>  	tmp = readw(&host->regs->nfc_config1);
>> +#ifdef CONFIG_NAND_MXC_NFC_ONE_CYCLE
>>  	tmp |= NFC_ONE_CYCLE;
>> +#endif
>>  	tmp |= NFC_4_8N_ECC;
>>  	writew(tmp, &host->regs->nfc_config1);
>>  	if (host->pagesize_2k)
>>
> 
> Won't this break other MX25 boards? Stefano?

Yes - please check my answer to your patch.

Best regards,
Stefano Babic

-- 
=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de
=====================================================================

[U-Boot] [PATCH v2] Correct corrupted NAND Flash access on KARO TX25 modules

[Gachet Daniel]

Hi Stefano,

No problem, I will do it with the inverse logic, using a CONFIG_NAND_MXC_NFC_TWO_CYCLES, and adapt the tx25.h file.
But could you tell me in which README file I should add the description for that switch? I have a look at all README, but no one has any description about NAND flash configuration flags (like CONFIG_NAND_MXC, CONFIG_NAND_MXC_V1_1  or CONFIG_MXC_NAND_HWECC).

Cordially,

Daniel

-----Original Message-----
From: stefano babic [mailto:sbabic at denx.de] 
Sent: lundi 2 avril 2012 23:54
To: Gachet Daniel
Cc: U-Boot at lists.denx.de; stefano babic
Subject: Re: [U-Boot] [PATCH v2] Correct corrupted NAND Flash access on KARO TX25 modules

Am 02/04/2012 22:55, schrieb Gachet Daniel:
> This patch v2 correct corrupted data while reading NAND flash modules on the KARO TX25 module.
> 

Hi Daniel,

> The current version of the mxc_nand driver uses the symmetric mode to access the NAND flash, but the devices populated on the KARO TX25 only support an asymmetric mode (i.MX25: bit 8  within NAND_FLASH_CONFIG1 register cleared). 
> 
> To solve the problem in a generic way, the proposition is to define a specific value for that bit, CONFIG_NAND_MXC_NFC_ONE_CYCLE. This value could be defined in the specific board configuration file (./include/configs/...). Short description:
> 
> CONFIG_NAND_MXC_NFC_ONE_CYCLE enables to specify how to access NAND flash on the i.MX25 CPU.
> If CONFIG_NAND_MXC_NFC_ONE_CYCLE is defined, a one-clock cycle will be used to access the NAND flash (symmetric mode); otherwise a two-clock cycle will be used (asymmetric mode).
> 
> Signed-off-by: Daniel Gachet <daniel.gachet@hefr.ch>
> Cc: stefano babic <sbabic@denx.de>
> 
> diff -upr drivers/mtd/nand/mxc_nand.c drivers/mtd/nand/mxc_nand.c
> --- drivers/mtd/nand/mxc_nand.c	2011-12-23 20:25:35.000000000 +0100
> +++ drivers/mtd/nand/mxc_nand.c	2012-04-02 22:30:13.000000000 +0200
> @@ -1290,7 +1290,9 @@ static void mxc_setup_config1(void)
>  	uint16_t tmp;
>  
>  	tmp = readw(&host->regs->nfc_config1);
> +#ifdef CONFIG_NAND_MXC_NFC_ONE_CYCLE
>  	tmp |= NFC_ONE_CYCLE;
> +#endif

This is not correct. You invert the logic, making as default your board.
But this breaks other boards because none of them set this switch.

To complete your patch you should:
- use an inverted logic, letting as default the current behavior and modifying the behavior only for your board.
- add the config switch to your board configuration file, that is tx25.h
- add a description in the README file for your new configuration switch

Best regards,
Stefano Babic

--
=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80  Email: office at denx.de =====================================================================

[U-Boot] [PATCH v2] Correct corrupted NAND Flash access on KARO TX25 modules

[Stefano Babic]

On 03/04/2012 07:26, Gachet Daniel wrote:
> Hi Stefano,

Hi Daniel,

> 
> No problem, I will do it with the inverse logic, using a
> CONFIG_NAND_MXC_NFC_TWO_CYCLES, and adapt the tx25.h file. But could
> you tell me in which README file I should add the description for
> that switch? I have a look at all README, but no one has any
> description about NAND flash configuration flags (like
> CONFIG_NAND_MXC, CONFIG_NAND_MXC_V1_1  or CONFIG_MXC_NAND_HWECC).

You have found missing documentation ;-(. Maybe it was not checked
before, but you're right: there is no documentation for this driver.
Even worse, there is no "NAND Support" at all.

Please feel free to add a section. I think the right place is under "Low
Level (hardware related) configuration options", adding a part for the
MXC Nand driver. And if you want to integrate it with the missing
documentation for the other CONFIG_NAND_MXC options, it will be highly
appreciated.

Thanks,
Stefano Babic

-- 
=====================================================================
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
=====================================================================

[U-Boot] [PATCH v2] Correct corrupted NAND Flash access on KARO TX25 modules

[Scott Wood]

On 04/03/2012 07:28 AM, Stefano Babic wrote:
> On 03/04/2012 07:26, Gachet Daniel wrote:
>> Hi Stefano,
>
> Hi Daniel,
>
>>
>> No problem, I will do it with the inverse logic, using a
>> CONFIG_NAND_MXC_NFC_TWO_CYCLES, and adapt the tx25.h file. But could
>> you tell me in which README file I should add the description for
>> that switch? I have a look at all README, but no one has any
>> description about NAND flash configuration flags (like
>> CONFIG_NAND_MXC, CONFIG_NAND_MXC_V1_1  or CONFIG_MXC_NAND_HWECC).
>
> You have found missing documentation ;-(. Maybe it was not checked
> before, but you're right: there is no documentation for this driver.
> Even worse, there is no "NAND Support" at all.
>
> Please feel free to add a section. I think the right place is under "Low
> Level (hardware related) configuration options", adding a part for the
> MXC Nand driver. And if you want to integrate it with the missing
> documentation for the other CONFIG_NAND_MXC options, it will be highly
> appreciated.

There is doc/README.nand that would be appropriate for this, or it could 
go in an MXC-specific file.

-Scott