Re: [U-Boot] [PATCH] imx: mx6sxsabresd: support emmc

2016-01-24 Thread Stefano Babic 
Hi Peng,

On 23/12/2015 04:10, Peng Fan wrote:
> Hi Otavio,
> On Tue, Dec 22, 2015 at 09:51:37AM -0200, Otavio Salvador wrote:
>> On Tue, Dec 22, 2015 at 7:03 AM, Peng Fan  wrote:
>>> From: Peng Fan 
>>>
>>> For i.MX6SX SABRESD, USDHC4 can be used for SD and EMMC, default
>>> it is used for SD.
>>>
>>> This patch introduces EMMC pinmux settings and a new macro
>>> CONFIG_MX6SXSABRESD_EMMC_REWORK. If the board has been reworked
>>> to support emmc, need to enable this macro.
>>>
>>> Signed-off-by: Peng Fan 
>>> Cc: Stefano Babic 
>>
>> Is it worth supporting this 'reworked' board? if someone reworks a
>> board it is expected to have to rework the BSP of it, as well.
> 
> usdhc4 can be used for SD and emmc. This is the feature of the board,
> so I think we need to support it. But there is no way to dynamically check
> whether using sd or emmc now, adding the macro for using emmc.

I agree with Otavio that this is a very nasty hack, and the hardware
developer should provide a way getting the board revision. Anyway, I
would not certainly block it, as it concerns just this board, but I ask
if it is not better to let decide to an environment variable if eMMC
must be activated. Advantage is to have a single U-Boot binary for both
boards, disadvantage is that it coul be set for the wrong board
revision, too. But if USDHC4 was not used anymore, this drives just to a
not found eMMC. Both ways are hacks, I fully agree, but
CONFIG_MX6SXSABRESD_EMMC_REWORK remains undocumented at all, too.

What do you think ?

Best regards,
Stefano Babic

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Re: [U-Boot] [PATCH] imx: mx6sxsabresd: support emmc

2016-01-24 Thread Peng Fan 
Hi Stefano,

On Sun, Jan 24, 2016 at 12:07:14PM +0100, Stefano Babic wrote:
>Hi Peng,
>
>On 23/12/2015 04:10, Peng Fan wrote:
>> Hi Otavio,
>> On Tue, Dec 22, 2015 at 09:51:37AM -0200, Otavio Salvador wrote:
>>> On Tue, Dec 22, 2015 at 7:03 AM, Peng Fan  wrote:
 From: Peng Fan 

 For i.MX6SX SABRESD, USDHC4 can be used for SD and EMMC, default
 it is used for SD.

 This patch introduces EMMC pinmux settings and a new macro
 CONFIG_MX6SXSABRESD_EMMC_REWORK. If the board has been reworked
 to support emmc, need to enable this macro.

 Signed-off-by: Peng Fan 
 Cc: Stefano Babic 
>>>
>>> Is it worth supporting this 'reworked' board? if someone reworks a
>>> board it is expected to have to rework the BSP of it, as well.
>> 
>> usdhc4 can be used for SD and emmc. This is the feature of the board,
>> so I think we need to support it. But there is no way to dynamically check
>> whether using sd or emmc now, adding the macro for using emmc.
>
>I agree with Otavio that this is a very nasty hack, and the hardware
>developer should provide a way getting the board revision. Anyway, I
>would not certainly block it, as it concerns just this board, but I ask
>if it is not better to let decide to an environment variable if eMMC
>must be activated. Advantage is to have a single U-Boot binary for both
>boards, disadvantage is that it coul be set for the wrong board
>revision, too. But if USDHC4 was not used anymore, this drives just to a
>not found eMMC. Both ways are hacks, I fully agree, but
>CONFIG_MX6SXSABRESD_EMMC_REWORK remains undocumented at all, too.
>
>What do you think ?

There is no fuse bit or else to let uboot do runtime checking. I also
disklike this, but I do not have a better idea. Without runtime checking,
it's hard to use one image support SD/EMMC both. I would like to
add doc for the macro CONFIG_MX6SXSABRESD_EMMC_REWORK in the next version, do 
you agree with
this?

Thanks,
Peng.
>
>Best regards,
>Stefano Babic
>
>-- 
>=
>DENX Software Engineering GmbH,  Managing Director: Wolfgang Denk
>HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
>Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sba...@denx.de
>=
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Re: [U-Boot] [PATCH] imx: mx6sxsabresd: support emmc

2016-01-24 Thread Stefano Babic 
Hi Peng,

On 24/01/2016 14:04, Peng Fan wrote:

>> I agree with Otavio that this is a very nasty hack, and the hardware
>> developer should provide a way getting the board revision. Anyway, I
>> would not certainly block it, as it concerns just this board, but I ask
>> if it is not better to let decide to an environment variable if eMMC
>> must be activated. Advantage is to have a single U-Boot binary for both
>> boards, disadvantage is that it coul be set for the wrong board
>> revision, too. But if USDHC4 was not used anymore, this drives just to a
>> not found eMMC. Both ways are hacks, I fully agree, but
>> CONFIG_MX6SXSABRESD_EMMC_REWORK remains undocumented at all, too.
>>
>> What do you think ?
> 
> There is no fuse bit or else to let uboot do runtime checking. I also
> disklike this, but I do not have a better idea. Without runtime checking,
> it's hard to use one image support SD/EMMC both. I would like to
> add doc for the macro CONFIG_MX6SXSABRESD_EMMC_REWORK in the next version, do 
> you agree with
> this?

I add Fabio as he is the board maintainer for mx6sxsabresd.

If adding the #ifdef remains the preferred solution instead of checkin
an env variable, it should be done that it does not generate dead code
as the current patch. That means that a defconfig file must be added
into configs, where CONFIG_MX6SXSABRESD_EMMC_REWORK is set. Else the
code is never built by running buildman and breakages cannot be detected.

Anyway, there are already two files for the board,
mx6sxsabresd_defconfig and mx6sxsabresd_spl_defconfig, and if you want
to have for this board revision both U-Boot with and without SPL, two
additional files are needed - it does not scale very well.


Best regards,
Stefano Babic

-- 
=
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HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sba...@denx.de
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Re: [U-Boot] [PATCH] imx: mx6sxsabresd: support emmc

2015-12-22 Thread Peng Fan 
Hi Otavio,
On Tue, Dec 22, 2015 at 09:51:37AM -0200, Otavio Salvador wrote:
>On Tue, Dec 22, 2015 at 7:03 AM, Peng Fan  wrote:
>> From: Peng Fan 
>>
>> For i.MX6SX SABRESD, USDHC4 can be used for SD and EMMC, default
>> it is used for SD.
>>
>> This patch introduces EMMC pinmux settings and a new macro
>> CONFIG_MX6SXSABRESD_EMMC_REWORK. If the board has been reworked
>> to support emmc, need to enable this macro.
>>
>> Signed-off-by: Peng Fan 
>> Cc: Stefano Babic 
>
>Is it worth supporting this 'reworked' board? if someone reworks a
>board it is expected to have to rework the BSP of it, as well.

usdhc4 can be used for SD and emmc. This is the feature of the board,
so I think we need to support it. But there is no way to dynamically check
whether using sd or emmc now, adding the macro for using emmc.

Regards,
Peng.

>
>-- 
>Otavio Salvador O.S. Systems
>http://www.ossystems.com.brhttp://code.ossystems.com.br
>Mobile: +55 (53) 9981-7854Mobile: +1 (347) 903-9750
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Re: [U-Boot] [PATCH] imx: mx6sxsabresd: support emmc

2015-12-22 Thread Otavio Salvador 
On Tue, Dec 22, 2015 at 7:03 AM, Peng Fan  wrote:
> From: Peng Fan 
>
> For i.MX6SX SABRESD, USDHC4 can be used for SD and EMMC, default
> it is used for SD.
>
> This patch introduces EMMC pinmux settings and a new macro
> CONFIG_MX6SXSABRESD_EMMC_REWORK. If the board has been reworked
> to support emmc, need to enable this macro.
>
> Signed-off-by: Peng Fan 
> Cc: Stefano Babic 

Is it worth supporting this 'reworked' board? if someone reworks a
board it is expected to have to rework the BSP of it, as well.

-- 
Otavio Salvador O.S. Systems
http://www.ossystems.com.brhttp://code.ossystems.com.br
Mobile: +55 (53) 9981-7854Mobile: +1 (347) 903-9750
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