[U-Boot] [PATCH 1/2] nitrogen6x: Pass the correct CPU revision to the kernel

[Dirk Behme]

Am 16.03.2013 17:13, schrieb Eric Nelson:
> On 03/16/2013 07:58 AM, Fabio Estevam wrote:
>> Hi Eric,
>>
>> On Fri, Mar 15, 2013 at 9:20 PM, Eric Nelson
>> <eric.nelson at boundarydevices.com> wrote:
>>
>>> This is the **board** revision, right?
>>>
>>> At first glance, the kernel seems to be getting the silicon revision
>>> from the same place as get_cpu_rev():
>>>
>>> https://github.com/boundarydevices/linux-imx6/blob/boundary-imx_3.0.35_1.1.1/arch/arm/mach-mx6/cpu.c#L51
>>>
>>>
>>> http://git.denx.de/u-boot.git/?p=u-boot.git;a=blob;f=arch/arm/cpu/armv7/mx6/soc.c;h=a8aad5dd0a6c8548277021ebe8f6e159dbf31b9b;hb=HEAD#l42
>>>
>>>
>>> Is there a reference to the ATAG that I'm not seeing somewhere?
>>
>> Ok, so 3.0.35 treats cpu_rev correctly and do not assume this info to
>> be passed from the bootloader. I was confused with 2.6.35, where I had
>> issues with this on mx53.
>>
>> So, it seems that nitrogen does not need to pass get_board_rev() at
>> all then?
>>
> At the moment, it doesn't.
>
> I would really like to see us (the i.MX6 community) standardize
> the use of some fuses to specifically mean board revision.
>
> We're contemplating some board changes such as switching the
> ethernet PHY and having a convention for the use of a few
> bits in OTP would allow us to implement get_board_rev() once in
> a common place.
>
> Over the lifetime of most boards, it's likely that at least
> one board revision will have software implications and having
> a common way to express/detect this could prevent some churn
> in board-specific files.
>
> Such a convention would need to have broad sign off though.
>
> Let me know your thoughts on the subject.

I think the OMAP/Beagle community introduced serial EEPROMs to 
identify their (add on) boards.

Best regards

Dirk