[U-Boot] [PATCH] mx6sabresd: Move the DCD settings to spl code

[Stefano Babic]

Hi Nikolay,

On 14/11/2014 13:22, Nikolay Dimitrov wrote:
> Hi Fabio,
> 
> On 11/14/2014 01:57 PM, Fabio Estevam wrote:
>> Hi Nikolay,
>>
>> On Fri, Nov 14, 2014 at 9:48 AM, Nikolay Dimitrov <picmaster at mail.bg>
>> wrote:
>>> Hi Fabio,
>>>
>>> On 11/13/2014 11:58 PM, Fabio Estevam wrote:
>>>>
>>>> From: Fabio Estevam <fabio.estevam at freescale.com>
>>>>
>>>> mx6sabresd_spl.cfg configures CCM registers, GPR registers and
>>>> CCM_CCOSR.
>>>>
>>>> Move the configuration to the spl code.
>>>
>>>
>>> I forgot to asker earlier, but what are the benefits of going from
>>> DCD to
>>> SPL code to provide HW initialization?
>>
>> We already went through the hard part of removing the DDR settings
>> from DCD in the SPL case. Now all is left is a few register writes
>> that could be better placed into SPL code.
>>
>> Some advantages:
>>
>> - Shorter and cleaner code - see the stat diff of this series. This
>> will avoid lots of duplication of the same spl DCD settings for
>> several boards.
>> - Do all the register settings in C rather than in a static DCD table.
>> Easier to maintain and provide future changes.
>> - We really don't need to do such simple register settings from DCD ;-)
> 

There is another advantage: it is possible to provide a single binary
for boards that can mount different processor,sucs as MX6Q or MX6DL. Due
to different layout, the registers are not the same, and the DCD is, of
course, fix.

With SPL we are able to detect at runtime the SOC and set the registers
consequently. With DCD, we need to rebuild U-Boot and deliver different
binaries - that is also confusing for the end customer.

Best regards,
Stefano Babic

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