[U-Boot] [PATCH] ARMV7: OMAP4: Calculate SDRAM size

Nishanth Menon menon.nishanth at gmail.com
Sun Sep 26 17:28:50 CEST 2010


On 09/26/2010 09:57 AM, Steve Sakoman wrote:
> On Sun, 2010-09-26 at 16:37 +0200, Wolfgang Denk wrote:
>> Dear Nishanth Menon,
>>
>> In message<4C9F3E4F.3040403 at gmail.com>  you wrote:
>>>
>>>> I think you are referring to SDRAM initialization. Yes, it is assumed
>>>> that SDRAM initialization(at least the DMM part of it) is done before
>>>> the call to sdram_size(). The right location for this seems
>>>> to be the initial part of sdram_init().
>>>
>>> thanks for the clarification.. NOR boot is usually going to have initial
>>> part in XIP ->  we'd traditionally relocate to SDRAM before the call to
>>> sdram_size() happens.
>>
>> Yes, this was the way how many ARM boards id, and this is what I'm
>> trying to explain: this is WRONG.
>>
>> SDRAM configuration must be done while still running from NOR, i. e.
>> before relocation. Only then free reconfiguration, auto-sizing etc. is
>> possible.
>
> I'll make sure that this is done properly when(if?) a patch series for
> an OMAP4 board with NOR boot is prepared.
>
> Getting back to the subject patch, though :-)
>
> This patch fixes a bug in the current Panda board support in rc2.
> Without this patch U-boot will return an erroneous size for available
> RAM.  We should consider it for inclusion as soon as practical.
I tend to agree, I might rather have my panda functioning properly and 
improve the location of sdram_size read at a later point of time -> for 
cleanups, we should probably start with the mux stuff..

That said, can we compromise by adding a FIXME: comment so that we dont 
really forget to fix it later on?

Regards,
Nishanth Menon


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