[U-Boot] [RFC PATCH 6/8] omap3_beagle: add nand_spl support

[John Rigby]

On Sat, Jan 8, 2011 at 1:33 AM, Aneesh V <aneesh at ti.com> wrote:
> John,
> On Saturday 08 January 2011 12:16 PM, John Rigby wrote:
>>
>> On Fri, Jan 7, 2011 at 11:33 PM, Aneesh V<aneesh at ti.com>  wrote:
>>>
>>> Hi John,
>>>
>>> On Tuesday 28 December 2010 06:17 AM, John Rigby wrote:
>>>>
>>>> Signed-off-by: John Rigby<john.rigby at linaro.org>
>>>> +
>>>> +void board_init_f(unsigned long bootflag)
>>>> +{
>>>> +       nand_boot();
>>>> +}
>>>> +
>>>
>>> I see that you have added a call to nand_boot() in start.S too.
>>> Which is the intended one?
>>> If we jump to nand_boot() here bss will not be cleared, right?
>>>
>>> Also, I see potential issues in start.S that will prevent bss setup for
>>> PRELOADERs. I will correct these in my patch.
>>>
>>> Best regards,
>>> Aneesh
>>>
>>
>> The call to nand_boot in board_init_f makes sense for platforms where
>> the spl code does not need to be relocated because it has been loaded
>> into SRAM by a mask boot rom.  The later nand_boot called from start.S
>> is for the traditional nand_spl case where you are typically running
>> in a 4K nand controller buffer so the code needs to be relocated to
>> dram after dram init.
>>
>> Of course my only testing has been on OMAP3 which fits the first case.
>>  I'm not sure if the second case even matters.  The arm7 platforms I
>> know about all have rom boot loaders and large enough SRAM to run the
>> spl u-boot in (OMAP[34]) or have boot headers that can be used to init
>> dram before loading a full u-boot into dram (i.mx5[13]).
>>
>> Also, I was thinking that BSS would not be used in PRELOADERs but of
>> the large SRAM case it certainly would be useful to have BSS.
>>
>
> Agree. So, how about this?
> 1. Call relocate_code() in board_init_f() with destination address same
> as TEXT_BASE
> 2. start.S skips the relocation, clears the bss(this needs to be fixed)
> and calls board_init_r
> 3. Call nand_boot() in board_init_r
>
> This is what I am planning to do for OMAP4 preloader.
>
Sounds good to me.

Hopefully in the next couple of days I will have time to send a new
series of my own.  Then we need to combine the two.  So there is one
unified series for proposing for acceptance.

John