[U-Boot] [PATCH 12/12] imx: ventana: switch to SPL

[Tim Harvey]

On Wed, May 7, 2014 at 1:29 PM, York Sun <yorksun at freescale.com> wrote:
> On 05/07/2014 01:27 PM, Tim Harvey wrote:
>> On Wed, May 7, 2014 at 9:14 AM, York Sun <yorksun at freescale.com> wrote:
>>> On 05/06/2014 04:35 PM, Tim Harvey wrote:
>>>> On Tue, May 6, 2014 at 12:11 PM, Jeroen Hofstee <dasuboot at myspectrum.nl> wrote:
>>>>> Hello Tim,
>>>>>
>>> <snip>
>>>>>
>>>>> Since Crt0.S already created gd on the stack before calling
>>>>> board_init_f, can't the assignment of gd not simply be removed?
>>>>> Is there anything special about gdata?
>>>>>
>>>>> Regards,
>>>>> Jeroen
>>>>>
>>>>>
>>>>
>>>> Jeroen,
>>>>
>>>> That does make sense, but what I find is that York's ocmmit
>>>> dec1861be90c948ea9fb771927d3d26a994d2e20 requires that gd be blanked
>>>> and its not. This causes bus_i2c_init to skip its initialization
>>>> because p->base is not zero.
>>>>
>>>> York, does this make sense? Your patch creates a dependence on
>>>> gd->srdata being blank which isn't the case with the SRAM when booting
>>>> from the IMX6 boot rom.
>>>>
>>>
>>> GD should be cleared (zeroed). Then we don't have this problem. Whoever sets up
>>> gd (board_int_f, cpu_init_f, or others) should make sure gd is cleared. Why
>>> isn't it the case for IMX6 boot rom?
>>>
>>> York
>>>
>>
>> York,
>>
>> crt0.S is mapping gd to where the SPL stack pointer is defined, which
>> is where Freescale says its stack pointer is for its firmware BOOT
>> ROM, so its initial data will be dependent on what the BOOT ROM did.
>>
>> I think the right solution is to have crt0.S zero it out.
>>
>
> Either crt0.S, or somewhere before gd is used for the first time. Can it be done
> in board_init_f()?
>
> York
>
>

It makes more sense to do it in crt0.S so that all boards don't have
to do it and can make the assumption that it is cleared.

Tim