[U-Boot] [PATCH v2 08/10] tegra20: add u-boot.t2 target

[Stephen Warren <swarren@wwwdotorg.org>]

On 06/06/2012 01:53 PM, Tom Warren wrote:
> Allen,
> 
>> -----Original Message-----
>> From: Allen Martin [mailto:amartin at nvidia.com]
>> Sent: Wednesday, June 06, 2012 12:37 PM
>> To: Stephen Warren
>> Cc: Tom Warren; sjg at chromium.org; u-boot at lists.denx.de
>> Subject: Re: [PATCH v2 08/10] tegra20: add u-boot.t2 target
>>
>> On Wed, Jun 06, 2012 at 09:48:23AM -0700, Stephen Warren wrote:
>>> On 06/05/2012 03:20 PM, Allen Martin wrote:
>>>> Add target for tegra20 u-boot image.  This is a concatenation of
>>>> tegra spl and normal u-boot binaries.
>>>
>>>> diff --git a/board/nvidia/seaboard/config.mk
>>>> b/board/nvidia/seaboard/config.mk
>>>
>>>> +PAD_TO=0x00108000
>>>
>>> Oh crap, does this mean that we have to start flashing the combined
>>> u-boot.t2 at 0x8000 (IIRC the start address of the SPL in an earlier
>>> patch) instead of 0x108000? That would cause all kinds of problems. If
>>> that is the case, can we move the SPL to the existing 0x108000, and
>>> bump the regular U-Boot up a bit to make space? If that isn't the
>>> case, could you please explain exactly how the SPL memory layout etc.
>> works for me?
>>> Thanks.
>>
>> The addresses are arbitrary, I picked 0x8000 for the SPL to preserve the
>> existing 0x108000 for the normal u-boot but it doesn't have to be that way.
>> The only requirement is that the SPL needs to know the address of the normal
>> u-boot at compile time because it doesn't have any smarts to look for it.
>>
>> I'll move the SPL to 0x108000 and the normal u-boot to 0x208000 if that
>> sounds more acceptable.
> The current flash tools everyone is using expect to flash U-Boot to 0x0108000 (on T20). This works with the non-SPL (current) upstream U-Boot for Tegra, and should continue to work for any new SPL Tegra U-Boot, so that people can use the same flash tools for either build.
> 
> Note that the above statement assumes we'll still be able to build either a 'normal' non-SPL build of Tegra U-Boot and a SPL build with your patchset, at least in the interim while we're testing/reviewing these major changes.

I assume that once a board is converted to SPL, you always use a
matched/concatenated pair of SPL+non-SPL, i.e. never SPL on its own or
non-SPL on its own?

But that does bring up one point - boards which haven't yet converted to
SPL need to still build/link for the original 00108000 address, so the
addresses need to depend on config data.

Either that, or just convert all boards at once?