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

[Stephen Warren <swarren@wwwdotorg.org>]

On 06/06/2012 04:00 PM, Allen Martin wrote:
> On Wed, Jun 06, 2012 at 12:57:05PM -0700, Stephen Warren wrote:
>> On 06/06/2012 01:53 PM, Tom Warren wrote:
>>>>
>>>> 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?
> 
> Yes, that's the intention.  Although I do have plans down the road for
> adding memory initialization to the SPL so I can use it for
> boot/flashing when in recovery mode and there's no BCT.  In the normal
> case they have to be used together.

How would that work; in the regular boot process, SPL would be linked to
e.g. 00108000 since the boot ROM will put it into SDRAM. However, in
recovery mode, code will be downloaded to the IRAM, so would have to be
linked to a different address, and hence the same SPL binary couldn't be
used. At that point, aren't we looking at:

* Regular boot SPL, which just sets up a few PLLs and jump-starts the A9s.
* Regular boot full-blown U-Boot to run on the A9s.
* Some third build t run from IRAM.

Or am I missing something?