[U-Boot] ARM: sama5d2: Implement boot device autodetection

[Andreas Bießmann]

Hi Marek,

On 2016-05-03 13:04, Marek Vasut wrote:
> On 05/03/2016 10:52 AM, Andreas Bießmann wrote:
>> On Fri, Apr 22, 2016 at 09:56:21PM +0200, Marek Vasut wrote:
>>> Implement support for saving ARM register R4 early during boot using
>>> save_boot_params . Implement support for decoding the stored register
>>> R4 value in spl_boot_device() to obtain boot device from which the
>>> SoC booted. This way, the SPL will always load U-Boot from the same
>>> device from which the SPL itself booted instead of using hard-coded
>>> boot device.
>>> 
>>> This functionality is useful for example when booting 
>>> sama5d2-xplained
>>> from SD card, where by default the SPL would try loading the U-Boot
>>> from eMMC and fail. This is because eMMC is on SDHCI0 
>>> (BOOT_DEVICE_MMC1),
>>> while SD slot is on SDHCI1 (BOOT_DEVICE_MMC2) and the SPL was 
>>> hard-wired
>>> to always boot from BOOT_DEVICE_MMC1.
>>> 
>>> Signed-off-by: Marek Vasut <marex at denx.de>
>>> Cc: Andreas Bießmann <andreas.devel at googlemail.com>
>>> Cc: Wenyou Yang <wenyou.yang at atmel.com>
>>> 
>> 
>> Reviewed-by: Andreas Bießmann <andreas at biessmann.org>
> 
> I will eventually extend this to SAMA5Dx as this is quite helpful on
> upcoming board.

Let's do it for the next release. Hopefully this gets in with 2016.05 
... as always I'm really late for my pull request.

Andreas

> 
>>> ---
>>>  arch/arm/mach-at91/Makefile               |  2 +-
>>>  arch/arm/mach-at91/bootparams_atmel.S     | 18 ++++++++++++++++
>>>  arch/arm/mach-at91/include/mach/sama5d2.h | 12 +++++++++++
>>>  arch/arm/mach-at91/spl.c                  | 36 
>>> +++++++++++++++++++++++++++++++
>>>  4 files changed, 67 insertions(+), 1 deletion(-)
>>>  create mode 100644 arch/arm/mach-at91/bootparams_atmel.S