[U-Boot] [RFC] odroid DTB support

[Przemyslaw Marczak]

Hi Tom, Guillaume,

On 10/13/2015 09:37 AM, Guillaume Gardet wrote:
>
>
> Le 12/10/2015 16:24, Tom Rini a écrit :
>> On Mon, Oct 12, 2015 at 10:54:04AM +0200, Guillaume Gardet wrote:
>>> Hi,
>>>
>>>
>>> Le 12/10/2015 01:45, Tom Rini a écrit :
>>>> On Fri, Oct 09, 2015 at 02:35:24PM +0200, Guillaume Gardet wrote:
>>>>> Le 09/10/2015 14:23, Przemyslaw Marczak a écrit :
>>>>>> Hello Guillaume,
>>>>>>
>>>>>> On 10/09/2015 02:11 PM, Guillaume Gardet wrote:
>>>>>>> Hi Przemyslaw,
>>>>>>>
>>>>>>> I would like to add DTB support for odroid board to be able to boot
>>>>>>> upstream kernel easily.
>>>>>>>
>>>>>>> I see 2 ways to do it:
>>>>>>> * Add CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG support to set
>>>>>>> 'board_rev'
>>>>>>> and 'board_name' env vars. Then, you need a 'findfdt' script to
>>>>>>> check
>>>>>>> 'board_rev' and set fdtfile accordingly (as done for OMAP4 panda
>>>>>>> board)
>>>>>>> * Set fdtfile name directly (as done for rpi or igep00x0).
>>>>>>>
>>>>>>> What would you prefer?
>>>>>>>
>>>>>>>
>>>>>>> Guillaume
>>>>>>>
>>>>>>>
>>>>>> Is, that the reason of adding the boot script by your last patches?
>>>>> No, we need a boot script, because this is the way we boot our
>>>>> openSUSE images (we boot with an initrd and some special bootargs).
>>>> Hang on, exynos stuff uses the generic distro hooks.  Can you take a
>>>> look at doc/README.distro and see what openSUSE can hook into / provide
>>>> some feedback on what needs doing?  Thanks!
>>> This is true for odroid XU3 (Exynos5 based) but Odroid U3/X2 (Exynos4
>>> based) has no generic distro hooks at the moment.
>> No, exynos-common pulls in generic distro.  And in the event of boards
>> that do not the answer is to pull in the generic distro framework.
>
> It seems that exynos-common includes only "config_distro_defaults.h",
> not "config_distro_bootcmd.h".
> And "config_distro_bootcmd.h" is needed for generic distro boot flow. Am
> I missing something?
>
> Guillaume
>
>

Tom,
it's true that, exynos5-common.h defines the CONFIG_EXTRA_ENV_SETTINGS, 
which provides "BOOTENV".
Odroid XU3 redefines CONFIG_EXTRA_ENV_SETTINGS, but in the fact it uses 
the same settings, appended by some private env variables.

Guillaume,
You're right, Exynos4 boards doesn't use the generic distro boot 
commands. And each board defines CONFIG_EXTRA_ENV_SETTINGS.

All boards works with the mainline kernel by default, so it's not a high 
priority for us to switch it to common env, but will do this soon.

You can check the bootscript example in the directory:
  board/samsung/common/bootscripts/

As temporary, your patch for Odroid can be applied to support the 
boot.scr, but anyway it support mainline kernel and probably can boot 
Ubuntu images.

Some mainline release of U-Boot is used for Arch Linux images for Odroid 
U3, you can check the changes for ARCH here:

https://github.com/archlinuxarm/PKGBUILDs/blob/master/alarm/uboot-odroid/0001-arch-linux-arm-modifications.patch

So if you need write custom boot.scr, maybe this will help you.

One more thing, if you need append the bootargs for your kernel, then 
you can set the $opts variable which is always appended to bootargs.

Best regards,
-- 
Przemyslaw Marczak
Samsung R&D Institute Poland
Samsung Electronics
p.marczak at samsung.com