[U-Boot] [RFC] odroid DTB support

[Przemyslaw Marczak <p.marczak@samsung.com>]

Hello,

On 10/12/2015 10:54 AM, Guillaume Gardet wrote:
> Hi,
>
>
> Le 12/10/2015 01:45, Tom Rini a ?crit :
>> On Fri, Oct 09, 2015 at 02:35:24PM +0200, Guillaume Gardet wrote:
>>>
>>> Le 09/10/2015 14:23, Przemyslaw Marczak a ?crit :
>>>> 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.
>
> What we need:
> * Boot on boot.scr (mainly to define kernel name, initrd name and bootargs)

If you need some more, than the above, then using boot.scr is required, 
but if not, then U-Boot provides this all at default.

> * Use (pre-defined) fdtfile, or be able to define it manually if not
> already set (or not in sync with Linux kernel)
>
>
> Guillaume
>
>
>

For odroid_defconfig, the basic things are done automatically.

The variables:
- $fdtfile
- $boardname
are set automatically and are consistent with the mainline kernel file 
names, so for U3 the fdtfile is set as "exynos4412-odroidu3.dtb".
If you have u/zImage and fdtfile on the first partition(boot), then it 
just boot with defaults.
If you need some more features, then you can use multi config itb format.

The initrd is also loaded automatically.

All images must be stored on $boot partition

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