[U-Boot] [RFC PATCH] arm: bootm: Boot kernel with U-Boot's FDT blob

[Alexander Graf]

On 01/10/2017 05:47 PM, Ryan Harkin wrote:
> On 10 January 2017 at 16:35, Alexander Graf <agraf at suse.de> wrote:
>> On 01/10/2017 05:31 PM, york sun wrote:
>>> On 01/10/2017 05:02 AM, Alexander Graf wrote:
>>>> On 01/10/2017 01:58 PM, Michal Simek wrote:
>>>>> U-Boot configured via DTB can use the same DTB for booting the kernel.
>>>>> When OF_CONTROL is used fdtcontroladdr is setup and can be use for boot.
>>>>>
>>>>> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
>>>>> ---
>>>>>
>>>>> Didn't check if there is any side effect or not but it looks weird when
>>>>> you have DT driver u-boot that you have to load dtb again.
>>>> I agree, and I think it's very reasonable to try and use the same device
>>>> tree for U-Boot and Linux.
>>>>
> Would this prevent the user loading a DTB into ram and using bootm to
> over-ride the built-in DTB?
>
> I have a background task to refactor u-boot support for ARM Ltd
> boards. One of many options I was considering was to have a minimal
> DTB to configure the platform with only the nodes needed for u-boot.
> The ARM Ltd device trees fluctuate so much, I wouldn't be able to
> commit to one DTB that will work forever...

No, it's only meant as a fallback when no manual device tree is 
provided. In an ideal world however, device trees are static and 
complete, so you could just put a final dt into U-Boot and have it 
propagated all the way through.

Alex