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

[Ryan Harkin]

On 10 January 2017 at 16:58, Alexander Graf <agraf at suse.de> wrote:
> 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.

Thanks for confirmation.


> 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.
>

I look forward to living in this ideal world the EDK2 and kernel
communities promised me several years ago ;-)

> Alex
>