[Buildroot] [PATCH] linux: Introduce DTB's bootargs fixup feature

Maxime Coquelin mcoquelin.stm32 at gmail.com
Wed Mar 30 09:38:04 UTC 2016


Hi Thomas,

2016-03-30 0:11 GMT+02:00 Thomas Petazzoni
<thomas.petazzoni at free-electrons.com>:
> Hello,
>
> On Mon, 21 Mar 2016 13:53:50 +0100, Maxime Coquelin wrote:
>
>> > However, I am not entirely sure this is something we want to take in
>> > Buildroot. Indeed, your patch only allows to customize
>> > the /chosen/bootargs property, and not any other property of the Device
>> > Tree. If we want to do that via Config.in options, it suddenly becomes
>> > a lot more complicated.
>> Indeed, it will be difficult to extend it further than bootargs.
>> It works well for bootargs for two reasons:
>>  1- It is a generic property
>>  2- It is a string
>>
>> There could be other uses for DTB patching, such as MAC address assignment.
>> But I agree than doing this in Config.in makes no sense.
>
> Right.
>
>> > It is IMO even more important to do it this way since as of today, only
>> > one platform/board needs to adjust its bootargs this way. All other
>> > platforms have an ATAGs or DT compatible bootloader, where the bootargs
>> > customization is done via the bootloader, not via patching the DTB.
>>
>> Ok, For sure it can be done, but I wanted to propose a generic way of
>> doing this.
>> Indeed, this is something other platforms could potentially use, even
>> if not the case today.
>>
>> > Of course, let's see what others think.
>>
>> Agree.
>> If it is decided to do this as post-image script, I will be happy to
>> implement it.
>
> Nobody spoke up, so let's say we'll do it in a post-image script for
> now. host-dtc is already visible in menuconfig, so it can be enabled in
> a defconfig, and therefore it's just a matter of enabling it and write
> the appropriate post-image script.
>
> Do you want to write a patch on top of my series adding Cortex-M
> support?

Yes.
Will you apply your Cortex-M series soon on master branch?
I will propose a patch as soon as your series is available.

Regards,
Maxime


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