[coreboot] Native init for AMD cards

[ron minnich]

On Mon, May 27, 2013 at 9:45 PM, David Hubbard
<david.c.hubbard+coreboot at gmail.com> wrote:

> 1. How hard would it be to import the kernel code into coreboot directly?
>

don't. You should do a lot of extraction using coccinelle. And even
then, there's lots of work to do. I hope to start commits next week
and hopefully this will provide some ideas.

> The ACPI init at the end could be skipped for a first attempt.

yeah.

>
> It would be some work to find the kernel APIs used in the radeon code and
> produce suitable glue for coreboot.

yes, do don't do that. The kernel APIs are not right for firmware.


> 2. Do coreboot developers have contact with the radeon driver developers? A
> little nudge from time to time could keep a project like this on track.

anyone?

>
> 3. It feels wrong to add so much code to coreboot.

So, don't add it. The i915 support is slowly boiling down to a few
hundred lines and that should be your goal. Also, the kernel uses
generic code to switch to device specific functions. That makes sense
for a kernel, because it boots on many chipsets and many vga devices.
It makes no sense for firmware, because we have so much we already
know -- what chipset, what vga, etc.. Remove generice code and create
device specific functions with a reasonable API.

> With 20/20 hindsight,
> this could be one of UEFI's downfalls, namely making the pre-boot
> environment into an entire kernel.

I've been saying this for 14 years ... :-)

But they are not listening of course. EFI is basically a not very good
OS that is wanting to be a boot loader. It never made much sense
technically but it seems to have done well politically.

>
> Is a modular approach better? A payload to modeset or some sort of driver
> model would be nice.

No, what's best is a simple set of functions with a simple API. See
superio for example. Or give it 2 more weeks and see what is coming
:-)

ron