[coreboot] Does ChromeOS-EC have to boot ChromeOS?

[David Hendricks]

On Tue, Apr 26, 2016 at 12:20 AM, Zheng Bao <fishbaoz at hotmail.com> wrote:

> <https://chromium.googlesource.com/chromiumos/platform/ec>
> <https://chromium.googlesource.com/chromiumos/platform/ec>
> https://chromium.googlesource.com/chromiumos/platform/ec
>
> Hi, Stafan & All,
> I am trying to build a platform which uses AMD APU + EC.
>
> My goal is let EC
> 1. give the power sequencing logic to APU
> 2. play as a generic EC which has features like keyboard, UART.
>
> Currently, I don't have plan to boot chrome OS yet.
>
> So I need you guys give me some advice.
> Does chromeOS-EC meet my requirement?
>

Yes, it should. However there is only support for a limited number of ECs.

Is it OK if I don't boot chromeOS?
>

Yes. Most of the verified boot logic is in the host firmware
(coreboot/depthcharge).

Is chromeOS-EC hard to master?
>

I'd say it's moderately difficult, but not bad. The mess of config #defines
can be frustrating (ctags and grep are infinitely useful) but the design
makes sense for something that is optimized for minimal code size and
reusability among different ECs.

I don't know how easy/difficult it is compared to other EC firmwares. I
suggest using ctags to walk thru the initialization code in common/main.c
to see how initialization is done, and also choose a specific board (with
your preferred EC) to study how GPIOs, interrupts, tasks, hooks, etc. are
used.

Try posting to chromium-os-dev at chromium.org. There are several EC
developers who read that list and can answer questions.

-- 
David Hendricks (dhendrix)
Systems Software Engineer, Google Inc.
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