[coreboot] Add coreboot storage driver

[Andrey Petrov]

Hi,

On 02/13/2017 10:22 AM, Timothy Pearson wrote:

> <snip>
>> For [2] we have been working on prototype for Apollolake that does
>> pre-memory MPinit. We've got to a stage where we can run C code on
>> another core before DRAM is up (please do not try that at home, because
>> you'd need custom experimental ucode).
>
> In addition to the very valid points raised by others on this list, this
> note in particular is concerning.  Whenever we start talking about
> microcode, we're talking about yet another magic black box that coreboot
> has no control over and cannot maintain.  Adding global functionality
> that is so system specific in practice as to rely on microcode feature
> support is not something I ever want to see, unless perhaps the relevant
> portions of the microcode are open and maintainable by the coreboot project.

I am just talking about BIOS shadowing. This is a pretty standard 
feature, just that not every SoC implement it by default. Naturally, we 
would be only adding new code if it became publicly available. I believe 
shadowing works on many existing CPUs, so no, it is not "use this custom 
NDA-only ucode" to get the stuff working.

Andrey