[U-Boot] [PATCH v2 15/27] x86: Integrate Tunnel Creek processor microcode

[Simon Glass]

Hi Bin.


On 9 December 2014 at 23:17, Bin Meng <bmeng.cn at gmail.com> wrote:
> Hi Simon,
>
> On Wed, Dec 10, 2014 at 2:09 PM, Simon Glass <sjg at chromium.org> wrote:
>> Hi Bin,
>>
>> On 9 December 2014 at 07:50, Bin Meng <bmeng.cn at gmail.com> wrote:
>>> Integrate the processor microcode version 1.05 for Tunnel Creek,
>>> CPUID device 20661h.
>>>
>>> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
>>> ---
>>>
>>> Changes in v2: None
>>
>> We are going to end up with microcode both in the device tree and in
>> an assembler include file.
>>
>> This seems unfortunate. I wonder if we can always put it in the device
>> tree, but then optionally also compile it into the image using a
>> symbol (as we do in dts/Makefile for CONFIG_OF_EMBED). This could be
>> done with fdtget to read the binary output of the property perhaps. I
>> haven't looked at it in detail though.
>>
>
> This will do for the embedded case, but it won't help for the separate dtb case.
>
>> Maybe this is too clumsy but it would be good to have it in one
>> format. Or maybe we should have a tool which can generate either
>> format.
>
> I don't think we are able to parse device tree in that early phase
> (before car_init), to get the microcode content from dtb. I know in
> some Intel processors, the microcode update are required before CAR
> initialization, as without the microcode update, the CAR
> initialization will fail.

Right, I meant that we could perhaps do this in the build system -
i.e. compile in the microcode after reading it from the device tree.

Not thrilled with the idea...

Regards,
Simon