[coreboot] Microcode problem with Braswell CPU

[Alexander Böcken]

Hi Zoran,

thanks for checking back. I’m still on the issue (next to some other things), but haven’t made any progress yet. I also opened up a case at Intel Premier Support and tried to follow their suggestions (Case 00053422).

Anyway, I know the post_codes.h file. It defines POST_FSP_TEMP_RAM_INIT (0x90) which is the post code shown by coreboot just before it calls TempRamInit. Then TempRamInit shows 0x52. Intel suggested that this is a microcode problem (i.e. the microcode doesn’t match the CPU stepping or platform), however, I’m pretty sure that this is not the case. At least I’ve taken a look at the CPUID signature (which is 0x406C4) and the microcode header signature (which is 0x406C4). I also compared the platform ID bits from MSR 0x17 (which are 000, i.e. 1 << 000 = 1) with  the platform ID field of the microcode (which is also 1). The microcode update facilities are documented in Intel’s System Programming Guide (#325384).

I’m currently checking if coreboot is able to update the microcode while still in bootblock. There is a call to intel_update_microcode_from_cbfs() in /src/soc/intel/braswell/bootblock/bootblock.c. Maybe, there is something sticking out…

Regards,
Alex

Von: Zoran Stojsavljevic [mailto:zoran.stojsavljevic at gmail.com]
Gesendet: Montag, 25. Juli 2016 22:08
An: Alexander Böcken
Cc: coreboot at coreboot.org; york.yang at intel.com
Betreff: Re: [coreboot] Microcode problem with Braswell CPU

Hello Alex,

It is awhile... Opportunity just did struck (suddenly/plotzlich), so I am back!

While lurking around in Coreboot, trying to solve some "Mystery of digital Orga.ni.sms", I ran into very interesting file:
./src/include/console/post_codes.h

Coreboot tree I am using: [zoran at localhost coreboot-09.06.2016]$ git describe<CR>
4.4-455-g538b324

Maybe, it is worth looking into it. You tell us?

Zoran

On Tue, May 3, 2016 at 10:28 AM, Alexander Böcken <Alexander.Boecken at junger-audio.com<mailto:Alexander.Boecken at junger-audio.com>> wrote:
Hello Zoran,

again, thanks for your clues to this problem. I don't think post code 0x52 is about memory configuration. The post code appears when I call TempRamInit which is supposed to enable Cache-as-RAM. Real memory is initialized at a later call to FspMemoryInit. coreboot supplies the location of the microcode and a cachable region to TempRamInit. Additionally, there are some settings that can be applied to the FSP image with Intel's Binary Configuration Tool. I don't know if these are used during TempRamInit, but I'll try and fiddle around with them.

I agree, it would be helpful to have a list of post codes that can be output by FSP. Otherwise it's all speculation as what is wrong.

Regards,
Alex

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