Re: [coreboot] Microcode problem with Braswell CPU

[Alexander Böcken]

Hi all,

I made a discovery yesterday that somehow solves my initial problem:

The function bootblock_cpu_init() (/src/soc/intel/braswell/bootblock/bootblock.c) contains a call to enable_rom_caching(). If I remove this call then TempRamInit returns successfully and coreboot is able to call cache_as_ram_main(). Hence, TempRamInit must have returned a valid (cache) memory range and I have a stack now.

I don’t yet understand the implications of this “fix”, nor how it relates to TempRamInit. Maybe, someone from Intel can shed light on this. Meanwhile I’m learning about memory type range registers (MTRRs) because they are being accessed in enable_rom_caching().

Also, cheng, can you confirm that this works for you?

Best regards,
Alex