[coreboot] K8 and Fam10 CAR

Marc Jones marc.jones at amd.com
Mon Aug 11 23:15:28 CEST 2008

Segher Boessenkool wrote:
>>> Don't APs also need to initialize DRAM? Or can the BSP do this
>>> "remotely" ?
>> APs should do it.
>> I'm getting a supermicro mainboard with 4 sockets and 128 GB memory,
>> and I want that done in parallel :-)
> In principle, the BSP can initialise multiple memory controllers
> in parallel as well.  Using multiple processors to do it is quite
> hard, esp. since you cannot do "normal" SMP stuff because memory
> isn't initialised yet; and you get all the "normal" SMP headaches
> as well obviously.
> If the memory init needs to access resources that it cannot access
> remotely (like, MSRs on x86), you have no choice but to use APs,
> of course.  This seems to be the case on FAM10h (but not on K8).
> Segher

Couldn't have said it better myself. :)

We do some message passing with the APIC registers to indicate when the 
APs have finnished their init. The init mostly consists of fid/vid setup 
and getting the APIC IDs set.


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Marc Jones
Senior Firmware Engineer
(970) 226-9684 Office
mailto:Marc.Jones at amd.com

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