[coreboot] K8 and Fam10 CAR
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).
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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