[coreboot] Resource Allocation discussion

Marc Jones marcj303 at gmail.com
Fri Dec 5 23:08:19 CET 2008

On Wed, Dec 3, 2008 at 11:43 AM, Myles Watson <mylesgw at gmail.com> wrote:

> A question before the code:
> 1. Can anyone enumerate all the fixed resources that should be included in
> Currently I have:
> - DRAM (first 640K and 0xc0000-TOP-768K) Is this necessary?
> - I/O first 0x400 in southbridge
> - VGA 0xa0000-0xc0000
> - APIC at 0xfec00000 and 0xfee00000
> - ROM at 0xfff80000

This looks normal. You could put the first 0x1000 in the SB IMO.

> Side note: Only the lowest and highest fixed addresses matter in my code.
> The others get ignored.  I think it's too much pain to try to interleave
> them to use the space between 0xfee00000 and 0xfff80000, for example.

This is probably ok for a normal system. There is a problem with this
if a device is already setup and should be treated as fixed but if
that is the case it should be seup in the dts....

>     /* Initialize constraints to maximum size. */
>     limits.pref.base = 0;
>     limits.pref.limit = 0xfffffffffffffffULL;
>     limits.io.base = 0;
>     limits.io.limit = 0xfffffffffffffffULL;
>     limits.mem.base = 0;
>     limits.mem.limit = 0xfffffffffffffffULL;

The limit for memory and prefetch should be the same since they are in
the same address space. For mem.base I assume it gets set from TOM
(for K8) somehow?


More information about the coreboot mailing list