[coreboot] [patch 16/16] Ranges unavailable for PCI BARs should bemarked as reserved in the E820 memory map, in case the OS wants to change the BARs.

[Tobias Diedrich]

Scott Duplichan wrote:
> From: Tobias Diedrich
> ]Linux also needs the MMCONF area to be reserved either in E820 or
> ]as an ACPI motherboard resource or it will not enable MMCONFIG
> ]and the extended pcie configuration area will be unaccessible:
> ]
> ]This patch adds the IORESOURCE_RESERVE flag to the APIC and MMCONF
> ]resource flags to do this.
> ]I also added a new resource for the mapped bios rom area just below 4GB.
> ]I'm not sure if the choice for the index parameter of new_resource()
> ]is correct though.
> ]Note that the bios rom decode is enabled in
> ]src/southbridge/via/vt8237r/vt8237r_early_smbus.c
> ]for the whole 4MB area (even though the comment says 1MB).
> 
> Thank you Tobias. To be even more conservative, the upper 5 MB of the
> first 4GB can be reserved for flash memory. This is because many LPC
> flash chips place the jedec ID register of the boot device at address
> ffbc0000.

I think that probably doesn't apply here, since the LPC flash
shouldn't get chip-select outside the selected area.
However src/southbridge/via/vt8237r/bootblock.c (which I had missed
because I got my board to work without touching this file)
says its actually 8MB big for VT8237A and VT8237S.

-- 
Tobias						PGP: http://8ef7ddba.uguu.de