[coreboot] [PATCH] Istanbul support

Ed Swierk eswierk at aristanetworks.com
Tue Apr 13 00:30:08 CEST 2010

On Mon, Apr 12, 2010 at 3:28 AM, Arne Georg Gleditsch
<arne.gleditsch at numascale.com> wrote:
> My only remaining real issue is that parts of the nvidia mcp55 init code
> will not run properly using mmconf.  The offending line is
>  RES_PCI_IO, PCI_ADDR(0, 1, 0, 0x78), 0xC0FFFFFF, 0x19000000,
> which causes the operations
>  pci_read_config32: 00010000:0078: 20040000
>  pci_write_config32: 00010000:0078: 19040000
> the second of which never returns when executed using mmconf.  I'm
> speculating that this might be related to missing HT responses or
> something due to bus reconfiguration.  As far as I can tell the device
> being targeted here is 10de:0364 (ISA bridge: nVidia Corporation MCP55
> LPC Bridge).
> Anoyone familiar with the mcp55 who can shed some light on what this
> write is supposed to accomplish and perhaps also on why it succeeds
> using the IO config mechanism when mmconf fails?

That write has always caused a hang on Arista boards, even using plain
IO accesses. I have no idea what it's supposed to do, but we've left
it commented out with no apparent ill effects.

(Which reminds me that I need to port our patches to a modern version
of Coreboot one of these days...)


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