Access to PCI Expansion ROMs on PPC

[Robin H. Johnson]

On Sun, Nov 25, 2007 at 08:30:58AM -0500, Jon Smirl wrote:
> I don't know PPC at this low of level but it may be a problem with non
> word-aligned access to memory. I thought readb() was supposed to work
> on all archs and alignment issues are handled inside readb(). Also,
> the readw() may have an endian bug.
I was looking around for a description of the ROM layout, and instead I
found this: http://developer.apple.com/technotes/tn/tn2000.html
It was relevant because it explicitly mentioned enabling the
PCI_COMMAND_MEMORY bit in the PCI_COMMAND register, which is NOT present
in any path of the sizing code.

By doing:
# dev="/sys/devices/pci0001:00/0001:00:03.0/0001:06:00.0/"
# echo 1 >${dev}/enable
# echo 1 >${dev}/rom
# cat ${dev}/rom >rom
The ROM is successfully returned for two of my 3 cards.
Namely, both of the ones containing x86 BIOS (sata_sil24, ATI X700).
The X1900 does still not return any ROM.

So the pci-sysfs.c/rom.c code path needs to change to enable the device
somewhere if it was not enabled before (and presumably disable
afterwards for suspend/resume?).

I broke my testing kernel temporarily, so I need a bit more testing to
see why the X1900 did not return a ROM. More on that in a couple of
hours.

-- 
Robin Hugh Johnson
Gentoo Linux Developer & Infra Guy
E-Mail     : robbat2 at gentoo.org
GnuPG FP   : 11AC BA4F 4778 E3F6 E4ED  F38E B27B 944E 3488 4E85
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 321 bytes
Desc: not available
URL: <http://lists.ozlabs.org/pipermail/linuxppc-dev/attachments/20071125/24baaea2/attachment.pgp>