Linux PowerPC, PPC4xx

[Benjamin Herrenschmidt]

On Wed, 2019-10-16 at 15:19 +0200, Carlo Pisani wrote:
> hi
> I am a student, I represent a group of friends running a couple of
> opensource projects(1), and we are lost with this(2) problem.
> 
> I wrote here(2) a couple of years ago, we are still working with
> kernel
> 4.11.0 and there is broken support for initializing the PCI.
> 
> The PCI initialization of the PPC405GP seems wrong and every
> kernel >= 2.6.26 is not able to correctly address the PDC20265
> 
> an interesting note is:
> kernel 2.6.26 can be compiled with arch=ppc and arch=powerpc
> 
> when compiled with arch=ppc the promise PDC20265 chip is correctly
> managed; while when compiled with arch=powerpc the PDC20265 is not
> correctly managed
> 
> any idea? advice? help? suggestion?
> a good place to discuss it?

On powermac we have a quirk to force these controllers into native
mode. You can try that.

Look for pmac_pci_fixup_pciata(). You could copy that to
powerpc/pci_32.c along with

DECLARE_PCI_FIXUP_EARLY(PCI_ANY_ID, PCI_ANY_ID, pmac_pci_fixup_pciata);

(maybe rename pmac to ppc) and remove the line that checks for
machine_is(powermac)

Cheers,
Ben.