PCI-PCI bridge scanning broken on 460EX

[Stef van Os]

Hello Felix,

I had a problem similar to this on the 440GX, the PCI code was not
sending type 1 transactions when scanning behind bridges. Perhaps you
could try this:

Index: linux/arch/powerpc/sysdev/ppc4xx_pci.c
===================================================================
--- linux/arch/powerpc/sysdev/ppc4xx_pci.c      (revision 26)
+++ linux/arch/powerpc/sysdev/ppc4xx_pci.c      (revision 27)
@@ -569,7 +569,7 @@
        hose->last_busno = bus_range ? bus_range[1] : 0xff;

        /* Setup config space */
-       setup_indirect_pci(hose, rsrc_cfg.start, rsrc_cfg.start + 0x4,
0);
+       setup_indirect_pci(hose, rsrc_cfg.start, rsrc_cfg.start + 0x4,
PPC_INDIRECT_TYPE_SET_CFG_TYPE);

        /* Disable all windows */
        writel(0, reg + PCIX0_POM0SA);



With kind regards / Met vriendelijke groet,

Stef van Os

Prodrive B.V. 


-----Original Message-----
From: linuxppc-dev-bounces+stef.van.os=prodrive.nl at lists.ozlabs.org
[mailto:linuxppc-dev-bounces+stef.van.os=prodrive.nl at lists.ozlabs.org]
On Behalf Of Benjamin Herrenschmidt
Sent: zondag 10 januari 2010 22:32
To: Felix Radensky
Cc: linuxppc-dev at ozlabs.org; Stefan Roese; Feng Kan
Subject: Re: PCI-PCI bridge scanning broken on 460EX


> OK, I'll try writing byte by byte. The funny thing is the u-boot also 
> writes the same value to PCI_PRIMARY_BUS register and it doesn't cause

> reset.

Maybe the bridge doesn't want to be programmed more than once on these
registers ? In any case, that's very very fishy.... I wonder if the
bridge is causing a PCI reset -upstream- (which would really be a weird
thing to do) and the 460 is turning that into a system reset ? Check if
there are ways to control how the 460 reacts to PCI resets...

In any case, it looks like a fucked up bridge to me. I don't suppose
you've seen anything in the bridge data sheet or errata sheet that could
explain what it's doing ?

Cheers,
Ben.


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