Re: Walnut PCI bridge can't be detected

I was puzzled by this for a while. Then I saw this code while debugging
PCI on my custom board:
In ppc405_pci.c, there is ppc4xx_exclude_device function:

static int
ppc4xx_exclude_device(unsigned char bus, unsigned char devfn)
{
/* We prevent us from seeing ourselves to avoid having
* the kernel try to remap our BAR #1 and fuck up bus
* master from external PCI devices
*/
return (bus == 0 && devfn == 0);
}

With this function there, there is no way you are going to see the
bridge, even your driver does the scan itself. I had to write my own
pci_read_config_<size> function to just to be able to read the bridge
configration.

Cheers,

Xiaoshan

Jacky Lam wrote:

Dear all,

   Concerning my pervious posts about the problem on receiving interrupt
from PCI cards. I guess it is the problem of PCI bridge..(at least I think
it is related). Watching the old post in this list, someone post the boot
log of Walnut board here long time ago. The boot log contians a line to
detect PCI bridge just after the line"PCI: Probing PCI hardware". However,
the current devel tree running on Walnut doesn't have this.

   Also, under /proc/bus/pci and /proc/pci, I can't see any information
about the brdige.

   Moreover, I find that there is a minor different on a bit in my ES1371
card on Walnut from that on PC. On PC, ES1371 seems will capture an "Slave
interrupt controller" event just after bootup. But on Walnut, the event will
become "Slave DMA controller".

   I think these all differents are rooted from some miss configuration
about PCI in u-boot or kernel early  initialization. I am not familiar with
PCI. Hope someone here knows what is happening and gives me some idea on how
to fix that.

   Thanks so much.

Best regards,
Jacky

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