On Mon, 03 Mar 2008 18:02:33 -0600
Hollis Blanchard <[EMAIL PROTECTED]> wrote:
> I'm having two problems with PCI interrupts as described in bamboo.dts.
> Here is are the properties in question:
>
> /* Bamboo has all 4 IRQ pins tied together per slot */
> interrupt-map-mask = <f800 0 0 0>;
> interrupt-map = <
> /* IDSEL 1 */
> 0800 0 0 0 &UIC0 1c 8
>
> /* IDSEL 2 */
> 1000 0 0 0 &UIC0 1b 8
>
> /* IDSEL 3 */
> 1800 0 0 0 &UIC0 1a 8
>
> /* IDSEL 4 */
> 2000 0 0 0 &UIC0 19 8
> >;
>
>
> First, the 440EP[1] and Bamboo[2] user manuals indicate that PCI IRQ 0-3
> -> board IRQ 2-5 -> UIC IRQ 25-28. However, the device tree has that
> reversed, so PCI IRQ 0 appears as UIC IRQ 28 (0x1c).
Actually, the device tree is right. I got annoyed with myself for not
knowing how this works so I went and figured it out.
2000 0 0 0 is device #4. According to the specs, device #4 has AD(14)
asserted during type 0 configuration. Looking at the board schematics,
PCI slot 0 has it's IDSEL line tied to AD(14). So:
dev #4 -> PCI 0 -> board IRQ 2 -> UIC IRQ 25.
which is exactly what the device tree has.
> Second, the sensitivity seems to be wrong. All these interrupts have the
> sensitivity encoded as 8, which means "high to low edge" in the OpenPIC
> binding. Now, 440EP has a UIC, rather than an OpenPIC, but there is no
> UIC binding AFAICS.
There isn't. It uses the sense numbers from linux/irq.h. Which means
8 is level, low. This matches exactly what the board manual says for
IRQ2-5 on page 69.
> When I change the 8 to a 4 ("active high level"), I see the proper
> values in the UIC polarity register, and PCI interrupts start working in
> KVM.
That's odd.
> Is anybody using Bamboo PCI support right now? Does it actually work?
I plugged in an old 3Com ethernet card tonight. Slot 0. It was
assigned dev #4 IRQ 25. Using the device tree as-is, I could see
interrupts happening in /proc/interrupts but ethernet traffic failed.
Then I changed the sense level to 4 as you suggested, and my card hung
hard on the first ethernet traffic. I've no idea if we're dealing with
a crappy card or a crappy driver but the device tree seems to be
working ok. If I can find a different card to test with I will.
Ben, do you have any input here?
josh
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-dev
