Re: Status of PCI-PCI bridge on UMAX S900

[Chas Williams <chas@cmf.nrl.navy.mil>]

since i also have a umax/s900 i am fairly interested in getting this
working.  looking at the results from a dump-device-tree, i see that
a board on the other side of the bridge has the following properties:

/bandit@F2000000/pci-bridge@F/ADPT,2930CU@1
PROPERTIES:
vendor-id               00009004
device-id               00005078
revision-id             00000003
class-code              00010000
interrupts              00000001
min-grant               00000004
max-latency             00000004
subsystem-vendor-id     00009004
subsystem-id            00007850
devsel-speed            00000001
fast-back-to-back
AAPL,slot-name          C1
fcode-rom-offset        00000000
name                    ADPT,2930CU
device_type             scsi
model                   ADPT,1686806-04
compatible              ADPT,AIC-7856
ADPT,fcode-version      342E3000
ADPT,fcode-date         31382D4A 616E2D31 39393900
reg                     00010800 00000000 00000000  00000000 00000000
                        02010814 00000000 00000000  00000000 00001000
                        02010830 00000000 00000000  00000000 00010000

indeed, the 'interrupts' property is 1, which i believe means that the
board has 1 interrupt, not that its interrupt is one.  ben said, 'when it
can't find it ["AAPL,interrupts"], it looks for the parent', so examining
the bridge itself:

/bandit@F2000000/pci-bridge@F
PROPERTIES:
vendor-id               00001011
device-id               00000021
revision-id             00000001
class-code              00060400
devsel-speed            00000001
fast-back-to-back
AAPL,interrupts         00000019
AAPL,slot-name          C1
name                    pci-bridge
device_type             pci
reg                     00007800 00000000 00000000  00000000 00000000
#address-cells          00000003
#size-cells             00000002
ranges
bus-range               00000001 00000001
power-consumption       007270E0 007270E0

i am not a pci expert by any means, but i am guessing that all the slots
on the other side of this bridge share the interrupt, 0x19.  this seems like
a bad idea, but its probably not that big a deal for graphics or low
performance (10mb ethernet, usb, etc) boards.  so i guess your patch should
be more like:

...
    ip = (int *) get_property(np, "AAPL,interrupts", &l);
+   /* JSL: HACK FOR UMAX S900 PCI-PCI BRIDGE (DECchip 21052) */
+   if (ip == 0 && np->parent != NULL)
+           ip = (int *) get_property(np->parent, "AAPL,interrupts", &l);
...

btw, looking at the device-tree on my g4, it looks each board on the other
side of the bridge is assigned an individual irq.