PCI bridge devices questions

[Marty Leisner]

I have to write some code to insert a non-standard bridge
(it identifies itself as bridge-other, but it functions
as a pci-pci bridge).

I'm going to be using 2.4.2x and eventually 2.6.x for intel
and ppc...

In the pci_dev structure (for 2.4.29)
there's
(in include/linux/pci.h)

00355 #define DEVICE_COUNT_RESOURCE   12
00410         struct resource resource[DEVICE_COUNT_RESOURCE]; /* I/O and memory regions + expansion ROMs */

We also have:
00431 /*
00432  *  For PCI devices, the region numbers are assigned this way:
00433  *
00434  *      0-5     standard PCI regions
00435  *      6       expansion ROM
00436  *      7-10    bridges: address space assigned to buses behind the bridge
00437  */
00438 
00439 #define PCI_ROM_RESOURCE 6
00440 #define PCI_BRIDGE_RESOURCES 7
00441 #define PCI_NUM_RESOURCES 11

Now where my confusion sets in:
	1) PCI_NUM_RESOURCES + 1 == DEVICE_COUNT_RESOURCE 
Why?
	2) I understand the first 6 regions (standard) and the expansion rom) --
	   why 5 more?  
	3) I've only seen instances of 3 bus regions used -- IO, MEM prefetch,
		MEM nonprefetch -- are they order dependent?
		
	4) would it make more sense to have seperate arrays?  One of for the 
	device resources, one for the bridge resources?

Thanks...

Marty Leisner
leisner@xxxxxxxxxxxxxxxx
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