MPC8360 : PCI resource allocate error
Kumar Gala
galak at kernel.crashing.org
Wed Feb 7 01:51:43 EST 2007
On Feb 5, 2007, at 6:51 PM, Russell McGuire wrote:
>
> I think I might be getting someplace on this debugging of the PCI
> slots.
>
> I solved the erratic SLOT 3 issue, it was a hardware problem. A net
> was
> unconnected, I should shoot the designer. Anyway, this was fixed
> that so all
> slots are 100% consistent.
>
> I think general issue is probably a setup problem with the PCI
> bridge chip.
> Though I do not know how U-boot and Linux set up the bridge.
>
> But after reading through the Bridge documentation, I have learned
> that each
> bus must have the memory map declared in it, for all three memory
> spaces.
> I.e. the base and the upper limit for each mem, mmio, and IO space.
>
> When I boot into Linux, with PCI cards plugged in, and I read these
> registers it looks as if the base address is correct, but the upper
> limit is
> actually set one byte below the base address. To me this effectively
> prevents all access to the memory region, halting it at the bridge
> chip.
> Would explain why the only region I can seem to read is the
> configuration
> space.
>
> I guess the question is, does Linux only enable these ranges if a
> card is
> actively using them. Or is BIOS supposed to have these enabled
> before the OS
> gets access to the bridge?
In theory Linux should be able to handle this, in practice its easier
to have u-boot setup the bridges.
I'd ask around on the u-boot list about how to use the u-boot
mechanisms to preconfigure devices (if its not obvious from the code).
- k
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