Well not sure if this is really a problem, but it has me wondering which is the right direction to solve it.
I have an MPC8360E board, with PCI and have defined the following values:
PCI MEM = 0x8000_0000 set at 256MB
PCI MMIO = 0x9000_0000 set at 256MB
PCI IO = 0xF100_0000 set at 16MB
The PNP configuration of U-boot will of course read different memory maps of cards, and allocate memory for such.
When attempting to put a graphics card in the slot and use PNP configuration, the card auto-detects as two devices of 128MB each.
This of course consumes the entire PREFETCH space <it is a 256MB ATI card>.
Great this is correct, however, now when system steps down to the 2nd PCI bridge and attempts to allocate a small region space for the area, one would expect an error to be thrown since we are out of memory.
But instead it continues to allocate into the MMIO space, and we end up with something like this in the Configuration space of the PCI bridge.
PCI_MEM_BASE = 0x9001_0000
PCI_MEM_LIMIT = 0x9000_0000
The limit is lower than the BASE, and this entire region should be limited to 0x8FFF_FFFF anyway.
For now I have changed the location of the PCI_MEM to be at 0xA000_0000, above the MMIO space so that over allocations do not destroy the mappings of the MMIO space.
Has anyone else seen this problem?
-Russ