Re: PCI BAR initialisation..?

I have mpc107 pci-host bridge.
motherboard is sandpoint + mcp750 processor.
pci_config_access method is indirect and config_address is 0xfec00000
config_data is 0xfee00000 rather than 0xcfc and 0xcf8.

i wonder if it would have been a case of memory reordering in that case
In bios how can we always believe on resource assignment of devices.
does it just a matter of chance that when we assign through bios this
reordering issue doesn't affect us..



Paul Mackerras wrote:

ashish anand writes:

quoted

But by any chance if somebody has come across a random feature of pci BAR.
that is if you write the required pci addresses in BAR after writing 0xffffffff and
reading it back , and to confirm if the actual value has reached the BAR , we read it again
but then it returns funny values.

more surprisingly if i move the code in some other function then everything behaves correctly.
I am more then sure that nothing relevant is happening betwen two places.

Hmmm, that sounds like maybe the config space reads and writes are
getting reordered, which would be a Bad Thing.

What sort of PCI host bridge does your system have?

If you place an mb() call after each pci config read or write, does
that fix the problem?

Paul.

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