PCI endianess

Benjamin Herrenschmidt benh at kernel.crashing.org
Wed Sep 4 04:09:36 EST 2002


>>as far as I know, the PCI bus is little endian, even on big endian
>machines.
>>Is this true for RS6000 (44p/270) too ?
>
>Yes, even on RS6K machines its little endian.
>You should write to PCI mapped register in little endian byte order.

Which should be done with the {read,write}{b,w,l} accessors in
asm/io.h which are supposed to do the byteswapping & IO barriers
for you on big endian archs.

Ben.


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