MPC5200 PCI byte-swapping

Sylvain Munaut tnt at
Tue Jan 4 03:47:48 EST 2005

>Thanks.  I had an older manual that didn't spell it out so
>I've been trying to interpret the PCI sections for some other
>82xx family parts, and it appears that they do NOT do this
>byte lane swapping, so this make the 5200 non-standard in
>this regard, which is unfortunate.  If I'm understanding this
>right, one would have to have different drivers for a PCI
>device on a 5200 and an 8270, for instance.
Mmmm ...
Still I use the intel eepro driver without problems or modifications.
As long as the driver uses the proper readl/writel that should do
it or am I mistaken ?

I have a FPGA mounted with pci interface, I'll try to see what happens on
the bus

>Also, I note that when doing simple block reads from pre-
>fetchable PCI space, it appears the 5200 does not prefetch,
>but does each read individually.  This is using stock ELDK
>u-boot and 2.4.24 so I haven't yet determined if it's a
>configuration matter, (or ruled out target disconnects)
>but I'm suspecting that you can't get burst mode from the 
>5200 without using DMA.
Last time I checked, the 2.4 from denx didn't create a pci
window for prefetchable memory so prefetch mem zone
were mapped as non-prefetchable, so no burst for sure.


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