Am 01.10.2010 um 00:25 schrieb Alexander Graf:
On 01.10.2010, at 00:09, Benjamin Herrenschmidt wrote:
On Fri, 2010-10-01 at 00:03 +0200, Alexander Graf wrote:
If I understand the U3 and U4 designs correctly, PCI is always bound to be within the first 32 bits. Copying Ben for verification. I don't really remember having seen 64 bit cells on any Power system either, but I could be wrong. Again, let's ask the expert here :).
Yes. However, on js2x, the firmware plays funny remapping tricks...
In general, however, OpenBIOS should be fixed. It's getting more common to have even 32-bit machines with physical devices above 32-bit (even ARM is now growing an equivalent of PAE for that, and almost all 4xx powerpc do that).
So how does the firmware tell the OS that a device is on a 64 bit physical address if it only knows about 32 bit wide cells?
By concatenating two 32 bit wide cells in Big Endian order, it seems. :)
Andreas