On 24.1.2012 6:00, Ján Veselý wrote:
>>  - making USB work on ppc32, WIP, almost there
> 
> ppc32 PCI driver is available in my usb branch, it's a slightly
> modified intelpci driver (endianess, port locations), I'll add the
> OHCI bits later.

Is the PCI bridge just similar or is it essentially the same thing? If
it is physically the same or compatible thing, we should probably
consider options for using the same driver for it.

You mention the difference in register layout. This could be either
because the device is indeed incompatible or because of some platform
specifics.

For example, on ia64, there is a legacy I/O space, which replaces the
ia32/amd64oe IO port space. It ds so by mapping groups of four
consecutive I/O ports to a page in the legacy I/O space. Consecutive
groups of ports will lie in consecutive pages. The original ia32 I/O
port space is thus inflated from 64KiB to 64MiB.

If one sees the legacy I/O space as ordinary memory mapped registers, it
may happen that some registers that are adjacent in the ia32 I/O port
space will not be adjacent in the ia64 legacy I/O space.

The problem goes away if you continue to look at the registers in the
legacy I/O space as if they were still special, much like the original
ia32 I/O ports. You can then map port numbers to respective memory
mapped registers and vice versa and, theoretically, use unmodified
driver for both.

Just being curious :-)

Jakub

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