[PATCH 13/15] ARM: make mach/io.h include optional

On Tuesday 14 February 2012, Russell King - ARM Linux wrote:

quoted

orion5x maps 2 1MB regions for PCI and PCIE. How would you support 2 io
ranges?

That's not the only platform which effectively has two IO ranges.  The
PCMCIA sockets on SA11x0 and probably PXA both have their own separate
IO region.  Arnd's idea for this was to map 32k from one and 32k from
the other into a single 64k space, and adapt soc_common to cope.

When going through the list today, I found that mv78xx0 in fact has eight
PCIe root complexes with their own I/O spaces.
This could still work with the method I suggested but it would limit
the I/O space per bus to 8kb, which is fairly small, so I'd still consider
using a 1MB space (allowing 16 separte 64 I/O windows) an equally
reasonable option.

quoted

BTW, I noticed some static mappings at 0xffxxxxxx. Are those even a
valid address?

Nothing invalid about them as such, but I have tried to discourage their
use in case we decide that we want to go for a default 14MB DMA region.

We still have the option to either put the I/O spaces in the vmalloc area
where they typically are now, or (provided it's small enough) put them
into the fixmap area, which is a little under 1MB in total size and
almost entirely unused on ARM today.

	Arnd