[PATCHv2 2/4] ARM: mm: allow sub-architectures to override PCI I/O memory type

On Tue, May 13, 2014 at 11:10:37AM +0100, Thomas Petazzoni wrote:

Due to a design incompatibility between the PCIe Marvell controller
and the Cortex-A9, stressing PCIe devices with a lot of traffic
quickly causes a deadlock.

One part of the workaround for this is to have all PCIe regions mapped
as MT_MEMORY_SO instead of MT_DEVICE. While the arch_ioremap_caller()
mechanism allows sub-architecture code to override ioremap(), used to
map PCIe memory regions, there isn't such a mechanism to override the
behavior of pci_ioremap_io().

This commit adds the arch_pci_ioremap_mem_type variable, initialized
to MT_DEVICE by default, and that sub-architecture code can
override. We have chosen to expose a single variable rather than
offering the possibility of overriding the entire pci_ioremap_io(),
because implementing pci_ioremap_io() requires calling functions
(get_mem_type()) that are private to the arch/arm/mm/ code.

Signed-off-by: Thomas Petazzoni <redacted>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>