omap: iommu: program constraints based on platform data

IOMMU driver requests and releases constraints in iommu_get
and iommu_put respectively. These constraints are actually
needed only on OMAP4 and beyond for sub-systems that have
an AMMU. The current driver code has these values hard-coded
for all the chips.

A new platform data field has been added now for the constraints
values, and this allows the values to be programmed based on
the OMAP chip and also allow a unique value if needed for each
iommu instance.

The logic in IOMMU driver code is adjusted to request the
constraints only if the relevant platform data field is set.

Change-Id: Iab18cbdde1d7fa7507dbff0b9512c8577b42fefd
Signed-off-by: Subramaniam C.A <subramaniam.ca@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
omap: iommu: relax constraint value to allow CSWR

The iommu driver currently requests a latency constraint,
if configured in platform data, on the power domain it is
present in. These values are required only for OMAP4 and
beyond and is done to ensure the AMMU context is maintained
when the corresponding power domain goes to a low power state
during cpuidle path. The AMMU context is retained in CSWR, but
is lost in OSWR.

The current constraint value (10) for OMAP4+ is high and
restricts the power domain to remain in ON state as long as
the processor is active. This value is relaxed to 400 to
allow a lower power CSWR state during cpuidle path.

The context is saved and restored properly when suspending
the remote processor.

Change-Id: I89fd125f2244ae1691843c3c078aa6314a7ae8a6
Signed-off-by: Miguel Vadillo <vadillo@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>
ARM: Add init_consistent_dma_size()

This function can be called during boot to increase the size of the consistent
DMA region above it's default value of 2MB. It must be called before the memory
allocator is initialised, i.e. before any core_initcall.

Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>

Conflicts:
	arch/arm/include/asm/dma-mapping.h
ARM: Remove support for macro CONSISTENT_DMA_SIZE

There are now no platforms which set this macro.

Signed-off-by: Jon Medhurst <tixy@yxit.co.uk>
arm: Increase the DMA consistent memory zone to 4MB

Increase the zone for mapping DMA memory on most platforms from 2MB
to 4 MB. The actual memory comes from the normal pool, this
change just increases the virtual range where the memory can be mappped
(at the cost of 1 more 2MB pagetable).