ARM: Add fixed PCI i/o mapping

This adds a fixed virtual mapping for PCI i/o addresses. The mapping is
located at the last 2MB of vmalloc region (0xfee00000-0xff000000). 2MB
is used to align with PMD size, but IO_SPACE_LIMIT is 1MB. The space
is reserved after .map_io and can be mapped at any time later with
pci_ioremap_io. Platforms which need early i/o mapping (e.g. for vga
console) can call pci_map_io_early in their .map_io function.

This has changed completely from the 1st implementation which only
supported creating the static mapping at .map_io.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Nicolas Pitre <nico@linaro.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/Documentation/arm/memory.txt b/Documentation/arm/memory.txt
index 208a2d465b92..4bfb9ffbdbc1 100644
--- a/Documentation/arm/memory.txt
+++ b/Documentation/arm/memory.txt
@@ -51,6 +51,9 @@ ffc00000	ffefffff	DMA memory mapping region.  Memory returned
 ff000000        ffbfffff        Reserved for future expansion of DMA
                                 mapping region.
 
+fee00000        feffffff        Mapping of PCI I/O space. This is a static
+                                mapping within the vmalloc space.
+
 VMALLOC_START   VMALLOC_END-1   vmalloc() / ioremap() space.
                                 Memory returned by vmalloc/ioremap will
                                 be dynamically placed in this region.