ARM: add generic ioremap optimization by reusing static mappings

Now that we have all the static mappings from iotable_init() located
in the vmalloc area, it is trivial to optimize ioremap by reusing those
static mappings when the requested physical area fits in one of them,
and so in a generic way for all platforms.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Kevin Hilman <khilman@ti.com>
Tested-by: Jamie Iles <jamie@jamieiles.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index ad7cce3bc431..70f6d3ea4834 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -21,6 +21,20 @@ const struct mem_type *get_mem_type(unsigned int type);
 
 extern void __flush_dcache_page(struct address_space *mapping, struct page *page);
 
+/*
+ * ARM specific vm_struct->flags bits.
+ */
+
+/* (super)section-mapped I/O regions used by ioremap()/iounmap() */
+#define VM_ARM_SECTION_MAPPING  0x80000000
+
+/* permanent static mappings from iotable_init() */
+#define VM_ARM_STATIC_MAPPING   0x40000000
+
+/* mapping type (attributes) for permanent static mappings */
+#define VM_ARM_MTYPE(mt)                ((mt) << 20)
+#define VM_ARM_MTYPE_MASK       (0x1f << 20)
+
 #endif
 
 #ifdef CONFIG_ZONE_DMA