[PATCH] arch/arm: mmu: add map_io_range()

[Robert Jarzmik]

Add a function to remap an IO range into a virtual addresses
range. This is particulary usefull for the few devices
mapped at physical address 0, as the MTD boot devices.

Signed-off-by: Robert Jarzmik <robert.jarzmik at free.fr>
---
 arch/arm/cpu/mmu.c         |   12 ++++++++++++
 arch/arm/include/asm/mmu.h |    6 ++++++
 2 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/arch/arm/cpu/mmu.c b/arch/arm/cpu/mmu.c
index 8e4e81a..c6c91df 100644
--- a/arch/arm/cpu/mmu.c
+++ b/arch/arm/cpu/mmu.c
@@ -111,6 +111,18 @@ static void remap_range(void *_start, size_t size, uint32_t flags)
 	tlb_invalidate();
 }
 
+void *map_io_sections(unsigned long phys, void *_start, size_t size)
+{
+	unsigned long start = (unsigned long)_start, sec;
+
+	phys >>= 20;
+	for (sec = start; sec < start + size; sec += (1 << 20))
+		ttb[sec >> 20] = (phys++ << 20) | PMD_SECT_DEF_UNCACHED;
+
+	tlb_invalidate();
+	return _start;
+}
+
 /*
  * remap the memory bank described by mem cachable and
  * bufferable
diff --git a/arch/arm/include/asm/mmu.h b/arch/arm/include/asm/mmu.h
index 9ca5e2a..f5ae7a8 100644
--- a/arch/arm/include/asm/mmu.h
+++ b/arch/arm/include/asm/mmu.h
@@ -32,6 +32,7 @@ void dma_flush_range(unsigned long, unsigned long);
 void dma_inv_range(unsigned long, unsigned long);
 unsigned long virt_to_phys(void *virt);
 void *phys_to_virt(unsigned long phys);
+void *map_io_sections(unsigned long physaddr, void *start, size_t size);
 
 #else
 static inline void *dma_alloc_coherent(size_t size)
@@ -66,6 +67,11 @@ static inline void dma_inv_range(unsigned long s, unsigned long e)
 {
 }
 
+static inline void *map_io_sections(unsigned long phys, void *start, size_t size)
+{
+	return (void *)phys;
+}
+
 #endif
 
 #ifdef CONFIG_CACHE_L2X0
-- 
1.7.5.4