ARM: add support for generic early_ioremap/early_memremap

This enables the generic early_ioremap implementation for ARM.

It uses the fixmap region reserved for kmap. Since early_ioremap
is only supported before paging_init(), and kmap is only supported
afterwards, this is guaranteed not to cause any clashes.

Tested-by: Ryan Harkin <ryan.harkin@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

2 files changed, 10 insertions, 1 deletions

diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index 0c81056c1dd7..66a978d05958 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -30,6 +30,7 @@
 #include <asm/cp15.h>
 #include <asm/cputype.h>
 #include <asm/cacheflush.h>
+#include <asm/early_ioremap.h>
 #include <asm/mmu_context.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
@@ -469,3 +470,11 @@ int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr)
 }
 EXPORT_SYMBOL_GPL(pci_ioremap_io);
 #endif
+
+/*
+ * Must be called after early_fixmap_init
+ */
+void __init early_ioremap_init(void)
+{
+        early_ioremap_setup();
+}
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 4867f5daf82c..de19f90221e2 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -390,7 +390,7 @@ void __init early_fixmap_init(void)
          * The early fixmap range spans multiple pmds, for which
          * we are not prepared:
          */
-        BUILD_BUG_ON((__fix_to_virt(__end_of_permanent_fixed_addresses) >> PMD_SHIFT)
+        BUILD_BUG_ON((__fix_to_virt(__end_of_early_ioremap_region) >> PMD_SHIFT)
                      != FIXADDR_TOP >> PMD_SHIFT);
 
         pmd = fixmap_pmd(FIXADDR_TOP);