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>
diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
index 58cfe9f..5c17d2d 100644
--- a/arch/arm/include/asm/fixmap.h
+++ b/arch/arm/include/asm/fixmap.h
@@ -19,20 +19,47 @@
FIX_TEXT_POKE0,
FIX_TEXT_POKE1,
- __end_of_fixed_addresses
+ __end_of_fixmap_region,
+
+ /*
+ * Share the kmap() region with early_ioremap(): this is guaranteed
+ * not to clash since early_ioremap() is only available before
+ * paging_init(), and kmap() only after.
+ */
+#define NR_FIX_BTMAPS 32
+#define FIX_BTMAPS_SLOTS 7
+#define TOTAL_FIX_BTMAPS (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
+
+ FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
+ FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
+ __end_of_early_ioremap_region
};
+static const enum fixed_addresses __end_of_fixed_addresses =
+ __end_of_fixmap_region > __end_of_early_ioremap_region ?
+ __end_of_fixmap_region : __end_of_early_ioremap_region;
+
#define FIXMAP_PAGE_COMMON (L_PTE_YOUNG | L_PTE_PRESENT | L_PTE_XN | L_PTE_DIRTY)
#define FIXMAP_PAGE_NORMAL (FIXMAP_PAGE_COMMON | L_PTE_MT_WRITEBACK)
+#define FIXMAP_PAGE_RO (FIXMAP_PAGE_NORMAL | L_PTE_RDONLY)
/* Used by set_fixmap_(io|nocache), both meant for mapping a device */
#define FIXMAP_PAGE_IO (FIXMAP_PAGE_COMMON | L_PTE_MT_DEV_SHARED | L_PTE_SHARED)
#define FIXMAP_PAGE_NOCACHE FIXMAP_PAGE_IO
+#define __early_set_fixmap __set_fixmap
+
+#ifdef CONFIG_MMU
+
void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
void __init early_fixmap_init(void);
#include <asm-generic/fixmap.h>
+#else
+
+static inline void early_fixmap_init(void) { }
+
+#endif
#endif