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ARM: add support for generic early_ioremap/early_memremap

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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>
This commit is contained in:
Ard Biesheuvel
2015-09-01 08:59:28 +02:00
committed by ard
parent f7d9248942
commit 2937367b8a
6 changed files with 45 additions and 4 deletions
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29
arch/arm/include/asm/fixmap.h
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@@ -19,20 +19,47 @@ enum fixed_addresses {
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