[ARM] introduce dma_cache_maint_page()

This is a helper to be used by the DMA mapping API to handle cache
maintenance for memory identified by a page structure instead of a
virtual address.  Those pages may or may not be highmem pages, and
when they're highmem pages, they may or may not be virtually mapped.
When they're not mapped then there is no L1 cache to worry about. But
even in that case the L2 cache must be processed since unmapped highmem
pages can still be L2 cached.

Signed-off-by: Nicolas Pitre <nico@marvell.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/arm/include/asm/highmem.h b/arch/arm/include/asm/highmem.h
index 023d5b374544..7f36d00600b4 100644
--- a/arch/arm/include/asm/highmem.h
+++ b/arch/arm/include/asm/highmem.h
@@ -15,7 +15,10 @@
 
 extern pte_t *pkmap_page_table;
 
+#define ARCH_NEEDS_KMAP_HIGH_GET
+
 extern void *kmap_high(struct page *page);
+extern void *kmap_high_get(struct page *page);
 extern void kunmap_high(struct page *page);
 
 extern void *kmap(struct page *page);