diff options
Diffstat (limited to 'arch/arm/mm/dma-mapping.c')
| -rw-r--r-- | arch/arm/mm/dma-mapping.c | 33 |
1 files changed, 23 insertions, 10 deletions
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 13fa536d82e..c704eed63c5 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -24,15 +24,6 @@ #include <asm/tlbflush.h> #include <asm/sizes.h> -/* Sanity check size */ -#if (CONSISTENT_DMA_SIZE % SZ_2M) -#error "CONSISTENT_DMA_SIZE must be multiple of 2MiB" -#endif - -#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT) -#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PGDIR_SHIFT) -#define NUM_CONSISTENT_PTES (CONSISTENT_DMA_SIZE >> PGDIR_SHIFT) - static u64 get_coherent_dma_mask(struct device *dev) { u64 mask = ISA_DMA_THRESHOLD; @@ -123,6 +114,15 @@ static void __dma_free_buffer(struct page *page, size_t size) } #ifdef CONFIG_MMU +/* Sanity check size */ +#if (CONSISTENT_DMA_SIZE % SZ_2M) +#error "CONSISTENT_DMA_SIZE must be multiple of 2MiB" +#endif + +#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT) +#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PGDIR_SHIFT) +#define NUM_CONSISTENT_PTES (CONSISTENT_DMA_SIZE >> PGDIR_SHIFT) + /* * These are the page tables (2MB each) covering uncached, DMA consistent allocations */ @@ -183,6 +183,8 @@ static void * __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot) { struct arm_vmregion *c; + size_t align; + int bit; if (!consistent_pte[0]) { printk(KERN_ERR "%s: not initialised\n", __func__); @@ -191,9 +193,20 @@ __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot) } /* + * Align the virtual region allocation - maximum alignment is + * a section size, minimum is a page size. This helps reduce + * fragmentation of the DMA space, and also prevents allocations + * smaller than a section from crossing a section boundary. + */ + bit = fls(size - 1) + 1; + if (bit > SECTION_SHIFT) + bit = SECTION_SHIFT; + align = 1 << bit; + + /* * Allocate a virtual address in the consistent mapping region. */ - c = arm_vmregion_alloc(&consistent_head, size, + c = arm_vmregion_alloc(&consistent_head, align, size, gfp & ~(__GFP_DMA | __GFP_HIGHMEM)); if (c) { pte_t *pte; |