summaryrefslogtreecommitdiffstats
path: root/arch/arm/mm/dma-mapping.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/mm/dma-mapping.c')
-rw-r--r--arch/arm/mm/dma-mapping.c72
1 files changed, 71 insertions, 1 deletions
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index f1ef5613ccd4..510c179b0ac8 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -19,6 +19,7 @@
#include <linux/dma-mapping.h>
#include <asm/memory.h>
+#include <asm/highmem.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/sizes.h>
@@ -517,6 +518,74 @@ void dma_cache_maint(const void *start, size_t size, int direction)
}
EXPORT_SYMBOL(dma_cache_maint);
+static void dma_cache_maint_contiguous(struct page *page, unsigned long offset,
+ size_t size, int direction)
+{
+ void *vaddr;
+ unsigned long paddr;
+ void (*inner_op)(const void *, const void *);
+ void (*outer_op)(unsigned long, unsigned long);
+
+ switch (direction) {
+ case DMA_FROM_DEVICE: /* invalidate only */
+ inner_op = dmac_inv_range;
+ outer_op = outer_inv_range;
+ break;
+ case DMA_TO_DEVICE: /* writeback only */
+ inner_op = dmac_clean_range;
+ outer_op = outer_clean_range;
+ break;
+ case DMA_BIDIRECTIONAL: /* writeback and invalidate */
+ inner_op = dmac_flush_range;
+ outer_op = outer_flush_range;
+ break;
+ default:
+ BUG();
+ }
+
+ if (!PageHighMem(page)) {
+ vaddr = page_address(page) + offset;
+ inner_op(vaddr, vaddr + size);
+ } else {
+ vaddr = kmap_high_get(page);
+ if (vaddr) {
+ vaddr += offset;
+ inner_op(vaddr, vaddr + size);
+ kunmap_high(page);
+ }
+ }
+
+ paddr = page_to_phys(page) + offset;
+ outer_op(paddr, paddr + size);
+}
+
+void dma_cache_maint_page(struct page *page, unsigned long offset,
+ size_t size, int dir)
+{
+ /*
+ * A single sg entry may refer to multiple physically contiguous
+ * pages. But we still need to process highmem pages individually.
+ * If highmem is not configured then the bulk of this loop gets
+ * optimized out.
+ */
+ size_t left = size;
+ do {
+ size_t len = left;
+ if (PageHighMem(page) && len + offset > PAGE_SIZE) {
+ if (offset >= PAGE_SIZE) {
+ page += offset / PAGE_SIZE;
+ offset %= PAGE_SIZE;
+ }
+ len = PAGE_SIZE - offset;
+ }
+ dma_cache_maint_contiguous(page, offset, len, dir);
+ offset = 0;
+ page++;
+ left -= len;
+ } while (left);
+}
+EXPORT_SYMBOL(dma_cache_maint_page);
+
/**
* dma_map_sg - map a set of SG buffers for streaming mode DMA
* @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
@@ -614,7 +683,8 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
continue;
if (!arch_is_coherent())
- dma_cache_maint(sg_virt(s), s->length, dir);
+ dma_cache_maint_page(sg_page(s), s->offset,
+ s->length, dir);
}
}
EXPORT_SYMBOL(dma_sync_sg_for_device);
OpenPOWER on IntegriCloud