arm64: Implement coherent DMA API based on swiotlb

This patch adds support for DMA API cache maintenance on SoCs without
hardware device cache coherency.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index 1ea9f26d1b70..97fcef535a8a 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -166,3 +166,81 @@ ENTRY(__flush_dcache_area)
         dsb     sy
         ret
 ENDPROC(__flush_dcache_area)
+
+/*
+ *      __dma_inv_range(start, end)
+ *      - start   - virtual start address of region
+ *      - end     - virtual end address of region
+ */
+__dma_inv_range:
+        dcache_line_size x2, x3
+        sub     x3, x2, #1
+        bic     x0, x0, x3
+        bic     x1, x1, x3
+1:      dc      ivac, x0                        // invalidate D / U line
+        add     x0, x0, x2
+        cmp     x0, x1
+        b.lo    1b
+        dsb     sy
+        ret
+ENDPROC(__dma_inv_range)
+
+/*
+ *      __dma_clean_range(start, end)
+ *      - start   - virtual start address of region
+ *      - end     - virtual end address of region
+ */
+__dma_clean_range:
+        dcache_line_size x2, x3
+        sub     x3, x2, #1
+        bic     x0, x0, x3
+1:      dc      cvac, x0                        // clean D / U line
+        add     x0, x0, x2
+        cmp     x0, x1
+        b.lo    1b
+        dsb     sy
+        ret
+ENDPROC(__dma_clean_range)
+
+/*
+ *      __dma_flush_range(start, end)
+ *      - start   - virtual start address of region
+ *      - end     - virtual end address of region
+ */
+ENTRY(__dma_flush_range)
+        dcache_line_size x2, x3
+        sub     x3, x2, #1
+        bic     x0, x0, x3
+1:      dc      civac, x0                       // clean & invalidate D / U line
+        add     x0, x0, x2
+        cmp     x0, x1
+        b.lo    1b
+        dsb     sy
+        ret
+ENDPROC(__dma_flush_range)
+
+/*
+ *      __dma_map_area(start, size, dir)
+ *      - start - kernel virtual start address
+ *      - size  - size of region
+ *      - dir   - DMA direction
+ */
+ENTRY(__dma_map_area)
+        add     x1, x1, x0
+        cmp     w2, #DMA_FROM_DEVICE
+        b.eq    __dma_inv_range
+        b       __dma_clean_range
+ENDPROC(__dma_map_area)
+
+/*
+ *      __dma_unmap_area(start, size, dir)
+ *      - start - kernel virtual start address
+ *      - size  - size of region
+ *      - dir   - DMA direction
+ */
+ENTRY(__dma_unmap_area)
+        add     x1, x1, x0
+        cmp     w2, #DMA_TO_DEVICE
+        b.ne    __dma_inv_range
+        ret
+ENDPROC(__dma_unmap_area)