xtensa: make dma_cache_sync a no-op

xtensa does not implement DMA_ATTR_NON_CONSISTENT allocations, so it
doesn't make any sense to do any work in dma_cache_sync given that it
must be a no-op when dma_alloc_attrs returns coherent memory.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>

2 files changed, 4 insertions, 25 deletions

diff --git a/arch/xtensa/include/asm/dma-mapping.h b/arch/xtensa/include/asm/dma-mapping.h
index 269738dc9d1d..353e0314d6ba 100644
--- a/arch/xtensa/include/asm/dma-mapping.h
+++ b/arch/xtensa/include/asm/dma-mapping.h
@@ -23,8 +23,10 @@ static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
         return &xtensa_dma_map_ops;
 }
 
-void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
-                    enum dma_data_direction direction);
+static inline void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
+                    enum dma_data_direction direction)
+{
+}
 
 static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
 {
diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c
index cec86a1c2acc..623720a11143 100644
--- a/arch/xtensa/kernel/pci-dma.c
+++ b/arch/xtensa/kernel/pci-dma.c
@@ -26,29 +26,6 @@
 #include <asm/cacheflush.h>
 #include <asm/io.h>
 
-void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
-                    enum dma_data_direction dir)
-{
-        switch (dir) {
-        case DMA_BIDIRECTIONAL:
-                __flush_invalidate_dcache_range((unsigned long)vaddr, size);
-                break;
-
-        case DMA_FROM_DEVICE:
-                __invalidate_dcache_range((unsigned long)vaddr, size);
-                break;
-
-        case DMA_TO_DEVICE:
-                __flush_dcache_range((unsigned long)vaddr, size);
-                break;
-
-        case DMA_NONE:
-                BUG();
-                break;
-        }
-}
-EXPORT_SYMBOL(dma_cache_sync);
-
 static void do_cache_op(dma_addr_t dma_handle, size_t size,
                         void (*fn)(unsigned long, unsigned long))
 {