arc: remove the partial DMA_ATTR_NON_CONSISTENT support

The arc DMA code supports DMA_ATTR_NON_CONSISTENT allocations, but does
not provide a cache_sync operation.  This means any user of it will
never be able to actually transfer cache ownership and thus cause
coherency bugs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Evgeniy Paltsev <paltsev@synopsys.com>
Tested-by: Evgeniy Paltsev <paltsev@synopsys.com>

diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 1525ac0..9832928 100644 (file)
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -24,7 +24,6 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
        struct page *page;
        phys_addr_t paddr;
        void *kvaddr;
-       bool need_coh = !(attrs & DMA_ATTR_NON_CONSISTENT);
 
        /*
         * __GFP_HIGHMEM flag is cleared by upper layer functions
@@ -46,14 +45,10 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
         * A coherent buffer needs MMU mapping to enforce non-cachability.
         * kvaddr is kernel Virtual address (0x7000_0000 based).
         */
-       if (need_coh) {
-               kvaddr = ioremap_nocache(paddr, size);
-               if (kvaddr == NULL) {
-                       __free_pages(page, order);
-                       return NULL;
-               }
-       } else {
-               kvaddr = (void *)(u32)paddr;
+       kvaddr = ioremap_nocache(paddr, size);
+       if (kvaddr == NULL) {
+               __free_pages(page, order);
+               return NULL;
        }
 
        /*
@@ -66,9 +61,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
         * Currently flush_cache_vmap nukes the L1 cache completely which
         * will be optimized as a separate commit
         */
-       if (need_coh)
-               dma_cache_wback_inv(paddr, size);
-
+       dma_cache_wback_inv(paddr, size);
        return kvaddr;
 }
 
@@ -78,9 +71,7 @@ void arch_dma_free(struct device *dev, size_t size, void *vaddr,
        phys_addr_t paddr = dma_handle;
        struct page *page = virt_to_page(paddr);
 
-       if (!(attrs & DMA_ATTR_NON_CONSISTENT))
-               iounmap((void __force __iomem *)vaddr);
-
+       iounmap((void __force __iomem *)vaddr);
        __free_pages(page, get_order(size));
 }