1 files changed, 82 insertions, 0 deletions
diff --git a/arch/nds32/kernel/dma.c b/arch/nds32/kernel/dma.c
new file mode 100644
index 000000000..2ac8e6c82
--- /dev/null
+++ b/arch/nds32/kernel/dma.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/dma-map-ops.h>
+#include <linux/cache.h>
+#include <linux/highmem.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <asm/proc-fns.h>
+
+static inline void cache_op(phys_addr_t paddr, size_t size,
+		void (*fn)(unsigned long start, unsigned long end))
+{
+	struct page *page = pfn_to_page(paddr >> PAGE_SHIFT);
+	unsigned offset = paddr & ~PAGE_MASK;
+	size_t left = size;
+	unsigned long start;
+
+	do {
+		size_t len = left;
+
+		if (PageHighMem(page)) {
+			void *addr;
+
+			if (offset + len > PAGE_SIZE) {
+				if (offset >= PAGE_SIZE) {
+					page += offset >> PAGE_SHIFT;
+					offset &= ~PAGE_MASK;
+				}
+				len = PAGE_SIZE - offset;
+			}
+
+			addr = kmap_atomic(page);
+			start = (unsigned long)(addr + offset);
+			fn(start, start + len);
+			kunmap_atomic(addr);
+		} else {
+			start = (unsigned long)phys_to_virt(paddr);
+			fn(start, start + size);
+		}
+		offset = 0;
+		page++;
+		left -= len;
+	} while (left);
+}
+
+void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
+		enum dma_data_direction dir)
+{
+	switch (dir) {
+	case DMA_FROM_DEVICE:
+		break;
+	case DMA_TO_DEVICE:
+	case DMA_BIDIRECTIONAL:
+		cache_op(paddr, size, cpu_dma_wb_range);
+		break;
+	default:
+		BUG();
+	}
+}
+
+void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
+		enum dma_data_direction dir)
+{
+	switch (dir) {
+	case DMA_TO_DEVICE:
+		break;
+	case DMA_FROM_DEVICE:
+	case DMA_BIDIRECTIONAL:
+		cache_op(paddr, size, cpu_dma_inval_range);
+		break;
+	default:
+		BUG();
+	}
+}
+
+void arch_dma_prep_coherent(struct page *page, size_t size)
+{
+	cache_op(page_to_phys(page), size, cpu_dma_wbinval_range);
+}