v4.19.13 snapshot.
diff --git a/arch/nios2/mm/dma-mapping.c b/arch/nios2/mm/dma-mapping.c
new file mode 100644
index 0000000..4af9e5b
--- /dev/null
+++ b/arch/nios2/mm/dma-mapping.c
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2009 Wind River Systems Inc
+ * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
+ *
+ * Based on DMA code from MIPS.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/dma-mapping.h>
+#include <linux/io.h>
+#include <linux/cache.h>
+#include <asm/cacheflush.h>
+
+void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr,
+ size_t size, enum dma_data_direction dir)
+{
+ void *vaddr = phys_to_virt(paddr);
+
+ switch (dir) {
+ case DMA_FROM_DEVICE:
+ invalidate_dcache_range((unsigned long)vaddr,
+ (unsigned long)(vaddr + size));
+ break;
+ case DMA_TO_DEVICE:
+ /*
+ * We just need to flush the caches here , but Nios2 flush
+ * instruction will do both writeback and invalidate.
+ */
+ case DMA_BIDIRECTIONAL: /* flush and invalidate */
+ flush_dcache_range((unsigned long)vaddr,
+ (unsigned long)(vaddr + size));
+ break;
+ default:
+ BUG();
+ }
+}
+
+void arch_sync_dma_for_cpu(struct device *dev, phys_addr_t paddr,
+ size_t size, enum dma_data_direction dir)
+{
+ void *vaddr = phys_to_virt(paddr);
+
+ switch (dir) {
+ case DMA_BIDIRECTIONAL:
+ case DMA_FROM_DEVICE:
+ invalidate_dcache_range((unsigned long)vaddr,
+ (unsigned long)(vaddr + size));
+ break;
+ case DMA_TO_DEVICE:
+ break;
+ default:
+ BUG();
+ }
+}
+
+void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
+ gfp_t gfp, unsigned long attrs)
+{
+ void *ret;
+
+ /* optimized page clearing */
+ gfp |= __GFP_ZERO;
+
+ if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
+ gfp |= GFP_DMA;
+
+ ret = (void *) __get_free_pages(gfp, get_order(size));
+ if (ret != NULL) {
+ *dma_handle = virt_to_phys(ret);
+ flush_dcache_range((unsigned long) ret,
+ (unsigned long) ret + size);
+ ret = UNCAC_ADDR(ret);
+ }
+
+ return ret;
+}
+
+void arch_dma_free(struct device *dev, size_t size, void *vaddr,
+ dma_addr_t dma_handle, unsigned long attrs)
+{
+ unsigned long addr = (unsigned long) CAC_ADDR((unsigned long) vaddr);
+
+ free_pages(addr, get_order(size));
+}