1 files changed, 25 insertions, 0 deletions
diff --git a/arch/mips/loongson64/dma.c b/arch/mips/loongson64/dma.c
new file mode 100644
index 000000000000..5e86635f71db
--- /dev/null
+++ b/arch/mips/loongson64/dma.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/dma-direct.h>
+#include <linux/init.h>
+#include <linux/swiotlb.h>
+
+dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
+{
+	/* We extract 2bit node id (bit 44~47, only bit 44~45 used now) from
+	 * Loongson-3's 48bit address space and embed it into 40bit */
+	long nid = (paddr >> 44) & 0x3;
+	return ((nid << 44) ^ paddr) | (nid << 37);
+}
+
+phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
+{
+	/* We extract 2bit node id (bit 44~47, only bit 44~45 used now) from
+	 * Loongson-3's 48bit address space and embed it into 40bit */
+	long nid = (daddr >> 37) & 0x3;
+	return ((nid << 37) ^ daddr) | (nid << 44);
+}
+
+void __init plat_swiotlb_setup(void)
+{
+	swiotlb_init(1);
+}