Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/dma/dummy.c b/kernel/dma/dummy.c
new file mode 100644
index 0000000..0560764
--- /dev/null
+++ b/kernel/dma/dummy.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Dummy DMA ops that always fail.
+ */
+#include <linux/dma-mapping.h>
+
+static int dma_dummy_mmap(struct device *dev, struct vm_area_struct *vma,
+ void *cpu_addr, dma_addr_t dma_addr, size_t size,
+ unsigned long attrs)
+{
+ return -ENXIO;
+}
+
+static dma_addr_t dma_dummy_map_page(struct device *dev, struct page *page,
+ unsigned long offset, size_t size, enum dma_data_direction dir,
+ unsigned long attrs)
+{
+ return DMA_MAPPING_ERROR;
+}
+
+static int dma_dummy_map_sg(struct device *dev, struct scatterlist *sgl,
+ int nelems, enum dma_data_direction dir,
+ unsigned long attrs)
+{
+ return 0;
+}
+
+static int dma_dummy_supported(struct device *hwdev, u64 mask)
+{
+ return 0;
+}
+
+const struct dma_map_ops dma_dummy_ops = {
+ .mmap = dma_dummy_mmap,
+ .map_page = dma_dummy_map_page,
+ .map_sg = dma_dummy_map_sg,
+ .dma_supported = dma_dummy_supported,
+};
+EXPORT_SYMBOL(dma_dummy_ops);