Resguardo inicial

linux-7.2.3/arch/loongarch/kernel/dma.c

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#include <linux/acpi.h>
+#include <linux/dma-direct.h>
+
+void acpi_arch_dma_setup(struct device *dev)
+{
+	int ret;
+	u64 mask, end;
+	const struct bus_dma_region *map = NULL;
+
+	ret = acpi_dma_get_range(dev, &map);
+	if (!ret && map) {
+		end = dma_range_map_max(map);
+
+		mask = DMA_BIT_MASK(ilog2(end) + 1);
+		dev->bus_dma_limit = end;
+		dev->dma_range_map = map;
+		dev->coherent_dma_mask = min(dev->coherent_dma_mask, mask);
+		*dev->dma_mask = min(*dev->dma_mask, mask);
+	}
+
+}