1 files changed, 117 insertions, 0 deletions

diff --git a/kernel/arch/mips/bmips/dma.c b/kernel/arch/mips/bmips/dma.c
new file mode 100644
index 000000000..04790f4e1
--- /dev/null
+++ b/kernel/arch/mips/bmips/dma.c
@@ -0,0 +1,117 @@
+/*
+ * 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.
+ *
+ * Copyright (C) 2014 Kevin Cernekee <cernekee@gmail.com>
+ */
+
+#define pr_fmt(fmt)		"bmips-dma: " fmt
+
+#include <linux/device.h>
+#include <linux/dma-direction.h>
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <dma-coherence.h>
+
+/*
+ * BCM338x has configurable address translation windows which allow the
+ * peripherals' DMA addresses to be different from the Zephyr-visible
+ * physical addresses.  e.g. usb_dma_addr = zephyr_pa ^ 0x08000000
+ *
+ * If the "brcm,ubus" node has a "dma-ranges" property we will enable this
+ * translation globally using the provided information.  This implements a
+ * very limited subset of "dma-ranges" support and it will probably be
+ * replaced by a more generic version later.
+ */
+
+struct bmips_dma_range {
+	u32			child_addr;
+	u32			parent_addr;
+	u32			size;
+};
+
+static struct bmips_dma_range *bmips_dma_ranges;
+
+#define FLUSH_RAC		0x100
+
+static dma_addr_t bmips_phys_to_dma(struct device *dev, phys_addr_t pa)
+{
+	struct bmips_dma_range *r;
+
+	for (r = bmips_dma_ranges; r && r->size; r++) {
+		if (pa >= r->child_addr &&
+		    pa < (r->child_addr + r->size))
+			return pa - r->child_addr + r->parent_addr;
+	}
+	return pa;
+}
+
+dma_addr_t plat_map_dma_mem(struct device *dev, void *addr, size_t size)
+{
+	return bmips_phys_to_dma(dev, virt_to_phys(addr));
+}
+
+dma_addr_t plat_map_dma_mem_page(struct device *dev, struct page *page)
+{
+	return bmips_phys_to_dma(dev, page_to_phys(page));
+}
+
+unsigned long plat_dma_addr_to_phys(struct device *dev, dma_addr_t dma_addr)
+{
+	struct bmips_dma_range *r;
+
+	for (r = bmips_dma_ranges; r && r->size; r++) {
+		if (dma_addr >= r->parent_addr &&
+		    dma_addr < (r->parent_addr + r->size))
+			return dma_addr - r->parent_addr + r->child_addr;
+	}
+	return dma_addr;
+}
+
+static int __init bmips_init_dma_ranges(void)
+{
+	struct device_node *np =
+		of_find_compatible_node(NULL, NULL, "brcm,ubus");
+	const __be32 *data;
+	struct bmips_dma_range *r;
+	int len;
+
+	if (!np)
+		return 0;
+
+	data = of_get_property(np, "dma-ranges", &len);
+	if (!data)
+		goto out_good;
+
+	len /= sizeof(*data) * 3;
+	if (!len)
+		goto out_bad;
+
+	/* add a dummy (zero) entry at the end as a sentinel */
+	bmips_dma_ranges = kzalloc(sizeof(struct bmips_dma_range) * (len + 1),
+				   GFP_KERNEL);
+	if (!bmips_dma_ranges)
+		goto out_bad;
+
+	for (r = bmips_dma_ranges; len; len--, r++) {
+		r->child_addr = be32_to_cpup(data++);
+		r->parent_addr = be32_to_cpup(data++);
+		r->size = be32_to_cpup(data++);
+	}
+
+out_good:
+	of_node_put(np);
+	return 0;
+
+out_bad:
+	pr_err("error parsing dma-ranges property\n");
+	of_node_put(np);
+	return -EINVAL;
+}
+arch_initcall(bmips_init_dma_ranges);