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-rw-r--r--kernel/arch/mips/bmips/dma.c117
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);