1 files changed, 81 insertions, 0 deletions

diff --git a/arch/mips/bcm3384/dma.c b/arch/mips/bcm3384/dma.c
new file mode 100644
index 000000000000..ea42012fd4f5
--- /dev/null
+++ b/arch/mips/bcm3384/dma.c
@@ -0,0 +1,81 @@
+/*
+ * 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>
+ */
+
+#include <linux/device.h>
+#include <linux/dma-direction.h>
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/of.h>
+#include <linux/pci.h>
+#include <linux/types.h>
+#include <dma-coherence.h>
+
+/*
+ * BCM3384 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 our DT "memory" node has a "dma-xor-mask" property we will enable this
+ * translation using the provided offset.
+ */
+static u32 bcm3384_dma_xor_mask;
+static u32 bcm3384_dma_xor_limit = 0xffffffff;
+
+/*
+ * PCI collapses the memory hole at 0x10000000 - 0x1fffffff.
+ * On systems with a dma-xor-mask, this range is guaranteed to live above
+ * the dma-xor-limit.
+ */
+#define BCM3384_MEM_HOLE_PA     0x10000000
+#define BCM3384_MEM_HOLE_SIZE   0x10000000
+
+static dma_addr_t bcm3384_phys_to_dma(struct device *dev, phys_addr_t pa)
+{
+        if (dev && dev_is_pci(dev) &&
+            pa >= (BCM3384_MEM_HOLE_PA + BCM3384_MEM_HOLE_SIZE))
+                return pa - BCM3384_MEM_HOLE_SIZE;
+        if (pa <= bcm3384_dma_xor_limit)
+                return pa ^ bcm3384_dma_xor_mask;
+        return pa;
+}
+
+dma_addr_t plat_map_dma_mem(struct device *dev, void *addr, size_t size)
+{
+        return bcm3384_phys_to_dma(dev, virt_to_phys(addr));
+}
+
+dma_addr_t plat_map_dma_mem_page(struct device *dev, struct page *page)
+{
+        return bcm3384_phys_to_dma(dev, page_to_phys(page));
+}
+
+unsigned long plat_dma_addr_to_phys(struct device *dev, dma_addr_t dma_addr)
+{
+        if (dev && dev_is_pci(dev) &&
+            dma_addr >= BCM3384_MEM_HOLE_PA)
+                return dma_addr + BCM3384_MEM_HOLE_SIZE;
+        if ((dma_addr ^ bcm3384_dma_xor_mask) <= bcm3384_dma_xor_limit)
+                return dma_addr ^ bcm3384_dma_xor_mask;
+        return dma_addr;
+}
+
+static int __init bcm3384_init_dma_xor(void)
+{
+        struct device_node *np = of_find_node_by_type(NULL, "memory");
+
+        if (!np)
+                return 0;
+
+        of_property_read_u32(np, "dma-xor-mask", &bcm3384_dma_xor_mask);
+        of_property_read_u32(np, "dma-xor-limit", &bcm3384_dma_xor_limit);
+
+        of_node_put(np);
+        return 0;
+}
+arch_initcall(bcm3384_init_dma_xor);