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-rw-r--r--arch/powerpc/kernel/dma.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
new file mode 100644
index 00000000000..1562daf8839
--- /dev/null
+++ b/arch/powerpc/kernel/dma.c
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
+ *
+ * Provide default implementations of the DMA mapping callbacks for
+ * directly mapped busses.
+ */
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <asm/bug.h>
+#include <asm/abs_addr.h>
+
+/*
+ * Generic direct DMA implementation
+ *
+ * This implementation supports a per-device offset that can be applied if
+ * the address at which memory is visible to devices is not 0. Platform code
+ * can set archdata.dma_data to an unsigned long holding the offset. By
+ * default the offset is PCI_DRAM_OFFSET.
+ */
+
+static unsigned long get_dma_direct_offset(struct device *dev)
+{
+ if (dev)
+ return (unsigned long)dev->archdata.dma_data;
+
+ return PCI_DRAM_OFFSET;
+}
+
+void *dma_direct_alloc_coherent(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t flag)
+{
+ void *ret;
+#ifdef CONFIG_NOT_COHERENT_CACHE
+ ret = __dma_alloc_coherent(size, dma_handle, flag);
+ if (ret == NULL)
+ return NULL;
+ *dma_handle += get_dma_direct_offset(dev);
+ return ret;
+#else
+ struct page *page;
+ int node = dev_to_node(dev);
+
+ /* ignore region specifiers */
+ flag &= ~(__GFP_HIGHMEM);
+
+ page = alloc_pages_node(node, flag, get_order(size));
+ if (page == NULL)
+ return NULL;
+ ret = page_address(page);
+ memset(ret, 0, size);
+ *dma_handle = virt_to_abs(ret) + get_dma_direct_offset(dev);
+
+ return ret;
+#endif
+}
+
+void dma_direct_free_coherent(struct device *dev, size_t size,
+ void *vaddr, dma_addr_t dma_handle)
+{
+#ifdef CONFIG_NOT_COHERENT_CACHE
+ __dma_free_coherent(size, vaddr);
+#else
+ free_pages((unsigned long)vaddr, get_order(size));
+#endif
+}
+
+static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
+ int nents, enum dma_data_direction direction,
+ struct dma_attrs *attrs)
+{
+ struct scatterlist *sg;
+ int i;
+
+ for_each_sg(sgl, sg, nents, i) {
+ sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev);
+ sg->dma_length = sg->length;
+ }
+
+ return nents;
+}
+
+static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
+ int nents, enum dma_data_direction direction,
+ struct dma_attrs *attrs)
+{
+}
+
+static int dma_direct_dma_supported(struct device *dev, u64 mask)
+{
+#ifdef CONFIG_PPC64
+ /* Could be improved to check for memory though it better be
+ * done via some global so platforms can set the limit in case
+ * they have limited DMA windows
+ */
+ return mask >= DMA_32BIT_MASK;
+#else
+ return 1;
+#endif
+}
+
+static inline dma_addr_t dma_direct_map_page(struct device *dev,
+ struct page *page,
+ unsigned long offset,
+ size_t size,
+ enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ BUG_ON(dir == DMA_NONE);
+ __dma_sync_page(page, offset, size, dir);
+ return page_to_phys(page) + offset + get_dma_direct_offset(dev);
+}
+
+static inline void dma_direct_unmap_page(struct device *dev,
+ dma_addr_t dma_address,
+ size_t size,
+ enum dma_data_direction direction,
+ struct dma_attrs *attrs)
+{
+}
+
+struct dma_mapping_ops dma_direct_ops = {
+ .alloc_coherent = dma_direct_alloc_coherent,
+ .free_coherent = dma_direct_free_coherent,
+ .map_sg = dma_direct_map_sg,
+ .unmap_sg = dma_direct_unmap_sg,
+ .dma_supported = dma_direct_dma_supported,
+ .map_page = dma_direct_map_page,
+ .unmap_page = dma_direct_unmap_page,
+};
+EXPORT_SYMBOL(dma_direct_ops);