2 * Copyright (C) 2009-2010 PetaLogix
3 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
5 * Provide default implementations of the DMA mapping callbacks for
6 * directly mapped busses.
9 #include <linux/device.h>
10 #include <linux/dma-mapping.h>
11 #include <linux/gfp.h>
12 #include <linux/dma-debug.h>
13 #include <linux/export.h>
14 #include <linux/bug.h>
16 #define NOT_COHERENT_CACHE
18 static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
19 dma_addr_t *dma_handle, gfp_t flag,
20 struct dma_attrs *attrs)
22 #ifdef NOT_COHERENT_CACHE
23 return consistent_alloc(flag, size, dma_handle);
27 int node = dev_to_node(dev);
29 /* ignore region specifiers */
30 flag &= ~(__GFP_HIGHMEM);
32 page = alloc_pages_node(node, flag, get_order(size));
35 ret = page_address(page);
37 *dma_handle = virt_to_phys(ret);
43 static void dma_direct_free_coherent(struct device *dev, size_t size,
44 void *vaddr, dma_addr_t dma_handle,
45 struct dma_attrs *attrs)
47 #ifdef NOT_COHERENT_CACHE
48 consistent_free(size, vaddr);
50 free_pages((unsigned long)vaddr, get_order(size));
54 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
55 int nents, enum dma_data_direction direction,
56 struct dma_attrs *attrs)
58 struct scatterlist *sg;
61 /* FIXME this part of code is untested */
62 for_each_sg(sgl, sg, nents, i) {
63 sg->dma_address = sg_phys(sg);
64 __dma_sync(page_to_phys(sg_page(sg)) + sg->offset,
65 sg->length, direction);
71 static int dma_direct_dma_supported(struct device *dev, u64 mask)
76 static inline dma_addr_t dma_direct_map_page(struct device *dev,
80 enum dma_data_direction direction,
81 struct dma_attrs *attrs)
83 __dma_sync(page_to_phys(page) + offset, size, direction);
84 return page_to_phys(page) + offset;
87 static inline void dma_direct_unmap_page(struct device *dev,
88 dma_addr_t dma_address,
90 enum dma_data_direction direction,
91 struct dma_attrs *attrs)
93 /* There is not necessary to do cache cleanup
95 * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
96 * dma_address is physical address
98 __dma_sync(dma_address, size, direction);
102 dma_direct_sync_single_for_cpu(struct device *dev,
103 dma_addr_t dma_handle, size_t size,
104 enum dma_data_direction direction)
107 * It's pointless to flush the cache as the memory segment
108 * is given to the CPU
111 if (direction == DMA_FROM_DEVICE)
112 __dma_sync(dma_handle, size, direction);
116 dma_direct_sync_single_for_device(struct device *dev,
117 dma_addr_t dma_handle, size_t size,
118 enum dma_data_direction direction)
121 * It's pointless to invalidate the cache if the device isn't
122 * supposed to write to the relevant region
125 if (direction == DMA_TO_DEVICE)
126 __dma_sync(dma_handle, size, direction);
130 dma_direct_sync_sg_for_cpu(struct device *dev,
131 struct scatterlist *sgl, int nents,
132 enum dma_data_direction direction)
134 struct scatterlist *sg;
137 /* FIXME this part of code is untested */
138 if (direction == DMA_FROM_DEVICE)
139 for_each_sg(sgl, sg, nents, i)
140 __dma_sync(sg->dma_address, sg->length, direction);
144 dma_direct_sync_sg_for_device(struct device *dev,
145 struct scatterlist *sgl, int nents,
146 enum dma_data_direction direction)
148 struct scatterlist *sg;
151 /* FIXME this part of code is untested */
152 if (direction == DMA_TO_DEVICE)
153 for_each_sg(sgl, sg, nents, i)
154 __dma_sync(sg->dma_address, sg->length, direction);
157 struct dma_map_ops dma_direct_ops = {
158 .alloc = dma_direct_alloc_coherent,
159 .free = dma_direct_free_coherent,
160 .map_sg = dma_direct_map_sg,
161 .dma_supported = dma_direct_dma_supported,
162 .map_page = dma_direct_map_page,
163 .unmap_page = dma_direct_unmap_page,
164 .sync_single_for_cpu = dma_direct_sync_single_for_cpu,
165 .sync_single_for_device = dma_direct_sync_single_for_device,
166 .sync_sg_for_cpu = dma_direct_sync_sg_for_cpu,
167 .sync_sg_for_device = dma_direct_sync_sg_for_device,
169 EXPORT_SYMBOL(dma_direct_ops);
171 /* Number of entries preallocated for DMA-API debugging */
172 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
174 static int __init dma_init(void)
176 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
180 fs_initcall(dma_init);