2 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
4 * Provide default implementations of the DMA mapping callbacks for
5 * directly mapped busses and busses using the iommu infrastructure
8 #include <linux/device.h>
9 #include <linux/dma-mapping.h>
11 #include <asm/iommu.h>
12 #include <asm/abs_addr.h>
15 * Generic iommu implementation
18 static inline unsigned long device_to_mask(struct device *dev)
20 if (dev->dma_mask && *dev->dma_mask)
21 return *dev->dma_mask;
22 /* Assume devices without mask can take 32 bit addresses */
27 /* Allocates a contiguous real buffer and creates mappings over it.
28 * Returns the virtual address of the buffer and sets dma_handle
29 * to the dma address (mapping) of the first page.
31 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
32 dma_addr_t *dma_handle, gfp_t flag)
34 return iommu_alloc_coherent(dev, dev->archdata.dma_data, size,
35 dma_handle, device_to_mask(dev), flag,
36 dev->archdata.numa_node);
39 static void dma_iommu_free_coherent(struct device *dev, size_t size,
40 void *vaddr, dma_addr_t dma_handle)
42 iommu_free_coherent(dev->archdata.dma_data, size, vaddr, dma_handle);
45 /* Creates TCEs for a user provided buffer. The user buffer must be
46 * contiguous real kernel storage (not vmalloc). The address of the buffer
47 * passed here is the kernel (virtual) address of the buffer. The buffer
48 * need not be page aligned, the dma_addr_t returned will point to the same
49 * byte within the page as vaddr.
51 static dma_addr_t dma_iommu_map_single(struct device *dev, void *vaddr,
53 enum dma_data_direction direction,
54 struct dma_attrs *attrs)
56 return iommu_map_single(dev, dev->archdata.dma_data, vaddr, size,
57 device_to_mask(dev), direction, attrs);
61 static void dma_iommu_unmap_single(struct device *dev, dma_addr_t dma_handle,
63 enum dma_data_direction direction,
64 struct dma_attrs *attrs)
66 iommu_unmap_single(dev->archdata.dma_data, dma_handle, size, direction,
71 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
72 int nelems, enum dma_data_direction direction,
73 struct dma_attrs *attrs)
75 return iommu_map_sg(dev, dev->archdata.dma_data, sglist, nelems,
76 device_to_mask(dev), direction, attrs);
79 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
80 int nelems, enum dma_data_direction direction,
81 struct dma_attrs *attrs)
83 iommu_unmap_sg(dev->archdata.dma_data, sglist, nelems, direction,
87 /* We support DMA to/from any memory page via the iommu */
88 static int dma_iommu_dma_supported(struct device *dev, u64 mask)
90 struct iommu_table *tbl = dev->archdata.dma_data;
92 if (!tbl || tbl->it_offset > mask) {
94 "Warning: IOMMU offset too big for device mask\n");
97 "mask: 0x%08lx, table offset: 0x%08lx\n",
98 mask, tbl->it_offset);
100 printk(KERN_INFO "mask: 0x%08lx, table unavailable\n",
107 struct dma_mapping_ops dma_iommu_ops = {
108 .alloc_coherent = dma_iommu_alloc_coherent,
109 .free_coherent = dma_iommu_free_coherent,
110 .map_single = dma_iommu_map_single,
111 .unmap_single = dma_iommu_unmap_single,
112 .map_sg = dma_iommu_map_sg,
113 .unmap_sg = dma_iommu_unmap_sg,
114 .dma_supported = dma_iommu_dma_supported,
116 EXPORT_SYMBOL(dma_iommu_ops);
119 * Generic direct DMA implementation
121 * This implementation supports a per-device offset that can be applied if
122 * the address at which memory is visible to devices is not 0. Platform code
123 * can set archdata.dma_data to an unsigned long holding the offset. By
124 * default the offset is zero.
127 static unsigned long get_dma_direct_offset(struct device *dev)
129 return (unsigned long)dev->archdata.dma_data;
132 static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
133 dma_addr_t *dma_handle, gfp_t flag)
137 int node = dev->archdata.numa_node;
139 page = alloc_pages_node(node, flag, get_order(size));
142 ret = page_address(page);
143 memset(ret, 0, size);
144 *dma_handle = virt_to_abs(ret) + get_dma_direct_offset(dev);
149 static void dma_direct_free_coherent(struct device *dev, size_t size,
150 void *vaddr, dma_addr_t dma_handle)
152 free_pages((unsigned long)vaddr, get_order(size));
155 static dma_addr_t dma_direct_map_single(struct device *dev, void *ptr,
157 enum dma_data_direction direction,
158 struct dma_attrs *attrs)
160 return virt_to_abs(ptr) + get_dma_direct_offset(dev);
163 static void dma_direct_unmap_single(struct device *dev, dma_addr_t dma_addr,
165 enum dma_data_direction direction,
166 struct dma_attrs *attrs)
170 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
171 int nents, enum dma_data_direction direction,
172 struct dma_attrs *attrs)
174 struct scatterlist *sg;
177 for_each_sg(sgl, sg, nents, i) {
178 sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev);
179 sg->dma_length = sg->length;
185 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
186 int nents, enum dma_data_direction direction,
187 struct dma_attrs *attrs)
191 static int dma_direct_dma_supported(struct device *dev, u64 mask)
193 /* Could be improved to check for memory though it better be
194 * done via some global so platforms can set the limit in case
195 * they have limited DMA windows
197 return mask >= DMA_32BIT_MASK;
200 struct dma_mapping_ops dma_direct_ops = {
201 .alloc_coherent = dma_direct_alloc_coherent,
202 .free_coherent = dma_direct_free_coherent,
203 .map_single = dma_direct_map_single,
204 .unmap_single = dma_direct_unmap_single,
205 .map_sg = dma_direct_map_sg,
206 .unmap_sg = dma_direct_unmap_sg,
207 .dma_supported = dma_direct_dma_supported,
209 EXPORT_SYMBOL(dma_direct_ops);