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/dma-debug.h>
13 #include <asm/cacheflush.h>
16 * Generic direct DMA implementation
18 * This implementation supports a per-device offset that can be applied if
19 * the address at which memory is visible to devices is not 0. Platform code
20 * can set archdata.dma_data to an unsigned long holding the offset. By
21 * default the offset is PCI_DRAM_OFFSET.
23 static inline void __dma_sync_page(unsigned long paddr
, unsigned long offset
,
24 size_t size
, enum dma_data_direction direction
)
28 flush_dcache_range(paddr
+ offset
, paddr
+ offset
+ size
);
31 invalidate_dcache_range(paddr
+ offset
, paddr
+ offset
+ size
);
38 static unsigned long get_dma_direct_offset(struct device
*dev
)
41 return (unsigned long)dev
->archdata
.dma_data
;
43 return PCI_DRAM_OFFSET
; /* FIXME Not sure if is correct */
46 #define NOT_COHERENT_CACHE
48 static void *dma_direct_alloc_coherent(struct device
*dev
, size_t size
,
49 dma_addr_t
*dma_handle
, gfp_t flag
)
51 #ifdef NOT_COHERENT_CACHE
52 return consistent_alloc(flag
, size
, dma_handle
);
56 int node
= dev_to_node(dev
);
58 /* ignore region specifiers */
59 flag
&= ~(__GFP_HIGHMEM
);
61 page
= alloc_pages_node(node
, flag
, get_order(size
));
64 ret
= page_address(page
);
66 *dma_handle
= virt_to_phys(ret
) + get_dma_direct_offset(dev
);
72 static void dma_direct_free_coherent(struct device
*dev
, size_t size
,
73 void *vaddr
, dma_addr_t dma_handle
)
75 #ifdef NOT_COHERENT_CACHE
76 consistent_free(vaddr
);
78 free_pages((unsigned long)vaddr
, get_order(size
));
82 static int dma_direct_map_sg(struct device
*dev
, struct scatterlist
*sgl
,
83 int nents
, enum dma_data_direction direction
,
84 struct dma_attrs
*attrs
)
86 struct scatterlist
*sg
;
89 /* FIXME this part of code is untested */
90 for_each_sg(sgl
, sg
, nents
, i
) {
91 sg
->dma_address
= sg_phys(sg
) + get_dma_direct_offset(dev
);
92 sg
->dma_length
= sg
->length
;
93 __dma_sync_page(page_to_phys(sg_page(sg
)), sg
->offset
,
94 sg
->length
, direction
);
100 static void dma_direct_unmap_sg(struct device
*dev
, struct scatterlist
*sg
,
101 int nents
, enum dma_data_direction direction
,
102 struct dma_attrs
*attrs
)
106 static int dma_direct_dma_supported(struct device
*dev
, u64 mask
)
111 static inline dma_addr_t
dma_direct_map_page(struct device
*dev
,
113 unsigned long offset
,
115 enum dma_data_direction direction
,
116 struct dma_attrs
*attrs
)
118 __dma_sync_page(page_to_phys(page
), offset
, size
, direction
);
119 return page_to_phys(page
) + offset
+ get_dma_direct_offset(dev
);
122 static inline void dma_direct_unmap_page(struct device
*dev
,
123 dma_addr_t dma_address
,
125 enum dma_data_direction direction
,
126 struct dma_attrs
*attrs
)
128 /* There is not necessary to do cache cleanup
130 * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
131 * dma_address is physical address
133 __dma_sync_page(dma_address
, 0 , size
, direction
);
136 struct dma_map_ops dma_direct_ops
= {
137 .alloc_coherent
= dma_direct_alloc_coherent
,
138 .free_coherent
= dma_direct_free_coherent
,
139 .map_sg
= dma_direct_map_sg
,
140 .unmap_sg
= dma_direct_unmap_sg
,
141 .dma_supported
= dma_direct_dma_supported
,
142 .map_page
= dma_direct_map_page
,
143 .unmap_page
= dma_direct_unmap_page
,
145 EXPORT_SYMBOL(dma_direct_ops
);
147 /* Number of entries preallocated for DMA-API debugging */
148 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
150 static int __init
dma_init(void)
152 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES
);
156 fs_initcall(dma_init
);