1/*
2 * Copyright (C) 2009-2010 PetaLogix
3 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
4 *
5 * Provide default implementations of the DMA mapping callbacks for
6 * directly mapped busses.
7 */
8
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>
15
16#define NOT_COHERENT_CACHE
17
18static 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)
21{
22#ifdef NOT_COHERENT_CACHE
23	return consistent_alloc(flag, size, dma_handle);
24#else
25	void *ret;
26	struct page *page;
27	int node = dev_to_node(dev);
28
29	/* ignore region specifiers */
30	flag  &= ~(__GFP_HIGHMEM);
31
32	page = alloc_pages_node(node, flag, get_order(size));
33	if (page == NULL)
34		return NULL;
35	ret = page_address(page);
36	memset(ret, 0, size);
37	*dma_handle = virt_to_phys(ret);
38
39	return ret;
40#endif
41}
42
43static void dma_direct_free_coherent(struct device *dev, size_t size,
44				     void *vaddr, dma_addr_t dma_handle,
45				     struct dma_attrs *attrs)
46{
47#ifdef NOT_COHERENT_CACHE
48	consistent_free(size, vaddr);
49#else
50	free_pages((unsigned long)vaddr, get_order(size));
51#endif
52}
53
54static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
55			     int nents, enum dma_data_direction direction,
56			     struct dma_attrs *attrs)
57{
58	struct scatterlist *sg;
59	int i;
60
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);
66	}
67
68	return nents;
69}
70
71static int dma_direct_dma_supported(struct device *dev, u64 mask)
72{
73	return 1;
74}
75
76static inline dma_addr_t dma_direct_map_page(struct device *dev,
77					     struct page *page,
78					     unsigned long offset,
79					     size_t size,
80					     enum dma_data_direction direction,
81					     struct dma_attrs *attrs)
82{
83	__dma_sync(page_to_phys(page) + offset, size, direction);
84	return page_to_phys(page) + offset;
85}
86
87static inline void dma_direct_unmap_page(struct device *dev,
88					 dma_addr_t dma_address,
89					 size_t size,
90					 enum dma_data_direction direction,
91					 struct dma_attrs *attrs)
92{
93/* There is not necessary to do cache cleanup
94 *
95 * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
96 * dma_address is physical address
97 */
98	__dma_sync(dma_address, size, direction);
99}
100
101static inline void
102dma_direct_sync_single_for_cpu(struct device *dev,
103			       dma_addr_t dma_handle, size_t size,
104			       enum dma_data_direction direction)
105{
106	/*
107	 * It's pointless to flush the cache as the memory segment
108	 * is given to the CPU
109	 */
110
111	if (direction == DMA_FROM_DEVICE)
112		__dma_sync(dma_handle, size, direction);
113}
114
115static inline void
116dma_direct_sync_single_for_device(struct device *dev,
117				  dma_addr_t dma_handle, size_t size,
118				  enum dma_data_direction direction)
119{
120	/*
121	 * It's pointless to invalidate the cache if the device isn't
122	 * supposed to write to the relevant region
123	 */
124
125	if (direction == DMA_TO_DEVICE)
126		__dma_sync(dma_handle, size, direction);
127}
128
129static inline void
130dma_direct_sync_sg_for_cpu(struct device *dev,
131			   struct scatterlist *sgl, int nents,
132			   enum dma_data_direction direction)
133{
134	struct scatterlist *sg;
135	int i;
136
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);
141}
142
143static inline void
144dma_direct_sync_sg_for_device(struct device *dev,
145			      struct scatterlist *sgl, int nents,
146			      enum dma_data_direction direction)
147{
148	struct scatterlist *sg;
149	int i;
150
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);
155}
156
157static
158int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
159			     void *cpu_addr, dma_addr_t handle, size_t size,
160			     struct dma_attrs *attrs)
161{
162#ifdef CONFIG_MMU
163	unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
164	unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
165	unsigned long off = vma->vm_pgoff;
166	unsigned long pfn;
167
168	if (off >= count || user_count > (count - off))
169		return -ENXIO;
170
171#ifdef NOT_COHERENT_CACHE
172	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
173	pfn = consistent_virt_to_pfn(cpu_addr);
174#else
175	pfn = virt_to_pfn(cpu_addr);
176#endif
177	return remap_pfn_range(vma, vma->vm_start, pfn + off,
178			       vma->vm_end - vma->vm_start, vma->vm_page_prot);
179#else
180	return -ENXIO;
181#endif
182}
183
184struct dma_map_ops dma_direct_ops = {
185	.alloc		= dma_direct_alloc_coherent,
186	.free		= dma_direct_free_coherent,
187	.mmap		= dma_direct_mmap_coherent,
188	.map_sg		= dma_direct_map_sg,
189	.dma_supported	= dma_direct_dma_supported,
190	.map_page	= dma_direct_map_page,
191	.unmap_page	= dma_direct_unmap_page,
192	.sync_single_for_cpu		= dma_direct_sync_single_for_cpu,
193	.sync_single_for_device		= dma_direct_sync_single_for_device,
194	.sync_sg_for_cpu		= dma_direct_sync_sg_for_cpu,
195	.sync_sg_for_device		= dma_direct_sync_sg_for_device,
196};
197EXPORT_SYMBOL(dma_direct_ops);
198
199/* Number of entries preallocated for DMA-API debugging */
200#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
201
202static int __init dma_init(void)
203{
204	dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
205
206	return 0;
207}
208fs_initcall(dma_init);
209