1
2#ifndef SCATTERLIST_H
3#define SCATTERLIST_H
4#include <linux/kernel.h>
5
6struct scatterlist {
7 unsigned long page_link;
8 unsigned int offset;
9 unsigned int length;
10 dma_addr_t dma_address;
11};
12
13
14#define sg_is_chain(sg) ((sg)->page_link & 0x01)
15#define sg_is_last(sg) ((sg)->page_link & 0x02)
16#define sg_chain_ptr(sg) \
17 ((struct scatterlist *) ((sg)->page_link & ~0x03))
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28
29static inline void sg_assign_page(struct scatterlist *sg, struct page *page)
30{
31 unsigned long page_link = sg->page_link & 0x3;
32
33
34
35
36
37 BUG_ON((unsigned long) page & 0x03);
38#ifdef CONFIG_DEBUG_SG
39 BUG_ON(sg_is_chain(sg));
40#endif
41 sg->page_link = page_link | (unsigned long) page;
42}
43
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57
58static inline void sg_set_page(struct scatterlist *sg, struct page *page,
59 unsigned int len, unsigned int offset)
60{
61 sg_assign_page(sg, page);
62 sg->offset = offset;
63 sg->length = len;
64}
65
66static inline struct page *sg_page(struct scatterlist *sg)
67{
68#ifdef CONFIG_DEBUG_SG
69 BUG_ON(sg_is_chain(sg));
70#endif
71 return (struct page *)((sg)->page_link & ~0x3);
72}
73
74
75
76
77#define for_each_sg(sglist, sg, nr, __i) \
78 for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg))
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89
90static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents,
91 struct scatterlist *sgl)
92{
93
94
95
96 prv[prv_nents - 1].offset = 0;
97 prv[prv_nents - 1].length = 0;
98
99
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102
103 prv[prv_nents - 1].page_link = ((unsigned long) sgl | 0x01) & ~0x02;
104}
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114
115static inline void sg_mark_end(struct scatterlist *sg)
116{
117
118
119
120 sg->page_link |= 0x02;
121 sg->page_link &= ~0x01;
122}
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130
131
132static inline void sg_unmark_end(struct scatterlist *sg)
133{
134 sg->page_link &= ~0x02;
135}
136
137static inline struct scatterlist *sg_next(struct scatterlist *sg)
138{
139 if (sg_is_last(sg))
140 return NULL;
141
142 sg++;
143 if (unlikely(sg_is_chain(sg)))
144 sg = sg_chain_ptr(sg);
145
146 return sg;
147}
148
149static inline void sg_init_table(struct scatterlist *sgl, unsigned int nents)
150{
151 memset(sgl, 0, sizeof(*sgl) * nents);
152 sg_mark_end(&sgl[nents - 1]);
153}
154
155static inline dma_addr_t sg_phys(struct scatterlist *sg)
156{
157 return page_to_phys(sg_page(sg)) + sg->offset;
158}
159
160static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
161 unsigned int buflen)
162{
163 sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
164}
165
166static inline void sg_init_one(struct scatterlist *sg,
167 const void *buf, unsigned int buflen)
168{
169 sg_init_table(sg, 1);
170 sg_set_buf(sg, buf, buflen);
171}
172#endif
173