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1da177e4 LT |
1 | #ifndef _LINUX_SCATTERLIST_H |
2 | #define _LINUX_SCATTERLIST_H | |
3 | ||
187f1882 PG |
4 | #include <linux/string.h> |
5 | #include <linux/bug.h> | |
6 | #include <linux/mm.h> | |
7 | ||
85cdffcd | 8 | #include <asm/types.h> |
d32311fe | 9 | #include <asm/scatterlist.h> |
18dabf47 JA |
10 | #include <asm/io.h> |
11 | ||
0db9299f JA |
12 | struct sg_table { |
13 | struct scatterlist *sgl; /* the list */ | |
14 | unsigned int nents; /* number of mapped entries */ | |
15 | unsigned int orig_nents; /* original size of list */ | |
16 | }; | |
17 | ||
18dabf47 JA |
18 | /* |
19 | * Notes on SG table design. | |
20 | * | |
21 | * Architectures must provide an unsigned long page_link field in the | |
22 | * scatterlist struct. We use that to place the page pointer AND encode | |
23 | * information about the sg table as well. The two lower bits are reserved | |
24 | * for this information. | |
25 | * | |
26 | * If bit 0 is set, then the page_link contains a pointer to the next sg | |
27 | * table list. Otherwise the next entry is at sg + 1. | |
28 | * | |
29 | * If bit 1 is set, then this sg entry is the last element in a list. | |
30 | * | |
31 | * See sg_next(). | |
32 | * | |
33 | */ | |
1da177e4 | 34 | |
d6ec0842 JA |
35 | #define SG_MAGIC 0x87654321 |
36 | ||
645a8d94 TH |
37 | /* |
38 | * We overload the LSB of the page pointer to indicate whether it's | |
39 | * a valid sg entry, or whether it points to the start of a new scatterlist. | |
40 | * Those low bits are there for everyone! (thanks mason :-) | |
41 | */ | |
42 | #define sg_is_chain(sg) ((sg)->page_link & 0x01) | |
43 | #define sg_is_last(sg) ((sg)->page_link & 0x02) | |
44 | #define sg_chain_ptr(sg) \ | |
45 | ((struct scatterlist *) ((sg)->page_link & ~0x03)) | |
46 | ||
82f66fbe | 47 | /** |
642f1490 JA |
48 | * sg_assign_page - Assign a given page to an SG entry |
49 | * @sg: SG entry | |
50 | * @page: The page | |
82f66fbe JA |
51 | * |
52 | * Description: | |
642f1490 JA |
53 | * Assign page to sg entry. Also see sg_set_page(), the most commonly used |
54 | * variant. | |
82f66fbe JA |
55 | * |
56 | **/ | |
642f1490 | 57 | static inline void sg_assign_page(struct scatterlist *sg, struct page *page) |
82f66fbe | 58 | { |
18dabf47 JA |
59 | unsigned long page_link = sg->page_link & 0x3; |
60 | ||
de26103d JA |
61 | /* |
62 | * In order for the low bit stealing approach to work, pages | |
63 | * must be aligned at a 32-bit boundary as a minimum. | |
64 | */ | |
65 | BUG_ON((unsigned long) page & 0x03); | |
d6ec0842 JA |
66 | #ifdef CONFIG_DEBUG_SG |
67 | BUG_ON(sg->sg_magic != SG_MAGIC); | |
645a8d94 | 68 | BUG_ON(sg_is_chain(sg)); |
d6ec0842 | 69 | #endif |
18dabf47 | 70 | sg->page_link = page_link | (unsigned long) page; |
82f66fbe JA |
71 | } |
72 | ||
642f1490 JA |
73 | /** |
74 | * sg_set_page - Set sg entry to point at given page | |
75 | * @sg: SG entry | |
76 | * @page: The page | |
77 | * @len: Length of data | |
78 | * @offset: Offset into page | |
79 | * | |
80 | * Description: | |
81 | * Use this function to set an sg entry pointing at a page, never assign | |
82 | * the page directly. We encode sg table information in the lower bits | |
83 | * of the page pointer. See sg_page() for looking up the page belonging | |
84 | * to an sg entry. | |
85 | * | |
86 | **/ | |
87 | static inline void sg_set_page(struct scatterlist *sg, struct page *page, | |
88 | unsigned int len, unsigned int offset) | |
89 | { | |
90 | sg_assign_page(sg, page); | |
91 | sg->offset = offset; | |
92 | sg->length = len; | |
93 | } | |
94 | ||
645a8d94 TH |
95 | static inline struct page *sg_page(struct scatterlist *sg) |
96 | { | |
97 | #ifdef CONFIG_DEBUG_SG | |
98 | BUG_ON(sg->sg_magic != SG_MAGIC); | |
99 | BUG_ON(sg_is_chain(sg)); | |
100 | #endif | |
101 | return (struct page *)((sg)->page_link & ~0x3); | |
102 | } | |
82f66fbe | 103 | |
18dabf47 JA |
104 | /** |
105 | * sg_set_buf - Set sg entry to point at given data | |
106 | * @sg: SG entry | |
107 | * @buf: Data | |
108 | * @buflen: Data length | |
109 | * | |
110 | **/ | |
03fd9cee | 111 | static inline void sg_set_buf(struct scatterlist *sg, const void *buf, |
d32311fe HX |
112 | unsigned int buflen) |
113 | { | |
ac4e97ab RR |
114 | #ifdef CONFIG_DEBUG_SG |
115 | BUG_ON(!virt_addr_valid(buf)); | |
116 | #endif | |
642f1490 | 117 | sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf)); |
1da177e4 LT |
118 | } |
119 | ||
96b418c9 JA |
120 | /* |
121 | * Loop over each sg element, following the pointer to a new list if necessary | |
122 | */ | |
123 | #define for_each_sg(sglist, sg, nr, __i) \ | |
124 | for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg)) | |
125 | ||
70eb8040 JA |
126 | /** |
127 | * sg_chain - Chain two sglists together | |
128 | * @prv: First scatterlist | |
129 | * @prv_nents: Number of entries in prv | |
130 | * @sgl: Second scatterlist | |
131 | * | |
18dabf47 JA |
132 | * Description: |
133 | * Links @prv@ and @sgl@ together, to form a longer scatterlist. | |
70eb8040 | 134 | * |
18dabf47 | 135 | **/ |
70eb8040 JA |
136 | static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, |
137 | struct scatterlist *sgl) | |
138 | { | |
308c09f1 | 139 | #ifndef CONFIG_ARCH_HAS_SG_CHAIN |
70eb8040 JA |
140 | BUG(); |
141 | #endif | |
645a8d94 TH |
142 | |
143 | /* | |
144 | * offset and length are unused for chain entry. Clear them. | |
145 | */ | |
b801a1e7 RR |
146 | prv[prv_nents - 1].offset = 0; |
147 | prv[prv_nents - 1].length = 0; | |
645a8d94 | 148 | |
73fd546a JA |
149 | /* |
150 | * Set lowest bit to indicate a link pointer, and make sure to clear | |
151 | * the termination bit if it happens to be set. | |
152 | */ | |
153 | prv[prv_nents - 1].page_link = ((unsigned long) sgl | 0x01) & ~0x02; | |
70eb8040 JA |
154 | } |
155 | ||
82f66fbe JA |
156 | /** |
157 | * sg_mark_end - Mark the end of the scatterlist | |
c46f2334 | 158 | * @sg: SG entryScatterlist |
82f66fbe JA |
159 | * |
160 | * Description: | |
c46f2334 JA |
161 | * Marks the passed in sg entry as the termination point for the sg |
162 | * table. A call to sg_next() on this entry will return NULL. | |
82f66fbe JA |
163 | * |
164 | **/ | |
c46f2334 | 165 | static inline void sg_mark_end(struct scatterlist *sg) |
82f66fbe | 166 | { |
c46f2334 JA |
167 | #ifdef CONFIG_DEBUG_SG |
168 | BUG_ON(sg->sg_magic != SG_MAGIC); | |
169 | #endif | |
170 | /* | |
171 | * Set termination bit, clear potential chain bit | |
172 | */ | |
18dabf47 | 173 | sg->page_link |= 0x02; |
c46f2334 | 174 | sg->page_link &= ~0x01; |
82f66fbe JA |
175 | } |
176 | ||
c8164d89 PB |
177 | /** |
178 | * sg_unmark_end - Undo setting the end of the scatterlist | |
179 | * @sg: SG entryScatterlist | |
180 | * | |
181 | * Description: | |
182 | * Removes the termination marker from the given entry of the scatterlist. | |
183 | * | |
184 | **/ | |
185 | static inline void sg_unmark_end(struct scatterlist *sg) | |
186 | { | |
187 | #ifdef CONFIG_DEBUG_SG | |
188 | BUG_ON(sg->sg_magic != SG_MAGIC); | |
189 | #endif | |
190 | sg->page_link &= ~0x02; | |
191 | } | |
192 | ||
82f66fbe JA |
193 | /** |
194 | * sg_phys - Return physical address of an sg entry | |
195 | * @sg: SG entry | |
196 | * | |
197 | * Description: | |
198 | * This calls page_to_phys() on the page in this sg entry, and adds the | |
199 | * sg offset. The caller must know that it is legal to call page_to_phys() | |
200 | * on the sg page. | |
201 | * | |
202 | **/ | |
85cdffcd | 203 | static inline dma_addr_t sg_phys(struct scatterlist *sg) |
82f66fbe JA |
204 | { |
205 | return page_to_phys(sg_page(sg)) + sg->offset; | |
206 | } | |
207 | ||
208 | /** | |
209 | * sg_virt - Return virtual address of an sg entry | |
18dabf47 | 210 | * @sg: SG entry |
82f66fbe JA |
211 | * |
212 | * Description: | |
213 | * This calls page_address() on the page in this sg entry, and adds the | |
214 | * sg offset. The caller must know that the sg page has a valid virtual | |
215 | * mapping. | |
216 | * | |
217 | **/ | |
218 | static inline void *sg_virt(struct scatterlist *sg) | |
219 | { | |
220 | return page_address(sg_page(sg)) + sg->offset; | |
221 | } | |
222 | ||
2e484610 | 223 | int sg_nents(struct scatterlist *sg); |
0db9299f JA |
224 | struct scatterlist *sg_next(struct scatterlist *); |
225 | struct scatterlist *sg_last(struct scatterlist *s, unsigned int); | |
226 | void sg_init_table(struct scatterlist *, unsigned int); | |
227 | void sg_init_one(struct scatterlist *, const void *, unsigned int); | |
228 | ||
229 | typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t); | |
230 | typedef void (sg_free_fn)(struct scatterlist *, unsigned int); | |
231 | ||
c53c6d6a | 232 | void __sg_free_table(struct sg_table *, unsigned int, bool, sg_free_fn *); |
0db9299f | 233 | void sg_free_table(struct sg_table *); |
c53c6d6a CH |
234 | int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, |
235 | struct scatterlist *, gfp_t, sg_alloc_fn *); | |
0db9299f | 236 | int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); |
efc42bc9 TS |
237 | int sg_alloc_table_from_pages(struct sg_table *sgt, |
238 | struct page **pages, unsigned int n_pages, | |
239 | unsigned long offset, unsigned long size, | |
240 | gfp_t gfp_mask); | |
0db9299f | 241 | |
b1adaf65 FT |
242 | size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
243 | void *buf, size_t buflen); | |
244 | size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, | |
245 | void *buf, size_t buflen); | |
246 | ||
df642cea AM |
247 | size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
248 | void *buf, size_t buflen, off_t skip); | |
249 | size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, | |
250 | void *buf, size_t buflen, off_t skip); | |
251 | ||
0db9299f JA |
252 | /* |
253 | * Maximum number of entries that will be allocated in one piece, if | |
254 | * a list larger than this is required then chaining will be utilized. | |
255 | */ | |
256 | #define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist)) | |
257 | ||
a321e91b ID |
258 | /* |
259 | * sg page iterator | |
260 | * | |
261 | * Iterates over sg entries page-by-page. On each successful iteration, | |
2db76d7c ID |
262 | * you can call sg_page_iter_page(@piter) and sg_page_iter_dma_address(@piter) |
263 | * to get the current page and its dma address. @piter->sg will point to the | |
264 | * sg holding this page and @piter->sg_pgoffset to the page's page offset | |
265 | * within the sg. The iteration will stop either when a maximum number of sg | |
266 | * entries was reached or a terminating sg (sg_last(sg) == true) was reached. | |
a321e91b ID |
267 | */ |
268 | struct sg_page_iter { | |
a321e91b ID |
269 | struct scatterlist *sg; /* sg holding the page */ |
270 | unsigned int sg_pgoffset; /* page offset within the sg */ | |
271 | ||
272 | /* these are internal states, keep away */ | |
273 | unsigned int __nents; /* remaining sg entries */ | |
274 | int __pg_advance; /* nr pages to advance at the | |
275 | * next step */ | |
276 | }; | |
277 | ||
278 | bool __sg_page_iter_next(struct sg_page_iter *piter); | |
279 | void __sg_page_iter_start(struct sg_page_iter *piter, | |
280 | struct scatterlist *sglist, unsigned int nents, | |
281 | unsigned long pgoffset); | |
2db76d7c ID |
282 | /** |
283 | * sg_page_iter_page - get the current page held by the page iterator | |
284 | * @piter: page iterator holding the page | |
285 | */ | |
286 | static inline struct page *sg_page_iter_page(struct sg_page_iter *piter) | |
287 | { | |
288 | return nth_page(sg_page(piter->sg), piter->sg_pgoffset); | |
289 | } | |
290 | ||
291 | /** | |
292 | * sg_page_iter_dma_address - get the dma address of the current page held by | |
293 | * the page iterator. | |
294 | * @piter: page iterator holding the page | |
295 | */ | |
296 | static inline dma_addr_t sg_page_iter_dma_address(struct sg_page_iter *piter) | |
297 | { | |
298 | return sg_dma_address(piter->sg) + (piter->sg_pgoffset << PAGE_SHIFT); | |
299 | } | |
a321e91b ID |
300 | |
301 | /** | |
302 | * for_each_sg_page - iterate over the pages of the given sg list | |
303 | * @sglist: sglist to iterate over | |
304 | * @piter: page iterator to hold current page, sg, sg_pgoffset | |
305 | * @nents: maximum number of sg entries to iterate over | |
306 | * @pgoffset: starting page offset | |
307 | */ | |
308 | #define for_each_sg_page(sglist, piter, nents, pgoffset) \ | |
309 | for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \ | |
310 | __sg_page_iter_next(piter);) | |
137d3edb TH |
311 | |
312 | /* | |
313 | * Mapping sg iterator | |
314 | * | |
315 | * Iterates over sg entries mapping page-by-page. On each successful | |
316 | * iteration, @miter->page points to the mapped page and | |
317 | * @miter->length bytes of data can be accessed at @miter->addr. As | |
318 | * long as an interation is enclosed between start and stop, the user | |
319 | * is free to choose control structure and when to stop. | |
320 | * | |
321 | * @miter->consumed is set to @miter->length on each iteration. It | |
322 | * can be adjusted if the user can't consume all the bytes in one go. | |
323 | * Also, a stopped iteration can be resumed by calling next on it. | |
324 | * This is useful when iteration needs to release all resources and | |
325 | * continue later (e.g. at the next interrupt). | |
326 | */ | |
327 | ||
328 | #define SG_MITER_ATOMIC (1 << 0) /* use kmap_atomic */ | |
6de7e356 SAS |
329 | #define SG_MITER_TO_SG (1 << 1) /* flush back to phys on unmap */ |
330 | #define SG_MITER_FROM_SG (1 << 2) /* nop */ | |
137d3edb TH |
331 | |
332 | struct sg_mapping_iter { | |
333 | /* the following three fields can be accessed directly */ | |
334 | struct page *page; /* currently mapped page */ | |
335 | void *addr; /* pointer to the mapped area */ | |
336 | size_t length; /* length of the mapped area */ | |
337 | size_t consumed; /* number of consumed bytes */ | |
4225fc85 | 338 | struct sg_page_iter piter; /* page iterator */ |
137d3edb TH |
339 | |
340 | /* these are internal states, keep away */ | |
4225fc85 ID |
341 | unsigned int __offset; /* offset within page */ |
342 | unsigned int __remaining; /* remaining bytes on page */ | |
137d3edb TH |
343 | unsigned int __flags; |
344 | }; | |
345 | ||
346 | void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, | |
347 | unsigned int nents, unsigned int flags); | |
0d6077f8 | 348 | bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset); |
137d3edb TH |
349 | bool sg_miter_next(struct sg_mapping_iter *miter); |
350 | void sg_miter_stop(struct sg_mapping_iter *miter); | |
351 | ||
1da177e4 | 352 | #endif /* _LINUX_SCATTERLIST_H */ |