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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef _LINUX_SCATTERLIST_H |
3 | #define _LINUX_SCATTERLIST_H | |
4 | ||
187f1882 | 5 | #include <linux/string.h> |
84be456f | 6 | #include <linux/types.h> |
187f1882 PG |
7 | #include <linux/bug.h> |
8 | #include <linux/mm.h> | |
18dabf47 JA |
9 | #include <asm/io.h> |
10 | ||
84be456f | 11 | struct scatterlist { |
84be456f CH |
12 | unsigned long page_link; |
13 | unsigned int offset; | |
14 | unsigned int length; | |
15 | dma_addr_t dma_address; | |
16 | #ifdef CONFIG_NEED_SG_DMA_LENGTH | |
17 | unsigned int dma_length; | |
18 | #endif | |
19 | }; | |
20 | ||
21 | /* | |
22 | * These macros should be used after a dma_map_sg call has been done | |
23 | * to get bus addresses of each of the SG entries and their lengths. | |
24 | * You should only work with the number of sg entries dma_map_sg | |
25 | * returns, or alternatively stop on the first sg_dma_len(sg) which | |
26 | * is 0. | |
27 | */ | |
28 | #define sg_dma_address(sg) ((sg)->dma_address) | |
29 | ||
30 | #ifdef CONFIG_NEED_SG_DMA_LENGTH | |
31 | #define sg_dma_len(sg) ((sg)->dma_length) | |
32 | #else | |
33 | #define sg_dma_len(sg) ((sg)->length) | |
34 | #endif | |
35 | ||
0db9299f JA |
36 | struct sg_table { |
37 | struct scatterlist *sgl; /* the list */ | |
38 | unsigned int nents; /* number of mapped entries */ | |
39 | unsigned int orig_nents; /* original size of list */ | |
40 | }; | |
41 | ||
3e302dbc MG |
42 | struct sg_append_table { |
43 | struct sg_table sgt; /* The scatter list table */ | |
44 | struct scatterlist *prv; /* last populated sge in the table */ | |
45 | unsigned int total_nents; /* Total entries in the table */ | |
46 | }; | |
47 | ||
18dabf47 JA |
48 | /* |
49 | * Notes on SG table design. | |
50 | * | |
84be456f CH |
51 | * We use the unsigned long page_link field in the scatterlist struct to place |
52 | * the page pointer AND encode information about the sg table as well. The two | |
53 | * lower bits are reserved for this information. | |
18dabf47 JA |
54 | * |
55 | * If bit 0 is set, then the page_link contains a pointer to the next sg | |
56 | * table list. Otherwise the next entry is at sg + 1. | |
57 | * | |
58 | * If bit 1 is set, then this sg entry is the last element in a list. | |
59 | * | |
60 | * See sg_next(). | |
61 | * | |
62 | */ | |
1da177e4 | 63 | |
723fbf56 AK |
64 | #define SG_CHAIN 0x01UL |
65 | #define SG_END 0x02UL | |
d6ec0842 | 66 | |
645a8d94 TH |
67 | /* |
68 | * We overload the LSB of the page pointer to indicate whether it's | |
69 | * a valid sg entry, or whether it points to the start of a new scatterlist. | |
70 | * Those low bits are there for everyone! (thanks mason :-) | |
71 | */ | |
f857acfc LG |
72 | #define SG_PAGE_LINK_MASK (SG_CHAIN | SG_END) |
73 | ||
74 | static inline unsigned int __sg_flags(struct scatterlist *sg) | |
75 | { | |
76 | return sg->page_link & SG_PAGE_LINK_MASK; | |
77 | } | |
78 | ||
79 | static inline struct scatterlist *sg_chain_ptr(struct scatterlist *sg) | |
80 | { | |
81 | return (struct scatterlist *)(sg->page_link & ~SG_PAGE_LINK_MASK); | |
82 | } | |
83 | ||
84 | static inline bool sg_is_chain(struct scatterlist *sg) | |
85 | { | |
86 | return __sg_flags(sg) & SG_CHAIN; | |
87 | } | |
88 | ||
89 | static inline bool sg_is_last(struct scatterlist *sg) | |
90 | { | |
91 | return __sg_flags(sg) & SG_END; | |
92 | } | |
645a8d94 | 93 | |
82f66fbe | 94 | /** |
642f1490 JA |
95 | * sg_assign_page - Assign a given page to an SG entry |
96 | * @sg: SG entry | |
97 | * @page: The page | |
82f66fbe JA |
98 | * |
99 | * Description: | |
642f1490 JA |
100 | * Assign page to sg entry. Also see sg_set_page(), the most commonly used |
101 | * variant. | |
82f66fbe JA |
102 | * |
103 | **/ | |
642f1490 | 104 | static inline void sg_assign_page(struct scatterlist *sg, struct page *page) |
82f66fbe | 105 | { |
723fbf56 | 106 | unsigned long page_link = sg->page_link & (SG_CHAIN | SG_END); |
18dabf47 | 107 | |
de26103d JA |
108 | /* |
109 | * In order for the low bit stealing approach to work, pages | |
110 | * must be aligned at a 32-bit boundary as a minimum. | |
111 | */ | |
f857acfc | 112 | BUG_ON((unsigned long)page & SG_PAGE_LINK_MASK); |
d6ec0842 | 113 | #ifdef CONFIG_DEBUG_SG |
645a8d94 | 114 | BUG_ON(sg_is_chain(sg)); |
d6ec0842 | 115 | #endif |
18dabf47 | 116 | sg->page_link = page_link | (unsigned long) page; |
82f66fbe JA |
117 | } |
118 | ||
642f1490 JA |
119 | /** |
120 | * sg_set_page - Set sg entry to point at given page | |
121 | * @sg: SG entry | |
122 | * @page: The page | |
123 | * @len: Length of data | |
124 | * @offset: Offset into page | |
125 | * | |
126 | * Description: | |
127 | * Use this function to set an sg entry pointing at a page, never assign | |
128 | * the page directly. We encode sg table information in the lower bits | |
129 | * of the page pointer. See sg_page() for looking up the page belonging | |
130 | * to an sg entry. | |
131 | * | |
132 | **/ | |
133 | static inline void sg_set_page(struct scatterlist *sg, struct page *page, | |
134 | unsigned int len, unsigned int offset) | |
135 | { | |
136 | sg_assign_page(sg, page); | |
137 | sg->offset = offset; | |
138 | sg->length = len; | |
139 | } | |
140 | ||
645a8d94 TH |
141 | static inline struct page *sg_page(struct scatterlist *sg) |
142 | { | |
143 | #ifdef CONFIG_DEBUG_SG | |
645a8d94 TH |
144 | BUG_ON(sg_is_chain(sg)); |
145 | #endif | |
f857acfc | 146 | return (struct page *)((sg)->page_link & ~SG_PAGE_LINK_MASK); |
645a8d94 | 147 | } |
82f66fbe | 148 | |
18dabf47 JA |
149 | /** |
150 | * sg_set_buf - Set sg entry to point at given data | |
151 | * @sg: SG entry | |
152 | * @buf: Data | |
153 | * @buflen: Data length | |
154 | * | |
155 | **/ | |
03fd9cee | 156 | static inline void sg_set_buf(struct scatterlist *sg, const void *buf, |
d32311fe HX |
157 | unsigned int buflen) |
158 | { | |
ac4e97ab RR |
159 | #ifdef CONFIG_DEBUG_SG |
160 | BUG_ON(!virt_addr_valid(buf)); | |
161 | #endif | |
642f1490 | 162 | sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf)); |
1da177e4 LT |
163 | } |
164 | ||
96b418c9 JA |
165 | /* |
166 | * Loop over each sg element, following the pointer to a new list if necessary | |
167 | */ | |
168 | #define for_each_sg(sglist, sg, nr, __i) \ | |
169 | for (__i = 0, sg = (sglist); __i < (nr); __i++, sg = sg_next(sg)) | |
170 | ||
709d6d73 MS |
171 | /* |
172 | * Loop over each sg element in the given sg_table object. | |
173 | */ | |
174 | #define for_each_sgtable_sg(sgt, sg, i) \ | |
68d23705 | 175 | for_each_sg((sgt)->sgl, sg, (sgt)->orig_nents, i) |
709d6d73 MS |
176 | |
177 | /* | |
178 | * Loop over each sg element in the given *DMA mapped* sg_table object. | |
179 | * Please use sg_dma_address(sg) and sg_dma_len(sg) to extract DMA addresses | |
180 | * of the each element. | |
181 | */ | |
182 | #define for_each_sgtable_dma_sg(sgt, sg, i) \ | |
68d23705 | 183 | for_each_sg((sgt)->sgl, sg, (sgt)->nents, i) |
709d6d73 | 184 | |
07da1223 MG |
185 | static inline void __sg_chain(struct scatterlist *chain_sg, |
186 | struct scatterlist *sgl) | |
187 | { | |
188 | /* | |
189 | * offset and length are unused for chain entry. Clear them. | |
190 | */ | |
191 | chain_sg->offset = 0; | |
192 | chain_sg->length = 0; | |
193 | ||
194 | /* | |
195 | * Set lowest bit to indicate a link pointer, and make sure to clear | |
196 | * the termination bit if it happens to be set. | |
197 | */ | |
198 | chain_sg->page_link = ((unsigned long) sgl | SG_CHAIN) & ~SG_END; | |
199 | } | |
200 | ||
70eb8040 JA |
201 | /** |
202 | * sg_chain - Chain two sglists together | |
203 | * @prv: First scatterlist | |
204 | * @prv_nents: Number of entries in prv | |
205 | * @sgl: Second scatterlist | |
206 | * | |
18dabf47 JA |
207 | * Description: |
208 | * Links @prv@ and @sgl@ together, to form a longer scatterlist. | |
70eb8040 | 209 | * |
18dabf47 | 210 | **/ |
70eb8040 JA |
211 | static inline void sg_chain(struct scatterlist *prv, unsigned int prv_nents, |
212 | struct scatterlist *sgl) | |
213 | { | |
07da1223 | 214 | __sg_chain(&prv[prv_nents - 1], sgl); |
70eb8040 JA |
215 | } |
216 | ||
82f66fbe JA |
217 | /** |
218 | * sg_mark_end - Mark the end of the scatterlist | |
c46f2334 | 219 | * @sg: SG entryScatterlist |
82f66fbe JA |
220 | * |
221 | * Description: | |
c46f2334 JA |
222 | * Marks the passed in sg entry as the termination point for the sg |
223 | * table. A call to sg_next() on this entry will return NULL. | |
82f66fbe JA |
224 | * |
225 | **/ | |
c46f2334 | 226 | static inline void sg_mark_end(struct scatterlist *sg) |
82f66fbe | 227 | { |
c46f2334 JA |
228 | /* |
229 | * Set termination bit, clear potential chain bit | |
230 | */ | |
723fbf56 AK |
231 | sg->page_link |= SG_END; |
232 | sg->page_link &= ~SG_CHAIN; | |
82f66fbe JA |
233 | } |
234 | ||
c8164d89 PB |
235 | /** |
236 | * sg_unmark_end - Undo setting the end of the scatterlist | |
237 | * @sg: SG entryScatterlist | |
238 | * | |
239 | * Description: | |
240 | * Removes the termination marker from the given entry of the scatterlist. | |
241 | * | |
242 | **/ | |
243 | static inline void sg_unmark_end(struct scatterlist *sg) | |
244 | { | |
723fbf56 | 245 | sg->page_link &= ~SG_END; |
c8164d89 PB |
246 | } |
247 | ||
82f66fbe JA |
248 | /** |
249 | * sg_phys - Return physical address of an sg entry | |
250 | * @sg: SG entry | |
251 | * | |
252 | * Description: | |
253 | * This calls page_to_phys() on the page in this sg entry, and adds the | |
254 | * sg offset. The caller must know that it is legal to call page_to_phys() | |
255 | * on the sg page. | |
256 | * | |
257 | **/ | |
85cdffcd | 258 | static inline dma_addr_t sg_phys(struct scatterlist *sg) |
82f66fbe JA |
259 | { |
260 | return page_to_phys(sg_page(sg)) + sg->offset; | |
261 | } | |
262 | ||
263 | /** | |
264 | * sg_virt - Return virtual address of an sg entry | |
18dabf47 | 265 | * @sg: SG entry |
82f66fbe JA |
266 | * |
267 | * Description: | |
268 | * This calls page_address() on the page in this sg entry, and adds the | |
269 | * sg offset. The caller must know that the sg page has a valid virtual | |
270 | * mapping. | |
271 | * | |
272 | **/ | |
273 | static inline void *sg_virt(struct scatterlist *sg) | |
274 | { | |
275 | return page_address(sg_page(sg)) + sg->offset; | |
276 | } | |
277 | ||
f3851786 PB |
278 | /** |
279 | * sg_init_marker - Initialize markers in sg table | |
280 | * @sgl: The SG table | |
281 | * @nents: Number of entries in table | |
282 | * | |
283 | **/ | |
284 | static inline void sg_init_marker(struct scatterlist *sgl, | |
285 | unsigned int nents) | |
286 | { | |
f3851786 PB |
287 | sg_mark_end(&sgl[nents - 1]); |
288 | } | |
289 | ||
2e484610 | 290 | int sg_nents(struct scatterlist *sg); |
cfaed10d | 291 | int sg_nents_for_len(struct scatterlist *sg, u64 len); |
0db9299f JA |
292 | struct scatterlist *sg_next(struct scatterlist *); |
293 | struct scatterlist *sg_last(struct scatterlist *s, unsigned int); | |
294 | void sg_init_table(struct scatterlist *, unsigned int); | |
295 | void sg_init_one(struct scatterlist *, const void *, unsigned int); | |
f8bcbe62 RJ |
296 | int sg_split(struct scatterlist *in, const int in_mapped_nents, |
297 | const off_t skip, const int nb_splits, | |
298 | const size_t *split_sizes, | |
299 | struct scatterlist **out, int *out_mapped_nents, | |
300 | gfp_t gfp_mask); | |
0db9299f JA |
301 | |
302 | typedef struct scatterlist *(sg_alloc_fn)(unsigned int, gfp_t); | |
303 | typedef void (sg_free_fn)(struct scatterlist *, unsigned int); | |
304 | ||
4635873c | 305 | void __sg_free_table(struct sg_table *, unsigned int, unsigned int, |
3e302dbc | 306 | sg_free_fn *, unsigned int); |
0db9299f | 307 | void sg_free_table(struct sg_table *); |
3e302dbc | 308 | void sg_free_append_table(struct sg_append_table *sgt); |
c53c6d6a | 309 | int __sg_alloc_table(struct sg_table *, unsigned int, unsigned int, |
4635873c | 310 | struct scatterlist *, unsigned int, gfp_t, sg_alloc_fn *); |
0db9299f | 311 | int sg_alloc_table(struct sg_table *, unsigned int, gfp_t); |
3e302dbc MG |
312 | int sg_alloc_append_table_from_pages(struct sg_append_table *sgt, |
313 | struct page **pages, unsigned int n_pages, | |
314 | unsigned int offset, unsigned long size, | |
315 | unsigned int max_segment, | |
316 | unsigned int left_pages, gfp_t gfp_mask); | |
90e7a6de MG |
317 | int sg_alloc_table_from_pages_segment(struct sg_table *sgt, struct page **pages, |
318 | unsigned int n_pages, unsigned int offset, | |
319 | unsigned long size, | |
320 | unsigned int max_segment, gfp_t gfp_mask); | |
321 | ||
322 | /** | |
323 | * sg_alloc_table_from_pages - Allocate and initialize an sg table from | |
324 | * an array of pages | |
325 | * @sgt: The sg table header to use | |
326 | * @pages: Pointer to an array of page pointers | |
327 | * @n_pages: Number of pages in the pages array | |
328 | * @offset: Offset from start of the first page to the start of a buffer | |
329 | * @size: Number of valid bytes in the buffer (after offset) | |
330 | * @gfp_mask: GFP allocation mask | |
331 | * | |
332 | * Description: | |
333 | * Allocate and initialize an sg table from a list of pages. Contiguous | |
334 | * ranges of the pages are squashed into a single scatterlist node. A user | |
335 | * may provide an offset at a start and a size of valid data in a buffer | |
336 | * specified by the page array. The returned sg table is released by | |
337 | * sg_free_table. | |
338 | * | |
339 | * Returns: | |
340 | * 0 on success, negative error on failure | |
341 | */ | |
342 | static inline int sg_alloc_table_from_pages(struct sg_table *sgt, | |
343 | struct page **pages, | |
344 | unsigned int n_pages, | |
345 | unsigned int offset, | |
346 | unsigned long size, gfp_t gfp_mask) | |
347 | { | |
348 | return sg_alloc_table_from_pages_segment(sgt, pages, n_pages, offset, | |
349 | size, UINT_MAX, gfp_mask); | |
350 | } | |
0db9299f | 351 | |
e80a0af4 BVA |
352 | #ifdef CONFIG_SGL_ALLOC |
353 | struct scatterlist *sgl_alloc_order(unsigned long long length, | |
354 | unsigned int order, bool chainable, | |
355 | gfp_t gfp, unsigned int *nent_p); | |
356 | struct scatterlist *sgl_alloc(unsigned long long length, gfp_t gfp, | |
357 | unsigned int *nent_p); | |
8c7a8d1c | 358 | void sgl_free_n_order(struct scatterlist *sgl, int nents, int order); |
e80a0af4 BVA |
359 | void sgl_free_order(struct scatterlist *sgl, int order); |
360 | void sgl_free(struct scatterlist *sgl); | |
361 | #endif /* CONFIG_SGL_ALLOC */ | |
362 | ||
386ecb12 DG |
363 | size_t sg_copy_buffer(struct scatterlist *sgl, unsigned int nents, void *buf, |
364 | size_t buflen, off_t skip, bool to_buffer); | |
365 | ||
b1adaf65 | 366 | size_t sg_copy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
2a1bf8f9 | 367 | const void *buf, size_t buflen); |
b1adaf65 FT |
368 | size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
369 | void *buf, size_t buflen); | |
370 | ||
df642cea | 371 | size_t sg_pcopy_from_buffer(struct scatterlist *sgl, unsigned int nents, |
2a1bf8f9 | 372 | const void *buf, size_t buflen, off_t skip); |
df642cea AM |
373 | size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents, |
374 | void *buf, size_t buflen, off_t skip); | |
0945e569 JT |
375 | size_t sg_zero_buffer(struct scatterlist *sgl, unsigned int nents, |
376 | size_t buflen, off_t skip); | |
df642cea | 377 | |
0db9299f JA |
378 | /* |
379 | * Maximum number of entries that will be allocated in one piece, if | |
380 | * a list larger than this is required then chaining will be utilized. | |
381 | */ | |
382 | #define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist)) | |
383 | ||
9b1d6c89 ML |
384 | /* |
385 | * The maximum number of SG segments that we will put inside a | |
386 | * scatterlist (unless chaining is used). Should ideally fit inside a | |
387 | * single page, to avoid a higher order allocation. We could define this | |
388 | * to SG_MAX_SINGLE_ALLOC to pack correctly at the highest order. The | |
389 | * minimum value is 32 | |
390 | */ | |
391 | #define SG_CHUNK_SIZE 128 | |
392 | ||
393 | /* | |
394 | * Like SG_CHUNK_SIZE, but for archs that have sg chaining. This limit | |
395 | * is totally arbitrary, a setting of 2048 will get you at least 8mb ios. | |
396 | */ | |
7c703e54 | 397 | #ifdef CONFIG_ARCH_NO_SG_CHAIN |
9b1d6c89 | 398 | #define SG_MAX_SEGMENTS SG_CHUNK_SIZE |
7c703e54 CH |
399 | #else |
400 | #define SG_MAX_SEGMENTS 2048 | |
9b1d6c89 ML |
401 | #endif |
402 | ||
403 | #ifdef CONFIG_SG_POOL | |
4635873c ML |
404 | void sg_free_table_chained(struct sg_table *table, |
405 | unsigned nents_first_chunk); | |
9b1d6c89 | 406 | int sg_alloc_table_chained(struct sg_table *table, int nents, |
4635873c ML |
407 | struct scatterlist *first_chunk, |
408 | unsigned nents_first_chunk); | |
9b1d6c89 ML |
409 | #endif |
410 | ||
a321e91b ID |
411 | /* |
412 | * sg page iterator | |
413 | * | |
d901b276 | 414 | * Iterates over sg entries page-by-page. On each successful iteration, you |
d2c4ada1 GP |
415 | * can call sg_page_iter_page(@piter) to get the current page. |
416 | * @piter->sg will point to the sg holding this page and @piter->sg_pgoffset to | |
417 | * the page's page offset within the sg. The iteration will stop either when a | |
418 | * maximum number of sg entries was reached or a terminating sg | |
419 | * (sg_last(sg) == true) was reached. | |
a321e91b ID |
420 | */ |
421 | struct sg_page_iter { | |
a321e91b ID |
422 | struct scatterlist *sg; /* sg holding the page */ |
423 | unsigned int sg_pgoffset; /* page offset within the sg */ | |
424 | ||
425 | /* these are internal states, keep away */ | |
426 | unsigned int __nents; /* remaining sg entries */ | |
427 | int __pg_advance; /* nr pages to advance at the | |
428 | * next step */ | |
429 | }; | |
430 | ||
d901b276 JG |
431 | /* |
432 | * sg page iterator for DMA addresses | |
433 | * | |
434 | * This is the same as sg_page_iter however you can call | |
435 | * sg_page_iter_dma_address(@dma_iter) to get the page's DMA | |
436 | * address. sg_page_iter_page() cannot be called on this iterator. | |
437 | */ | |
438 | struct sg_dma_page_iter { | |
439 | struct sg_page_iter base; | |
440 | }; | |
441 | ||
a321e91b | 442 | bool __sg_page_iter_next(struct sg_page_iter *piter); |
d901b276 | 443 | bool __sg_page_iter_dma_next(struct sg_dma_page_iter *dma_iter); |
a321e91b ID |
444 | void __sg_page_iter_start(struct sg_page_iter *piter, |
445 | struct scatterlist *sglist, unsigned int nents, | |
446 | unsigned long pgoffset); | |
2db76d7c ID |
447 | /** |
448 | * sg_page_iter_page - get the current page held by the page iterator | |
449 | * @piter: page iterator holding the page | |
450 | */ | |
451 | static inline struct page *sg_page_iter_page(struct sg_page_iter *piter) | |
452 | { | |
453 | return nth_page(sg_page(piter->sg), piter->sg_pgoffset); | |
454 | } | |
455 | ||
456 | /** | |
457 | * sg_page_iter_dma_address - get the dma address of the current page held by | |
458 | * the page iterator. | |
d901b276 | 459 | * @dma_iter: page iterator holding the page |
2db76d7c | 460 | */ |
d901b276 JG |
461 | static inline dma_addr_t |
462 | sg_page_iter_dma_address(struct sg_dma_page_iter *dma_iter) | |
2db76d7c | 463 | { |
d901b276 JG |
464 | return sg_dma_address(dma_iter->base.sg) + |
465 | (dma_iter->base.sg_pgoffset << PAGE_SHIFT); | |
2db76d7c | 466 | } |
a321e91b ID |
467 | |
468 | /** | |
469 | * for_each_sg_page - iterate over the pages of the given sg list | |
470 | * @sglist: sglist to iterate over | |
471 | * @piter: page iterator to hold current page, sg, sg_pgoffset | |
472 | * @nents: maximum number of sg entries to iterate over | |
709d6d73 | 473 | * @pgoffset: starting page offset (in pages) |
d901b276 JG |
474 | * |
475 | * Callers may use sg_page_iter_page() to get each page pointer. | |
709d6d73 | 476 | * In each loop it operates on PAGE_SIZE unit. |
a321e91b ID |
477 | */ |
478 | #define for_each_sg_page(sglist, piter, nents, pgoffset) \ | |
479 | for (__sg_page_iter_start((piter), (sglist), (nents), (pgoffset)); \ | |
480 | __sg_page_iter_next(piter);) | |
137d3edb | 481 | |
d901b276 JG |
482 | /** |
483 | * for_each_sg_dma_page - iterate over the pages of the given sg list | |
484 | * @sglist: sglist to iterate over | |
709d6d73 | 485 | * @dma_iter: DMA page iterator to hold current page |
d901b276 JG |
486 | * @dma_nents: maximum number of sg entries to iterate over, this is the value |
487 | * returned from dma_map_sg | |
709d6d73 | 488 | * @pgoffset: starting page offset (in pages) |
d901b276 JG |
489 | * |
490 | * Callers may use sg_page_iter_dma_address() to get each page's DMA address. | |
709d6d73 | 491 | * In each loop it operates on PAGE_SIZE unit. |
d901b276 JG |
492 | */ |
493 | #define for_each_sg_dma_page(sglist, dma_iter, dma_nents, pgoffset) \ | |
494 | for (__sg_page_iter_start(&(dma_iter)->base, sglist, dma_nents, \ | |
495 | pgoffset); \ | |
496 | __sg_page_iter_dma_next(dma_iter);) | |
497 | ||
709d6d73 MS |
498 | /** |
499 | * for_each_sgtable_page - iterate over all pages in the sg_table object | |
500 | * @sgt: sg_table object to iterate over | |
501 | * @piter: page iterator to hold current page | |
502 | * @pgoffset: starting page offset (in pages) | |
503 | * | |
504 | * Iterates over the all memory pages in the buffer described by | |
505 | * a scatterlist stored in the given sg_table object. | |
506 | * See also for_each_sg_page(). In each loop it operates on PAGE_SIZE unit. | |
507 | */ | |
508 | #define for_each_sgtable_page(sgt, piter, pgoffset) \ | |
68d23705 | 509 | for_each_sg_page((sgt)->sgl, piter, (sgt)->orig_nents, pgoffset) |
709d6d73 MS |
510 | |
511 | /** | |
512 | * for_each_sgtable_dma_page - iterate over the DMA mapped sg_table object | |
513 | * @sgt: sg_table object to iterate over | |
514 | * @dma_iter: DMA page iterator to hold current page | |
515 | * @pgoffset: starting page offset (in pages) | |
516 | * | |
517 | * Iterates over the all DMA mapped pages in the buffer described by | |
518 | * a scatterlist stored in the given sg_table object. | |
519 | * See also for_each_sg_dma_page(). In each loop it operates on PAGE_SIZE | |
520 | * unit. | |
521 | */ | |
522 | #define for_each_sgtable_dma_page(sgt, dma_iter, pgoffset) \ | |
68d23705 | 523 | for_each_sg_dma_page((sgt)->sgl, dma_iter, (sgt)->nents, pgoffset) |
709d6d73 MS |
524 | |
525 | ||
137d3edb TH |
526 | /* |
527 | * Mapping sg iterator | |
528 | * | |
529 | * Iterates over sg entries mapping page-by-page. On each successful | |
530 | * iteration, @miter->page points to the mapped page and | |
531 | * @miter->length bytes of data can be accessed at @miter->addr. As | |
c23c8082 | 532 | * long as an iteration is enclosed between start and stop, the user |
137d3edb TH |
533 | * is free to choose control structure and when to stop. |
534 | * | |
535 | * @miter->consumed is set to @miter->length on each iteration. It | |
536 | * can be adjusted if the user can't consume all the bytes in one go. | |
537 | * Also, a stopped iteration can be resumed by calling next on it. | |
538 | * This is useful when iteration needs to release all resources and | |
539 | * continue later (e.g. at the next interrupt). | |
540 | */ | |
541 | ||
542 | #define SG_MITER_ATOMIC (1 << 0) /* use kmap_atomic */ | |
6de7e356 SAS |
543 | #define SG_MITER_TO_SG (1 << 1) /* flush back to phys on unmap */ |
544 | #define SG_MITER_FROM_SG (1 << 2) /* nop */ | |
137d3edb TH |
545 | |
546 | struct sg_mapping_iter { | |
547 | /* the following three fields can be accessed directly */ | |
548 | struct page *page; /* currently mapped page */ | |
549 | void *addr; /* pointer to the mapped area */ | |
550 | size_t length; /* length of the mapped area */ | |
551 | size_t consumed; /* number of consumed bytes */ | |
4225fc85 | 552 | struct sg_page_iter piter; /* page iterator */ |
137d3edb TH |
553 | |
554 | /* these are internal states, keep away */ | |
4225fc85 ID |
555 | unsigned int __offset; /* offset within page */ |
556 | unsigned int __remaining; /* remaining bytes on page */ | |
137d3edb TH |
557 | unsigned int __flags; |
558 | }; | |
559 | ||
560 | void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl, | |
561 | unsigned int nents, unsigned int flags); | |
0d6077f8 | 562 | bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset); |
137d3edb TH |
563 | bool sg_miter_next(struct sg_mapping_iter *miter); |
564 | void sg_miter_stop(struct sg_mapping_iter *miter); | |
565 | ||
1da177e4 | 566 | #endif /* _LINUX_SCATTERLIST_H */ |