Commit | Line | Data |
---|---|---|
e184e2be | 1 | // SPDX-License-Identifier: GPL-2.0+ |
ea082fb1 HS |
2 | /* |
3 | * comedi_buf.c | |
4 | * | |
5 | * COMEDI - Linux Control and Measurement Device Interface | |
6 | * Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org> | |
b8d57655 | 7 | * Copyright (C) 2002 Frank Mori Hess <fmhess@users.sourceforge.net> |
ea082fb1 HS |
8 | */ |
9 | ||
76a1de32 | 10 | #include <linux/vmalloc.h> |
af93da31 | 11 | #include <linux/slab.h> |
df0e68c1 | 12 | #include <linux/comedi/comedidev.h> |
ea082fb1 HS |
13 | #include "comedi_internal.h" |
14 | ||
6bd76457 HS |
15 | #ifdef PAGE_KERNEL_NOCACHE |
16 | #define COMEDI_PAGE_PROTECTION PAGE_KERNEL_NOCACHE | |
17 | #else | |
18 | #define COMEDI_PAGE_PROTECTION PAGE_KERNEL | |
19 | #endif | |
20 | ||
af93da31 | 21 | static void comedi_buf_map_kref_release(struct kref *kref) |
718c4d68 | 22 | { |
af93da31 IA |
23 | struct comedi_buf_map *bm = |
24 | container_of(kref, struct comedi_buf_map, refcount); | |
718c4d68 | 25 | struct comedi_buf_page *buf; |
af93da31 | 26 | unsigned int i; |
718c4d68 | 27 | |
af93da31 | 28 | if (bm->page_list) { |
e3647214 IA |
29 | if (bm->dma_dir != DMA_NONE) { |
30 | /* | |
31 | * DMA buffer was allocated as a single block. | |
32 | * Address is in page_list[0]. | |
33 | */ | |
34 | buf = &bm->page_list[0]; | |
35 | dma_free_coherent(bm->dma_hw_dev, | |
36 | PAGE_SIZE * bm->n_pages, | |
37 | buf->virt_addr, buf->dma_addr); | |
38 | } else { | |
39 | for (i = 0; i < bm->n_pages; i++) { | |
40 | buf = &bm->page_list[i]; | |
41 | ClearPageReserved(virt_to_page(buf->virt_addr)); | |
718c4d68 HS |
42 | free_page((unsigned long)buf->virt_addr); |
43 | } | |
44 | } | |
af93da31 IA |
45 | vfree(bm->page_list); |
46 | } | |
47 | if (bm->dma_dir != DMA_NONE) | |
48 | put_device(bm->dma_hw_dev); | |
49 | kfree(bm); | |
50 | } | |
51 | ||
52 | static void __comedi_buf_free(struct comedi_device *dev, | |
53 | struct comedi_subdevice *s) | |
54 | { | |
55 | struct comedi_async *async = s->async; | |
b34aa86f IA |
56 | struct comedi_buf_map *bm; |
57 | unsigned long flags; | |
af93da31 IA |
58 | |
59 | if (async->prealloc_buf) { | |
e3647214 IA |
60 | if (s->async_dma_dir == DMA_NONE) |
61 | vunmap(async->prealloc_buf); | |
af93da31 IA |
62 | async->prealloc_buf = NULL; |
63 | async->prealloc_bufsz = 0; | |
718c4d68 | 64 | } |
af93da31 | 65 | |
b34aa86f IA |
66 | spin_lock_irqsave(&s->spin_lock, flags); |
67 | bm = async->buf_map; | |
af93da31 | 68 | async->buf_map = NULL; |
b34aa86f IA |
69 | spin_unlock_irqrestore(&s->spin_lock, flags); |
70 | comedi_buf_map_put(bm); | |
718c4d68 HS |
71 | } |
72 | ||
e3647214 IA |
73 | static struct comedi_buf_map * |
74 | comedi_buf_map_alloc(struct comedi_device *dev, enum dma_data_direction dma_dir, | |
75 | unsigned int n_pages) | |
76 | { | |
77 | struct comedi_buf_map *bm; | |
78 | struct comedi_buf_page *buf; | |
79 | unsigned int i; | |
80 | ||
81 | bm = kzalloc(sizeof(*bm), GFP_KERNEL); | |
82 | if (!bm) | |
83 | return NULL; | |
84 | ||
85 | kref_init(&bm->refcount); | |
86 | bm->dma_dir = dma_dir; | |
87 | if (bm->dma_dir != DMA_NONE) { | |
88 | /* Need ref to hardware device to free buffer later. */ | |
89 | bm->dma_hw_dev = get_device(dev->hw_dev); | |
90 | } | |
91 | ||
92 | bm->page_list = vzalloc(sizeof(*buf) * n_pages); | |
93 | if (!bm->page_list) | |
94 | goto err; | |
95 | ||
96 | if (bm->dma_dir != DMA_NONE) { | |
97 | void *virt_addr; | |
98 | dma_addr_t dma_addr; | |
99 | ||
100 | /* | |
101 | * Currently, the DMA buffer needs to be allocated as a | |
102 | * single block so that it can be mmap()'ed. | |
103 | */ | |
104 | virt_addr = dma_alloc_coherent(bm->dma_hw_dev, | |
105 | PAGE_SIZE * n_pages, &dma_addr, | |
106 | GFP_KERNEL); | |
107 | if (!virt_addr) | |
108 | goto err; | |
109 | ||
110 | for (i = 0; i < n_pages; i++) { | |
111 | buf = &bm->page_list[i]; | |
112 | buf->virt_addr = virt_addr + (i << PAGE_SHIFT); | |
113 | buf->dma_addr = dma_addr + (i << PAGE_SHIFT); | |
114 | } | |
115 | ||
116 | bm->n_pages = i; | |
117 | } else { | |
118 | for (i = 0; i < n_pages; i++) { | |
119 | buf = &bm->page_list[i]; | |
120 | buf->virt_addr = (void *)get_zeroed_page(GFP_KERNEL); | |
121 | if (!buf->virt_addr) | |
122 | break; | |
123 | ||
124 | SetPageReserved(virt_to_page(buf->virt_addr)); | |
125 | } | |
126 | ||
127 | bm->n_pages = i; | |
128 | if (i < n_pages) | |
129 | goto err; | |
130 | } | |
131 | ||
132 | return bm; | |
133 | ||
134 | err: | |
135 | comedi_buf_map_put(bm); | |
136 | return NULL; | |
137 | } | |
138 | ||
6bd76457 HS |
139 | static void __comedi_buf_alloc(struct comedi_device *dev, |
140 | struct comedi_subdevice *s, | |
938cae7a | 141 | unsigned int n_pages) |
6bd76457 HS |
142 | { |
143 | struct comedi_async *async = s->async; | |
144 | struct page **pages = NULL; | |
af93da31 | 145 | struct comedi_buf_map *bm; |
6bd76457 | 146 | struct comedi_buf_page *buf; |
b34aa86f | 147 | unsigned long flags; |
938cae7a | 148 | unsigned int i; |
6bd76457 | 149 | |
e9166139 IA |
150 | if (!IS_ENABLED(CONFIG_HAS_DMA) && s->async_dma_dir != DMA_NONE) { |
151 | dev_err(dev->class_dev, | |
152 | "dma buffer allocation not supported\n"); | |
153 | return; | |
154 | } | |
155 | ||
e3647214 | 156 | bm = comedi_buf_map_alloc(dev, s->async_dma_dir, n_pages); |
af93da31 IA |
157 | if (!bm) |
158 | return; | |
159 | ||
b34aa86f IA |
160 | spin_lock_irqsave(&s->spin_lock, flags); |
161 | async->buf_map = bm; | |
162 | spin_unlock_irqrestore(&s->spin_lock, flags); | |
af93da31 | 163 | |
e3647214 IA |
164 | if (bm->dma_dir != DMA_NONE) { |
165 | /* | |
166 | * DMA buffer was allocated as a single block. | |
167 | * Address is in page_list[0]. | |
168 | */ | |
169 | buf = &bm->page_list[0]; | |
170 | async->prealloc_buf = buf->virt_addr; | |
171 | } else { | |
6bd76457 | 172 | pages = vmalloc(sizeof(struct page *) * n_pages); |
e3647214 IA |
173 | if (!pages) |
174 | return; | |
6bd76457 | 175 | |
e3647214 IA |
176 | for (i = 0; i < n_pages; i++) { |
177 | buf = &bm->page_list[i]; | |
178 | pages[i] = virt_to_page(buf->virt_addr); | |
179 | } | |
6bd76457 | 180 | |
e3647214 | 181 | /* vmap the pages to prealloc_buf */ |
6bd76457 HS |
182 | async->prealloc_buf = vmap(pages, n_pages, VM_MAP, |
183 | COMEDI_PAGE_PROTECTION); | |
184 | ||
e3647214 IA |
185 | vfree(pages); |
186 | } | |
6bd76457 HS |
187 | } |
188 | ||
af93da31 IA |
189 | void comedi_buf_map_get(struct comedi_buf_map *bm) |
190 | { | |
191 | if (bm) | |
192 | kref_get(&bm->refcount); | |
193 | } | |
194 | ||
195 | int comedi_buf_map_put(struct comedi_buf_map *bm) | |
196 | { | |
197 | if (bm) | |
198 | return kref_put(&bm->refcount, comedi_buf_map_kref_release); | |
199 | return 1; | |
200 | } | |
201 | ||
255364f7 IA |
202 | /* helper for "access" vm operation */ |
203 | int comedi_buf_map_access(struct comedi_buf_map *bm, unsigned long offset, | |
204 | void *buf, int len, int write) | |
205 | { | |
f47d8b11 | 206 | unsigned int pgoff = offset_in_page(offset); |
255364f7 IA |
207 | unsigned long pg = offset >> PAGE_SHIFT; |
208 | int done = 0; | |
209 | ||
210 | while (done < len && pg < bm->n_pages) { | |
211 | int l = min_t(int, len - done, PAGE_SIZE - pgoff); | |
212 | void *b = bm->page_list[pg].virt_addr + pgoff; | |
213 | ||
214 | if (write) | |
215 | memcpy(b, buf, l); | |
216 | else | |
217 | memcpy(buf, b, l); | |
218 | buf += l; | |
219 | done += l; | |
220 | pg++; | |
221 | pgoff = 0; | |
222 | } | |
223 | return done; | |
224 | } | |
225 | ||
b34aa86f IA |
226 | /* returns s->async->buf_map and increments its kref refcount */ |
227 | struct comedi_buf_map * | |
228 | comedi_buf_map_from_subdev_get(struct comedi_subdevice *s) | |
229 | { | |
230 | struct comedi_async *async = s->async; | |
231 | struct comedi_buf_map *bm = NULL; | |
232 | unsigned long flags; | |
233 | ||
234 | if (!async) | |
235 | return NULL; | |
236 | ||
237 | spin_lock_irqsave(&s->spin_lock, flags); | |
238 | bm = async->buf_map; | |
239 | /* only want it if buffer pages allocated */ | |
240 | if (bm && bm->n_pages) | |
241 | comedi_buf_map_get(bm); | |
242 | else | |
243 | bm = NULL; | |
244 | spin_unlock_irqrestore(&s->spin_lock, flags); | |
245 | ||
246 | return bm; | |
247 | } | |
248 | ||
d4526ab4 | 249 | bool comedi_buf_is_mmapped(struct comedi_subdevice *s) |
af93da31 | 250 | { |
d4526ab4 | 251 | struct comedi_buf_map *bm = s->async->buf_map; |
af93da31 | 252 | |
2c935bc5 | 253 | return bm && (kref_read(&bm->refcount) > 1); |
af93da31 IA |
254 | } |
255 | ||
ea082fb1 HS |
256 | int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s, |
257 | unsigned long new_size) | |
258 | { | |
259 | struct comedi_async *async = s->async; | |
260 | ||
77c21b62 IA |
261 | lockdep_assert_held(&dev->mutex); |
262 | ||
ea082fb1 HS |
263 | /* Round up new_size to multiple of PAGE_SIZE */ |
264 | new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK; | |
265 | ||
266 | /* if no change is required, do nothing */ | |
267 | if (async->prealloc_buf && async->prealloc_bufsz == new_size) | |
268 | return 0; | |
269 | ||
718c4d68 | 270 | /* deallocate old buffer */ |
af93da31 | 271 | __comedi_buf_free(dev, s); |
718c4d68 | 272 | |
6bd76457 | 273 | /* allocate new buffer */ |
ea082fb1 | 274 | if (new_size) { |
938cae7a | 275 | unsigned int n_pages = new_size >> PAGE_SHIFT; |
6bd76457 HS |
276 | |
277 | __comedi_buf_alloc(dev, s, n_pages); | |
ea082fb1 | 278 | |
718c4d68 | 279 | if (!async->prealloc_buf) { |
6bd76457 | 280 | /* allocation failed */ |
af93da31 | 281 | __comedi_buf_free(dev, s); |
ea082fb1 HS |
282 | return -ENOMEM; |
283 | } | |
ea082fb1 HS |
284 | } |
285 | async->prealloc_bufsz = new_size; | |
286 | ||
287 | return 0; | |
288 | } | |
289 | ||
fcc18a9a | 290 | void comedi_buf_reset(struct comedi_subdevice *s) |
ea082fb1 | 291 | { |
fcc18a9a IA |
292 | struct comedi_async *async = s->async; |
293 | ||
ea082fb1 HS |
294 | async->buf_write_alloc_count = 0; |
295 | async->buf_write_count = 0; | |
296 | async->buf_read_alloc_count = 0; | |
297 | async->buf_read_count = 0; | |
298 | ||
299 | async->buf_write_ptr = 0; | |
300 | async->buf_read_ptr = 0; | |
301 | ||
302 | async->cur_chan = 0; | |
1dacbe5b | 303 | async->scans_done = 0; |
ea082fb1 HS |
304 | async->scan_progress = 0; |
305 | async->munge_chan = 0; | |
306 | async->munge_count = 0; | |
307 | async->munge_ptr = 0; | |
308 | ||
309 | async->events = 0; | |
310 | } | |
311 | ||
274ec5ee | 312 | static unsigned int comedi_buf_write_n_unalloc(struct comedi_subdevice *s) |
ea082fb1 | 313 | { |
a1c0e5fe | 314 | struct comedi_async *async = s->async; |
f8f76e90 | 315 | unsigned int free_end = async->buf_read_count + async->prealloc_bufsz; |
ea082fb1 | 316 | |
f8f76e90 HS |
317 | return free_end - async->buf_write_alloc_count; |
318 | } | |
319 | ||
432fbde7 IA |
320 | unsigned int comedi_buf_write_n_available(struct comedi_subdevice *s) |
321 | { | |
322 | struct comedi_async *async = s->async; | |
323 | unsigned int free_end = async->buf_read_count + async->prealloc_bufsz; | |
324 | ||
325 | return free_end - async->buf_write_count; | |
326 | } | |
327 | ||
c240e20c IA |
328 | /** |
329 | * comedi_buf_write_alloc() - Reserve buffer space for writing | |
330 | * @s: COMEDI subdevice. | |
331 | * @nbytes: Maximum space to reserve in bytes. | |
332 | * | |
333 | * Reserve up to @nbytes bytes of space to be written in the COMEDI acquisition | |
334 | * data buffer associated with the subdevice. The amount reserved is limited | |
335 | * by the space available. | |
336 | * | |
337 | * Return: The amount of space reserved in bytes. | |
338 | */ | |
0cf5efaa HS |
339 | unsigned int comedi_buf_write_alloc(struct comedi_subdevice *s, |
340 | unsigned int nbytes) | |
f8f76e90 | 341 | { |
8ab4fe7e | 342 | struct comedi_async *async = s->async; |
274ec5ee | 343 | unsigned int unalloc = comedi_buf_write_n_unalloc(s); |
f8f76e90 | 344 | |
274ec5ee IA |
345 | if (nbytes > unalloc) |
346 | nbytes = unalloc; | |
ea082fb1 | 347 | |
f8f76e90 HS |
348 | async->buf_write_alloc_count += nbytes; |
349 | ||
350 | /* | |
351 | * ensure the async buffer 'counts' are read and updated | |
352 | * before we write data to the write-alloc'ed buffer space | |
ea082fb1 HS |
353 | */ |
354 | smp_mb(); | |
f8f76e90 | 355 | |
ea082fb1 HS |
356 | return nbytes; |
357 | } | |
5660e742 | 358 | EXPORT_SYMBOL_GPL(comedi_buf_write_alloc); |
ea082fb1 | 359 | |
8d4be669 HS |
360 | /* |
361 | * munging is applied to data by core as it passes between user | |
362 | * and kernel space | |
363 | */ | |
5b108588 | 364 | static unsigned int comedi_buf_munge(struct comedi_subdevice *s, |
ea082fb1 HS |
365 | unsigned int num_bytes) |
366 | { | |
5b108588 | 367 | struct comedi_async *async = s->async; |
ea082fb1 | 368 | unsigned int count = 0; |
938cae7a | 369 | const unsigned int num_sample_bytes = comedi_bytes_per_sample(s); |
ea082fb1 | 370 | |
8d4be669 | 371 | if (!s->munge || (async->cmd.flags & CMDF_RAWDATA)) { |
ea082fb1 | 372 | async->munge_count += num_bytes; |
d70fb897 SK |
373 | return num_bytes; |
374 | } | |
8d4be669 | 375 | |
d70fb897 SK |
376 | /* don't munge partial samples */ |
377 | num_bytes -= num_bytes % num_sample_bytes; | |
378 | while (count < num_bytes) { | |
379 | int block_size = num_bytes - count; | |
380 | unsigned int buf_end; | |
8d4be669 | 381 | |
d70fb897 SK |
382 | buf_end = async->prealloc_bufsz - async->munge_ptr; |
383 | if (block_size > buf_end) | |
384 | block_size = buf_end; | |
8d4be669 | 385 | |
d70fb897 SK |
386 | s->munge(s->device, s, |
387 | async->prealloc_buf + async->munge_ptr, | |
388 | block_size, async->munge_chan); | |
389 | ||
390 | /* | |
391 | * ensure data is munged in buffer before the | |
392 | * async buffer munge_count is incremented | |
393 | */ | |
394 | smp_wmb(); | |
395 | ||
396 | async->munge_chan += block_size / num_sample_bytes; | |
397 | async->munge_chan %= async->cmd.chanlist_len; | |
398 | async->munge_count += block_size; | |
399 | async->munge_ptr += block_size; | |
400 | async->munge_ptr %= async->prealloc_bufsz; | |
401 | count += block_size; | |
ea082fb1 | 402 | } |
8d4be669 | 403 | |
ea082fb1 HS |
404 | return count; |
405 | } | |
406 | ||
0f1f34e8 | 407 | unsigned int comedi_buf_write_n_allocated(struct comedi_subdevice *s) |
8bd650f9 | 408 | { |
0f1f34e8 IA |
409 | struct comedi_async *async = s->async; |
410 | ||
8bd650f9 HS |
411 | return async->buf_write_alloc_count - async->buf_write_count; |
412 | } | |
413 | ||
c240e20c IA |
414 | /** |
415 | * comedi_buf_write_free() - Free buffer space after it is written | |
416 | * @s: COMEDI subdevice. | |
417 | * @nbytes: Maximum space to free in bytes. | |
418 | * | |
419 | * Free up to @nbytes bytes of space previously reserved for writing in the | |
420 | * COMEDI acquisition data buffer associated with the subdevice. The amount of | |
421 | * space freed is limited to the amount that was reserved. The freed space is | |
422 | * assumed to have been filled with sample data by the writer. | |
423 | * | |
424 | * If the samples in the freed space need to be "munged", do so here. The | |
425 | * freed space becomes available for allocation by the reader. | |
426 | * | |
427 | * Return: The amount of space freed in bytes. | |
428 | */ | |
940dd35d | 429 | unsigned int comedi_buf_write_free(struct comedi_subdevice *s, |
8ae560a1 | 430 | unsigned int nbytes) |
ea082fb1 | 431 | { |
940dd35d | 432 | struct comedi_async *async = s->async; |
0f1f34e8 | 433 | unsigned int allocated = comedi_buf_write_n_allocated(s); |
d21af4cb | 434 | |
6166ce87 | 435 | if (nbytes > allocated) |
d21af4cb | 436 | nbytes = allocated; |
6166ce87 | 437 | |
ea082fb1 HS |
438 | async->buf_write_count += nbytes; |
439 | async->buf_write_ptr += nbytes; | |
5b108588 | 440 | comedi_buf_munge(s, async->buf_write_count - async->munge_count); |
ea082fb1 HS |
441 | if (async->buf_write_ptr >= async->prealloc_bufsz) |
442 | async->buf_write_ptr %= async->prealloc_bufsz; | |
443 | ||
444 | return nbytes; | |
445 | } | |
5660e742 | 446 | EXPORT_SYMBOL_GPL(comedi_buf_write_free); |
ea082fb1 | 447 | |
c240e20c IA |
448 | /** |
449 | * comedi_buf_read_n_available() - Determine amount of readable buffer space | |
450 | * @s: COMEDI subdevice. | |
451 | * | |
452 | * Determine the amount of readable buffer space in the COMEDI acquisition data | |
453 | * buffer associated with the subdevice. The readable buffer space is that | |
454 | * which has been freed by the writer and "munged" to the sample data format | |
455 | * expected by COMEDI if necessary. | |
456 | * | |
457 | * Return: The amount of readable buffer space. | |
458 | */ | |
e9edef3a | 459 | unsigned int comedi_buf_read_n_available(struct comedi_subdevice *s) |
ea082fb1 | 460 | { |
e9edef3a | 461 | struct comedi_async *async = s->async; |
938cae7a | 462 | unsigned int num_bytes; |
ea082fb1 | 463 | |
43f9137d | 464 | if (!async) |
ea082fb1 | 465 | return 0; |
43f9137d | 466 | |
ea082fb1 | 467 | num_bytes = async->munge_count - async->buf_read_count; |
43f9137d HS |
468 | |
469 | /* | |
470 | * ensure the async buffer 'counts' are read before we | |
471 | * attempt to read data from the buffer | |
ea082fb1 HS |
472 | */ |
473 | smp_rmb(); | |
43f9137d | 474 | |
ea082fb1 HS |
475 | return num_bytes; |
476 | } | |
5660e742 | 477 | EXPORT_SYMBOL_GPL(comedi_buf_read_n_available); |
ea082fb1 | 478 | |
c240e20c IA |
479 | /** |
480 | * comedi_buf_read_alloc() - Reserve buffer space for reading | |
481 | * @s: COMEDI subdevice. | |
482 | * @nbytes: Maximum space to reserve in bytes. | |
483 | * | |
484 | * Reserve up to @nbytes bytes of previously written and "munged" buffer space | |
485 | * for reading in the COMEDI acquisition data buffer associated with the | |
486 | * subdevice. The amount reserved is limited to the space available. The | |
487 | * reader can read from the reserved space and then free it. A reader is also | |
488 | * allowed to read from the space before reserving it as long as it determines | |
489 | * the amount of readable data available, but the space needs to be marked as | |
490 | * reserved before it can be freed. | |
491 | * | |
492 | * Return: The amount of space reserved in bytes. | |
493 | */ | |
d13be55a | 494 | unsigned int comedi_buf_read_alloc(struct comedi_subdevice *s, |
8ae560a1 | 495 | unsigned int nbytes) |
ea082fb1 | 496 | { |
d13be55a | 497 | struct comedi_async *async = s->async; |
034cbd17 HS |
498 | unsigned int available; |
499 | ||
500 | available = async->munge_count - async->buf_read_alloc_count; | |
501 | if (nbytes > available) | |
502 | nbytes = available; | |
503 | ||
ea082fb1 | 504 | async->buf_read_alloc_count += nbytes; |
034cbd17 HS |
505 | |
506 | /* | |
507 | * ensure the async buffer 'counts' are read before we | |
508 | * attempt to read data from the read-alloc'ed buffer space | |
509 | */ | |
ea082fb1 | 510 | smp_rmb(); |
034cbd17 | 511 | |
ea082fb1 HS |
512 | return nbytes; |
513 | } | |
5660e742 | 514 | EXPORT_SYMBOL_GPL(comedi_buf_read_alloc); |
ea082fb1 | 515 | |
5b2b64b7 HS |
516 | static unsigned int comedi_buf_read_n_allocated(struct comedi_async *async) |
517 | { | |
518 | return async->buf_read_alloc_count - async->buf_read_count; | |
519 | } | |
520 | ||
c240e20c IA |
521 | /** |
522 | * comedi_buf_read_free() - Free buffer space after it has been read | |
523 | * @s: COMEDI subdevice. | |
524 | * @nbytes: Maximum space to free in bytes. | |
525 | * | |
526 | * Free up to @nbytes bytes of buffer space previously reserved for reading in | |
527 | * the COMEDI acquisition data buffer associated with the subdevice. The | |
528 | * amount of space freed is limited to the amount that was reserved. | |
529 | * | |
530 | * The freed space becomes available for allocation by the writer. | |
531 | * | |
532 | * Return: The amount of space freed in bytes. | |
533 | */ | |
f1df8662 | 534 | unsigned int comedi_buf_read_free(struct comedi_subdevice *s, |
8ae560a1 | 535 | unsigned int nbytes) |
ea082fb1 | 536 | { |
f1df8662 | 537 | struct comedi_async *async = s->async; |
3abfa106 HS |
538 | unsigned int allocated; |
539 | ||
540 | /* | |
541 | * ensure data has been read out of buffer before | |
542 | * the async read count is incremented | |
543 | */ | |
ea082fb1 | 544 | smp_mb(); |
3abfa106 HS |
545 | |
546 | allocated = comedi_buf_read_n_allocated(async); | |
215040e1 | 547 | if (nbytes > allocated) |
3abfa106 | 548 | nbytes = allocated; |
215040e1 | 549 | |
ea082fb1 HS |
550 | async->buf_read_count += nbytes; |
551 | async->buf_read_ptr += nbytes; | |
552 | async->buf_read_ptr %= async->prealloc_bufsz; | |
553 | return nbytes; | |
554 | } | |
5660e742 | 555 | EXPORT_SYMBOL_GPL(comedi_buf_read_free); |
ea082fb1 | 556 | |
aa26e46b | 557 | static void comedi_buf_memcpy_to(struct comedi_subdevice *s, |
aa26e46b | 558 | const void *data, unsigned int num_bytes) |
ea082fb1 | 559 | { |
00603a9c | 560 | struct comedi_async *async = s->async; |
319ad742 | 561 | unsigned int write_ptr = async->buf_write_ptr; |
ea082fb1 HS |
562 | |
563 | while (num_bytes) { | |
564 | unsigned int block_size; | |
565 | ||
566 | if (write_ptr + num_bytes > async->prealloc_bufsz) | |
567 | block_size = async->prealloc_bufsz - write_ptr; | |
568 | else | |
569 | block_size = num_bytes; | |
570 | ||
571 | memcpy(async->prealloc_buf + write_ptr, data, block_size); | |
572 | ||
573 | data += block_size; | |
574 | num_bytes -= block_size; | |
575 | ||
576 | write_ptr = 0; | |
577 | } | |
578 | } | |
ea082fb1 | 579 | |
9e2093d2 | 580 | static void comedi_buf_memcpy_from(struct comedi_subdevice *s, |
9e2093d2 | 581 | void *dest, unsigned int nbytes) |
ea082fb1 HS |
582 | { |
583 | void *src; | |
2fadffc0 | 584 | struct comedi_async *async = s->async; |
0ca7f61c | 585 | unsigned int read_ptr = async->buf_read_ptr; |
ea082fb1 HS |
586 | |
587 | while (nbytes) { | |
588 | unsigned int block_size; | |
589 | ||
590 | src = async->prealloc_buf + read_ptr; | |
591 | ||
592 | if (nbytes >= async->prealloc_bufsz - read_ptr) | |
593 | block_size = async->prealloc_bufsz - read_ptr; | |
594 | else | |
595 | block_size = nbytes; | |
596 | ||
597 | memcpy(dest, src, block_size); | |
598 | nbytes -= block_size; | |
599 | dest += block_size; | |
600 | read_ptr = 0; | |
601 | } | |
602 | } | |
ea29c1d5 | 603 | |
5438da85 | 604 | /** |
67ecc3dd IA |
605 | * comedi_buf_write_samples() - Write sample data to COMEDI buffer |
606 | * @s: COMEDI subdevice. | |
607 | * @data: Pointer to source samples. | |
608 | * @nsamples: Number of samples to write. | |
5438da85 | 609 | * |
67ecc3dd IA |
610 | * Write up to @nsamples samples to the COMEDI acquisition data buffer |
611 | * associated with the subdevice, mark it as written and update the | |
612 | * acquisition scan progress. If there is not enough room for the specified | |
613 | * number of samples, the number of samples written is limited to the number | |
614 | * that will fit and the %COMEDI_CB_OVERFLOW event flag is set to cause the | |
615 | * acquisition to terminate with an overrun error. Set the %COMEDI_CB_BLOCK | |
616 | * event flag if any samples are written to cause waiting tasks to be woken | |
617 | * when the event flags are processed. | |
5438da85 | 618 | * |
67ecc3dd | 619 | * Return: The amount of data written in bytes. |
5438da85 HS |
620 | */ |
621 | unsigned int comedi_buf_write_samples(struct comedi_subdevice *s, | |
622 | const void *data, unsigned int nsamples) | |
623 | { | |
624 | unsigned int max_samples; | |
625 | unsigned int nbytes; | |
626 | ||
eb3a1323 HS |
627 | /* |
628 | * Make sure there is enough room in the buffer for all the samples. | |
629 | * If not, clamp the nsamples to the number that will fit, flag the | |
630 | * buffer overrun and add the samples that fit. | |
631 | */ | |
274ec5ee | 632 | max_samples = comedi_bytes_to_samples(s, comedi_buf_write_n_unalloc(s)); |
5438da85 HS |
633 | if (nsamples > max_samples) { |
634 | dev_warn(s->device->class_dev, "buffer overrun\n"); | |
635 | s->async->events |= COMEDI_CB_OVERFLOW; | |
eb3a1323 | 636 | nsamples = max_samples; |
5438da85 HS |
637 | } |
638 | ||
e19a3c97 HS |
639 | if (nsamples == 0) |
640 | return 0; | |
641 | ||
c39e050d HS |
642 | nbytes = comedi_buf_write_alloc(s, |
643 | comedi_samples_to_bytes(s, nsamples)); | |
e19a3c97 HS |
644 | comedi_buf_memcpy_to(s, data, nbytes); |
645 | comedi_buf_write_free(s, nbytes); | |
646 | comedi_inc_scan_progress(s, nbytes); | |
647 | s->async->events |= COMEDI_CB_BLOCK; | |
5438da85 | 648 | |
e19a3c97 | 649 | return nbytes; |
5438da85 HS |
650 | } |
651 | EXPORT_SYMBOL_GPL(comedi_buf_write_samples); | |
652 | ||
4455d7c3 | 653 | /** |
67ecc3dd IA |
654 | * comedi_buf_read_samples() - Read sample data from COMEDI buffer |
655 | * @s: COMEDI subdevice. | |
656 | * @data: Pointer to destination. | |
657 | * @nsamples: Maximum number of samples to read. | |
4455d7c3 | 658 | * |
67ecc3dd IA |
659 | * Read up to @nsamples samples from the COMEDI acquisition data buffer |
660 | * associated with the subdevice, mark it as read and update the acquisition | |
661 | * scan progress. Limit the number of samples read to the number available. | |
662 | * Set the %COMEDI_CB_BLOCK event flag if any samples are read to cause waiting | |
663 | * tasks to be woken when the event flags are processed. | |
4455d7c3 | 664 | * |
67ecc3dd | 665 | * Return: The amount of data read in bytes. |
4455d7c3 HS |
666 | */ |
667 | unsigned int comedi_buf_read_samples(struct comedi_subdevice *s, | |
668 | void *data, unsigned int nsamples) | |
669 | { | |
670 | unsigned int max_samples; | |
671 | unsigned int nbytes; | |
672 | ||
8de27e70 | 673 | /* clamp nsamples to the number of full samples available */ |
c39e050d HS |
674 | max_samples = comedi_bytes_to_samples(s, |
675 | comedi_buf_read_n_available(s)); | |
4455d7c3 HS |
676 | if (nsamples > max_samples) |
677 | nsamples = max_samples; | |
678 | ||
8de27e70 | 679 | if (nsamples == 0) |
109bf06e | 680 | return 0; |
4455d7c3 | 681 | |
c39e050d HS |
682 | nbytes = comedi_buf_read_alloc(s, |
683 | comedi_samples_to_bytes(s, nsamples)); | |
0ca7f61c | 684 | comedi_buf_memcpy_from(s, data, nbytes); |
109bf06e HS |
685 | comedi_buf_read_free(s, nbytes); |
686 | comedi_inc_scan_progress(s, nbytes); | |
687 | s->async->events |= COMEDI_CB_BLOCK; | |
688 | ||
689 | return nbytes; | |
4455d7c3 HS |
690 | } |
691 | EXPORT_SYMBOL_GPL(comedi_buf_read_samples); |