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10#include <linux/vmalloc.h>
11#include <linux/slab.h>
12
13#include "comedidev.h"
14#include "comedi_internal.h"
15
16#ifdef PAGE_KERNEL_NOCACHE
17#define COMEDI_PAGE_PROTECTION PAGE_KERNEL_NOCACHE
18#else
19#define COMEDI_PAGE_PROTECTION PAGE_KERNEL
20#endif
21
22static void comedi_buf_map_kref_release(struct kref *kref)
23{
24 struct comedi_buf_map *bm =
25 container_of(kref, struct comedi_buf_map, refcount);
26 struct comedi_buf_page *buf;
27 unsigned int i;
28
29 if (bm->page_list) {
30 for (i = 0; i < bm->n_pages; i++) {
31 buf = &bm->page_list[i];
32 clear_bit(PG_reserved,
33 &(virt_to_page(buf->virt_addr)->flags));
34 if (bm->dma_dir != DMA_NONE) {
35#ifdef CONFIG_HAS_DMA
36 dma_free_coherent(bm->dma_hw_dev,
37 PAGE_SIZE,
38 buf->virt_addr,
39 buf->dma_addr);
40#endif
41 } else {
42 free_page((unsigned long)buf->virt_addr);
43 }
44 }
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
52static void __comedi_buf_free(struct comedi_device *dev,
53 struct comedi_subdevice *s)
54{
55 struct comedi_async *async = s->async;
56 struct comedi_buf_map *bm;
57 unsigned long flags;
58
59 if (async->prealloc_buf) {
60 vunmap(async->prealloc_buf);
61 async->prealloc_buf = NULL;
62 async->prealloc_bufsz = 0;
63 }
64
65 spin_lock_irqsave(&s->spin_lock, flags);
66 bm = async->buf_map;
67 async->buf_map = NULL;
68 spin_unlock_irqrestore(&s->spin_lock, flags);
69 comedi_buf_map_put(bm);
70}
71
72static void __comedi_buf_alloc(struct comedi_device *dev,
73 struct comedi_subdevice *s,
74 unsigned int n_pages)
75{
76 struct comedi_async *async = s->async;
77 struct page **pages = NULL;
78 struct comedi_buf_map *bm;
79 struct comedi_buf_page *buf;
80 unsigned long flags;
81 unsigned int i;
82
83 if (!IS_ENABLED(CONFIG_HAS_DMA) && s->async_dma_dir != DMA_NONE) {
84 dev_err(dev->class_dev,
85 "dma buffer allocation not supported\n");
86 return;
87 }
88
89 bm = kzalloc(sizeof(*async->buf_map), GFP_KERNEL);
90 if (!bm)
91 return;
92
93 kref_init(&bm->refcount);
94 spin_lock_irqsave(&s->spin_lock, flags);
95 async->buf_map = bm;
96 spin_unlock_irqrestore(&s->spin_lock, flags);
97 bm->dma_dir = s->async_dma_dir;
98 if (bm->dma_dir != DMA_NONE)
99
100 bm->dma_hw_dev = get_device(dev->hw_dev);
101
102 bm->page_list = vzalloc(sizeof(*buf) * n_pages);
103 if (bm->page_list)
104 pages = vmalloc(sizeof(struct page *) * n_pages);
105
106 if (!pages)
107 return;
108
109 for (i = 0; i < n_pages; i++) {
110 buf = &bm->page_list[i];
111 if (bm->dma_dir != DMA_NONE)
112#ifdef CONFIG_HAS_DMA
113 buf->virt_addr = dma_alloc_coherent(bm->dma_hw_dev,
114 PAGE_SIZE,
115 &buf->dma_addr,
116 GFP_KERNEL |
117 __GFP_COMP);
118#else
119 break;
120#endif
121 else
122 buf->virt_addr = (void *)get_zeroed_page(GFP_KERNEL);
123 if (!buf->virt_addr)
124 break;
125
126 set_bit(PG_reserved, &(virt_to_page(buf->virt_addr)->flags));
127
128 pages[i] = virt_to_page(buf->virt_addr);
129 }
130 spin_lock_irqsave(&s->spin_lock, flags);
131 bm->n_pages = i;
132 spin_unlock_irqrestore(&s->spin_lock, flags);
133
134
135 if (i == n_pages)
136 async->prealloc_buf = vmap(pages, n_pages, VM_MAP,
137 COMEDI_PAGE_PROTECTION);
138
139 vfree(pages);
140}
141
142void comedi_buf_map_get(struct comedi_buf_map *bm)
143{
144 if (bm)
145 kref_get(&bm->refcount);
146}
147
148int comedi_buf_map_put(struct comedi_buf_map *bm)
149{
150 if (bm)
151 return kref_put(&bm->refcount, comedi_buf_map_kref_release);
152 return 1;
153}
154
155
156int comedi_buf_map_access(struct comedi_buf_map *bm, unsigned long offset,
157 void *buf, int len, int write)
158{
159 unsigned int pgoff = offset_in_page(offset);
160 unsigned long pg = offset >> PAGE_SHIFT;
161 int done = 0;
162
163 while (done < len && pg < bm->n_pages) {
164 int l = min_t(int, len - done, PAGE_SIZE - pgoff);
165 void *b = bm->page_list[pg].virt_addr + pgoff;
166
167 if (write)
168 memcpy(b, buf, l);
169 else
170 memcpy(buf, b, l);
171 buf += l;
172 done += l;
173 pg++;
174 pgoff = 0;
175 }
176 return done;
177}
178
179
180struct comedi_buf_map *
181comedi_buf_map_from_subdev_get(struct comedi_subdevice *s)
182{
183 struct comedi_async *async = s->async;
184 struct comedi_buf_map *bm = NULL;
185 unsigned long flags;
186
187 if (!async)
188 return NULL;
189
190 spin_lock_irqsave(&s->spin_lock, flags);
191 bm = async->buf_map;
192
193 if (bm && bm->n_pages)
194 comedi_buf_map_get(bm);
195 else
196 bm = NULL;
197 spin_unlock_irqrestore(&s->spin_lock, flags);
198
199 return bm;
200}
201
202bool comedi_buf_is_mmapped(struct comedi_subdevice *s)
203{
204 struct comedi_buf_map *bm = s->async->buf_map;
205
206 return bm && (kref_read(&bm->refcount) > 1);
207}
208
209int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
210 unsigned long new_size)
211{
212 struct comedi_async *async = s->async;
213
214 lockdep_assert_held(&dev->mutex);
215
216
217 new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
218
219
220 if (async->prealloc_buf && async->prealloc_bufsz == new_size)
221 return 0;
222
223
224 __comedi_buf_free(dev, s);
225
226
227 if (new_size) {
228 unsigned int n_pages = new_size >> PAGE_SHIFT;
229
230 __comedi_buf_alloc(dev, s, n_pages);
231
232 if (!async->prealloc_buf) {
233
234 __comedi_buf_free(dev, s);
235 return -ENOMEM;
236 }
237 }
238 async->prealloc_bufsz = new_size;
239
240 return 0;
241}
242
243void comedi_buf_reset(struct comedi_subdevice *s)
244{
245 struct comedi_async *async = s->async;
246
247 async->buf_write_alloc_count = 0;
248 async->buf_write_count = 0;
249 async->buf_read_alloc_count = 0;
250 async->buf_read_count = 0;
251
252 async->buf_write_ptr = 0;
253 async->buf_read_ptr = 0;
254
255 async->cur_chan = 0;
256 async->scans_done = 0;
257 async->scan_progress = 0;
258 async->munge_chan = 0;
259 async->munge_count = 0;
260 async->munge_ptr = 0;
261
262 async->events = 0;
263}
264
265static unsigned int comedi_buf_write_n_unalloc(struct comedi_subdevice *s)
266{
267 struct comedi_async *async = s->async;
268 unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
269
270 return free_end - async->buf_write_alloc_count;
271}
272
273unsigned int comedi_buf_write_n_available(struct comedi_subdevice *s)
274{
275 struct comedi_async *async = s->async;
276 unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
277
278 return free_end - async->buf_write_count;
279}
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292unsigned int comedi_buf_write_alloc(struct comedi_subdevice *s,
293 unsigned int nbytes)
294{
295 struct comedi_async *async = s->async;
296 unsigned int unalloc = comedi_buf_write_n_unalloc(s);
297
298 if (nbytes > unalloc)
299 nbytes = unalloc;
300
301 async->buf_write_alloc_count += nbytes;
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307 smp_mb();
308
309 return nbytes;
310}
311EXPORT_SYMBOL_GPL(comedi_buf_write_alloc);
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316
317static unsigned int comedi_buf_munge(struct comedi_subdevice *s,
318 unsigned int num_bytes)
319{
320 struct comedi_async *async = s->async;
321 unsigned int count = 0;
322 const unsigned int num_sample_bytes = comedi_bytes_per_sample(s);
323
324 if (!s->munge || (async->cmd.flags & CMDF_RAWDATA)) {
325 async->munge_count += num_bytes;
326 count = num_bytes;
327 } else {
328
329 num_bytes -= num_bytes % num_sample_bytes;
330 while (count < num_bytes) {
331 int block_size = num_bytes - count;
332 unsigned int buf_end;
333
334 buf_end = async->prealloc_bufsz - async->munge_ptr;
335 if (block_size > buf_end)
336 block_size = buf_end;
337
338 s->munge(s->device, s,
339 async->prealloc_buf + async->munge_ptr,
340 block_size, async->munge_chan);
341
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346 smp_wmb();
347
348 async->munge_chan += block_size / num_sample_bytes;
349 async->munge_chan %= async->cmd.chanlist_len;
350 async->munge_count += block_size;
351 async->munge_ptr += block_size;
352 async->munge_ptr %= async->prealloc_bufsz;
353 count += block_size;
354 }
355 }
356
357 return count;
358}
359
360unsigned int comedi_buf_write_n_allocated(struct comedi_subdevice *s)
361{
362 struct comedi_async *async = s->async;
363
364 return async->buf_write_alloc_count - async->buf_write_count;
365}
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382unsigned int comedi_buf_write_free(struct comedi_subdevice *s,
383 unsigned int nbytes)
384{
385 struct comedi_async *async = s->async;
386 unsigned int allocated = comedi_buf_write_n_allocated(s);
387
388 if (nbytes > allocated)
389 nbytes = allocated;
390
391 async->buf_write_count += nbytes;
392 async->buf_write_ptr += nbytes;
393 comedi_buf_munge(s, async->buf_write_count - async->munge_count);
394 if (async->buf_write_ptr >= async->prealloc_bufsz)
395 async->buf_write_ptr %= async->prealloc_bufsz;
396
397 return nbytes;
398}
399EXPORT_SYMBOL_GPL(comedi_buf_write_free);
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412unsigned int comedi_buf_read_n_available(struct comedi_subdevice *s)
413{
414 struct comedi_async *async = s->async;
415 unsigned int num_bytes;
416
417 if (!async)
418 return 0;
419
420 num_bytes = async->munge_count - async->buf_read_count;
421
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426 smp_rmb();
427
428 return num_bytes;
429}
430EXPORT_SYMBOL_GPL(comedi_buf_read_n_available);
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447unsigned int comedi_buf_read_alloc(struct comedi_subdevice *s,
448 unsigned int nbytes)
449{
450 struct comedi_async *async = s->async;
451 unsigned int available;
452
453 available = async->munge_count - async->buf_read_alloc_count;
454 if (nbytes > available)
455 nbytes = available;
456
457 async->buf_read_alloc_count += nbytes;
458
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463 smp_rmb();
464
465 return nbytes;
466}
467EXPORT_SYMBOL_GPL(comedi_buf_read_alloc);
468
469static unsigned int comedi_buf_read_n_allocated(struct comedi_async *async)
470{
471 return async->buf_read_alloc_count - async->buf_read_count;
472}
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487unsigned int comedi_buf_read_free(struct comedi_subdevice *s,
488 unsigned int nbytes)
489{
490 struct comedi_async *async = s->async;
491 unsigned int allocated;
492
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497 smp_mb();
498
499 allocated = comedi_buf_read_n_allocated(async);
500 if (nbytes > allocated)
501 nbytes = allocated;
502
503 async->buf_read_count += nbytes;
504 async->buf_read_ptr += nbytes;
505 async->buf_read_ptr %= async->prealloc_bufsz;
506 return nbytes;
507}
508EXPORT_SYMBOL_GPL(comedi_buf_read_free);
509
510static void comedi_buf_memcpy_to(struct comedi_subdevice *s,
511 const void *data, unsigned int num_bytes)
512{
513 struct comedi_async *async = s->async;
514 unsigned int write_ptr = async->buf_write_ptr;
515
516 while (num_bytes) {
517 unsigned int block_size;
518
519 if (write_ptr + num_bytes > async->prealloc_bufsz)
520 block_size = async->prealloc_bufsz - write_ptr;
521 else
522 block_size = num_bytes;
523
524 memcpy(async->prealloc_buf + write_ptr, data, block_size);
525
526 data += block_size;
527 num_bytes -= block_size;
528
529 write_ptr = 0;
530 }
531}
532
533static void comedi_buf_memcpy_from(struct comedi_subdevice *s,
534 void *dest, unsigned int nbytes)
535{
536 void *src;
537 struct comedi_async *async = s->async;
538 unsigned int read_ptr = async->buf_read_ptr;
539
540 while (nbytes) {
541 unsigned int block_size;
542
543 src = async->prealloc_buf + read_ptr;
544
545 if (nbytes >= async->prealloc_bufsz - read_ptr)
546 block_size = async->prealloc_bufsz - read_ptr;
547 else
548 block_size = nbytes;
549
550 memcpy(dest, src, block_size);
551 nbytes -= block_size;
552 dest += block_size;
553 read_ptr = 0;
554 }
555}
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574unsigned int comedi_buf_write_samples(struct comedi_subdevice *s,
575 const void *data, unsigned int nsamples)
576{
577 unsigned int max_samples;
578 unsigned int nbytes;
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585 max_samples = comedi_bytes_to_samples(s, comedi_buf_write_n_unalloc(s));
586 if (nsamples > max_samples) {
587 dev_warn(s->device->class_dev, "buffer overrun\n");
588 s->async->events |= COMEDI_CB_OVERFLOW;
589 nsamples = max_samples;
590 }
591
592 if (nsamples == 0)
593 return 0;
594
595 nbytes = comedi_buf_write_alloc(s,
596 comedi_samples_to_bytes(s, nsamples));
597 comedi_buf_memcpy_to(s, data, nbytes);
598 comedi_buf_write_free(s, nbytes);
599 comedi_inc_scan_progress(s, nbytes);
600 s->async->events |= COMEDI_CB_BLOCK;
601
602 return nbytes;
603}
604EXPORT_SYMBOL_GPL(comedi_buf_write_samples);
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620unsigned int comedi_buf_read_samples(struct comedi_subdevice *s,
621 void *data, unsigned int nsamples)
622{
623 unsigned int max_samples;
624 unsigned int nbytes;
625
626
627 max_samples = comedi_bytes_to_samples(s,
628 comedi_buf_read_n_available(s));
629 if (nsamples > max_samples)
630 nsamples = max_samples;
631
632 if (nsamples == 0)
633 return 0;
634
635 nbytes = comedi_buf_read_alloc(s,
636 comedi_samples_to_bytes(s, nsamples));
637 comedi_buf_memcpy_from(s, data, nbytes);
638 comedi_buf_read_free(s, nbytes);
639 comedi_inc_scan_progress(s, nbytes);
640 s->async->events |= COMEDI_CB_BLOCK;
641
642 return nbytes;
643}
644EXPORT_SYMBOL_GPL(comedi_buf_read_samples);
645