xref: /linux/sound/core/pcm_lib.c (revision 0d456bad36d42d16022be045c8a53ddbb59ee478)
1 /*
2  *  Digital Audio (PCM) abstract layer
3  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
4  *                   Abramo Bagnara <abramo@alsa-project.org>
5  *
6  *
7  *   This program is free software; you can redistribute it and/or modify
8  *   it under the terms of the GNU General Public License as published by
9  *   the Free Software Foundation; either version 2 of the License, or
10  *   (at your option) any later version.
11  *
12  *   This program is distributed in the hope that it will be useful,
13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *   GNU General Public License for more details.
16  *
17  *   You should have received a copy of the GNU General Public License
18  *   along with this program; if not, write to the Free Software
19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
20  *
21  */
22 
23 #include <linux/slab.h>
24 #include <linux/time.h>
25 #include <linux/math64.h>
26 #include <linux/export.h>
27 #include <sound/core.h>
28 #include <sound/control.h>
29 #include <sound/tlv.h>
30 #include <sound/info.h>
31 #include <sound/pcm.h>
32 #include <sound/pcm_params.h>
33 #include <sound/timer.h>
34 
35 /*
36  * fill ring buffer with silence
37  * runtime->silence_start: starting pointer to silence area
38  * runtime->silence_filled: size filled with silence
39  * runtime->silence_threshold: threshold from application
40  * runtime->silence_size: maximal size from application
41  *
42  * when runtime->silence_size >= runtime->boundary - fill processed area with silence immediately
43  */
44 void snd_pcm_playback_silence(struct snd_pcm_substream *substream, snd_pcm_uframes_t new_hw_ptr)
45 {
46 	struct snd_pcm_runtime *runtime = substream->runtime;
47 	snd_pcm_uframes_t frames, ofs, transfer;
48 
49 	if (runtime->silence_size < runtime->boundary) {
50 		snd_pcm_sframes_t noise_dist, n;
51 		if (runtime->silence_start != runtime->control->appl_ptr) {
52 			n = runtime->control->appl_ptr - runtime->silence_start;
53 			if (n < 0)
54 				n += runtime->boundary;
55 			if ((snd_pcm_uframes_t)n < runtime->silence_filled)
56 				runtime->silence_filled -= n;
57 			else
58 				runtime->silence_filled = 0;
59 			runtime->silence_start = runtime->control->appl_ptr;
60 		}
61 		if (runtime->silence_filled >= runtime->buffer_size)
62 			return;
63 		noise_dist = snd_pcm_playback_hw_avail(runtime) + runtime->silence_filled;
64 		if (noise_dist >= (snd_pcm_sframes_t) runtime->silence_threshold)
65 			return;
66 		frames = runtime->silence_threshold - noise_dist;
67 		if (frames > runtime->silence_size)
68 			frames = runtime->silence_size;
69 	} else {
70 		if (new_hw_ptr == ULONG_MAX) {	/* initialization */
71 			snd_pcm_sframes_t avail = snd_pcm_playback_hw_avail(runtime);
72 			if (avail > runtime->buffer_size)
73 				avail = runtime->buffer_size;
74 			runtime->silence_filled = avail > 0 ? avail : 0;
75 			runtime->silence_start = (runtime->status->hw_ptr +
76 						  runtime->silence_filled) %
77 						 runtime->boundary;
78 		} else {
79 			ofs = runtime->status->hw_ptr;
80 			frames = new_hw_ptr - ofs;
81 			if ((snd_pcm_sframes_t)frames < 0)
82 				frames += runtime->boundary;
83 			runtime->silence_filled -= frames;
84 			if ((snd_pcm_sframes_t)runtime->silence_filled < 0) {
85 				runtime->silence_filled = 0;
86 				runtime->silence_start = new_hw_ptr;
87 			} else {
88 				runtime->silence_start = ofs;
89 			}
90 		}
91 		frames = runtime->buffer_size - runtime->silence_filled;
92 	}
93 	if (snd_BUG_ON(frames > runtime->buffer_size))
94 		return;
95 	if (frames == 0)
96 		return;
97 	ofs = runtime->silence_start % runtime->buffer_size;
98 	while (frames > 0) {
99 		transfer = ofs + frames > runtime->buffer_size ? runtime->buffer_size - ofs : frames;
100 		if (runtime->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED ||
101 		    runtime->access == SNDRV_PCM_ACCESS_MMAP_INTERLEAVED) {
102 			if (substream->ops->silence) {
103 				int err;
104 				err = substream->ops->silence(substream, -1, ofs, transfer);
105 				snd_BUG_ON(err < 0);
106 			} else {
107 				char *hwbuf = runtime->dma_area + frames_to_bytes(runtime, ofs);
108 				snd_pcm_format_set_silence(runtime->format, hwbuf, transfer * runtime->channels);
109 			}
110 		} else {
111 			unsigned int c;
112 			unsigned int channels = runtime->channels;
113 			if (substream->ops->silence) {
114 				for (c = 0; c < channels; ++c) {
115 					int err;
116 					err = substream->ops->silence(substream, c, ofs, transfer);
117 					snd_BUG_ON(err < 0);
118 				}
119 			} else {
120 				size_t dma_csize = runtime->dma_bytes / channels;
121 				for (c = 0; c < channels; ++c) {
122 					char *hwbuf = runtime->dma_area + (c * dma_csize) + samples_to_bytes(runtime, ofs);
123 					snd_pcm_format_set_silence(runtime->format, hwbuf, transfer);
124 				}
125 			}
126 		}
127 		runtime->silence_filled += transfer;
128 		frames -= transfer;
129 		ofs = 0;
130 	}
131 }
132 
133 #ifdef CONFIG_SND_DEBUG
134 void snd_pcm_debug_name(struct snd_pcm_substream *substream,
135 			   char *name, size_t len)
136 {
137 	snprintf(name, len, "pcmC%dD%d%c:%d",
138 		 substream->pcm->card->number,
139 		 substream->pcm->device,
140 		 substream->stream ? 'c' : 'p',
141 		 substream->number);
142 }
143 EXPORT_SYMBOL(snd_pcm_debug_name);
144 #endif
145 
146 #define XRUN_DEBUG_BASIC	(1<<0)
147 #define XRUN_DEBUG_STACK	(1<<1)	/* dump also stack */
148 #define XRUN_DEBUG_JIFFIESCHECK	(1<<2)	/* do jiffies check */
149 #define XRUN_DEBUG_PERIODUPDATE	(1<<3)	/* full period update info */
150 #define XRUN_DEBUG_HWPTRUPDATE	(1<<4)	/* full hwptr update info */
151 #define XRUN_DEBUG_LOG		(1<<5)	/* show last 10 positions on err */
152 #define XRUN_DEBUG_LOGONCE	(1<<6)	/* do above only once */
153 
154 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
155 
156 #define xrun_debug(substream, mask) \
157 			((substream)->pstr->xrun_debug & (mask))
158 #else
159 #define xrun_debug(substream, mask)	0
160 #endif
161 
162 #define dump_stack_on_xrun(substream) do {			\
163 		if (xrun_debug(substream, XRUN_DEBUG_STACK))	\
164 			dump_stack();				\
165 	} while (0)
166 
167 static void xrun(struct snd_pcm_substream *substream)
168 {
169 	struct snd_pcm_runtime *runtime = substream->runtime;
170 
171 	if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE)
172 		snd_pcm_gettime(runtime, (struct timespec *)&runtime->status->tstamp);
173 	snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
174 	if (xrun_debug(substream, XRUN_DEBUG_BASIC)) {
175 		char name[16];
176 		snd_pcm_debug_name(substream, name, sizeof(name));
177 		snd_printd(KERN_DEBUG "XRUN: %s\n", name);
178 		dump_stack_on_xrun(substream);
179 	}
180 }
181 
182 #ifdef CONFIG_SND_PCM_XRUN_DEBUG
183 #define hw_ptr_error(substream, fmt, args...)				\
184 	do {								\
185 		if (xrun_debug(substream, XRUN_DEBUG_BASIC)) {		\
186 			xrun_log_show(substream);			\
187 			if (printk_ratelimit()) {			\
188 				snd_printd("PCM: " fmt, ##args);	\
189 			}						\
190 			dump_stack_on_xrun(substream);			\
191 		}							\
192 	} while (0)
193 
194 #define XRUN_LOG_CNT	10
195 
196 struct hwptr_log_entry {
197 	unsigned int in_interrupt;
198 	unsigned long jiffies;
199 	snd_pcm_uframes_t pos;
200 	snd_pcm_uframes_t period_size;
201 	snd_pcm_uframes_t buffer_size;
202 	snd_pcm_uframes_t old_hw_ptr;
203 	snd_pcm_uframes_t hw_ptr_base;
204 };
205 
206 struct snd_pcm_hwptr_log {
207 	unsigned int idx;
208 	unsigned int hit: 1;
209 	struct hwptr_log_entry entries[XRUN_LOG_CNT];
210 };
211 
212 static void xrun_log(struct snd_pcm_substream *substream,
213 		     snd_pcm_uframes_t pos, int in_interrupt)
214 {
215 	struct snd_pcm_runtime *runtime = substream->runtime;
216 	struct snd_pcm_hwptr_log *log = runtime->hwptr_log;
217 	struct hwptr_log_entry *entry;
218 
219 	if (log == NULL) {
220 		log = kzalloc(sizeof(*log), GFP_ATOMIC);
221 		if (log == NULL)
222 			return;
223 		runtime->hwptr_log = log;
224 	} else {
225 		if (xrun_debug(substream, XRUN_DEBUG_LOGONCE) && log->hit)
226 			return;
227 	}
228 	entry = &log->entries[log->idx];
229 	entry->in_interrupt = in_interrupt;
230 	entry->jiffies = jiffies;
231 	entry->pos = pos;
232 	entry->period_size = runtime->period_size;
233 	entry->buffer_size = runtime->buffer_size;
234 	entry->old_hw_ptr = runtime->status->hw_ptr;
235 	entry->hw_ptr_base = runtime->hw_ptr_base;
236 	log->idx = (log->idx + 1) % XRUN_LOG_CNT;
237 }
238 
239 static void xrun_log_show(struct snd_pcm_substream *substream)
240 {
241 	struct snd_pcm_hwptr_log *log = substream->runtime->hwptr_log;
242 	struct hwptr_log_entry *entry;
243 	char name[16];
244 	unsigned int idx;
245 	int cnt;
246 
247 	if (log == NULL)
248 		return;
249 	if (xrun_debug(substream, XRUN_DEBUG_LOGONCE) && log->hit)
250 		return;
251 	snd_pcm_debug_name(substream, name, sizeof(name));
252 	for (cnt = 0, idx = log->idx; cnt < XRUN_LOG_CNT; cnt++) {
253 		entry = &log->entries[idx];
254 		if (entry->period_size == 0)
255 			break;
256 		snd_printd("hwptr log: %s: %sj=%lu, pos=%ld/%ld/%ld, "
257 			   "hwptr=%ld/%ld\n",
258 			   name, entry->in_interrupt ? "[Q] " : "",
259 			   entry->jiffies,
260 			   (unsigned long)entry->pos,
261 			   (unsigned long)entry->period_size,
262 			   (unsigned long)entry->buffer_size,
263 			   (unsigned long)entry->old_hw_ptr,
264 			   (unsigned long)entry->hw_ptr_base);
265 		idx++;
266 		idx %= XRUN_LOG_CNT;
267 	}
268 	log->hit = 1;
269 }
270 
271 #else /* ! CONFIG_SND_PCM_XRUN_DEBUG */
272 
273 #define hw_ptr_error(substream, fmt, args...) do { } while (0)
274 #define xrun_log(substream, pos, in_interrupt)	do { } while (0)
275 #define xrun_log_show(substream)	do { } while (0)
276 
277 #endif
278 
279 int snd_pcm_update_state(struct snd_pcm_substream *substream,
280 			 struct snd_pcm_runtime *runtime)
281 {
282 	snd_pcm_uframes_t avail;
283 
284 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
285 		avail = snd_pcm_playback_avail(runtime);
286 	else
287 		avail = snd_pcm_capture_avail(runtime);
288 	if (avail > runtime->avail_max)
289 		runtime->avail_max = avail;
290 	if (runtime->status->state == SNDRV_PCM_STATE_DRAINING) {
291 		if (avail >= runtime->buffer_size) {
292 			snd_pcm_drain_done(substream);
293 			return -EPIPE;
294 		}
295 	} else {
296 		if (avail >= runtime->stop_threshold) {
297 			xrun(substream);
298 			return -EPIPE;
299 		}
300 	}
301 	if (runtime->twake) {
302 		if (avail >= runtime->twake)
303 			wake_up(&runtime->tsleep);
304 	} else if (avail >= runtime->control->avail_min)
305 		wake_up(&runtime->sleep);
306 	return 0;
307 }
308 
309 static int snd_pcm_update_hw_ptr0(struct snd_pcm_substream *substream,
310 				  unsigned int in_interrupt)
311 {
312 	struct snd_pcm_runtime *runtime = substream->runtime;
313 	snd_pcm_uframes_t pos;
314 	snd_pcm_uframes_t old_hw_ptr, new_hw_ptr, hw_base;
315 	snd_pcm_sframes_t hdelta, delta;
316 	unsigned long jdelta;
317 	unsigned long curr_jiffies;
318 	struct timespec curr_tstamp;
319 	struct timespec audio_tstamp;
320 	int crossed_boundary = 0;
321 
322 	old_hw_ptr = runtime->status->hw_ptr;
323 
324 	/*
325 	 * group pointer, time and jiffies reads to allow for more
326 	 * accurate correlations/corrections.
327 	 * The values are stored at the end of this routine after
328 	 * corrections for hw_ptr position
329 	 */
330 	pos = substream->ops->pointer(substream);
331 	curr_jiffies = jiffies;
332 	if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE) {
333 		snd_pcm_gettime(runtime, (struct timespec *)&curr_tstamp);
334 
335 		if ((runtime->hw.info & SNDRV_PCM_INFO_HAS_WALL_CLOCK) &&
336 			(substream->ops->wall_clock))
337 			substream->ops->wall_clock(substream, &audio_tstamp);
338 	}
339 
340 	if (pos == SNDRV_PCM_POS_XRUN) {
341 		xrun(substream);
342 		return -EPIPE;
343 	}
344 	if (pos >= runtime->buffer_size) {
345 		if (printk_ratelimit()) {
346 			char name[16];
347 			snd_pcm_debug_name(substream, name, sizeof(name));
348 			xrun_log_show(substream);
349 			snd_printd(KERN_ERR  "BUG: %s, pos = %ld, "
350 				   "buffer size = %ld, period size = %ld\n",
351 				   name, pos, runtime->buffer_size,
352 				   runtime->period_size);
353 		}
354 		pos = 0;
355 	}
356 	pos -= pos % runtime->min_align;
357 	if (xrun_debug(substream, XRUN_DEBUG_LOG))
358 		xrun_log(substream, pos, in_interrupt);
359 	hw_base = runtime->hw_ptr_base;
360 	new_hw_ptr = hw_base + pos;
361 	if (in_interrupt) {
362 		/* we know that one period was processed */
363 		/* delta = "expected next hw_ptr" for in_interrupt != 0 */
364 		delta = runtime->hw_ptr_interrupt + runtime->period_size;
365 		if (delta > new_hw_ptr) {
366 			/* check for double acknowledged interrupts */
367 			hdelta = curr_jiffies - runtime->hw_ptr_jiffies;
368 			if (hdelta > runtime->hw_ptr_buffer_jiffies/2) {
369 				hw_base += runtime->buffer_size;
370 				if (hw_base >= runtime->boundary) {
371 					hw_base = 0;
372 					crossed_boundary++;
373 				}
374 				new_hw_ptr = hw_base + pos;
375 				goto __delta;
376 			}
377 		}
378 	}
379 	/* new_hw_ptr might be lower than old_hw_ptr in case when */
380 	/* pointer crosses the end of the ring buffer */
381 	if (new_hw_ptr < old_hw_ptr) {
382 		hw_base += runtime->buffer_size;
383 		if (hw_base >= runtime->boundary) {
384 			hw_base = 0;
385 			crossed_boundary++;
386 		}
387 		new_hw_ptr = hw_base + pos;
388 	}
389       __delta:
390 	delta = new_hw_ptr - old_hw_ptr;
391 	if (delta < 0)
392 		delta += runtime->boundary;
393 	if (xrun_debug(substream, in_interrupt ?
394 			XRUN_DEBUG_PERIODUPDATE : XRUN_DEBUG_HWPTRUPDATE)) {
395 		char name[16];
396 		snd_pcm_debug_name(substream, name, sizeof(name));
397 		snd_printd("%s_update: %s: pos=%u/%u/%u, "
398 			   "hwptr=%ld/%ld/%ld/%ld\n",
399 			   in_interrupt ? "period" : "hwptr",
400 			   name,
401 			   (unsigned int)pos,
402 			   (unsigned int)runtime->period_size,
403 			   (unsigned int)runtime->buffer_size,
404 			   (unsigned long)delta,
405 			   (unsigned long)old_hw_ptr,
406 			   (unsigned long)new_hw_ptr,
407 			   (unsigned long)runtime->hw_ptr_base);
408 	}
409 
410 	if (runtime->no_period_wakeup) {
411 		snd_pcm_sframes_t xrun_threshold;
412 		/*
413 		 * Without regular period interrupts, we have to check
414 		 * the elapsed time to detect xruns.
415 		 */
416 		jdelta = curr_jiffies - runtime->hw_ptr_jiffies;
417 		if (jdelta < runtime->hw_ptr_buffer_jiffies / 2)
418 			goto no_delta_check;
419 		hdelta = jdelta - delta * HZ / runtime->rate;
420 		xrun_threshold = runtime->hw_ptr_buffer_jiffies / 2 + 1;
421 		while (hdelta > xrun_threshold) {
422 			delta += runtime->buffer_size;
423 			hw_base += runtime->buffer_size;
424 			if (hw_base >= runtime->boundary) {
425 				hw_base = 0;
426 				crossed_boundary++;
427 			}
428 			new_hw_ptr = hw_base + pos;
429 			hdelta -= runtime->hw_ptr_buffer_jiffies;
430 		}
431 		goto no_delta_check;
432 	}
433 
434 	/* something must be really wrong */
435 	if (delta >= runtime->buffer_size + runtime->period_size) {
436 		hw_ptr_error(substream,
437 			       "Unexpected hw_pointer value %s"
438 			       "(stream=%i, pos=%ld, new_hw_ptr=%ld, "
439 			       "old_hw_ptr=%ld)\n",
440 				     in_interrupt ? "[Q] " : "[P]",
441 				     substream->stream, (long)pos,
442 				     (long)new_hw_ptr, (long)old_hw_ptr);
443 		return 0;
444 	}
445 
446 	/* Do jiffies check only in xrun_debug mode */
447 	if (!xrun_debug(substream, XRUN_DEBUG_JIFFIESCHECK))
448 		goto no_jiffies_check;
449 
450 	/* Skip the jiffies check for hardwares with BATCH flag.
451 	 * Such hardware usually just increases the position at each IRQ,
452 	 * thus it can't give any strange position.
453 	 */
454 	if (runtime->hw.info & SNDRV_PCM_INFO_BATCH)
455 		goto no_jiffies_check;
456 	hdelta = delta;
457 	if (hdelta < runtime->delay)
458 		goto no_jiffies_check;
459 	hdelta -= runtime->delay;
460 	jdelta = curr_jiffies - runtime->hw_ptr_jiffies;
461 	if (((hdelta * HZ) / runtime->rate) > jdelta + HZ/100) {
462 		delta = jdelta /
463 			(((runtime->period_size * HZ) / runtime->rate)
464 								+ HZ/100);
465 		/* move new_hw_ptr according jiffies not pos variable */
466 		new_hw_ptr = old_hw_ptr;
467 		hw_base = delta;
468 		/* use loop to avoid checks for delta overflows */
469 		/* the delta value is small or zero in most cases */
470 		while (delta > 0) {
471 			new_hw_ptr += runtime->period_size;
472 			if (new_hw_ptr >= runtime->boundary) {
473 				new_hw_ptr -= runtime->boundary;
474 				crossed_boundary--;
475 			}
476 			delta--;
477 		}
478 		/* align hw_base to buffer_size */
479 		hw_ptr_error(substream,
480 			     "hw_ptr skipping! %s"
481 			     "(pos=%ld, delta=%ld, period=%ld, "
482 			     "jdelta=%lu/%lu/%lu, hw_ptr=%ld/%ld)\n",
483 			     in_interrupt ? "[Q] " : "",
484 			     (long)pos, (long)hdelta,
485 			     (long)runtime->period_size, jdelta,
486 			     ((hdelta * HZ) / runtime->rate), hw_base,
487 			     (unsigned long)old_hw_ptr,
488 			     (unsigned long)new_hw_ptr);
489 		/* reset values to proper state */
490 		delta = 0;
491 		hw_base = new_hw_ptr - (new_hw_ptr % runtime->buffer_size);
492 	}
493  no_jiffies_check:
494 	if (delta > runtime->period_size + runtime->period_size / 2) {
495 		hw_ptr_error(substream,
496 			     "Lost interrupts? %s"
497 			     "(stream=%i, delta=%ld, new_hw_ptr=%ld, "
498 			     "old_hw_ptr=%ld)\n",
499 			     in_interrupt ? "[Q] " : "",
500 			     substream->stream, (long)delta,
501 			     (long)new_hw_ptr,
502 			     (long)old_hw_ptr);
503 	}
504 
505  no_delta_check:
506 	if (runtime->status->hw_ptr == new_hw_ptr)
507 		return 0;
508 
509 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
510 	    runtime->silence_size > 0)
511 		snd_pcm_playback_silence(substream, new_hw_ptr);
512 
513 	if (in_interrupt) {
514 		delta = new_hw_ptr - runtime->hw_ptr_interrupt;
515 		if (delta < 0)
516 			delta += runtime->boundary;
517 		delta -= (snd_pcm_uframes_t)delta % runtime->period_size;
518 		runtime->hw_ptr_interrupt += delta;
519 		if (runtime->hw_ptr_interrupt >= runtime->boundary)
520 			runtime->hw_ptr_interrupt -= runtime->boundary;
521 	}
522 	runtime->hw_ptr_base = hw_base;
523 	runtime->status->hw_ptr = new_hw_ptr;
524 	runtime->hw_ptr_jiffies = curr_jiffies;
525 	if (crossed_boundary) {
526 		snd_BUG_ON(crossed_boundary != 1);
527 		runtime->hw_ptr_wrap += runtime->boundary;
528 	}
529 	if (runtime->tstamp_mode == SNDRV_PCM_TSTAMP_ENABLE) {
530 		runtime->status->tstamp = curr_tstamp;
531 
532 		if (!(runtime->hw.info & SNDRV_PCM_INFO_HAS_WALL_CLOCK)) {
533 			/*
534 			 * no wall clock available, provide audio timestamp
535 			 * derived from pointer position+delay
536 			 */
537 			u64 audio_frames, audio_nsecs;
538 
539 			if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
540 				audio_frames = runtime->hw_ptr_wrap
541 					+ runtime->status->hw_ptr
542 					- runtime->delay;
543 			else
544 				audio_frames = runtime->hw_ptr_wrap
545 					+ runtime->status->hw_ptr
546 					+ runtime->delay;
547 			audio_nsecs = div_u64(audio_frames * 1000000000LL,
548 					runtime->rate);
549 			audio_tstamp = ns_to_timespec(audio_nsecs);
550 		}
551 		runtime->status->audio_tstamp = audio_tstamp;
552 	}
553 
554 	return snd_pcm_update_state(substream, runtime);
555 }
556 
557 /* CAUTION: call it with irq disabled */
558 int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream)
559 {
560 	return snd_pcm_update_hw_ptr0(substream, 0);
561 }
562 
563 /**
564  * snd_pcm_set_ops - set the PCM operators
565  * @pcm: the pcm instance
566  * @direction: stream direction, SNDRV_PCM_STREAM_XXX
567  * @ops: the operator table
568  *
569  * Sets the given PCM operators to the pcm instance.
570  */
571 void snd_pcm_set_ops(struct snd_pcm *pcm, int direction, struct snd_pcm_ops *ops)
572 {
573 	struct snd_pcm_str *stream = &pcm->streams[direction];
574 	struct snd_pcm_substream *substream;
575 
576 	for (substream = stream->substream; substream != NULL; substream = substream->next)
577 		substream->ops = ops;
578 }
579 
580 EXPORT_SYMBOL(snd_pcm_set_ops);
581 
582 /**
583  * snd_pcm_sync - set the PCM sync id
584  * @substream: the pcm substream
585  *
586  * Sets the PCM sync identifier for the card.
587  */
588 void snd_pcm_set_sync(struct snd_pcm_substream *substream)
589 {
590 	struct snd_pcm_runtime *runtime = substream->runtime;
591 
592 	runtime->sync.id32[0] = substream->pcm->card->number;
593 	runtime->sync.id32[1] = -1;
594 	runtime->sync.id32[2] = -1;
595 	runtime->sync.id32[3] = -1;
596 }
597 
598 EXPORT_SYMBOL(snd_pcm_set_sync);
599 
600 /*
601  *  Standard ioctl routine
602  */
603 
604 static inline unsigned int div32(unsigned int a, unsigned int b,
605 				 unsigned int *r)
606 {
607 	if (b == 0) {
608 		*r = 0;
609 		return UINT_MAX;
610 	}
611 	*r = a % b;
612 	return a / b;
613 }
614 
615 static inline unsigned int div_down(unsigned int a, unsigned int b)
616 {
617 	if (b == 0)
618 		return UINT_MAX;
619 	return a / b;
620 }
621 
622 static inline unsigned int div_up(unsigned int a, unsigned int b)
623 {
624 	unsigned int r;
625 	unsigned int q;
626 	if (b == 0)
627 		return UINT_MAX;
628 	q = div32(a, b, &r);
629 	if (r)
630 		++q;
631 	return q;
632 }
633 
634 static inline unsigned int mul(unsigned int a, unsigned int b)
635 {
636 	if (a == 0)
637 		return 0;
638 	if (div_down(UINT_MAX, a) < b)
639 		return UINT_MAX;
640 	return a * b;
641 }
642 
643 static inline unsigned int muldiv32(unsigned int a, unsigned int b,
644 				    unsigned int c, unsigned int *r)
645 {
646 	u_int64_t n = (u_int64_t) a * b;
647 	if (c == 0) {
648 		snd_BUG_ON(!n);
649 		*r = 0;
650 		return UINT_MAX;
651 	}
652 	n = div_u64_rem(n, c, r);
653 	if (n >= UINT_MAX) {
654 		*r = 0;
655 		return UINT_MAX;
656 	}
657 	return n;
658 }
659 
660 /**
661  * snd_interval_refine - refine the interval value of configurator
662  * @i: the interval value to refine
663  * @v: the interval value to refer to
664  *
665  * Refines the interval value with the reference value.
666  * The interval is changed to the range satisfying both intervals.
667  * The interval status (min, max, integer, etc.) are evaluated.
668  *
669  * Returns non-zero if the value is changed, zero if not changed.
670  */
671 int snd_interval_refine(struct snd_interval *i, const struct snd_interval *v)
672 {
673 	int changed = 0;
674 	if (snd_BUG_ON(snd_interval_empty(i)))
675 		return -EINVAL;
676 	if (i->min < v->min) {
677 		i->min = v->min;
678 		i->openmin = v->openmin;
679 		changed = 1;
680 	} else if (i->min == v->min && !i->openmin && v->openmin) {
681 		i->openmin = 1;
682 		changed = 1;
683 	}
684 	if (i->max > v->max) {
685 		i->max = v->max;
686 		i->openmax = v->openmax;
687 		changed = 1;
688 	} else if (i->max == v->max && !i->openmax && v->openmax) {
689 		i->openmax = 1;
690 		changed = 1;
691 	}
692 	if (!i->integer && v->integer) {
693 		i->integer = 1;
694 		changed = 1;
695 	}
696 	if (i->integer) {
697 		if (i->openmin) {
698 			i->min++;
699 			i->openmin = 0;
700 		}
701 		if (i->openmax) {
702 			i->max--;
703 			i->openmax = 0;
704 		}
705 	} else if (!i->openmin && !i->openmax && i->min == i->max)
706 		i->integer = 1;
707 	if (snd_interval_checkempty(i)) {
708 		snd_interval_none(i);
709 		return -EINVAL;
710 	}
711 	return changed;
712 }
713 
714 EXPORT_SYMBOL(snd_interval_refine);
715 
716 static int snd_interval_refine_first(struct snd_interval *i)
717 {
718 	if (snd_BUG_ON(snd_interval_empty(i)))
719 		return -EINVAL;
720 	if (snd_interval_single(i))
721 		return 0;
722 	i->max = i->min;
723 	i->openmax = i->openmin;
724 	if (i->openmax)
725 		i->max++;
726 	return 1;
727 }
728 
729 static int snd_interval_refine_last(struct snd_interval *i)
730 {
731 	if (snd_BUG_ON(snd_interval_empty(i)))
732 		return -EINVAL;
733 	if (snd_interval_single(i))
734 		return 0;
735 	i->min = i->max;
736 	i->openmin = i->openmax;
737 	if (i->openmin)
738 		i->min--;
739 	return 1;
740 }
741 
742 void snd_interval_mul(const struct snd_interval *a, const struct snd_interval *b, struct snd_interval *c)
743 {
744 	if (a->empty || b->empty) {
745 		snd_interval_none(c);
746 		return;
747 	}
748 	c->empty = 0;
749 	c->min = mul(a->min, b->min);
750 	c->openmin = (a->openmin || b->openmin);
751 	c->max = mul(a->max,  b->max);
752 	c->openmax = (a->openmax || b->openmax);
753 	c->integer = (a->integer && b->integer);
754 }
755 
756 /**
757  * snd_interval_div - refine the interval value with division
758  * @a: dividend
759  * @b: divisor
760  * @c: quotient
761  *
762  * c = a / b
763  *
764  * Returns non-zero if the value is changed, zero if not changed.
765  */
766 void snd_interval_div(const struct snd_interval *a, const struct snd_interval *b, struct snd_interval *c)
767 {
768 	unsigned int r;
769 	if (a->empty || b->empty) {
770 		snd_interval_none(c);
771 		return;
772 	}
773 	c->empty = 0;
774 	c->min = div32(a->min, b->max, &r);
775 	c->openmin = (r || a->openmin || b->openmax);
776 	if (b->min > 0) {
777 		c->max = div32(a->max, b->min, &r);
778 		if (r) {
779 			c->max++;
780 			c->openmax = 1;
781 		} else
782 			c->openmax = (a->openmax || b->openmin);
783 	} else {
784 		c->max = UINT_MAX;
785 		c->openmax = 0;
786 	}
787 	c->integer = 0;
788 }
789 
790 /**
791  * snd_interval_muldivk - refine the interval value
792  * @a: dividend 1
793  * @b: dividend 2
794  * @k: divisor (as integer)
795  * @c: result
796   *
797  * c = a * b / k
798  *
799  * Returns non-zero if the value is changed, zero if not changed.
800  */
801 void snd_interval_muldivk(const struct snd_interval *a, const struct snd_interval *b,
802 		      unsigned int k, struct snd_interval *c)
803 {
804 	unsigned int r;
805 	if (a->empty || b->empty) {
806 		snd_interval_none(c);
807 		return;
808 	}
809 	c->empty = 0;
810 	c->min = muldiv32(a->min, b->min, k, &r);
811 	c->openmin = (r || a->openmin || b->openmin);
812 	c->max = muldiv32(a->max, b->max, k, &r);
813 	if (r) {
814 		c->max++;
815 		c->openmax = 1;
816 	} else
817 		c->openmax = (a->openmax || b->openmax);
818 	c->integer = 0;
819 }
820 
821 /**
822  * snd_interval_mulkdiv - refine the interval value
823  * @a: dividend 1
824  * @k: dividend 2 (as integer)
825  * @b: divisor
826  * @c: result
827  *
828  * c = a * k / b
829  *
830  * Returns non-zero if the value is changed, zero if not changed.
831  */
832 void snd_interval_mulkdiv(const struct snd_interval *a, unsigned int k,
833 		      const struct snd_interval *b, struct snd_interval *c)
834 {
835 	unsigned int r;
836 	if (a->empty || b->empty) {
837 		snd_interval_none(c);
838 		return;
839 	}
840 	c->empty = 0;
841 	c->min = muldiv32(a->min, k, b->max, &r);
842 	c->openmin = (r || a->openmin || b->openmax);
843 	if (b->min > 0) {
844 		c->max = muldiv32(a->max, k, b->min, &r);
845 		if (r) {
846 			c->max++;
847 			c->openmax = 1;
848 		} else
849 			c->openmax = (a->openmax || b->openmin);
850 	} else {
851 		c->max = UINT_MAX;
852 		c->openmax = 0;
853 	}
854 	c->integer = 0;
855 }
856 
857 /* ---- */
858 
859 
860 /**
861  * snd_interval_ratnum - refine the interval value
862  * @i: interval to refine
863  * @rats_count: number of ratnum_t
864  * @rats: ratnum_t array
865  * @nump: pointer to store the resultant numerator
866  * @denp: pointer to store the resultant denominator
867  *
868  * Returns non-zero if the value is changed, zero if not changed.
869  */
870 int snd_interval_ratnum(struct snd_interval *i,
871 			unsigned int rats_count, struct snd_ratnum *rats,
872 			unsigned int *nump, unsigned int *denp)
873 {
874 	unsigned int best_num, best_den;
875 	int best_diff;
876 	unsigned int k;
877 	struct snd_interval t;
878 	int err;
879 	unsigned int result_num, result_den;
880 	int result_diff;
881 
882 	best_num = best_den = best_diff = 0;
883 	for (k = 0; k < rats_count; ++k) {
884 		unsigned int num = rats[k].num;
885 		unsigned int den;
886 		unsigned int q = i->min;
887 		int diff;
888 		if (q == 0)
889 			q = 1;
890 		den = div_up(num, q);
891 		if (den < rats[k].den_min)
892 			continue;
893 		if (den > rats[k].den_max)
894 			den = rats[k].den_max;
895 		else {
896 			unsigned int r;
897 			r = (den - rats[k].den_min) % rats[k].den_step;
898 			if (r != 0)
899 				den -= r;
900 		}
901 		diff = num - q * den;
902 		if (diff < 0)
903 			diff = -diff;
904 		if (best_num == 0 ||
905 		    diff * best_den < best_diff * den) {
906 			best_diff = diff;
907 			best_den = den;
908 			best_num = num;
909 		}
910 	}
911 	if (best_den == 0) {
912 		i->empty = 1;
913 		return -EINVAL;
914 	}
915 	t.min = div_down(best_num, best_den);
916 	t.openmin = !!(best_num % best_den);
917 
918 	result_num = best_num;
919 	result_diff = best_diff;
920 	result_den = best_den;
921 	best_num = best_den = best_diff = 0;
922 	for (k = 0; k < rats_count; ++k) {
923 		unsigned int num = rats[k].num;
924 		unsigned int den;
925 		unsigned int q = i->max;
926 		int diff;
927 		if (q == 0) {
928 			i->empty = 1;
929 			return -EINVAL;
930 		}
931 		den = div_down(num, q);
932 		if (den > rats[k].den_max)
933 			continue;
934 		if (den < rats[k].den_min)
935 			den = rats[k].den_min;
936 		else {
937 			unsigned int r;
938 			r = (den - rats[k].den_min) % rats[k].den_step;
939 			if (r != 0)
940 				den += rats[k].den_step - r;
941 		}
942 		diff = q * den - num;
943 		if (diff < 0)
944 			diff = -diff;
945 		if (best_num == 0 ||
946 		    diff * best_den < best_diff * den) {
947 			best_diff = diff;
948 			best_den = den;
949 			best_num = num;
950 		}
951 	}
952 	if (best_den == 0) {
953 		i->empty = 1;
954 		return -EINVAL;
955 	}
956 	t.max = div_up(best_num, best_den);
957 	t.openmax = !!(best_num % best_den);
958 	t.integer = 0;
959 	err = snd_interval_refine(i, &t);
960 	if (err < 0)
961 		return err;
962 
963 	if (snd_interval_single(i)) {
964 		if (best_diff * result_den < result_diff * best_den) {
965 			result_num = best_num;
966 			result_den = best_den;
967 		}
968 		if (nump)
969 			*nump = result_num;
970 		if (denp)
971 			*denp = result_den;
972 	}
973 	return err;
974 }
975 
976 EXPORT_SYMBOL(snd_interval_ratnum);
977 
978 /**
979  * snd_interval_ratden - refine the interval value
980  * @i: interval to refine
981  * @rats_count: number of struct ratden
982  * @rats: struct ratden array
983  * @nump: pointer to store the resultant numerator
984  * @denp: pointer to store the resultant denominator
985  *
986  * Returns non-zero if the value is changed, zero if not changed.
987  */
988 static int snd_interval_ratden(struct snd_interval *i,
989 			       unsigned int rats_count, struct snd_ratden *rats,
990 			       unsigned int *nump, unsigned int *denp)
991 {
992 	unsigned int best_num, best_diff, best_den;
993 	unsigned int k;
994 	struct snd_interval t;
995 	int err;
996 
997 	best_num = best_den = best_diff = 0;
998 	for (k = 0; k < rats_count; ++k) {
999 		unsigned int num;
1000 		unsigned int den = rats[k].den;
1001 		unsigned int q = i->min;
1002 		int diff;
1003 		num = mul(q, den);
1004 		if (num > rats[k].num_max)
1005 			continue;
1006 		if (num < rats[k].num_min)
1007 			num = rats[k].num_max;
1008 		else {
1009 			unsigned int r;
1010 			r = (num - rats[k].num_min) % rats[k].num_step;
1011 			if (r != 0)
1012 				num += rats[k].num_step - r;
1013 		}
1014 		diff = num - q * den;
1015 		if (best_num == 0 ||
1016 		    diff * best_den < best_diff * den) {
1017 			best_diff = diff;
1018 			best_den = den;
1019 			best_num = num;
1020 		}
1021 	}
1022 	if (best_den == 0) {
1023 		i->empty = 1;
1024 		return -EINVAL;
1025 	}
1026 	t.min = div_down(best_num, best_den);
1027 	t.openmin = !!(best_num % best_den);
1028 
1029 	best_num = best_den = best_diff = 0;
1030 	for (k = 0; k < rats_count; ++k) {
1031 		unsigned int num;
1032 		unsigned int den = rats[k].den;
1033 		unsigned int q = i->max;
1034 		int diff;
1035 		num = mul(q, den);
1036 		if (num < rats[k].num_min)
1037 			continue;
1038 		if (num > rats[k].num_max)
1039 			num = rats[k].num_max;
1040 		else {
1041 			unsigned int r;
1042 			r = (num - rats[k].num_min) % rats[k].num_step;
1043 			if (r != 0)
1044 				num -= r;
1045 		}
1046 		diff = q * den - num;
1047 		if (best_num == 0 ||
1048 		    diff * best_den < best_diff * den) {
1049 			best_diff = diff;
1050 			best_den = den;
1051 			best_num = num;
1052 		}
1053 	}
1054 	if (best_den == 0) {
1055 		i->empty = 1;
1056 		return -EINVAL;
1057 	}
1058 	t.max = div_up(best_num, best_den);
1059 	t.openmax = !!(best_num % best_den);
1060 	t.integer = 0;
1061 	err = snd_interval_refine(i, &t);
1062 	if (err < 0)
1063 		return err;
1064 
1065 	if (snd_interval_single(i)) {
1066 		if (nump)
1067 			*nump = best_num;
1068 		if (denp)
1069 			*denp = best_den;
1070 	}
1071 	return err;
1072 }
1073 
1074 /**
1075  * snd_interval_list - refine the interval value from the list
1076  * @i: the interval value to refine
1077  * @count: the number of elements in the list
1078  * @list: the value list
1079  * @mask: the bit-mask to evaluate
1080  *
1081  * Refines the interval value from the list.
1082  * When mask is non-zero, only the elements corresponding to bit 1 are
1083  * evaluated.
1084  *
1085  * Returns non-zero if the value is changed, zero if not changed.
1086  */
1087 int snd_interval_list(struct snd_interval *i, unsigned int count,
1088 		      const unsigned int *list, unsigned int mask)
1089 {
1090         unsigned int k;
1091 	struct snd_interval list_range;
1092 
1093 	if (!count) {
1094 		i->empty = 1;
1095 		return -EINVAL;
1096 	}
1097 	snd_interval_any(&list_range);
1098 	list_range.min = UINT_MAX;
1099 	list_range.max = 0;
1100         for (k = 0; k < count; k++) {
1101 		if (mask && !(mask & (1 << k)))
1102 			continue;
1103 		if (!snd_interval_test(i, list[k]))
1104 			continue;
1105 		list_range.min = min(list_range.min, list[k]);
1106 		list_range.max = max(list_range.max, list[k]);
1107         }
1108 	return snd_interval_refine(i, &list_range);
1109 }
1110 
1111 EXPORT_SYMBOL(snd_interval_list);
1112 
1113 static int snd_interval_step(struct snd_interval *i, unsigned int min, unsigned int step)
1114 {
1115 	unsigned int n;
1116 	int changed = 0;
1117 	n = (i->min - min) % step;
1118 	if (n != 0 || i->openmin) {
1119 		i->min += step - n;
1120 		changed = 1;
1121 	}
1122 	n = (i->max - min) % step;
1123 	if (n != 0 || i->openmax) {
1124 		i->max -= n;
1125 		changed = 1;
1126 	}
1127 	if (snd_interval_checkempty(i)) {
1128 		i->empty = 1;
1129 		return -EINVAL;
1130 	}
1131 	return changed;
1132 }
1133 
1134 /* Info constraints helpers */
1135 
1136 /**
1137  * snd_pcm_hw_rule_add - add the hw-constraint rule
1138  * @runtime: the pcm runtime instance
1139  * @cond: condition bits
1140  * @var: the variable to evaluate
1141  * @func: the evaluation function
1142  * @private: the private data pointer passed to function
1143  * @dep: the dependent variables
1144  *
1145  * Returns zero if successful, or a negative error code on failure.
1146  */
1147 int snd_pcm_hw_rule_add(struct snd_pcm_runtime *runtime, unsigned int cond,
1148 			int var,
1149 			snd_pcm_hw_rule_func_t func, void *private,
1150 			int dep, ...)
1151 {
1152 	struct snd_pcm_hw_constraints *constrs = &runtime->hw_constraints;
1153 	struct snd_pcm_hw_rule *c;
1154 	unsigned int k;
1155 	va_list args;
1156 	va_start(args, dep);
1157 	if (constrs->rules_num >= constrs->rules_all) {
1158 		struct snd_pcm_hw_rule *new;
1159 		unsigned int new_rules = constrs->rules_all + 16;
1160 		new = kcalloc(new_rules, sizeof(*c), GFP_KERNEL);
1161 		if (!new) {
1162 			va_end(args);
1163 			return -ENOMEM;
1164 		}
1165 		if (constrs->rules) {
1166 			memcpy(new, constrs->rules,
1167 			       constrs->rules_num * sizeof(*c));
1168 			kfree(constrs->rules);
1169 		}
1170 		constrs->rules = new;
1171 		constrs->rules_all = new_rules;
1172 	}
1173 	c = &constrs->rules[constrs->rules_num];
1174 	c->cond = cond;
1175 	c->func = func;
1176 	c->var = var;
1177 	c->private = private;
1178 	k = 0;
1179 	while (1) {
1180 		if (snd_BUG_ON(k >= ARRAY_SIZE(c->deps))) {
1181 			va_end(args);
1182 			return -EINVAL;
1183 		}
1184 		c->deps[k++] = dep;
1185 		if (dep < 0)
1186 			break;
1187 		dep = va_arg(args, int);
1188 	}
1189 	constrs->rules_num++;
1190 	va_end(args);
1191 	return 0;
1192 }
1193 
1194 EXPORT_SYMBOL(snd_pcm_hw_rule_add);
1195 
1196 /**
1197  * snd_pcm_hw_constraint_mask - apply the given bitmap mask constraint
1198  * @runtime: PCM runtime instance
1199  * @var: hw_params variable to apply the mask
1200  * @mask: the bitmap mask
1201  *
1202  * Apply the constraint of the given bitmap mask to a 32-bit mask parameter.
1203  */
1204 int snd_pcm_hw_constraint_mask(struct snd_pcm_runtime *runtime, snd_pcm_hw_param_t var,
1205 			       u_int32_t mask)
1206 {
1207 	struct snd_pcm_hw_constraints *constrs = &runtime->hw_constraints;
1208 	struct snd_mask *maskp = constrs_mask(constrs, var);
1209 	*maskp->bits &= mask;
1210 	memset(maskp->bits + 1, 0, (SNDRV_MASK_MAX-32) / 8); /* clear rest */
1211 	if (*maskp->bits == 0)
1212 		return -EINVAL;
1213 	return 0;
1214 }
1215 
1216 /**
1217  * snd_pcm_hw_constraint_mask64 - apply the given bitmap mask constraint
1218  * @runtime: PCM runtime instance
1219  * @var: hw_params variable to apply the mask
1220  * @mask: the 64bit bitmap mask
1221  *
1222  * Apply the constraint of the given bitmap mask to a 64-bit mask parameter.
1223  */
1224 int snd_pcm_hw_constraint_mask64(struct snd_pcm_runtime *runtime, snd_pcm_hw_param_t var,
1225 				 u_int64_t mask)
1226 {
1227 	struct snd_pcm_hw_constraints *constrs = &runtime->hw_constraints;
1228 	struct snd_mask *maskp = constrs_mask(constrs, var);
1229 	maskp->bits[0] &= (u_int32_t)mask;
1230 	maskp->bits[1] &= (u_int32_t)(mask >> 32);
1231 	memset(maskp->bits + 2, 0, (SNDRV_MASK_MAX-64) / 8); /* clear rest */
1232 	if (! maskp->bits[0] && ! maskp->bits[1])
1233 		return -EINVAL;
1234 	return 0;
1235 }
1236 
1237 /**
1238  * snd_pcm_hw_constraint_integer - apply an integer constraint to an interval
1239  * @runtime: PCM runtime instance
1240  * @var: hw_params variable to apply the integer constraint
1241  *
1242  * Apply the constraint of integer to an interval parameter.
1243  */
1244 int snd_pcm_hw_constraint_integer(struct snd_pcm_runtime *runtime, snd_pcm_hw_param_t var)
1245 {
1246 	struct snd_pcm_hw_constraints *constrs = &runtime->hw_constraints;
1247 	return snd_interval_setinteger(constrs_interval(constrs, var));
1248 }
1249 
1250 EXPORT_SYMBOL(snd_pcm_hw_constraint_integer);
1251 
1252 /**
1253  * snd_pcm_hw_constraint_minmax - apply a min/max range constraint to an interval
1254  * @runtime: PCM runtime instance
1255  * @var: hw_params variable to apply the range
1256  * @min: the minimal value
1257  * @max: the maximal value
1258  *
1259  * Apply the min/max range constraint to an interval parameter.
1260  */
1261 int snd_pcm_hw_constraint_minmax(struct snd_pcm_runtime *runtime, snd_pcm_hw_param_t var,
1262 				 unsigned int min, unsigned int max)
1263 {
1264 	struct snd_pcm_hw_constraints *constrs = &runtime->hw_constraints;
1265 	struct snd_interval t;
1266 	t.min = min;
1267 	t.max = max;
1268 	t.openmin = t.openmax = 0;
1269 	t.integer = 0;
1270 	return snd_interval_refine(constrs_interval(constrs, var), &t);
1271 }
1272 
1273 EXPORT_SYMBOL(snd_pcm_hw_constraint_minmax);
1274 
1275 static int snd_pcm_hw_rule_list(struct snd_pcm_hw_params *params,
1276 				struct snd_pcm_hw_rule *rule)
1277 {
1278 	struct snd_pcm_hw_constraint_list *list = rule->private;
1279 	return snd_interval_list(hw_param_interval(params, rule->var), list->count, list->list, list->mask);
1280 }
1281 
1282 
1283 /**
1284  * snd_pcm_hw_constraint_list - apply a list of constraints to a parameter
1285  * @runtime: PCM runtime instance
1286  * @cond: condition bits
1287  * @var: hw_params variable to apply the list constraint
1288  * @l: list
1289  *
1290  * Apply the list of constraints to an interval parameter.
1291  */
1292 int snd_pcm_hw_constraint_list(struct snd_pcm_runtime *runtime,
1293 			       unsigned int cond,
1294 			       snd_pcm_hw_param_t var,
1295 			       const struct snd_pcm_hw_constraint_list *l)
1296 {
1297 	return snd_pcm_hw_rule_add(runtime, cond, var,
1298 				   snd_pcm_hw_rule_list, (void *)l,
1299 				   var, -1);
1300 }
1301 
1302 EXPORT_SYMBOL(snd_pcm_hw_constraint_list);
1303 
1304 static int snd_pcm_hw_rule_ratnums(struct snd_pcm_hw_params *params,
1305 				   struct snd_pcm_hw_rule *rule)
1306 {
1307 	struct snd_pcm_hw_constraint_ratnums *r = rule->private;
1308 	unsigned int num = 0, den = 0;
1309 	int err;
1310 	err = snd_interval_ratnum(hw_param_interval(params, rule->var),
1311 				  r->nrats, r->rats, &num, &den);
1312 	if (err >= 0 && den && rule->var == SNDRV_PCM_HW_PARAM_RATE) {
1313 		params->rate_num = num;
1314 		params->rate_den = den;
1315 	}
1316 	return err;
1317 }
1318 
1319 /**
1320  * snd_pcm_hw_constraint_ratnums - apply ratnums constraint to a parameter
1321  * @runtime: PCM runtime instance
1322  * @cond: condition bits
1323  * @var: hw_params variable to apply the ratnums constraint
1324  * @r: struct snd_ratnums constriants
1325  */
1326 int snd_pcm_hw_constraint_ratnums(struct snd_pcm_runtime *runtime,
1327 				  unsigned int cond,
1328 				  snd_pcm_hw_param_t var,
1329 				  struct snd_pcm_hw_constraint_ratnums *r)
1330 {
1331 	return snd_pcm_hw_rule_add(runtime, cond, var,
1332 				   snd_pcm_hw_rule_ratnums, r,
1333 				   var, -1);
1334 }
1335 
1336 EXPORT_SYMBOL(snd_pcm_hw_constraint_ratnums);
1337 
1338 static int snd_pcm_hw_rule_ratdens(struct snd_pcm_hw_params *params,
1339 				   struct snd_pcm_hw_rule *rule)
1340 {
1341 	struct snd_pcm_hw_constraint_ratdens *r = rule->private;
1342 	unsigned int num = 0, den = 0;
1343 	int err = snd_interval_ratden(hw_param_interval(params, rule->var),
1344 				  r->nrats, r->rats, &num, &den);
1345 	if (err >= 0 && den && rule->var == SNDRV_PCM_HW_PARAM_RATE) {
1346 		params->rate_num = num;
1347 		params->rate_den = den;
1348 	}
1349 	return err;
1350 }
1351 
1352 /**
1353  * snd_pcm_hw_constraint_ratdens - apply ratdens constraint to a parameter
1354  * @runtime: PCM runtime instance
1355  * @cond: condition bits
1356  * @var: hw_params variable to apply the ratdens constraint
1357  * @r: struct snd_ratdens constriants
1358  */
1359 int snd_pcm_hw_constraint_ratdens(struct snd_pcm_runtime *runtime,
1360 				  unsigned int cond,
1361 				  snd_pcm_hw_param_t var,
1362 				  struct snd_pcm_hw_constraint_ratdens *r)
1363 {
1364 	return snd_pcm_hw_rule_add(runtime, cond, var,
1365 				   snd_pcm_hw_rule_ratdens, r,
1366 				   var, -1);
1367 }
1368 
1369 EXPORT_SYMBOL(snd_pcm_hw_constraint_ratdens);
1370 
1371 static int snd_pcm_hw_rule_msbits(struct snd_pcm_hw_params *params,
1372 				  struct snd_pcm_hw_rule *rule)
1373 {
1374 	unsigned int l = (unsigned long) rule->private;
1375 	int width = l & 0xffff;
1376 	unsigned int msbits = l >> 16;
1377 	struct snd_interval *i = hw_param_interval(params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS);
1378 	if (snd_interval_single(i) && snd_interval_value(i) == width)
1379 		params->msbits = msbits;
1380 	return 0;
1381 }
1382 
1383 /**
1384  * snd_pcm_hw_constraint_msbits - add a hw constraint msbits rule
1385  * @runtime: PCM runtime instance
1386  * @cond: condition bits
1387  * @width: sample bits width
1388  * @msbits: msbits width
1389  */
1390 int snd_pcm_hw_constraint_msbits(struct snd_pcm_runtime *runtime,
1391 				 unsigned int cond,
1392 				 unsigned int width,
1393 				 unsigned int msbits)
1394 {
1395 	unsigned long l = (msbits << 16) | width;
1396 	return snd_pcm_hw_rule_add(runtime, cond, -1,
1397 				    snd_pcm_hw_rule_msbits,
1398 				    (void*) l,
1399 				    SNDRV_PCM_HW_PARAM_SAMPLE_BITS, -1);
1400 }
1401 
1402 EXPORT_SYMBOL(snd_pcm_hw_constraint_msbits);
1403 
1404 static int snd_pcm_hw_rule_step(struct snd_pcm_hw_params *params,
1405 				struct snd_pcm_hw_rule *rule)
1406 {
1407 	unsigned long step = (unsigned long) rule->private;
1408 	return snd_interval_step(hw_param_interval(params, rule->var), 0, step);
1409 }
1410 
1411 /**
1412  * snd_pcm_hw_constraint_step - add a hw constraint step rule
1413  * @runtime: PCM runtime instance
1414  * @cond: condition bits
1415  * @var: hw_params variable to apply the step constraint
1416  * @step: step size
1417  */
1418 int snd_pcm_hw_constraint_step(struct snd_pcm_runtime *runtime,
1419 			       unsigned int cond,
1420 			       snd_pcm_hw_param_t var,
1421 			       unsigned long step)
1422 {
1423 	return snd_pcm_hw_rule_add(runtime, cond, var,
1424 				   snd_pcm_hw_rule_step, (void *) step,
1425 				   var, -1);
1426 }
1427 
1428 EXPORT_SYMBOL(snd_pcm_hw_constraint_step);
1429 
1430 static int snd_pcm_hw_rule_pow2(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule)
1431 {
1432 	static unsigned int pow2_sizes[] = {
1433 		1<<0, 1<<1, 1<<2, 1<<3, 1<<4, 1<<5, 1<<6, 1<<7,
1434 		1<<8, 1<<9, 1<<10, 1<<11, 1<<12, 1<<13, 1<<14, 1<<15,
1435 		1<<16, 1<<17, 1<<18, 1<<19, 1<<20, 1<<21, 1<<22, 1<<23,
1436 		1<<24, 1<<25, 1<<26, 1<<27, 1<<28, 1<<29, 1<<30
1437 	};
1438 	return snd_interval_list(hw_param_interval(params, rule->var),
1439 				 ARRAY_SIZE(pow2_sizes), pow2_sizes, 0);
1440 }
1441 
1442 /**
1443  * snd_pcm_hw_constraint_pow2 - add a hw constraint power-of-2 rule
1444  * @runtime: PCM runtime instance
1445  * @cond: condition bits
1446  * @var: hw_params variable to apply the power-of-2 constraint
1447  */
1448 int snd_pcm_hw_constraint_pow2(struct snd_pcm_runtime *runtime,
1449 			       unsigned int cond,
1450 			       snd_pcm_hw_param_t var)
1451 {
1452 	return snd_pcm_hw_rule_add(runtime, cond, var,
1453 				   snd_pcm_hw_rule_pow2, NULL,
1454 				   var, -1);
1455 }
1456 
1457 EXPORT_SYMBOL(snd_pcm_hw_constraint_pow2);
1458 
1459 static int snd_pcm_hw_rule_noresample_func(struct snd_pcm_hw_params *params,
1460 					   struct snd_pcm_hw_rule *rule)
1461 {
1462 	unsigned int base_rate = (unsigned int)(uintptr_t)rule->private;
1463 	struct snd_interval *rate;
1464 
1465 	rate = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
1466 	return snd_interval_list(rate, 1, &base_rate, 0);
1467 }
1468 
1469 /**
1470  * snd_pcm_hw_rule_noresample - add a rule to allow disabling hw resampling
1471  * @runtime: PCM runtime instance
1472  * @base_rate: the rate at which the hardware does not resample
1473  */
1474 int snd_pcm_hw_rule_noresample(struct snd_pcm_runtime *runtime,
1475 			       unsigned int base_rate)
1476 {
1477 	return snd_pcm_hw_rule_add(runtime, SNDRV_PCM_HW_PARAMS_NORESAMPLE,
1478 				   SNDRV_PCM_HW_PARAM_RATE,
1479 				   snd_pcm_hw_rule_noresample_func,
1480 				   (void *)(uintptr_t)base_rate,
1481 				   SNDRV_PCM_HW_PARAM_RATE, -1);
1482 }
1483 EXPORT_SYMBOL(snd_pcm_hw_rule_noresample);
1484 
1485 static void _snd_pcm_hw_param_any(struct snd_pcm_hw_params *params,
1486 				  snd_pcm_hw_param_t var)
1487 {
1488 	if (hw_is_mask(var)) {
1489 		snd_mask_any(hw_param_mask(params, var));
1490 		params->cmask |= 1 << var;
1491 		params->rmask |= 1 << var;
1492 		return;
1493 	}
1494 	if (hw_is_interval(var)) {
1495 		snd_interval_any(hw_param_interval(params, var));
1496 		params->cmask |= 1 << var;
1497 		params->rmask |= 1 << var;
1498 		return;
1499 	}
1500 	snd_BUG();
1501 }
1502 
1503 void _snd_pcm_hw_params_any(struct snd_pcm_hw_params *params)
1504 {
1505 	unsigned int k;
1506 	memset(params, 0, sizeof(*params));
1507 	for (k = SNDRV_PCM_HW_PARAM_FIRST_MASK; k <= SNDRV_PCM_HW_PARAM_LAST_MASK; k++)
1508 		_snd_pcm_hw_param_any(params, k);
1509 	for (k = SNDRV_PCM_HW_PARAM_FIRST_INTERVAL; k <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; k++)
1510 		_snd_pcm_hw_param_any(params, k);
1511 	params->info = ~0U;
1512 }
1513 
1514 EXPORT_SYMBOL(_snd_pcm_hw_params_any);
1515 
1516 /**
1517  * snd_pcm_hw_param_value - return @params field @var value
1518  * @params: the hw_params instance
1519  * @var: parameter to retrieve
1520  * @dir: pointer to the direction (-1,0,1) or %NULL
1521  *
1522  * Return the value for field @var if it's fixed in configuration space
1523  * defined by @params. Return -%EINVAL otherwise.
1524  */
1525 int snd_pcm_hw_param_value(const struct snd_pcm_hw_params *params,
1526 			   snd_pcm_hw_param_t var, int *dir)
1527 {
1528 	if (hw_is_mask(var)) {
1529 		const struct snd_mask *mask = hw_param_mask_c(params, var);
1530 		if (!snd_mask_single(mask))
1531 			return -EINVAL;
1532 		if (dir)
1533 			*dir = 0;
1534 		return snd_mask_value(mask);
1535 	}
1536 	if (hw_is_interval(var)) {
1537 		const struct snd_interval *i = hw_param_interval_c(params, var);
1538 		if (!snd_interval_single(i))
1539 			return -EINVAL;
1540 		if (dir)
1541 			*dir = i->openmin;
1542 		return snd_interval_value(i);
1543 	}
1544 	return -EINVAL;
1545 }
1546 
1547 EXPORT_SYMBOL(snd_pcm_hw_param_value);
1548 
1549 void _snd_pcm_hw_param_setempty(struct snd_pcm_hw_params *params,
1550 				snd_pcm_hw_param_t var)
1551 {
1552 	if (hw_is_mask(var)) {
1553 		snd_mask_none(hw_param_mask(params, var));
1554 		params->cmask |= 1 << var;
1555 		params->rmask |= 1 << var;
1556 	} else if (hw_is_interval(var)) {
1557 		snd_interval_none(hw_param_interval(params, var));
1558 		params->cmask |= 1 << var;
1559 		params->rmask |= 1 << var;
1560 	} else {
1561 		snd_BUG();
1562 	}
1563 }
1564 
1565 EXPORT_SYMBOL(_snd_pcm_hw_param_setempty);
1566 
1567 static int _snd_pcm_hw_param_first(struct snd_pcm_hw_params *params,
1568 				   snd_pcm_hw_param_t var)
1569 {
1570 	int changed;
1571 	if (hw_is_mask(var))
1572 		changed = snd_mask_refine_first(hw_param_mask(params, var));
1573 	else if (hw_is_interval(var))
1574 		changed = snd_interval_refine_first(hw_param_interval(params, var));
1575 	else
1576 		return -EINVAL;
1577 	if (changed) {
1578 		params->cmask |= 1 << var;
1579 		params->rmask |= 1 << var;
1580 	}
1581 	return changed;
1582 }
1583 
1584 
1585 /**
1586  * snd_pcm_hw_param_first - refine config space and return minimum value
1587  * @pcm: PCM instance
1588  * @params: the hw_params instance
1589  * @var: parameter to retrieve
1590  * @dir: pointer to the direction (-1,0,1) or %NULL
1591  *
1592  * Inside configuration space defined by @params remove from @var all
1593  * values > minimum. Reduce configuration space accordingly.
1594  * Return the minimum.
1595  */
1596 int snd_pcm_hw_param_first(struct snd_pcm_substream *pcm,
1597 			   struct snd_pcm_hw_params *params,
1598 			   snd_pcm_hw_param_t var, int *dir)
1599 {
1600 	int changed = _snd_pcm_hw_param_first(params, var);
1601 	if (changed < 0)
1602 		return changed;
1603 	if (params->rmask) {
1604 		int err = snd_pcm_hw_refine(pcm, params);
1605 		if (snd_BUG_ON(err < 0))
1606 			return err;
1607 	}
1608 	return snd_pcm_hw_param_value(params, var, dir);
1609 }
1610 
1611 EXPORT_SYMBOL(snd_pcm_hw_param_first);
1612 
1613 static int _snd_pcm_hw_param_last(struct snd_pcm_hw_params *params,
1614 				  snd_pcm_hw_param_t var)
1615 {
1616 	int changed;
1617 	if (hw_is_mask(var))
1618 		changed = snd_mask_refine_last(hw_param_mask(params, var));
1619 	else if (hw_is_interval(var))
1620 		changed = snd_interval_refine_last(hw_param_interval(params, var));
1621 	else
1622 		return -EINVAL;
1623 	if (changed) {
1624 		params->cmask |= 1 << var;
1625 		params->rmask |= 1 << var;
1626 	}
1627 	return changed;
1628 }
1629 
1630 
1631 /**
1632  * snd_pcm_hw_param_last - refine config space and return maximum value
1633  * @pcm: PCM instance
1634  * @params: the hw_params instance
1635  * @var: parameter to retrieve
1636  * @dir: pointer to the direction (-1,0,1) or %NULL
1637  *
1638  * Inside configuration space defined by @params remove from @var all
1639  * values < maximum. Reduce configuration space accordingly.
1640  * Return the maximum.
1641  */
1642 int snd_pcm_hw_param_last(struct snd_pcm_substream *pcm,
1643 			  struct snd_pcm_hw_params *params,
1644 			  snd_pcm_hw_param_t var, int *dir)
1645 {
1646 	int changed = _snd_pcm_hw_param_last(params, var);
1647 	if (changed < 0)
1648 		return changed;
1649 	if (params->rmask) {
1650 		int err = snd_pcm_hw_refine(pcm, params);
1651 		if (snd_BUG_ON(err < 0))
1652 			return err;
1653 	}
1654 	return snd_pcm_hw_param_value(params, var, dir);
1655 }
1656 
1657 EXPORT_SYMBOL(snd_pcm_hw_param_last);
1658 
1659 /**
1660  * snd_pcm_hw_param_choose - choose a configuration defined by @params
1661  * @pcm: PCM instance
1662  * @params: the hw_params instance
1663  *
1664  * Choose one configuration from configuration space defined by @params.
1665  * The configuration chosen is that obtained fixing in this order:
1666  * first access, first format, first subformat, min channels,
1667  * min rate, min period time, max buffer size, min tick time
1668  */
1669 int snd_pcm_hw_params_choose(struct snd_pcm_substream *pcm,
1670 			     struct snd_pcm_hw_params *params)
1671 {
1672 	static int vars[] = {
1673 		SNDRV_PCM_HW_PARAM_ACCESS,
1674 		SNDRV_PCM_HW_PARAM_FORMAT,
1675 		SNDRV_PCM_HW_PARAM_SUBFORMAT,
1676 		SNDRV_PCM_HW_PARAM_CHANNELS,
1677 		SNDRV_PCM_HW_PARAM_RATE,
1678 		SNDRV_PCM_HW_PARAM_PERIOD_TIME,
1679 		SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
1680 		SNDRV_PCM_HW_PARAM_TICK_TIME,
1681 		-1
1682 	};
1683 	int err, *v;
1684 
1685 	for (v = vars; *v != -1; v++) {
1686 		if (*v != SNDRV_PCM_HW_PARAM_BUFFER_SIZE)
1687 			err = snd_pcm_hw_param_first(pcm, params, *v, NULL);
1688 		else
1689 			err = snd_pcm_hw_param_last(pcm, params, *v, NULL);
1690 		if (snd_BUG_ON(err < 0))
1691 			return err;
1692 	}
1693 	return 0;
1694 }
1695 
1696 static int snd_pcm_lib_ioctl_reset(struct snd_pcm_substream *substream,
1697 				   void *arg)
1698 {
1699 	struct snd_pcm_runtime *runtime = substream->runtime;
1700 	unsigned long flags;
1701 	snd_pcm_stream_lock_irqsave(substream, flags);
1702 	if (snd_pcm_running(substream) &&
1703 	    snd_pcm_update_hw_ptr(substream) >= 0)
1704 		runtime->status->hw_ptr %= runtime->buffer_size;
1705 	else {
1706 		runtime->status->hw_ptr = 0;
1707 		runtime->hw_ptr_wrap = 0;
1708 	}
1709 	snd_pcm_stream_unlock_irqrestore(substream, flags);
1710 	return 0;
1711 }
1712 
1713 static int snd_pcm_lib_ioctl_channel_info(struct snd_pcm_substream *substream,
1714 					  void *arg)
1715 {
1716 	struct snd_pcm_channel_info *info = arg;
1717 	struct snd_pcm_runtime *runtime = substream->runtime;
1718 	int width;
1719 	if (!(runtime->info & SNDRV_PCM_INFO_MMAP)) {
1720 		info->offset = -1;
1721 		return 0;
1722 	}
1723 	width = snd_pcm_format_physical_width(runtime->format);
1724 	if (width < 0)
1725 		return width;
1726 	info->offset = 0;
1727 	switch (runtime->access) {
1728 	case SNDRV_PCM_ACCESS_MMAP_INTERLEAVED:
1729 	case SNDRV_PCM_ACCESS_RW_INTERLEAVED:
1730 		info->first = info->channel * width;
1731 		info->step = runtime->channels * width;
1732 		break;
1733 	case SNDRV_PCM_ACCESS_MMAP_NONINTERLEAVED:
1734 	case SNDRV_PCM_ACCESS_RW_NONINTERLEAVED:
1735 	{
1736 		size_t size = runtime->dma_bytes / runtime->channels;
1737 		info->first = info->channel * size * 8;
1738 		info->step = width;
1739 		break;
1740 	}
1741 	default:
1742 		snd_BUG();
1743 		break;
1744 	}
1745 	return 0;
1746 }
1747 
1748 static int snd_pcm_lib_ioctl_fifo_size(struct snd_pcm_substream *substream,
1749 				       void *arg)
1750 {
1751 	struct snd_pcm_hw_params *params = arg;
1752 	snd_pcm_format_t format;
1753 	int channels, width;
1754 
1755 	params->fifo_size = substream->runtime->hw.fifo_size;
1756 	if (!(substream->runtime->hw.info & SNDRV_PCM_INFO_FIFO_IN_FRAMES)) {
1757 		format = params_format(params);
1758 		channels = params_channels(params);
1759 		width = snd_pcm_format_physical_width(format);
1760 		params->fifo_size /= width * channels;
1761 	}
1762 	return 0;
1763 }
1764 
1765 /**
1766  * snd_pcm_lib_ioctl - a generic PCM ioctl callback
1767  * @substream: the pcm substream instance
1768  * @cmd: ioctl command
1769  * @arg: ioctl argument
1770  *
1771  * Processes the generic ioctl commands for PCM.
1772  * Can be passed as the ioctl callback for PCM ops.
1773  *
1774  * Returns zero if successful, or a negative error code on failure.
1775  */
1776 int snd_pcm_lib_ioctl(struct snd_pcm_substream *substream,
1777 		      unsigned int cmd, void *arg)
1778 {
1779 	switch (cmd) {
1780 	case SNDRV_PCM_IOCTL1_INFO:
1781 		return 0;
1782 	case SNDRV_PCM_IOCTL1_RESET:
1783 		return snd_pcm_lib_ioctl_reset(substream, arg);
1784 	case SNDRV_PCM_IOCTL1_CHANNEL_INFO:
1785 		return snd_pcm_lib_ioctl_channel_info(substream, arg);
1786 	case SNDRV_PCM_IOCTL1_FIFO_SIZE:
1787 		return snd_pcm_lib_ioctl_fifo_size(substream, arg);
1788 	}
1789 	return -ENXIO;
1790 }
1791 
1792 EXPORT_SYMBOL(snd_pcm_lib_ioctl);
1793 
1794 /**
1795  * snd_pcm_period_elapsed - update the pcm status for the next period
1796  * @substream: the pcm substream instance
1797  *
1798  * This function is called from the interrupt handler when the
1799  * PCM has processed the period size.  It will update the current
1800  * pointer, wake up sleepers, etc.
1801  *
1802  * Even if more than one periods have elapsed since the last call, you
1803  * have to call this only once.
1804  */
1805 void snd_pcm_period_elapsed(struct snd_pcm_substream *substream)
1806 {
1807 	struct snd_pcm_runtime *runtime;
1808 	unsigned long flags;
1809 
1810 	if (PCM_RUNTIME_CHECK(substream))
1811 		return;
1812 	runtime = substream->runtime;
1813 
1814 	if (runtime->transfer_ack_begin)
1815 		runtime->transfer_ack_begin(substream);
1816 
1817 	snd_pcm_stream_lock_irqsave(substream, flags);
1818 	if (!snd_pcm_running(substream) ||
1819 	    snd_pcm_update_hw_ptr0(substream, 1) < 0)
1820 		goto _end;
1821 
1822 	if (substream->timer_running)
1823 		snd_timer_interrupt(substream->timer, 1);
1824  _end:
1825 	snd_pcm_stream_unlock_irqrestore(substream, flags);
1826 	if (runtime->transfer_ack_end)
1827 		runtime->transfer_ack_end(substream);
1828 	kill_fasync(&runtime->fasync, SIGIO, POLL_IN);
1829 }
1830 
1831 EXPORT_SYMBOL(snd_pcm_period_elapsed);
1832 
1833 /*
1834  * Wait until avail_min data becomes available
1835  * Returns a negative error code if any error occurs during operation.
1836  * The available space is stored on availp.  When err = 0 and avail = 0
1837  * on the capture stream, it indicates the stream is in DRAINING state.
1838  */
1839 static int wait_for_avail(struct snd_pcm_substream *substream,
1840 			      snd_pcm_uframes_t *availp)
1841 {
1842 	struct snd_pcm_runtime *runtime = substream->runtime;
1843 	int is_playback = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
1844 	wait_queue_t wait;
1845 	int err = 0;
1846 	snd_pcm_uframes_t avail = 0;
1847 	long wait_time, tout;
1848 
1849 	init_waitqueue_entry(&wait, current);
1850 	set_current_state(TASK_INTERRUPTIBLE);
1851 	add_wait_queue(&runtime->tsleep, &wait);
1852 
1853 	if (runtime->no_period_wakeup)
1854 		wait_time = MAX_SCHEDULE_TIMEOUT;
1855 	else {
1856 		wait_time = 10;
1857 		if (runtime->rate) {
1858 			long t = runtime->period_size * 2 / runtime->rate;
1859 			wait_time = max(t, wait_time);
1860 		}
1861 		wait_time = msecs_to_jiffies(wait_time * 1000);
1862 	}
1863 
1864 	for (;;) {
1865 		if (signal_pending(current)) {
1866 			err = -ERESTARTSYS;
1867 			break;
1868 		}
1869 
1870 		/*
1871 		 * We need to check if space became available already
1872 		 * (and thus the wakeup happened already) first to close
1873 		 * the race of space already having become available.
1874 		 * This check must happen after been added to the waitqueue
1875 		 * and having current state be INTERRUPTIBLE.
1876 		 */
1877 		if (is_playback)
1878 			avail = snd_pcm_playback_avail(runtime);
1879 		else
1880 			avail = snd_pcm_capture_avail(runtime);
1881 		if (avail >= runtime->twake)
1882 			break;
1883 		snd_pcm_stream_unlock_irq(substream);
1884 
1885 		tout = schedule_timeout(wait_time);
1886 
1887 		snd_pcm_stream_lock_irq(substream);
1888 		set_current_state(TASK_INTERRUPTIBLE);
1889 		switch (runtime->status->state) {
1890 		case SNDRV_PCM_STATE_SUSPENDED:
1891 			err = -ESTRPIPE;
1892 			goto _endloop;
1893 		case SNDRV_PCM_STATE_XRUN:
1894 			err = -EPIPE;
1895 			goto _endloop;
1896 		case SNDRV_PCM_STATE_DRAINING:
1897 			if (is_playback)
1898 				err = -EPIPE;
1899 			else
1900 				avail = 0; /* indicate draining */
1901 			goto _endloop;
1902 		case SNDRV_PCM_STATE_OPEN:
1903 		case SNDRV_PCM_STATE_SETUP:
1904 		case SNDRV_PCM_STATE_DISCONNECTED:
1905 			err = -EBADFD;
1906 			goto _endloop;
1907 		}
1908 		if (!tout) {
1909 			snd_printd("%s write error (DMA or IRQ trouble?)\n",
1910 				   is_playback ? "playback" : "capture");
1911 			err = -EIO;
1912 			break;
1913 		}
1914 	}
1915  _endloop:
1916 	set_current_state(TASK_RUNNING);
1917 	remove_wait_queue(&runtime->tsleep, &wait);
1918 	*availp = avail;
1919 	return err;
1920 }
1921 
1922 static int snd_pcm_lib_write_transfer(struct snd_pcm_substream *substream,
1923 				      unsigned int hwoff,
1924 				      unsigned long data, unsigned int off,
1925 				      snd_pcm_uframes_t frames)
1926 {
1927 	struct snd_pcm_runtime *runtime = substream->runtime;
1928 	int err;
1929 	char __user *buf = (char __user *) data + frames_to_bytes(runtime, off);
1930 	if (substream->ops->copy) {
1931 		if ((err = substream->ops->copy(substream, -1, hwoff, buf, frames)) < 0)
1932 			return err;
1933 	} else {
1934 		char *hwbuf = runtime->dma_area + frames_to_bytes(runtime, hwoff);
1935 		if (copy_from_user(hwbuf, buf, frames_to_bytes(runtime, frames)))
1936 			return -EFAULT;
1937 	}
1938 	return 0;
1939 }
1940 
1941 typedef int (*transfer_f)(struct snd_pcm_substream *substream, unsigned int hwoff,
1942 			  unsigned long data, unsigned int off,
1943 			  snd_pcm_uframes_t size);
1944 
1945 static snd_pcm_sframes_t snd_pcm_lib_write1(struct snd_pcm_substream *substream,
1946 					    unsigned long data,
1947 					    snd_pcm_uframes_t size,
1948 					    int nonblock,
1949 					    transfer_f transfer)
1950 {
1951 	struct snd_pcm_runtime *runtime = substream->runtime;
1952 	snd_pcm_uframes_t xfer = 0;
1953 	snd_pcm_uframes_t offset = 0;
1954 	snd_pcm_uframes_t avail;
1955 	int err = 0;
1956 
1957 	if (size == 0)
1958 		return 0;
1959 
1960 	snd_pcm_stream_lock_irq(substream);
1961 	switch (runtime->status->state) {
1962 	case SNDRV_PCM_STATE_PREPARED:
1963 	case SNDRV_PCM_STATE_RUNNING:
1964 	case SNDRV_PCM_STATE_PAUSED:
1965 		break;
1966 	case SNDRV_PCM_STATE_XRUN:
1967 		err = -EPIPE;
1968 		goto _end_unlock;
1969 	case SNDRV_PCM_STATE_SUSPENDED:
1970 		err = -ESTRPIPE;
1971 		goto _end_unlock;
1972 	default:
1973 		err = -EBADFD;
1974 		goto _end_unlock;
1975 	}
1976 
1977 	runtime->twake = runtime->control->avail_min ? : 1;
1978 	if (runtime->status->state == SNDRV_PCM_STATE_RUNNING)
1979 		snd_pcm_update_hw_ptr(substream);
1980 	avail = snd_pcm_playback_avail(runtime);
1981 	while (size > 0) {
1982 		snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
1983 		snd_pcm_uframes_t cont;
1984 		if (!avail) {
1985 			if (nonblock) {
1986 				err = -EAGAIN;
1987 				goto _end_unlock;
1988 			}
1989 			runtime->twake = min_t(snd_pcm_uframes_t, size,
1990 					runtime->control->avail_min ? : 1);
1991 			err = wait_for_avail(substream, &avail);
1992 			if (err < 0)
1993 				goto _end_unlock;
1994 		}
1995 		frames = size > avail ? avail : size;
1996 		cont = runtime->buffer_size - runtime->control->appl_ptr % runtime->buffer_size;
1997 		if (frames > cont)
1998 			frames = cont;
1999 		if (snd_BUG_ON(!frames)) {
2000 			runtime->twake = 0;
2001 			snd_pcm_stream_unlock_irq(substream);
2002 			return -EINVAL;
2003 		}
2004 		appl_ptr = runtime->control->appl_ptr;
2005 		appl_ofs = appl_ptr % runtime->buffer_size;
2006 		snd_pcm_stream_unlock_irq(substream);
2007 		err = transfer(substream, appl_ofs, data, offset, frames);
2008 		snd_pcm_stream_lock_irq(substream);
2009 		if (err < 0)
2010 			goto _end_unlock;
2011 		switch (runtime->status->state) {
2012 		case SNDRV_PCM_STATE_XRUN:
2013 			err = -EPIPE;
2014 			goto _end_unlock;
2015 		case SNDRV_PCM_STATE_SUSPENDED:
2016 			err = -ESTRPIPE;
2017 			goto _end_unlock;
2018 		default:
2019 			break;
2020 		}
2021 		appl_ptr += frames;
2022 		if (appl_ptr >= runtime->boundary)
2023 			appl_ptr -= runtime->boundary;
2024 		runtime->control->appl_ptr = appl_ptr;
2025 		if (substream->ops->ack)
2026 			substream->ops->ack(substream);
2027 
2028 		offset += frames;
2029 		size -= frames;
2030 		xfer += frames;
2031 		avail -= frames;
2032 		if (runtime->status->state == SNDRV_PCM_STATE_PREPARED &&
2033 		    snd_pcm_playback_hw_avail(runtime) >= (snd_pcm_sframes_t)runtime->start_threshold) {
2034 			err = snd_pcm_start(substream);
2035 			if (err < 0)
2036 				goto _end_unlock;
2037 		}
2038 	}
2039  _end_unlock:
2040 	runtime->twake = 0;
2041 	if (xfer > 0 && err >= 0)
2042 		snd_pcm_update_state(substream, runtime);
2043 	snd_pcm_stream_unlock_irq(substream);
2044 	return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
2045 }
2046 
2047 /* sanity-check for read/write methods */
2048 static int pcm_sanity_check(struct snd_pcm_substream *substream)
2049 {
2050 	struct snd_pcm_runtime *runtime;
2051 	if (PCM_RUNTIME_CHECK(substream))
2052 		return -ENXIO;
2053 	runtime = substream->runtime;
2054 	if (snd_BUG_ON(!substream->ops->copy && !runtime->dma_area))
2055 		return -EINVAL;
2056 	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
2057 		return -EBADFD;
2058 	return 0;
2059 }
2060 
2061 snd_pcm_sframes_t snd_pcm_lib_write(struct snd_pcm_substream *substream, const void __user *buf, snd_pcm_uframes_t size)
2062 {
2063 	struct snd_pcm_runtime *runtime;
2064 	int nonblock;
2065 	int err;
2066 
2067 	err = pcm_sanity_check(substream);
2068 	if (err < 0)
2069 		return err;
2070 	runtime = substream->runtime;
2071 	nonblock = !!(substream->f_flags & O_NONBLOCK);
2072 
2073 	if (runtime->access != SNDRV_PCM_ACCESS_RW_INTERLEAVED &&
2074 	    runtime->channels > 1)
2075 		return -EINVAL;
2076 	return snd_pcm_lib_write1(substream, (unsigned long)buf, size, nonblock,
2077 				  snd_pcm_lib_write_transfer);
2078 }
2079 
2080 EXPORT_SYMBOL(snd_pcm_lib_write);
2081 
2082 static int snd_pcm_lib_writev_transfer(struct snd_pcm_substream *substream,
2083 				       unsigned int hwoff,
2084 				       unsigned long data, unsigned int off,
2085 				       snd_pcm_uframes_t frames)
2086 {
2087 	struct snd_pcm_runtime *runtime = substream->runtime;
2088 	int err;
2089 	void __user **bufs = (void __user **)data;
2090 	int channels = runtime->channels;
2091 	int c;
2092 	if (substream->ops->copy) {
2093 		if (snd_BUG_ON(!substream->ops->silence))
2094 			return -EINVAL;
2095 		for (c = 0; c < channels; ++c, ++bufs) {
2096 			if (*bufs == NULL) {
2097 				if ((err = substream->ops->silence(substream, c, hwoff, frames)) < 0)
2098 					return err;
2099 			} else {
2100 				char __user *buf = *bufs + samples_to_bytes(runtime, off);
2101 				if ((err = substream->ops->copy(substream, c, hwoff, buf, frames)) < 0)
2102 					return err;
2103 			}
2104 		}
2105 	} else {
2106 		/* default transfer behaviour */
2107 		size_t dma_csize = runtime->dma_bytes / channels;
2108 		for (c = 0; c < channels; ++c, ++bufs) {
2109 			char *hwbuf = runtime->dma_area + (c * dma_csize) + samples_to_bytes(runtime, hwoff);
2110 			if (*bufs == NULL) {
2111 				snd_pcm_format_set_silence(runtime->format, hwbuf, frames);
2112 			} else {
2113 				char __user *buf = *bufs + samples_to_bytes(runtime, off);
2114 				if (copy_from_user(hwbuf, buf, samples_to_bytes(runtime, frames)))
2115 					return -EFAULT;
2116 			}
2117 		}
2118 	}
2119 	return 0;
2120 }
2121 
2122 snd_pcm_sframes_t snd_pcm_lib_writev(struct snd_pcm_substream *substream,
2123 				     void __user **bufs,
2124 				     snd_pcm_uframes_t frames)
2125 {
2126 	struct snd_pcm_runtime *runtime;
2127 	int nonblock;
2128 	int err;
2129 
2130 	err = pcm_sanity_check(substream);
2131 	if (err < 0)
2132 		return err;
2133 	runtime = substream->runtime;
2134 	nonblock = !!(substream->f_flags & O_NONBLOCK);
2135 
2136 	if (runtime->access != SNDRV_PCM_ACCESS_RW_NONINTERLEAVED)
2137 		return -EINVAL;
2138 	return snd_pcm_lib_write1(substream, (unsigned long)bufs, frames,
2139 				  nonblock, snd_pcm_lib_writev_transfer);
2140 }
2141 
2142 EXPORT_SYMBOL(snd_pcm_lib_writev);
2143 
2144 static int snd_pcm_lib_read_transfer(struct snd_pcm_substream *substream,
2145 				     unsigned int hwoff,
2146 				     unsigned long data, unsigned int off,
2147 				     snd_pcm_uframes_t frames)
2148 {
2149 	struct snd_pcm_runtime *runtime = substream->runtime;
2150 	int err;
2151 	char __user *buf = (char __user *) data + frames_to_bytes(runtime, off);
2152 	if (substream->ops->copy) {
2153 		if ((err = substream->ops->copy(substream, -1, hwoff, buf, frames)) < 0)
2154 			return err;
2155 	} else {
2156 		char *hwbuf = runtime->dma_area + frames_to_bytes(runtime, hwoff);
2157 		if (copy_to_user(buf, hwbuf, frames_to_bytes(runtime, frames)))
2158 			return -EFAULT;
2159 	}
2160 	return 0;
2161 }
2162 
2163 static snd_pcm_sframes_t snd_pcm_lib_read1(struct snd_pcm_substream *substream,
2164 					   unsigned long data,
2165 					   snd_pcm_uframes_t size,
2166 					   int nonblock,
2167 					   transfer_f transfer)
2168 {
2169 	struct snd_pcm_runtime *runtime = substream->runtime;
2170 	snd_pcm_uframes_t xfer = 0;
2171 	snd_pcm_uframes_t offset = 0;
2172 	snd_pcm_uframes_t avail;
2173 	int err = 0;
2174 
2175 	if (size == 0)
2176 		return 0;
2177 
2178 	snd_pcm_stream_lock_irq(substream);
2179 	switch (runtime->status->state) {
2180 	case SNDRV_PCM_STATE_PREPARED:
2181 		if (size >= runtime->start_threshold) {
2182 			err = snd_pcm_start(substream);
2183 			if (err < 0)
2184 				goto _end_unlock;
2185 		}
2186 		break;
2187 	case SNDRV_PCM_STATE_DRAINING:
2188 	case SNDRV_PCM_STATE_RUNNING:
2189 	case SNDRV_PCM_STATE_PAUSED:
2190 		break;
2191 	case SNDRV_PCM_STATE_XRUN:
2192 		err = -EPIPE;
2193 		goto _end_unlock;
2194 	case SNDRV_PCM_STATE_SUSPENDED:
2195 		err = -ESTRPIPE;
2196 		goto _end_unlock;
2197 	default:
2198 		err = -EBADFD;
2199 		goto _end_unlock;
2200 	}
2201 
2202 	runtime->twake = runtime->control->avail_min ? : 1;
2203 	if (runtime->status->state == SNDRV_PCM_STATE_RUNNING)
2204 		snd_pcm_update_hw_ptr(substream);
2205 	avail = snd_pcm_capture_avail(runtime);
2206 	while (size > 0) {
2207 		snd_pcm_uframes_t frames, appl_ptr, appl_ofs;
2208 		snd_pcm_uframes_t cont;
2209 		if (!avail) {
2210 			if (runtime->status->state ==
2211 			    SNDRV_PCM_STATE_DRAINING) {
2212 				snd_pcm_stop(substream, SNDRV_PCM_STATE_SETUP);
2213 				goto _end_unlock;
2214 			}
2215 			if (nonblock) {
2216 				err = -EAGAIN;
2217 				goto _end_unlock;
2218 			}
2219 			runtime->twake = min_t(snd_pcm_uframes_t, size,
2220 					runtime->control->avail_min ? : 1);
2221 			err = wait_for_avail(substream, &avail);
2222 			if (err < 0)
2223 				goto _end_unlock;
2224 			if (!avail)
2225 				continue; /* draining */
2226 		}
2227 		frames = size > avail ? avail : size;
2228 		cont = runtime->buffer_size - runtime->control->appl_ptr % runtime->buffer_size;
2229 		if (frames > cont)
2230 			frames = cont;
2231 		if (snd_BUG_ON(!frames)) {
2232 			runtime->twake = 0;
2233 			snd_pcm_stream_unlock_irq(substream);
2234 			return -EINVAL;
2235 		}
2236 		appl_ptr = runtime->control->appl_ptr;
2237 		appl_ofs = appl_ptr % runtime->buffer_size;
2238 		snd_pcm_stream_unlock_irq(substream);
2239 		err = transfer(substream, appl_ofs, data, offset, frames);
2240 		snd_pcm_stream_lock_irq(substream);
2241 		if (err < 0)
2242 			goto _end_unlock;
2243 		switch (runtime->status->state) {
2244 		case SNDRV_PCM_STATE_XRUN:
2245 			err = -EPIPE;
2246 			goto _end_unlock;
2247 		case SNDRV_PCM_STATE_SUSPENDED:
2248 			err = -ESTRPIPE;
2249 			goto _end_unlock;
2250 		default:
2251 			break;
2252 		}
2253 		appl_ptr += frames;
2254 		if (appl_ptr >= runtime->boundary)
2255 			appl_ptr -= runtime->boundary;
2256 		runtime->control->appl_ptr = appl_ptr;
2257 		if (substream->ops->ack)
2258 			substream->ops->ack(substream);
2259 
2260 		offset += frames;
2261 		size -= frames;
2262 		xfer += frames;
2263 		avail -= frames;
2264 	}
2265  _end_unlock:
2266 	runtime->twake = 0;
2267 	if (xfer > 0 && err >= 0)
2268 		snd_pcm_update_state(substream, runtime);
2269 	snd_pcm_stream_unlock_irq(substream);
2270 	return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
2271 }
2272 
2273 snd_pcm_sframes_t snd_pcm_lib_read(struct snd_pcm_substream *substream, void __user *buf, snd_pcm_uframes_t size)
2274 {
2275 	struct snd_pcm_runtime *runtime;
2276 	int nonblock;
2277 	int err;
2278 
2279 	err = pcm_sanity_check(substream);
2280 	if (err < 0)
2281 		return err;
2282 	runtime = substream->runtime;
2283 	nonblock = !!(substream->f_flags & O_NONBLOCK);
2284 	if (runtime->access != SNDRV_PCM_ACCESS_RW_INTERLEAVED)
2285 		return -EINVAL;
2286 	return snd_pcm_lib_read1(substream, (unsigned long)buf, size, nonblock, snd_pcm_lib_read_transfer);
2287 }
2288 
2289 EXPORT_SYMBOL(snd_pcm_lib_read);
2290 
2291 static int snd_pcm_lib_readv_transfer(struct snd_pcm_substream *substream,
2292 				      unsigned int hwoff,
2293 				      unsigned long data, unsigned int off,
2294 				      snd_pcm_uframes_t frames)
2295 {
2296 	struct snd_pcm_runtime *runtime = substream->runtime;
2297 	int err;
2298 	void __user **bufs = (void __user **)data;
2299 	int channels = runtime->channels;
2300 	int c;
2301 	if (substream->ops->copy) {
2302 		for (c = 0; c < channels; ++c, ++bufs) {
2303 			char __user *buf;
2304 			if (*bufs == NULL)
2305 				continue;
2306 			buf = *bufs + samples_to_bytes(runtime, off);
2307 			if ((err = substream->ops->copy(substream, c, hwoff, buf, frames)) < 0)
2308 				return err;
2309 		}
2310 	} else {
2311 		snd_pcm_uframes_t dma_csize = runtime->dma_bytes / channels;
2312 		for (c = 0; c < channels; ++c, ++bufs) {
2313 			char *hwbuf;
2314 			char __user *buf;
2315 			if (*bufs == NULL)
2316 				continue;
2317 
2318 			hwbuf = runtime->dma_area + (c * dma_csize) + samples_to_bytes(runtime, hwoff);
2319 			buf = *bufs + samples_to_bytes(runtime, off);
2320 			if (copy_to_user(buf, hwbuf, samples_to_bytes(runtime, frames)))
2321 				return -EFAULT;
2322 		}
2323 	}
2324 	return 0;
2325 }
2326 
2327 snd_pcm_sframes_t snd_pcm_lib_readv(struct snd_pcm_substream *substream,
2328 				    void __user **bufs,
2329 				    snd_pcm_uframes_t frames)
2330 {
2331 	struct snd_pcm_runtime *runtime;
2332 	int nonblock;
2333 	int err;
2334 
2335 	err = pcm_sanity_check(substream);
2336 	if (err < 0)
2337 		return err;
2338 	runtime = substream->runtime;
2339 	if (runtime->status->state == SNDRV_PCM_STATE_OPEN)
2340 		return -EBADFD;
2341 
2342 	nonblock = !!(substream->f_flags & O_NONBLOCK);
2343 	if (runtime->access != SNDRV_PCM_ACCESS_RW_NONINTERLEAVED)
2344 		return -EINVAL;
2345 	return snd_pcm_lib_read1(substream, (unsigned long)bufs, frames, nonblock, snd_pcm_lib_readv_transfer);
2346 }
2347 
2348 EXPORT_SYMBOL(snd_pcm_lib_readv);
2349 
2350 /*
2351  * standard channel mapping helpers
2352  */
2353 
2354 /* default channel maps for multi-channel playbacks, up to 8 channels */
2355 const struct snd_pcm_chmap_elem snd_pcm_std_chmaps[] = {
2356 	{ .channels = 1,
2357 	  .map = { SNDRV_CHMAP_MONO } },
2358 	{ .channels = 2,
2359 	  .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR } },
2360 	{ .channels = 4,
2361 	  .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
2362 		   SNDRV_CHMAP_RL, SNDRV_CHMAP_RR } },
2363 	{ .channels = 6,
2364 	  .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
2365 		   SNDRV_CHMAP_RL, SNDRV_CHMAP_RR,
2366 		   SNDRV_CHMAP_FC, SNDRV_CHMAP_LFE } },
2367 	{ .channels = 8,
2368 	  .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
2369 		   SNDRV_CHMAP_RL, SNDRV_CHMAP_RR,
2370 		   SNDRV_CHMAP_FC, SNDRV_CHMAP_LFE,
2371 		   SNDRV_CHMAP_SL, SNDRV_CHMAP_SR } },
2372 	{ }
2373 };
2374 EXPORT_SYMBOL_GPL(snd_pcm_std_chmaps);
2375 
2376 /* alternative channel maps with CLFE <-> surround swapped for 6/8 channels */
2377 const struct snd_pcm_chmap_elem snd_pcm_alt_chmaps[] = {
2378 	{ .channels = 1,
2379 	  .map = { SNDRV_CHMAP_MONO } },
2380 	{ .channels = 2,
2381 	  .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR } },
2382 	{ .channels = 4,
2383 	  .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
2384 		   SNDRV_CHMAP_RL, SNDRV_CHMAP_RR } },
2385 	{ .channels = 6,
2386 	  .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
2387 		   SNDRV_CHMAP_FC, SNDRV_CHMAP_LFE,
2388 		   SNDRV_CHMAP_RL, SNDRV_CHMAP_RR } },
2389 	{ .channels = 8,
2390 	  .map = { SNDRV_CHMAP_FL, SNDRV_CHMAP_FR,
2391 		   SNDRV_CHMAP_FC, SNDRV_CHMAP_LFE,
2392 		   SNDRV_CHMAP_RL, SNDRV_CHMAP_RR,
2393 		   SNDRV_CHMAP_SL, SNDRV_CHMAP_SR } },
2394 	{ }
2395 };
2396 EXPORT_SYMBOL_GPL(snd_pcm_alt_chmaps);
2397 
2398 static bool valid_chmap_channels(const struct snd_pcm_chmap *info, int ch)
2399 {
2400 	if (ch > info->max_channels)
2401 		return false;
2402 	return !info->channel_mask || (info->channel_mask & (1U << ch));
2403 }
2404 
2405 static int pcm_chmap_ctl_info(struct snd_kcontrol *kcontrol,
2406 			      struct snd_ctl_elem_info *uinfo)
2407 {
2408 	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
2409 
2410 	uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
2411 	uinfo->count = 0;
2412 	uinfo->count = info->max_channels;
2413 	uinfo->value.integer.min = 0;
2414 	uinfo->value.integer.max = SNDRV_CHMAP_LAST;
2415 	return 0;
2416 }
2417 
2418 /* get callback for channel map ctl element
2419  * stores the channel position firstly matching with the current channels
2420  */
2421 static int pcm_chmap_ctl_get(struct snd_kcontrol *kcontrol,
2422 			     struct snd_ctl_elem_value *ucontrol)
2423 {
2424 	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
2425 	unsigned int idx = snd_ctl_get_ioffidx(kcontrol, &ucontrol->id);
2426 	struct snd_pcm_substream *substream;
2427 	const struct snd_pcm_chmap_elem *map;
2428 
2429 	if (snd_BUG_ON(!info->chmap))
2430 		return -EINVAL;
2431 	substream = snd_pcm_chmap_substream(info, idx);
2432 	if (!substream)
2433 		return -ENODEV;
2434 	memset(ucontrol->value.integer.value, 0,
2435 	       sizeof(ucontrol->value.integer.value));
2436 	if (!substream->runtime)
2437 		return 0; /* no channels set */
2438 	for (map = info->chmap; map->channels; map++) {
2439 		int i;
2440 		if (map->channels == substream->runtime->channels &&
2441 		    valid_chmap_channels(info, map->channels)) {
2442 			for (i = 0; i < map->channels; i++)
2443 				ucontrol->value.integer.value[i] = map->map[i];
2444 			return 0;
2445 		}
2446 	}
2447 	return -EINVAL;
2448 }
2449 
2450 /* tlv callback for channel map ctl element
2451  * expands the pre-defined channel maps in a form of TLV
2452  */
2453 static int pcm_chmap_ctl_tlv(struct snd_kcontrol *kcontrol, int op_flag,
2454 			     unsigned int size, unsigned int __user *tlv)
2455 {
2456 	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
2457 	const struct snd_pcm_chmap_elem *map;
2458 	unsigned int __user *dst;
2459 	int c, count = 0;
2460 
2461 	if (snd_BUG_ON(!info->chmap))
2462 		return -EINVAL;
2463 	if (size < 8)
2464 		return -ENOMEM;
2465 	if (put_user(SNDRV_CTL_TLVT_CONTAINER, tlv))
2466 		return -EFAULT;
2467 	size -= 8;
2468 	dst = tlv + 2;
2469 	for (map = info->chmap; map->channels; map++) {
2470 		int chs_bytes = map->channels * 4;
2471 		if (!valid_chmap_channels(info, map->channels))
2472 			continue;
2473 		if (size < 8)
2474 			return -ENOMEM;
2475 		if (put_user(SNDRV_CTL_TLVT_CHMAP_FIXED, dst) ||
2476 		    put_user(chs_bytes, dst + 1))
2477 			return -EFAULT;
2478 		dst += 2;
2479 		size -= 8;
2480 		count += 8;
2481 		if (size < chs_bytes)
2482 			return -ENOMEM;
2483 		size -= chs_bytes;
2484 		count += chs_bytes;
2485 		for (c = 0; c < map->channels; c++) {
2486 			if (put_user(map->map[c], dst))
2487 				return -EFAULT;
2488 			dst++;
2489 		}
2490 	}
2491 	if (put_user(count, tlv + 1))
2492 		return -EFAULT;
2493 	return 0;
2494 }
2495 
2496 static void pcm_chmap_ctl_private_free(struct snd_kcontrol *kcontrol)
2497 {
2498 	struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
2499 	info->pcm->streams[info->stream].chmap_kctl = NULL;
2500 	kfree(info);
2501 }
2502 
2503 /**
2504  * snd_pcm_add_chmap_ctls - create channel-mapping control elements
2505  * @pcm: the assigned PCM instance
2506  * @stream: stream direction
2507  * @chmap: channel map elements (for query)
2508  * @max_channels: the max number of channels for the stream
2509  * @private_value: the value passed to each kcontrol's private_value field
2510  * @info_ret: store struct snd_pcm_chmap instance if non-NULL
2511  *
2512  * Create channel-mapping control elements assigned to the given PCM stream(s).
2513  * Returns zero if succeed, or a negative error value.
2514  */
2515 int snd_pcm_add_chmap_ctls(struct snd_pcm *pcm, int stream,
2516 			   const struct snd_pcm_chmap_elem *chmap,
2517 			   int max_channels,
2518 			   unsigned long private_value,
2519 			   struct snd_pcm_chmap **info_ret)
2520 {
2521 	struct snd_pcm_chmap *info;
2522 	struct snd_kcontrol_new knew = {
2523 		.iface = SNDRV_CTL_ELEM_IFACE_PCM,
2524 		.access = SNDRV_CTL_ELEM_ACCESS_READ |
2525 			SNDRV_CTL_ELEM_ACCESS_TLV_READ |
2526 			SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK,
2527 		.info = pcm_chmap_ctl_info,
2528 		.get = pcm_chmap_ctl_get,
2529 		.tlv.c = pcm_chmap_ctl_tlv,
2530 	};
2531 	int err;
2532 
2533 	info = kzalloc(sizeof(*info), GFP_KERNEL);
2534 	if (!info)
2535 		return -ENOMEM;
2536 	info->pcm = pcm;
2537 	info->stream = stream;
2538 	info->chmap = chmap;
2539 	info->max_channels = max_channels;
2540 	if (stream == SNDRV_PCM_STREAM_PLAYBACK)
2541 		knew.name = "Playback Channel Map";
2542 	else
2543 		knew.name = "Capture Channel Map";
2544 	knew.device = pcm->device;
2545 	knew.count = pcm->streams[stream].substream_count;
2546 	knew.private_value = private_value;
2547 	info->kctl = snd_ctl_new1(&knew, info);
2548 	if (!info->kctl) {
2549 		kfree(info);
2550 		return -ENOMEM;
2551 	}
2552 	info->kctl->private_free = pcm_chmap_ctl_private_free;
2553 	err = snd_ctl_add(pcm->card, info->kctl);
2554 	if (err < 0)
2555 		return err;
2556 	pcm->streams[stream].chmap_kctl = info->kctl;
2557 	if (info_ret)
2558 		*info_ret = info;
2559 	return 0;
2560 }
2561 EXPORT_SYMBOL_GPL(snd_pcm_add_chmap_ctls);
2562