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1 /* pcm.c
2 **
3 ** Copyright 2011, The Android Open Source Project
4 **
5 ** Redistribution and use in source and binary forms, with or without
6 ** modification, are permitted provided that the following conditions are met:
7 **     * Redistributions of source code must retain the above copyright
8 **       notice, this list of conditions and the following disclaimer.
9 **     * Redistributions in binary form must reproduce the above copyright
10 **       notice, this list of conditions and the following disclaimer in the
11 **       documentation and/or other materials provided with the distribution.
12 **     * Neither the name of The Android Open Source Project nor the names of
13 **       its contributors may be used to endorse or promote products derived
14 **       from this software without specific prior written permission.
15 **
16 ** THIS SOFTWARE IS PROVIDED BY The Android Open Source Project ``AS IS'' AND
17 ** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 ** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 ** ARE DISCLAIMED. IN NO EVENT SHALL The Android Open Source Project BE LIABLE
20 ** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 ** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22 ** SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
23 ** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 ** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
26 ** DAMAGE.
27 */
28 
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <fcntl.h>
32 #include <stdarg.h>
33 #include <string.h>
34 #include <errno.h>
35 #include <unistd.h>
36 #include <poll.h>
37 
38 #include <sys/ioctl.h>
39 #include <sys/mman.h>
40 #include <sys/time.h>
41 #include <limits.h>
42 
43 #include <linux/ioctl.h>
44 #define __force
45 #define __bitwise
46 #define __user
47 #include <sound/asound.h>
48 
49 #include <tinyalsa/asoundlib.h>
50 
51 #define PARAM_MAX SNDRV_PCM_HW_PARAM_LAST_INTERVAL
52 #define SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP (1<<2)
53 
54 /* Logs information into a string; follows snprintf() in that
55  * offset may be greater than size, and though no characters are copied
56  * into string, characters are still counted into offset. */
57 #define STRLOG(string, offset, size, ...) \
58     do { int temp, clipoffset = offset > size ? size : offset; \
59          temp = snprintf(string + clipoffset, size - clipoffset, __VA_ARGS__); \
60          if (temp > 0) offset += temp; } while (0)
61 
62 #ifndef ARRAY_SIZE
63 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
64 #endif
65 
66 /* refer to SNDRV_PCM_ACCESS_##index in sound/asound.h. */
67 static const char * const access_lookup[] = {
68         "MMAP_INTERLEAVED",
69         "MMAP_NONINTERLEAVED",
70         "MMAP_COMPLEX",
71         "RW_INTERLEAVED",
72         "RW_NONINTERLEAVED",
73 };
74 
75 /* refer to SNDRV_PCM_FORMAT_##index in sound/asound.h. */
76 static const char * const format_lookup[] = {
77         /*[0] =*/ "S8",
78         "U8",
79         "S16_LE",
80         "S16_BE",
81         "U16_LE",
82         "U16_BE",
83         "S24_LE",
84         "S24_BE",
85         "U24_LE",
86         "U24_BE",
87         "S32_LE",
88         "S32_BE",
89         "U32_LE",
90         "U32_BE",
91         "FLOAT_LE",
92         "FLOAT_BE",
93         "FLOAT64_LE",
94         "FLOAT64_BE",
95         "IEC958_SUBFRAME_LE",
96         "IEC958_SUBFRAME_BE",
97         "MU_LAW",
98         "A_LAW",
99         "IMA_ADPCM",
100         "MPEG",
101         /*[24] =*/ "GSM",
102         /* gap */
103         [31] = "SPECIAL",
104         "S24_3LE",
105         "S24_3BE",
106         "U24_3LE",
107         "U24_3BE",
108         "S20_3LE",
109         "S20_3BE",
110         "U20_3LE",
111         "U20_3BE",
112         "S18_3LE",
113         "S18_3BE",
114         "U18_3LE",
115         /*[43] =*/ "U18_3BE",
116 #if 0
117         /* recent additions, may not be present on local asound.h */
118         "G723_24",
119         "G723_24_1B",
120         "G723_40",
121         "G723_40_1B",
122         "DSD_U8",
123         "DSD_U16_LE",
124 #endif
125 };
126 
127 /* refer to SNDRV_PCM_SUBFORMAT_##index in sound/asound.h. */
128 static const char * const subformat_lookup[] = {
129         "STD",
130 };
131 
param_is_mask(int p)132 static inline int param_is_mask(int p)
133 {
134     return (p >= SNDRV_PCM_HW_PARAM_FIRST_MASK) &&
135         (p <= SNDRV_PCM_HW_PARAM_LAST_MASK);
136 }
137 
param_is_interval(int p)138 static inline int param_is_interval(int p)
139 {
140     return (p >= SNDRV_PCM_HW_PARAM_FIRST_INTERVAL) &&
141         (p <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL);
142 }
143 
param_to_interval(struct snd_pcm_hw_params * p,int n)144 static inline struct snd_interval *param_to_interval(struct snd_pcm_hw_params *p, int n)
145 {
146     return &(p->intervals[n - SNDRV_PCM_HW_PARAM_FIRST_INTERVAL]);
147 }
148 
param_to_mask(struct snd_pcm_hw_params * p,int n)149 static inline struct snd_mask *param_to_mask(struct snd_pcm_hw_params *p, int n)
150 {
151     return &(p->masks[n - SNDRV_PCM_HW_PARAM_FIRST_MASK]);
152 }
153 
param_set_mask(struct snd_pcm_hw_params * p,int n,unsigned int bit)154 static void param_set_mask(struct snd_pcm_hw_params *p, int n, unsigned int bit)
155 {
156     if (bit >= SNDRV_MASK_MAX)
157         return;
158     if (param_is_mask(n)) {
159         struct snd_mask *m = param_to_mask(p, n);
160         m->bits[0] = 0;
161         m->bits[1] = 0;
162         m->bits[bit >> 5] |= (1 << (bit & 31));
163     }
164 }
165 
param_set_min(struct snd_pcm_hw_params * p,int n,unsigned int val)166 static void param_set_min(struct snd_pcm_hw_params *p, int n, unsigned int val)
167 {
168     if (param_is_interval(n)) {
169         struct snd_interval *i = param_to_interval(p, n);
170         i->min = val;
171     }
172 }
173 
param_get_min(struct snd_pcm_hw_params * p,int n)174 static unsigned int param_get_min(struct snd_pcm_hw_params *p, int n)
175 {
176     if (param_is_interval(n)) {
177         struct snd_interval *i = param_to_interval(p, n);
178         return i->min;
179     }
180     return 0;
181 }
182 
param_set_max(struct snd_pcm_hw_params * p,int n,unsigned int val)183 static void param_set_max(struct snd_pcm_hw_params *p, int n, unsigned int val)
184 {
185     if (param_is_interval(n)) {
186         struct snd_interval *i = param_to_interval(p, n);
187         i->max = val;
188     }
189 }
190 
param_get_max(struct snd_pcm_hw_params * p,int n)191 static unsigned int param_get_max(struct snd_pcm_hw_params *p, int n)
192 {
193     if (param_is_interval(n)) {
194         struct snd_interval *i = param_to_interval(p, n);
195         return i->max;
196     }
197     return 0;
198 }
199 
param_set_int(struct snd_pcm_hw_params * p,int n,unsigned int val)200 static void param_set_int(struct snd_pcm_hw_params *p, int n, unsigned int val)
201 {
202     if (param_is_interval(n)) {
203         struct snd_interval *i = param_to_interval(p, n);
204         i->min = val;
205         i->max = val;
206         i->integer = 1;
207     }
208 }
209 
param_get_int(struct snd_pcm_hw_params * p,int n)210 static unsigned int param_get_int(struct snd_pcm_hw_params *p, int n)
211 {
212     if (param_is_interval(n)) {
213         struct snd_interval *i = param_to_interval(p, n);
214         if (i->integer)
215             return i->max;
216     }
217     return 0;
218 }
219 
param_init(struct snd_pcm_hw_params * p)220 static void param_init(struct snd_pcm_hw_params *p)
221 {
222     int n;
223 
224     memset(p, 0, sizeof(*p));
225     for (n = SNDRV_PCM_HW_PARAM_FIRST_MASK;
226          n <= SNDRV_PCM_HW_PARAM_LAST_MASK; n++) {
227             struct snd_mask *m = param_to_mask(p, n);
228             m->bits[0] = ~0;
229             m->bits[1] = ~0;
230     }
231     for (n = SNDRV_PCM_HW_PARAM_FIRST_INTERVAL;
232          n <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; n++) {
233             struct snd_interval *i = param_to_interval(p, n);
234             i->min = 0;
235             i->max = ~0;
236     }
237     p->rmask = ~0U;
238     p->cmask = 0;
239     p->info = ~0U;
240 }
241 
242 #define PCM_ERROR_MAX 128
243 
244 struct pcm {
245     int fd;
246     unsigned int flags;
247     int running:1;
248     int prepared:1;
249     int underruns;
250     unsigned int buffer_size;
251     unsigned int boundary;
252     char error[PCM_ERROR_MAX];
253     struct pcm_config config;
254     struct snd_pcm_mmap_status *mmap_status;
255     struct snd_pcm_mmap_control *mmap_control;
256     struct snd_pcm_sync_ptr *sync_ptr;
257     void *mmap_buffer;
258     unsigned int noirq_frames_per_msec;
259     int wait_for_avail_min;
260 };
261 
pcm_get_buffer_size(struct pcm * pcm)262 unsigned int pcm_get_buffer_size(struct pcm *pcm)
263 {
264     return pcm->buffer_size;
265 }
266 
pcm_get_error(struct pcm * pcm)267 const char* pcm_get_error(struct pcm *pcm)
268 {
269     return pcm->error;
270 }
271 
oops(struct pcm * pcm,int e,const char * fmt,...)272 static int oops(struct pcm *pcm, int e, const char *fmt, ...)
273 {
274     va_list ap;
275     int sz;
276 
277     va_start(ap, fmt);
278     vsnprintf(pcm->error, PCM_ERROR_MAX, fmt, ap);
279     va_end(ap);
280     sz = strlen(pcm->error);
281 
282     if (errno)
283         snprintf(pcm->error + sz, PCM_ERROR_MAX - sz,
284                  ": %s", strerror(e));
285     return -1;
286 }
287 
pcm_format_to_alsa(enum pcm_format format)288 static unsigned int pcm_format_to_alsa(enum pcm_format format)
289 {
290     switch (format) {
291     case PCM_FORMAT_S32_LE:
292         return SNDRV_PCM_FORMAT_S32_LE;
293     case PCM_FORMAT_S8:
294         return SNDRV_PCM_FORMAT_S8;
295     case PCM_FORMAT_S24_3LE:
296         return SNDRV_PCM_FORMAT_S24_3LE;
297     case PCM_FORMAT_S24_LE:
298         return SNDRV_PCM_FORMAT_S24_LE;
299     default:
300     case PCM_FORMAT_S16_LE:
301         return SNDRV_PCM_FORMAT_S16_LE;
302     };
303 }
304 
pcm_format_to_bits(enum pcm_format format)305 unsigned int pcm_format_to_bits(enum pcm_format format)
306 {
307     switch (format) {
308     case PCM_FORMAT_S32_LE:
309     case PCM_FORMAT_S24_LE:
310         return 32;
311     case PCM_FORMAT_S24_3LE:
312         return 24;
313     default:
314     case PCM_FORMAT_S16_LE:
315         return 16;
316     };
317 }
318 
pcm_bytes_to_frames(struct pcm * pcm,unsigned int bytes)319 unsigned int pcm_bytes_to_frames(struct pcm *pcm, unsigned int bytes)
320 {
321     return bytes / (pcm->config.channels *
322         (pcm_format_to_bits(pcm->config.format) >> 3));
323 }
324 
pcm_frames_to_bytes(struct pcm * pcm,unsigned int frames)325 unsigned int pcm_frames_to_bytes(struct pcm *pcm, unsigned int frames)
326 {
327     return frames * pcm->config.channels *
328         (pcm_format_to_bits(pcm->config.format) >> 3);
329 }
330 
pcm_sync_ptr(struct pcm * pcm,int flags)331 static int pcm_sync_ptr(struct pcm *pcm, int flags) {
332     if (pcm->sync_ptr) {
333         pcm->sync_ptr->flags = flags;
334         if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SYNC_PTR, pcm->sync_ptr) < 0)
335             return -1;
336     }
337     return 0;
338 }
339 
pcm_hw_mmap_status(struct pcm * pcm)340 static int pcm_hw_mmap_status(struct pcm *pcm) {
341 
342     if (pcm->sync_ptr)
343         return 0;
344 
345     int page_size = sysconf(_SC_PAGE_SIZE);
346     pcm->mmap_status = mmap(NULL, page_size, PROT_READ, MAP_FILE | MAP_SHARED,
347                             pcm->fd, SNDRV_PCM_MMAP_OFFSET_STATUS);
348     if (pcm->mmap_status == MAP_FAILED)
349         pcm->mmap_status = NULL;
350     if (!pcm->mmap_status)
351         goto mmap_error;
352 
353     pcm->mmap_control = mmap(NULL, page_size, PROT_READ | PROT_WRITE,
354                              MAP_FILE | MAP_SHARED, pcm->fd, SNDRV_PCM_MMAP_OFFSET_CONTROL);
355     if (pcm->mmap_control == MAP_FAILED)
356         pcm->mmap_control = NULL;
357     if (!pcm->mmap_control) {
358         munmap(pcm->mmap_status, page_size);
359         pcm->mmap_status = NULL;
360         goto mmap_error;
361     }
362     if (pcm->flags & PCM_MMAP)
363         pcm->mmap_control->avail_min = pcm->config.avail_min;
364     else
365         pcm->mmap_control->avail_min = 1;
366 
367     return 0;
368 
369 mmap_error:
370 
371     pcm->sync_ptr = calloc(1, sizeof(*pcm->sync_ptr));
372     if (!pcm->sync_ptr)
373         return -ENOMEM;
374     pcm->mmap_status = &pcm->sync_ptr->s.status;
375     pcm->mmap_control = &pcm->sync_ptr->c.control;
376     if (pcm->flags & PCM_MMAP)
377         pcm->mmap_control->avail_min = pcm->config.avail_min;
378     else
379         pcm->mmap_control->avail_min = 1;
380 
381     pcm_sync_ptr(pcm, 0);
382 
383     return 0;
384 }
385 
pcm_hw_munmap_status(struct pcm * pcm)386 static void pcm_hw_munmap_status(struct pcm *pcm) {
387     if (pcm->sync_ptr) {
388         free(pcm->sync_ptr);
389         pcm->sync_ptr = NULL;
390     } else {
391         int page_size = sysconf(_SC_PAGE_SIZE);
392         if (pcm->mmap_status)
393             munmap(pcm->mmap_status, page_size);
394         if (pcm->mmap_control)
395             munmap(pcm->mmap_control, page_size);
396     }
397     pcm->mmap_status = NULL;
398     pcm->mmap_control = NULL;
399 }
400 
pcm_areas_copy(struct pcm * pcm,unsigned int pcm_offset,char * buf,unsigned int src_offset,unsigned int frames)401 static int pcm_areas_copy(struct pcm *pcm, unsigned int pcm_offset,
402                           char *buf, unsigned int src_offset,
403                           unsigned int frames)
404 {
405     int size_bytes = pcm_frames_to_bytes(pcm, frames);
406     int pcm_offset_bytes = pcm_frames_to_bytes(pcm, pcm_offset);
407     int src_offset_bytes = pcm_frames_to_bytes(pcm, src_offset);
408 
409     /* interleaved only atm */
410     if (pcm->flags & PCM_IN)
411         memcpy(buf + src_offset_bytes,
412                (char*)pcm->mmap_buffer + pcm_offset_bytes,
413                size_bytes);
414     else
415         memcpy((char*)pcm->mmap_buffer + pcm_offset_bytes,
416                buf + src_offset_bytes,
417                size_bytes);
418     return 0;
419 }
420 
pcm_mmap_transfer_areas(struct pcm * pcm,char * buf,unsigned int offset,unsigned int size)421 static int pcm_mmap_transfer_areas(struct pcm *pcm, char *buf,
422                                 unsigned int offset, unsigned int size)
423 {
424     void *pcm_areas;
425     int commit;
426     unsigned int pcm_offset, frames, count = 0;
427 
428     while (size > 0) {
429         frames = size;
430         pcm_mmap_begin(pcm, &pcm_areas, &pcm_offset, &frames);
431         pcm_areas_copy(pcm, pcm_offset, buf, offset, frames);
432         commit = pcm_mmap_commit(pcm, pcm_offset, frames);
433         if (commit < 0) {
434             oops(pcm, commit, "failed to commit %d frames\n", frames);
435             return commit;
436         }
437 
438         offset += commit;
439         count += commit;
440         size -= commit;
441     }
442     return count;
443 }
444 
pcm_get_htimestamp(struct pcm * pcm,unsigned int * avail,struct timespec * tstamp)445 int pcm_get_htimestamp(struct pcm *pcm, unsigned int *avail,
446                        struct timespec *tstamp)
447 {
448     int frames;
449     int rc;
450     snd_pcm_uframes_t hw_ptr;
451 
452     if (!pcm_is_ready(pcm))
453         return -1;
454 
455     rc = pcm_sync_ptr(pcm, SNDRV_PCM_SYNC_PTR_APPL|SNDRV_PCM_SYNC_PTR_HWSYNC);
456     if (rc < 0)
457         return -1;
458 
459     if ((pcm->mmap_status->state != PCM_STATE_RUNNING) &&
460             (pcm->mmap_status->state != PCM_STATE_DRAINING))
461         return -1;
462 
463     *tstamp = pcm->mmap_status->tstamp;
464     if (tstamp->tv_sec == 0 && tstamp->tv_nsec == 0)
465         return -1;
466 
467     hw_ptr = pcm->mmap_status->hw_ptr;
468     if (pcm->flags & PCM_IN)
469         frames = hw_ptr - pcm->mmap_control->appl_ptr;
470     else
471         frames = hw_ptr + pcm->buffer_size - pcm->mmap_control->appl_ptr;
472 
473     if (frames < 0)
474         frames += pcm->boundary;
475     else if (frames > (int)pcm->boundary)
476         frames -= pcm->boundary;
477 
478     *avail = (unsigned int)frames;
479 
480     return 0;
481 }
482 
pcm_write(struct pcm * pcm,const void * data,unsigned int count)483 int pcm_write(struct pcm *pcm, const void *data, unsigned int count)
484 {
485     struct snd_xferi x;
486 
487     if (pcm->flags & PCM_IN)
488         return -EINVAL;
489 
490     x.buf = (void*)data;
491     x.frames = count / (pcm->config.channels *
492                         pcm_format_to_bits(pcm->config.format) / 8);
493 
494     for (;;) {
495         if (!pcm->running) {
496             int prepare_error = pcm_prepare(pcm);
497             if (prepare_error)
498                 return prepare_error;
499             if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_WRITEI_FRAMES, &x))
500                 return oops(pcm, errno, "cannot write initial data");
501             pcm->running = 1;
502             return 0;
503         }
504         if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_WRITEI_FRAMES, &x)) {
505             pcm->prepared = 0;
506             pcm->running = 0;
507             if (errno == EPIPE) {
508                 /* we failed to make our window -- try to restart if we are
509                  * allowed to do so.  Otherwise, simply allow the EPIPE error to
510                  * propagate up to the app level */
511                 pcm->underruns++;
512                 if (pcm->flags & PCM_NORESTART)
513                     return -EPIPE;
514                 continue;
515             }
516             return oops(pcm, errno, "cannot write stream data");
517         }
518         return 0;
519     }
520 }
521 
pcm_read(struct pcm * pcm,void * data,unsigned int count)522 int pcm_read(struct pcm *pcm, void *data, unsigned int count)
523 {
524     struct snd_xferi x;
525 
526     if (!(pcm->flags & PCM_IN))
527         return -EINVAL;
528 
529     x.buf = data;
530     x.frames = count / (pcm->config.channels *
531                         pcm_format_to_bits(pcm->config.format) / 8);
532 
533     for (;;) {
534         if (!pcm->running) {
535             if (pcm_start(pcm) < 0) {
536                 fprintf(stderr, "start error");
537                 return -errno;
538             }
539         }
540         if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_READI_FRAMES, &x)) {
541             pcm->prepared = 0;
542             pcm->running = 0;
543             if (errno == EPIPE) {
544                     /* we failed to make our window -- try to restart */
545                 pcm->underruns++;
546                 continue;
547             }
548             return oops(pcm, errno, "cannot read stream data");
549         }
550         return 0;
551     }
552 }
553 
554 static struct pcm bad_pcm = {
555     .fd = -1,
556 };
557 
pcm_params_get(unsigned int card,unsigned int device,unsigned int flags)558 struct pcm_params *pcm_params_get(unsigned int card, unsigned int device,
559                                   unsigned int flags)
560 {
561     struct snd_pcm_hw_params *params;
562     char fn[256];
563     int fd;
564 
565     snprintf(fn, sizeof(fn), "/dev/snd/pcmC%uD%u%c", card, device,
566              flags & PCM_IN ? 'c' : 'p');
567 
568     fd = open(fn, O_RDWR);
569     if (fd < 0) {
570         fprintf(stderr, "cannot open device '%s'\n", fn);
571         goto err_open;
572     }
573 
574     params = calloc(1, sizeof(struct snd_pcm_hw_params));
575     if (!params)
576         goto err_calloc;
577 
578     param_init(params);
579     if (ioctl(fd, SNDRV_PCM_IOCTL_HW_REFINE, params)) {
580         fprintf(stderr, "SNDRV_PCM_IOCTL_HW_REFINE error (%d)\n", errno);
581         goto err_hw_refine;
582     }
583 
584     close(fd);
585 
586     return (struct pcm_params *)params;
587 
588 err_hw_refine:
589     free(params);
590 err_calloc:
591     close(fd);
592 err_open:
593     return NULL;
594 }
595 
pcm_params_free(struct pcm_params * pcm_params)596 void pcm_params_free(struct pcm_params *pcm_params)
597 {
598     struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params;
599 
600     if (params)
601         free(params);
602 }
603 
pcm_param_to_alsa(enum pcm_param param)604 static int pcm_param_to_alsa(enum pcm_param param)
605 {
606     switch (param) {
607     case PCM_PARAM_ACCESS:
608         return SNDRV_PCM_HW_PARAM_ACCESS;
609     case PCM_PARAM_FORMAT:
610         return SNDRV_PCM_HW_PARAM_FORMAT;
611     case PCM_PARAM_SUBFORMAT:
612         return SNDRV_PCM_HW_PARAM_SUBFORMAT;
613     case PCM_PARAM_SAMPLE_BITS:
614         return SNDRV_PCM_HW_PARAM_SAMPLE_BITS;
615         break;
616     case PCM_PARAM_FRAME_BITS:
617         return SNDRV_PCM_HW_PARAM_FRAME_BITS;
618         break;
619     case PCM_PARAM_CHANNELS:
620         return SNDRV_PCM_HW_PARAM_CHANNELS;
621         break;
622     case PCM_PARAM_RATE:
623         return SNDRV_PCM_HW_PARAM_RATE;
624         break;
625     case PCM_PARAM_PERIOD_TIME:
626         return SNDRV_PCM_HW_PARAM_PERIOD_TIME;
627         break;
628     case PCM_PARAM_PERIOD_SIZE:
629         return SNDRV_PCM_HW_PARAM_PERIOD_SIZE;
630         break;
631     case PCM_PARAM_PERIOD_BYTES:
632         return SNDRV_PCM_HW_PARAM_PERIOD_BYTES;
633         break;
634     case PCM_PARAM_PERIODS:
635         return SNDRV_PCM_HW_PARAM_PERIODS;
636         break;
637     case PCM_PARAM_BUFFER_TIME:
638         return SNDRV_PCM_HW_PARAM_BUFFER_TIME;
639         break;
640     case PCM_PARAM_BUFFER_SIZE:
641         return SNDRV_PCM_HW_PARAM_BUFFER_SIZE;
642         break;
643     case PCM_PARAM_BUFFER_BYTES:
644         return SNDRV_PCM_HW_PARAM_BUFFER_BYTES;
645         break;
646     case PCM_PARAM_TICK_TIME:
647         return SNDRV_PCM_HW_PARAM_TICK_TIME;
648         break;
649 
650     default:
651         return -1;
652     }
653 }
654 
pcm_params_get_mask(struct pcm_params * pcm_params,enum pcm_param param)655 struct pcm_mask *pcm_params_get_mask(struct pcm_params *pcm_params,
656                                      enum pcm_param param)
657 {
658     int p;
659     struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params;
660     if (params == NULL) {
661         return NULL;
662     }
663 
664     p = pcm_param_to_alsa(param);
665     if (p < 0 || !param_is_mask(p)) {
666         return NULL;
667     }
668 
669     return (struct pcm_mask *)param_to_mask(params, p);
670 }
671 
pcm_params_get_min(struct pcm_params * pcm_params,enum pcm_param param)672 unsigned int pcm_params_get_min(struct pcm_params *pcm_params,
673                                 enum pcm_param param)
674 {
675     struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params;
676     int p;
677 
678     if (!params)
679         return 0;
680 
681     p = pcm_param_to_alsa(param);
682     if (p < 0)
683         return 0;
684 
685     return param_get_min(params, p);
686 }
687 
pcm_params_set_min(struct pcm_params * pcm_params,enum pcm_param param,unsigned int val)688 void pcm_params_set_min(struct pcm_params *pcm_params,
689                                 enum pcm_param param, unsigned int val)
690 {
691     struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params;
692     int p;
693 
694     if (!params)
695         return;
696 
697     p = pcm_param_to_alsa(param);
698     if (p < 0)
699         return;
700 
701     param_set_min(params, p, val);
702 }
703 
pcm_params_get_max(struct pcm_params * pcm_params,enum pcm_param param)704 unsigned int pcm_params_get_max(struct pcm_params *pcm_params,
705                                 enum pcm_param param)
706 {
707     struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params;
708     int p;
709 
710     if (!params)
711         return 0;
712 
713     p = pcm_param_to_alsa(param);
714     if (p < 0)
715         return 0;
716 
717     return param_get_max(params, p);
718 }
719 
pcm_params_set_max(struct pcm_params * pcm_params,enum pcm_param param,unsigned int val)720 void pcm_params_set_max(struct pcm_params *pcm_params,
721                                 enum pcm_param param, unsigned int val)
722 {
723     struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params;
724     int p;
725 
726     if (!params)
727         return;
728 
729     p = pcm_param_to_alsa(param);
730     if (p < 0)
731         return;
732 
733     param_set_max(params, p, val);
734 }
735 
pcm_mask_test(struct pcm_mask * m,unsigned int index)736 static int pcm_mask_test(struct pcm_mask *m, unsigned int index)
737 {
738     const unsigned int bitshift = 5; /* for 32 bit integer */
739     const unsigned int bitmask = (1 << bitshift) - 1;
740     unsigned int element;
741 
742     element = index >> bitshift;
743     if (element >= ARRAY_SIZE(m->bits))
744         return 0; /* for safety, but should never occur */
745     return (m->bits[element] >> (index & bitmask)) & 1;
746 }
747 
pcm_mask_to_string(struct pcm_mask * m,char * string,unsigned int size,char * mask_name,const char * const * bit_array_name,size_t bit_array_size)748 static int pcm_mask_to_string(struct pcm_mask *m, char *string, unsigned int size,
749                               char *mask_name,
750                               const char * const *bit_array_name, size_t bit_array_size)
751 {
752     unsigned int i;
753     unsigned int offset = 0;
754 
755     if (m == NULL)
756         return 0;
757     if (bit_array_size < 32) {
758         STRLOG(string, offset, size, "%12s:\t%#08x\n", mask_name, m->bits[0]);
759     } else { /* spans two or more bitfields, print with an array index */
760         for (i = 0; i < (bit_array_size + 31) >> 5; ++i) {
761             STRLOG(string, offset, size, "%9s[%d]:\t%#08x\n",
762                    mask_name, i, m->bits[i]);
763         }
764     }
765     for (i = 0; i < bit_array_size; ++i) {
766         if (pcm_mask_test(m, i)) {
767             STRLOG(string, offset, size, "%12s \t%s\n", "", bit_array_name[i]);
768         }
769     }
770     return offset;
771 }
772 
pcm_params_to_string(struct pcm_params * params,char * string,unsigned int size)773 int pcm_params_to_string(struct pcm_params *params, char *string, unsigned int size)
774 {
775     struct pcm_mask *m;
776     unsigned int min, max;
777     unsigned int clipoffset, offset;
778 
779     m = pcm_params_get_mask(params, PCM_PARAM_ACCESS);
780     offset = pcm_mask_to_string(m, string, size,
781                                  "Access", access_lookup, ARRAY_SIZE(access_lookup));
782     m = pcm_params_get_mask(params, PCM_PARAM_FORMAT);
783     clipoffset = offset > size ? size : offset;
784     offset += pcm_mask_to_string(m, string + clipoffset, size - clipoffset,
785                                  "Format", format_lookup, ARRAY_SIZE(format_lookup));
786     m = pcm_params_get_mask(params, PCM_PARAM_SUBFORMAT);
787     clipoffset = offset > size ? size : offset;
788     offset += pcm_mask_to_string(m, string + clipoffset, size - clipoffset,
789                                  "Subformat", subformat_lookup, ARRAY_SIZE(subformat_lookup));
790     min = pcm_params_get_min(params, PCM_PARAM_RATE);
791     max = pcm_params_get_max(params, PCM_PARAM_RATE);
792     STRLOG(string, offset, size, "        Rate:\tmin=%uHz\tmax=%uHz\n", min, max);
793     min = pcm_params_get_min(params, PCM_PARAM_CHANNELS);
794     max = pcm_params_get_max(params, PCM_PARAM_CHANNELS);
795     STRLOG(string, offset, size, "    Channels:\tmin=%u\t\tmax=%u\n", min, max);
796     min = pcm_params_get_min(params, PCM_PARAM_SAMPLE_BITS);
797     max = pcm_params_get_max(params, PCM_PARAM_SAMPLE_BITS);
798     STRLOG(string, offset, size, " Sample bits:\tmin=%u\t\tmax=%u\n", min, max);
799     min = pcm_params_get_min(params, PCM_PARAM_PERIOD_SIZE);
800     max = pcm_params_get_max(params, PCM_PARAM_PERIOD_SIZE);
801     STRLOG(string, offset, size, " Period size:\tmin=%u\t\tmax=%u\n", min, max);
802     min = pcm_params_get_min(params, PCM_PARAM_PERIODS);
803     max = pcm_params_get_max(params, PCM_PARAM_PERIODS);
804     STRLOG(string, offset, size, "Period count:\tmin=%u\t\tmax=%u\n", min, max);
805     return offset;
806 }
807 
pcm_params_format_test(struct pcm_params * params,enum pcm_format format)808 int pcm_params_format_test(struct pcm_params *params, enum pcm_format format)
809 {
810     unsigned int alsa_format = pcm_format_to_alsa(format);
811 
812     if (alsa_format == SNDRV_PCM_FORMAT_S16_LE && format != PCM_FORMAT_S16_LE)
813         return 0; /* caution: format not recognized is equivalent to S16_LE */
814     return pcm_mask_test(pcm_params_get_mask(params, PCM_PARAM_FORMAT), alsa_format);
815 }
816 
pcm_close(struct pcm * pcm)817 int pcm_close(struct pcm *pcm)
818 {
819     if (pcm == &bad_pcm)
820         return 0;
821 
822     pcm_hw_munmap_status(pcm);
823 
824     if (pcm->flags & PCM_MMAP) {
825         pcm_stop(pcm);
826         munmap(pcm->mmap_buffer, pcm_frames_to_bytes(pcm, pcm->buffer_size));
827     }
828 
829     if (pcm->fd >= 0)
830         close(pcm->fd);
831     pcm->prepared = 0;
832     pcm->running = 0;
833     pcm->buffer_size = 0;
834     pcm->fd = -1;
835     free(pcm);
836     return 0;
837 }
838 
pcm_open(unsigned int card,unsigned int device,unsigned int flags,struct pcm_config * config)839 struct pcm *pcm_open(unsigned int card, unsigned int device,
840                      unsigned int flags, struct pcm_config *config)
841 {
842     struct pcm *pcm;
843     struct snd_pcm_info info;
844     struct snd_pcm_hw_params params;
845     struct snd_pcm_sw_params sparams;
846     char fn[256];
847     int rc;
848 
849     pcm = calloc(1, sizeof(struct pcm));
850     if (!pcm || !config)
851         return &bad_pcm; /* TODO: could support default config here */
852 
853     pcm->config = *config;
854 
855     snprintf(fn, sizeof(fn), "/dev/snd/pcmC%uD%u%c", card, device,
856              flags & PCM_IN ? 'c' : 'p');
857 
858     pcm->flags = flags;
859     pcm->fd = open(fn, O_RDWR);
860     if (pcm->fd < 0) {
861         oops(pcm, errno, "cannot open device '%s'", fn);
862         return pcm;
863     }
864 
865     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_INFO, &info)) {
866         oops(pcm, errno, "cannot get info");
867         goto fail_close;
868     }
869 
870     param_init(&params);
871     param_set_mask(&params, SNDRV_PCM_HW_PARAM_FORMAT,
872                    pcm_format_to_alsa(config->format));
873     param_set_mask(&params, SNDRV_PCM_HW_PARAM_SUBFORMAT,
874                    SNDRV_PCM_SUBFORMAT_STD);
875     param_set_min(&params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, config->period_size);
876     param_set_int(&params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS,
877                   pcm_format_to_bits(config->format));
878     param_set_int(&params, SNDRV_PCM_HW_PARAM_FRAME_BITS,
879                   pcm_format_to_bits(config->format) * config->channels);
880     param_set_int(&params, SNDRV_PCM_HW_PARAM_CHANNELS,
881                   config->channels);
882     param_set_int(&params, SNDRV_PCM_HW_PARAM_PERIODS, config->period_count);
883     param_set_int(&params, SNDRV_PCM_HW_PARAM_RATE, config->rate);
884 
885     if (flags & PCM_NOIRQ) {
886         if (!(flags & PCM_MMAP)) {
887             oops(pcm, -EINVAL, "noirq only currently supported with mmap().");
888             goto fail;
889         }
890 
891         params.flags |= SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP;
892         pcm->noirq_frames_per_msec = config->rate / 1000;
893     }
894 
895     if (flags & PCM_MMAP)
896         param_set_mask(&params, SNDRV_PCM_HW_PARAM_ACCESS,
897                        SNDRV_PCM_ACCESS_MMAP_INTERLEAVED);
898     else
899         param_set_mask(&params, SNDRV_PCM_HW_PARAM_ACCESS,
900                        SNDRV_PCM_ACCESS_RW_INTERLEAVED);
901 
902     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_HW_PARAMS, &params)) {
903         oops(pcm, errno, "cannot set hw params");
904         goto fail_close;
905     }
906 
907     /* get our refined hw_params */
908     config->period_size = param_get_int(&params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
909     config->period_count = param_get_int(&params, SNDRV_PCM_HW_PARAM_PERIODS);
910     pcm->buffer_size = config->period_count * config->period_size;
911 
912     if (flags & PCM_MMAP) {
913         pcm->mmap_buffer = mmap(NULL, pcm_frames_to_bytes(pcm, pcm->buffer_size),
914                                 PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, pcm->fd, 0);
915         if (pcm->mmap_buffer == MAP_FAILED) {
916             oops(pcm, -errno, "failed to mmap buffer %d bytes\n",
917                  pcm_frames_to_bytes(pcm, pcm->buffer_size));
918             goto fail_close;
919         }
920     }
921 
922     memset(&sparams, 0, sizeof(sparams));
923     sparams.tstamp_mode = SNDRV_PCM_TSTAMP_ENABLE;
924     sparams.period_step = 1;
925 
926     if (!config->start_threshold) {
927         if (pcm->flags & PCM_IN)
928             pcm->config.start_threshold = sparams.start_threshold = 1;
929         else
930             pcm->config.start_threshold = sparams.start_threshold =
931                 config->period_count * config->period_size / 2;
932     } else
933         sparams.start_threshold = config->start_threshold;
934 
935     /* pick a high stop threshold - todo: does this need further tuning */
936     if (!config->stop_threshold) {
937         if (pcm->flags & PCM_IN)
938             pcm->config.stop_threshold = sparams.stop_threshold =
939                 config->period_count * config->period_size * 10;
940         else
941             pcm->config.stop_threshold = sparams.stop_threshold =
942                 config->period_count * config->period_size;
943     }
944     else
945         sparams.stop_threshold = config->stop_threshold;
946 
947     if (!pcm->config.avail_min) {
948         if (pcm->flags & PCM_MMAP)
949             pcm->config.avail_min = sparams.avail_min = pcm->config.period_size;
950         else
951             pcm->config.avail_min = sparams.avail_min = 1;
952     } else
953         sparams.avail_min = config->avail_min;
954 
955     sparams.xfer_align = config->period_size / 2; /* needed for old kernels */
956     sparams.silence_size = 0;
957     sparams.silence_threshold = config->silence_threshold;
958     pcm->boundary = sparams.boundary = pcm->buffer_size;
959 
960     while (pcm->boundary * 2 <= INT_MAX - pcm->buffer_size)
961         pcm->boundary *= 2;
962 
963     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SW_PARAMS, &sparams)) {
964         oops(pcm, errno, "cannot set sw params");
965         goto fail;
966     }
967 
968     rc = pcm_hw_mmap_status(pcm);
969     if (rc < 0) {
970         oops(pcm, rc, "mmap status failed");
971         goto fail;
972     }
973 
974 #ifdef SNDRV_PCM_IOCTL_TTSTAMP
975     if (pcm->flags & PCM_MONOTONIC) {
976         int arg = SNDRV_PCM_TSTAMP_TYPE_MONOTONIC;
977         rc = ioctl(pcm->fd, SNDRV_PCM_IOCTL_TTSTAMP, &arg);
978         if (rc < 0) {
979             oops(pcm, rc, "cannot set timestamp type");
980             goto fail;
981         }
982     }
983 #endif
984 
985     pcm->underruns = 0;
986     return pcm;
987 
988 fail:
989     if (flags & PCM_MMAP)
990         munmap(pcm->mmap_buffer, pcm_frames_to_bytes(pcm, pcm->buffer_size));
991 fail_close:
992     close(pcm->fd);
993     pcm->fd = -1;
994     return pcm;
995 }
996 
pcm_is_ready(struct pcm * pcm)997 int pcm_is_ready(struct pcm *pcm)
998 {
999     return pcm->fd >= 0;
1000 }
1001 
pcm_prepare(struct pcm * pcm)1002 int pcm_prepare(struct pcm *pcm)
1003 {
1004     if (pcm->prepared)
1005         return 0;
1006 
1007     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_PREPARE) < 0)
1008         return oops(pcm, errno, "cannot prepare channel");
1009 
1010     pcm->prepared = 1;
1011     return 0;
1012 }
1013 
pcm_start(struct pcm * pcm)1014 int pcm_start(struct pcm *pcm)
1015 {
1016     int prepare_error = pcm_prepare(pcm);
1017     if (prepare_error)
1018         return prepare_error;
1019 
1020     if (pcm->flags & PCM_MMAP)
1021 	    pcm_sync_ptr(pcm, 0);
1022 
1023     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_START) < 0)
1024         return oops(pcm, errno, "cannot start channel");
1025 
1026     pcm->running = 1;
1027     return 0;
1028 }
1029 
pcm_stop(struct pcm * pcm)1030 int pcm_stop(struct pcm *pcm)
1031 {
1032     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_DROP) < 0)
1033         return oops(pcm, errno, "cannot stop channel");
1034 
1035     pcm->prepared = 0;
1036     pcm->running = 0;
1037     return 0;
1038 }
1039 
pcm_mmap_playback_avail(struct pcm * pcm)1040 static inline int pcm_mmap_playback_avail(struct pcm *pcm)
1041 {
1042     int avail;
1043 
1044     avail = pcm->mmap_status->hw_ptr + pcm->buffer_size - pcm->mmap_control->appl_ptr;
1045 
1046     if (avail < 0)
1047         avail += pcm->boundary;
1048     else if (avail > (int)pcm->boundary)
1049         avail -= pcm->boundary;
1050 
1051     return avail;
1052 }
1053 
pcm_mmap_capture_avail(struct pcm * pcm)1054 static inline int pcm_mmap_capture_avail(struct pcm *pcm)
1055 {
1056     int avail = pcm->mmap_status->hw_ptr - pcm->mmap_control->appl_ptr;
1057     if (avail < 0)
1058         avail += pcm->boundary;
1059     return avail;
1060 }
1061 
pcm_mmap_avail(struct pcm * pcm)1062 static inline int pcm_mmap_avail(struct pcm *pcm)
1063 {
1064     pcm_sync_ptr(pcm, SNDRV_PCM_SYNC_PTR_HWSYNC);
1065     if (pcm->flags & PCM_IN)
1066         return pcm_mmap_capture_avail(pcm);
1067     else
1068         return pcm_mmap_playback_avail(pcm);
1069 }
1070 
pcm_mmap_appl_forward(struct pcm * pcm,int frames)1071 static void pcm_mmap_appl_forward(struct pcm *pcm, int frames)
1072 {
1073     unsigned int appl_ptr = pcm->mmap_control->appl_ptr;
1074     appl_ptr += frames;
1075 
1076     /* check for boundary wrap */
1077     if (appl_ptr > pcm->boundary)
1078          appl_ptr -= pcm->boundary;
1079     pcm->mmap_control->appl_ptr = appl_ptr;
1080 }
1081 
pcm_mmap_begin(struct pcm * pcm,void ** areas,unsigned int * offset,unsigned int * frames)1082 int pcm_mmap_begin(struct pcm *pcm, void **areas, unsigned int *offset,
1083                    unsigned int *frames)
1084 {
1085     unsigned int continuous, copy_frames, avail;
1086 
1087     /* return the mmap buffer */
1088     *areas = pcm->mmap_buffer;
1089 
1090     /* and the application offset in frames */
1091     *offset = pcm->mmap_control->appl_ptr % pcm->buffer_size;
1092 
1093     avail = pcm_mmap_avail(pcm);
1094     if (avail > pcm->buffer_size)
1095         avail = pcm->buffer_size;
1096     continuous = pcm->buffer_size - *offset;
1097 
1098     /* we can only copy frames if the are availabale and continuos */
1099     copy_frames = *frames;
1100     if (copy_frames > avail)
1101         copy_frames = avail;
1102     if (copy_frames > continuous)
1103         copy_frames = continuous;
1104     *frames = copy_frames;
1105 
1106     return 0;
1107 }
1108 
pcm_mmap_commit(struct pcm * pcm,unsigned int offset,unsigned int frames)1109 int pcm_mmap_commit(struct pcm *pcm, unsigned int offset, unsigned int frames)
1110 {
1111     /* update the application pointer in userspace and kernel */
1112     pcm_mmap_appl_forward(pcm, frames);
1113     pcm_sync_ptr(pcm, 0);
1114 
1115     return frames;
1116 }
1117 
pcm_avail_update(struct pcm * pcm)1118 int pcm_avail_update(struct pcm *pcm)
1119 {
1120     pcm_sync_ptr(pcm, 0);
1121     return pcm_mmap_avail(pcm);
1122 }
1123 
pcm_state(struct pcm * pcm)1124 int pcm_state(struct pcm *pcm)
1125 {
1126     int err = pcm_sync_ptr(pcm, 0);
1127     if (err < 0)
1128         return err;
1129 
1130     return pcm->mmap_status->state;
1131 }
1132 
pcm_set_avail_min(struct pcm * pcm,int avail_min)1133 int pcm_set_avail_min(struct pcm *pcm, int avail_min)
1134 {
1135     if ((~pcm->flags) & (PCM_MMAP | PCM_NOIRQ))
1136         return -ENOSYS;
1137 
1138     pcm->config.avail_min = avail_min;
1139     return 0;
1140 }
1141 
pcm_wait(struct pcm * pcm,int timeout)1142 int pcm_wait(struct pcm *pcm, int timeout)
1143 {
1144     struct pollfd pfd;
1145     int err;
1146 
1147     pfd.fd = pcm->fd;
1148     pfd.events = POLLOUT | POLLERR | POLLNVAL;
1149 
1150     do {
1151         /* let's wait for avail or timeout */
1152         err = poll(&pfd, 1, timeout);
1153         if (err < 0)
1154             return -errno;
1155 
1156         /* timeout ? */
1157         if (err == 0)
1158             return 0;
1159 
1160         /* have we been interrupted ? */
1161         if (errno == -EINTR)
1162             continue;
1163 
1164         /* check for any errors */
1165         if (pfd.revents & (POLLERR | POLLNVAL)) {
1166             switch (pcm_state(pcm)) {
1167             case PCM_STATE_XRUN:
1168                 return -EPIPE;
1169             case PCM_STATE_SUSPENDED:
1170                 return -ESTRPIPE;
1171             case PCM_STATE_DISCONNECTED:
1172                 return -ENODEV;
1173             default:
1174                 return -EIO;
1175             }
1176         }
1177     /* poll again if fd not ready for IO */
1178     } while (!(pfd.revents & (POLLIN | POLLOUT)));
1179 
1180     return 1;
1181 }
1182 
pcm_mmap_transfer(struct pcm * pcm,const void * buffer,unsigned int bytes)1183 int pcm_mmap_transfer(struct pcm *pcm, const void *buffer, unsigned int bytes)
1184 {
1185     int err = 0, frames, avail;
1186     unsigned int offset = 0, count;
1187 
1188     if (bytes == 0)
1189         return 0;
1190 
1191     count = pcm_bytes_to_frames(pcm, bytes);
1192 
1193     while (count > 0) {
1194 
1195         /* get the available space for writing new frames */
1196         avail = pcm_avail_update(pcm);
1197         if (avail < 0) {
1198             fprintf(stderr, "cannot determine available mmap frames");
1199             return err;
1200         }
1201 
1202         /* start the audio if we reach the threshold */
1203 	    if (!pcm->running &&
1204             (pcm->buffer_size - avail) >= pcm->config.start_threshold) {
1205             if (pcm_start(pcm) < 0) {
1206                fprintf(stderr, "start error: hw 0x%x app 0x%x avail 0x%x\n",
1207                     (unsigned int)pcm->mmap_status->hw_ptr,
1208                     (unsigned int)pcm->mmap_control->appl_ptr,
1209                     avail);
1210                 return -errno;
1211             }
1212             pcm->wait_for_avail_min = 0;
1213         }
1214 
1215         /* sleep until we have space to write new frames */
1216         if (pcm->running) {
1217             /* enable waiting for avail_min threshold when less frames than we have to write
1218              * are available. */
1219             if (!pcm->wait_for_avail_min && (count > (unsigned int)avail))
1220                 pcm->wait_for_avail_min = 1;
1221 
1222             if (pcm->wait_for_avail_min && (avail < pcm->config.avail_min)) {
1223                 int time = -1;
1224 
1225                 /* disable waiting for avail_min threshold to allow small amounts of data to be
1226                  * written without waiting as long as there is enough room in buffer. */
1227                 pcm->wait_for_avail_min = 0;
1228 
1229                 if (pcm->flags & PCM_NOIRQ)
1230                     time = (pcm->config.avail_min - avail) / pcm->noirq_frames_per_msec;
1231 
1232                 err = pcm_wait(pcm, time);
1233                 if (err < 0) {
1234                     pcm->prepared = 0;
1235                     pcm->running = 0;
1236                     oops(pcm, err, "wait error: hw 0x%x app 0x%x avail 0x%x\n",
1237                         (unsigned int)pcm->mmap_status->hw_ptr,
1238                         (unsigned int)pcm->mmap_control->appl_ptr,
1239                         avail);
1240                     pcm->mmap_control->appl_ptr = 0;
1241                     return err;
1242                 }
1243                 continue;
1244             }
1245         }
1246 
1247         frames = count;
1248         if (frames > avail)
1249             frames = avail;
1250 
1251         if (!frames)
1252             break;
1253 
1254         /* copy frames from buffer */
1255         frames = pcm_mmap_transfer_areas(pcm, (void *)buffer, offset, frames);
1256         if (frames < 0) {
1257             fprintf(stderr, "write error: hw 0x%x app 0x%x avail 0x%x\n",
1258                     (unsigned int)pcm->mmap_status->hw_ptr,
1259                     (unsigned int)pcm->mmap_control->appl_ptr,
1260                     avail);
1261             return frames;
1262         }
1263 
1264         offset += frames;
1265         count -= frames;
1266     }
1267 
1268     return 0;
1269 }
1270 
pcm_mmap_write(struct pcm * pcm,const void * data,unsigned int count)1271 int pcm_mmap_write(struct pcm *pcm, const void *data, unsigned int count)
1272 {
1273     if ((~pcm->flags) & (PCM_OUT | PCM_MMAP))
1274         return -ENOSYS;
1275 
1276     return pcm_mmap_transfer(pcm, (void *)data, count);
1277 }
1278 
pcm_mmap_read(struct pcm * pcm,void * data,unsigned int count)1279 int pcm_mmap_read(struct pcm *pcm, void *data, unsigned int count)
1280 {
1281     if ((~pcm->flags) & (PCM_IN | PCM_MMAP))
1282         return -ENOSYS;
1283 
1284     return pcm_mmap_transfer(pcm, data, count);
1285 }
1286 
pcm_ioctl(struct pcm * pcm,int request,...)1287 int pcm_ioctl(struct pcm *pcm, int request, ...)
1288 {
1289     va_list ap;
1290     void * arg;
1291 
1292     if (!pcm_is_ready(pcm))
1293         return -1;
1294 
1295     va_start(ap, request);
1296     arg = va_arg(ap, void *);
1297     va_end(ap);
1298 
1299     return ioctl(pcm->fd, request, arg);
1300 }
1301