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 
53 /* Logs information into a string; follows snprintf() in that
54  * offset may be greater than size, and though no characters are copied
55  * into string, characters are still counted into offset. */
56 #define STRLOG(string, offset, size, ...) \
57     do { int temp, clipoffset = offset > size ? size : offset; \
58          temp = snprintf(string + clipoffset, size - clipoffset, __VA_ARGS__); \
59          if (temp > 0) offset += temp; } while (0)
60 
61 #ifndef ARRAY_SIZE
62 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
63 #endif
64 
65 /* refer to SNDRV_PCM_ACCESS_##index in sound/asound.h. */
66 static const char * const access_lookup[] = {
67         "MMAP_INTERLEAVED",
68         "MMAP_NONINTERLEAVED",
69         "MMAP_COMPLEX",
70         "RW_INTERLEAVED",
71         "RW_NONINTERLEAVED",
72 };
73 
74 /* refer to SNDRV_PCM_FORMAT_##index in sound/asound.h. */
75 static const char * const format_lookup[] = {
76         /*[0] =*/ "S8",
77         "U8",
78         "S16_LE",
79         "S16_BE",
80         "U16_LE",
81         "U16_BE",
82         "S24_LE",
83         "S24_BE",
84         "U24_LE",
85         "U24_BE",
86         "S32_LE",
87         "S32_BE",
88         "U32_LE",
89         "U32_BE",
90         "FLOAT_LE",
91         "FLOAT_BE",
92         "FLOAT64_LE",
93         "FLOAT64_BE",
94         "IEC958_SUBFRAME_LE",
95         "IEC958_SUBFRAME_BE",
96         "MU_LAW",
97         "A_LAW",
98         "IMA_ADPCM",
99         "MPEG",
100         /*[24] =*/ "GSM",
101         /* gap */
102         [31] = "SPECIAL",
103         "S24_3LE",
104         "S24_3BE",
105         "U24_3LE",
106         "U24_3BE",
107         "S20_3LE",
108         "S20_3BE",
109         "U20_3LE",
110         "U20_3BE",
111         "S18_3LE",
112         "S18_3BE",
113         "U18_3LE",
114         /*[43] =*/ "U18_3BE",
115 #if 0
116         /* recent additions, may not be present on local asound.h */
117         "G723_24",
118         "G723_24_1B",
119         "G723_40",
120         "G723_40_1B",
121         "DSD_U8",
122         "DSD_U16_LE",
123 #endif
124 };
125 
126 /* refer to SNDRV_PCM_SUBFORMAT_##index in sound/asound.h. */
127 static const char * const subformat_lookup[] = {
128         "STD",
129 };
130 
param_is_mask(int p)131 static inline int param_is_mask(int p)
132 {
133     return (p >= SNDRV_PCM_HW_PARAM_FIRST_MASK) &&
134         (p <= SNDRV_PCM_HW_PARAM_LAST_MASK);
135 }
136 
param_is_interval(int p)137 static inline int param_is_interval(int p)
138 {
139     return (p >= SNDRV_PCM_HW_PARAM_FIRST_INTERVAL) &&
140         (p <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL);
141 }
142 
param_to_interval(struct snd_pcm_hw_params * p,int n)143 static inline struct snd_interval *param_to_interval(struct snd_pcm_hw_params *p, int n)
144 {
145     return &(p->intervals[n - SNDRV_PCM_HW_PARAM_FIRST_INTERVAL]);
146 }
147 
param_to_mask(struct snd_pcm_hw_params * p,int n)148 static inline struct snd_mask *param_to_mask(struct snd_pcm_hw_params *p, int n)
149 {
150     return &(p->masks[n - SNDRV_PCM_HW_PARAM_FIRST_MASK]);
151 }
152 
param_set_mask(struct snd_pcm_hw_params * p,int n,unsigned int bit)153 static void param_set_mask(struct snd_pcm_hw_params *p, int n, unsigned int bit)
154 {
155     if (bit >= SNDRV_MASK_MAX)
156         return;
157     if (param_is_mask(n)) {
158         struct snd_mask *m = param_to_mask(p, n);
159         m->bits[0] = 0;
160         m->bits[1] = 0;
161         m->bits[bit >> 5] |= (1 << (bit & 31));
162     }
163 }
164 
param_set_min(struct snd_pcm_hw_params * p,int n,unsigned int val)165 static void param_set_min(struct snd_pcm_hw_params *p, int n, unsigned int val)
166 {
167     if (param_is_interval(n)) {
168         struct snd_interval *i = param_to_interval(p, n);
169         i->min = val;
170     }
171 }
172 
param_get_min(struct snd_pcm_hw_params * p,int n)173 static unsigned int param_get_min(struct snd_pcm_hw_params *p, int n)
174 {
175     if (param_is_interval(n)) {
176         struct snd_interval *i = param_to_interval(p, n);
177         return i->min;
178     }
179     return 0;
180 }
181 
param_set_max(struct snd_pcm_hw_params * p,int n,unsigned int val)182 static void param_set_max(struct snd_pcm_hw_params *p, int n, unsigned int val)
183 {
184     if (param_is_interval(n)) {
185         struct snd_interval *i = param_to_interval(p, n);
186         i->max = val;
187     }
188 }
189 
param_get_max(struct snd_pcm_hw_params * p,int n)190 static unsigned int param_get_max(struct snd_pcm_hw_params *p, int n)
191 {
192     if (param_is_interval(n)) {
193         struct snd_interval *i = param_to_interval(p, n);
194         return i->max;
195     }
196     return 0;
197 }
198 
param_set_int(struct snd_pcm_hw_params * p,int n,unsigned int val)199 static void param_set_int(struct snd_pcm_hw_params *p, int n, unsigned int val)
200 {
201     if (param_is_interval(n)) {
202         struct snd_interval *i = param_to_interval(p, n);
203         i->min = val;
204         i->max = val;
205         i->integer = 1;
206     }
207 }
208 
param_get_int(struct snd_pcm_hw_params * p,int n)209 static unsigned int param_get_int(struct snd_pcm_hw_params *p, int n)
210 {
211     if (param_is_interval(n)) {
212         struct snd_interval *i = param_to_interval(p, n);
213         if (i->integer)
214             return i->max;
215     }
216     return 0;
217 }
218 
param_init(struct snd_pcm_hw_params * p)219 static void param_init(struct snd_pcm_hw_params *p)
220 {
221     int n;
222 
223     memset(p, 0, sizeof(*p));
224     for (n = SNDRV_PCM_HW_PARAM_FIRST_MASK;
225          n <= SNDRV_PCM_HW_PARAM_LAST_MASK; n++) {
226             struct snd_mask *m = param_to_mask(p, n);
227             m->bits[0] = ~0;
228             m->bits[1] = ~0;
229     }
230     for (n = SNDRV_PCM_HW_PARAM_FIRST_INTERVAL;
231          n <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; n++) {
232             struct snd_interval *i = param_to_interval(p, n);
233             i->min = 0;
234             i->max = ~0;
235     }
236     p->rmask = ~0U;
237     p->cmask = 0;
238     p->info = ~0U;
239 }
240 
241 #define PCM_ERROR_MAX 128
242 
243 struct pcm {
244     int fd;
245     unsigned int flags;
246     int running:1;
247     int prepared:1;
248     int underruns;
249     unsigned int buffer_size;
250     unsigned int boundary;
251     char error[PCM_ERROR_MAX];
252     struct pcm_config config;
253     struct snd_pcm_mmap_status *mmap_status;
254     struct snd_pcm_mmap_control *mmap_control;
255     struct snd_pcm_sync_ptr *sync_ptr;
256     void *mmap_buffer;
257     unsigned int noirq_frames_per_msec;
258     int wait_for_avail_min;
259 };
260 
pcm_get_buffer_size(struct pcm * pcm)261 unsigned int pcm_get_buffer_size(struct pcm *pcm)
262 {
263     return pcm->buffer_size;
264 }
265 
pcm_get_error(struct pcm * pcm)266 const char* pcm_get_error(struct pcm *pcm)
267 {
268     return pcm->error;
269 }
270 
oops(struct pcm * pcm,int e,const char * fmt,...)271 static int oops(struct pcm *pcm, int e, const char *fmt, ...)
272 {
273     va_list ap;
274     int sz;
275 
276     va_start(ap, fmt);
277     vsnprintf(pcm->error, PCM_ERROR_MAX, fmt, ap);
278     va_end(ap);
279     sz = strlen(pcm->error);
280 
281     if (errno)
282         snprintf(pcm->error + sz, PCM_ERROR_MAX - sz,
283                  ": %s", strerror(e));
284     return -1;
285 }
286 
pcm_format_to_alsa(enum pcm_format format)287 static unsigned int pcm_format_to_alsa(enum pcm_format format)
288 {
289     switch (format) {
290     case PCM_FORMAT_S32_LE:
291         return SNDRV_PCM_FORMAT_S32_LE;
292     case PCM_FORMAT_S8:
293         return SNDRV_PCM_FORMAT_S8;
294     case PCM_FORMAT_S24_3LE:
295         return SNDRV_PCM_FORMAT_S24_3LE;
296     case PCM_FORMAT_S24_LE:
297         return SNDRV_PCM_FORMAT_S24_LE;
298     default:
299     case PCM_FORMAT_S16_LE:
300         return SNDRV_PCM_FORMAT_S16_LE;
301     };
302 }
303 
pcm_format_to_bits(enum pcm_format format)304 unsigned int pcm_format_to_bits(enum pcm_format format)
305 {
306     switch (format) {
307     case PCM_FORMAT_S32_LE:
308     case PCM_FORMAT_S24_LE:
309         return 32;
310     case PCM_FORMAT_S24_3LE:
311         return 24;
312     default:
313     case PCM_FORMAT_S16_LE:
314         return 16;
315     };
316 }
317 
pcm_bytes_to_frames(struct pcm * pcm,unsigned int bytes)318 unsigned int pcm_bytes_to_frames(struct pcm *pcm, unsigned int bytes)
319 {
320     return bytes / (pcm->config.channels *
321         (pcm_format_to_bits(pcm->config.format) >> 3));
322 }
323 
pcm_frames_to_bytes(struct pcm * pcm,unsigned int frames)324 unsigned int pcm_frames_to_bytes(struct pcm *pcm, unsigned int frames)
325 {
326     return frames * pcm->config.channels *
327         (pcm_format_to_bits(pcm->config.format) >> 3);
328 }
329 
pcm_sync_ptr(struct pcm * pcm,int flags)330 static int pcm_sync_ptr(struct pcm *pcm, int flags) {
331     if (pcm->sync_ptr) {
332         pcm->sync_ptr->flags = flags;
333         if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SYNC_PTR, pcm->sync_ptr) < 0)
334             return -1;
335     }
336     return 0;
337 }
338 
pcm_hw_mmap_status(struct pcm * pcm)339 static int pcm_hw_mmap_status(struct pcm *pcm) {
340 
341     if (pcm->sync_ptr)
342         return 0;
343 
344     int page_size = sysconf(_SC_PAGE_SIZE);
345     pcm->mmap_status = mmap(NULL, page_size, PROT_READ, MAP_FILE | MAP_SHARED,
346                             pcm->fd, SNDRV_PCM_MMAP_OFFSET_STATUS);
347     if (pcm->mmap_status == MAP_FAILED)
348         pcm->mmap_status = NULL;
349     if (!pcm->mmap_status)
350         goto mmap_error;
351 
352     pcm->mmap_control = mmap(NULL, page_size, PROT_READ | PROT_WRITE,
353                              MAP_FILE | MAP_SHARED, pcm->fd, SNDRV_PCM_MMAP_OFFSET_CONTROL);
354     if (pcm->mmap_control == MAP_FAILED)
355         pcm->mmap_control = NULL;
356     if (!pcm->mmap_control) {
357         munmap(pcm->mmap_status, page_size);
358         pcm->mmap_status = NULL;
359         goto mmap_error;
360     }
361     if (pcm->flags & PCM_MMAP)
362         pcm->mmap_control->avail_min = pcm->config.avail_min;
363     else
364         pcm->mmap_control->avail_min = 1;
365 
366     return 0;
367 
368 mmap_error:
369 
370     pcm->sync_ptr = calloc(1, sizeof(*pcm->sync_ptr));
371     if (!pcm->sync_ptr)
372         return -ENOMEM;
373     pcm->mmap_status = &pcm->sync_ptr->s.status;
374     pcm->mmap_control = &pcm->sync_ptr->c.control;
375     if (pcm->flags & PCM_MMAP)
376         pcm->mmap_control->avail_min = pcm->config.avail_min;
377     else
378         pcm->mmap_control->avail_min = 1;
379 
380     pcm_sync_ptr(pcm, 0);
381 
382     return 0;
383 }
384 
pcm_hw_munmap_status(struct pcm * pcm)385 static void pcm_hw_munmap_status(struct pcm *pcm) {
386     if (pcm->sync_ptr) {
387         free(pcm->sync_ptr);
388         pcm->sync_ptr = NULL;
389     } else {
390         int page_size = sysconf(_SC_PAGE_SIZE);
391         if (pcm->mmap_status)
392             munmap(pcm->mmap_status, page_size);
393         if (pcm->mmap_control)
394             munmap(pcm->mmap_control, page_size);
395     }
396     pcm->mmap_status = NULL;
397     pcm->mmap_control = NULL;
398 }
399 
pcm_areas_copy(struct pcm * pcm,unsigned int pcm_offset,char * buf,unsigned int src_offset,unsigned int frames)400 static int pcm_areas_copy(struct pcm *pcm, unsigned int pcm_offset,
401                           char *buf, unsigned int src_offset,
402                           unsigned int frames)
403 {
404     int size_bytes = pcm_frames_to_bytes(pcm, frames);
405     int pcm_offset_bytes = pcm_frames_to_bytes(pcm, pcm_offset);
406     int src_offset_bytes = pcm_frames_to_bytes(pcm, src_offset);
407 
408     /* interleaved only atm */
409     if (pcm->flags & PCM_IN)
410         memcpy(buf + src_offset_bytes,
411                (char*)pcm->mmap_buffer + pcm_offset_bytes,
412                size_bytes);
413     else
414         memcpy((char*)pcm->mmap_buffer + pcm_offset_bytes,
415                buf + src_offset_bytes,
416                size_bytes);
417     return 0;
418 }
419 
pcm_mmap_transfer_areas(struct pcm * pcm,char * buf,unsigned int offset,unsigned int size)420 static int pcm_mmap_transfer_areas(struct pcm *pcm, char *buf,
421                                 unsigned int offset, unsigned int size)
422 {
423     void *pcm_areas;
424     int commit;
425     unsigned int pcm_offset, frames, count = 0;
426 
427     while (size > 0) {
428         frames = size;
429         pcm_mmap_begin(pcm, &pcm_areas, &pcm_offset, &frames);
430         pcm_areas_copy(pcm, pcm_offset, buf, offset, frames);
431         commit = pcm_mmap_commit(pcm, pcm_offset, frames);
432         if (commit < 0) {
433             oops(pcm, commit, "failed to commit %d frames\n", frames);
434             return commit;
435         }
436 
437         offset += commit;
438         count += commit;
439         size -= commit;
440     }
441     return count;
442 }
443 
pcm_get_htimestamp(struct pcm * pcm,unsigned int * avail,struct timespec * tstamp)444 int pcm_get_htimestamp(struct pcm *pcm, unsigned int *avail,
445                        struct timespec *tstamp)
446 {
447     int frames;
448     int rc;
449     snd_pcm_uframes_t hw_ptr;
450 
451     if (!pcm_is_ready(pcm))
452         return -1;
453 
454     rc = pcm_sync_ptr(pcm, SNDRV_PCM_SYNC_PTR_APPL|SNDRV_PCM_SYNC_PTR_HWSYNC);
455     if (rc < 0)
456         return -1;
457 
458     if ((pcm->mmap_status->state != PCM_STATE_RUNNING) &&
459             (pcm->mmap_status->state != PCM_STATE_DRAINING))
460         return -1;
461 
462     *tstamp = pcm->mmap_status->tstamp;
463     if (tstamp->tv_sec == 0 && tstamp->tv_nsec == 0)
464         return -1;
465 
466     hw_ptr = pcm->mmap_status->hw_ptr;
467     if (pcm->flags & PCM_IN)
468         frames = hw_ptr - pcm->mmap_control->appl_ptr;
469     else
470         frames = hw_ptr + pcm->buffer_size - pcm->mmap_control->appl_ptr;
471 
472     if (frames < 0)
473         frames += pcm->boundary;
474     else if (frames > (int)pcm->boundary)
475         frames -= pcm->boundary;
476 
477     *avail = (unsigned int)frames;
478 
479     return 0;
480 }
481 
pcm_write(struct pcm * pcm,const void * data,unsigned int count)482 int pcm_write(struct pcm *pcm, const void *data, unsigned int count)
483 {
484     struct snd_xferi x;
485 
486     if (pcm->flags & PCM_IN)
487         return -EINVAL;
488 
489     x.buf = (void*)data;
490     x.frames = count / (pcm->config.channels *
491                         pcm_format_to_bits(pcm->config.format) / 8);
492 
493     for (;;) {
494         if (!pcm->running) {
495             int prepare_error = pcm_prepare(pcm);
496             if (prepare_error)
497                 return prepare_error;
498             if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_WRITEI_FRAMES, &x))
499                 return oops(pcm, errno, "cannot write initial data");
500             pcm->running = 1;
501             return 0;
502         }
503         if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_WRITEI_FRAMES, &x)) {
504             pcm->prepared = 0;
505             pcm->running = 0;
506             if (errno == EPIPE) {
507                 /* we failed to make our window -- try to restart if we are
508                  * allowed to do so.  Otherwise, simply allow the EPIPE error to
509                  * propagate up to the app level */
510                 pcm->underruns++;
511                 if (pcm->flags & PCM_NORESTART)
512                     return -EPIPE;
513                 continue;
514             }
515             return oops(pcm, errno, "cannot write stream data");
516         }
517         return 0;
518     }
519 }
520 
pcm_read(struct pcm * pcm,void * data,unsigned int count)521 int pcm_read(struct pcm *pcm, void *data, unsigned int count)
522 {
523     struct snd_xferi x;
524 
525     if (!(pcm->flags & PCM_IN))
526         return -EINVAL;
527 
528     x.buf = data;
529     x.frames = count / (pcm->config.channels *
530                         pcm_format_to_bits(pcm->config.format) / 8);
531 
532     for (;;) {
533         if (!pcm->running) {
534             if (pcm_start(pcm) < 0) {
535                 fprintf(stderr, "start error");
536                 return -errno;
537             }
538         }
539         if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_READI_FRAMES, &x)) {
540             pcm->prepared = 0;
541             pcm->running = 0;
542             if (errno == EPIPE) {
543                     /* we failed to make our window -- try to restart */
544                 pcm->underruns++;
545                 continue;
546             }
547             return oops(pcm, errno, "cannot read stream data");
548         }
549         return 0;
550     }
551 }
552 
553 static struct pcm bad_pcm = {
554     .fd = -1,
555 };
556 
pcm_params_get(unsigned int card,unsigned int device,unsigned int flags)557 struct pcm_params *pcm_params_get(unsigned int card, unsigned int device,
558                                   unsigned int flags)
559 {
560     struct snd_pcm_hw_params *params;
561     char fn[256];
562     int fd;
563 
564     snprintf(fn, sizeof(fn), "/dev/snd/pcmC%uD%u%c", card, device,
565              flags & PCM_IN ? 'c' : 'p');
566 
567     fd = open(fn, O_RDWR);
568     if (fd < 0) {
569         fprintf(stderr, "cannot open device '%s'\n", fn);
570         goto err_open;
571     }
572 
573     params = calloc(1, sizeof(struct snd_pcm_hw_params));
574     if (!params)
575         goto err_calloc;
576 
577     param_init(params);
578     if (ioctl(fd, SNDRV_PCM_IOCTL_HW_REFINE, params)) {
579         fprintf(stderr, "SNDRV_PCM_IOCTL_HW_REFINE error (%d)\n", errno);
580         goto err_hw_refine;
581     }
582 
583     close(fd);
584 
585     return (struct pcm_params *)params;
586 
587 err_hw_refine:
588     free(params);
589 err_calloc:
590     close(fd);
591 err_open:
592     return NULL;
593 }
594 
pcm_params_free(struct pcm_params * pcm_params)595 void pcm_params_free(struct pcm_params *pcm_params)
596 {
597     struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params;
598 
599     if (params)
600         free(params);
601 }
602 
pcm_param_to_alsa(enum pcm_param param)603 static int pcm_param_to_alsa(enum pcm_param param)
604 {
605     switch (param) {
606     case PCM_PARAM_ACCESS:
607         return SNDRV_PCM_HW_PARAM_ACCESS;
608     case PCM_PARAM_FORMAT:
609         return SNDRV_PCM_HW_PARAM_FORMAT;
610     case PCM_PARAM_SUBFORMAT:
611         return SNDRV_PCM_HW_PARAM_SUBFORMAT;
612     case PCM_PARAM_SAMPLE_BITS:
613         return SNDRV_PCM_HW_PARAM_SAMPLE_BITS;
614         break;
615     case PCM_PARAM_FRAME_BITS:
616         return SNDRV_PCM_HW_PARAM_FRAME_BITS;
617         break;
618     case PCM_PARAM_CHANNELS:
619         return SNDRV_PCM_HW_PARAM_CHANNELS;
620         break;
621     case PCM_PARAM_RATE:
622         return SNDRV_PCM_HW_PARAM_RATE;
623         break;
624     case PCM_PARAM_PERIOD_TIME:
625         return SNDRV_PCM_HW_PARAM_PERIOD_TIME;
626         break;
627     case PCM_PARAM_PERIOD_SIZE:
628         return SNDRV_PCM_HW_PARAM_PERIOD_SIZE;
629         break;
630     case PCM_PARAM_PERIOD_BYTES:
631         return SNDRV_PCM_HW_PARAM_PERIOD_BYTES;
632         break;
633     case PCM_PARAM_PERIODS:
634         return SNDRV_PCM_HW_PARAM_PERIODS;
635         break;
636     case PCM_PARAM_BUFFER_TIME:
637         return SNDRV_PCM_HW_PARAM_BUFFER_TIME;
638         break;
639     case PCM_PARAM_BUFFER_SIZE:
640         return SNDRV_PCM_HW_PARAM_BUFFER_SIZE;
641         break;
642     case PCM_PARAM_BUFFER_BYTES:
643         return SNDRV_PCM_HW_PARAM_BUFFER_BYTES;
644         break;
645     case PCM_PARAM_TICK_TIME:
646         return SNDRV_PCM_HW_PARAM_TICK_TIME;
647         break;
648 
649     default:
650         return -1;
651     }
652 }
653 
pcm_params_get_mask(struct pcm_params * pcm_params,enum pcm_param param)654 struct pcm_mask *pcm_params_get_mask(struct pcm_params *pcm_params,
655                                      enum pcm_param param)
656 {
657     int p;
658     struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params;
659     if (params == NULL) {
660         return NULL;
661     }
662 
663     p = pcm_param_to_alsa(param);
664     if (p < 0 || !param_is_mask(p)) {
665         return NULL;
666     }
667 
668     return (struct pcm_mask *)param_to_mask(params, p);
669 }
670 
pcm_params_get_min(struct pcm_params * pcm_params,enum pcm_param param)671 unsigned int pcm_params_get_min(struct pcm_params *pcm_params,
672                                 enum pcm_param param)
673 {
674     struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params;
675     int p;
676 
677     if (!params)
678         return 0;
679 
680     p = pcm_param_to_alsa(param);
681     if (p < 0)
682         return 0;
683 
684     return param_get_min(params, p);
685 }
686 
pcm_params_set_min(struct pcm_params * pcm_params,enum pcm_param param,unsigned int val)687 void pcm_params_set_min(struct pcm_params *pcm_params,
688                                 enum pcm_param param, unsigned int val)
689 {
690     struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params;
691     int p;
692 
693     if (!params)
694         return;
695 
696     p = pcm_param_to_alsa(param);
697     if (p < 0)
698         return;
699 
700     param_set_min(params, p, val);
701 }
702 
pcm_params_get_max(struct pcm_params * pcm_params,enum pcm_param param)703 unsigned int pcm_params_get_max(struct pcm_params *pcm_params,
704                                 enum pcm_param param)
705 {
706     struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params;
707     int p;
708 
709     if (!params)
710         return 0;
711 
712     p = pcm_param_to_alsa(param);
713     if (p < 0)
714         return 0;
715 
716     return param_get_max(params, p);
717 }
718 
pcm_params_set_max(struct pcm_params * pcm_params,enum pcm_param param,unsigned int val)719 void pcm_params_set_max(struct pcm_params *pcm_params,
720                                 enum pcm_param param, unsigned int val)
721 {
722     struct snd_pcm_hw_params *params = (struct snd_pcm_hw_params *)pcm_params;
723     int p;
724 
725     if (!params)
726         return;
727 
728     p = pcm_param_to_alsa(param);
729     if (p < 0)
730         return;
731 
732     param_set_max(params, p, val);
733 }
734 
pcm_mask_test(struct pcm_mask * m,unsigned int index)735 static int pcm_mask_test(struct pcm_mask *m, unsigned int index)
736 {
737     const unsigned int bitshift = 5; /* for 32 bit integer */
738     const unsigned int bitmask = (1 << bitshift) - 1;
739     unsigned int element;
740 
741     element = index >> bitshift;
742     if (element >= ARRAY_SIZE(m->bits))
743         return 0; /* for safety, but should never occur */
744     return (m->bits[element] >> (index & bitmask)) & 1;
745 }
746 
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)747 static int pcm_mask_to_string(struct pcm_mask *m, char *string, unsigned int size,
748                               char *mask_name,
749                               const char * const *bit_array_name, size_t bit_array_size)
750 {
751     unsigned int i;
752     unsigned int offset = 0;
753 
754     if (m == NULL)
755         return 0;
756     if (bit_array_size < 32) {
757         STRLOG(string, offset, size, "%12s:\t%#08x\n", mask_name, m->bits[0]);
758     } else { /* spans two or more bitfields, print with an array index */
759         for (i = 0; i < (bit_array_size + 31) >> 5; ++i) {
760             STRLOG(string, offset, size, "%9s[%d]:\t%#08x\n",
761                    mask_name, i, m->bits[i]);
762         }
763     }
764     for (i = 0; i < bit_array_size; ++i) {
765         if (pcm_mask_test(m, i)) {
766             STRLOG(string, offset, size, "%12s \t%s\n", "", bit_array_name[i]);
767         }
768     }
769     return offset;
770 }
771 
pcm_params_to_string(struct pcm_params * params,char * string,unsigned int size)772 int pcm_params_to_string(struct pcm_params *params, char *string, unsigned int size)
773 {
774     struct pcm_mask *m;
775     unsigned int min, max;
776     unsigned int clipoffset, offset;
777 
778     m = pcm_params_get_mask(params, PCM_PARAM_ACCESS);
779     offset = pcm_mask_to_string(m, string, size,
780                                  "Access", access_lookup, ARRAY_SIZE(access_lookup));
781     m = pcm_params_get_mask(params, PCM_PARAM_FORMAT);
782     clipoffset = offset > size ? size : offset;
783     offset += pcm_mask_to_string(m, string + clipoffset, size - clipoffset,
784                                  "Format", format_lookup, ARRAY_SIZE(format_lookup));
785     m = pcm_params_get_mask(params, PCM_PARAM_SUBFORMAT);
786     clipoffset = offset > size ? size : offset;
787     offset += pcm_mask_to_string(m, string + clipoffset, size - clipoffset,
788                                  "Subformat", subformat_lookup, ARRAY_SIZE(subformat_lookup));
789     min = pcm_params_get_min(params, PCM_PARAM_RATE);
790     max = pcm_params_get_max(params, PCM_PARAM_RATE);
791     STRLOG(string, offset, size, "        Rate:\tmin=%uHz\tmax=%uHz\n", min, max);
792     min = pcm_params_get_min(params, PCM_PARAM_CHANNELS);
793     max = pcm_params_get_max(params, PCM_PARAM_CHANNELS);
794     STRLOG(string, offset, size, "    Channels:\tmin=%u\t\tmax=%u\n", min, max);
795     min = pcm_params_get_min(params, PCM_PARAM_SAMPLE_BITS);
796     max = pcm_params_get_max(params, PCM_PARAM_SAMPLE_BITS);
797     STRLOG(string, offset, size, " Sample bits:\tmin=%u\t\tmax=%u\n", min, max);
798     min = pcm_params_get_min(params, PCM_PARAM_PERIOD_SIZE);
799     max = pcm_params_get_max(params, PCM_PARAM_PERIOD_SIZE);
800     STRLOG(string, offset, size, " Period size:\tmin=%u\t\tmax=%u\n", min, max);
801     min = pcm_params_get_min(params, PCM_PARAM_PERIODS);
802     max = pcm_params_get_max(params, PCM_PARAM_PERIODS);
803     STRLOG(string, offset, size, "Period count:\tmin=%u\t\tmax=%u\n", min, max);
804     return offset;
805 }
806 
pcm_params_format_test(struct pcm_params * params,enum pcm_format format)807 int pcm_params_format_test(struct pcm_params *params, enum pcm_format format)
808 {
809     unsigned int alsa_format = pcm_format_to_alsa(format);
810 
811     if (alsa_format == SNDRV_PCM_FORMAT_S16_LE && format != PCM_FORMAT_S16_LE)
812         return 0; /* caution: format not recognized is equivalent to S16_LE */
813     return pcm_mask_test(pcm_params_get_mask(params, PCM_PARAM_FORMAT), alsa_format);
814 }
815 
pcm_close(struct pcm * pcm)816 int pcm_close(struct pcm *pcm)
817 {
818     if (pcm == &bad_pcm)
819         return 0;
820 
821     pcm_hw_munmap_status(pcm);
822 
823     if (pcm->flags & PCM_MMAP) {
824         pcm_stop(pcm);
825         munmap(pcm->mmap_buffer, pcm_frames_to_bytes(pcm, pcm->buffer_size));
826     }
827 
828     if (pcm->fd >= 0)
829         close(pcm->fd);
830     pcm->prepared = 0;
831     pcm->running = 0;
832     pcm->buffer_size = 0;
833     pcm->fd = -1;
834     free(pcm);
835     return 0;
836 }
837 
pcm_open(unsigned int card,unsigned int device,unsigned int flags,struct pcm_config * config)838 struct pcm *pcm_open(unsigned int card, unsigned int device,
839                      unsigned int flags, struct pcm_config *config)
840 {
841     struct pcm *pcm;
842     struct snd_pcm_info info;
843     struct snd_pcm_hw_params params;
844     struct snd_pcm_sw_params sparams;
845     char fn[256];
846     int rc;
847 
848     pcm = calloc(1, sizeof(struct pcm));
849     if (!pcm || !config)
850         return &bad_pcm; /* TODO: could support default config here */
851 
852     pcm->config = *config;
853 
854     snprintf(fn, sizeof(fn), "/dev/snd/pcmC%uD%u%c", card, device,
855              flags & PCM_IN ? 'c' : 'p');
856 
857     pcm->flags = flags;
858     pcm->fd = open(fn, O_RDWR);
859     if (pcm->fd < 0) {
860         oops(pcm, errno, "cannot open device '%s'", fn);
861         return pcm;
862     }
863 
864     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_INFO, &info)) {
865         oops(pcm, errno, "cannot get info");
866         goto fail_close;
867     }
868 
869     param_init(&params);
870     param_set_mask(&params, SNDRV_PCM_HW_PARAM_FORMAT,
871                    pcm_format_to_alsa(config->format));
872     param_set_mask(&params, SNDRV_PCM_HW_PARAM_SUBFORMAT,
873                    SNDRV_PCM_SUBFORMAT_STD);
874     param_set_min(&params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, config->period_size);
875     param_set_int(&params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS,
876                   pcm_format_to_bits(config->format));
877     param_set_int(&params, SNDRV_PCM_HW_PARAM_FRAME_BITS,
878                   pcm_format_to_bits(config->format) * config->channels);
879     param_set_int(&params, SNDRV_PCM_HW_PARAM_CHANNELS,
880                   config->channels);
881     param_set_int(&params, SNDRV_PCM_HW_PARAM_PERIODS, config->period_count);
882     param_set_int(&params, SNDRV_PCM_HW_PARAM_RATE, config->rate);
883 
884     if (flags & PCM_NOIRQ) {
885         if (!(flags & PCM_MMAP)) {
886             oops(pcm, -EINVAL, "noirq only currently supported with mmap().");
887             goto fail;
888         }
889 
890         params.flags |= SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP;
891         pcm->noirq_frames_per_msec = config->rate / 1000;
892     }
893 
894     if (flags & PCM_MMAP)
895         param_set_mask(&params, SNDRV_PCM_HW_PARAM_ACCESS,
896                        SNDRV_PCM_ACCESS_MMAP_INTERLEAVED);
897     else
898         param_set_mask(&params, SNDRV_PCM_HW_PARAM_ACCESS,
899                        SNDRV_PCM_ACCESS_RW_INTERLEAVED);
900 
901     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_HW_PARAMS, &params)) {
902         oops(pcm, errno, "cannot set hw params");
903         goto fail_close;
904     }
905 
906     /* get our refined hw_params */
907     config->period_size = param_get_int(&params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
908     config->period_count = param_get_int(&params, SNDRV_PCM_HW_PARAM_PERIODS);
909     pcm->buffer_size = config->period_count * config->period_size;
910 
911     if (flags & PCM_MMAP) {
912         pcm->mmap_buffer = mmap(NULL, pcm_frames_to_bytes(pcm, pcm->buffer_size),
913                                 PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, pcm->fd, 0);
914         if (pcm->mmap_buffer == MAP_FAILED) {
915             oops(pcm, -errno, "failed to mmap buffer %d bytes\n",
916                  pcm_frames_to_bytes(pcm, pcm->buffer_size));
917             goto fail_close;
918         }
919     }
920 
921     memset(&sparams, 0, sizeof(sparams));
922     sparams.tstamp_mode = SNDRV_PCM_TSTAMP_ENABLE;
923     sparams.period_step = 1;
924 
925     if (!config->start_threshold) {
926         if (pcm->flags & PCM_IN)
927             pcm->config.start_threshold = sparams.start_threshold = 1;
928         else
929             pcm->config.start_threshold = sparams.start_threshold =
930                 config->period_count * config->period_size / 2;
931     } else
932         sparams.start_threshold = config->start_threshold;
933 
934     /* pick a high stop threshold - todo: does this need further tuning */
935     if (!config->stop_threshold) {
936         if (pcm->flags & PCM_IN)
937             pcm->config.stop_threshold = sparams.stop_threshold =
938                 config->period_count * config->period_size * 10;
939         else
940             pcm->config.stop_threshold = sparams.stop_threshold =
941                 config->period_count * config->period_size;
942     }
943     else
944         sparams.stop_threshold = config->stop_threshold;
945 
946     if (!pcm->config.avail_min) {
947         if (pcm->flags & PCM_MMAP)
948             pcm->config.avail_min = sparams.avail_min = pcm->config.period_size;
949         else
950             pcm->config.avail_min = sparams.avail_min = 1;
951     } else
952         sparams.avail_min = config->avail_min;
953 
954     sparams.xfer_align = config->period_size / 2; /* needed for old kernels */
955     sparams.silence_threshold = config->silence_threshold;
956     sparams.silence_size = config->silence_size;
957     pcm->boundary = sparams.boundary = pcm->buffer_size;
958 
959     while (pcm->boundary * 2 <= INT_MAX - pcm->buffer_size)
960         pcm->boundary *= 2;
961 
962     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SW_PARAMS, &sparams)) {
963         oops(pcm, errno, "cannot set sw params");
964         goto fail;
965     }
966 
967     rc = pcm_hw_mmap_status(pcm);
968     if (rc < 0) {
969         oops(pcm, rc, "mmap status failed");
970         goto fail;
971     }
972 
973 #ifdef SNDRV_PCM_IOCTL_TTSTAMP
974     if (pcm->flags & PCM_MONOTONIC) {
975         int arg = SNDRV_PCM_TSTAMP_TYPE_MONOTONIC;
976         rc = ioctl(pcm->fd, SNDRV_PCM_IOCTL_TTSTAMP, &arg);
977         if (rc < 0) {
978             oops(pcm, rc, "cannot set timestamp type");
979             goto fail;
980         }
981     }
982 #endif
983 
984     pcm->underruns = 0;
985     return pcm;
986 
987 fail:
988     if (flags & PCM_MMAP)
989         munmap(pcm->mmap_buffer, pcm_frames_to_bytes(pcm, pcm->buffer_size));
990 fail_close:
991     close(pcm->fd);
992     pcm->fd = -1;
993     return pcm;
994 }
995 
pcm_is_ready(struct pcm * pcm)996 int pcm_is_ready(struct pcm *pcm)
997 {
998     return pcm->fd >= 0;
999 }
1000 
pcm_prepare(struct pcm * pcm)1001 int pcm_prepare(struct pcm *pcm)
1002 {
1003     if (pcm->prepared)
1004         return 0;
1005 
1006     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_PREPARE) < 0)
1007         return oops(pcm, errno, "cannot prepare channel");
1008 
1009     pcm->prepared = 1;
1010     return 0;
1011 }
1012 
pcm_start(struct pcm * pcm)1013 int pcm_start(struct pcm *pcm)
1014 {
1015     int prepare_error = pcm_prepare(pcm);
1016     if (prepare_error)
1017         return prepare_error;
1018 
1019     if (pcm->flags & PCM_MMAP)
1020 	    pcm_sync_ptr(pcm, 0);
1021 
1022     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_START) < 0)
1023         return oops(pcm, errno, "cannot start channel");
1024 
1025     pcm->running = 1;
1026     return 0;
1027 }
1028 
pcm_stop(struct pcm * pcm)1029 int pcm_stop(struct pcm *pcm)
1030 {
1031     if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_DROP) < 0)
1032         return oops(pcm, errno, "cannot stop channel");
1033 
1034     pcm->prepared = 0;
1035     pcm->running = 0;
1036     return 0;
1037 }
1038 
pcm_mmap_playback_avail(struct pcm * pcm)1039 static inline int pcm_mmap_playback_avail(struct pcm *pcm)
1040 {
1041     int avail;
1042 
1043     avail = pcm->mmap_status->hw_ptr + pcm->buffer_size - pcm->mmap_control->appl_ptr;
1044 
1045     if (avail < 0)
1046         avail += pcm->boundary;
1047     else if (avail > (int)pcm->boundary)
1048         avail -= pcm->boundary;
1049 
1050     return avail;
1051 }
1052 
pcm_mmap_capture_avail(struct pcm * pcm)1053 static inline int pcm_mmap_capture_avail(struct pcm *pcm)
1054 {
1055     int avail = pcm->mmap_status->hw_ptr - pcm->mmap_control->appl_ptr;
1056     if (avail < 0)
1057         avail += pcm->boundary;
1058     return avail;
1059 }
1060 
pcm_mmap_avail(struct pcm * pcm)1061 int pcm_mmap_avail(struct pcm *pcm)
1062 {
1063     pcm_sync_ptr(pcm, SNDRV_PCM_SYNC_PTR_HWSYNC);
1064     if (pcm->flags & PCM_IN)
1065         return pcm_mmap_capture_avail(pcm);
1066     else
1067         return pcm_mmap_playback_avail(pcm);
1068 }
1069 
pcm_mmap_appl_forward(struct pcm * pcm,int frames)1070 static void pcm_mmap_appl_forward(struct pcm *pcm, int frames)
1071 {
1072     unsigned int appl_ptr = pcm->mmap_control->appl_ptr;
1073     appl_ptr += frames;
1074 
1075     /* check for boundary wrap */
1076     if (appl_ptr > pcm->boundary)
1077          appl_ptr -= pcm->boundary;
1078     pcm->mmap_control->appl_ptr = appl_ptr;
1079 }
1080 
pcm_mmap_begin(struct pcm * pcm,void ** areas,unsigned int * offset,unsigned int * frames)1081 int pcm_mmap_begin(struct pcm *pcm, void **areas, unsigned int *offset,
1082                    unsigned int *frames)
1083 {
1084     unsigned int continuous, copy_frames, avail;
1085 
1086     /* return the mmap buffer */
1087     *areas = pcm->mmap_buffer;
1088 
1089     /* and the application offset in frames */
1090     *offset = pcm->mmap_control->appl_ptr % pcm->buffer_size;
1091 
1092     avail = pcm_mmap_avail(pcm);
1093     if (avail > pcm->buffer_size)
1094         avail = pcm->buffer_size;
1095     continuous = pcm->buffer_size - *offset;
1096 
1097     /* we can only copy frames if the are availabale and continuos */
1098     copy_frames = *frames;
1099     if (copy_frames > avail)
1100         copy_frames = avail;
1101     if (copy_frames > continuous)
1102         copy_frames = continuous;
1103     *frames = copy_frames;
1104 
1105     return 0;
1106 }
1107 
pcm_mmap_commit(struct pcm * pcm,unsigned int offset,unsigned int frames)1108 int pcm_mmap_commit(struct pcm *pcm, unsigned int offset __attribute__((unused)), unsigned int frames)
1109 {
1110     /* update the application pointer in userspace and kernel */
1111     pcm_mmap_appl_forward(pcm, frames);
1112     pcm_sync_ptr(pcm, 0);
1113 
1114     return frames;
1115 }
1116 
pcm_avail_update(struct pcm * pcm)1117 int pcm_avail_update(struct pcm *pcm)
1118 {
1119     pcm_sync_ptr(pcm, 0);
1120     return pcm_mmap_avail(pcm);
1121 }
1122 
pcm_state(struct pcm * pcm)1123 int pcm_state(struct pcm *pcm)
1124 {
1125     int err = pcm_sync_ptr(pcm, 0);
1126     if (err < 0)
1127         return err;
1128 
1129     return pcm->mmap_status->state;
1130 }
1131 
pcm_set_avail_min(struct pcm * pcm,int avail_min)1132 int pcm_set_avail_min(struct pcm *pcm, int avail_min)
1133 {
1134     if ((~pcm->flags) & (PCM_MMAP | PCM_NOIRQ))
1135         return -ENOSYS;
1136 
1137     pcm->config.avail_min = avail_min;
1138     return 0;
1139 }
1140 
pcm_wait(struct pcm * pcm,int timeout)1141 int pcm_wait(struct pcm *pcm, int timeout)
1142 {
1143     struct pollfd pfd;
1144     int err;
1145 
1146     pfd.fd = pcm->fd;
1147     pfd.events = POLLOUT | POLLERR | POLLNVAL;
1148 
1149     do {
1150         /* let's wait for avail or timeout */
1151         err = poll(&pfd, 1, timeout);
1152         if (err < 0)
1153             return -errno;
1154 
1155         /* timeout ? */
1156         if (err == 0)
1157             return 0;
1158 
1159         /* have we been interrupted ? */
1160         if (errno == -EINTR)
1161             continue;
1162 
1163         /* check for any errors */
1164         if (pfd.revents & (POLLERR | POLLNVAL)) {
1165             switch (pcm_state(pcm)) {
1166             case PCM_STATE_XRUN:
1167                 return -EPIPE;
1168             case PCM_STATE_SUSPENDED:
1169                 return -ESTRPIPE;
1170             case PCM_STATE_DISCONNECTED:
1171                 return -ENODEV;
1172             default:
1173                 return -EIO;
1174             }
1175         }
1176     /* poll again if fd not ready for IO */
1177     } while (!(pfd.revents & (POLLIN | POLLOUT)));
1178 
1179     return 1;
1180 }
1181 
pcm_get_poll_fd(struct pcm * pcm)1182 int pcm_get_poll_fd(struct pcm *pcm)
1183 {
1184     return pcm->fd;
1185 }
1186 
pcm_mmap_transfer(struct pcm * pcm,const void * buffer,unsigned int bytes)1187 int pcm_mmap_transfer(struct pcm *pcm, const void *buffer, unsigned int bytes)
1188 {
1189     int err = 0, frames, avail;
1190     unsigned int offset = 0, count;
1191 
1192     if (bytes == 0)
1193         return 0;
1194 
1195     count = pcm_bytes_to_frames(pcm, bytes);
1196 
1197     while (count > 0) {
1198 
1199         /* get the available space for writing new frames */
1200         avail = pcm_avail_update(pcm);
1201         if (avail < 0) {
1202             fprintf(stderr, "cannot determine available mmap frames");
1203             return err;
1204         }
1205 
1206         /* start the audio if we reach the threshold */
1207 	    if (!pcm->running &&
1208             (pcm->buffer_size - avail) >= pcm->config.start_threshold) {
1209             if (pcm_start(pcm) < 0) {
1210                fprintf(stderr, "start error: hw 0x%x app 0x%x avail 0x%x\n",
1211                     (unsigned int)pcm->mmap_status->hw_ptr,
1212                     (unsigned int)pcm->mmap_control->appl_ptr,
1213                     avail);
1214                 return -errno;
1215             }
1216             pcm->wait_for_avail_min = 0;
1217         }
1218 
1219         /* sleep until we have space to write new frames */
1220         if (pcm->running) {
1221             /* enable waiting for avail_min threshold when less frames than we have to write
1222              * are available. */
1223             if (!pcm->wait_for_avail_min && (count > (unsigned int)avail))
1224                 pcm->wait_for_avail_min = 1;
1225 
1226             if (pcm->wait_for_avail_min && (avail < pcm->config.avail_min)) {
1227                 int time = -1;
1228 
1229                 /* disable waiting for avail_min threshold to allow small amounts of data to be
1230                  * written without waiting as long as there is enough room in buffer. */
1231                 pcm->wait_for_avail_min = 0;
1232 
1233                 if (pcm->flags & PCM_NOIRQ)
1234                     time = (pcm->config.avail_min - avail) / pcm->noirq_frames_per_msec;
1235 
1236                 err = pcm_wait(pcm, time);
1237                 if (err < 0) {
1238                     pcm->prepared = 0;
1239                     pcm->running = 0;
1240                     oops(pcm, err, "wait error: hw 0x%x app 0x%x avail 0x%x\n",
1241                         (unsigned int)pcm->mmap_status->hw_ptr,
1242                         (unsigned int)pcm->mmap_control->appl_ptr,
1243                         avail);
1244                     pcm->mmap_control->appl_ptr = 0;
1245                     return err;
1246                 }
1247                 continue;
1248             }
1249         }
1250 
1251         frames = count;
1252         if (frames > avail)
1253             frames = avail;
1254 
1255         if (!frames)
1256             break;
1257 
1258         /* copy frames from buffer */
1259         frames = pcm_mmap_transfer_areas(pcm, (void *)buffer, offset, frames);
1260         if (frames < 0) {
1261             fprintf(stderr, "write error: hw 0x%x app 0x%x avail 0x%x\n",
1262                     (unsigned int)pcm->mmap_status->hw_ptr,
1263                     (unsigned int)pcm->mmap_control->appl_ptr,
1264                     avail);
1265             return frames;
1266         }
1267 
1268         offset += frames;
1269         count -= frames;
1270     }
1271 
1272     return 0;
1273 }
1274 
pcm_mmap_write(struct pcm * pcm,const void * data,unsigned int count)1275 int pcm_mmap_write(struct pcm *pcm, const void *data, unsigned int count)
1276 {
1277     if ((~pcm->flags) & (PCM_OUT | PCM_MMAP))
1278         return -ENOSYS;
1279 
1280     return pcm_mmap_transfer(pcm, (void *)data, count);
1281 }
1282 
pcm_mmap_read(struct pcm * pcm,void * data,unsigned int count)1283 int pcm_mmap_read(struct pcm *pcm, void *data, unsigned int count)
1284 {
1285     if ((~pcm->flags) & (PCM_IN | PCM_MMAP))
1286         return -ENOSYS;
1287 
1288     return pcm_mmap_transfer(pcm, data, count);
1289 }
1290 
pcm_ioctl(struct pcm * pcm,int request,...)1291 int pcm_ioctl(struct pcm *pcm, int request, ...)
1292 {
1293     va_list ap;
1294     void * arg;
1295 
1296     if (!pcm_is_ready(pcm))
1297         return -1;
1298 
1299     va_start(ap, request);
1300     arg = va_arg(ap, void *);
1301     va_end(ap);
1302 
1303     return ioctl(pcm->fd, request, arg);
1304 }
1305