xref: /openbmc/qemu/audio/alsaaudio.c (revision 773495364ffbfc6a4d1e13e24e932f96409ba1d3)
1 /*
2  * QEMU ALSA audio driver
3  *
4  * Copyright (c) 2005 Vassili Karpov (malc)
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 #include <alsa/asoundlib.h>
25 #include "qemu-common.h"
26 #include "qemu/main-loop.h"
27 #include "audio.h"
28 
29 #if QEMU_GNUC_PREREQ(4, 3)
30 #pragma GCC diagnostic ignored "-Waddress"
31 #endif
32 
33 #define AUDIO_CAP "alsa"
34 #include "audio_int.h"
35 
36 struct pollhlp {
37     snd_pcm_t *handle;
38     struct pollfd *pfds;
39     int count;
40     int mask;
41 };
42 
43 typedef struct ALSAVoiceOut {
44     HWVoiceOut hw;
45     int wpos;
46     int pending;
47     void *pcm_buf;
48     snd_pcm_t *handle;
49     struct pollhlp pollhlp;
50 } ALSAVoiceOut;
51 
52 typedef struct ALSAVoiceIn {
53     HWVoiceIn hw;
54     snd_pcm_t *handle;
55     void *pcm_buf;
56     struct pollhlp pollhlp;
57 } ALSAVoiceIn;
58 
59 static struct {
60     int size_in_usec_in;
61     int size_in_usec_out;
62     const char *pcm_name_in;
63     const char *pcm_name_out;
64     unsigned int buffer_size_in;
65     unsigned int period_size_in;
66     unsigned int buffer_size_out;
67     unsigned int period_size_out;
68     unsigned int threshold;
69 
70     int buffer_size_in_overridden;
71     int period_size_in_overridden;
72 
73     int buffer_size_out_overridden;
74     int period_size_out_overridden;
75     int verbose;
76 } conf = {
77     .buffer_size_out = 4096,
78     .period_size_out = 1024,
79     .pcm_name_out = "default",
80     .pcm_name_in = "default",
81 };
82 
83 struct alsa_params_req {
84     int freq;
85     snd_pcm_format_t fmt;
86     int nchannels;
87     int size_in_usec;
88     int override_mask;
89     unsigned int buffer_size;
90     unsigned int period_size;
91 };
92 
93 struct alsa_params_obt {
94     int freq;
95     audfmt_e fmt;
96     int endianness;
97     int nchannels;
98     snd_pcm_uframes_t samples;
99 };
100 
101 static void GCC_FMT_ATTR (2, 3) alsa_logerr (int err, const char *fmt, ...)
102 {
103     va_list ap;
104 
105     va_start (ap, fmt);
106     AUD_vlog (AUDIO_CAP, fmt, ap);
107     va_end (ap);
108 
109     AUD_log (AUDIO_CAP, "Reason: %s\n", snd_strerror (err));
110 }
111 
112 static void GCC_FMT_ATTR (3, 4) alsa_logerr2 (
113     int err,
114     const char *typ,
115     const char *fmt,
116     ...
117     )
118 {
119     va_list ap;
120 
121     AUD_log (AUDIO_CAP, "Could not initialize %s\n", typ);
122 
123     va_start (ap, fmt);
124     AUD_vlog (AUDIO_CAP, fmt, ap);
125     va_end (ap);
126 
127     AUD_log (AUDIO_CAP, "Reason: %s\n", snd_strerror (err));
128 }
129 
130 static void alsa_fini_poll (struct pollhlp *hlp)
131 {
132     int i;
133     struct pollfd *pfds = hlp->pfds;
134 
135     if (pfds) {
136         for (i = 0; i < hlp->count; ++i) {
137             qemu_set_fd_handler (pfds[i].fd, NULL, NULL, NULL);
138         }
139         g_free (pfds);
140     }
141     hlp->pfds = NULL;
142     hlp->count = 0;
143     hlp->handle = NULL;
144 }
145 
146 static void alsa_anal_close1 (snd_pcm_t **handlep)
147 {
148     int err = snd_pcm_close (*handlep);
149     if (err) {
150         alsa_logerr (err, "Failed to close PCM handle %p\n", *handlep);
151     }
152     *handlep = NULL;
153 }
154 
155 static void alsa_anal_close (snd_pcm_t **handlep, struct pollhlp *hlp)
156 {
157     alsa_fini_poll (hlp);
158     alsa_anal_close1 (handlep);
159 }
160 
161 static int alsa_recover (snd_pcm_t *handle)
162 {
163     int err = snd_pcm_prepare (handle);
164     if (err < 0) {
165         alsa_logerr (err, "Failed to prepare handle %p\n", handle);
166         return -1;
167     }
168     return 0;
169 }
170 
171 static int alsa_resume (snd_pcm_t *handle)
172 {
173     int err = snd_pcm_resume (handle);
174     if (err < 0) {
175         alsa_logerr (err, "Failed to resume handle %p\n", handle);
176         return -1;
177     }
178     return 0;
179 }
180 
181 static void alsa_poll_handler (void *opaque)
182 {
183     int err, count;
184     snd_pcm_state_t state;
185     struct pollhlp *hlp = opaque;
186     unsigned short revents;
187 
188     count = poll (hlp->pfds, hlp->count, 0);
189     if (count < 0) {
190         dolog ("alsa_poll_handler: poll %s\n", strerror (errno));
191         return;
192     }
193 
194     if (!count) {
195         return;
196     }
197 
198     /* XXX: ALSA example uses initial count, not the one returned by
199        poll, correct? */
200     err = snd_pcm_poll_descriptors_revents (hlp->handle, hlp->pfds,
201                                             hlp->count, &revents);
202     if (err < 0) {
203         alsa_logerr (err, "snd_pcm_poll_descriptors_revents");
204         return;
205     }
206 
207     if (!(revents & hlp->mask)) {
208         if (conf.verbose) {
209             dolog ("revents = %d\n", revents);
210         }
211         return;
212     }
213 
214     state = snd_pcm_state (hlp->handle);
215     switch (state) {
216     case SND_PCM_STATE_SETUP:
217         alsa_recover (hlp->handle);
218         break;
219 
220     case SND_PCM_STATE_XRUN:
221         alsa_recover (hlp->handle);
222         break;
223 
224     case SND_PCM_STATE_SUSPENDED:
225         alsa_resume (hlp->handle);
226         break;
227 
228     case SND_PCM_STATE_PREPARED:
229         audio_run ("alsa run (prepared)");
230         break;
231 
232     case SND_PCM_STATE_RUNNING:
233         audio_run ("alsa run (running)");
234         break;
235 
236     default:
237         dolog ("Unexpected state %d\n", state);
238     }
239 }
240 
241 static int alsa_poll_helper (snd_pcm_t *handle, struct pollhlp *hlp, int mask)
242 {
243     int i, count, err;
244     struct pollfd *pfds;
245 
246     count = snd_pcm_poll_descriptors_count (handle);
247     if (count <= 0) {
248         dolog ("Could not initialize poll mode\n"
249                "Invalid number of poll descriptors %d\n", count);
250         return -1;
251     }
252 
253     pfds = audio_calloc ("alsa_poll_helper", count, sizeof (*pfds));
254     if (!pfds) {
255         dolog ("Could not initialize poll mode\n");
256         return -1;
257     }
258 
259     err = snd_pcm_poll_descriptors (handle, pfds, count);
260     if (err < 0) {
261         alsa_logerr (err, "Could not initialize poll mode\n"
262                      "Could not obtain poll descriptors\n");
263         g_free (pfds);
264         return -1;
265     }
266 
267     for (i = 0; i < count; ++i) {
268         if (pfds[i].events & POLLIN) {
269             qemu_set_fd_handler (pfds[i].fd, alsa_poll_handler, NULL, hlp);
270         }
271         if (pfds[i].events & POLLOUT) {
272             if (conf.verbose) {
273                 dolog ("POLLOUT %d %d\n", i, pfds[i].fd);
274             }
275             qemu_set_fd_handler (pfds[i].fd, NULL, alsa_poll_handler, hlp);
276         }
277         if (conf.verbose) {
278             dolog ("Set handler events=%#x index=%d fd=%d err=%d\n",
279                    pfds[i].events, i, pfds[i].fd, err);
280         }
281 
282     }
283     hlp->pfds = pfds;
284     hlp->count = count;
285     hlp->handle = handle;
286     hlp->mask = mask;
287     return 0;
288 }
289 
290 static int alsa_poll_out (HWVoiceOut *hw)
291 {
292     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
293 
294     return alsa_poll_helper (alsa->handle, &alsa->pollhlp, POLLOUT);
295 }
296 
297 static int alsa_poll_in (HWVoiceIn *hw)
298 {
299     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
300 
301     return alsa_poll_helper (alsa->handle, &alsa->pollhlp, POLLIN);
302 }
303 
304 static int alsa_write (SWVoiceOut *sw, void *buf, int len)
305 {
306     return audio_pcm_sw_write (sw, buf, len);
307 }
308 
309 static snd_pcm_format_t aud_to_alsafmt (audfmt_e fmt, int endianness)
310 {
311     switch (fmt) {
312     case AUD_FMT_S8:
313         return SND_PCM_FORMAT_S8;
314 
315     case AUD_FMT_U8:
316         return SND_PCM_FORMAT_U8;
317 
318     case AUD_FMT_S16:
319         if (endianness) {
320             return SND_PCM_FORMAT_S16_BE;
321         }
322         else {
323             return SND_PCM_FORMAT_S16_LE;
324         }
325 
326     case AUD_FMT_U16:
327         if (endianness) {
328             return SND_PCM_FORMAT_U16_BE;
329         }
330         else {
331             return SND_PCM_FORMAT_U16_LE;
332         }
333 
334     case AUD_FMT_S32:
335         if (endianness) {
336             return SND_PCM_FORMAT_S32_BE;
337         }
338         else {
339             return SND_PCM_FORMAT_S32_LE;
340         }
341 
342     case AUD_FMT_U32:
343         if (endianness) {
344             return SND_PCM_FORMAT_U32_BE;
345         }
346         else {
347             return SND_PCM_FORMAT_U32_LE;
348         }
349 
350     default:
351         dolog ("Internal logic error: Bad audio format %d\n", fmt);
352 #ifdef DEBUG_AUDIO
353         abort ();
354 #endif
355         return SND_PCM_FORMAT_U8;
356     }
357 }
358 
359 static int alsa_to_audfmt (snd_pcm_format_t alsafmt, audfmt_e *fmt,
360                            int *endianness)
361 {
362     switch (alsafmt) {
363     case SND_PCM_FORMAT_S8:
364         *endianness = 0;
365         *fmt = AUD_FMT_S8;
366         break;
367 
368     case SND_PCM_FORMAT_U8:
369         *endianness = 0;
370         *fmt = AUD_FMT_U8;
371         break;
372 
373     case SND_PCM_FORMAT_S16_LE:
374         *endianness = 0;
375         *fmt = AUD_FMT_S16;
376         break;
377 
378     case SND_PCM_FORMAT_U16_LE:
379         *endianness = 0;
380         *fmt = AUD_FMT_U16;
381         break;
382 
383     case SND_PCM_FORMAT_S16_BE:
384         *endianness = 1;
385         *fmt = AUD_FMT_S16;
386         break;
387 
388     case SND_PCM_FORMAT_U16_BE:
389         *endianness = 1;
390         *fmt = AUD_FMT_U16;
391         break;
392 
393     case SND_PCM_FORMAT_S32_LE:
394         *endianness = 0;
395         *fmt = AUD_FMT_S32;
396         break;
397 
398     case SND_PCM_FORMAT_U32_LE:
399         *endianness = 0;
400         *fmt = AUD_FMT_U32;
401         break;
402 
403     case SND_PCM_FORMAT_S32_BE:
404         *endianness = 1;
405         *fmt = AUD_FMT_S32;
406         break;
407 
408     case SND_PCM_FORMAT_U32_BE:
409         *endianness = 1;
410         *fmt = AUD_FMT_U32;
411         break;
412 
413     default:
414         dolog ("Unrecognized audio format %d\n", alsafmt);
415         return -1;
416     }
417 
418     return 0;
419 }
420 
421 static void alsa_dump_info (struct alsa_params_req *req,
422                             struct alsa_params_obt *obt,
423                             snd_pcm_format_t obtfmt)
424 {
425     dolog ("parameter | requested value | obtained value\n");
426     dolog ("format    |      %10d |     %10d\n", req->fmt, obtfmt);
427     dolog ("channels  |      %10d |     %10d\n",
428            req->nchannels, obt->nchannels);
429     dolog ("frequency |      %10d |     %10d\n", req->freq, obt->freq);
430     dolog ("============================================\n");
431     dolog ("requested: buffer size %d period size %d\n",
432            req->buffer_size, req->period_size);
433     dolog ("obtained: samples %ld\n", obt->samples);
434 }
435 
436 static void alsa_set_threshold (snd_pcm_t *handle, snd_pcm_uframes_t threshold)
437 {
438     int err;
439     snd_pcm_sw_params_t *sw_params;
440 
441     snd_pcm_sw_params_alloca (&sw_params);
442 
443     err = snd_pcm_sw_params_current (handle, sw_params);
444     if (err < 0) {
445         dolog ("Could not fully initialize DAC\n");
446         alsa_logerr (err, "Failed to get current software parameters\n");
447         return;
448     }
449 
450     err = snd_pcm_sw_params_set_start_threshold (handle, sw_params, threshold);
451     if (err < 0) {
452         dolog ("Could not fully initialize DAC\n");
453         alsa_logerr (err, "Failed to set software threshold to %ld\n",
454                      threshold);
455         return;
456     }
457 
458     err = snd_pcm_sw_params (handle, sw_params);
459     if (err < 0) {
460         dolog ("Could not fully initialize DAC\n");
461         alsa_logerr (err, "Failed to set software parameters\n");
462         return;
463     }
464 }
465 
466 static int alsa_open (int in, struct alsa_params_req *req,
467                       struct alsa_params_obt *obt, snd_pcm_t **handlep)
468 {
469     snd_pcm_t *handle;
470     snd_pcm_hw_params_t *hw_params;
471     int err;
472     int size_in_usec;
473     unsigned int freq, nchannels;
474     const char *pcm_name = in ? conf.pcm_name_in : conf.pcm_name_out;
475     snd_pcm_uframes_t obt_buffer_size;
476     const char *typ = in ? "ADC" : "DAC";
477     snd_pcm_format_t obtfmt;
478 
479     freq = req->freq;
480     nchannels = req->nchannels;
481     size_in_usec = req->size_in_usec;
482 
483     snd_pcm_hw_params_alloca (&hw_params);
484 
485     err = snd_pcm_open (
486         &handle,
487         pcm_name,
488         in ? SND_PCM_STREAM_CAPTURE : SND_PCM_STREAM_PLAYBACK,
489         SND_PCM_NONBLOCK
490         );
491     if (err < 0) {
492         alsa_logerr2 (err, typ, "Failed to open `%s':\n", pcm_name);
493         return -1;
494     }
495 
496     err = snd_pcm_hw_params_any (handle, hw_params);
497     if (err < 0) {
498         alsa_logerr2 (err, typ, "Failed to initialize hardware parameters\n");
499         goto err;
500     }
501 
502     err = snd_pcm_hw_params_set_access (
503         handle,
504         hw_params,
505         SND_PCM_ACCESS_RW_INTERLEAVED
506         );
507     if (err < 0) {
508         alsa_logerr2 (err, typ, "Failed to set access type\n");
509         goto err;
510     }
511 
512     err = snd_pcm_hw_params_set_format (handle, hw_params, req->fmt);
513     if (err < 0 && conf.verbose) {
514         alsa_logerr2 (err, typ, "Failed to set format %d\n", req->fmt);
515     }
516 
517     err = snd_pcm_hw_params_set_rate_near (handle, hw_params, &freq, 0);
518     if (err < 0) {
519         alsa_logerr2 (err, typ, "Failed to set frequency %d\n", req->freq);
520         goto err;
521     }
522 
523     err = snd_pcm_hw_params_set_channels_near (
524         handle,
525         hw_params,
526         &nchannels
527         );
528     if (err < 0) {
529         alsa_logerr2 (err, typ, "Failed to set number of channels %d\n",
530                       req->nchannels);
531         goto err;
532     }
533 
534     if (nchannels != 1 && nchannels != 2) {
535         alsa_logerr2 (err, typ,
536                       "Can not handle obtained number of channels %d\n",
537                       nchannels);
538         goto err;
539     }
540 
541     if (req->buffer_size) {
542         unsigned long obt;
543 
544         if (size_in_usec) {
545             int dir = 0;
546             unsigned int btime = req->buffer_size;
547 
548             err = snd_pcm_hw_params_set_buffer_time_near (
549                 handle,
550                 hw_params,
551                 &btime,
552                 &dir
553                 );
554             obt = btime;
555         }
556         else {
557             snd_pcm_uframes_t bsize = req->buffer_size;
558 
559             err = snd_pcm_hw_params_set_buffer_size_near (
560                 handle,
561                 hw_params,
562                 &bsize
563                 );
564             obt = bsize;
565         }
566         if (err < 0) {
567             alsa_logerr2 (err, typ, "Failed to set buffer %s to %d\n",
568                           size_in_usec ? "time" : "size", req->buffer_size);
569             goto err;
570         }
571 
572         if ((req->override_mask & 2) && (obt - req->buffer_size))
573             dolog ("Requested buffer %s %u was rejected, using %lu\n",
574                    size_in_usec ? "time" : "size", req->buffer_size, obt);
575     }
576 
577     if (req->period_size) {
578         unsigned long obt;
579 
580         if (size_in_usec) {
581             int dir = 0;
582             unsigned int ptime = req->period_size;
583 
584             err = snd_pcm_hw_params_set_period_time_near (
585                 handle,
586                 hw_params,
587                 &ptime,
588                 &dir
589                 );
590             obt = ptime;
591         }
592         else {
593             int dir = 0;
594             snd_pcm_uframes_t psize = req->period_size;
595 
596             err = snd_pcm_hw_params_set_period_size_near (
597                 handle,
598                 hw_params,
599                 &psize,
600                 &dir
601                 );
602             obt = psize;
603         }
604 
605         if (err < 0) {
606             alsa_logerr2 (err, typ, "Failed to set period %s to %d\n",
607                           size_in_usec ? "time" : "size", req->period_size);
608             goto err;
609         }
610 
611         if (((req->override_mask & 1) && (obt - req->period_size)))
612             dolog ("Requested period %s %u was rejected, using %lu\n",
613                    size_in_usec ? "time" : "size", req->period_size, obt);
614     }
615 
616     err = snd_pcm_hw_params (handle, hw_params);
617     if (err < 0) {
618         alsa_logerr2 (err, typ, "Failed to apply audio parameters\n");
619         goto err;
620     }
621 
622     err = snd_pcm_hw_params_get_buffer_size (hw_params, &obt_buffer_size);
623     if (err < 0) {
624         alsa_logerr2 (err, typ, "Failed to get buffer size\n");
625         goto err;
626     }
627 
628     err = snd_pcm_hw_params_get_format (hw_params, &obtfmt);
629     if (err < 0) {
630         alsa_logerr2 (err, typ, "Failed to get format\n");
631         goto err;
632     }
633 
634     if (alsa_to_audfmt (obtfmt, &obt->fmt, &obt->endianness)) {
635         dolog ("Invalid format was returned %d\n", obtfmt);
636         goto err;
637     }
638 
639     err = snd_pcm_prepare (handle);
640     if (err < 0) {
641         alsa_logerr2 (err, typ, "Could not prepare handle %p\n", handle);
642         goto err;
643     }
644 
645     if (!in && conf.threshold) {
646         snd_pcm_uframes_t threshold;
647         int bytes_per_sec;
648 
649         bytes_per_sec = freq << (nchannels == 2);
650 
651         switch (obt->fmt) {
652         case AUD_FMT_S8:
653         case AUD_FMT_U8:
654             break;
655 
656         case AUD_FMT_S16:
657         case AUD_FMT_U16:
658             bytes_per_sec <<= 1;
659             break;
660 
661         case AUD_FMT_S32:
662         case AUD_FMT_U32:
663             bytes_per_sec <<= 2;
664             break;
665         }
666 
667         threshold = (conf.threshold * bytes_per_sec) / 1000;
668         alsa_set_threshold (handle, threshold);
669     }
670 
671     obt->nchannels = nchannels;
672     obt->freq = freq;
673     obt->samples = obt_buffer_size;
674 
675     *handlep = handle;
676 
677     if (conf.verbose &&
678         (obtfmt != req->fmt ||
679          obt->nchannels != req->nchannels ||
680          obt->freq != req->freq)) {
681         dolog ("Audio parameters for %s\n", typ);
682         alsa_dump_info (req, obt, obtfmt);
683     }
684 
685 #ifdef DEBUG
686     alsa_dump_info (req, obt, obtfmt);
687 #endif
688     return 0;
689 
690  err:
691     alsa_anal_close1 (&handle);
692     return -1;
693 }
694 
695 static snd_pcm_sframes_t alsa_get_avail (snd_pcm_t *handle)
696 {
697     snd_pcm_sframes_t avail;
698 
699     avail = snd_pcm_avail_update (handle);
700     if (avail < 0) {
701         if (avail == -EPIPE) {
702             if (!alsa_recover (handle)) {
703                 avail = snd_pcm_avail_update (handle);
704             }
705         }
706 
707         if (avail < 0) {
708             alsa_logerr (avail,
709                          "Could not obtain number of available frames\n");
710             return -1;
711         }
712     }
713 
714     return avail;
715 }
716 
717 static void alsa_write_pending (ALSAVoiceOut *alsa)
718 {
719     HWVoiceOut *hw = &alsa->hw;
720 
721     while (alsa->pending) {
722         int left_till_end_samples = hw->samples - alsa->wpos;
723         int len = audio_MIN (alsa->pending, left_till_end_samples);
724         char *src = advance (alsa->pcm_buf, alsa->wpos << hw->info.shift);
725 
726         while (len) {
727             snd_pcm_sframes_t written;
728 
729             written = snd_pcm_writei (alsa->handle, src, len);
730 
731             if (written <= 0) {
732                 switch (written) {
733                 case 0:
734                     if (conf.verbose) {
735                         dolog ("Failed to write %d frames (wrote zero)\n", len);
736                     }
737                     return;
738 
739                 case -EPIPE:
740                     if (alsa_recover (alsa->handle)) {
741                         alsa_logerr (written, "Failed to write %d frames\n",
742                                      len);
743                         return;
744                     }
745                     if (conf.verbose) {
746                         dolog ("Recovering from playback xrun\n");
747                     }
748                     continue;
749 
750                 case -ESTRPIPE:
751                     /* stream is suspended and waiting for an
752                        application recovery */
753                     if (alsa_resume (alsa->handle)) {
754                         alsa_logerr (written, "Failed to write %d frames\n",
755                                      len);
756                         return;
757                     }
758                     if (conf.verbose) {
759                         dolog ("Resuming suspended output stream\n");
760                     }
761                     continue;
762 
763                 case -EAGAIN:
764                     return;
765 
766                 default:
767                     alsa_logerr (written, "Failed to write %d frames from %p\n",
768                                  len, src);
769                     return;
770                 }
771             }
772 
773             alsa->wpos = (alsa->wpos + written) % hw->samples;
774             alsa->pending -= written;
775             len -= written;
776         }
777     }
778 }
779 
780 static int alsa_run_out (HWVoiceOut *hw, int live)
781 {
782     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
783     int decr;
784     snd_pcm_sframes_t avail;
785 
786     avail = alsa_get_avail (alsa->handle);
787     if (avail < 0) {
788         dolog ("Could not get number of available playback frames\n");
789         return 0;
790     }
791 
792     decr = audio_MIN (live, avail);
793     decr = audio_pcm_hw_clip_out (hw, alsa->pcm_buf, decr, alsa->pending);
794     alsa->pending += decr;
795     alsa_write_pending (alsa);
796     return decr;
797 }
798 
799 static void alsa_fini_out (HWVoiceOut *hw)
800 {
801     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
802 
803     ldebug ("alsa_fini\n");
804     alsa_anal_close (&alsa->handle, &alsa->pollhlp);
805 
806     g_free(alsa->pcm_buf);
807     alsa->pcm_buf = NULL;
808 }
809 
810 static int alsa_init_out (HWVoiceOut *hw, struct audsettings *as)
811 {
812     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
813     struct alsa_params_req req;
814     struct alsa_params_obt obt;
815     snd_pcm_t *handle;
816     struct audsettings obt_as;
817 
818     req.fmt = aud_to_alsafmt (as->fmt, as->endianness);
819     req.freq = as->freq;
820     req.nchannels = as->nchannels;
821     req.period_size = conf.period_size_out;
822     req.buffer_size = conf.buffer_size_out;
823     req.size_in_usec = conf.size_in_usec_out;
824     req.override_mask =
825         (conf.period_size_out_overridden ? 1 : 0) |
826         (conf.buffer_size_out_overridden ? 2 : 0);
827 
828     if (alsa_open (0, &req, &obt, &handle)) {
829         return -1;
830     }
831 
832     obt_as.freq = obt.freq;
833     obt_as.nchannels = obt.nchannels;
834     obt_as.fmt = obt.fmt;
835     obt_as.endianness = obt.endianness;
836 
837     audio_pcm_init_info (&hw->info, &obt_as);
838     hw->samples = obt.samples;
839 
840     alsa->pcm_buf = audio_calloc (AUDIO_FUNC, obt.samples, 1 << hw->info.shift);
841     if (!alsa->pcm_buf) {
842         dolog ("Could not allocate DAC buffer (%d samples, each %d bytes)\n",
843                hw->samples, 1 << hw->info.shift);
844         alsa_anal_close1 (&handle);
845         return -1;
846     }
847 
848     alsa->handle = handle;
849     return 0;
850 }
851 
852 #define VOICE_CTL_PAUSE 0
853 #define VOICE_CTL_PREPARE 1
854 #define VOICE_CTL_START 2
855 
856 static int alsa_voice_ctl (snd_pcm_t *handle, const char *typ, int ctl)
857 {
858     int err;
859 
860     if (ctl == VOICE_CTL_PAUSE) {
861         err = snd_pcm_drop (handle);
862         if (err < 0) {
863             alsa_logerr (err, "Could not stop %s\n", typ);
864             return -1;
865         }
866     }
867     else {
868         err = snd_pcm_prepare (handle);
869         if (err < 0) {
870             alsa_logerr (err, "Could not prepare handle for %s\n", typ);
871             return -1;
872         }
873         if (ctl == VOICE_CTL_START) {
874             err = snd_pcm_start(handle);
875             if (err < 0) {
876                 alsa_logerr (err, "Could not start handle for %s\n", typ);
877                 return -1;
878             }
879         }
880     }
881 
882     return 0;
883 }
884 
885 static int alsa_ctl_out (HWVoiceOut *hw, int cmd, ...)
886 {
887     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
888 
889     switch (cmd) {
890     case VOICE_ENABLE:
891         {
892             va_list ap;
893             int poll_mode;
894 
895             va_start (ap, cmd);
896             poll_mode = va_arg (ap, int);
897             va_end (ap);
898 
899             ldebug ("enabling voice\n");
900             if (poll_mode && alsa_poll_out (hw)) {
901                 poll_mode = 0;
902             }
903             hw->poll_mode = poll_mode;
904             return alsa_voice_ctl (alsa->handle, "playback", VOICE_CTL_PREPARE);
905         }
906 
907     case VOICE_DISABLE:
908         ldebug ("disabling voice\n");
909         if (hw->poll_mode) {
910             hw->poll_mode = 0;
911             alsa_fini_poll (&alsa->pollhlp);
912         }
913         return alsa_voice_ctl (alsa->handle, "playback", VOICE_CTL_PAUSE);
914     }
915 
916     return -1;
917 }
918 
919 static int alsa_init_in (HWVoiceIn *hw, struct audsettings *as)
920 {
921     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
922     struct alsa_params_req req;
923     struct alsa_params_obt obt;
924     snd_pcm_t *handle;
925     struct audsettings obt_as;
926 
927     req.fmt = aud_to_alsafmt (as->fmt, as->endianness);
928     req.freq = as->freq;
929     req.nchannels = as->nchannels;
930     req.period_size = conf.period_size_in;
931     req.buffer_size = conf.buffer_size_in;
932     req.size_in_usec = conf.size_in_usec_in;
933     req.override_mask =
934         (conf.period_size_in_overridden ? 1 : 0) |
935         (conf.buffer_size_in_overridden ? 2 : 0);
936 
937     if (alsa_open (1, &req, &obt, &handle)) {
938         return -1;
939     }
940 
941     obt_as.freq = obt.freq;
942     obt_as.nchannels = obt.nchannels;
943     obt_as.fmt = obt.fmt;
944     obt_as.endianness = obt.endianness;
945 
946     audio_pcm_init_info (&hw->info, &obt_as);
947     hw->samples = obt.samples;
948 
949     alsa->pcm_buf = audio_calloc (AUDIO_FUNC, hw->samples, 1 << hw->info.shift);
950     if (!alsa->pcm_buf) {
951         dolog ("Could not allocate ADC buffer (%d samples, each %d bytes)\n",
952                hw->samples, 1 << hw->info.shift);
953         alsa_anal_close1 (&handle);
954         return -1;
955     }
956 
957     alsa->handle = handle;
958     return 0;
959 }
960 
961 static void alsa_fini_in (HWVoiceIn *hw)
962 {
963     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
964 
965     alsa_anal_close (&alsa->handle, &alsa->pollhlp);
966 
967     g_free(alsa->pcm_buf);
968     alsa->pcm_buf = NULL;
969 }
970 
971 static int alsa_run_in (HWVoiceIn *hw)
972 {
973     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
974     int hwshift = hw->info.shift;
975     int i;
976     int live = audio_pcm_hw_get_live_in (hw);
977     int dead = hw->samples - live;
978     int decr;
979     struct {
980         int add;
981         int len;
982     } bufs[2] = {
983         { .add = hw->wpos, .len = 0 },
984         { .add = 0,        .len = 0 }
985     };
986     snd_pcm_sframes_t avail;
987     snd_pcm_uframes_t read_samples = 0;
988 
989     if (!dead) {
990         return 0;
991     }
992 
993     avail = alsa_get_avail (alsa->handle);
994     if (avail < 0) {
995         dolog ("Could not get number of captured frames\n");
996         return 0;
997     }
998 
999     if (!avail) {
1000         snd_pcm_state_t state;
1001 
1002         state = snd_pcm_state (alsa->handle);
1003         switch (state) {
1004         case SND_PCM_STATE_PREPARED:
1005             avail = hw->samples;
1006             break;
1007         case SND_PCM_STATE_SUSPENDED:
1008             /* stream is suspended and waiting for an application recovery */
1009             if (alsa_resume (alsa->handle)) {
1010                 dolog ("Failed to resume suspended input stream\n");
1011                 return 0;
1012             }
1013             if (conf.verbose) {
1014                 dolog ("Resuming suspended input stream\n");
1015             }
1016             break;
1017         default:
1018             if (conf.verbose) {
1019                 dolog ("No frames available and ALSA state is %d\n", state);
1020             }
1021             return 0;
1022         }
1023     }
1024 
1025     decr = audio_MIN (dead, avail);
1026     if (!decr) {
1027         return 0;
1028     }
1029 
1030     if (hw->wpos + decr > hw->samples) {
1031         bufs[0].len = (hw->samples - hw->wpos);
1032         bufs[1].len = (decr - (hw->samples - hw->wpos));
1033     }
1034     else {
1035         bufs[0].len = decr;
1036     }
1037 
1038     for (i = 0; i < 2; ++i) {
1039         void *src;
1040         struct st_sample *dst;
1041         snd_pcm_sframes_t nread;
1042         snd_pcm_uframes_t len;
1043 
1044         len = bufs[i].len;
1045 
1046         src = advance (alsa->pcm_buf, bufs[i].add << hwshift);
1047         dst = hw->conv_buf + bufs[i].add;
1048 
1049         while (len) {
1050             nread = snd_pcm_readi (alsa->handle, src, len);
1051 
1052             if (nread <= 0) {
1053                 switch (nread) {
1054                 case 0:
1055                     if (conf.verbose) {
1056                         dolog ("Failed to read %ld frames (read zero)\n", len);
1057                     }
1058                     goto exit;
1059 
1060                 case -EPIPE:
1061                     if (alsa_recover (alsa->handle)) {
1062                         alsa_logerr (nread, "Failed to read %ld frames\n", len);
1063                         goto exit;
1064                     }
1065                     if (conf.verbose) {
1066                         dolog ("Recovering from capture xrun\n");
1067                     }
1068                     continue;
1069 
1070                 case -EAGAIN:
1071                     goto exit;
1072 
1073                 default:
1074                     alsa_logerr (
1075                         nread,
1076                         "Failed to read %ld frames from %p\n",
1077                         len,
1078                         src
1079                         );
1080                     goto exit;
1081                 }
1082             }
1083 
1084             hw->conv (dst, src, nread);
1085 
1086             src = advance (src, nread << hwshift);
1087             dst += nread;
1088 
1089             read_samples += nread;
1090             len -= nread;
1091         }
1092     }
1093 
1094  exit:
1095     hw->wpos = (hw->wpos + read_samples) % hw->samples;
1096     return read_samples;
1097 }
1098 
1099 static int alsa_read (SWVoiceIn *sw, void *buf, int size)
1100 {
1101     return audio_pcm_sw_read (sw, buf, size);
1102 }
1103 
1104 static int alsa_ctl_in (HWVoiceIn *hw, int cmd, ...)
1105 {
1106     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
1107 
1108     switch (cmd) {
1109     case VOICE_ENABLE:
1110         {
1111             va_list ap;
1112             int poll_mode;
1113 
1114             va_start (ap, cmd);
1115             poll_mode = va_arg (ap, int);
1116             va_end (ap);
1117 
1118             ldebug ("enabling voice\n");
1119             if (poll_mode && alsa_poll_in (hw)) {
1120                 poll_mode = 0;
1121             }
1122             hw->poll_mode = poll_mode;
1123 
1124             return alsa_voice_ctl (alsa->handle, "capture", VOICE_CTL_START);
1125         }
1126 
1127     case VOICE_DISABLE:
1128         ldebug ("disabling voice\n");
1129         if (hw->poll_mode) {
1130             hw->poll_mode = 0;
1131             alsa_fini_poll (&alsa->pollhlp);
1132         }
1133         return alsa_voice_ctl (alsa->handle, "capture", VOICE_CTL_PAUSE);
1134     }
1135 
1136     return -1;
1137 }
1138 
1139 static void *alsa_audio_init (void)
1140 {
1141     return &conf;
1142 }
1143 
1144 static void alsa_audio_fini (void *opaque)
1145 {
1146     (void) opaque;
1147 }
1148 
1149 static struct audio_option alsa_options[] = {
1150     {
1151         .name        = "DAC_SIZE_IN_USEC",
1152         .tag         = AUD_OPT_BOOL,
1153         .valp        = &conf.size_in_usec_out,
1154         .descr       = "DAC period/buffer size in microseconds (otherwise in frames)"
1155     },
1156     {
1157         .name        = "DAC_PERIOD_SIZE",
1158         .tag         = AUD_OPT_INT,
1159         .valp        = &conf.period_size_out,
1160         .descr       = "DAC period size (0 to go with system default)",
1161         .overriddenp = &conf.period_size_out_overridden
1162     },
1163     {
1164         .name        = "DAC_BUFFER_SIZE",
1165         .tag         = AUD_OPT_INT,
1166         .valp        = &conf.buffer_size_out,
1167         .descr       = "DAC buffer size (0 to go with system default)",
1168         .overriddenp = &conf.buffer_size_out_overridden
1169     },
1170     {
1171         .name        = "ADC_SIZE_IN_USEC",
1172         .tag         = AUD_OPT_BOOL,
1173         .valp        = &conf.size_in_usec_in,
1174         .descr       =
1175         "ADC period/buffer size in microseconds (otherwise in frames)"
1176     },
1177     {
1178         .name        = "ADC_PERIOD_SIZE",
1179         .tag         = AUD_OPT_INT,
1180         .valp        = &conf.period_size_in,
1181         .descr       = "ADC period size (0 to go with system default)",
1182         .overriddenp = &conf.period_size_in_overridden
1183     },
1184     {
1185         .name        = "ADC_BUFFER_SIZE",
1186         .tag         = AUD_OPT_INT,
1187         .valp        = &conf.buffer_size_in,
1188         .descr       = "ADC buffer size (0 to go with system default)",
1189         .overriddenp = &conf.buffer_size_in_overridden
1190     },
1191     {
1192         .name        = "THRESHOLD",
1193         .tag         = AUD_OPT_INT,
1194         .valp        = &conf.threshold,
1195         .descr       = "(undocumented)"
1196     },
1197     {
1198         .name        = "DAC_DEV",
1199         .tag         = AUD_OPT_STR,
1200         .valp        = &conf.pcm_name_out,
1201         .descr       = "DAC device name (for instance dmix)"
1202     },
1203     {
1204         .name        = "ADC_DEV",
1205         .tag         = AUD_OPT_STR,
1206         .valp        = &conf.pcm_name_in,
1207         .descr       = "ADC device name"
1208     },
1209     {
1210         .name        = "VERBOSE",
1211         .tag         = AUD_OPT_BOOL,
1212         .valp        = &conf.verbose,
1213         .descr       = "Behave in a more verbose way"
1214     },
1215     { /* End of list */ }
1216 };
1217 
1218 static struct audio_pcm_ops alsa_pcm_ops = {
1219     .init_out = alsa_init_out,
1220     .fini_out = alsa_fini_out,
1221     .run_out  = alsa_run_out,
1222     .write    = alsa_write,
1223     .ctl_out  = alsa_ctl_out,
1224 
1225     .init_in  = alsa_init_in,
1226     .fini_in  = alsa_fini_in,
1227     .run_in   = alsa_run_in,
1228     .read     = alsa_read,
1229     .ctl_in   = alsa_ctl_in,
1230 };
1231 
1232 struct audio_driver alsa_audio_driver = {
1233     .name           = "alsa",
1234     .descr          = "ALSA http://www.alsa-project.org",
1235     .options        = alsa_options,
1236     .init           = alsa_audio_init,
1237     .fini           = alsa_audio_fini,
1238     .pcm_ops        = &alsa_pcm_ops,
1239     .can_be_default = 1,
1240     .max_voices_out = INT_MAX,
1241     .max_voices_in  = INT_MAX,
1242     .voice_size_out = sizeof (ALSAVoiceOut),
1243     .voice_size_in  = sizeof (ALSAVoiceIn)
1244 };
1245