xref: /openbmc/qemu/audio/alsaaudio.c (revision 500eb6db)
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 
25 #include "qemu/osdep.h"
26 #include <alsa/asoundlib.h>
27 #include "qemu/main-loop.h"
28 #include "qemu/module.h"
29 #include "audio.h"
30 #include "trace.h"
31 
32 #pragma GCC diagnostic ignored "-Waddress"
33 
34 #define AUDIO_CAP "alsa"
35 #include "audio_int.h"
36 
37 struct pollhlp {
38     snd_pcm_t *handle;
39     struct pollfd *pfds;
40     int count;
41     int mask;
42 };
43 
44 typedef struct ALSAVoiceOut {
45     HWVoiceOut hw;
46     int wpos;
47     int pending;
48     void *pcm_buf;
49     snd_pcm_t *handle;
50     struct pollhlp pollhlp;
51     Audiodev *dev;
52 } ALSAVoiceOut;
53 
54 typedef struct ALSAVoiceIn {
55     HWVoiceIn hw;
56     snd_pcm_t *handle;
57     void *pcm_buf;
58     struct pollhlp pollhlp;
59     Audiodev *dev;
60 } ALSAVoiceIn;
61 
62 struct alsa_params_req {
63     int freq;
64     snd_pcm_format_t fmt;
65     int nchannels;
66 };
67 
68 struct alsa_params_obt {
69     int freq;
70     AudioFormat fmt;
71     int endianness;
72     int nchannels;
73     snd_pcm_uframes_t samples;
74 };
75 
76 static void GCC_FMT_ATTR (2, 3) alsa_logerr (int err, const char *fmt, ...)
77 {
78     va_list ap;
79 
80     va_start (ap, fmt);
81     AUD_vlog (AUDIO_CAP, fmt, ap);
82     va_end (ap);
83 
84     AUD_log (AUDIO_CAP, "Reason: %s\n", snd_strerror (err));
85 }
86 
87 static void GCC_FMT_ATTR (3, 4) alsa_logerr2 (
88     int err,
89     const char *typ,
90     const char *fmt,
91     ...
92     )
93 {
94     va_list ap;
95 
96     AUD_log (AUDIO_CAP, "Could not initialize %s\n", typ);
97 
98     va_start (ap, fmt);
99     AUD_vlog (AUDIO_CAP, fmt, ap);
100     va_end (ap);
101 
102     AUD_log (AUDIO_CAP, "Reason: %s\n", snd_strerror (err));
103 }
104 
105 static void alsa_fini_poll (struct pollhlp *hlp)
106 {
107     int i;
108     struct pollfd *pfds = hlp->pfds;
109 
110     if (pfds) {
111         for (i = 0; i < hlp->count; ++i) {
112             qemu_set_fd_handler (pfds[i].fd, NULL, NULL, NULL);
113         }
114         g_free (pfds);
115     }
116     hlp->pfds = NULL;
117     hlp->count = 0;
118     hlp->handle = NULL;
119 }
120 
121 static void alsa_anal_close1 (snd_pcm_t **handlep)
122 {
123     int err = snd_pcm_close (*handlep);
124     if (err) {
125         alsa_logerr (err, "Failed to close PCM handle %p\n", *handlep);
126     }
127     *handlep = NULL;
128 }
129 
130 static void alsa_anal_close (snd_pcm_t **handlep, struct pollhlp *hlp)
131 {
132     alsa_fini_poll (hlp);
133     alsa_anal_close1 (handlep);
134 }
135 
136 static int alsa_recover (snd_pcm_t *handle)
137 {
138     int err = snd_pcm_prepare (handle);
139     if (err < 0) {
140         alsa_logerr (err, "Failed to prepare handle %p\n", handle);
141         return -1;
142     }
143     return 0;
144 }
145 
146 static int alsa_resume (snd_pcm_t *handle)
147 {
148     int err = snd_pcm_resume (handle);
149     if (err < 0) {
150         alsa_logerr (err, "Failed to resume handle %p\n", handle);
151         return -1;
152     }
153     return 0;
154 }
155 
156 static void alsa_poll_handler (void *opaque)
157 {
158     int err, count;
159     snd_pcm_state_t state;
160     struct pollhlp *hlp = opaque;
161     unsigned short revents;
162 
163     count = poll (hlp->pfds, hlp->count, 0);
164     if (count < 0) {
165         dolog ("alsa_poll_handler: poll %s\n", strerror (errno));
166         return;
167     }
168 
169     if (!count) {
170         return;
171     }
172 
173     /* XXX: ALSA example uses initial count, not the one returned by
174        poll, correct? */
175     err = snd_pcm_poll_descriptors_revents (hlp->handle, hlp->pfds,
176                                             hlp->count, &revents);
177     if (err < 0) {
178         alsa_logerr (err, "snd_pcm_poll_descriptors_revents");
179         return;
180     }
181 
182     if (!(revents & hlp->mask)) {
183         trace_alsa_revents(revents);
184         return;
185     }
186 
187     state = snd_pcm_state (hlp->handle);
188     switch (state) {
189     case SND_PCM_STATE_SETUP:
190         alsa_recover (hlp->handle);
191         break;
192 
193     case SND_PCM_STATE_XRUN:
194         alsa_recover (hlp->handle);
195         break;
196 
197     case SND_PCM_STATE_SUSPENDED:
198         alsa_resume (hlp->handle);
199         break;
200 
201     case SND_PCM_STATE_PREPARED:
202         audio_run ("alsa run (prepared)");
203         break;
204 
205     case SND_PCM_STATE_RUNNING:
206         audio_run ("alsa run (running)");
207         break;
208 
209     default:
210         dolog ("Unexpected state %d\n", state);
211     }
212 }
213 
214 static int alsa_poll_helper (snd_pcm_t *handle, struct pollhlp *hlp, int mask)
215 {
216     int i, count, err;
217     struct pollfd *pfds;
218 
219     count = snd_pcm_poll_descriptors_count (handle);
220     if (count <= 0) {
221         dolog ("Could not initialize poll mode\n"
222                "Invalid number of poll descriptors %d\n", count);
223         return -1;
224     }
225 
226     pfds = audio_calloc ("alsa_poll_helper", count, sizeof (*pfds));
227     if (!pfds) {
228         dolog ("Could not initialize poll mode\n");
229         return -1;
230     }
231 
232     err = snd_pcm_poll_descriptors (handle, pfds, count);
233     if (err < 0) {
234         alsa_logerr (err, "Could not initialize poll mode\n"
235                      "Could not obtain poll descriptors\n");
236         g_free (pfds);
237         return -1;
238     }
239 
240     for (i = 0; i < count; ++i) {
241         if (pfds[i].events & POLLIN) {
242             qemu_set_fd_handler (pfds[i].fd, alsa_poll_handler, NULL, hlp);
243         }
244         if (pfds[i].events & POLLOUT) {
245             trace_alsa_pollout(i, pfds[i].fd);
246             qemu_set_fd_handler (pfds[i].fd, NULL, alsa_poll_handler, hlp);
247         }
248         trace_alsa_set_handler(pfds[i].events, i, pfds[i].fd, err);
249 
250     }
251     hlp->pfds = pfds;
252     hlp->count = count;
253     hlp->handle = handle;
254     hlp->mask = mask;
255     return 0;
256 }
257 
258 static int alsa_poll_out (HWVoiceOut *hw)
259 {
260     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
261 
262     return alsa_poll_helper (alsa->handle, &alsa->pollhlp, POLLOUT);
263 }
264 
265 static int alsa_poll_in (HWVoiceIn *hw)
266 {
267     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
268 
269     return alsa_poll_helper (alsa->handle, &alsa->pollhlp, POLLIN);
270 }
271 
272 static int alsa_write (SWVoiceOut *sw, void *buf, int len)
273 {
274     return audio_pcm_sw_write (sw, buf, len);
275 }
276 
277 static snd_pcm_format_t aud_to_alsafmt (AudioFormat fmt, int endianness)
278 {
279     switch (fmt) {
280     case AUDIO_FORMAT_S8:
281         return SND_PCM_FORMAT_S8;
282 
283     case AUDIO_FORMAT_U8:
284         return SND_PCM_FORMAT_U8;
285 
286     case AUDIO_FORMAT_S16:
287         if (endianness) {
288             return SND_PCM_FORMAT_S16_BE;
289         }
290         else {
291             return SND_PCM_FORMAT_S16_LE;
292         }
293 
294     case AUDIO_FORMAT_U16:
295         if (endianness) {
296             return SND_PCM_FORMAT_U16_BE;
297         }
298         else {
299             return SND_PCM_FORMAT_U16_LE;
300         }
301 
302     case AUDIO_FORMAT_S32:
303         if (endianness) {
304             return SND_PCM_FORMAT_S32_BE;
305         }
306         else {
307             return SND_PCM_FORMAT_S32_LE;
308         }
309 
310     case AUDIO_FORMAT_U32:
311         if (endianness) {
312             return SND_PCM_FORMAT_U32_BE;
313         }
314         else {
315             return SND_PCM_FORMAT_U32_LE;
316         }
317 
318     default:
319         dolog ("Internal logic error: Bad audio format %d\n", fmt);
320 #ifdef DEBUG_AUDIO
321         abort ();
322 #endif
323         return SND_PCM_FORMAT_U8;
324     }
325 }
326 
327 static int alsa_to_audfmt (snd_pcm_format_t alsafmt, AudioFormat *fmt,
328                            int *endianness)
329 {
330     switch (alsafmt) {
331     case SND_PCM_FORMAT_S8:
332         *endianness = 0;
333         *fmt = AUDIO_FORMAT_S8;
334         break;
335 
336     case SND_PCM_FORMAT_U8:
337         *endianness = 0;
338         *fmt = AUDIO_FORMAT_U8;
339         break;
340 
341     case SND_PCM_FORMAT_S16_LE:
342         *endianness = 0;
343         *fmt = AUDIO_FORMAT_S16;
344         break;
345 
346     case SND_PCM_FORMAT_U16_LE:
347         *endianness = 0;
348         *fmt = AUDIO_FORMAT_U16;
349         break;
350 
351     case SND_PCM_FORMAT_S16_BE:
352         *endianness = 1;
353         *fmt = AUDIO_FORMAT_S16;
354         break;
355 
356     case SND_PCM_FORMAT_U16_BE:
357         *endianness = 1;
358         *fmt = AUDIO_FORMAT_U16;
359         break;
360 
361     case SND_PCM_FORMAT_S32_LE:
362         *endianness = 0;
363         *fmt = AUDIO_FORMAT_S32;
364         break;
365 
366     case SND_PCM_FORMAT_U32_LE:
367         *endianness = 0;
368         *fmt = AUDIO_FORMAT_U32;
369         break;
370 
371     case SND_PCM_FORMAT_S32_BE:
372         *endianness = 1;
373         *fmt = AUDIO_FORMAT_S32;
374         break;
375 
376     case SND_PCM_FORMAT_U32_BE:
377         *endianness = 1;
378         *fmt = AUDIO_FORMAT_U32;
379         break;
380 
381     default:
382         dolog ("Unrecognized audio format %d\n", alsafmt);
383         return -1;
384     }
385 
386     return 0;
387 }
388 
389 static void alsa_dump_info (struct alsa_params_req *req,
390                             struct alsa_params_obt *obt,
391                             snd_pcm_format_t obtfmt,
392                             AudiodevAlsaPerDirectionOptions *apdo)
393 {
394     dolog("parameter | requested value | obtained value\n");
395     dolog("format    |      %10d |     %10d\n", req->fmt, obtfmt);
396     dolog("channels  |      %10d |     %10d\n",
397           req->nchannels, obt->nchannels);
398     dolog("frequency |      %10d |     %10d\n", req->freq, obt->freq);
399     dolog("============================================\n");
400     dolog("requested: buffer len %" PRId32 " period len %" PRId32 "\n",
401           apdo->buffer_length, apdo->period_length);
402     dolog("obtained: samples %ld\n", obt->samples);
403 }
404 
405 static void alsa_set_threshold (snd_pcm_t *handle, snd_pcm_uframes_t threshold)
406 {
407     int err;
408     snd_pcm_sw_params_t *sw_params;
409 
410     snd_pcm_sw_params_alloca (&sw_params);
411 
412     err = snd_pcm_sw_params_current (handle, sw_params);
413     if (err < 0) {
414         dolog ("Could not fully initialize DAC\n");
415         alsa_logerr (err, "Failed to get current software parameters\n");
416         return;
417     }
418 
419     err = snd_pcm_sw_params_set_start_threshold (handle, sw_params, threshold);
420     if (err < 0) {
421         dolog ("Could not fully initialize DAC\n");
422         alsa_logerr (err, "Failed to set software threshold to %ld\n",
423                      threshold);
424         return;
425     }
426 
427     err = snd_pcm_sw_params (handle, sw_params);
428     if (err < 0) {
429         dolog ("Could not fully initialize DAC\n");
430         alsa_logerr (err, "Failed to set software parameters\n");
431         return;
432     }
433 }
434 
435 static int alsa_open(bool in, struct alsa_params_req *req,
436                      struct alsa_params_obt *obt, snd_pcm_t **handlep,
437                      Audiodev *dev)
438 {
439     AudiodevAlsaOptions *aopts = &dev->u.alsa;
440     AudiodevAlsaPerDirectionOptions *apdo = in ? aopts->in : aopts->out;
441     snd_pcm_t *handle;
442     snd_pcm_hw_params_t *hw_params;
443     int err;
444     unsigned int freq, nchannels;
445     const char *pcm_name = apdo->has_dev ? apdo->dev : "default";
446     snd_pcm_uframes_t obt_buffer_size;
447     const char *typ = in ? "ADC" : "DAC";
448     snd_pcm_format_t obtfmt;
449 
450     freq = req->freq;
451     nchannels = req->nchannels;
452 
453     snd_pcm_hw_params_alloca (&hw_params);
454 
455     err = snd_pcm_open (
456         &handle,
457         pcm_name,
458         in ? SND_PCM_STREAM_CAPTURE : SND_PCM_STREAM_PLAYBACK,
459         SND_PCM_NONBLOCK
460         );
461     if (err < 0) {
462         alsa_logerr2 (err, typ, "Failed to open `%s':\n", pcm_name);
463         return -1;
464     }
465 
466     err = snd_pcm_hw_params_any (handle, hw_params);
467     if (err < 0) {
468         alsa_logerr2 (err, typ, "Failed to initialize hardware parameters\n");
469         goto err;
470     }
471 
472     err = snd_pcm_hw_params_set_access (
473         handle,
474         hw_params,
475         SND_PCM_ACCESS_RW_INTERLEAVED
476         );
477     if (err < 0) {
478         alsa_logerr2 (err, typ, "Failed to set access type\n");
479         goto err;
480     }
481 
482     err = snd_pcm_hw_params_set_format (handle, hw_params, req->fmt);
483     if (err < 0) {
484         alsa_logerr2 (err, typ, "Failed to set format %d\n", req->fmt);
485     }
486 
487     err = snd_pcm_hw_params_set_rate_near (handle, hw_params, &freq, 0);
488     if (err < 0) {
489         alsa_logerr2 (err, typ, "Failed to set frequency %d\n", req->freq);
490         goto err;
491     }
492 
493     err = snd_pcm_hw_params_set_channels_near (
494         handle,
495         hw_params,
496         &nchannels
497         );
498     if (err < 0) {
499         alsa_logerr2 (err, typ, "Failed to set number of channels %d\n",
500                       req->nchannels);
501         goto err;
502     }
503 
504     if (nchannels != 1 && nchannels != 2) {
505         alsa_logerr2 (err, typ,
506                       "Can not handle obtained number of channels %d\n",
507                       nchannels);
508         goto err;
509     }
510 
511     if (apdo->buffer_length) {
512         int dir = 0;
513         unsigned int btime = apdo->buffer_length;
514 
515         err = snd_pcm_hw_params_set_buffer_time_near(
516             handle, hw_params, &btime, &dir);
517 
518         if (err < 0) {
519             alsa_logerr2(err, typ, "Failed to set buffer time to %" PRId32 "\n",
520                          apdo->buffer_length);
521             goto err;
522         }
523 
524         if (apdo->has_buffer_length && btime != apdo->buffer_length) {
525             dolog("Requested buffer time %" PRId32
526                   " was rejected, using %u\n", apdo->buffer_length, btime);
527         }
528     }
529 
530     if (apdo->period_length) {
531         int dir = 0;
532         unsigned int ptime = apdo->period_length;
533 
534         err = snd_pcm_hw_params_set_period_time_near(handle, hw_params, &ptime,
535                                                      &dir);
536 
537         if (err < 0) {
538             alsa_logerr2(err, typ, "Failed to set period time to %" PRId32 "\n",
539                          apdo->period_length);
540             goto err;
541         }
542 
543         if (apdo->has_period_length && ptime != apdo->period_length) {
544             dolog("Requested period time %" PRId32 " was rejected, using %d\n",
545                   apdo->period_length, ptime);
546         }
547     }
548 
549     err = snd_pcm_hw_params (handle, hw_params);
550     if (err < 0) {
551         alsa_logerr2 (err, typ, "Failed to apply audio parameters\n");
552         goto err;
553     }
554 
555     err = snd_pcm_hw_params_get_buffer_size (hw_params, &obt_buffer_size);
556     if (err < 0) {
557         alsa_logerr2 (err, typ, "Failed to get buffer size\n");
558         goto err;
559     }
560 
561     err = snd_pcm_hw_params_get_format (hw_params, &obtfmt);
562     if (err < 0) {
563         alsa_logerr2 (err, typ, "Failed to get format\n");
564         goto err;
565     }
566 
567     if (alsa_to_audfmt (obtfmt, &obt->fmt, &obt->endianness)) {
568         dolog ("Invalid format was returned %d\n", obtfmt);
569         goto err;
570     }
571 
572     err = snd_pcm_prepare (handle);
573     if (err < 0) {
574         alsa_logerr2 (err, typ, "Could not prepare handle %p\n", handle);
575         goto err;
576     }
577 
578     if (!in && aopts->has_threshold && aopts->threshold) {
579         struct audsettings as = { .freq = freq };
580         alsa_set_threshold(
581             handle,
582             audio_buffer_frames(qapi_AudiodevAlsaPerDirectionOptions_base(apdo),
583                                 &as, aopts->threshold));
584     }
585 
586     obt->nchannels = nchannels;
587     obt->freq = freq;
588     obt->samples = obt_buffer_size;
589 
590     *handlep = handle;
591 
592     if (obtfmt != req->fmt ||
593          obt->nchannels != req->nchannels ||
594          obt->freq != req->freq) {
595         dolog ("Audio parameters for %s\n", typ);
596         alsa_dump_info(req, obt, obtfmt, apdo);
597     }
598 
599 #ifdef DEBUG
600     alsa_dump_info(req, obt, obtfmt, pdo);
601 #endif
602     return 0;
603 
604  err:
605     alsa_anal_close1 (&handle);
606     return -1;
607 }
608 
609 static snd_pcm_sframes_t alsa_get_avail (snd_pcm_t *handle)
610 {
611     snd_pcm_sframes_t avail;
612 
613     avail = snd_pcm_avail_update (handle);
614     if (avail < 0) {
615         if (avail == -EPIPE) {
616             if (!alsa_recover (handle)) {
617                 avail = snd_pcm_avail_update (handle);
618             }
619         }
620 
621         if (avail < 0) {
622             alsa_logerr (avail,
623                          "Could not obtain number of available frames\n");
624             return -1;
625         }
626     }
627 
628     return avail;
629 }
630 
631 static void alsa_write_pending (ALSAVoiceOut *alsa)
632 {
633     HWVoiceOut *hw = &alsa->hw;
634 
635     while (alsa->pending) {
636         int left_till_end_samples = hw->samples - alsa->wpos;
637         int len = audio_MIN (alsa->pending, left_till_end_samples);
638         char *src = advance (alsa->pcm_buf, alsa->wpos << hw->info.shift);
639 
640         while (len) {
641             snd_pcm_sframes_t written;
642 
643             written = snd_pcm_writei (alsa->handle, src, len);
644 
645             if (written <= 0) {
646                 switch (written) {
647                 case 0:
648                     trace_alsa_wrote_zero(len);
649                     return;
650 
651                 case -EPIPE:
652                     if (alsa_recover (alsa->handle)) {
653                         alsa_logerr (written, "Failed to write %d frames\n",
654                                      len);
655                         return;
656                     }
657                     trace_alsa_xrun_out();
658                     continue;
659 
660                 case -ESTRPIPE:
661                     /* stream is suspended and waiting for an
662                        application recovery */
663                     if (alsa_resume (alsa->handle)) {
664                         alsa_logerr (written, "Failed to write %d frames\n",
665                                      len);
666                         return;
667                     }
668                     trace_alsa_resume_out();
669                     continue;
670 
671                 case -EAGAIN:
672                     return;
673 
674                 default:
675                     alsa_logerr (written, "Failed to write %d frames from %p\n",
676                                  len, src);
677                     return;
678                 }
679             }
680 
681             alsa->wpos = (alsa->wpos + written) % hw->samples;
682             alsa->pending -= written;
683             len -= written;
684         }
685     }
686 }
687 
688 static int alsa_run_out (HWVoiceOut *hw, int live)
689 {
690     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
691     int decr;
692     snd_pcm_sframes_t avail;
693 
694     avail = alsa_get_avail (alsa->handle);
695     if (avail < 0) {
696         dolog ("Could not get number of available playback frames\n");
697         return 0;
698     }
699 
700     decr = audio_MIN (live, avail);
701     decr = audio_pcm_hw_clip_out (hw, alsa->pcm_buf, decr, alsa->pending);
702     alsa->pending += decr;
703     alsa_write_pending (alsa);
704     return decr;
705 }
706 
707 static void alsa_fini_out (HWVoiceOut *hw)
708 {
709     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
710 
711     ldebug ("alsa_fini\n");
712     alsa_anal_close (&alsa->handle, &alsa->pollhlp);
713 
714     g_free(alsa->pcm_buf);
715     alsa->pcm_buf = NULL;
716 }
717 
718 static int alsa_init_out(HWVoiceOut *hw, struct audsettings *as,
719                          void *drv_opaque)
720 {
721     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
722     struct alsa_params_req req;
723     struct alsa_params_obt obt;
724     snd_pcm_t *handle;
725     struct audsettings obt_as;
726     Audiodev *dev = drv_opaque;
727 
728     req.fmt = aud_to_alsafmt (as->fmt, as->endianness);
729     req.freq = as->freq;
730     req.nchannels = as->nchannels;
731 
732     if (alsa_open(0, &req, &obt, &handle, dev)) {
733         return -1;
734     }
735 
736     obt_as.freq = obt.freq;
737     obt_as.nchannels = obt.nchannels;
738     obt_as.fmt = obt.fmt;
739     obt_as.endianness = obt.endianness;
740 
741     audio_pcm_init_info (&hw->info, &obt_as);
742     hw->samples = obt.samples;
743 
744     alsa->pcm_buf = audio_calloc(__func__, obt.samples, 1 << hw->info.shift);
745     if (!alsa->pcm_buf) {
746         dolog ("Could not allocate DAC buffer (%d samples, each %d bytes)\n",
747                hw->samples, 1 << hw->info.shift);
748         alsa_anal_close1 (&handle);
749         return -1;
750     }
751 
752     alsa->handle = handle;
753     alsa->dev = dev;
754     return 0;
755 }
756 
757 #define VOICE_CTL_PAUSE 0
758 #define VOICE_CTL_PREPARE 1
759 #define VOICE_CTL_START 2
760 
761 static int alsa_voice_ctl (snd_pcm_t *handle, const char *typ, int ctl)
762 {
763     int err;
764 
765     if (ctl == VOICE_CTL_PAUSE) {
766         err = snd_pcm_drop (handle);
767         if (err < 0) {
768             alsa_logerr (err, "Could not stop %s\n", typ);
769             return -1;
770         }
771     }
772     else {
773         err = snd_pcm_prepare (handle);
774         if (err < 0) {
775             alsa_logerr (err, "Could not prepare handle for %s\n", typ);
776             return -1;
777         }
778         if (ctl == VOICE_CTL_START) {
779             err = snd_pcm_start(handle);
780             if (err < 0) {
781                 alsa_logerr (err, "Could not start handle for %s\n", typ);
782                 return -1;
783             }
784         }
785     }
786 
787     return 0;
788 }
789 
790 static int alsa_ctl_out (HWVoiceOut *hw, int cmd, ...)
791 {
792     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
793     AudiodevAlsaPerDirectionOptions *apdo = alsa->dev->u.alsa.out;
794 
795     switch (cmd) {
796     case VOICE_ENABLE:
797         {
798             bool poll_mode = apdo->try_poll;
799 
800             ldebug ("enabling voice\n");
801             if (poll_mode && alsa_poll_out (hw)) {
802                 poll_mode = 0;
803             }
804             hw->poll_mode = poll_mode;
805             return alsa_voice_ctl (alsa->handle, "playback", VOICE_CTL_PREPARE);
806         }
807 
808     case VOICE_DISABLE:
809         ldebug ("disabling voice\n");
810         if (hw->poll_mode) {
811             hw->poll_mode = 0;
812             alsa_fini_poll (&alsa->pollhlp);
813         }
814         return alsa_voice_ctl (alsa->handle, "playback", VOICE_CTL_PAUSE);
815     }
816 
817     return -1;
818 }
819 
820 static int alsa_init_in(HWVoiceIn *hw, struct audsettings *as, void *drv_opaque)
821 {
822     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
823     struct alsa_params_req req;
824     struct alsa_params_obt obt;
825     snd_pcm_t *handle;
826     struct audsettings obt_as;
827     Audiodev *dev = drv_opaque;
828 
829     req.fmt = aud_to_alsafmt (as->fmt, as->endianness);
830     req.freq = as->freq;
831     req.nchannels = as->nchannels;
832 
833     if (alsa_open(1, &req, &obt, &handle, dev)) {
834         return -1;
835     }
836 
837     obt_as.freq = obt.freq;
838     obt_as.nchannels = obt.nchannels;
839     obt_as.fmt = obt.fmt;
840     obt_as.endianness = obt.endianness;
841 
842     audio_pcm_init_info (&hw->info, &obt_as);
843     hw->samples = obt.samples;
844 
845     alsa->pcm_buf = audio_calloc(__func__, hw->samples, 1 << hw->info.shift);
846     if (!alsa->pcm_buf) {
847         dolog ("Could not allocate ADC buffer (%d samples, each %d bytes)\n",
848                hw->samples, 1 << hw->info.shift);
849         alsa_anal_close1 (&handle);
850         return -1;
851     }
852 
853     alsa->handle = handle;
854     alsa->dev = dev;
855     return 0;
856 }
857 
858 static void alsa_fini_in (HWVoiceIn *hw)
859 {
860     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
861 
862     alsa_anal_close (&alsa->handle, &alsa->pollhlp);
863 
864     g_free(alsa->pcm_buf);
865     alsa->pcm_buf = NULL;
866 }
867 
868 static int alsa_run_in (HWVoiceIn *hw)
869 {
870     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
871     int hwshift = hw->info.shift;
872     int i;
873     int live = audio_pcm_hw_get_live_in (hw);
874     int dead = hw->samples - live;
875     int decr;
876     struct {
877         int add;
878         int len;
879     } bufs[2] = {
880         { .add = hw->wpos, .len = 0 },
881         { .add = 0,        .len = 0 }
882     };
883     snd_pcm_sframes_t avail;
884     snd_pcm_uframes_t read_samples = 0;
885 
886     if (!dead) {
887         return 0;
888     }
889 
890     avail = alsa_get_avail (alsa->handle);
891     if (avail < 0) {
892         dolog ("Could not get number of captured frames\n");
893         return 0;
894     }
895 
896     if (!avail) {
897         snd_pcm_state_t state;
898 
899         state = snd_pcm_state (alsa->handle);
900         switch (state) {
901         case SND_PCM_STATE_PREPARED:
902             avail = hw->samples;
903             break;
904         case SND_PCM_STATE_SUSPENDED:
905             /* stream is suspended and waiting for an application recovery */
906             if (alsa_resume (alsa->handle)) {
907                 dolog ("Failed to resume suspended input stream\n");
908                 return 0;
909             }
910             trace_alsa_resume_in();
911             break;
912         default:
913             trace_alsa_no_frames(state);
914             return 0;
915         }
916     }
917 
918     decr = audio_MIN (dead, avail);
919     if (!decr) {
920         return 0;
921     }
922 
923     if (hw->wpos + decr > hw->samples) {
924         bufs[0].len = (hw->samples - hw->wpos);
925         bufs[1].len = (decr - (hw->samples - hw->wpos));
926     }
927     else {
928         bufs[0].len = decr;
929     }
930 
931     for (i = 0; i < 2; ++i) {
932         void *src;
933         struct st_sample *dst;
934         snd_pcm_sframes_t nread;
935         snd_pcm_uframes_t len;
936 
937         len = bufs[i].len;
938 
939         src = advance (alsa->pcm_buf, bufs[i].add << hwshift);
940         dst = hw->conv_buf + bufs[i].add;
941 
942         while (len) {
943             nread = snd_pcm_readi (alsa->handle, src, len);
944 
945             if (nread <= 0) {
946                 switch (nread) {
947                 case 0:
948                     trace_alsa_read_zero(len);
949                     goto exit;
950 
951                 case -EPIPE:
952                     if (alsa_recover (alsa->handle)) {
953                         alsa_logerr (nread, "Failed to read %ld frames\n", len);
954                         goto exit;
955                     }
956                     trace_alsa_xrun_in();
957                     continue;
958 
959                 case -EAGAIN:
960                     goto exit;
961 
962                 default:
963                     alsa_logerr (
964                         nread,
965                         "Failed to read %ld frames from %p\n",
966                         len,
967                         src
968                         );
969                     goto exit;
970                 }
971             }
972 
973             hw->conv (dst, src, nread);
974 
975             src = advance (src, nread << hwshift);
976             dst += nread;
977 
978             read_samples += nread;
979             len -= nread;
980         }
981     }
982 
983  exit:
984     hw->wpos = (hw->wpos + read_samples) % hw->samples;
985     return read_samples;
986 }
987 
988 static int alsa_read (SWVoiceIn *sw, void *buf, int size)
989 {
990     return audio_pcm_sw_read (sw, buf, size);
991 }
992 
993 static int alsa_ctl_in (HWVoiceIn *hw, int cmd, ...)
994 {
995     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
996     AudiodevAlsaPerDirectionOptions *apdo = alsa->dev->u.alsa.in;
997 
998     switch (cmd) {
999     case VOICE_ENABLE:
1000         {
1001             bool poll_mode = apdo->try_poll;
1002 
1003             ldebug ("enabling voice\n");
1004             if (poll_mode && alsa_poll_in (hw)) {
1005                 poll_mode = 0;
1006             }
1007             hw->poll_mode = poll_mode;
1008 
1009             return alsa_voice_ctl (alsa->handle, "capture", VOICE_CTL_START);
1010         }
1011 
1012     case VOICE_DISABLE:
1013         ldebug ("disabling voice\n");
1014         if (hw->poll_mode) {
1015             hw->poll_mode = 0;
1016             alsa_fini_poll (&alsa->pollhlp);
1017         }
1018         return alsa_voice_ctl (alsa->handle, "capture", VOICE_CTL_PAUSE);
1019     }
1020 
1021     return -1;
1022 }
1023 
1024 static void alsa_init_per_direction(AudiodevAlsaPerDirectionOptions *apdo)
1025 {
1026     if (!apdo->has_try_poll) {
1027         apdo->try_poll = true;
1028         apdo->has_try_poll = true;
1029     }
1030 }
1031 
1032 static void *alsa_audio_init(Audiodev *dev)
1033 {
1034     AudiodevAlsaOptions *aopts;
1035     assert(dev->driver == AUDIODEV_DRIVER_ALSA);
1036 
1037     aopts = &dev->u.alsa;
1038     alsa_init_per_direction(aopts->in);
1039     alsa_init_per_direction(aopts->out);
1040 
1041     /*
1042      * need to define them, as otherwise alsa produces no sound
1043      * doesn't set has_* so alsa_open can identify it wasn't set by the user
1044      */
1045     if (!dev->u.alsa.out->has_period_length) {
1046         /* 1024 frames assuming 44100Hz */
1047         dev->u.alsa.out->period_length = 1024 * 1000000 / 44100;
1048     }
1049     if (!dev->u.alsa.out->has_buffer_length) {
1050         /* 4096 frames assuming 44100Hz */
1051         dev->u.alsa.out->buffer_length = 4096ll * 1000000 / 44100;
1052     }
1053 
1054     /*
1055      * OptsVisitor sets unspecified optional fields to zero, but do not depend
1056      * on it...
1057      */
1058     if (!dev->u.alsa.in->has_period_length) {
1059         dev->u.alsa.in->period_length = 0;
1060     }
1061     if (!dev->u.alsa.in->has_buffer_length) {
1062         dev->u.alsa.in->buffer_length = 0;
1063     }
1064 
1065     return dev;
1066 }
1067 
1068 static void alsa_audio_fini (void *opaque)
1069 {
1070 }
1071 
1072 static struct audio_pcm_ops alsa_pcm_ops = {
1073     .init_out = alsa_init_out,
1074     .fini_out = alsa_fini_out,
1075     .run_out  = alsa_run_out,
1076     .write    = alsa_write,
1077     .ctl_out  = alsa_ctl_out,
1078 
1079     .init_in  = alsa_init_in,
1080     .fini_in  = alsa_fini_in,
1081     .run_in   = alsa_run_in,
1082     .read     = alsa_read,
1083     .ctl_in   = alsa_ctl_in,
1084 };
1085 
1086 static struct audio_driver alsa_audio_driver = {
1087     .name           = "alsa",
1088     .descr          = "ALSA http://www.alsa-project.org",
1089     .init           = alsa_audio_init,
1090     .fini           = alsa_audio_fini,
1091     .pcm_ops        = &alsa_pcm_ops,
1092     .can_be_default = 1,
1093     .max_voices_out = INT_MAX,
1094     .max_voices_in  = INT_MAX,
1095     .voice_size_out = sizeof (ALSAVoiceOut),
1096     .voice_size_in  = sizeof (ALSAVoiceIn)
1097 };
1098 
1099 static void register_audio_alsa(void)
1100 {
1101     audio_driver_register(&alsa_audio_driver);
1102 }
1103 type_init(register_audio_alsa);
1104