xref: /openbmc/qemu/audio/alsaaudio.c (revision 9f2d175d)
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 "qemu/osdep.h"
25 #include <alsa/asoundlib.h>
26 #include "qemu-common.h"
27 #include "qemu/main-loop.h"
28 #include "audio.h"
29 #include "trace.h"
30 
31 #if QEMU_GNUC_PREREQ(4, 3)
32 #pragma GCC diagnostic ignored "-Waddress"
33 #endif
34 
35 #define AUDIO_CAP "alsa"
36 #include "audio_int.h"
37 
38 typedef struct ALSAConf {
39     int size_in_usec_in;
40     int size_in_usec_out;
41     const char *pcm_name_in;
42     const char *pcm_name_out;
43     unsigned int buffer_size_in;
44     unsigned int period_size_in;
45     unsigned int buffer_size_out;
46     unsigned int period_size_out;
47     unsigned int threshold;
48 
49     int buffer_size_in_overridden;
50     int period_size_in_overridden;
51 
52     int buffer_size_out_overridden;
53     int period_size_out_overridden;
54 } ALSAConf;
55 
56 struct pollhlp {
57     snd_pcm_t *handle;
58     struct pollfd *pfds;
59     ALSAConf *conf;
60     int count;
61     int mask;
62 };
63 
64 typedef struct ALSAVoiceOut {
65     HWVoiceOut hw;
66     int wpos;
67     int pending;
68     void *pcm_buf;
69     snd_pcm_t *handle;
70     struct pollhlp pollhlp;
71 } ALSAVoiceOut;
72 
73 typedef struct ALSAVoiceIn {
74     HWVoiceIn hw;
75     snd_pcm_t *handle;
76     void *pcm_buf;
77     struct pollhlp pollhlp;
78 } ALSAVoiceIn;
79 
80 struct alsa_params_req {
81     int freq;
82     snd_pcm_format_t fmt;
83     int nchannels;
84     int size_in_usec;
85     int override_mask;
86     unsigned int buffer_size;
87     unsigned int period_size;
88 };
89 
90 struct alsa_params_obt {
91     int freq;
92     audfmt_e fmt;
93     int endianness;
94     int nchannels;
95     snd_pcm_uframes_t samples;
96 };
97 
98 static void GCC_FMT_ATTR (2, 3) alsa_logerr (int err, const char *fmt, ...)
99 {
100     va_list ap;
101 
102     va_start (ap, fmt);
103     AUD_vlog (AUDIO_CAP, fmt, ap);
104     va_end (ap);
105 
106     AUD_log (AUDIO_CAP, "Reason: %s\n", snd_strerror (err));
107 }
108 
109 static void GCC_FMT_ATTR (3, 4) alsa_logerr2 (
110     int err,
111     const char *typ,
112     const char *fmt,
113     ...
114     )
115 {
116     va_list ap;
117 
118     AUD_log (AUDIO_CAP, "Could not initialize %s\n", typ);
119 
120     va_start (ap, fmt);
121     AUD_vlog (AUDIO_CAP, fmt, ap);
122     va_end (ap);
123 
124     AUD_log (AUDIO_CAP, "Reason: %s\n", snd_strerror (err));
125 }
126 
127 static void alsa_fini_poll (struct pollhlp *hlp)
128 {
129     int i;
130     struct pollfd *pfds = hlp->pfds;
131 
132     if (pfds) {
133         for (i = 0; i < hlp->count; ++i) {
134             qemu_set_fd_handler (pfds[i].fd, NULL, NULL, NULL);
135         }
136         g_free (pfds);
137     }
138     hlp->pfds = NULL;
139     hlp->count = 0;
140     hlp->handle = NULL;
141 }
142 
143 static void alsa_anal_close1 (snd_pcm_t **handlep)
144 {
145     int err = snd_pcm_close (*handlep);
146     if (err) {
147         alsa_logerr (err, "Failed to close PCM handle %p\n", *handlep);
148     }
149     *handlep = NULL;
150 }
151 
152 static void alsa_anal_close (snd_pcm_t **handlep, struct pollhlp *hlp)
153 {
154     alsa_fini_poll (hlp);
155     alsa_anal_close1 (handlep);
156 }
157 
158 static int alsa_recover (snd_pcm_t *handle)
159 {
160     int err = snd_pcm_prepare (handle);
161     if (err < 0) {
162         alsa_logerr (err, "Failed to prepare handle %p\n", handle);
163         return -1;
164     }
165     return 0;
166 }
167 
168 static int alsa_resume (snd_pcm_t *handle)
169 {
170     int err = snd_pcm_resume (handle);
171     if (err < 0) {
172         alsa_logerr (err, "Failed to resume handle %p\n", handle);
173         return -1;
174     }
175     return 0;
176 }
177 
178 static void alsa_poll_handler (void *opaque)
179 {
180     int err, count;
181     snd_pcm_state_t state;
182     struct pollhlp *hlp = opaque;
183     unsigned short revents;
184 
185     count = poll (hlp->pfds, hlp->count, 0);
186     if (count < 0) {
187         dolog ("alsa_poll_handler: poll %s\n", strerror (errno));
188         return;
189     }
190 
191     if (!count) {
192         return;
193     }
194 
195     /* XXX: ALSA example uses initial count, not the one returned by
196        poll, correct? */
197     err = snd_pcm_poll_descriptors_revents (hlp->handle, hlp->pfds,
198                                             hlp->count, &revents);
199     if (err < 0) {
200         alsa_logerr (err, "snd_pcm_poll_descriptors_revents");
201         return;
202     }
203 
204     if (!(revents & hlp->mask)) {
205         trace_alsa_revents(revents);
206         return;
207     }
208 
209     state = snd_pcm_state (hlp->handle);
210     switch (state) {
211     case SND_PCM_STATE_SETUP:
212         alsa_recover (hlp->handle);
213         break;
214 
215     case SND_PCM_STATE_XRUN:
216         alsa_recover (hlp->handle);
217         break;
218 
219     case SND_PCM_STATE_SUSPENDED:
220         alsa_resume (hlp->handle);
221         break;
222 
223     case SND_PCM_STATE_PREPARED:
224         audio_run ("alsa run (prepared)");
225         break;
226 
227     case SND_PCM_STATE_RUNNING:
228         audio_run ("alsa run (running)");
229         break;
230 
231     default:
232         dolog ("Unexpected state %d\n", state);
233     }
234 }
235 
236 static int alsa_poll_helper (snd_pcm_t *handle, struct pollhlp *hlp, int mask)
237 {
238     int i, count, err;
239     struct pollfd *pfds;
240 
241     count = snd_pcm_poll_descriptors_count (handle);
242     if (count <= 0) {
243         dolog ("Could not initialize poll mode\n"
244                "Invalid number of poll descriptors %d\n", count);
245         return -1;
246     }
247 
248     pfds = audio_calloc ("alsa_poll_helper", count, sizeof (*pfds));
249     if (!pfds) {
250         dolog ("Could not initialize poll mode\n");
251         return -1;
252     }
253 
254     err = snd_pcm_poll_descriptors (handle, pfds, count);
255     if (err < 0) {
256         alsa_logerr (err, "Could not initialize poll mode\n"
257                      "Could not obtain poll descriptors\n");
258         g_free (pfds);
259         return -1;
260     }
261 
262     for (i = 0; i < count; ++i) {
263         if (pfds[i].events & POLLIN) {
264             qemu_set_fd_handler (pfds[i].fd, alsa_poll_handler, NULL, hlp);
265         }
266         if (pfds[i].events & POLLOUT) {
267             trace_alsa_pollout(i, pfds[i].fd);
268             qemu_set_fd_handler (pfds[i].fd, NULL, alsa_poll_handler, hlp);
269         }
270         trace_alsa_set_handler(pfds[i].events, i, pfds[i].fd, err);
271 
272     }
273     hlp->pfds = pfds;
274     hlp->count = count;
275     hlp->handle = handle;
276     hlp->mask = mask;
277     return 0;
278 }
279 
280 static int alsa_poll_out (HWVoiceOut *hw)
281 {
282     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
283 
284     return alsa_poll_helper (alsa->handle, &alsa->pollhlp, POLLOUT);
285 }
286 
287 static int alsa_poll_in (HWVoiceIn *hw)
288 {
289     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
290 
291     return alsa_poll_helper (alsa->handle, &alsa->pollhlp, POLLIN);
292 }
293 
294 static int alsa_write (SWVoiceOut *sw, void *buf, int len)
295 {
296     return audio_pcm_sw_write (sw, buf, len);
297 }
298 
299 static snd_pcm_format_t aud_to_alsafmt (audfmt_e fmt, int endianness)
300 {
301     switch (fmt) {
302     case AUD_FMT_S8:
303         return SND_PCM_FORMAT_S8;
304 
305     case AUD_FMT_U8:
306         return SND_PCM_FORMAT_U8;
307 
308     case AUD_FMT_S16:
309         if (endianness) {
310             return SND_PCM_FORMAT_S16_BE;
311         }
312         else {
313             return SND_PCM_FORMAT_S16_LE;
314         }
315 
316     case AUD_FMT_U16:
317         if (endianness) {
318             return SND_PCM_FORMAT_U16_BE;
319         }
320         else {
321             return SND_PCM_FORMAT_U16_LE;
322         }
323 
324     case AUD_FMT_S32:
325         if (endianness) {
326             return SND_PCM_FORMAT_S32_BE;
327         }
328         else {
329             return SND_PCM_FORMAT_S32_LE;
330         }
331 
332     case AUD_FMT_U32:
333         if (endianness) {
334             return SND_PCM_FORMAT_U32_BE;
335         }
336         else {
337             return SND_PCM_FORMAT_U32_LE;
338         }
339 
340     default:
341         dolog ("Internal logic error: Bad audio format %d\n", fmt);
342 #ifdef DEBUG_AUDIO
343         abort ();
344 #endif
345         return SND_PCM_FORMAT_U8;
346     }
347 }
348 
349 static int alsa_to_audfmt (snd_pcm_format_t alsafmt, audfmt_e *fmt,
350                            int *endianness)
351 {
352     switch (alsafmt) {
353     case SND_PCM_FORMAT_S8:
354         *endianness = 0;
355         *fmt = AUD_FMT_S8;
356         break;
357 
358     case SND_PCM_FORMAT_U8:
359         *endianness = 0;
360         *fmt = AUD_FMT_U8;
361         break;
362 
363     case SND_PCM_FORMAT_S16_LE:
364         *endianness = 0;
365         *fmt = AUD_FMT_S16;
366         break;
367 
368     case SND_PCM_FORMAT_U16_LE:
369         *endianness = 0;
370         *fmt = AUD_FMT_U16;
371         break;
372 
373     case SND_PCM_FORMAT_S16_BE:
374         *endianness = 1;
375         *fmt = AUD_FMT_S16;
376         break;
377 
378     case SND_PCM_FORMAT_U16_BE:
379         *endianness = 1;
380         *fmt = AUD_FMT_U16;
381         break;
382 
383     case SND_PCM_FORMAT_S32_LE:
384         *endianness = 0;
385         *fmt = AUD_FMT_S32;
386         break;
387 
388     case SND_PCM_FORMAT_U32_LE:
389         *endianness = 0;
390         *fmt = AUD_FMT_U32;
391         break;
392 
393     case SND_PCM_FORMAT_S32_BE:
394         *endianness = 1;
395         *fmt = AUD_FMT_S32;
396         break;
397 
398     case SND_PCM_FORMAT_U32_BE:
399         *endianness = 1;
400         *fmt = AUD_FMT_U32;
401         break;
402 
403     default:
404         dolog ("Unrecognized audio format %d\n", alsafmt);
405         return -1;
406     }
407 
408     return 0;
409 }
410 
411 static void alsa_dump_info (struct alsa_params_req *req,
412                             struct alsa_params_obt *obt,
413                             snd_pcm_format_t obtfmt)
414 {
415     dolog ("parameter | requested value | obtained value\n");
416     dolog ("format    |      %10d |     %10d\n", req->fmt, obtfmt);
417     dolog ("channels  |      %10d |     %10d\n",
418            req->nchannels, obt->nchannels);
419     dolog ("frequency |      %10d |     %10d\n", req->freq, obt->freq);
420     dolog ("============================================\n");
421     dolog ("requested: buffer size %d period size %d\n",
422            req->buffer_size, req->period_size);
423     dolog ("obtained: samples %ld\n", obt->samples);
424 }
425 
426 static void alsa_set_threshold (snd_pcm_t *handle, snd_pcm_uframes_t threshold)
427 {
428     int err;
429     snd_pcm_sw_params_t *sw_params;
430 
431     snd_pcm_sw_params_alloca (&sw_params);
432 
433     err = snd_pcm_sw_params_current (handle, sw_params);
434     if (err < 0) {
435         dolog ("Could not fully initialize DAC\n");
436         alsa_logerr (err, "Failed to get current software parameters\n");
437         return;
438     }
439 
440     err = snd_pcm_sw_params_set_start_threshold (handle, sw_params, threshold);
441     if (err < 0) {
442         dolog ("Could not fully initialize DAC\n");
443         alsa_logerr (err, "Failed to set software threshold to %ld\n",
444                      threshold);
445         return;
446     }
447 
448     err = snd_pcm_sw_params (handle, sw_params);
449     if (err < 0) {
450         dolog ("Could not fully initialize DAC\n");
451         alsa_logerr (err, "Failed to set software parameters\n");
452         return;
453     }
454 }
455 
456 static int alsa_open (int in, struct alsa_params_req *req,
457                       struct alsa_params_obt *obt, snd_pcm_t **handlep,
458                       ALSAConf *conf)
459 {
460     snd_pcm_t *handle;
461     snd_pcm_hw_params_t *hw_params;
462     int err;
463     int size_in_usec;
464     unsigned int freq, nchannels;
465     const char *pcm_name = in ? conf->pcm_name_in : conf->pcm_name_out;
466     snd_pcm_uframes_t obt_buffer_size;
467     const char *typ = in ? "ADC" : "DAC";
468     snd_pcm_format_t obtfmt;
469 
470     freq = req->freq;
471     nchannels = req->nchannels;
472     size_in_usec = req->size_in_usec;
473 
474     snd_pcm_hw_params_alloca (&hw_params);
475 
476     err = snd_pcm_open (
477         &handle,
478         pcm_name,
479         in ? SND_PCM_STREAM_CAPTURE : SND_PCM_STREAM_PLAYBACK,
480         SND_PCM_NONBLOCK
481         );
482     if (err < 0) {
483         alsa_logerr2 (err, typ, "Failed to open `%s':\n", pcm_name);
484         return -1;
485     }
486 
487     err = snd_pcm_hw_params_any (handle, hw_params);
488     if (err < 0) {
489         alsa_logerr2 (err, typ, "Failed to initialize hardware parameters\n");
490         goto err;
491     }
492 
493     err = snd_pcm_hw_params_set_access (
494         handle,
495         hw_params,
496         SND_PCM_ACCESS_RW_INTERLEAVED
497         );
498     if (err < 0) {
499         alsa_logerr2 (err, typ, "Failed to set access type\n");
500         goto err;
501     }
502 
503     err = snd_pcm_hw_params_set_format (handle, hw_params, req->fmt);
504     if (err < 0) {
505         alsa_logerr2 (err, typ, "Failed to set format %d\n", req->fmt);
506     }
507 
508     err = snd_pcm_hw_params_set_rate_near (handle, hw_params, &freq, 0);
509     if (err < 0) {
510         alsa_logerr2 (err, typ, "Failed to set frequency %d\n", req->freq);
511         goto err;
512     }
513 
514     err = snd_pcm_hw_params_set_channels_near (
515         handle,
516         hw_params,
517         &nchannels
518         );
519     if (err < 0) {
520         alsa_logerr2 (err, typ, "Failed to set number of channels %d\n",
521                       req->nchannels);
522         goto err;
523     }
524 
525     if (nchannels != 1 && nchannels != 2) {
526         alsa_logerr2 (err, typ,
527                       "Can not handle obtained number of channels %d\n",
528                       nchannels);
529         goto err;
530     }
531 
532     if (req->buffer_size) {
533         unsigned long obt;
534 
535         if (size_in_usec) {
536             int dir = 0;
537             unsigned int btime = req->buffer_size;
538 
539             err = snd_pcm_hw_params_set_buffer_time_near (
540                 handle,
541                 hw_params,
542                 &btime,
543                 &dir
544                 );
545             obt = btime;
546         }
547         else {
548             snd_pcm_uframes_t bsize = req->buffer_size;
549 
550             err = snd_pcm_hw_params_set_buffer_size_near (
551                 handle,
552                 hw_params,
553                 &bsize
554                 );
555             obt = bsize;
556         }
557         if (err < 0) {
558             alsa_logerr2 (err, typ, "Failed to set buffer %s to %d\n",
559                           size_in_usec ? "time" : "size", req->buffer_size);
560             goto err;
561         }
562 
563         if ((req->override_mask & 2) && (obt - req->buffer_size))
564             dolog ("Requested buffer %s %u was rejected, using %lu\n",
565                    size_in_usec ? "time" : "size", req->buffer_size, obt);
566     }
567 
568     if (req->period_size) {
569         unsigned long obt;
570 
571         if (size_in_usec) {
572             int dir = 0;
573             unsigned int ptime = req->period_size;
574 
575             err = snd_pcm_hw_params_set_period_time_near (
576                 handle,
577                 hw_params,
578                 &ptime,
579                 &dir
580                 );
581             obt = ptime;
582         }
583         else {
584             int dir = 0;
585             snd_pcm_uframes_t psize = req->period_size;
586 
587             err = snd_pcm_hw_params_set_period_size_near (
588                 handle,
589                 hw_params,
590                 &psize,
591                 &dir
592                 );
593             obt = psize;
594         }
595 
596         if (err < 0) {
597             alsa_logerr2 (err, typ, "Failed to set period %s to %d\n",
598                           size_in_usec ? "time" : "size", req->period_size);
599             goto err;
600         }
601 
602         if (((req->override_mask & 1) && (obt - req->period_size)))
603             dolog ("Requested period %s %u was rejected, using %lu\n",
604                    size_in_usec ? "time" : "size", req->period_size, obt);
605     }
606 
607     err = snd_pcm_hw_params (handle, hw_params);
608     if (err < 0) {
609         alsa_logerr2 (err, typ, "Failed to apply audio parameters\n");
610         goto err;
611     }
612 
613     err = snd_pcm_hw_params_get_buffer_size (hw_params, &obt_buffer_size);
614     if (err < 0) {
615         alsa_logerr2 (err, typ, "Failed to get buffer size\n");
616         goto err;
617     }
618 
619     err = snd_pcm_hw_params_get_format (hw_params, &obtfmt);
620     if (err < 0) {
621         alsa_logerr2 (err, typ, "Failed to get format\n");
622         goto err;
623     }
624 
625     if (alsa_to_audfmt (obtfmt, &obt->fmt, &obt->endianness)) {
626         dolog ("Invalid format was returned %d\n", obtfmt);
627         goto err;
628     }
629 
630     err = snd_pcm_prepare (handle);
631     if (err < 0) {
632         alsa_logerr2 (err, typ, "Could not prepare handle %p\n", handle);
633         goto err;
634     }
635 
636     if (!in && conf->threshold) {
637         snd_pcm_uframes_t threshold;
638         int bytes_per_sec;
639 
640         bytes_per_sec = freq << (nchannels == 2);
641 
642         switch (obt->fmt) {
643         case AUD_FMT_S8:
644         case AUD_FMT_U8:
645             break;
646 
647         case AUD_FMT_S16:
648         case AUD_FMT_U16:
649             bytes_per_sec <<= 1;
650             break;
651 
652         case AUD_FMT_S32:
653         case AUD_FMT_U32:
654             bytes_per_sec <<= 2;
655             break;
656         }
657 
658         threshold = (conf->threshold * bytes_per_sec) / 1000;
659         alsa_set_threshold (handle, threshold);
660     }
661 
662     obt->nchannels = nchannels;
663     obt->freq = freq;
664     obt->samples = obt_buffer_size;
665 
666     *handlep = handle;
667 
668     if (obtfmt != req->fmt ||
669          obt->nchannels != req->nchannels ||
670          obt->freq != req->freq) {
671         dolog ("Audio parameters for %s\n", typ);
672         alsa_dump_info (req, obt, obtfmt);
673     }
674 
675 #ifdef DEBUG
676     alsa_dump_info (req, obt, obtfmt);
677 #endif
678     return 0;
679 
680  err:
681     alsa_anal_close1 (&handle);
682     return -1;
683 }
684 
685 static snd_pcm_sframes_t alsa_get_avail (snd_pcm_t *handle)
686 {
687     snd_pcm_sframes_t avail;
688 
689     avail = snd_pcm_avail_update (handle);
690     if (avail < 0) {
691         if (avail == -EPIPE) {
692             if (!alsa_recover (handle)) {
693                 avail = snd_pcm_avail_update (handle);
694             }
695         }
696 
697         if (avail < 0) {
698             alsa_logerr (avail,
699                          "Could not obtain number of available frames\n");
700             return -1;
701         }
702     }
703 
704     return avail;
705 }
706 
707 static void alsa_write_pending (ALSAVoiceOut *alsa)
708 {
709     HWVoiceOut *hw = &alsa->hw;
710 
711     while (alsa->pending) {
712         int left_till_end_samples = hw->samples - alsa->wpos;
713         int len = audio_MIN (alsa->pending, left_till_end_samples);
714         char *src = advance (alsa->pcm_buf, alsa->wpos << hw->info.shift);
715 
716         while (len) {
717             snd_pcm_sframes_t written;
718 
719             written = snd_pcm_writei (alsa->handle, src, len);
720 
721             if (written <= 0) {
722                 switch (written) {
723                 case 0:
724                     trace_alsa_wrote_zero(len);
725                     return;
726 
727                 case -EPIPE:
728                     if (alsa_recover (alsa->handle)) {
729                         alsa_logerr (written, "Failed to write %d frames\n",
730                                      len);
731                         return;
732                     }
733                     trace_alsa_xrun_out();
734                     continue;
735 
736                 case -ESTRPIPE:
737                     /* stream is suspended and waiting for an
738                        application recovery */
739                     if (alsa_resume (alsa->handle)) {
740                         alsa_logerr (written, "Failed to write %d frames\n",
741                                      len);
742                         return;
743                     }
744                     trace_alsa_resume_out();
745                     continue;
746 
747                 case -EAGAIN:
748                     return;
749 
750                 default:
751                     alsa_logerr (written, "Failed to write %d frames from %p\n",
752                                  len, src);
753                     return;
754                 }
755             }
756 
757             alsa->wpos = (alsa->wpos + written) % hw->samples;
758             alsa->pending -= written;
759             len -= written;
760         }
761     }
762 }
763 
764 static int alsa_run_out (HWVoiceOut *hw, int live)
765 {
766     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
767     int decr;
768     snd_pcm_sframes_t avail;
769 
770     avail = alsa_get_avail (alsa->handle);
771     if (avail < 0) {
772         dolog ("Could not get number of available playback frames\n");
773         return 0;
774     }
775 
776     decr = audio_MIN (live, avail);
777     decr = audio_pcm_hw_clip_out (hw, alsa->pcm_buf, decr, alsa->pending);
778     alsa->pending += decr;
779     alsa_write_pending (alsa);
780     return decr;
781 }
782 
783 static void alsa_fini_out (HWVoiceOut *hw)
784 {
785     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
786 
787     ldebug ("alsa_fini\n");
788     alsa_anal_close (&alsa->handle, &alsa->pollhlp);
789 
790     g_free(alsa->pcm_buf);
791     alsa->pcm_buf = NULL;
792 }
793 
794 static int alsa_init_out(HWVoiceOut *hw, struct audsettings *as,
795                          void *drv_opaque)
796 {
797     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
798     struct alsa_params_req req;
799     struct alsa_params_obt obt;
800     snd_pcm_t *handle;
801     struct audsettings obt_as;
802     ALSAConf *conf = drv_opaque;
803 
804     req.fmt = aud_to_alsafmt (as->fmt, as->endianness);
805     req.freq = as->freq;
806     req.nchannels = as->nchannels;
807     req.period_size = conf->period_size_out;
808     req.buffer_size = conf->buffer_size_out;
809     req.size_in_usec = conf->size_in_usec_out;
810     req.override_mask =
811         (conf->period_size_out_overridden ? 1 : 0) |
812         (conf->buffer_size_out_overridden ? 2 : 0);
813 
814     if (alsa_open (0, &req, &obt, &handle, conf)) {
815         return -1;
816     }
817 
818     obt_as.freq = obt.freq;
819     obt_as.nchannels = obt.nchannels;
820     obt_as.fmt = obt.fmt;
821     obt_as.endianness = obt.endianness;
822 
823     audio_pcm_init_info (&hw->info, &obt_as);
824     hw->samples = obt.samples;
825 
826     alsa->pcm_buf = audio_calloc(__func__, obt.samples, 1 << hw->info.shift);
827     if (!alsa->pcm_buf) {
828         dolog ("Could not allocate DAC buffer (%d samples, each %d bytes)\n",
829                hw->samples, 1 << hw->info.shift);
830         alsa_anal_close1 (&handle);
831         return -1;
832     }
833 
834     alsa->handle = handle;
835     alsa->pollhlp.conf = conf;
836     return 0;
837 }
838 
839 #define VOICE_CTL_PAUSE 0
840 #define VOICE_CTL_PREPARE 1
841 #define VOICE_CTL_START 2
842 
843 static int alsa_voice_ctl (snd_pcm_t *handle, const char *typ, int ctl)
844 {
845     int err;
846 
847     if (ctl == VOICE_CTL_PAUSE) {
848         err = snd_pcm_drop (handle);
849         if (err < 0) {
850             alsa_logerr (err, "Could not stop %s\n", typ);
851             return -1;
852         }
853     }
854     else {
855         err = snd_pcm_prepare (handle);
856         if (err < 0) {
857             alsa_logerr (err, "Could not prepare handle for %s\n", typ);
858             return -1;
859         }
860         if (ctl == VOICE_CTL_START) {
861             err = snd_pcm_start(handle);
862             if (err < 0) {
863                 alsa_logerr (err, "Could not start handle for %s\n", typ);
864                 return -1;
865             }
866         }
867     }
868 
869     return 0;
870 }
871 
872 static int alsa_ctl_out (HWVoiceOut *hw, int cmd, ...)
873 {
874     ALSAVoiceOut *alsa = (ALSAVoiceOut *) hw;
875 
876     switch (cmd) {
877     case VOICE_ENABLE:
878         {
879             va_list ap;
880             int poll_mode;
881 
882             va_start (ap, cmd);
883             poll_mode = va_arg (ap, int);
884             va_end (ap);
885 
886             ldebug ("enabling voice\n");
887             if (poll_mode && alsa_poll_out (hw)) {
888                 poll_mode = 0;
889             }
890             hw->poll_mode = poll_mode;
891             return alsa_voice_ctl (alsa->handle, "playback", VOICE_CTL_PREPARE);
892         }
893 
894     case VOICE_DISABLE:
895         ldebug ("disabling voice\n");
896         if (hw->poll_mode) {
897             hw->poll_mode = 0;
898             alsa_fini_poll (&alsa->pollhlp);
899         }
900         return alsa_voice_ctl (alsa->handle, "playback", VOICE_CTL_PAUSE);
901     }
902 
903     return -1;
904 }
905 
906 static int alsa_init_in(HWVoiceIn *hw, struct audsettings *as, void *drv_opaque)
907 {
908     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
909     struct alsa_params_req req;
910     struct alsa_params_obt obt;
911     snd_pcm_t *handle;
912     struct audsettings obt_as;
913     ALSAConf *conf = drv_opaque;
914 
915     req.fmt = aud_to_alsafmt (as->fmt, as->endianness);
916     req.freq = as->freq;
917     req.nchannels = as->nchannels;
918     req.period_size = conf->period_size_in;
919     req.buffer_size = conf->buffer_size_in;
920     req.size_in_usec = conf->size_in_usec_in;
921     req.override_mask =
922         (conf->period_size_in_overridden ? 1 : 0) |
923         (conf->buffer_size_in_overridden ? 2 : 0);
924 
925     if (alsa_open (1, &req, &obt, &handle, conf)) {
926         return -1;
927     }
928 
929     obt_as.freq = obt.freq;
930     obt_as.nchannels = obt.nchannels;
931     obt_as.fmt = obt.fmt;
932     obt_as.endianness = obt.endianness;
933 
934     audio_pcm_init_info (&hw->info, &obt_as);
935     hw->samples = obt.samples;
936 
937     alsa->pcm_buf = audio_calloc(__func__, hw->samples, 1 << hw->info.shift);
938     if (!alsa->pcm_buf) {
939         dolog ("Could not allocate ADC buffer (%d samples, each %d bytes)\n",
940                hw->samples, 1 << hw->info.shift);
941         alsa_anal_close1 (&handle);
942         return -1;
943     }
944 
945     alsa->handle = handle;
946     alsa->pollhlp.conf = conf;
947     return 0;
948 }
949 
950 static void alsa_fini_in (HWVoiceIn *hw)
951 {
952     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
953 
954     alsa_anal_close (&alsa->handle, &alsa->pollhlp);
955 
956     g_free(alsa->pcm_buf);
957     alsa->pcm_buf = NULL;
958 }
959 
960 static int alsa_run_in (HWVoiceIn *hw)
961 {
962     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
963     int hwshift = hw->info.shift;
964     int i;
965     int live = audio_pcm_hw_get_live_in (hw);
966     int dead = hw->samples - live;
967     int decr;
968     struct {
969         int add;
970         int len;
971     } bufs[2] = {
972         { .add = hw->wpos, .len = 0 },
973         { .add = 0,        .len = 0 }
974     };
975     snd_pcm_sframes_t avail;
976     snd_pcm_uframes_t read_samples = 0;
977 
978     if (!dead) {
979         return 0;
980     }
981 
982     avail = alsa_get_avail (alsa->handle);
983     if (avail < 0) {
984         dolog ("Could not get number of captured frames\n");
985         return 0;
986     }
987 
988     if (!avail) {
989         snd_pcm_state_t state;
990 
991         state = snd_pcm_state (alsa->handle);
992         switch (state) {
993         case SND_PCM_STATE_PREPARED:
994             avail = hw->samples;
995             break;
996         case SND_PCM_STATE_SUSPENDED:
997             /* stream is suspended and waiting for an application recovery */
998             if (alsa_resume (alsa->handle)) {
999                 dolog ("Failed to resume suspended input stream\n");
1000                 return 0;
1001             }
1002             trace_alsa_resume_in();
1003             break;
1004         default:
1005             trace_alsa_no_frames(state);
1006             return 0;
1007         }
1008     }
1009 
1010     decr = audio_MIN (dead, avail);
1011     if (!decr) {
1012         return 0;
1013     }
1014 
1015     if (hw->wpos + decr > hw->samples) {
1016         bufs[0].len = (hw->samples - hw->wpos);
1017         bufs[1].len = (decr - (hw->samples - hw->wpos));
1018     }
1019     else {
1020         bufs[0].len = decr;
1021     }
1022 
1023     for (i = 0; i < 2; ++i) {
1024         void *src;
1025         struct st_sample *dst;
1026         snd_pcm_sframes_t nread;
1027         snd_pcm_uframes_t len;
1028 
1029         len = bufs[i].len;
1030 
1031         src = advance (alsa->pcm_buf, bufs[i].add << hwshift);
1032         dst = hw->conv_buf + bufs[i].add;
1033 
1034         while (len) {
1035             nread = snd_pcm_readi (alsa->handle, src, len);
1036 
1037             if (nread <= 0) {
1038                 switch (nread) {
1039                 case 0:
1040                     trace_alsa_read_zero(len);
1041                     goto exit;
1042 
1043                 case -EPIPE:
1044                     if (alsa_recover (alsa->handle)) {
1045                         alsa_logerr (nread, "Failed to read %ld frames\n", len);
1046                         goto exit;
1047                     }
1048                     trace_alsa_xrun_in();
1049                     continue;
1050 
1051                 case -EAGAIN:
1052                     goto exit;
1053 
1054                 default:
1055                     alsa_logerr (
1056                         nread,
1057                         "Failed to read %ld frames from %p\n",
1058                         len,
1059                         src
1060                         );
1061                     goto exit;
1062                 }
1063             }
1064 
1065             hw->conv (dst, src, nread);
1066 
1067             src = advance (src, nread << hwshift);
1068             dst += nread;
1069 
1070             read_samples += nread;
1071             len -= nread;
1072         }
1073     }
1074 
1075  exit:
1076     hw->wpos = (hw->wpos + read_samples) % hw->samples;
1077     return read_samples;
1078 }
1079 
1080 static int alsa_read (SWVoiceIn *sw, void *buf, int size)
1081 {
1082     return audio_pcm_sw_read (sw, buf, size);
1083 }
1084 
1085 static int alsa_ctl_in (HWVoiceIn *hw, int cmd, ...)
1086 {
1087     ALSAVoiceIn *alsa = (ALSAVoiceIn *) hw;
1088 
1089     switch (cmd) {
1090     case VOICE_ENABLE:
1091         {
1092             va_list ap;
1093             int poll_mode;
1094 
1095             va_start (ap, cmd);
1096             poll_mode = va_arg (ap, int);
1097             va_end (ap);
1098 
1099             ldebug ("enabling voice\n");
1100             if (poll_mode && alsa_poll_in (hw)) {
1101                 poll_mode = 0;
1102             }
1103             hw->poll_mode = poll_mode;
1104 
1105             return alsa_voice_ctl (alsa->handle, "capture", VOICE_CTL_START);
1106         }
1107 
1108     case VOICE_DISABLE:
1109         ldebug ("disabling voice\n");
1110         if (hw->poll_mode) {
1111             hw->poll_mode = 0;
1112             alsa_fini_poll (&alsa->pollhlp);
1113         }
1114         return alsa_voice_ctl (alsa->handle, "capture", VOICE_CTL_PAUSE);
1115     }
1116 
1117     return -1;
1118 }
1119 
1120 static ALSAConf glob_conf = {
1121     .buffer_size_out = 4096,
1122     .period_size_out = 1024,
1123     .pcm_name_out = "default",
1124     .pcm_name_in = "default",
1125 };
1126 
1127 static void *alsa_audio_init (void)
1128 {
1129     ALSAConf *conf = g_malloc(sizeof(ALSAConf));
1130     *conf = glob_conf;
1131     return conf;
1132 }
1133 
1134 static void alsa_audio_fini (void *opaque)
1135 {
1136     g_free(opaque);
1137 }
1138 
1139 static struct audio_option alsa_options[] = {
1140     {
1141         .name        = "DAC_SIZE_IN_USEC",
1142         .tag         = AUD_OPT_BOOL,
1143         .valp        = &glob_conf.size_in_usec_out,
1144         .descr       = "DAC period/buffer size in microseconds (otherwise in frames)"
1145     },
1146     {
1147         .name        = "DAC_PERIOD_SIZE",
1148         .tag         = AUD_OPT_INT,
1149         .valp        = &glob_conf.period_size_out,
1150         .descr       = "DAC period size (0 to go with system default)",
1151         .overriddenp = &glob_conf.period_size_out_overridden
1152     },
1153     {
1154         .name        = "DAC_BUFFER_SIZE",
1155         .tag         = AUD_OPT_INT,
1156         .valp        = &glob_conf.buffer_size_out,
1157         .descr       = "DAC buffer size (0 to go with system default)",
1158         .overriddenp = &glob_conf.buffer_size_out_overridden
1159     },
1160     {
1161         .name        = "ADC_SIZE_IN_USEC",
1162         .tag         = AUD_OPT_BOOL,
1163         .valp        = &glob_conf.size_in_usec_in,
1164         .descr       =
1165         "ADC period/buffer size in microseconds (otherwise in frames)"
1166     },
1167     {
1168         .name        = "ADC_PERIOD_SIZE",
1169         .tag         = AUD_OPT_INT,
1170         .valp        = &glob_conf.period_size_in,
1171         .descr       = "ADC period size (0 to go with system default)",
1172         .overriddenp = &glob_conf.period_size_in_overridden
1173     },
1174     {
1175         .name        = "ADC_BUFFER_SIZE",
1176         .tag         = AUD_OPT_INT,
1177         .valp        = &glob_conf.buffer_size_in,
1178         .descr       = "ADC buffer size (0 to go with system default)",
1179         .overriddenp = &glob_conf.buffer_size_in_overridden
1180     },
1181     {
1182         .name        = "THRESHOLD",
1183         .tag         = AUD_OPT_INT,
1184         .valp        = &glob_conf.threshold,
1185         .descr       = "(undocumented)"
1186     },
1187     {
1188         .name        = "DAC_DEV",
1189         .tag         = AUD_OPT_STR,
1190         .valp        = &glob_conf.pcm_name_out,
1191         .descr       = "DAC device name (for instance dmix)"
1192     },
1193     {
1194         .name        = "ADC_DEV",
1195         .tag         = AUD_OPT_STR,
1196         .valp        = &glob_conf.pcm_name_in,
1197         .descr       = "ADC device name"
1198     },
1199     { /* End of list */ }
1200 };
1201 
1202 static struct audio_pcm_ops alsa_pcm_ops = {
1203     .init_out = alsa_init_out,
1204     .fini_out = alsa_fini_out,
1205     .run_out  = alsa_run_out,
1206     .write    = alsa_write,
1207     .ctl_out  = alsa_ctl_out,
1208 
1209     .init_in  = alsa_init_in,
1210     .fini_in  = alsa_fini_in,
1211     .run_in   = alsa_run_in,
1212     .read     = alsa_read,
1213     .ctl_in   = alsa_ctl_in,
1214 };
1215 
1216 static struct audio_driver alsa_audio_driver = {
1217     .name           = "alsa",
1218     .descr          = "ALSA http://www.alsa-project.org",
1219     .options        = alsa_options,
1220     .init           = alsa_audio_init,
1221     .fini           = alsa_audio_fini,
1222     .pcm_ops        = &alsa_pcm_ops,
1223     .can_be_default = 1,
1224     .max_voices_out = INT_MAX,
1225     .max_voices_in  = INT_MAX,
1226     .voice_size_out = sizeof (ALSAVoiceOut),
1227     .voice_size_in  = sizeof (ALSAVoiceIn)
1228 };
1229 
1230 static void register_audio_alsa(void)
1231 {
1232     audio_driver_register(&alsa_audio_driver);
1233 }
1234 type_init(register_audio_alsa);
1235