xref: /openbmc/qemu/audio/ossaudio.c (revision f1020c2c)
1 /*
2  * QEMU OSS audio driver
3  *
4  * Copyright (c) 2003-2005 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 <sys/ioctl.h>
26 #include <sys/soundcard.h>
27 #include "qemu-common.h"
28 #include "qemu/main-loop.h"
29 #include "qemu/host-utils.h"
30 #include "audio.h"
31 #include "trace.h"
32 
33 #define AUDIO_CAP "oss"
34 #include "audio_int.h"
35 
36 #if defined OSS_GETVERSION && defined SNDCTL_DSP_POLICY
37 #define USE_DSP_POLICY
38 #endif
39 
40 typedef struct OSSConf {
41     int try_mmap;
42     int nfrags;
43     int fragsize;
44     const char *devpath_out;
45     const char *devpath_in;
46     int exclusive;
47     int policy;
48 } OSSConf;
49 
50 typedef struct OSSVoiceOut {
51     HWVoiceOut hw;
52     void *pcm_buf;
53     int fd;
54     int wpos;
55     int nfrags;
56     int fragsize;
57     int mmapped;
58     int pending;
59     OSSConf *conf;
60 } OSSVoiceOut;
61 
62 typedef struct OSSVoiceIn {
63     HWVoiceIn hw;
64     void *pcm_buf;
65     int fd;
66     int nfrags;
67     int fragsize;
68     OSSConf *conf;
69 } OSSVoiceIn;
70 
71 struct oss_params {
72     int freq;
73     audfmt_e fmt;
74     int nchannels;
75     int nfrags;
76     int fragsize;
77 };
78 
79 static void GCC_FMT_ATTR (2, 3) oss_logerr (int err, const char *fmt, ...)
80 {
81     va_list ap;
82 
83     va_start (ap, fmt);
84     AUD_vlog (AUDIO_CAP, fmt, ap);
85     va_end (ap);
86 
87     AUD_log (AUDIO_CAP, "Reason: %s\n", strerror (err));
88 }
89 
90 static void GCC_FMT_ATTR (3, 4) oss_logerr2 (
91     int err,
92     const char *typ,
93     const char *fmt,
94     ...
95     )
96 {
97     va_list ap;
98 
99     AUD_log (AUDIO_CAP, "Could not initialize %s\n", typ);
100 
101     va_start (ap, fmt);
102     AUD_vlog (AUDIO_CAP, fmt, ap);
103     va_end (ap);
104 
105     AUD_log (AUDIO_CAP, "Reason: %s\n", strerror (err));
106 }
107 
108 static void oss_anal_close (int *fdp)
109 {
110     int err;
111 
112     qemu_set_fd_handler (*fdp, NULL, NULL, NULL);
113     err = close (*fdp);
114     if (err) {
115         oss_logerr (errno, "Failed to close file(fd=%d)\n", *fdp);
116     }
117     *fdp = -1;
118 }
119 
120 static void oss_helper_poll_out (void *opaque)
121 {
122     (void) opaque;
123     audio_run ("oss_poll_out");
124 }
125 
126 static void oss_helper_poll_in (void *opaque)
127 {
128     (void) opaque;
129     audio_run ("oss_poll_in");
130 }
131 
132 static void oss_poll_out (HWVoiceOut *hw)
133 {
134     OSSVoiceOut *oss = (OSSVoiceOut *) hw;
135 
136     qemu_set_fd_handler (oss->fd, NULL, oss_helper_poll_out, NULL);
137 }
138 
139 static void oss_poll_in (HWVoiceIn *hw)
140 {
141     OSSVoiceIn *oss = (OSSVoiceIn *) hw;
142 
143     qemu_set_fd_handler (oss->fd, oss_helper_poll_in, NULL, NULL);
144 }
145 
146 static int oss_write (SWVoiceOut *sw, void *buf, int len)
147 {
148     return audio_pcm_sw_write (sw, buf, len);
149 }
150 
151 static int aud_to_ossfmt (audfmt_e fmt, int endianness)
152 {
153     switch (fmt) {
154     case AUD_FMT_S8:
155         return AFMT_S8;
156 
157     case AUD_FMT_U8:
158         return AFMT_U8;
159 
160     case AUD_FMT_S16:
161         if (endianness) {
162             return AFMT_S16_BE;
163         }
164         else {
165             return AFMT_S16_LE;
166         }
167 
168     case AUD_FMT_U16:
169         if (endianness) {
170             return AFMT_U16_BE;
171         }
172         else {
173             return AFMT_U16_LE;
174         }
175 
176     default:
177         dolog ("Internal logic error: Bad audio format %d\n", fmt);
178 #ifdef DEBUG_AUDIO
179         abort ();
180 #endif
181         return AFMT_U8;
182     }
183 }
184 
185 static int oss_to_audfmt (int ossfmt, audfmt_e *fmt, int *endianness)
186 {
187     switch (ossfmt) {
188     case AFMT_S8:
189         *endianness = 0;
190         *fmt = AUD_FMT_S8;
191         break;
192 
193     case AFMT_U8:
194         *endianness = 0;
195         *fmt = AUD_FMT_U8;
196         break;
197 
198     case AFMT_S16_LE:
199         *endianness = 0;
200         *fmt = AUD_FMT_S16;
201         break;
202 
203     case AFMT_U16_LE:
204         *endianness = 0;
205         *fmt = AUD_FMT_U16;
206         break;
207 
208     case AFMT_S16_BE:
209         *endianness = 1;
210         *fmt = AUD_FMT_S16;
211         break;
212 
213     case AFMT_U16_BE:
214         *endianness = 1;
215         *fmt = AUD_FMT_U16;
216         break;
217 
218     default:
219         dolog ("Unrecognized audio format %d\n", ossfmt);
220         return -1;
221     }
222 
223     return 0;
224 }
225 
226 #if defined DEBUG_MISMATCHES || defined DEBUG
227 static void oss_dump_info (struct oss_params *req, struct oss_params *obt)
228 {
229     dolog ("parameter | requested value | obtained value\n");
230     dolog ("format    |      %10d |     %10d\n", req->fmt, obt->fmt);
231     dolog ("channels  |      %10d |     %10d\n",
232            req->nchannels, obt->nchannels);
233     dolog ("frequency |      %10d |     %10d\n", req->freq, obt->freq);
234     dolog ("nfrags    |      %10d |     %10d\n", req->nfrags, obt->nfrags);
235     dolog ("fragsize  |      %10d |     %10d\n",
236            req->fragsize, obt->fragsize);
237 }
238 #endif
239 
240 #ifdef USE_DSP_POLICY
241 static int oss_get_version (int fd, int *version, const char *typ)
242 {
243     if (ioctl (fd, OSS_GETVERSION, &version)) {
244 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
245         /*
246          * Looks like atm (20100109) FreeBSD knows OSS_GETVERSION
247          * since 7.x, but currently only on the mixer device (or in
248          * the Linuxolator), and in the native version that part of
249          * the code is in fact never reached so the ioctl fails anyway.
250          * Until this is fixed, just check the errno and if its what
251          * FreeBSD's sound drivers return atm assume they are new enough.
252          */
253         if (errno == EINVAL) {
254             *version = 0x040000;
255             return 0;
256         }
257 #endif
258         oss_logerr2 (errno, typ, "Failed to get OSS version\n");
259         return -1;
260     }
261     return 0;
262 }
263 #endif
264 
265 static int oss_open (int in, struct oss_params *req,
266                      struct oss_params *obt, int *pfd, OSSConf* conf)
267 {
268     int fd;
269     int oflags = conf->exclusive ? O_EXCL : 0;
270     audio_buf_info abinfo;
271     int fmt, freq, nchannels;
272     int setfragment = 1;
273     const char *dspname = in ? conf->devpath_in : conf->devpath_out;
274     const char *typ = in ? "ADC" : "DAC";
275 
276     /* Kludge needed to have working mmap on Linux */
277     oflags |= conf->try_mmap ? O_RDWR : (in ? O_RDONLY : O_WRONLY);
278 
279     fd = open (dspname, oflags | O_NONBLOCK);
280     if (-1 == fd) {
281         oss_logerr2 (errno, typ, "Failed to open `%s'\n", dspname);
282         return -1;
283     }
284 
285     freq = req->freq;
286     nchannels = req->nchannels;
287     fmt = req->fmt;
288 
289     if (ioctl (fd, SNDCTL_DSP_SAMPLESIZE, &fmt)) {
290         oss_logerr2 (errno, typ, "Failed to set sample size %d\n", req->fmt);
291         goto err;
292     }
293 
294     if (ioctl (fd, SNDCTL_DSP_CHANNELS, &nchannels)) {
295         oss_logerr2 (errno, typ, "Failed to set number of channels %d\n",
296                      req->nchannels);
297         goto err;
298     }
299 
300     if (ioctl (fd, SNDCTL_DSP_SPEED, &freq)) {
301         oss_logerr2 (errno, typ, "Failed to set frequency %d\n", req->freq);
302         goto err;
303     }
304 
305     if (ioctl (fd, SNDCTL_DSP_NONBLOCK, NULL)) {
306         oss_logerr2 (errno, typ, "Failed to set non-blocking mode\n");
307         goto err;
308     }
309 
310 #ifdef USE_DSP_POLICY
311     if (conf->policy >= 0) {
312         int version;
313 
314         if (!oss_get_version (fd, &version, typ)) {
315             trace_oss_version(version);
316 
317             if (version >= 0x040000) {
318                 int policy = conf->policy;
319                 if (ioctl (fd, SNDCTL_DSP_POLICY, &policy)) {
320                     oss_logerr2 (errno, typ,
321                                  "Failed to set timing policy to %d\n",
322                                  conf->policy);
323                     goto err;
324                 }
325                 setfragment = 0;
326             }
327         }
328     }
329 #endif
330 
331     if (setfragment) {
332         int mmmmssss = (req->nfrags << 16) | ctz32 (req->fragsize);
333         if (ioctl (fd, SNDCTL_DSP_SETFRAGMENT, &mmmmssss)) {
334             oss_logerr2 (errno, typ, "Failed to set buffer length (%d, %d)\n",
335                          req->nfrags, req->fragsize);
336             goto err;
337         }
338     }
339 
340     if (ioctl (fd, in ? SNDCTL_DSP_GETISPACE : SNDCTL_DSP_GETOSPACE, &abinfo)) {
341         oss_logerr2 (errno, typ, "Failed to get buffer length\n");
342         goto err;
343     }
344 
345     if (!abinfo.fragstotal || !abinfo.fragsize) {
346         AUD_log (AUDIO_CAP, "Returned bogus buffer information(%d, %d) for %s\n",
347                  abinfo.fragstotal, abinfo.fragsize, typ);
348         goto err;
349     }
350 
351     obt->fmt = fmt;
352     obt->nchannels = nchannels;
353     obt->freq = freq;
354     obt->nfrags = abinfo.fragstotal;
355     obt->fragsize = abinfo.fragsize;
356     *pfd = fd;
357 
358 #ifdef DEBUG_MISMATCHES
359     if ((req->fmt != obt->fmt) ||
360         (req->nchannels != obt->nchannels) ||
361         (req->freq != obt->freq) ||
362         (req->fragsize != obt->fragsize) ||
363         (req->nfrags != obt->nfrags)) {
364         dolog ("Audio parameters mismatch\n");
365         oss_dump_info (req, obt);
366     }
367 #endif
368 
369 #ifdef DEBUG
370     oss_dump_info (req, obt);
371 #endif
372     return 0;
373 
374  err:
375     oss_anal_close (&fd);
376     return -1;
377 }
378 
379 static void oss_write_pending (OSSVoiceOut *oss)
380 {
381     HWVoiceOut *hw = &oss->hw;
382 
383     if (oss->mmapped) {
384         return;
385     }
386 
387     while (oss->pending) {
388         int samples_written;
389         ssize_t bytes_written;
390         int samples_till_end = hw->samples - oss->wpos;
391         int samples_to_write = audio_MIN (oss->pending, samples_till_end);
392         int bytes_to_write = samples_to_write << hw->info.shift;
393         void *pcm = advance (oss->pcm_buf, oss->wpos << hw->info.shift);
394 
395         bytes_written = write (oss->fd, pcm, bytes_to_write);
396         if (bytes_written < 0) {
397             if (errno != EAGAIN) {
398                 oss_logerr (errno, "failed to write %d bytes\n",
399                             bytes_to_write);
400             }
401             break;
402         }
403 
404         if (bytes_written & hw->info.align) {
405             dolog ("misaligned write asked for %d, but got %zd\n",
406                    bytes_to_write, bytes_written);
407             return;
408         }
409 
410         samples_written = bytes_written >> hw->info.shift;
411         oss->pending -= samples_written;
412         oss->wpos = (oss->wpos + samples_written) % hw->samples;
413         if (bytes_written - bytes_to_write) {
414             break;
415         }
416     }
417 }
418 
419 static int oss_run_out (HWVoiceOut *hw, int live)
420 {
421     OSSVoiceOut *oss = (OSSVoiceOut *) hw;
422     int err, decr;
423     struct audio_buf_info abinfo;
424     struct count_info cntinfo;
425     int bufsize;
426 
427     bufsize = hw->samples << hw->info.shift;
428 
429     if (oss->mmapped) {
430         int bytes, pos;
431 
432         err = ioctl (oss->fd, SNDCTL_DSP_GETOPTR, &cntinfo);
433         if (err < 0) {
434             oss_logerr (errno, "SNDCTL_DSP_GETOPTR failed\n");
435             return 0;
436         }
437 
438         pos = hw->rpos << hw->info.shift;
439         bytes = audio_ring_dist (cntinfo.ptr, pos, bufsize);
440         decr = audio_MIN (bytes >> hw->info.shift, live);
441     }
442     else {
443         err = ioctl (oss->fd, SNDCTL_DSP_GETOSPACE, &abinfo);
444         if (err < 0) {
445             oss_logerr (errno, "SNDCTL_DSP_GETOPTR failed\n");
446             return 0;
447         }
448 
449         if (abinfo.bytes > bufsize) {
450             trace_oss_invalid_available_size(abinfo.bytes, bufsize);
451             abinfo.bytes = bufsize;
452         }
453 
454         if (abinfo.bytes < 0) {
455             trace_oss_invalid_available_size(abinfo.bytes, bufsize);
456             return 0;
457         }
458 
459         decr = audio_MIN (abinfo.bytes >> hw->info.shift, live);
460         if (!decr) {
461             return 0;
462         }
463     }
464 
465     decr = audio_pcm_hw_clip_out (hw, oss->pcm_buf, decr, oss->pending);
466     oss->pending += decr;
467     oss_write_pending (oss);
468 
469     return decr;
470 }
471 
472 static void oss_fini_out (HWVoiceOut *hw)
473 {
474     int err;
475     OSSVoiceOut *oss = (OSSVoiceOut *) hw;
476 
477     ldebug ("oss_fini\n");
478     oss_anal_close (&oss->fd);
479 
480     if (oss->pcm_buf) {
481         if (oss->mmapped) {
482             err = munmap (oss->pcm_buf, hw->samples << hw->info.shift);
483             if (err) {
484                 oss_logerr (errno, "Failed to unmap buffer %p, size %d\n",
485                             oss->pcm_buf, hw->samples << hw->info.shift);
486             }
487         }
488         else {
489             g_free (oss->pcm_buf);
490         }
491         oss->pcm_buf = NULL;
492     }
493 }
494 
495 static int oss_init_out(HWVoiceOut *hw, struct audsettings *as,
496                         void *drv_opaque)
497 {
498     OSSVoiceOut *oss = (OSSVoiceOut *) hw;
499     struct oss_params req, obt;
500     int endianness;
501     int err;
502     int fd;
503     audfmt_e effective_fmt;
504     struct audsettings obt_as;
505     OSSConf *conf = drv_opaque;
506 
507     oss->fd = -1;
508 
509     req.fmt = aud_to_ossfmt (as->fmt, as->endianness);
510     req.freq = as->freq;
511     req.nchannels = as->nchannels;
512     req.fragsize = conf->fragsize;
513     req.nfrags = conf->nfrags;
514 
515     if (oss_open (0, &req, &obt, &fd, conf)) {
516         return -1;
517     }
518 
519     err = oss_to_audfmt (obt.fmt, &effective_fmt, &endianness);
520     if (err) {
521         oss_anal_close (&fd);
522         return -1;
523     }
524 
525     obt_as.freq = obt.freq;
526     obt_as.nchannels = obt.nchannels;
527     obt_as.fmt = effective_fmt;
528     obt_as.endianness = endianness;
529 
530     audio_pcm_init_info (&hw->info, &obt_as);
531     oss->nfrags = obt.nfrags;
532     oss->fragsize = obt.fragsize;
533 
534     if (obt.nfrags * obt.fragsize & hw->info.align) {
535         dolog ("warning: Misaligned DAC buffer, size %d, alignment %d\n",
536                obt.nfrags * obt.fragsize, hw->info.align + 1);
537     }
538 
539     hw->samples = (obt.nfrags * obt.fragsize) >> hw->info.shift;
540 
541     oss->mmapped = 0;
542     if (conf->try_mmap) {
543         oss->pcm_buf = mmap (
544             NULL,
545             hw->samples << hw->info.shift,
546             PROT_READ | PROT_WRITE,
547             MAP_SHARED,
548             fd,
549             0
550             );
551         if (oss->pcm_buf == MAP_FAILED) {
552             oss_logerr (errno, "Failed to map %d bytes of DAC\n",
553                         hw->samples << hw->info.shift);
554         }
555         else {
556             int err;
557             int trig = 0;
558             if (ioctl (fd, SNDCTL_DSP_SETTRIGGER, &trig) < 0) {
559                 oss_logerr (errno, "SNDCTL_DSP_SETTRIGGER 0 failed\n");
560             }
561             else {
562                 trig = PCM_ENABLE_OUTPUT;
563                 if (ioctl (fd, SNDCTL_DSP_SETTRIGGER, &trig) < 0) {
564                     oss_logerr (
565                         errno,
566                         "SNDCTL_DSP_SETTRIGGER PCM_ENABLE_OUTPUT failed\n"
567                         );
568                 }
569                 else {
570                     oss->mmapped = 1;
571                 }
572             }
573 
574             if (!oss->mmapped) {
575                 err = munmap (oss->pcm_buf, hw->samples << hw->info.shift);
576                 if (err) {
577                     oss_logerr (errno, "Failed to unmap buffer %p size %d\n",
578                                 oss->pcm_buf, hw->samples << hw->info.shift);
579                 }
580             }
581         }
582     }
583 
584     if (!oss->mmapped) {
585         oss->pcm_buf = audio_calloc (
586             AUDIO_FUNC,
587             hw->samples,
588             1 << hw->info.shift
589             );
590         if (!oss->pcm_buf) {
591             dolog (
592                 "Could not allocate DAC buffer (%d samples, each %d bytes)\n",
593                 hw->samples,
594                 1 << hw->info.shift
595                 );
596             oss_anal_close (&fd);
597             return -1;
598         }
599     }
600 
601     oss->fd = fd;
602     oss->conf = conf;
603     return 0;
604 }
605 
606 static int oss_ctl_out (HWVoiceOut *hw, int cmd, ...)
607 {
608     int trig;
609     OSSVoiceOut *oss = (OSSVoiceOut *) hw;
610 
611     switch (cmd) {
612     case VOICE_ENABLE:
613         {
614             va_list ap;
615             int poll_mode;
616 
617             va_start (ap, cmd);
618             poll_mode = va_arg (ap, int);
619             va_end (ap);
620 
621             ldebug ("enabling voice\n");
622             if (poll_mode) {
623                 oss_poll_out (hw);
624                 poll_mode = 0;
625             }
626             hw->poll_mode = poll_mode;
627 
628             if (!oss->mmapped) {
629                 return 0;
630             }
631 
632             audio_pcm_info_clear_buf (&hw->info, oss->pcm_buf, hw->samples);
633             trig = PCM_ENABLE_OUTPUT;
634             if (ioctl (oss->fd, SNDCTL_DSP_SETTRIGGER, &trig) < 0) {
635                 oss_logerr (
636                     errno,
637                     "SNDCTL_DSP_SETTRIGGER PCM_ENABLE_OUTPUT failed\n"
638                     );
639                 return -1;
640             }
641         }
642         break;
643 
644     case VOICE_DISABLE:
645         if (hw->poll_mode) {
646             qemu_set_fd_handler (oss->fd, NULL, NULL, NULL);
647             hw->poll_mode = 0;
648         }
649 
650         if (!oss->mmapped) {
651             return 0;
652         }
653 
654         ldebug ("disabling voice\n");
655         trig = 0;
656         if (ioctl (oss->fd, SNDCTL_DSP_SETTRIGGER, &trig) < 0) {
657             oss_logerr (errno, "SNDCTL_DSP_SETTRIGGER 0 failed\n");
658             return -1;
659         }
660         break;
661     }
662     return 0;
663 }
664 
665 static int oss_init_in(HWVoiceIn *hw, struct audsettings *as, void *drv_opaque)
666 {
667     OSSVoiceIn *oss = (OSSVoiceIn *) hw;
668     struct oss_params req, obt;
669     int endianness;
670     int err;
671     int fd;
672     audfmt_e effective_fmt;
673     struct audsettings obt_as;
674     OSSConf *conf = drv_opaque;
675 
676     oss->fd = -1;
677 
678     req.fmt = aud_to_ossfmt (as->fmt, as->endianness);
679     req.freq = as->freq;
680     req.nchannels = as->nchannels;
681     req.fragsize = conf->fragsize;
682     req.nfrags = conf->nfrags;
683     if (oss_open (1, &req, &obt, &fd, conf)) {
684         return -1;
685     }
686 
687     err = oss_to_audfmt (obt.fmt, &effective_fmt, &endianness);
688     if (err) {
689         oss_anal_close (&fd);
690         return -1;
691     }
692 
693     obt_as.freq = obt.freq;
694     obt_as.nchannels = obt.nchannels;
695     obt_as.fmt = effective_fmt;
696     obt_as.endianness = endianness;
697 
698     audio_pcm_init_info (&hw->info, &obt_as);
699     oss->nfrags = obt.nfrags;
700     oss->fragsize = obt.fragsize;
701 
702     if (obt.nfrags * obt.fragsize & hw->info.align) {
703         dolog ("warning: Misaligned ADC buffer, size %d, alignment %d\n",
704                obt.nfrags * obt.fragsize, hw->info.align + 1);
705     }
706 
707     hw->samples = (obt.nfrags * obt.fragsize) >> hw->info.shift;
708     oss->pcm_buf = audio_calloc (AUDIO_FUNC, hw->samples, 1 << hw->info.shift);
709     if (!oss->pcm_buf) {
710         dolog ("Could not allocate ADC buffer (%d samples, each %d bytes)\n",
711                hw->samples, 1 << hw->info.shift);
712         oss_anal_close (&fd);
713         return -1;
714     }
715 
716     oss->fd = fd;
717     oss->conf = conf;
718     return 0;
719 }
720 
721 static void oss_fini_in (HWVoiceIn *hw)
722 {
723     OSSVoiceIn *oss = (OSSVoiceIn *) hw;
724 
725     oss_anal_close (&oss->fd);
726 
727     g_free(oss->pcm_buf);
728     oss->pcm_buf = NULL;
729 }
730 
731 static int oss_run_in (HWVoiceIn *hw)
732 {
733     OSSVoiceIn *oss = (OSSVoiceIn *) hw;
734     int hwshift = hw->info.shift;
735     int i;
736     int live = audio_pcm_hw_get_live_in (hw);
737     int dead = hw->samples - live;
738     size_t read_samples = 0;
739     struct {
740         int add;
741         int len;
742     } bufs[2] = {
743         { .add = hw->wpos, .len = 0 },
744         { .add = 0,        .len = 0 }
745     };
746 
747     if (!dead) {
748         return 0;
749     }
750 
751     if (hw->wpos + dead > hw->samples) {
752         bufs[0].len = (hw->samples - hw->wpos) << hwshift;
753         bufs[1].len = (dead - (hw->samples - hw->wpos)) << hwshift;
754     }
755     else {
756         bufs[0].len = dead << hwshift;
757     }
758 
759     for (i = 0; i < 2; ++i) {
760         ssize_t nread;
761 
762         if (bufs[i].len) {
763             void *p = advance (oss->pcm_buf, bufs[i].add << hwshift);
764             nread = read (oss->fd, p, bufs[i].len);
765 
766             if (nread > 0) {
767                 if (nread & hw->info.align) {
768                     dolog ("warning: Misaligned read %zd (requested %d), "
769                            "alignment %d\n", nread, bufs[i].add << hwshift,
770                            hw->info.align + 1);
771                 }
772                 read_samples += nread >> hwshift;
773                 hw->conv (hw->conv_buf + bufs[i].add, p, nread >> hwshift);
774             }
775 
776             if (bufs[i].len - nread) {
777                 if (nread == -1) {
778                     switch (errno) {
779                     case EINTR:
780                     case EAGAIN:
781                         break;
782                     default:
783                         oss_logerr (
784                             errno,
785                             "Failed to read %d bytes of audio (to %p)\n",
786                             bufs[i].len, p
787                             );
788                         break;
789                     }
790                 }
791                 break;
792             }
793         }
794     }
795 
796     hw->wpos = (hw->wpos + read_samples) % hw->samples;
797     return read_samples;
798 }
799 
800 static int oss_read (SWVoiceIn *sw, void *buf, int size)
801 {
802     return audio_pcm_sw_read (sw, buf, size);
803 }
804 
805 static int oss_ctl_in (HWVoiceIn *hw, int cmd, ...)
806 {
807     OSSVoiceIn *oss = (OSSVoiceIn *) hw;
808 
809     switch (cmd) {
810     case VOICE_ENABLE:
811         {
812             va_list ap;
813             int poll_mode;
814 
815             va_start (ap, cmd);
816             poll_mode = va_arg (ap, int);
817             va_end (ap);
818 
819             if (poll_mode) {
820                 oss_poll_in (hw);
821                 poll_mode = 0;
822             }
823             hw->poll_mode = poll_mode;
824         }
825         break;
826 
827     case VOICE_DISABLE:
828         if (hw->poll_mode) {
829             hw->poll_mode = 0;
830             qemu_set_fd_handler (oss->fd, NULL, NULL, NULL);
831         }
832         break;
833     }
834     return 0;
835 }
836 
837 static OSSConf glob_conf = {
838     .try_mmap = 0,
839     .nfrags = 4,
840     .fragsize = 4096,
841     .devpath_out = "/dev/dsp",
842     .devpath_in = "/dev/dsp",
843     .exclusive = 0,
844     .policy = 5
845 };
846 
847 static void *oss_audio_init (void)
848 {
849     OSSConf *conf = g_malloc(sizeof(OSSConf));
850     *conf = glob_conf;
851 
852     if (access(conf->devpath_in, R_OK | W_OK) < 0 ||
853         access(conf->devpath_out, R_OK | W_OK) < 0) {
854         g_free(conf);
855         return NULL;
856     }
857     return conf;
858 }
859 
860 static void oss_audio_fini (void *opaque)
861 {
862     g_free(opaque);
863 }
864 
865 static struct audio_option oss_options[] = {
866     {
867         .name  = "FRAGSIZE",
868         .tag   = AUD_OPT_INT,
869         .valp  = &glob_conf.fragsize,
870         .descr = "Fragment size in bytes"
871     },
872     {
873         .name  = "NFRAGS",
874         .tag   = AUD_OPT_INT,
875         .valp  = &glob_conf.nfrags,
876         .descr = "Number of fragments"
877     },
878     {
879         .name  = "MMAP",
880         .tag   = AUD_OPT_BOOL,
881         .valp  = &glob_conf.try_mmap,
882         .descr = "Try using memory mapped access"
883     },
884     {
885         .name  = "DAC_DEV",
886         .tag   = AUD_OPT_STR,
887         .valp  = &glob_conf.devpath_out,
888         .descr = "Path to DAC device"
889     },
890     {
891         .name  = "ADC_DEV",
892         .tag   = AUD_OPT_STR,
893         .valp  = &glob_conf.devpath_in,
894         .descr = "Path to ADC device"
895     },
896     {
897         .name  = "EXCLUSIVE",
898         .tag   = AUD_OPT_BOOL,
899         .valp  = &glob_conf.exclusive,
900         .descr = "Open device in exclusive mode (vmix won't work)"
901     },
902 #ifdef USE_DSP_POLICY
903     {
904         .name  = "POLICY",
905         .tag   = AUD_OPT_INT,
906         .valp  = &glob_conf.policy,
907         .descr = "Set the timing policy of the device, -1 to use fragment mode",
908     },
909 #endif
910     { /* End of list */ }
911 };
912 
913 static struct audio_pcm_ops oss_pcm_ops = {
914     .init_out = oss_init_out,
915     .fini_out = oss_fini_out,
916     .run_out  = oss_run_out,
917     .write    = oss_write,
918     .ctl_out  = oss_ctl_out,
919 
920     .init_in  = oss_init_in,
921     .fini_in  = oss_fini_in,
922     .run_in   = oss_run_in,
923     .read     = oss_read,
924     .ctl_in   = oss_ctl_in
925 };
926 
927 struct audio_driver oss_audio_driver = {
928     .name           = "oss",
929     .descr          = "OSS http://www.opensound.com",
930     .options        = oss_options,
931     .init           = oss_audio_init,
932     .fini           = oss_audio_fini,
933     .pcm_ops        = &oss_pcm_ops,
934     .can_be_default = 1,
935     .max_voices_out = INT_MAX,
936     .max_voices_in  = INT_MAX,
937     .voice_size_out = sizeof (OSSVoiceOut),
938     .voice_size_in  = sizeof (OSSVoiceIn)
939 };
940