xref: /qemu/audio/sdlaudio.c (revision b43047a2) 
1 /*
2  * QEMU SDL audio driver
3  *
4  * Copyright (c) 2004-2005 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 <SDL.h>
27 #include <SDL_thread.h>
28 #include "qemu/module.h"
29 #include "audio.h"
30 
31 #ifndef _WIN32
32 #ifdef __sun__
33 #define _POSIX_PTHREAD_SEMANTICS 1
34 #elif defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
35 #include <pthread.h>
36 #endif
37 #endif
38 
39 #define AUDIO_CAP "sdl"
40 #include "audio_int.h"
41 
42 typedef struct SDLVoiceOut {
43     HWVoiceOut hw;
44     size_t live;
45     size_t decr;
46 } SDLVoiceOut;
47 
48 static struct SDLAudioState {
49     int exit;
50     int initialized;
51     bool driver_created;
52     Audiodev *dev;
53 } glob_sdl;
54 typedef struct SDLAudioState SDLAudioState;
55 
56 static void GCC_FMT_ATTR (1, 2) sdl_logerr (const char *fmt, ...)
57 {
58     va_list ap;
59 
60     va_start (ap, fmt);
61     AUD_vlog (AUDIO_CAP, fmt, ap);
62     va_end (ap);
63 
64     AUD_log (AUDIO_CAP, "Reason: %s\n", SDL_GetError ());
65 }
66 
67 static int aud_to_sdlfmt (AudioFormat fmt)
68 {
69     switch (fmt) {
70     case AUDIO_FORMAT_S8:
71         return AUDIO_S8;
72 
73     case AUDIO_FORMAT_U8:
74         return AUDIO_U8;
75 
76     case AUDIO_FORMAT_S16:
77         return AUDIO_S16LSB;
78 
79     case AUDIO_FORMAT_U16:
80         return AUDIO_U16LSB;
81 
82     default:
83         dolog ("Internal logic error: Bad audio format %d\n", fmt);
84 #ifdef DEBUG_AUDIO
85         abort ();
86 #endif
87         return AUDIO_U8;
88     }
89 }
90 
91 static int sdl_to_audfmt(int sdlfmt, AudioFormat *fmt, int *endianness)
92 {
93     switch (sdlfmt) {
94     case AUDIO_S8:
95         *endianness = 0;
96         *fmt = AUDIO_FORMAT_S8;
97         break;
98 
99     case AUDIO_U8:
100         *endianness = 0;
101         *fmt = AUDIO_FORMAT_U8;
102         break;
103 
104     case AUDIO_S16LSB:
105         *endianness = 0;
106         *fmt = AUDIO_FORMAT_S16;
107         break;
108 
109     case AUDIO_U16LSB:
110         *endianness = 0;
111         *fmt = AUDIO_FORMAT_U16;
112         break;
113 
114     case AUDIO_S16MSB:
115         *endianness = 1;
116         *fmt = AUDIO_FORMAT_S16;
117         break;
118 
119     case AUDIO_U16MSB:
120         *endianness = 1;
121         *fmt = AUDIO_FORMAT_U16;
122         break;
123 
124     default:
125         dolog ("Unrecognized SDL audio format %d\n", sdlfmt);
126         return -1;
127     }
128 
129     return 0;
130 }
131 
132 static int sdl_open (SDL_AudioSpec *req, SDL_AudioSpec *obt)
133 {
134     int status;
135 #ifndef _WIN32
136     int err;
137     sigset_t new, old;
138 
139     /* Make sure potential threads created by SDL don't hog signals.  */
140     err = sigfillset (&new);
141     if (err) {
142         dolog ("sdl_open: sigfillset failed: %s\n", strerror (errno));
143         return -1;
144     }
145     err = pthread_sigmask (SIG_BLOCK, &new, &old);
146     if (err) {
147         dolog ("sdl_open: pthread_sigmask failed: %s\n", strerror (err));
148         return -1;
149     }
150 #endif
151 
152     status = SDL_OpenAudio (req, obt);
153     if (status) {
154         sdl_logerr ("SDL_OpenAudio failed\n");
155     }
156 
157 #ifndef _WIN32
158     err = pthread_sigmask (SIG_SETMASK, &old, NULL);
159     if (err) {
160         dolog ("sdl_open: pthread_sigmask (restore) failed: %s\n",
161                strerror (errno));
162         /* We have failed to restore original signal mask, all bets are off,
163            so exit the process */
164         exit (EXIT_FAILURE);
165     }
166 #endif
167     return status;
168 }
169 
170 static void sdl_close (SDLAudioState *s)
171 {
172     if (s->initialized) {
173         SDL_LockAudio();
174         s->exit = 1;
175         SDL_UnlockAudio();
176         SDL_PauseAudio (1);
177         SDL_CloseAudio ();
178         s->initialized = 0;
179     }
180 }
181 
182 static void sdl_callback (void *opaque, Uint8 *buf, int len)
183 {
184     SDLVoiceOut *sdl = opaque;
185     SDLAudioState *s = &glob_sdl;
186     HWVoiceOut *hw = &sdl->hw;
187     size_t samples = len >> hw->info.shift;
188     size_t to_mix, decr;
189 
190     if (s->exit || !sdl->live) {
191         return;
192     }
193 
194     /* dolog ("in callback samples=%zu live=%zu\n", samples, sdl->live); */
195 
196     to_mix = MIN(samples, sdl->live);
197     decr = to_mix;
198     while (to_mix) {
199         size_t chunk = MIN(to_mix, hw->samples - hw->rpos);
200         struct st_sample *src = hw->mix_buf + hw->rpos;
201 
202         /* dolog ("in callback to_mix %zu, chunk %zu\n", to_mix, chunk); */
203         hw->clip(buf, src, chunk);
204         hw->rpos = (hw->rpos + chunk) % hw->samples;
205         to_mix -= chunk;
206         buf += chunk << hw->info.shift;
207     }
208     samples -= decr;
209     sdl->live -= decr;
210     sdl->decr += decr;
211 
212     /* dolog ("done len=%zu\n", len); */
213 
214     /* SDL2 does not clear the remaining buffer for us, so do it on our own */
215     if (samples) {
216         memset(buf, 0, samples << hw->info.shift);
217     }
218 }
219 
220 static size_t sdl_run_out(HWVoiceOut *hw, size_t live)
221 {
222     size_t decr;
223     SDLVoiceOut *sdl = (SDLVoiceOut *) hw;
224 
225     SDL_LockAudio();
226 
227     if (sdl->decr > live) {
228         ldebug ("sdl->decr %d live %d sdl->live %d\n",
229                 sdl->decr,
230                 live,
231                 sdl->live);
232     }
233 
234     decr = MIN (sdl->decr, live);
235     sdl->decr -= decr;
236 
237     sdl->live = live;
238 
239     SDL_UnlockAudio();
240 
241     return decr;
242 }
243 
244 static void sdl_fini_out (HWVoiceOut *hw)
245 {
246     (void) hw;
247 
248     sdl_close (&glob_sdl);
249 }
250 
251 static int sdl_init_out(HWVoiceOut *hw, struct audsettings *as,
252                         void *drv_opaque)
253 {
254     SDLVoiceOut *sdl = (SDLVoiceOut *) hw;
255     SDLAudioState *s = &glob_sdl;
256     SDL_AudioSpec req, obt;
257     int endianness;
258     int err;
259     AudioFormat effective_fmt;
260     struct audsettings obt_as;
261 
262     req.freq = as->freq;
263     req.format = aud_to_sdlfmt (as->fmt);
264     req.channels = as->nchannels;
265     req.samples = audio_buffer_samples(s->dev->u.sdl.out, as, 11610);
266     req.callback = sdl_callback;
267     req.userdata = sdl;
268 
269     if (sdl_open (&req, &obt)) {
270         return -1;
271     }
272 
273     err = sdl_to_audfmt(obt.format, &effective_fmt, &endianness);
274     if (err) {
275         sdl_close (s);
276         return -1;
277     }
278 
279     obt_as.freq = obt.freq;
280     obt_as.nchannels = obt.channels;
281     obt_as.fmt = effective_fmt;
282     obt_as.endianness = endianness;
283 
284     audio_pcm_init_info (&hw->info, &obt_as);
285     hw->samples = obt.samples;
286 
287     s->initialized = 1;
288     s->exit = 0;
289     SDL_PauseAudio (0);
290     return 0;
291 }
292 
293 static int sdl_ctl_out (HWVoiceOut *hw, int cmd, ...)
294 {
295     (void) hw;
296 
297     switch (cmd) {
298     case VOICE_ENABLE:
299         SDL_PauseAudio (0);
300         break;
301 
302     case VOICE_DISABLE:
303         SDL_PauseAudio (1);
304         break;
305     }
306     return 0;
307 }
308 
309 static void *sdl_audio_init(Audiodev *dev)
310 {
311     SDLAudioState *s = &glob_sdl;
312     if (s->driver_created) {
313         sdl_logerr("Can't create multiple sdl backends\n");
314         return NULL;
315     }
316 
317     if (SDL_InitSubSystem (SDL_INIT_AUDIO)) {
318         sdl_logerr ("SDL failed to initialize audio subsystem\n");
319         return NULL;
320     }
321 
322     s->driver_created = true;
323     s->dev = dev;
324     return s;
325 }
326 
327 static void sdl_audio_fini (void *opaque)
328 {
329     SDLAudioState *s = opaque;
330     sdl_close (s);
331     SDL_QuitSubSystem (SDL_INIT_AUDIO);
332     s->driver_created = false;
333     s->dev = NULL;
334 }
335 
336 static struct audio_pcm_ops sdl_pcm_ops = {
337     .init_out = sdl_init_out,
338     .fini_out = sdl_fini_out,
339     .run_out  = sdl_run_out,
340     .ctl_out  = sdl_ctl_out,
341 };
342 
343 static struct audio_driver sdl_audio_driver = {
344     .name           = "sdl",
345     .descr          = "SDL http://www.libsdl.org",
346     .init           = sdl_audio_init,
347     .fini           = sdl_audio_fini,
348     .pcm_ops        = &sdl_pcm_ops,
349     .can_be_default = 1,
350     .max_voices_out = 1,
351     .max_voices_in  = 0,
352     .voice_size_out = sizeof (SDLVoiceOut),
353     .voice_size_in  = 0
354 };
355 
356 static void register_audio_sdl(void)
357 {
358     audio_driver_register(&sdl_audio_driver);
359 }
360 type_init(register_audio_sdl);
361