1 /*
2 SDL - Simple DirectMedia Layer
3 Copyright (C) 1997-2006 Sam Lantinga
4
5 This library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 This library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with this library; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18
19 Sam Lantinga
20 slouken@libsdl.org
21 */
22 #include "SDL_config.h"
23
24 /* Allow access to a raw mixing buffer */
25
26 #include <stdio.h>
27 #include <string.h> /* For strerror() */
28 #include <errno.h>
29 #include <unistd.h>
30 #include <fcntl.h>
31 #include <signal.h>
32 #include <sys/types.h>
33 #include <sys/time.h>
34 #include <sys/ioctl.h>
35 #include <sys/stat.h>
36 #include <sys/mman.h>
37
38 #if SDL_AUDIO_DRIVER_OSS_SOUNDCARD_H
39 /* This is installed on some systems */
40 #include <soundcard.h>
41 #else
42 /* This is recommended by OSS */
43 #include <sys/soundcard.h>
44 #endif
45
46 #ifndef MAP_FAILED
47 #define MAP_FAILED ((Uint8 *)-1)
48 #endif
49
50 #include "SDL_timer.h"
51 #include "SDL_audio.h"
52 #include "../SDL_audio_c.h"
53 #include "../SDL_audiodev_c.h"
54 #include "SDL_dmaaudio.h"
55
56 /* The tag name used by DMA audio */
57 #define DMA_DRIVER_NAME "dma"
58
59 /* Open the audio device for playback, and don't block if busy */
60 #define OPEN_FLAGS (O_RDWR|O_NONBLOCK)
61
62 /* Audio driver functions */
63 static int DMA_OpenAudio(_THIS, SDL_AudioSpec *spec);
64 static void DMA_WaitAudio(_THIS);
65 static void DMA_PlayAudio(_THIS);
66 static Uint8 *DMA_GetAudioBuf(_THIS);
67 static void DMA_CloseAudio(_THIS);
68
69 /* Audio driver bootstrap functions */
70
Audio_Available(void)71 static int Audio_Available(void)
72 {
73 int available;
74 int fd;
75
76 available = 0;
77
78 fd = SDL_OpenAudioPath(NULL, 0, OPEN_FLAGS, 0);
79 if ( fd >= 0 ) {
80 int caps;
81 struct audio_buf_info info;
82
83 if ( (ioctl(fd, SNDCTL_DSP_GETCAPS, &caps) == 0) &&
84 (caps & DSP_CAP_TRIGGER) && (caps & DSP_CAP_MMAP) &&
85 (ioctl(fd, SNDCTL_DSP_GETOSPACE, &info) == 0) ) {
86 available = 1;
87 }
88 close(fd);
89 }
90 return(available);
91 }
92
Audio_DeleteDevice(SDL_AudioDevice * device)93 static void Audio_DeleteDevice(SDL_AudioDevice *device)
94 {
95 SDL_free(device->hidden);
96 SDL_free(device);
97 }
98
Audio_CreateDevice(int devindex)99 static SDL_AudioDevice *Audio_CreateDevice(int devindex)
100 {
101 SDL_AudioDevice *this;
102
103 /* Initialize all variables that we clean on shutdown */
104 this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));
105 if ( this ) {
106 SDL_memset(this, 0, (sizeof *this));
107 this->hidden = (struct SDL_PrivateAudioData *)
108 SDL_malloc((sizeof *this->hidden));
109 }
110 if ( (this == NULL) || (this->hidden == NULL) ) {
111 SDL_OutOfMemory();
112 if ( this ) {
113 SDL_free(this);
114 }
115 return(0);
116 }
117 SDL_memset(this->hidden, 0, (sizeof *this->hidden));
118 audio_fd = -1;
119
120 /* Set the function pointers */
121 this->OpenAudio = DMA_OpenAudio;
122 this->WaitAudio = DMA_WaitAudio;
123 this->PlayAudio = DMA_PlayAudio;
124 this->GetAudioBuf = DMA_GetAudioBuf;
125 this->CloseAudio = DMA_CloseAudio;
126
127 this->free = Audio_DeleteDevice;
128
129 return this;
130 }
131
132 AudioBootStrap DMA_bootstrap = {
133 DMA_DRIVER_NAME, "OSS /dev/dsp DMA audio",
134 Audio_Available, Audio_CreateDevice
135 };
136
137 /* This function waits until it is possible to write a full sound buffer */
DMA_WaitAudio(_THIS)138 static void DMA_WaitAudio(_THIS)
139 {
140 fd_set fdset;
141
142 /* Check to see if the thread-parent process is still alive */
143 { static int cnt = 0;
144 /* Note that this only works with thread implementations
145 that use a different process id for each thread.
146 */
147 if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */
148 if ( kill(parent, 0) < 0 ) {
149 this->enabled = 0;
150 }
151 }
152 }
153
154 /* See if we need to use timed audio synchronization */
155 if ( frame_ticks ) {
156 /* Use timer for general audio synchronization */
157 Sint32 ticks;
158
159 ticks = ((Sint32)(next_frame - SDL_GetTicks()))-FUDGE_TICKS;
160 if ( ticks > 0 ) {
161 SDL_Delay(ticks);
162 }
163 } else {
164 /* Use select() for audio synchronization */
165 struct timeval timeout;
166 FD_ZERO(&fdset);
167 FD_SET(audio_fd, &fdset);
168 timeout.tv_sec = 10;
169 timeout.tv_usec = 0;
170 #ifdef DEBUG_AUDIO
171 fprintf(stderr, "Waiting for audio to get ready\n");
172 #endif
173 if ( select(audio_fd+1, NULL, &fdset, NULL, &timeout) <= 0 ) {
174 const char *message =
175 #ifdef AUDIO_OSPACE_HACK
176 "Audio timeout - buggy audio driver? (trying ospace)";
177 #else
178 "Audio timeout - buggy audio driver? (disabled)";
179 #endif
180 /* In general we should never print to the screen,
181 but in this case we have no other way of letting
182 the user know what happened.
183 */
184 fprintf(stderr, "SDL: %s\n", message);
185 #ifdef AUDIO_OSPACE_HACK
186 /* We may be able to use GET_OSPACE trick */
187 frame_ticks = (float)(this->spec->samples*1000) /
188 this->spec->freq;
189 next_frame = SDL_GetTicks()+frame_ticks;
190 #else
191 this->enabled = 0;
192 /* Don't try to close - may hang */
193 audio_fd = -1;
194 #ifdef DEBUG_AUDIO
195 fprintf(stderr, "Done disabling audio\n");
196 #endif
197 #endif /* AUDIO_OSPACE_HACK */
198 }
199 #ifdef DEBUG_AUDIO
200 fprintf(stderr, "Ready!\n");
201 #endif
202 }
203 }
204
DMA_PlayAudio(_THIS)205 static void DMA_PlayAudio(_THIS)
206 {
207 /* If timer synchronization is enabled, set the next write frame */
208 if ( frame_ticks ) {
209 next_frame += frame_ticks;
210 }
211 return;
212 }
213
DMA_GetAudioBuf(_THIS)214 static Uint8 *DMA_GetAudioBuf(_THIS)
215 {
216 count_info info;
217 int playing;
218 int filling;
219
220 /* Get number of blocks, looping if we're not using select() */
221 do {
222 if ( ioctl(audio_fd, SNDCTL_DSP_GETOPTR, &info) < 0 ) {
223 /* Uh oh... */
224 this->enabled = 0;
225 return(NULL);
226 }
227 } while ( frame_ticks && (info.blocks < 1) );
228 #ifdef DEBUG_AUDIO
229 if ( info.blocks > 1 ) {
230 printf("Warning: audio underflow (%d frags)\n", info.blocks-1);
231 }
232 #endif
233 playing = info.ptr / this->spec.size;
234 filling = (playing + 1)%num_buffers;
235 return (dma_buf + (filling * this->spec.size));
236 }
237
DMA_CloseAudio(_THIS)238 static void DMA_CloseAudio(_THIS)
239 {
240 if ( dma_buf != NULL ) {
241 munmap(dma_buf, dma_len);
242 dma_buf = NULL;
243 }
244 if ( audio_fd >= 0 ) {
245 close(audio_fd);
246 audio_fd = -1;
247 }
248 }
249
DMA_ReopenAudio(_THIS,const char * audiodev,int format,int stereo,SDL_AudioSpec * spec)250 static int DMA_ReopenAudio(_THIS, const char *audiodev, int format, int stereo,
251 SDL_AudioSpec *spec)
252 {
253 int frag_spec;
254 int value;
255
256 /* Close and then reopen the audio device */
257 close(audio_fd);
258 audio_fd = open(audiodev, O_RDWR, 0);
259 if ( audio_fd < 0 ) {
260 SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno));
261 return(-1);
262 }
263
264 /* Calculate the final parameters for this audio specification */
265 SDL_CalculateAudioSpec(spec);
266
267 /* Determine the power of two of the fragment size */
268 for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec );
269 if ( (0x01<<frag_spec) != spec->size ) {
270 SDL_SetError("Fragment size must be a power of two");
271 return(-1);
272 }
273
274 /* Set the audio buffering parameters */
275 if ( ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0 ) {
276 SDL_SetError("Couldn't set audio fragment spec");
277 return(-1);
278 }
279
280 /* Set the audio format */
281 value = format;
282 if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
283 (value != format) ) {
284 SDL_SetError("Couldn't set audio format");
285 return(-1);
286 }
287
288 /* Set mono or stereo audio */
289 value = (spec->channels > 1);
290 if ( (ioctl(audio_fd, SNDCTL_DSP_STEREO, &stereo) < 0) ||
291 (value != stereo) ) {
292 SDL_SetError("Couldn't set audio channels");
293 return(-1);
294 }
295
296 /* Set the DSP frequency */
297 value = spec->freq;
298 if ( ioctl(audio_fd, SNDCTL_DSP_SPEED, &value) < 0 ) {
299 SDL_SetError("Couldn't set audio frequency");
300 return(-1);
301 }
302 spec->freq = value;
303
304 /* We successfully re-opened the audio */
305 return(0);
306 }
307
DMA_OpenAudio(_THIS,SDL_AudioSpec * spec)308 static int DMA_OpenAudio(_THIS, SDL_AudioSpec *spec)
309 {
310 char audiodev[1024];
311 int format;
312 int stereo;
313 int value;
314 Uint16 test_format;
315 struct audio_buf_info info;
316
317 /* Reset the timer synchronization flag */
318 frame_ticks = 0.0;
319
320 /* Open the audio device */
321 audio_fd = SDL_OpenAudioPath(audiodev, sizeof(audiodev), OPEN_FLAGS, 0);
322 if ( audio_fd < 0 ) {
323 SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno));
324 return(-1);
325 }
326 dma_buf = NULL;
327 ioctl(audio_fd, SNDCTL_DSP_RESET, 0);
328
329 /* Get a list of supported hardware formats */
330 if ( ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0 ) {
331 SDL_SetError("Couldn't get audio format list");
332 return(-1);
333 }
334
335 /* Try for a closest match on audio format */
336 format = 0;
337 for ( test_format = SDL_FirstAudioFormat(spec->format);
338 ! format && test_format; ) {
339 #ifdef DEBUG_AUDIO
340 fprintf(stderr, "Trying format 0x%4.4x\n", test_format);
341 #endif
342 switch ( test_format ) {
343 case AUDIO_U8:
344 if ( value & AFMT_U8 ) {
345 format = AFMT_U8;
346 }
347 break;
348 case AUDIO_S8:
349 if ( value & AFMT_S8 ) {
350 format = AFMT_S8;
351 }
352 break;
353 case AUDIO_S16LSB:
354 if ( value & AFMT_S16_LE ) {
355 format = AFMT_S16_LE;
356 }
357 break;
358 case AUDIO_S16MSB:
359 if ( value & AFMT_S16_BE ) {
360 format = AFMT_S16_BE;
361 }
362 break;
363 case AUDIO_U16LSB:
364 if ( value & AFMT_U16_LE ) {
365 format = AFMT_U16_LE;
366 }
367 break;
368 case AUDIO_U16MSB:
369 if ( value & AFMT_U16_BE ) {
370 format = AFMT_U16_BE;
371 }
372 break;
373 default:
374 format = 0;
375 break;
376 }
377 if ( ! format ) {
378 test_format = SDL_NextAudioFormat();
379 }
380 }
381 if ( format == 0 ) {
382 SDL_SetError("Couldn't find any hardware audio formats");
383 return(-1);
384 }
385 spec->format = test_format;
386
387 /* Set the audio format */
388 value = format;
389 if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
390 (value != format) ) {
391 SDL_SetError("Couldn't set audio format");
392 return(-1);
393 }
394
395 /* Set mono or stereo audio (currently only two channels supported) */
396 stereo = (spec->channels > 1);
397 ioctl(audio_fd, SNDCTL_DSP_STEREO, &stereo);
398 if ( stereo ) {
399 spec->channels = 2;
400 } else {
401 spec->channels = 1;
402 }
403
404 /* Because some drivers don't allow setting the buffer size
405 after setting the format, we must re-open the audio device
406 once we know what format and channels are supported
407 */
408 if ( DMA_ReopenAudio(this, audiodev, format, stereo, spec) < 0 ) {
409 /* Error is set by DMA_ReopenAudio() */
410 return(-1);
411 }
412
413 /* Memory map the audio buffer */
414 if ( ioctl(audio_fd, SNDCTL_DSP_GETOSPACE, &info) < 0 ) {
415 SDL_SetError("Couldn't get OSPACE parameters");
416 return(-1);
417 }
418 spec->size = info.fragsize;
419 spec->samples = spec->size / ((spec->format & 0xFF) / 8);
420 spec->samples /= spec->channels;
421 num_buffers = info.fragstotal;
422 dma_len = num_buffers*spec->size;
423 dma_buf = (Uint8 *)mmap(NULL, dma_len, PROT_WRITE, MAP_SHARED,
424 audio_fd, 0);
425 if ( dma_buf == MAP_FAILED ) {
426 SDL_SetError("DMA memory map failed");
427 dma_buf = NULL;
428 return(-1);
429 }
430 SDL_memset(dma_buf, spec->silence, dma_len);
431
432 /* Check to see if we need to use select() workaround */
433 { char *workaround;
434 workaround = SDL_getenv("SDL_DSP_NOSELECT");
435 if ( workaround ) {
436 frame_ticks = (float)(spec->samples*1000)/spec->freq;
437 next_frame = SDL_GetTicks()+frame_ticks;
438 }
439 }
440
441 /* Trigger audio playback */
442 value = 0;
443 ioctl(audio_fd, SNDCTL_DSP_SETTRIGGER, &value);
444 value = PCM_ENABLE_OUTPUT;
445 if ( ioctl(audio_fd, SNDCTL_DSP_SETTRIGGER, &value) < 0 ) {
446 SDL_SetError("Couldn't trigger audio output");
447 return(-1);
448 }
449
450 /* Get the parent process id (we're the parent of the audio thread) */
451 parent = getpid();
452
453 /* We're ready to rock and roll. :-) */
454 return(0);
455 }
456