Mercurial > sdl-ios-xcode
annotate src/audio/dma/SDL_dmaaudio.c @ 524:1b8ea19e9ee4
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| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Tue, 08 Oct 2002 16:29:01 +0000 |
| parents | 30935e76acb5 |
| children | b8d311d90021 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
|
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3 Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga |
| 0 | 4 |
| 5 This library is free software; you can redistribute it and/or | |
| 6 modify it under the terms of the GNU Library General Public | |
| 7 License as published by the Free Software Foundation; either | |
| 8 version 2 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 Library General Public License for more details. | |
| 14 | |
| 15 You should have received a copy of the GNU Library General Public | |
| 16 License along with this library; if not, write to the Free | |
| 17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| 18 | |
| 19 Sam Lantinga | |
|
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20 slouken@libsdl.org |
| 0 | 21 */ |
| 22 | |
| 23 #ifdef SAVE_RCSID | |
| 24 static char rcsid = | |
| 25 "@(#) $Id$"; | |
| 26 #endif | |
| 27 | |
| 28 /* Allow access to a raw mixing buffer */ | |
| 29 | |
| 30 #include <stdlib.h> | |
| 31 #include <stdio.h> | |
| 32 #include <string.h> | |
| 33 #include <errno.h> | |
| 34 #include <unistd.h> | |
| 35 #include <fcntl.h> | |
| 36 #include <signal.h> | |
| 37 #include <sys/types.h> | |
| 38 #include <sys/time.h> | |
| 39 #include <sys/ioctl.h> | |
| 40 #include <sys/stat.h> | |
| 41 #include <sys/mman.h> | |
|
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42 #ifdef OSS_USE_SOUNDCARD_H |
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43 /* This is installed on some systems */ |
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44 #include <soundcard.h> |
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45 #else |
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46 /* This is recommended by OSS */ |
| 0 | 47 #include <sys/soundcard.h> |
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48 #endif |
| 0 | 49 |
| 50 #ifndef MAP_FAILED | |
| 51 #define MAP_FAILED ((Uint8 *)-1) | |
| 52 #endif | |
| 53 | |
| 54 #include "SDL_audio.h" | |
| 55 #include "SDL_error.h" | |
| 56 #include "SDL_audiomem.h" | |
| 57 #include "SDL_audio_c.h" | |
| 58 #include "SDL_timer.h" | |
| 59 #include "SDL_audiodev_c.h" | |
| 60 #include "SDL_dmaaudio.h" | |
| 61 | |
| 62 /* The tag name used by DMA audio */ | |
| 63 #define DMA_DRIVER_NAME "dma" | |
| 64 | |
| 65 /* Open the audio device for playback, and don't block if busy */ | |
| 66 #define OPEN_FLAGS (O_RDWR|O_NONBLOCK) | |
| 67 | |
| 68 /* Audio driver functions */ | |
| 69 static int DMA_OpenAudio(_THIS, SDL_AudioSpec *spec); | |
| 70 static void DMA_WaitAudio(_THIS); | |
| 71 static void DMA_PlayAudio(_THIS); | |
| 72 static Uint8 *DMA_GetAudioBuf(_THIS); | |
| 73 static void DMA_CloseAudio(_THIS); | |
| 74 | |
| 75 /* Audio driver bootstrap functions */ | |
| 76 | |
| 77 static int Audio_Available(void) | |
| 78 { | |
| 79 int available; | |
| 80 int fd; | |
| 81 | |
| 82 available = 0; | |
| 83 | |
| 84 fd = SDL_OpenAudioPath(NULL, 0, OPEN_FLAGS, 0); | |
| 85 if ( fd >= 0 ) { | |
| 86 int caps; | |
| 87 struct audio_buf_info info; | |
| 88 | |
| 89 if ( (ioctl(fd, SNDCTL_DSP_GETCAPS, &caps) == 0) && | |
| 90 (caps & DSP_CAP_TRIGGER) && (caps & DSP_CAP_MMAP) && | |
| 91 (ioctl(fd, SNDCTL_DSP_GETOSPACE, &info) == 0) ) { | |
| 92 available = 1; | |
| 93 } | |
| 94 close(fd); | |
| 95 } | |
| 96 return(available); | |
| 97 } | |
| 98 | |
| 99 static void Audio_DeleteDevice(SDL_AudioDevice *device) | |
| 100 { | |
| 101 free(device->hidden); | |
| 102 free(device); | |
| 103 } | |
| 104 | |
| 105 static SDL_AudioDevice *Audio_CreateDevice(int devindex) | |
| 106 { | |
| 107 SDL_AudioDevice *this; | |
| 108 | |
| 109 /* Initialize all variables that we clean on shutdown */ | |
| 110 this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice)); | |
| 111 if ( this ) { | |
| 112 memset(this, 0, (sizeof *this)); | |
| 113 this->hidden = (struct SDL_PrivateAudioData *) | |
| 114 malloc((sizeof *this->hidden)); | |
| 115 } | |
| 116 if ( (this == NULL) || (this->hidden == NULL) ) { | |
| 117 SDL_OutOfMemory(); | |
| 118 if ( this ) { | |
| 119 free(this); | |
| 120 } | |
| 121 return(0); | |
| 122 } | |
| 123 memset(this->hidden, 0, (sizeof *this->hidden)); | |
| 124 audio_fd = -1; | |
| 125 | |
| 126 /* Set the function pointers */ | |
| 127 this->OpenAudio = DMA_OpenAudio; | |
| 128 this->WaitAudio = DMA_WaitAudio; | |
| 129 this->PlayAudio = DMA_PlayAudio; | |
| 130 this->GetAudioBuf = DMA_GetAudioBuf; | |
| 131 this->CloseAudio = DMA_CloseAudio; | |
| 132 | |
| 133 this->free = Audio_DeleteDevice; | |
| 134 | |
| 135 return this; | |
| 136 } | |
| 137 | |
| 138 AudioBootStrap DMA_bootstrap = { | |
| 139 DMA_DRIVER_NAME, "OSS /dev/dsp DMA audio", | |
| 140 Audio_Available, Audio_CreateDevice | |
| 141 }; | |
| 142 | |
| 143 /* This function waits until it is possible to write a full sound buffer */ | |
| 144 static void DMA_WaitAudio(_THIS) | |
| 145 { | |
| 146 fd_set fdset; | |
| 147 | |
| 148 /* Check to see if the thread-parent process is still alive */ | |
| 149 { static int cnt = 0; | |
| 150 /* Note that this only works with thread implementations | |
| 151 that use a different process id for each thread. | |
| 152 */ | |
| 153 if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */ | |
| 154 if ( kill(parent, 0) < 0 ) { | |
| 155 this->enabled = 0; | |
| 156 } | |
| 157 } | |
| 158 } | |
| 159 | |
| 160 /* See if we need to use timed audio synchronization */ | |
| 161 if ( frame_ticks ) { | |
| 162 /* Use timer for general audio synchronization */ | |
| 163 Sint32 ticks; | |
| 164 | |
| 165 ticks = ((Sint32)(next_frame - SDL_GetTicks()))-FUDGE_TICKS; | |
| 166 if ( ticks > 0 ) { | |
| 167 SDL_Delay(ticks); | |
| 168 } | |
| 169 } else { | |
| 170 /* Use select() for audio synchronization */ | |
| 171 struct timeval timeout; | |
| 172 FD_ZERO(&fdset); | |
| 173 FD_SET(audio_fd, &fdset); | |
| 174 timeout.tv_sec = 10; | |
| 175 timeout.tv_usec = 0; | |
| 176 #ifdef DEBUG_AUDIO | |
| 177 fprintf(stderr, "Waiting for audio to get ready\n"); | |
| 178 #endif | |
| 179 if ( select(audio_fd+1, NULL, &fdset, NULL, &timeout) <= 0 ) { | |
| 180 const char *message = | |
| 181 #ifdef AUDIO_OSPACE_HACK | |
| 182 "Audio timeout - buggy audio driver? (trying ospace)"; | |
| 183 #else | |
| 184 "Audio timeout - buggy audio driver? (disabled)"; | |
| 185 #endif | |
| 186 /* In general we should never print to the screen, | |
| 187 but in this case we have no other way of letting | |
| 188 the user know what happened. | |
| 189 */ | |
| 190 fprintf(stderr, "SDL: %s\n", message); | |
| 191 #ifdef AUDIO_OSPACE_HACK | |
| 192 /* We may be able to use GET_OSPACE trick */ | |
| 193 frame_ticks = (float)(this->spec->samples*1000) / | |
| 194 this->spec->freq; | |
| 195 next_frame = SDL_GetTicks()+frame_ticks; | |
| 196 #else | |
| 197 this->enabled = 0; | |
| 198 /* Don't try to close - may hang */ | |
| 199 audio_fd = -1; | |
| 200 #ifdef DEBUG_AUDIO | |
| 201 fprintf(stderr, "Done disabling audio\n"); | |
| 202 #endif | |
| 203 #endif /* AUDIO_OSPACE_HACK */ | |
| 204 } | |
| 205 #ifdef DEBUG_AUDIO | |
| 206 fprintf(stderr, "Ready!\n"); | |
| 207 #endif | |
| 208 } | |
| 209 } | |
| 210 | |
| 211 static void DMA_PlayAudio(_THIS) | |
| 212 { | |
| 213 /* If timer synchronization is enabled, set the next write frame */ | |
| 214 if ( frame_ticks ) { | |
| 215 next_frame += frame_ticks; | |
| 216 } | |
| 217 return; | |
| 218 } | |
| 219 | |
| 220 static Uint8 *DMA_GetAudioBuf(_THIS) | |
| 221 { | |
| 222 count_info info; | |
| 223 int playing; | |
| 224 int filling; | |
| 225 | |
| 226 /* Get number of blocks, looping if we're not using select() */ | |
| 227 do { | |
| 228 if ( ioctl(audio_fd, SNDCTL_DSP_GETOPTR, &info) < 0 ) { | |
| 229 /* Uh oh... */ | |
| 230 this->enabled = 0; | |
| 231 return(NULL); | |
| 232 } | |
| 233 } while ( frame_ticks && (info.blocks < 1) ); | |
| 234 #ifdef DEBUG_AUDIO | |
| 235 if ( info.blocks > 1 ) { | |
| 236 printf("Warning: audio underflow (%d frags)\n", info.blocks-1); | |
| 237 } | |
| 238 #endif | |
| 239 playing = info.ptr / this->spec.size; | |
| 240 filling = (playing + 1)%num_buffers; | |
| 241 return (dma_buf + (filling * this->spec.size)); | |
| 242 } | |
| 243 | |
| 244 static void DMA_CloseAudio(_THIS) | |
| 245 { | |
| 246 if ( dma_buf != NULL ) { | |
| 247 munmap(dma_buf, dma_len); | |
| 248 dma_buf = NULL; | |
| 249 } | |
| 250 if ( audio_fd >= 0 ) { | |
| 251 close(audio_fd); | |
| 252 audio_fd = -1; | |
| 253 } | |
| 254 } | |
| 255 | |
| 256 static int DMA_ReopenAudio(_THIS, const char *audiodev, int format, int stereo, | |
| 257 SDL_AudioSpec *spec) | |
| 258 { | |
| 259 int frag_spec; | |
| 260 int value; | |
| 261 | |
| 262 /* Close and then reopen the audio device */ | |
| 263 close(audio_fd); | |
| 264 audio_fd = open(audiodev, O_RDWR, 0); | |
| 265 if ( audio_fd < 0 ) { | |
| 266 SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno)); | |
| 267 return(-1); | |
| 268 } | |
| 269 | |
| 270 /* Calculate the final parameters for this audio specification */ | |
| 271 SDL_CalculateAudioSpec(spec); | |
| 272 | |
| 273 /* Determine the power of two of the fragment size */ | |
| 274 for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec ); | |
| 275 if ( (0x01<<frag_spec) != spec->size ) { | |
| 276 SDL_SetError("Fragment size must be a power of two"); | |
| 277 return(-1); | |
| 278 } | |
| 279 | |
| 280 /* Set the audio buffering parameters */ | |
| 281 if ( ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0 ) { | |
| 282 SDL_SetError("Couldn't set audio fragment spec"); | |
| 283 return(-1); | |
| 284 } | |
| 285 | |
| 286 /* Set the audio format */ | |
| 287 value = format; | |
| 288 if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) || | |
| 289 (value != format) ) { | |
| 290 SDL_SetError("Couldn't set audio format"); | |
| 291 return(-1); | |
| 292 } | |
| 293 | |
| 294 /* Set mono or stereo audio */ | |
| 295 value = (spec->channels > 1); | |
| 296 if ( (ioctl(audio_fd, SNDCTL_DSP_STEREO, &stereo) < 0) || | |
| 297 (value != stereo) ) { | |
| 298 SDL_SetError("Couldn't set audio channels"); | |
| 299 return(-1); | |
| 300 } | |
| 301 | |
| 302 /* Set the DSP frequency */ | |
| 303 value = spec->freq; | |
| 304 if ( ioctl(audio_fd, SOUND_PCM_WRITE_RATE, &value) < 0 ) { | |
| 305 SDL_SetError("Couldn't set audio frequency"); | |
| 306 return(-1); | |
| 307 } | |
| 308 spec->freq = value; | |
| 309 | |
| 310 /* We successfully re-opened the audio */ | |
| 311 return(0); | |
| 312 } | |
| 313 | |
| 314 static int DMA_OpenAudio(_THIS, SDL_AudioSpec *spec) | |
| 315 { | |
| 316 char audiodev[1024]; | |
| 317 int format; | |
| 318 int stereo; | |
| 319 int value; | |
| 320 Uint16 test_format; | |
| 321 struct audio_buf_info info; | |
| 322 | |
| 323 /* Reset the timer synchronization flag */ | |
| 324 frame_ticks = 0.0; | |
| 325 | |
| 326 /* Open the audio device */ | |
| 327 audio_fd = SDL_OpenAudioPath(audiodev, sizeof(audiodev), OPEN_FLAGS, 0); | |
| 328 if ( audio_fd < 0 ) { | |
| 329 SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno)); | |
| 330 return(-1); | |
| 331 } | |
| 332 dma_buf = NULL; | |
| 333 ioctl(audio_fd, SNDCTL_DSP_RESET, 0); | |
| 334 | |
| 335 /* Get a list of supported hardware formats */ | |
| 336 if ( ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0 ) { | |
| 337 SDL_SetError("Couldn't get audio format list"); | |
| 338 return(-1); | |
| 339 } | |
| 340 | |
| 341 /* Try for a closest match on audio format */ | |
| 342 format = 0; | |
| 343 for ( test_format = SDL_FirstAudioFormat(spec->format); | |
| 344 ! format && test_format; ) { | |
| 345 #ifdef DEBUG_AUDIO | |
| 346 fprintf(stderr, "Trying format 0x%4.4x\n", test_format); | |
| 347 #endif | |
| 348 switch ( test_format ) { | |
| 349 case AUDIO_U8: | |
| 350 if ( value & AFMT_U8 ) { | |
| 351 format = AFMT_U8; | |
| 352 } | |
| 353 break; | |
| 354 case AUDIO_S8: | |
| 355 if ( value & AFMT_S8 ) { | |
| 356 format = AFMT_S8; | |
| 357 } | |
| 358 break; | |
| 359 case AUDIO_S16LSB: | |
| 360 if ( value & AFMT_S16_LE ) { | |
| 361 format = AFMT_S16_LE; | |
| 362 } | |
| 363 break; | |
| 364 case AUDIO_S16MSB: | |
| 365 if ( value & AFMT_S16_BE ) { | |
| 366 format = AFMT_S16_BE; | |
| 367 } | |
| 368 break; | |
| 369 case AUDIO_U16LSB: | |
| 370 if ( value & AFMT_U16_LE ) { | |
| 371 format = AFMT_U16_LE; | |
| 372 } | |
| 373 break; | |
| 374 case AUDIO_U16MSB: | |
| 375 if ( value & AFMT_U16_BE ) { | |
| 376 format = AFMT_U16_BE; | |
| 377 } | |
| 378 break; | |
| 379 default: | |
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380 format = 0; |
| 0 | 381 break; |
| 382 } | |
| 383 if ( ! format ) { | |
| 384 test_format = SDL_NextAudioFormat(); | |
| 385 } | |
| 386 } | |
| 387 if ( format == 0 ) { | |
| 388 SDL_SetError("Couldn't find any hardware audio formats"); | |
| 389 return(-1); | |
| 390 } | |
| 391 spec->format = test_format; | |
| 392 | |
| 393 /* Set the audio format */ | |
| 394 value = format; | |
| 395 if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) || | |
| 396 (value != format) ) { | |
| 397 SDL_SetError("Couldn't set audio format"); | |
| 398 return(-1); | |
| 399 } | |
| 400 | |
| 401 /* Set mono or stereo audio (currently only two channels supported) */ | |
| 402 stereo = (spec->channels > 1); | |
| 403 ioctl(audio_fd, SNDCTL_DSP_STEREO, &stereo); | |
| 404 if ( stereo ) { | |
| 405 spec->channels = 2; | |
| 406 } else { | |
| 407 spec->channels = 1; | |
| 408 } | |
| 409 | |
| 410 /* Because some drivers don't allow setting the buffer size | |
| 411 after setting the format, we must re-open the audio device | |
| 412 once we know what format and channels are supported | |
| 413 */ | |
| 414 if ( DMA_ReopenAudio(this, audiodev, format, stereo, spec) < 0 ) { | |
| 415 /* Error is set by DMA_ReopenAudio() */ | |
| 416 return(-1); | |
| 417 } | |
| 418 | |
| 419 /* Memory map the audio buffer */ | |
| 420 if ( ioctl(audio_fd, SNDCTL_DSP_GETOSPACE, &info) < 0 ) { | |
| 421 SDL_SetError("Couldn't get OSPACE parameters"); | |
| 422 return(-1); | |
| 423 } | |
| 424 spec->size = info.fragsize; | |
| 425 spec->samples = spec->size / ((spec->format & 0xFF) / 8); | |
| 426 spec->samples /= spec->channels; | |
| 427 num_buffers = info.fragstotal; | |
| 428 dma_len = num_buffers*spec->size; | |
| 429 dma_buf = (Uint8 *)mmap(NULL, dma_len, PROT_WRITE, MAP_SHARED, | |
| 430 audio_fd, 0); | |
| 431 if ( dma_buf == MAP_FAILED ) { | |
| 432 SDL_SetError("DMA memory map failed"); | |
| 433 dma_buf = NULL; | |
| 434 return(-1); | |
| 435 } | |
| 436 memset(dma_buf, spec->silence, dma_len); | |
| 437 | |
| 438 /* Check to see if we need to use select() workaround */ | |
| 439 { char *workaround; | |
| 440 workaround = getenv("SDL_DSP_NOSELECT"); | |
| 441 if ( workaround ) { | |
| 442 frame_ticks = (float)(spec->samples*1000)/spec->freq; | |
| 443 next_frame = SDL_GetTicks()+frame_ticks; | |
| 444 } | |
| 445 } | |
| 446 | |
| 447 /* Trigger audio playback */ | |
| 448 value = 0; | |
| 449 ioctl(audio_fd, SNDCTL_DSP_SETTRIGGER, &value); | |
| 450 value = PCM_ENABLE_OUTPUT; | |
| 451 if ( ioctl(audio_fd, SNDCTL_DSP_SETTRIGGER, &value) < 0 ) { | |
| 452 SDL_SetError("Couldn't trigger audio output"); | |
| 453 return(-1); | |
| 454 } | |
| 455 | |
| 456 /* Get the parent process id (we're the parent of the audio thread) */ | |
| 457 parent = getpid(); | |
| 458 | |
| 459 /* We're ready to rock and roll. :-) */ | |
| 460 return(0); | |
| 461 } |