1 /* 2 SDL - Simple DirectMedia Layer 3 Copyright (C) 1997-2012 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 (at) 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 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 93 static void Audio_DeleteDevice(SDL_AudioDevice *device) 94 { 95 SDL_free(device->hidden); 96 SDL_free(device); 97 } 98 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 */ 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 } 204 205 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 } 213 214 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 } 237 238 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 } 249 250 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 } 307 308 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
