| 1 | /* |
| 2 | SDL - Simple DirectMedia Layer |
| 3 | Copyright (C) 1997-2009 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 | |
| 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 | } |