| 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 | Modified in Oct 2004 by Hannu Savolainen |
| 23 | hannu@opensound.com |
| 24 | */ |
| 25 | #include "SDL_config.h" |
| 26 | |
| 27 | /* Allow access to a raw mixing buffer */ |
| 28 | |
| 29 | #include <stdio.h> /* For perror() */ |
| 30 | #include <string.h> /* For strerror() */ |
| 31 | #include <errno.h> |
| 32 | #include <unistd.h> |
| 33 | #include <fcntl.h> |
| 34 | #include <signal.h> |
| 35 | #include <sys/time.h> |
| 36 | #include <sys/ioctl.h> |
| 37 | #include <sys/stat.h> |
| 38 | |
| 39 | #if SDL_AUDIO_DRIVER_OSS_SOUNDCARD_H |
| 40 | /* This is installed on some systems */ |
| 41 | #include <soundcard.h> |
| 42 | #else |
| 43 | /* This is recommended by OSS */ |
| 44 | #include <sys/soundcard.h> |
| 45 | #endif |
| 46 | |
| 47 | #include "SDL_timer.h" |
| 48 | #include "SDL_audio.h" |
| 49 | #include "../SDL_audiomem.h" |
| 50 | #include "../SDL_audio_c.h" |
| 51 | #include "../SDL_audiodev_c.h" |
| 52 | #include "SDL_dspaudio.h" |
| 53 | |
| 54 | /* The tag name used by DSP audio */ |
| 55 | #define DSP_DRIVER_NAME "dsp" |
| 56 | |
| 57 | /* Open the audio device for playback, and don't block if busy */ |
| 58 | #define OPEN_FLAGS (O_WRONLY|O_NONBLOCK) |
| 59 | |
| 60 | /* Audio driver functions */ |
| 61 | static int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec); |
| 62 | static void DSP_WaitAudio(_THIS); |
| 63 | static void DSP_PlayAudio(_THIS); |
| 64 | static Uint8 *DSP_GetAudioBuf(_THIS); |
| 65 | static void DSP_CloseAudio(_THIS); |
| 66 | |
| 67 | /* Audio driver bootstrap functions */ |
| 68 | |
| 69 | static int Audio_Available(void) |
| 70 | { |
| 71 | int fd; |
| 72 | int available; |
| 73 | |
| 74 | available = 0; |
| 75 | fd = SDL_OpenAudioPath(NULL, 0, OPEN_FLAGS, 0); |
| 76 | if ( fd >= 0 ) { |
| 77 | available = 1; |
| 78 | close(fd); |
| 79 | } |
| 80 | return(available); |
| 81 | } |
| 82 | |
| 83 | static void Audio_DeleteDevice(SDL_AudioDevice *device) |
| 84 | { |
| 85 | SDL_free(device->hidden); |
| 86 | SDL_free(device); |
| 87 | } |
| 88 | |
| 89 | static SDL_AudioDevice *Audio_CreateDevice(int devindex) |
| 90 | { |
| 91 | SDL_AudioDevice *this; |
| 92 | |
| 93 | /* Initialize all variables that we clean on shutdown */ |
| 94 | this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice)); |
| 95 | if ( this ) { |
| 96 | SDL_memset(this, 0, (sizeof *this)); |
| 97 | this->hidden = (struct SDL_PrivateAudioData *) |
| 98 | SDL_malloc((sizeof *this->hidden)); |
| 99 | } |
| 100 | if ( (this == NULL) || (this->hidden == NULL) ) { |
| 101 | SDL_OutOfMemory(); |
| 102 | if ( this ) { |
| 103 | SDL_free(this); |
| 104 | } |
| 105 | return(0); |
| 106 | } |
| 107 | SDL_memset(this->hidden, 0, (sizeof *this->hidden)); |
| 108 | audio_fd = -1; |
| 109 | |
| 110 | /* Set the function pointers */ |
| 111 | this->OpenAudio = DSP_OpenAudio; |
| 112 | this->WaitAudio = DSP_WaitAudio; |
| 113 | this->PlayAudio = DSP_PlayAudio; |
| 114 | this->GetAudioBuf = DSP_GetAudioBuf; |
| 115 | this->CloseAudio = DSP_CloseAudio; |
| 116 | |
| 117 | this->free = Audio_DeleteDevice; |
| 118 | |
| 119 | return this; |
| 120 | } |
| 121 | |
| 122 | AudioBootStrap DSP_bootstrap = { |
| 123 | DSP_DRIVER_NAME, "OSS /dev/dsp standard audio", |
| 124 | Audio_Available, Audio_CreateDevice |
| 125 | }; |
| 126 | |
| 127 | /* This function waits until it is possible to write a full sound buffer */ |
| 128 | static void DSP_WaitAudio(_THIS) |
| 129 | { |
| 130 | /* Not needed at all since OSS handles waiting automagically */ |
| 131 | } |
| 132 | |
| 133 | static void DSP_PlayAudio(_THIS) |
| 134 | { |
| 135 | if (write(audio_fd, mixbuf, mixlen)==-1) |
| 136 | { |
| 137 | perror("Audio write"); |
| 138 | this->enabled = 0; |
| 139 | } |
| 140 | |
| 141 | #ifdef DEBUG_AUDIO |
| 142 | fprintf(stderr, "Wrote %d bytes of audio data\n", mixlen); |
| 143 | #endif |
| 144 | } |
| 145 | |
| 146 | static Uint8 *DSP_GetAudioBuf(_THIS) |
| 147 | { |
| 148 | return(mixbuf); |
| 149 | } |
| 150 | |
| 151 | static void DSP_CloseAudio(_THIS) |
| 152 | { |
| 153 | if ( mixbuf != NULL ) { |
| 154 | SDL_FreeAudioMem(mixbuf); |
| 155 | mixbuf = NULL; |
| 156 | } |
| 157 | if ( audio_fd >= 0 ) { |
| 158 | close(audio_fd); |
| 159 | audio_fd = -1; |
| 160 | } |
| 161 | } |
| 162 | |
| 163 | static int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec) |
| 164 | { |
| 165 | char audiodev[1024]; |
| 166 | int format; |
| 167 | int value; |
| 168 | int frag_spec; |
| 169 | Uint16 test_format; |
| 170 | |
| 171 | /* Make sure fragment size stays a power of 2, or OSS fails. */ |
| 172 | /* I don't know which of these are actually legal values, though... */ |
| 173 | if (spec->channels > 8) |
| 174 | spec->channels = 8; |
| 175 | else if (spec->channels > 4) |
| 176 | spec->channels = 4; |
| 177 | else if (spec->channels > 2) |
| 178 | spec->channels = 2; |
| 179 | |
| 180 | /* Open the audio device */ |
| 181 | audio_fd = SDL_OpenAudioPath(audiodev, sizeof(audiodev), OPEN_FLAGS, 0); |
| 182 | if ( audio_fd < 0 ) { |
| 183 | SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno)); |
| 184 | return(-1); |
| 185 | } |
| 186 | mixbuf = NULL; |
| 187 | |
| 188 | /* Make the file descriptor use blocking writes with fcntl() */ |
| 189 | { long flags; |
| 190 | flags = fcntl(audio_fd, F_GETFL); |
| 191 | flags &= ~O_NONBLOCK; |
| 192 | if ( fcntl(audio_fd, F_SETFL, flags) < 0 ) { |
| 193 | SDL_SetError("Couldn't set audio blocking mode"); |
| 194 | DSP_CloseAudio(this); |
| 195 | return(-1); |
| 196 | } |
| 197 | } |
| 198 | |
| 199 | /* Get a list of supported hardware formats */ |
| 200 | if ( ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0 ) { |
| 201 | perror("SNDCTL_DSP_GETFMTS"); |
| 202 | SDL_SetError("Couldn't get audio format list"); |
| 203 | DSP_CloseAudio(this); |
| 204 | return(-1); |
| 205 | } |
| 206 | |
| 207 | /* Try for a closest match on audio format */ |
| 208 | format = 0; |
| 209 | for ( test_format = SDL_FirstAudioFormat(spec->format); |
| 210 | ! format && test_format; ) { |
| 211 | #ifdef DEBUG_AUDIO |
| 212 | fprintf(stderr, "Trying format 0x%4.4x\n", test_format); |
| 213 | #endif |
| 214 | switch ( test_format ) { |
| 215 | case AUDIO_U8: |
| 216 | if ( value & AFMT_U8 ) { |
| 217 | format = AFMT_U8; |
| 218 | } |
| 219 | break; |
| 220 | case AUDIO_S16LSB: |
| 221 | if ( value & AFMT_S16_LE ) { |
| 222 | format = AFMT_S16_LE; |
| 223 | } |
| 224 | break; |
| 225 | case AUDIO_S16MSB: |
| 226 | if ( value & AFMT_S16_BE ) { |
| 227 | format = AFMT_S16_BE; |
| 228 | } |
| 229 | break; |
| 230 | #if 0 |
| 231 | /* |
| 232 | * These formats are not used by any real life systems so they are not |
| 233 | * needed here. |
| 234 | */ |
| 235 | case AUDIO_S8: |
| 236 | if ( value & AFMT_S8 ) { |
| 237 | format = AFMT_S8; |
| 238 | } |
| 239 | break; |
| 240 | case AUDIO_U16LSB: |
| 241 | if ( value & AFMT_U16_LE ) { |
| 242 | format = AFMT_U16_LE; |
| 243 | } |
| 244 | break; |
| 245 | case AUDIO_U16MSB: |
| 246 | if ( value & AFMT_U16_BE ) { |
| 247 | format = AFMT_U16_BE; |
| 248 | } |
| 249 | break; |
| 250 | #endif |
| 251 | default: |
| 252 | format = 0; |
| 253 | break; |
| 254 | } |
| 255 | if ( ! format ) { |
| 256 | test_format = SDL_NextAudioFormat(); |
| 257 | } |
| 258 | } |
| 259 | if ( format == 0 ) { |
| 260 | SDL_SetError("Couldn't find any hardware audio formats"); |
| 261 | DSP_CloseAudio(this); |
| 262 | return(-1); |
| 263 | } |
| 264 | spec->format = test_format; |
| 265 | |
| 266 | /* Set the audio format */ |
| 267 | value = format; |
| 268 | if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) || |
| 269 | (value != format) ) { |
| 270 | perror("SNDCTL_DSP_SETFMT"); |
| 271 | SDL_SetError("Couldn't set audio format"); |
| 272 | DSP_CloseAudio(this); |
| 273 | return(-1); |
| 274 | } |
| 275 | |
| 276 | /* Set the number of channels of output */ |
| 277 | value = spec->channels; |
| 278 | if ( ioctl(audio_fd, SNDCTL_DSP_CHANNELS, &value) < 0 ) { |
| 279 | perror("SNDCTL_DSP_CHANNELS"); |
| 280 | SDL_SetError("Cannot set the number of channels"); |
| 281 | DSP_CloseAudio(this); |
| 282 | return(-1); |
| 283 | } |
| 284 | spec->channels = value; |
| 285 | |
| 286 | /* Set the DSP frequency */ |
| 287 | value = spec->freq; |
| 288 | if ( ioctl(audio_fd, SNDCTL_DSP_SPEED, &value) < 0 ) { |
| 289 | perror("SNDCTL_DSP_SPEED"); |
| 290 | SDL_SetError("Couldn't set audio frequency"); |
| 291 | DSP_CloseAudio(this); |
| 292 | return(-1); |
| 293 | } |
| 294 | spec->freq = value; |
| 295 | |
| 296 | /* Calculate the final parameters for this audio specification */ |
| 297 | SDL_CalculateAudioSpec(spec); |
| 298 | |
| 299 | /* Determine the power of two of the fragment size */ |
| 300 | for ( frag_spec = 0; (0x01U<<frag_spec) < spec->size; ++frag_spec ); |
| 301 | if ( (0x01U<<frag_spec) != spec->size ) { |
| 302 | SDL_SetError("Fragment size must be a power of two"); |
| 303 | DSP_CloseAudio(this); |
| 304 | return(-1); |
| 305 | } |
| 306 | frag_spec |= 0x00020000; /* two fragments, for low latency */ |
| 307 | |
| 308 | /* Set the audio buffering parameters */ |
| 309 | #ifdef DEBUG_AUDIO |
| 310 | fprintf(stderr, "Requesting %d fragments of size %d\n", |
| 311 | (frag_spec >> 16), 1<<(frag_spec&0xFFFF)); |
| 312 | #endif |
| 313 | if ( ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0 ) { |
| 314 | perror("SNDCTL_DSP_SETFRAGMENT"); |
| 315 | } |
| 316 | #ifdef DEBUG_AUDIO |
| 317 | { audio_buf_info info; |
| 318 | ioctl(audio_fd, SNDCTL_DSP_GETOSPACE, &info); |
| 319 | fprintf(stderr, "fragments = %d\n", info.fragments); |
| 320 | fprintf(stderr, "fragstotal = %d\n", info.fragstotal); |
| 321 | fprintf(stderr, "fragsize = %d\n", info.fragsize); |
| 322 | fprintf(stderr, "bytes = %d\n", info.bytes); |
| 323 | } |
| 324 | #endif |
| 325 | |
| 326 | /* Allocate mixing buffer */ |
| 327 | mixlen = spec->size; |
| 328 | mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen); |
| 329 | if ( mixbuf == NULL ) { |
| 330 | DSP_CloseAudio(this); |
| 331 | return(-1); |
| 332 | } |
| 333 | SDL_memset(mixbuf, spec->silence, spec->size); |
| 334 | |
| 335 | /* Get the parent process id (we're the parent of the audio thread) */ |
| 336 | parent = getpid(); |
| 337 | |
| 338 | /* We're ready to rock and roll. :-) */ |
| 339 | return(0); |
| 340 | } |