diff options
Diffstat (limited to 'distrib/sdl-1.2.15/src/audio/dma/SDL_dmaaudio.c')
| -rw-r--r-- | distrib/sdl-1.2.15/src/audio/dma/SDL_dmaaudio.c | 455 |
1 files changed, 455 insertions, 0 deletions
diff --git a/distrib/sdl-1.2.15/src/audio/dma/SDL_dmaaudio.c b/distrib/sdl-1.2.15/src/audio/dma/SDL_dmaaudio.c new file mode 100644 index 0000000..39f81d9 --- /dev/null +++ b/distrib/sdl-1.2.15/src/audio/dma/SDL_dmaaudio.c @@ -0,0 +1,455 @@ +/* + SDL - Simple DirectMedia Layer + Copyright (C) 1997-2012 Sam Lantinga + + This library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + This library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this library; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + + Sam Lantinga + slouken@libsdl.org +*/ +#include "SDL_config.h" + +/* Allow access to a raw mixing buffer */ + +#include <stdio.h> +#include <string.h> /* For strerror() */ +#include <errno.h> +#include <unistd.h> +#include <fcntl.h> +#include <signal.h> +#include <sys/types.h> +#include <sys/time.h> +#include <sys/ioctl.h> +#include <sys/stat.h> +#include <sys/mman.h> + +#if SDL_AUDIO_DRIVER_OSS_SOUNDCARD_H +/* This is installed on some systems */ +#include <soundcard.h> +#else +/* This is recommended by OSS */ +#include <sys/soundcard.h> +#endif + +#ifndef MAP_FAILED +#define MAP_FAILED ((Uint8 *)-1) +#endif + +#include "SDL_timer.h" +#include "SDL_audio.h" +#include "../SDL_audio_c.h" +#include "../SDL_audiodev_c.h" +#include "SDL_dmaaudio.h" + +/* The tag name used by DMA audio */ +#define DMA_DRIVER_NAME "dma" + +/* Open the audio device for playback, and don't block if busy */ +#define OPEN_FLAGS (O_RDWR|O_NONBLOCK) + +/* Audio driver functions */ +static int DMA_OpenAudio(_THIS, SDL_AudioSpec *spec); +static void DMA_WaitAudio(_THIS); +static void DMA_PlayAudio(_THIS); +static Uint8 *DMA_GetAudioBuf(_THIS); +static void DMA_CloseAudio(_THIS); + +/* Audio driver bootstrap functions */ + +static int Audio_Available(void) +{ + int available; + int fd; + + available = 0; + + fd = SDL_OpenAudioPath(NULL, 0, OPEN_FLAGS, 0); + if ( fd >= 0 ) { + int caps; + struct audio_buf_info info; + + if ( (ioctl(fd, SNDCTL_DSP_GETCAPS, &caps) == 0) && + (caps & DSP_CAP_TRIGGER) && (caps & DSP_CAP_MMAP) && + (ioctl(fd, SNDCTL_DSP_GETOSPACE, &info) == 0) ) { + available = 1; + } + close(fd); + } + return(available); +} + +static void Audio_DeleteDevice(SDL_AudioDevice *device) +{ + SDL_free(device->hidden); + SDL_free(device); +} + +static SDL_AudioDevice *Audio_CreateDevice(int devindex) +{ + SDL_AudioDevice *this; + + /* Initialize all variables that we clean on shutdown */ + this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice)); + if ( this ) { + SDL_memset(this, 0, (sizeof *this)); + this->hidden = (struct SDL_PrivateAudioData *) + SDL_malloc((sizeof *this->hidden)); + } + if ( (this == NULL) || (this->hidden == NULL) ) { + SDL_OutOfMemory(); + if ( this ) { + SDL_free(this); + } + return(0); + } + SDL_memset(this->hidden, 0, (sizeof *this->hidden)); + audio_fd = -1; + + /* Set the function pointers */ + this->OpenAudio = DMA_OpenAudio; + this->WaitAudio = DMA_WaitAudio; + this->PlayAudio = DMA_PlayAudio; + this->GetAudioBuf = DMA_GetAudioBuf; + this->CloseAudio = DMA_CloseAudio; + + this->free = Audio_DeleteDevice; + + return this; +} + +AudioBootStrap DMA_bootstrap = { + DMA_DRIVER_NAME, "OSS /dev/dsp DMA audio", + Audio_Available, Audio_CreateDevice +}; + +/* This function waits until it is possible to write a full sound buffer */ +static void DMA_WaitAudio(_THIS) +{ + fd_set fdset; + + /* Check to see if the thread-parent process is still alive */ + { static int cnt = 0; + /* Note that this only works with thread implementations + that use a different process id for each thread. + */ + if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */ + if ( kill(parent, 0) < 0 ) { + this->enabled = 0; + } + } + } + + /* See if we need to use timed audio synchronization */ + if ( frame_ticks ) { + /* Use timer for general audio synchronization */ + Sint32 ticks; + + ticks = ((Sint32)(next_frame - SDL_GetTicks()))-FUDGE_TICKS; + if ( ticks > 0 ) { + SDL_Delay(ticks); + } + } else { + /* Use select() for audio synchronization */ + struct timeval timeout; + FD_ZERO(&fdset); + FD_SET(audio_fd, &fdset); + timeout.tv_sec = 10; + timeout.tv_usec = 0; +#ifdef DEBUG_AUDIO + fprintf(stderr, "Waiting for audio to get ready\n"); +#endif + if ( select(audio_fd+1, NULL, &fdset, NULL, &timeout) <= 0 ) { + const char *message = +#ifdef AUDIO_OSPACE_HACK + "Audio timeout - buggy audio driver? (trying ospace)"; +#else + "Audio timeout - buggy audio driver? (disabled)"; +#endif + /* In general we should never print to the screen, + but in this case we have no other way of letting + the user know what happened. + */ + fprintf(stderr, "SDL: %s\n", message); +#ifdef AUDIO_OSPACE_HACK + /* We may be able to use GET_OSPACE trick */ + frame_ticks = (float)(this->spec->samples*1000) / + this->spec->freq; + next_frame = SDL_GetTicks()+frame_ticks; +#else + this->enabled = 0; + /* Don't try to close - may hang */ + audio_fd = -1; +#ifdef DEBUG_AUDIO + fprintf(stderr, "Done disabling audio\n"); +#endif +#endif /* AUDIO_OSPACE_HACK */ + } +#ifdef DEBUG_AUDIO + fprintf(stderr, "Ready!\n"); +#endif + } +} + +static void DMA_PlayAudio(_THIS) +{ + /* If timer synchronization is enabled, set the next write frame */ + if ( frame_ticks ) { + next_frame += frame_ticks; + } + return; +} + +static Uint8 *DMA_GetAudioBuf(_THIS) +{ + count_info info; + int playing; + int filling; + + /* Get number of blocks, looping if we're not using select() */ + do { + if ( ioctl(audio_fd, SNDCTL_DSP_GETOPTR, &info) < 0 ) { + /* Uh oh... */ + this->enabled = 0; + return(NULL); + } + } while ( frame_ticks && (info.blocks < 1) ); +#ifdef DEBUG_AUDIO + if ( info.blocks > 1 ) { + printf("Warning: audio underflow (%d frags)\n", info.blocks-1); + } +#endif + playing = info.ptr / this->spec.size; + filling = (playing + 1)%num_buffers; + return (dma_buf + (filling * this->spec.size)); +} + +static void DMA_CloseAudio(_THIS) +{ + if ( dma_buf != NULL ) { + munmap(dma_buf, dma_len); + dma_buf = NULL; + } + if ( audio_fd >= 0 ) { + close(audio_fd); + audio_fd = -1; + } +} + +static int DMA_ReopenAudio(_THIS, const char *audiodev, int format, int stereo, + SDL_AudioSpec *spec) +{ + int frag_spec; + int value; + + /* Close and then reopen the audio device */ + close(audio_fd); + audio_fd = open(audiodev, O_RDWR, 0); + if ( audio_fd < 0 ) { + SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno)); + return(-1); + } + + /* Calculate the final parameters for this audio specification */ + SDL_CalculateAudioSpec(spec); + + /* Determine the power of two of the fragment size */ + for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec ); + if ( (0x01<<frag_spec) != spec->size ) { + SDL_SetError("Fragment size must be a power of two"); + return(-1); + } + + /* Set the audio buffering parameters */ + if ( ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0 ) { + SDL_SetError("Couldn't set audio fragment spec"); + return(-1); + } + + /* Set the audio format */ + value = format; + if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) || + (value != format) ) { + SDL_SetError("Couldn't set audio format"); + return(-1); + } + + /* Set mono or stereo audio */ + value = (spec->channels > 1); + if ( (ioctl(audio_fd, SNDCTL_DSP_STEREO, &stereo) < 0) || + (value != stereo) ) { + SDL_SetError("Couldn't set audio channels"); + return(-1); + } + + /* Set the DSP frequency */ + value = spec->freq; + if ( ioctl(audio_fd, SNDCTL_DSP_SPEED, &value) < 0 ) { + SDL_SetError("Couldn't set audio frequency"); + return(-1); + } + spec->freq = value; + + /* We successfully re-opened the audio */ + return(0); +} + +static int DMA_OpenAudio(_THIS, SDL_AudioSpec *spec) +{ + char audiodev[1024]; + int format; + int stereo; + int value; + Uint16 test_format; + struct audio_buf_info info; + + /* Reset the timer synchronization flag */ + frame_ticks = 0.0; + + /* Open the audio device */ + audio_fd = SDL_OpenAudioPath(audiodev, sizeof(audiodev), OPEN_FLAGS, 0); + if ( audio_fd < 0 ) { + SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno)); + return(-1); + } + dma_buf = NULL; + ioctl(audio_fd, SNDCTL_DSP_RESET, 0); + + /* Get a list of supported hardware formats */ + if ( ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0 ) { + SDL_SetError("Couldn't get audio format list"); + return(-1); + } + + /* Try for a closest match on audio format */ + format = 0; + for ( test_format = SDL_FirstAudioFormat(spec->format); + ! format && test_format; ) { +#ifdef DEBUG_AUDIO + fprintf(stderr, "Trying format 0x%4.4x\n", test_format); +#endif + switch ( test_format ) { + case AUDIO_U8: + if ( value & AFMT_U8 ) { + format = AFMT_U8; + } + break; + case AUDIO_S8: + if ( value & AFMT_S8 ) { + format = AFMT_S8; + } + break; + case AUDIO_S16LSB: + if ( value & AFMT_S16_LE ) { + format = AFMT_S16_LE; + } + break; + case AUDIO_S16MSB: + if ( value & AFMT_S16_BE ) { + format = AFMT_S16_BE; + } + break; + case AUDIO_U16LSB: + if ( value & AFMT_U16_LE ) { + format = AFMT_U16_LE; + } + break; + case AUDIO_U16MSB: + if ( value & AFMT_U16_BE ) { + format = AFMT_U16_BE; + } + break; + default: + format = 0; + break; + } + if ( ! format ) { + test_format = SDL_NextAudioFormat(); + } + } + if ( format == 0 ) { + SDL_SetError("Couldn't find any hardware audio formats"); + return(-1); + } + spec->format = test_format; + + /* Set the audio format */ + value = format; + if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) || + (value != format) ) { + SDL_SetError("Couldn't set audio format"); + return(-1); + } + + /* Set mono or stereo audio (currently only two channels supported) */ + stereo = (spec->channels > 1); + ioctl(audio_fd, SNDCTL_DSP_STEREO, &stereo); + if ( stereo ) { + spec->channels = 2; + } else { + spec->channels = 1; + } + + /* Because some drivers don't allow setting the buffer size + after setting the format, we must re-open the audio device + once we know what format and channels are supported + */ + if ( DMA_ReopenAudio(this, audiodev, format, stereo, spec) < 0 ) { + /* Error is set by DMA_ReopenAudio() */ + return(-1); + } + + /* Memory map the audio buffer */ + if ( ioctl(audio_fd, SNDCTL_DSP_GETOSPACE, &info) < 0 ) { + SDL_SetError("Couldn't get OSPACE parameters"); + return(-1); + } + spec->size = info.fragsize; + spec->samples = spec->size / ((spec->format & 0xFF) / 8); + spec->samples /= spec->channels; + num_buffers = info.fragstotal; + dma_len = num_buffers*spec->size; + dma_buf = (Uint8 *)mmap(NULL, dma_len, PROT_WRITE, MAP_SHARED, + audio_fd, 0); + if ( dma_buf == MAP_FAILED ) { + SDL_SetError("DMA memory map failed"); + dma_buf = NULL; + return(-1); + } + SDL_memset(dma_buf, spec->silence, dma_len); + + /* Check to see if we need to use select() workaround */ + { char *workaround; + workaround = SDL_getenv("SDL_DSP_NOSELECT"); + if ( workaround ) { + frame_ticks = (float)(spec->samples*1000)/spec->freq; + next_frame = SDL_GetTicks()+frame_ticks; + } + } + + /* Trigger audio playback */ + value = 0; + ioctl(audio_fd, SNDCTL_DSP_SETTRIGGER, &value); + value = PCM_ENABLE_OUTPUT; + if ( ioctl(audio_fd, SNDCTL_DSP_SETTRIGGER, &value) < 0 ) { + SDL_SetError("Couldn't trigger audio output"); + return(-1); + } + + /* Get the parent process id (we're the parent of the audio thread) */ + parent = getpid(); + + /* We're ready to rock and roll. :-) */ + return(0); +} |