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Diffstat (limited to 'src/audio/dma/SDL_dmaaudio.c')
-rw-r--r--src/audio/dma/SDL_dmaaudio.c455
1 files changed, 455 insertions, 0 deletions
diff --git a/src/audio/dma/SDL_dmaaudio.c b/src/audio/dma/SDL_dmaaudio.c
new file mode 100644
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--- /dev/null
+++ b/src/audio/dma/SDL_dmaaudio.c
@@ -0,0 +1,455 @@
+/*
+ SDL - Simple DirectMedia Layer
+ Copyright (C) 1997-2009 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);
+}
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