261 lines
6.3 KiB
C++
261 lines
6.3 KiB
C++
/*
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* \brief Genode-specific audio backend
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* \author Christian Prochaska
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* \author Sebastian Sumpf
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* \date 2012-03-13
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*
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* based on the dummy SDL audio driver
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*/
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/*
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* Copyright (C) 2012-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#include <base/allocator_avl.h>
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#include <base/printf.h>
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#include <base/thread.h>
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#include <audio_out_session/connection.h>
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#include <os/config.h>
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enum {
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AUDIO_CHANNELS = 2,
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};
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using Genode::env;
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using Genode::Allocator_avl;
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using Genode::Signal_context;
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using Genode::Signal_receiver;
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static const char *channel_names[] = { "front left", "front right" };
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static float volume = 1.0;
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static Signal_context config_signal_context;
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extern "C" {
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#include "SDL_config.h"
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/* Output audio to Genode audio service. */
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#include "SDL_rwops.h"
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#include "SDL_timer.h"
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#include "SDL_audio.h"
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#include "SDL_audiomem.h"
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#include "SDL_audio_c.h"
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#include "SDL_audiodev_c.h"
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#include "SDL_genodeaudio.h"
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/* The tag name used by Genode audio */
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#define GENODEAUD_DRIVER_NAME "genode"
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struct SDL_PrivateAudioData {
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Uint8 *mixbuf;
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Uint32 mixlen;
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Audio_out::Connection *audio[AUDIO_CHANNELS];
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};
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/*
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* The first 'Signal_receiver' object in a process creates a signal receiver
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* thread. Currently this must not happen before the main program has started
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* or else the thread's context area would get overmapped on Genode/Linux when
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* the main program calls 'main_thread_bootstrap()' from '_main()'.
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*/
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static Signal_receiver *signal_receiver()
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{
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static Signal_receiver _signal_receiver;
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return &_signal_receiver;
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}
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static void read_config()
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{
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/* read volume from config file */
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try {
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unsigned int config_volume;
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Genode::config()->xml_node().sub_node("sdl_audio_volume")
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.attribute("value").value(&config_volume);
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volume = (float)config_volume / 100;
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}
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catch (Genode::Xml_node::Nonexistent_sub_node) { }
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catch (Genode::Xml_node::Nonexistent_attribute) { }
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}
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/* Audio driver functions */
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static int GENODEAUD_OpenAudio(_THIS, SDL_AudioSpec *spec);
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static void GENODEAUD_WaitAudio(_THIS);
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static void GENODEAUD_PlayAudio(_THIS);
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static Uint8 *GENODEAUD_GetAudioBuf(_THIS);
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static void GENODEAUD_CloseAudio(_THIS);
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/* Audio driver bootstrap functions */
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static int GENODEAUD_Available(void)
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{
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return 1;
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}
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static void GENODEAUD_DeleteDevice(SDL_AudioDevice *device)
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{
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for (int channel = 0; channel < AUDIO_CHANNELS; channel++)
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destroy(env()->heap(), device->hidden->audio[channel]);
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SDL_free(device->hidden);
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SDL_free(device);
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}
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static SDL_AudioDevice *GENODEAUD_CreateDevice(int devindex)
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{
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SDL_AudioDevice *_this;
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/* Initialize all variables that we clean on shutdown */
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_this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));
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if ( _this ) {
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SDL_memset(_this, 0, (sizeof *_this));
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_this->hidden = (struct SDL_PrivateAudioData *)
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SDL_malloc((sizeof *_this->hidden));
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}
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if ( (_this == NULL) || (_this->hidden == NULL) ) {
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SDL_OutOfMemory();
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if ( _this ) {
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SDL_free(_this);
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}
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return(0);
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}
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SDL_memset(_this->hidden, 0, (sizeof *_this->hidden));
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/* Set the function pointers */
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_this->OpenAudio = GENODEAUD_OpenAudio;
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_this->WaitAudio = GENODEAUD_WaitAudio;
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_this->PlayAudio = GENODEAUD_PlayAudio;
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_this->GetAudioBuf = GENODEAUD_GetAudioBuf;
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_this->CloseAudio = GENODEAUD_CloseAudio;
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_this->free = GENODEAUD_DeleteDevice;
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/* connect to 'Audio_out' service */
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for (int channel = 0; channel < AUDIO_CHANNELS; channel++) {
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try {
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_this->hidden->audio[channel] = new (env()->heap())
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Audio_out::Connection(channel_names[channel]);
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_this->hidden->audio[channel]->start();
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} catch(Genode::Parent::Service_denied) {
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PERR("Could not connect to 'Audio_out' service.");
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while(--channel > 0)
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destroy(env()->heap(), _this->hidden->audio[channel]);
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return NULL;
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}
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}
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Genode::config()->sigh(signal_receiver()->manage(&config_signal_context));
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read_config();
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return _this;
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}
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AudioBootStrap GENODEAUD_bootstrap = {
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GENODEAUD_DRIVER_NAME, "Genode audio driver",
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GENODEAUD_Available, GENODEAUD_CreateDevice
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};
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/* This function waits until it is possible to write a full sound buffer */
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static void GENODEAUD_WaitAudio(_THIS)
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{
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for (int channel = 0; channel < AUDIO_CHANNELS; channel++) {
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Audio_out::Connection *connection = _this->hidden->audio[channel];
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/* wait until allocation is possible */
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if (connection->stream()->full())
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connection->wait_for_alloc();
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}
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}
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static void GENODEAUD_PlayAudio(_THIS)
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{
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Audio_out::Packet *p[AUDIO_CHANNELS];
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for (int channel = 0; channel < AUDIO_CHANNELS; channel++)
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while (1) {
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Audio_out::Connection *connection = _this->hidden->audio[channel];
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try {
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p[channel] = connection->stream()->alloc();
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break;
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} catch (Audio_out::Stream::Alloc_failed) {
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/* wait for next finished packet */
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connection->wait_for_alloc();
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}
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}
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if (signal_receiver()->pending()) {
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signal_receiver()->wait_for_signal();
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Genode::config()->reload();
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read_config();
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}
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for (int sample = 0; sample < Audio_out::PERIOD; sample++)
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for (int channel = 0; channel < AUDIO_CHANNELS; channel++)
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p[channel]->content()[sample] =
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volume * (float)(((int16_t*)_this->hidden->mixbuf)[sample * AUDIO_CHANNELS + channel]) / 32768;
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for (int channel = 0; channel < AUDIO_CHANNELS; channel++)
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_this->hidden->audio[channel]->submit(p[channel]);
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}
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static Uint8 *GENODEAUD_GetAudioBuf(_THIS)
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{
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return(_this->hidden->mixbuf);
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}
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static void GENODEAUD_CloseAudio(_THIS)
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{
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if ( _this->hidden->mixbuf != NULL ) {
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SDL_FreeAudioMem(_this->hidden->mixbuf);
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_this->hidden->mixbuf = NULL;
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}
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}
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static int GENODEAUD_OpenAudio(_THIS, SDL_AudioSpec *spec)
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{
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PDBG("requested freq = %d", spec->freq);
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PDBG("requested format = 0x%x", spec->format);
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PDBG("requested samples = %u", spec->samples);
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PDBG("requested size = %u", spec->size);
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spec->channels = AUDIO_CHANNELS;
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spec->format = AUDIO_S16LSB;
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spec->freq = Audio_out::SAMPLE_RATE;
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spec->samples = Audio_out::PERIOD;
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SDL_CalculateAudioSpec(spec);
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/* Allocate mixing buffer */
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_this->hidden->mixlen = spec->size;
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_this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(_this->hidden->mixlen);
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if ( _this->hidden->mixbuf == NULL ) {
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return(-1);
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}
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SDL_memset(_this->hidden->mixbuf, spec->silence, spec->size);
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/* We're ready to rock and roll. :-) */
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return(0);
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}
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}
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