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0
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1 /*
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2 SDL - Simple DirectMedia Layer
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3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
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4
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5 This library is free software; you can redistribute it and/or
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6 modify it under the terms of the GNU Library General Public
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7 License as published by the Free Software Foundation; either
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8 version 2 of the License, or (at your option) any later version.
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9
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10 This library is distributed in the hope that it will be useful,
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11 but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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13 Library General Public License for more details.
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14
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15 You should have received a copy of the GNU Library General Public
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16 License along with this library; if not, write to the Free
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17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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18
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19 Sam Lantinga
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20 slouken@devolution.com
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21 */
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22
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23 #ifdef SAVE_RCSID
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24 static char rcsid =
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25 "@(#) $Id$";
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26 #endif
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27
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28 /* Allow access to a raw mixing buffer */
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29
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30 #include <stdlib.h>
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31 #include <stdio.h>
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32 #include <string.h>
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33 #include <errno.h>
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34 #include <unistd.h>
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35 #include <fcntl.h>
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36 #include <signal.h>
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37 #include <sys/types.h>
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38 #include <sys/time.h>
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39 #include <sys/ioctl.h>
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40 #include <sys/stat.h>
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41 #include <sys/mman.h>
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42 #ifdef linux
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43 #include <linux/soundcard.h>
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44 #endif
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45 #ifdef __bsdi__
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46 #include <sys/soundcard.h>
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47 #endif
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48 #ifdef __FreeBSD__
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49 #include <machine/soundcard.h>
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50 #endif
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51 #ifdef __USLC__
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52 #include <sys/soundcard.h>
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53 #endif
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54
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55 #ifndef MAP_FAILED
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56 #define MAP_FAILED ((Uint8 *)-1)
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57 #endif
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58
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59 #include "SDL_audio.h"
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60 #include "SDL_error.h"
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61 #include "SDL_audiomem.h"
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62 #include "SDL_audio_c.h"
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63 #include "SDL_timer.h"
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64 #include "SDL_audiodev_c.h"
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65 #include "SDL_dmaaudio.h"
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66
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67 /* The tag name used by DMA audio */
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68 #define DMA_DRIVER_NAME "dma"
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69
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70 /* Open the audio device for playback, and don't block if busy */
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71 #define OPEN_FLAGS (O_RDWR|O_NONBLOCK)
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72
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73 /* Audio driver functions */
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74 static int DMA_OpenAudio(_THIS, SDL_AudioSpec *spec);
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75 static void DMA_WaitAudio(_THIS);
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76 static void DMA_PlayAudio(_THIS);
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77 static Uint8 *DMA_GetAudioBuf(_THIS);
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78 static void DMA_CloseAudio(_THIS);
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79
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80 /* Audio driver bootstrap functions */
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81
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82 static int Audio_Available(void)
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83 {
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84 int available;
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85 int fd;
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86
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87 available = 0;
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88
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89 fd = SDL_OpenAudioPath(NULL, 0, OPEN_FLAGS, 0);
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90 if ( fd >= 0 ) {
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91 int caps;
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92 struct audio_buf_info info;
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93
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94 if ( (ioctl(fd, SNDCTL_DSP_GETCAPS, &caps) == 0) &&
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95 (caps & DSP_CAP_TRIGGER) && (caps & DSP_CAP_MMAP) &&
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96 (ioctl(fd, SNDCTL_DSP_GETOSPACE, &info) == 0) ) {
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97 available = 1;
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98 }
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99 close(fd);
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100 }
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101 return(available);
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102 }
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103
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104 static void Audio_DeleteDevice(SDL_AudioDevice *device)
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105 {
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106 free(device->hidden);
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107 free(device);
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108 }
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109
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110 static SDL_AudioDevice *Audio_CreateDevice(int devindex)
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111 {
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112 SDL_AudioDevice *this;
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113
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114 /* Initialize all variables that we clean on shutdown */
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115 this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice));
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116 if ( this ) {
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117 memset(this, 0, (sizeof *this));
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118 this->hidden = (struct SDL_PrivateAudioData *)
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119 malloc((sizeof *this->hidden));
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120 }
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121 if ( (this == NULL) || (this->hidden == NULL) ) {
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122 SDL_OutOfMemory();
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123 if ( this ) {
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124 free(this);
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125 }
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126 return(0);
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127 }
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128 memset(this->hidden, 0, (sizeof *this->hidden));
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129 audio_fd = -1;
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130
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131 /* Set the function pointers */
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132 this->OpenAudio = DMA_OpenAudio;
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133 this->WaitAudio = DMA_WaitAudio;
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134 this->PlayAudio = DMA_PlayAudio;
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135 this->GetAudioBuf = DMA_GetAudioBuf;
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136 this->CloseAudio = DMA_CloseAudio;
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137
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138 this->free = Audio_DeleteDevice;
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139
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140 return this;
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141 }
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142
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143 AudioBootStrap DMA_bootstrap = {
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144 DMA_DRIVER_NAME, "OSS /dev/dsp DMA audio",
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145 Audio_Available, Audio_CreateDevice
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146 };
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147
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148 /* This function waits until it is possible to write a full sound buffer */
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149 static void DMA_WaitAudio(_THIS)
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150 {
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151 fd_set fdset;
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152
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153 /* Check to see if the thread-parent process is still alive */
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154 { static int cnt = 0;
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155 /* Note that this only works with thread implementations
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156 that use a different process id for each thread.
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157 */
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158 if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */
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159 if ( kill(parent, 0) < 0 ) {
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160 this->enabled = 0;
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161 }
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162 }
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163 }
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164
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165 /* See if we need to use timed audio synchronization */
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166 if ( frame_ticks ) {
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167 /* Use timer for general audio synchronization */
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168 Sint32 ticks;
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169
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170 ticks = ((Sint32)(next_frame - SDL_GetTicks()))-FUDGE_TICKS;
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171 if ( ticks > 0 ) {
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172 SDL_Delay(ticks);
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173 }
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174 } else {
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175 /* Use select() for audio synchronization */
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176 struct timeval timeout;
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177 FD_ZERO(&fdset);
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178 FD_SET(audio_fd, &fdset);
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179 timeout.tv_sec = 10;
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180 timeout.tv_usec = 0;
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181 #ifdef DEBUG_AUDIO
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182 fprintf(stderr, "Waiting for audio to get ready\n");
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183 #endif
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184 if ( select(audio_fd+1, NULL, &fdset, NULL, &timeout) <= 0 ) {
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185 const char *message =
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186 #ifdef AUDIO_OSPACE_HACK
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187 "Audio timeout - buggy audio driver? (trying ospace)";
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188 #else
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189 "Audio timeout - buggy audio driver? (disabled)";
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190 #endif
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191 /* In general we should never print to the screen,
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192 but in this case we have no other way of letting
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193 the user know what happened.
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194 */
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195 fprintf(stderr, "SDL: %s\n", message);
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196 #ifdef AUDIO_OSPACE_HACK
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197 /* We may be able to use GET_OSPACE trick */
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198 frame_ticks = (float)(this->spec->samples*1000) /
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199 this->spec->freq;
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200 next_frame = SDL_GetTicks()+frame_ticks;
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201 #else
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202 this->enabled = 0;
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203 /* Don't try to close - may hang */
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204 audio_fd = -1;
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205 #ifdef DEBUG_AUDIO
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206 fprintf(stderr, "Done disabling audio\n");
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207 #endif
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208 #endif /* AUDIO_OSPACE_HACK */
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209 }
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210 #ifdef DEBUG_AUDIO
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211 fprintf(stderr, "Ready!\n");
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212 #endif
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213 }
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214 }
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215
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216 static void DMA_PlayAudio(_THIS)
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217 {
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218 /* If timer synchronization is enabled, set the next write frame */
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219 if ( frame_ticks ) {
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220 next_frame += frame_ticks;
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221 }
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222 return;
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223 }
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224
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225 static Uint8 *DMA_GetAudioBuf(_THIS)
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226 {
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227 count_info info;
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228 int playing;
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229 int filling;
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230
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231 /* Get number of blocks, looping if we're not using select() */
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232 do {
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233 if ( ioctl(audio_fd, SNDCTL_DSP_GETOPTR, &info) < 0 ) {
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234 /* Uh oh... */
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235 this->enabled = 0;
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236 return(NULL);
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237 }
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238 } while ( frame_ticks && (info.blocks < 1) );
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239 #ifdef DEBUG_AUDIO
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240 if ( info.blocks > 1 ) {
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241 printf("Warning: audio underflow (%d frags)\n", info.blocks-1);
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242 }
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243 #endif
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244 playing = info.ptr / this->spec.size;
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245 filling = (playing + 1)%num_buffers;
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246 return (dma_buf + (filling * this->spec.size));
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247 }
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248
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249 static void DMA_CloseAudio(_THIS)
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250 {
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251 if ( dma_buf != NULL ) {
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252 munmap(dma_buf, dma_len);
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253 dma_buf = NULL;
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254 }
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255 if ( audio_fd >= 0 ) {
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256 close(audio_fd);
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257 audio_fd = -1;
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258 }
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259 }
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260
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261 static int DMA_ReopenAudio(_THIS, const char *audiodev, int format, int stereo,
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262 SDL_AudioSpec *spec)
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263 {
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264 int frag_spec;
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265 int value;
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266
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267 /* Close and then reopen the audio device */
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268 close(audio_fd);
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269 audio_fd = open(audiodev, O_RDWR, 0);
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270 if ( audio_fd < 0 ) {
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271 SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno));
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272 return(-1);
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273 }
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274 ioctl(audio_fd, SNDCTL_DSP_RESET, 0);
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275
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276 /* Calculate the final parameters for this audio specification */
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277 SDL_CalculateAudioSpec(spec);
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278
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279 /* Determine the power of two of the fragment size */
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280 for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec );
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281 if ( (0x01<<frag_spec) != spec->size ) {
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282 SDL_SetError("Fragment size must be a power of two");
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283 return(-1);
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284 }
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285
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286 /* Set the audio buffering parameters */
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287 if ( ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0 ) {
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288 SDL_SetError("Couldn't set audio fragment spec");
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289 return(-1);
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290 }
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291
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292 /* Set the audio format */
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293 value = format;
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294 if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
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295 (value != format) ) {
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296 SDL_SetError("Couldn't set audio format");
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297 return(-1);
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298 }
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299
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300 /* Set mono or stereo audio */
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301 value = (spec->channels > 1);
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302 if ( (ioctl(audio_fd, SNDCTL_DSP_STEREO, &stereo) < 0) ||
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303 (value != stereo) ) {
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304 SDL_SetError("Couldn't set audio channels");
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305 return(-1);
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306 }
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307
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308 /* Set the DSP frequency */
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309 value = spec->freq;
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310 if ( ioctl(audio_fd, SOUND_PCM_WRITE_RATE, &value) < 0 ) {
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311 SDL_SetError("Couldn't set audio frequency");
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312 return(-1);
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313 }
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314 spec->freq = value;
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315
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316 /* We successfully re-opened the audio */
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317 return(0);
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318 }
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319
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320 static int DMA_OpenAudio(_THIS, SDL_AudioSpec *spec)
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321 {
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322 char audiodev[1024];
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323 int format;
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324 int stereo;
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325 int value;
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326 Uint16 test_format;
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327 struct audio_buf_info info;
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328
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329 /* Reset the timer synchronization flag */
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330 frame_ticks = 0.0;
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331
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332 /* Open the audio device */
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333 audio_fd = SDL_OpenAudioPath(audiodev, sizeof(audiodev), OPEN_FLAGS, 0);
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334 if ( audio_fd < 0 ) {
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335 SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno));
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336 return(-1);
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337 }
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338 dma_buf = NULL;
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339 ioctl(audio_fd, SNDCTL_DSP_RESET, 0);
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340
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341 /* Get a list of supported hardware formats */
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342 if ( ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0 ) {
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343 SDL_SetError("Couldn't get audio format list");
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344 return(-1);
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345 }
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346
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347 /* Try for a closest match on audio format */
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348 format = 0;
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349 for ( test_format = SDL_FirstAudioFormat(spec->format);
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350 ! format && test_format; ) {
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351 #ifdef DEBUG_AUDIO
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352 fprintf(stderr, "Trying format 0x%4.4x\n", test_format);
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353 #endif
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354 switch ( test_format ) {
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355 case AUDIO_U8:
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356 if ( value & AFMT_U8 ) {
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357 format = AFMT_U8;
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358 }
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359 break;
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360 case AUDIO_S8:
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361 if ( value & AFMT_S8 ) {
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362 format = AFMT_S8;
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363 }
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364 break;
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365 case AUDIO_S16LSB:
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366 if ( value & AFMT_S16_LE ) {
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367 format = AFMT_S16_LE;
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368 }
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369 break;
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370 case AUDIO_S16MSB:
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371 if ( value & AFMT_S16_BE ) {
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372 format = AFMT_S16_BE;
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373 }
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374 break;
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375 case AUDIO_U16LSB:
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376 if ( value & AFMT_U16_LE ) {
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377 format = AFMT_U16_LE;
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378 }
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379 break;
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380 case AUDIO_U16MSB:
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381 if ( value & AFMT_U16_BE ) {
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382 format = AFMT_U16_BE;
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383 }
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384 break;
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385 default:
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386 break;
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387 }
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388 if ( ! format ) {
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389 test_format = SDL_NextAudioFormat();
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390 }
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391 }
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392 if ( format == 0 ) {
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393 SDL_SetError("Couldn't find any hardware audio formats");
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394 return(-1);
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395 }
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396 spec->format = test_format;
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397
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398 /* Set the audio format */
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399 value = format;
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400 if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
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401 (value != format) ) {
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402 SDL_SetError("Couldn't set audio format");
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403 return(-1);
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404 }
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405
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406 /* Set mono or stereo audio (currently only two channels supported) */
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407 stereo = (spec->channels > 1);
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408 ioctl(audio_fd, SNDCTL_DSP_STEREO, &stereo);
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409 if ( stereo ) {
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410 spec->channels = 2;
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411 } else {
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412 spec->channels = 1;
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413 }
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414
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415 /* Because some drivers don't allow setting the buffer size
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416 after setting the format, we must re-open the audio device
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417 once we know what format and channels are supported
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418 */
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419 if ( DMA_ReopenAudio(this, audiodev, format, stereo, spec) < 0 ) {
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420 /* Error is set by DMA_ReopenAudio() */
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421 return(-1);
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422 }
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423
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424 /* Memory map the audio buffer */
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425 if ( ioctl(audio_fd, SNDCTL_DSP_GETOSPACE, &info) < 0 ) {
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426 SDL_SetError("Couldn't get OSPACE parameters");
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427 return(-1);
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|
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428 }
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429 spec->size = info.fragsize;
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430 spec->samples = spec->size / ((spec->format & 0xFF) / 8);
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431 spec->samples /= spec->channels;
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432 num_buffers = info.fragstotal;
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433 dma_len = num_buffers*spec->size;
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434 dma_buf = (Uint8 *)mmap(NULL, dma_len, PROT_WRITE, MAP_SHARED,
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|
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435 audio_fd, 0);
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436 if ( dma_buf == MAP_FAILED ) {
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|
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437 SDL_SetError("DMA memory map failed");
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|
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438 dma_buf = NULL;
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|
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439 return(-1);
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|
|
440 }
|
|
|
441 memset(dma_buf, spec->silence, dma_len);
|
|
|
442
|
|
|
443 /* Check to see if we need to use select() workaround */
|
|
|
444 { char *workaround;
|
|
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445 workaround = getenv("SDL_DSP_NOSELECT");
|
|
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446 if ( workaround ) {
|
|
|
447 frame_ticks = (float)(spec->samples*1000)/spec->freq;
|
|
|
448 next_frame = SDL_GetTicks()+frame_ticks;
|
|
|
449 }
|
|
|
450 }
|
|
|
451
|
|
|
452 /* Trigger audio playback */
|
|
|
453 value = 0;
|
|
|
454 ioctl(audio_fd, SNDCTL_DSP_SETTRIGGER, &value);
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|
|
455 value = PCM_ENABLE_OUTPUT;
|
|
|
456 if ( ioctl(audio_fd, SNDCTL_DSP_SETTRIGGER, &value) < 0 ) {
|
|
|
457 SDL_SetError("Couldn't trigger audio output");
|
|
|
458 return(-1);
|
|
|
459 }
|
|
|
460
|
|
|
461 /* Get the parent process id (we're the parent of the audio thread) */
|
|
|
462 parent = getpid();
|
|
|
463
|
|
|
464 /* We're ready to rock and roll. :-) */
|
|
|
465 return(0);
|
|
|
466 }
|
