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