src/alsa.c

   1 /*
   2  * transsip - the telephony toolkit
   3  * By Daniel Borkmann <daniel@transsip.org>
   4  * Copyright 2011-2012 Daniel Borkmann <dborkma@tik.ee.ethz.ch>,
   5  * Swiss federal institute of technology (ETH Zurich)
   6  * Copyright 2004-2006 Jean-Marc Valin
   7  * Copyright 2006 Commonwealth Scientific and Industrial Research
   8  *                Organisation (CSIRO) Australia (2-clause BSD)
   9  * Subject to the GPL, version 2.
  10  */
  11
  12 #include <stdlib.h>
  13 #include <sys/poll.h>
  14 #include <alsa/asoundlib.h>
  15
  16 #include "built-in.h"
  17 #include "die.h"
  18 #include "alsa.h"
  19 #include "xmalloc.h"
  20
  21 #define PERIODS 3
  22
  23 struct alsa_dev {
  24         char *name;
  25         int channels;
  26         int period;
  27         snd_pcm_t *capture_handle;
  28         snd_pcm_t *playback_handle;
  29         unsigned int read_fds;
  30         struct pollfd *read_fd;
  31         unsigned int write_fds;
  32         struct pollfd *write_fd;
  33 };
  34
  35 static void alsa_set_hw_params(struct alsa_dev *dev, snd_pcm_t *handle,
  36                                unsigned int rate, int channels, int period)
  37 {
  38         int dir, ret;
  39         snd_pcm_uframes_t period_size;
  40         snd_pcm_uframes_t buffer_size;
  41         snd_pcm_hw_params_t *hw_params;
  42
  43         ret = snd_pcm_hw_params_malloc(&hw_params);
  44         if (ret < 0)
  45                 panic("Cannot allocate hardware parameters: %s\n",
  46                       snd_strerror(ret));
  47
  48         ret = snd_pcm_hw_params_any(handle, hw_params);
  49         if (ret < 0)
  50                 panic("Cannot initialize hardware parameters: %s\n",
  51                       snd_strerror(ret));
  52
  53         ret = snd_pcm_hw_params_set_access(handle, hw_params,
  54                                            SND_PCM_ACCESS_RW_INTERLEAVED);
  55         if (ret < 0)
  56                 panic("Cannot set access type: %s\n",
  57                       snd_strerror(ret));
  58
  59         ret = snd_pcm_hw_params_set_format(handle, hw_params,
  60                                            SND_PCM_FORMAT_S16_LE);
  61         if (ret < 0)
  62                 panic("Cannot set sample format: %s\n",
  63                       snd_strerror(ret));
  64
  65         ret = snd_pcm_hw_params_set_rate_near(handle, hw_params, &rate, 0);
  66         if (ret < 0)
  67                 panic("Cannot set sample rate: %s\n",
  68                       snd_strerror(ret));
  69
  70         ret = snd_pcm_hw_params_set_channels(handle, hw_params, channels);
  71         if (ret < 0)
  72                 panic("Cannot set channel number: %s\n",
  73                       snd_strerror(ret));
  74
  75         period_size = period;
  76         dir = 0;
  77         ret = snd_pcm_hw_params_set_period_size_near(handle, hw_params,
  78                                                      &period_size, &dir);
  79         if (ret < 0)
  80                 panic("Cannot set period size: %s\n",
  81                       snd_strerror(ret));
  82
  83         ret = snd_pcm_hw_params_set_periods(handle, hw_params, PERIODS, 0);
  84         if (ret < 0)
  85                 panic("Cannot set period number: %s\n",
  86                       snd_strerror(ret));
  87
  88         buffer_size = period_size * PERIODS;
  89         dir = 0;
  90         ret = snd_pcm_hw_params_set_buffer_size_near(handle, hw_params,
  91                                                      &buffer_size);
  92         if (ret < 0)
  93                 panic("Cannot set buffer size: %s\n",
  94                       snd_strerror(ret));
  95
  96         ret = snd_pcm_hw_params(handle, hw_params);
  97         if (ret < 0)
  98                 panic("Cannot set capture parameters: %s\n",
  99                       snd_strerror(ret));
 100
 101         snd_pcm_hw_params_free(hw_params);
 102 }
 103
 104 static void alsa_set_sw_params(struct alsa_dev *dev, snd_pcm_t *handle,
 105                                int period, int thres)
 106 {
 107         int ret;
 108         snd_pcm_sw_params_t *sw_params;
 109
 110         ret = snd_pcm_sw_params_malloc(&sw_params);
 111         if (ret < 0)
 112                 panic("Cannot allocate software parameters: %s\n",
 113                       snd_strerror(ret));
 114
 115         ret = snd_pcm_sw_params_current(handle, sw_params);
 116         if (ret < 0)
 117                 panic("Cannot initialize software parameters: %s\n",
 118                       snd_strerror(ret));
 119
 120         ret = snd_pcm_sw_params_set_avail_min(handle, sw_params, period);
 121         if (ret < 0)
 122                 panic("Cannot set minimum available count: %s\n",
 123                       snd_strerror(ret));
 124
 125         if (thres) {
 126                 ret = snd_pcm_sw_params_set_start_threshold(handle, sw_params,
 127                                                             period);
 128                 if (ret < 0)
 129                         panic("Cannot set start mode: %s\n",
 130                               snd_strerror(ret));
 131
 132         }
 133
 134         ret = snd_pcm_sw_params(handle, sw_params);
 135         if (ret < 0)
 136                 panic("Cannot set software parameters: %s\n",
 137                       snd_strerror(ret));
 138
 139         snd_pcm_sw_params_free(sw_params);
 140 }
 141
 142 struct alsa_dev *alsa_open(char *devname, unsigned int rate,
 143                            int channels, int period)
 144 {
 145         int ret;
 146         struct alsa_dev *dev;
 147
 148         if (!devname)
 149                 devname = "plughw:0,0";
 150
 151         dev = xzmalloc(sizeof(*dev));
 152         dev->name = xstrdup(devname);
 153         dev->channels = channels;
 154         dev->period = period;
 155
 156         ret = snd_pcm_open(&dev->capture_handle, dev->name,
 157                            SND_PCM_STREAM_CAPTURE, 0);
 158         if (ret < 0)
 159                 panic("Cannot open audio capture device %s: %s\n",
 160                       dev->name, snd_strerror(ret));
 161
 162         alsa_set_hw_params(dev, dev->capture_handle, rate, channels, period);
 163         alsa_set_sw_params(dev, dev->capture_handle, period, 0);
 164
 165         ret = snd_pcm_open(&dev->playback_handle, dev->name,
 166                            SND_PCM_STREAM_PLAYBACK, 0);
 167         if (ret < 0)
 168                 panic("Cannot open audio playback device %s: %s\n",
 169                       dev->name, snd_strerror(ret));
 170
 171         alsa_set_hw_params(dev, dev->playback_handle, rate, channels, period);
 172         alsa_set_sw_params(dev, dev->playback_handle, period, 1);
 173
 174         snd_pcm_link(dev->capture_handle, dev->playback_handle);
 175
 176         ret = snd_pcm_prepare(dev->capture_handle);
 177         if (ret < 0)
 178                 panic("Cannot prepare audio interface: %s\n",
 179                       snd_strerror(ret));
 180
 181         ret = snd_pcm_prepare(dev->playback_handle);
 182         if (ret < 0)
 183                 panic("Cannot prepare audio interface: %s\n",
 184                       snd_strerror(ret));
 185
 186         dev->read_fds = snd_pcm_poll_descriptors_count(dev->capture_handle);
 187         dev->write_fds = snd_pcm_poll_descriptors_count(dev->playback_handle);
 188         dev->read_fd = xzmalloc(dev->read_fds * sizeof(*dev->read_fd));
 189
 190         ret = snd_pcm_poll_descriptors(dev->capture_handle, dev->read_fd,
 191                                        dev->read_fds);
 192         if (ret != dev->read_fds)
 193                 panic("Cannot obtain capture file descriptors: %s\n",
 194                       snd_strerror(ret));
 195
 196         dev->write_fd = xzmalloc(dev->write_fds * sizeof(*dev->write_fd));
 197
 198         ret = snd_pcm_poll_descriptors(dev->playback_handle, dev->write_fd,
 199                                        dev->write_fds);
 200         if (ret != dev->write_fds)
 201                 panic("Cannot obtain playback file descriptors: %s\n",
 202                       snd_strerror(ret));
 203
 204         return dev;
 205 }
 206
 207 void alsa_close(struct alsa_dev *dev)
 208 {
 209         snd_pcm_close(dev->capture_handle);
 210         snd_pcm_close(dev->playback_handle);
 211
 212         xfree(dev->name);
 213         xfree(dev->read_fd);
 214         xfree(dev->write_fd);
 215         xfree(dev);
 216 }
 217
 218 ssize_t alsa_read(struct alsa_dev *dev, short *pcm, size_t len)
 219 {
 220         ssize_t ret = snd_pcm_readi(dev->capture_handle, pcm, len);
 221         if (unlikely(ret != len)) {
 222                 if (ret < 0) {
 223                         ret = snd_pcm_prepare(dev->capture_handle);
 224                         if (unlikely(ret < 0))
 225                                 printf("Error preparing interface: %s\n",
 226                                        snd_strerror(ret));
 227
 228                         ret = snd_pcm_start(dev->capture_handle);
 229                         if (unlikely(ret < 0))
 230                                 printf("Error preparing interface: %s\n",
 231                                        snd_strerror(ret));
 232                 }
 233                 return 1;
 234         }
 235         return 0;
 236 }
 237
 238 ssize_t alsa_write(struct alsa_dev *dev, const short *pcm, size_t len)
 239 {
 240         ssize_t ret = snd_pcm_writei(dev->playback_handle, pcm, len);
 241         if (unlikely(ret != len)) {
 242                 if (ret < 0) {
 243                         ret = snd_pcm_prepare(dev->playback_handle);
 244                         if (unlikely(ret < 0))
 245                                 printf("Error preparing interface: %s\n",
 246                                        snd_strerror(ret));
 247                 }
 248                 return 1;
 249         }
 250         return 0;
 251 }
 252
 253 int alsa_cap_ready(struct alsa_dev *dev, struct pollfd *pfds,
 254                    unsigned int nfds)
 255 {
 256         int ret;
 257         unsigned short revents = 0;
 258
 259         ret = snd_pcm_poll_descriptors_revents(dev->capture_handle, pfds,
 260                                                dev->read_fds, &revents);
 261         if (ret < 0) {
 262                 whine("Error in alsa_cap_ready: %s\n", snd_strerror(ret));
 263                 return pfds[0].revents & POLLIN;
 264         }
 265
 266         return revents & POLLIN;
 267 }
 268
 269 int alsa_play_ready(struct alsa_dev *dev, struct pollfd *pfds,
 270                     unsigned int nfds)
 271 {
 272         int ret;
 273         unsigned short revents = 0;
 274
 275         ret = snd_pcm_poll_descriptors_revents(dev->playback_handle,
 276                                                pfds + dev->read_fds,
 277                                                dev->write_fds, &revents);
 278         if (ret < 0) {
 279                 whine("Error in alsa_play_ready: %s\n", snd_strerror(ret));
 280                 return pfds[1].revents & POLLOUT;
 281         }
 282
 283         return revents & POLLOUT;
 284 }
 285
 286 void alsa_start(struct alsa_dev *dev)
 287 {
 288         short *pcm;
 289         size_t len = dev->period * dev->channels;
 290
 291         pcm = xzmalloc(len * sizeof(*pcm));
 292
 293         alsa_write(dev, pcm, dev->period);
 294         alsa_write(dev, pcm, dev->period);
 295
 296         xfree(pcm);
 297
 298         snd_pcm_start(dev->capture_handle);
 299         snd_pcm_start(dev->playback_handle);
 300 }
 301
 302 void alsa_stop(struct alsa_dev *dev)
 303 {
 304 }
 305
 306 inline unsigned int alsa_nfds(struct alsa_dev *dev)
 307 {
 308         return dev->read_fds + dev->write_fds;
 309 }
 310
 311 void alsa_getfds(struct alsa_dev *dev, struct pollfd *pfds,
 312                  unsigned int nfds)
 313 {
 314         int i;
 315
 316         for (i = 0; i < dev->read_fds; ++i)
 317                 pfds[i] = dev->read_fd[i];
 318
 319         for (i = 0; i < dev->write_fds; ++i)
 320                 pfds[i + dev->read_fds] = dev->write_fd[i];
 321 }