alsa_write.c

   1 /*
   2  * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file alsa_write.c paraslash's alsa output plugin */
   8
   9 /*
  10  * Based in parts on aplay.c from the alsa-utils-1.0.8 package,
  11  * Copyright (c) by Jaroslav Kysela <perex@suse.cz>, which is
  12  * based on the vplay program by Michael Beck.
  13  */
  14
  15 #include <regex.h>
  16 #include <sys/types.h>
  17 #include <dirent.h>
  18 #include <alsa/asoundlib.h>
  19 #include <sys/time.h>
  20 #include <stdbool.h>
  21
  22 #include "para.h"
  23 #include "fd.h"
  24 #include "string.h"
  25 #include "list.h"
  26 #include "sched.h"
  27 #include "ggo.h"
  28 #include "buffer_tree.h"
  29 #include "write.h"
  30 #include "write_common.h"
  31 #include "alsa_write.cmdline.h"
  32 #include "error.h"
  33
  34 /** always use 16 bit little endian */
  35 #define FORMAT SND_PCM_FORMAT_S16_LE
  36
  37 /** Data specific to the alsa writer. */
  38 struct private_alsa_write_data {
  39         /** The alsa handle */
  40         snd_pcm_t *handle;
  41         /** Determined and set by alsa_open(). */
  42         int bytes_per_frame; /* TODO: Kill this after btr switch */
  43         /** The approximate maximum buffer duration in us. */
  44         unsigned buffer_time;
  45         /* Number of frames that fit into the buffer. */
  46         snd_pcm_uframes_t buffer_frames;
  47         /**
  48          * The samplerate given by command line option or the decoder
  49          * of the writer node group.
  50          */
  51         unsigned samplerate;
  52         /**
  53          * The number of channels, given by command line option or the
  54          * decoder of the writer node group.
  55          */
  56         unsigned channels;
  57 };
  58
  59 /* Install PCM software and hardware configuration. */
  60 static int alsa_init(struct private_alsa_write_data *pad,
  61                 struct alsa_write_args_info *conf)
  62 {
  63         snd_pcm_hw_params_t *hwparams;
  64         snd_pcm_sw_params_t *swparams;
  65         snd_pcm_uframes_t start_threshold, stop_threshold;
  66         snd_pcm_uframes_t period_size;
  67         int err;
  68
  69         PARA_INFO_LOG("opening %s\n", conf->device_arg);
  70         err = snd_pcm_open(&pad->handle, conf->device_arg,
  71                 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  72         if (err < 0)
  73                 return -E_PCM_OPEN;
  74
  75         snd_pcm_hw_params_alloca(&hwparams);
  76         snd_pcm_sw_params_alloca(&swparams);
  77         if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
  78                 return -E_BROKEN_CONF;
  79         if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
  80                         SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
  81                 return -E_ACCESS_TYPE;
  82         if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0)
  83                 return -E_SAMPLE_FORMAT;
  84         if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
  85                         pad->channels) < 0)
  86                 return -E_CHANNEL_COUNT;
  87         if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
  88                         &pad->samplerate, NULL) < 0)
  89                 return -E_SET_RATE;
  90         err = snd_pcm_hw_params_get_buffer_time_max(hwparams,
  91                 &pad->buffer_time, NULL);
  92         if (err < 0 || !pad->buffer_time)
  93                 return -E_GET_BUFFER_TIME;
  94         PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
  95         if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
  96                         &pad->buffer_time, NULL) < 0)
  97                 return -E_SET_BUFFER_TIME;
  98         if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
  99                 return -E_HW_PARAMS;
 100         snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
 101         snd_pcm_hw_params_get_buffer_size(hwparams, &pad->buffer_frames);
 102         PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", pad->buffer_frames,
 103                 period_size);
 104         if (period_size == pad->buffer_frames)
 105                 return -E_BAD_PERIOD;
 106         snd_pcm_sw_params_current(pad->handle, swparams);
 107         snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
 108         if (pad->buffer_frames < 1)
 109                 start_threshold = 1;
 110         else
 111                 start_threshold = PARA_MIN(pad->buffer_frames,
 112                         (snd_pcm_uframes_t)pad->samplerate);
 113         if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 114                         start_threshold) < 0)
 115                 return -E_START_THRESHOLD;
 116         stop_threshold = pad->buffer_frames;
 117         if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 118                         stop_threshold) < 0)
 119                 return -E_STOP_THRESHOLD;
 120         if (snd_pcm_sw_params(pad->handle, swparams) < 0)
 121                 PARA_WARNING_LOG("unable to install sw params\n");
 122         pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
 123                 * pad->channels / 8;
 124         if (pad->bytes_per_frame <= 0)
 125                 return -E_PHYSICAL_WIDTH;
 126         PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame);
 127         if (snd_pcm_nonblock(pad->handle, 1))
 128                 PARA_ERROR_LOG("failed to set nonblock mode\n");
 129         return 1;
 130 }
 131
 132 /* Open an instance of the alsa writer. */
 133 static int alsa_open_nobtr(struct writer_node *wn)
 134 {
 135         struct alsa_write_args_info *conf = wn->conf;
 136         struct writer_node_group *wng = wn->wng;
 137         struct private_alsa_write_data *pad = para_calloc(sizeof(*pad));
 138
 139         wn->private_data = pad;
 140         if (!conf->samplerate_given && wng->samplerate)
 141                 pad->samplerate = *wng->samplerate;
 142         else
 143                 pad->samplerate = conf->samplerate_arg;
 144         if (!conf->channels_given && wng->channels)
 145                 pad->channels = *wng->channels;
 146         else
 147                 pad->channels = conf->channels_arg;
 148         PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
 149         return 1;
 150 }
 151
 152 static int alsa_open_btr(struct writer_node *wn)
 153 {
 154         struct private_alsa_write_data *pad = para_calloc(sizeof(*pad));
 155
 156         wn->private_data = pad;
 157         return 1;
 158 }
 159 static int alsa_open(struct writer_node *wn)
 160 {
 161         if (wn->btrn)
 162                 return alsa_open_btr(wn);
 163         return alsa_open_nobtr(wn);
 164 }
 165
 166 static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
 167 {
 168         struct private_alsa_write_data *pad = wn->private_data;
 169         struct writer_node_group *wng = wn->wng;
 170         struct timeval tv;
 171         snd_pcm_sframes_t avail, underrun;
 172
 173         if (!pad->handle)
 174                 return 1;
 175         if (wn->btrn) {
 176                 int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
 177                 if (ret == 0)
 178                         return 1;
 179                 if (ret < 0) {
 180                         sched_request_timeout_ms(20, s);
 181                         return 42;
 182                 }
 183         } else {
 184                 if (*wng->loaded - wn->written < pad->bytes_per_frame)
 185                         return 1;
 186         }
 187         /*
 188          * Data is available to be written to the alsa handle.  Compute number
 189          * of milliseconds until next buffer underrun would occur.
 190          *
 191          * snd_pcm_avail_update() updates the current available count of
 192          * samples for writing.  It is a light method to obtain current stream
 193          * position, because it does not require the user <-> kernel context
 194          * switch, but the value is less accurate, because ring buffer pointers
 195          * are updated in kernel drivers only when an interrupt occurs.
 196          */
 197         avail = snd_pcm_avail_update(pad->handle);
 198         if (avail < 0)
 199                 avail = 0;
 200         underrun = (pad->buffer_frames - avail) * pad->buffer_time
 201                 / pad->buffer_frames / 1000;
 202         if (underrun < 50)
 203                 underrun = 50;
 204         underrun -= 50;
 205         ms2tv(underrun, &tv);
 206         if (tv_diff(&s->timeout, &tv, NULL) > 0)
 207                 s->timeout = tv;
 208         //PARA_CRIT_LOG("timout: %lu\n", tv2ms(&s->timeout));
 209         return 1;
 210 }
 211
 212 static void alsa_write_pre_select_btr(struct sched *s, struct task *t)
 213 {
 214         struct writer_node *wn = container_of(t, struct writer_node, task);
 215         alsa_write_pre_select(s, wn);
 216 }
 217
 218 static void xrun(snd_pcm_t *handle)
 219 {
 220         snd_pcm_status_t *status;
 221         int ret;
 222         struct timeval tv, diff;
 223
 224         snd_pcm_status_alloca(&status);
 225         ret = snd_pcm_status(handle, status);
 226         if (ret < 0)
 227                 return;
 228         if (snd_pcm_status_get_state(status) != SND_PCM_STATE_XRUN)
 229                 return;
 230         snd_pcm_status_get_trigger_tstamp(status, &tv);
 231         tv_diff(now, &tv, &diff);
 232         PARA_WARNING_LOG("underrun: %lums\n", tv2ms(&diff));
 233 }
 234
 235 static int alsa_write_post_select(__a_unused struct sched *s,
 236                 struct writer_node *wn)
 237 {
 238         struct private_alsa_write_data *pad = wn->private_data;
 239         struct writer_node_group *wng = wn->wng;
 240         size_t bytes = *wng->loaded - wn->written;
 241         unsigned char *data = (unsigned char*)*wng->bufp + wn->written;
 242         snd_pcm_sframes_t ret, frames, avail;
 243
 244         if (*wng->input_error < 0 && (!pad->handle || bytes < pad->bytes_per_frame)) {
 245                 wn->written = *wng->loaded;
 246                 return *wng->input_error;
 247         }
 248         if (!bytes) /* no data available */
 249                 return 0;
 250         if (!pad->handle) {
 251                 int err = alsa_init(pad, wn->conf);
 252                 if (err < 0)
 253                         return err;
 254         }
 255         frames = bytes / pad->bytes_per_frame;
 256         if (!frames) /* less than a single frame available */
 257                 return 0;
 258         avail = snd_pcm_avail_update(pad->handle);
 259         if (avail <= 0)
 260                 return 0;
 261         frames = PARA_MIN(frames, avail);
 262         ret = snd_pcm_writei(pad->handle, data, frames);
 263         if (ret >= 0) {
 264                 wn->written += ret * pad->bytes_per_frame;
 265                 return 1;
 266         }
 267         if (ret == -EPIPE) {
 268                 xrun(pad->handle);
 269                 snd_pcm_prepare(pad->handle);
 270                 return 0;
 271         }
 272         PARA_WARNING_LOG("%s\n", snd_strerror(-ret));
 273         if (ret == -EAGAIN)
 274                 return 0;
 275         return -E_ALSA_WRITE;
 276 }
 277
 278 static void alsa_close(struct writer_node *wn)
 279 {
 280         struct private_alsa_write_data *pad = wn->private_data;
 281         PARA_INFO_LOG("closing writer node %p\n", wn);
 282
 283         if (pad->handle) {
 284                 /*
 285                  * It's OK to have a blocking operation here because we already
 286                  * made sure that the PCM output buffer is (nearly) empty.
 287                  */
 288                 snd_pcm_nonblock(pad->handle, 0);
 289                 snd_pcm_drain(pad->handle);
 290                 snd_pcm_close(pad->handle);
 291                 snd_config_update_free_global();
 292         }
 293         free(pad);
 294 }
 295
 296 static void alsa_write_post_select_btr(__a_unused struct sched *s,
 297                 struct task *t)
 298 {
 299         struct writer_node *wn = container_of(t, struct writer_node, task);
 300         struct private_alsa_write_data *pad = wn->private_data;
 301         struct btr_node *btrn = wn->btrn;
 302         char *data;
 303         size_t bytes;
 304         snd_pcm_sframes_t frames, avail;
 305         int ret;
 306
 307 again:
 308         t->error = 0;
 309         ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 310         if (ret == 0)
 311                 return;
 312         btr_merge(btrn, wn->min_iqs);
 313         bytes = btr_next_buffer(btrn, &data);
 314         if (ret < 0 || bytes < pad->bytes_per_frame) { /* eof */
 315                 assert(btr_no_parent(btrn));
 316                 ret = -E_ALSA_EOF;
 317                 if (!pad->handle)
 318                         goto err;
 319                 /* wait until pending frames are played */
 320                 avail = snd_pcm_avail_update(pad->handle);
 321                 if (avail + 1000 > pad->buffer_frames)
 322                         goto err;
 323                 PARA_DEBUG_LOG("waiting for device to drain\n");
 324                 return;
 325         }
 326         if (!pad->handle) {
 327                 struct alsa_write_args_info *conf = wn->conf;
 328                 if (bytes == 0) /* no data available */
 329                         return;
 330                 /* defaults */
 331                 pad->samplerate = conf->samplerate_arg;
 332                 pad->channels = conf->channels_arg;
 333                 if (!conf->samplerate_given) { /* config option trumps btr_exec */
 334                         int32_t rate;
 335                         if (get_btr_samplerate(btrn, &rate) >= 0)
 336                                 pad->samplerate = rate;
 337                 }
 338                 if (!conf->channels_given) {
 339                         int32_t ch;
 340                         if (get_btr_channels(btrn, &ch) >= 0)
 341                                 pad->channels = ch;
 342                 }
 343                 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
 344                 ret = 1;
 345                 ret = alsa_init(pad, wn->conf);
 346                 if (ret < 0)
 347                         goto err;
 348                 wn->min_iqs = pad->bytes_per_frame;
 349         }
 350         frames = bytes / pad->bytes_per_frame;
 351         frames = snd_pcm_writei(pad->handle, data, frames);
 352         if (frames >= 0) {
 353                 btr_consume(btrn, frames * pad->bytes_per_frame);
 354                 goto again;
 355         }
 356         if (frames == -EPIPE) {
 357                 xrun(pad->handle);
 358                 snd_pcm_prepare(pad->handle);
 359                 return;
 360         }
 361         if (frames == -EAGAIN)
 362                 return;
 363         PARA_WARNING_LOG("%s\n", snd_strerror(-frames));
 364         ret = -E_ALSA_WRITE;
 365 err:
 366         assert(ret < 0);
 367         btr_remove_node(btrn);
 368         t->error = ret;
 369 }
 370
 371 __malloc static void *alsa_parse_config(const char *options)
 372 {
 373         int ret;
 374         struct alsa_write_args_info *conf
 375                 = para_calloc(sizeof(struct alsa_write_args_info));
 376
 377         PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
 378         ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
 379         if (ret)
 380                 goto err_out;
 381         PARA_INFO_LOG("help given: %d\n", conf->help_given);
 382         return conf;
 383 err_out:
 384         free(conf);
 385         return NULL;
 386 }
 387
 388 static void alsa_free_config(void *conf)
 389 {
 390         alsa_cmdline_parser_free(conf);
 391 }
 392
 393 /**
 394  * The init function of the alsa writer.
 395  *
 396  * \param w Pointer to the writer to initialize.
 397  *
 398  * \sa \ref struct writer.
 399  */
 400 void alsa_write_init(struct writer *w)
 401 {
 402         struct alsa_write_args_info dummy;
 403
 404         alsa_cmdline_parser_init(&dummy);
 405         w->open = alsa_open;
 406         w->close = alsa_close;
 407         w->pre_select = alsa_write_pre_select;
 408         w->pre_select_btr = alsa_write_pre_select_btr;
 409         w->post_select = alsa_write_post_select;
 410         w->post_select_btr = alsa_write_post_select_btr;
 411         w->parse_config = alsa_parse_config;
 412         w->shutdown = NULL; /* nothing to do */
 413         w->free_config = alsa_free_config;
 414         w->help = (struct ggo_help) {
 415                 .short_help = alsa_write_args_info_help,
 416                 .detailed_help = alsa_write_args_info_detailed_help
 417         };
 418         alsa_cmdline_parser_free(&dummy);
 419 }