alsa_write.c

   1 /*
   2  * Copyright (C) 2005-2013 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 <alsa/asoundlib.h>
  18
  19 #include "para.h"
  20 #include "fd.h"
  21 #include "string.h"
  22 #include "list.h"
  23 #include "sched.h"
  24 #include "ggo.h"
  25 #include "buffer_tree.h"
  26 #include "write.h"
  27 #include "write_common.h"
  28 #include "alsa_write.cmdline.h"
  29 #include "error.h"
  30
  31 /** Data specific to the alsa writer. */
  32 struct private_alsa_write_data {
  33         /** The alsa handle */
  34         snd_pcm_t *handle;
  35         /** Determined and set by alsa_init(). */
  36         int bytes_per_frame;
  37         /**
  38          * The sample rate given by command line option or the decoder
  39          * of the writer node group.
  40          */
  41         unsigned sample_rate;
  42         snd_pcm_format_t sample_format;
  43         /**
  44          * The number of channels, given by command line option or the
  45          * decoder of the writer node group.
  46          */
  47         unsigned channels;
  48         struct timeval drain_barrier;
  49         /* File descriptor for select(). */
  50         int poll_fd;
  51 };
  52
  53 static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf)
  54 {
  55         switch (sf) {
  56         case SF_S8: return SND_PCM_FORMAT_S8;
  57         case SF_U8: return SND_PCM_FORMAT_U8;
  58         case SF_S16_LE: return SND_PCM_FORMAT_S16_LE;
  59         case SF_S16_BE: return SND_PCM_FORMAT_S16_BE;
  60         case SF_U16_LE: return SND_PCM_FORMAT_U16_LE;
  61         case SF_U16_BE: return SND_PCM_FORMAT_U16_BE;
  62         default: return SND_PCM_FORMAT_S16_LE;
  63         }
  64 }
  65
  66 /* Install PCM software and hardware configuration. */
  67 static int alsa_init(struct private_alsa_write_data *pad,
  68                 struct alsa_write_args_info *conf)
  69 {
  70         snd_pcm_hw_params_t *hwparams;
  71         snd_pcm_sw_params_t *swparams;
  72         snd_pcm_uframes_t start_threshold, stop_threshold;
  73         snd_pcm_uframes_t buffer_size, period_size;
  74         snd_output_t *output_log;
  75         unsigned buffer_time;
  76         int ret;
  77         const char *msg;
  78
  79         PARA_INFO_LOG("opening %s\n", conf->device_arg);
  80         msg = "unable to open pcm";
  81         ret = snd_pcm_open(&pad->handle, conf->device_arg,
  82                 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  83         if (ret < 0)
  84                 goto fail;
  85         snd_pcm_hw_params_alloca(&hwparams);
  86         msg = "Broken alsa configuration";
  87         ret = snd_pcm_hw_params_any(pad->handle, hwparams);
  88         if (ret < 0)
  89                 goto fail;
  90         msg = "access type not available";
  91         ret = snd_pcm_hw_params_set_access(pad->handle, hwparams,
  92                 SND_PCM_ACCESS_RW_INTERLEAVED);
  93         if (ret < 0)
  94                 goto fail;
  95         msg = "sample format not available";
  96         ret = snd_pcm_hw_params_set_format(pad->handle, hwparams,
  97                 pad->sample_format);
  98         if (ret < 0)
  99                 goto fail;
 100         msg = "channels count not available";
 101         ret = snd_pcm_hw_params_set_channels(pad->handle, hwparams,
 102                 pad->channels);
 103         if (ret < 0)
 104                 goto fail;
 105         msg = "could not set sample rate";
 106         ret = snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
 107                 &pad->sample_rate, NULL);
 108         if (ret < 0)
 109                 goto fail;
 110         msg = "unable to get buffer time";
 111         ret = snd_pcm_hw_params_get_buffer_time_max(hwparams, &buffer_time,
 112                 NULL);
 113         if (ret < 0 || buffer_time == 0)
 114                 goto fail;
 115         /* buffer at most 500 milliseconds */
 116         buffer_time = PARA_MIN(buffer_time, 500U * 1000U);
 117         msg = "could not set buffer time";
 118         ret = snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
 119                 &buffer_time, NULL);
 120         if (ret < 0)
 121                 goto fail;
 122         msg = "unable to install hw params";
 123         ret = snd_pcm_hw_params(pad->handle, hwparams);
 124         if (ret < 0)
 125                 goto fail;
 126         snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
 127         snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
 128         msg = "period size equals buffer size";
 129         if (period_size == buffer_size)
 130                 goto fail;
 131
 132         /* software parameter setup */
 133         snd_pcm_sw_params_alloca(&swparams);
 134         snd_pcm_sw_params_current(pad->handle, swparams);
 135         snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
 136         if (buffer_size < 1)
 137                 start_threshold = 1;
 138         else
 139                 start_threshold = PARA_MIN(buffer_size,
 140                         (snd_pcm_uframes_t)pad->sample_rate);
 141         msg = "could not set start threshold";
 142         ret = snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 143                 start_threshold);
 144         if (ret < 0)
 145                 goto fail;
 146         stop_threshold = buffer_size;
 147         msg = "could not set stop threshold";
 148         ret = snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 149                 stop_threshold);
 150         if (ret < 0)
 151                 goto fail;
 152         msg = "unable to install sw params";
 153         ret = snd_pcm_sw_params(pad->handle, swparams);
 154         if (ret < 0)
 155                 goto fail;
 156         msg = "unable to determine bytes per frame";
 157         ret = snd_pcm_format_physical_width(pad->sample_format);
 158         if (ret <= 0)
 159                 goto fail;
 160         pad->bytes_per_frame = ret * pad->channels / 8;
 161         msg = "failed to set alsa handle to nonblock mode";
 162         ret = snd_pcm_nonblock(pad->handle, 1);
 163         if (ret < 0)
 164                 goto fail;
 165         ret = snd_output_buffer_open(&output_log);
 166         if (ret == 0) {
 167                 char *buf, *p;
 168                 size_t sz;
 169                 PARA_INFO_LOG("dumping alsa configuration\n");
 170                 snd_pcm_dump(pad->handle, output_log);
 171                 sz = snd_output_buffer_string(output_log, &buf);
 172                 for (p = buf; p < buf + sz;) {
 173                         char *q = memchr(p, '\n', buf + sz - p);
 174                         if (!q)
 175                                 break;
 176                         *q = '\0';
 177                         PARA_INFO_LOG("%s\n", p);
 178                         p = q + 1;
 179                 }
 180                 snd_output_close(output_log);
 181         }
 182         return 1;
 183 fail:
 184         if (ret < 0)
 185                 PARA_ERROR_LOG("%s: %s\n", msg, snd_strerror(-ret));
 186         else
 187                 PARA_ERROR_LOG("%s\n", msg);
 188         return -E_ALSA;
 189 }
 190
 191 static void alsa_write_pre_select(struct sched *s, struct task *t)
 192 {
 193         struct pollfd pfd;
 194         struct writer_node *wn = container_of(t, struct writer_node, task);
 195         struct private_alsa_write_data *pad = wn->private_data;
 196         int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
 197
 198         if (pad)
 199                 pad->poll_fd = -1;
 200         if (ret == 0)
 201                 return;
 202         if (!pad) {
 203                 sched_min_delay(s);
 204                 return;
 205         }
 206         if (ret < 0) {
 207                 sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
 208                 return;
 209         }
 210         ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
 211         if (ret < 0) {
 212                 PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
 213                         snd_strerror(-ret));
 214                 t->error = -E_ALSA;
 215                 return;
 216         }
 217         pad->poll_fd = pfd.fd;
 218         para_fd_set(pfd.fd, &s->rfds, &s->max_fileno);
 219 }
 220
 221 static void alsa_close(struct writer_node *wn)
 222 {
 223         struct private_alsa_write_data *pad = wn->private_data;
 224         PARA_INFO_LOG("closing writer node %p\n", wn);
 225
 226         if (!pad)
 227                 return;
 228         /*
 229          * It's OK to have a blocking operation here because we already made
 230          * sure that the PCM output buffer is (nearly) empty.
 231          */
 232         snd_pcm_nonblock(pad->handle, 0);
 233         snd_pcm_drain(pad->handle);
 234         snd_pcm_close(pad->handle);
 235         snd_config_update_free_global();
 236         free(pad);
 237 }
 238
 239 static int alsa_write_post_select(__a_unused struct sched *s,
 240                 struct task *t)
 241 {
 242         struct writer_node *wn = container_of(t, struct writer_node, task);
 243         struct private_alsa_write_data *pad = wn->private_data;
 244         struct btr_node *btrn = wn->btrn;
 245         char *data;
 246         size_t bytes;
 247         snd_pcm_sframes_t frames;
 248         int ret;
 249
 250         ret = task_get_notification(t);
 251         if (ret < 0)
 252                 goto err;
 253 again:
 254         ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 255         if (ret == 0)
 256                 return 0;
 257         btr_merge(btrn, wn->min_iqs);
 258         bytes = btr_next_buffer(btrn, &data);
 259         if (ret < 0 || bytes < wn->min_iqs) { /* eof */
 260                 assert(btr_no_parent(btrn));
 261                 ret = -E_WRITE_COMMON_EOF;
 262                 if (!pad)
 263                         goto err;
 264                 /* wait until pending frames are played */
 265                 if (pad->drain_barrier.tv_sec == 0) {
 266                         PARA_DEBUG_LOG("waiting for device to drain\n");
 267                         tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
 268                                 &pad->drain_barrier);
 269                         return 0;
 270                 }
 271                 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
 272                         goto err;
 273                 return 0;
 274         }
 275         if (!pad) {
 276                 int32_t val;
 277
 278                 if (bytes == 0) /* no data available */
 279                         return 0;
 280                 pad = para_calloc(sizeof(*pad));
 281                 get_btr_sample_rate(btrn, &val);
 282                 pad->sample_rate = val;
 283                 get_btr_channels(btrn, &val);
 284                 pad->channels = val;
 285                 get_btr_sample_format(btrn, &val);
 286                 pad->sample_format = get_alsa_pcm_format(val);
 287
 288                 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
 289                         pad->sample_rate);
 290                 ret = alsa_init(pad, wn->conf);
 291                 if (ret < 0) {
 292                         free(pad);
 293                         goto err;
 294                 }
 295                 wn->private_data = pad;
 296                 wn->min_iqs = pad->bytes_per_frame;
 297                 goto again;
 298         }
 299         if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds))
 300                 return 0;
 301         frames = bytes / pad->bytes_per_frame;
 302         frames = snd_pcm_writei(pad->handle, data, frames);
 303         if (frames == 0 || frames == -EAGAIN) {
 304                 /*
 305                  * The alsa poll fd was ready for IO but we failed to write to
 306                  * the alsa handle. This means another event is pending. We
 307                  * don't care about that but we have to dispatch the event in
 308                  * order to avoid a busy loop. So we simply read from the poll
 309                  * fd.
 310                  */
 311                 char buf[100];
 312                 if (read(pad->poll_fd, buf, 100))
 313                         do_nothing;
 314                 return 0;
 315         }
 316         if (frames > 0) {
 317                 btr_consume(btrn, frames * pad->bytes_per_frame);
 318                 goto again;
 319         }
 320         if (frames == -EPIPE) {
 321                 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
 322                 snd_pcm_prepare(pad->handle);
 323                 return 0;
 324         }
 325         PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames));
 326         ret = -E_ALSA;
 327 err:
 328         assert(ret < 0);
 329         btr_remove_node(&wn->btrn);
 330         return ret;
 331 }
 332
 333 __malloc static void *alsa_parse_config_or_die(int argc, char **argv)
 334 {
 335         struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
 336
 337         /* exits on errors */
 338         alsa_write_cmdline_parser(argc, argv, conf);
 339         return conf;
 340 }
 341
 342 static void alsa_free_config(void *conf)
 343 {
 344         alsa_write_cmdline_parser_free(conf);
 345 }
 346
 347 /**
 348  * The init function of the alsa writer.
 349  *
 350  * \param w Pointer to the writer to initialize.
 351  *
 352  * \sa struct \ref writer.
 353  */
 354 void alsa_write_init(struct writer *w)
 355 {
 356         struct alsa_write_args_info dummy;
 357
 358         alsa_write_cmdline_parser_init(&dummy);
 359         w->close = alsa_close;
 360         w->pre_select = alsa_write_pre_select;
 361         w->post_select = alsa_write_post_select;
 362         w->parse_config_or_die = alsa_parse_config_or_die;
 363         w->free_config = alsa_free_config;
 364         w->help = (struct ggo_help) {
 365                 .short_help = alsa_write_args_info_help,
 366                 .detailed_help = alsa_write_args_info_detailed_help
 367         };
 368         alsa_write_cmdline_parser_free(&dummy);
 369 }