alsa_write.c

   1 /*
   2  * Copyright (C) 2005-2011 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 #include <sys/time.h>
  19 #include <stdbool.h>
  20
  21 #include "para.h"
  22 #include "fd.h"
  23 #include "string.h"
  24 #include "list.h"
  25 #include "sched.h"
  26 #include "ggo.h"
  27 #include "buffer_tree.h"
  28 #include "write.h"
  29 #include "write_common.h"
  30 #include "alsa_write.cmdline.h"
  31 #include "error.h"
  32
  33 /** Data specific to the alsa writer. */
  34 struct private_alsa_write_data {
  35         /** The alsa handle */
  36         snd_pcm_t *handle;
  37         /** Determined and set by alsa_init(). */
  38         int bytes_per_frame;
  39         /**
  40          * The sample rate given by command line option or the decoder
  41          * of the writer node group.
  42          */
  43         unsigned sample_rate;
  44         snd_pcm_format_t sample_format;
  45         /**
  46          * The number of channels, given by command line option or the
  47          * decoder of the writer node group.
  48          */
  49         unsigned channels;
  50         struct timeval drain_barrier;
  51         /* File descriptor for select(). */
  52         int poll_fd;
  53 };
  54
  55 static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf)
  56 {
  57         switch (sf) {
  58         case SF_S8: return SND_PCM_FORMAT_S8;
  59         case SF_U8: return SND_PCM_FORMAT_U8;
  60         case SF_S16_LE: return SND_PCM_FORMAT_S16_LE;
  61         case SF_S16_BE: return SND_PCM_FORMAT_S16_BE;
  62         case SF_U16_LE: return SND_PCM_FORMAT_U16_LE;
  63         case SF_U16_BE: return SND_PCM_FORMAT_U16_BE;
  64         default: return SND_PCM_FORMAT_S16_LE;
  65         }
  66 }
  67
  68 /* Install PCM software and hardware configuration. */
  69 static int alsa_init(struct private_alsa_write_data *pad,
  70                 struct alsa_write_args_info *conf)
  71 {
  72         snd_pcm_hw_params_t *hwparams;
  73         snd_pcm_sw_params_t *swparams;
  74         snd_pcm_uframes_t start_threshold, stop_threshold;
  75         snd_pcm_uframes_t buffer_size, period_size;
  76         snd_output_t *log;
  77         unsigned buffer_time;
  78         int err;
  79
  80         PARA_INFO_LOG("opening %s\n", conf->device_arg);
  81         err = snd_pcm_open(&pad->handle, conf->device_arg,
  82                 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  83         if (err < 0)
  84                 return -E_PCM_OPEN;
  85
  86         snd_pcm_hw_params_alloca(&hwparams);
  87         snd_pcm_sw_params_alloca(&swparams);
  88         if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
  89                 return -E_BROKEN_CONF;
  90         if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
  91                         SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
  92                 return -E_ACCESS_TYPE;
  93         if (snd_pcm_hw_params_set_format(pad->handle, hwparams,
  94                         pad->sample_format) < 0)
  95                 return -E_SAMPLE_FORMAT;
  96         if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
  97                         pad->channels) < 0)
  98                 return -E_CHANNEL_COUNT;
  99         if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
 100                         &pad->sample_rate, NULL) < 0)
 101                 return -E_SET_RATE;
 102         err = snd_pcm_hw_params_get_buffer_time_max(hwparams,
 103                 &buffer_time, NULL);
 104         if (err < 0 || buffer_time == 0)
 105                 return -E_GET_BUFFER_TIME;
 106         if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
 107                         &buffer_time, NULL) < 0)
 108                 return -E_SET_BUFFER_TIME;
 109         if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
 110                 return -E_HW_PARAMS;
 111         snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
 112         snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
 113         if (period_size == buffer_size)
 114                 return -E_BAD_PERIOD;
 115         /* software parameter setup */
 116         snd_pcm_sw_params_current(pad->handle, swparams);
 117         snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
 118         if (buffer_size < 1)
 119                 start_threshold = 1;
 120         else
 121                 start_threshold = PARA_MIN(buffer_size,
 122                         (snd_pcm_uframes_t)pad->sample_rate);
 123         if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 124                         start_threshold) < 0)
 125                 return -E_START_THRESHOLD;
 126         stop_threshold = buffer_size;
 127         if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 128                         stop_threshold) < 0)
 129                 return -E_STOP_THRESHOLD;
 130         if (snd_pcm_sw_params(pad->handle, swparams) < 0)
 131                 PARA_WARNING_LOG("unable to install sw params\n");
 132         pad->bytes_per_frame = snd_pcm_format_physical_width(pad->sample_format)
 133                 * pad->channels / 8;
 134         if (pad->bytes_per_frame <= 0)
 135                 return -E_PHYSICAL_WIDTH;
 136         if (snd_pcm_nonblock(pad->handle, 1))
 137                 PARA_ERROR_LOG("failed to set nonblock mode\n");
 138         err = snd_output_buffer_open(&log);
 139         if (err == 0) {
 140                 char *buf;
 141                 PARA_INFO_LOG("dumping alsa configuration\n");
 142                 snd_pcm_dump(pad->handle, log);
 143                 snd_output_buffer_string(log, &buf);
 144                 for (;;) {
 145                         char *p = strchr(buf, '\n');
 146                         if (!p) /* omit last output line, it's empty */
 147                                 break;
 148                         *p = '\0';
 149                         PARA_INFO_LOG("%s\n", buf);
 150                         buf = p + 1;
 151                 }
 152                 snd_output_close(log);
 153         }
 154         return 1;
 155 }
 156
 157 static void alsa_write_pre_select(struct sched *s, struct task *t)
 158 {
 159         struct pollfd pfd;
 160         struct writer_node *wn = container_of(t, struct writer_node, task);
 161         struct private_alsa_write_data *pad = wn->private_data;
 162         int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
 163
 164         if (pad)
 165                 pad->poll_fd = -1;
 166         if (ret == 0)
 167                 return;
 168         if (!pad) {
 169                 sched_min_delay(s);
 170                 return;
 171         }
 172         if (ret < 0) {
 173                 sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
 174                 return;
 175         }
 176         ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
 177         if (ret < 0) {
 178                 PARA_ERROR_LOG("%s\n", snd_strerror(-ret));
 179                 t->error = -E_ALSA_POLL_FDS;
 180                 return;
 181         }
 182         pad->poll_fd = pfd.fd;
 183         para_fd_set(pfd.fd, &s->rfds, &s->max_fileno);
 184 }
 185
 186 static void alsa_close(struct writer_node *wn)
 187 {
 188         struct private_alsa_write_data *pad = wn->private_data;
 189         PARA_INFO_LOG("closing writer node %p\n", wn);
 190
 191         if (!pad)
 192                 return;
 193         /*
 194          * It's OK to have a blocking operation here because we already made
 195          * sure that the PCM output buffer is (nearly) empty.
 196          */
 197         snd_pcm_nonblock(pad->handle, 0);
 198         snd_pcm_drain(pad->handle);
 199         snd_pcm_close(pad->handle);
 200         snd_config_update_free_global();
 201         free(pad);
 202 }
 203
 204 static void alsa_write_post_select(__a_unused struct sched *s,
 205                 struct task *t)
 206 {
 207         struct writer_node *wn = container_of(t, struct writer_node, task);
 208         struct private_alsa_write_data *pad = wn->private_data;
 209         struct btr_node *btrn = wn->btrn;
 210         char *data;
 211         size_t bytes;
 212         snd_pcm_sframes_t frames;
 213         int ret;
 214
 215 again:
 216         t->error = 0;
 217         ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 218         if (ret == 0)
 219                 return;
 220         btr_merge(btrn, wn->min_iqs);
 221         bytes = btr_next_buffer(btrn, &data);
 222         if (ret < 0 || bytes < wn->min_iqs) { /* eof */
 223                 assert(btr_no_parent(btrn));
 224                 ret = -E_WRITE_COMMON_EOF;
 225                 if (!pad)
 226                         goto err;
 227                 /* wait until pending frames are played */
 228                 if (pad->drain_barrier.tv_sec == 0) {
 229                         PARA_DEBUG_LOG("waiting for device to drain\n");
 230                         tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
 231                                 &pad->drain_barrier);
 232                         return;
 233                 }
 234                 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
 235                         goto err;
 236                 return;
 237         }
 238         if (!pad) {
 239                 int32_t val;
 240
 241                 if (bytes == 0) /* no data available */
 242                         return;
 243                 pad = para_calloc(sizeof(*pad));
 244                 get_btr_sample_rate(btrn, &val);
 245                 pad->sample_rate = val;
 246                 get_btr_channels(btrn, &val);
 247                 pad->channels = val;
 248                 get_btr_sample_format(btrn, &val);
 249                 pad->sample_format = get_alsa_pcm_format(val);
 250
 251                 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
 252                         pad->sample_rate);
 253                 ret = alsa_init(pad, wn->conf);
 254                 if (ret < 0) {
 255                         free(pad);
 256                         goto err;
 257                 }
 258                 wn->private_data = pad;
 259                 wn->min_iqs = pad->bytes_per_frame;
 260                 goto again;
 261         }
 262         if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds))
 263                 return;
 264         frames = bytes / pad->bytes_per_frame;
 265         frames = snd_pcm_writei(pad->handle, data, frames);
 266         if (frames == 0 || frames == -EAGAIN) {
 267                 /*
 268                  * The alsa poll fd was ready for IO but we failed to write to
 269                  * the alsa handle. This means another event is pending. We
 270                  * don't care about that but we have to dispatch the event in
 271                  * order to avoid a busy loop. So we simply read from the poll
 272                  * fd.
 273                  */
 274                 char buf[100];
 275                 if (read(pad->poll_fd, buf, 100))
 276                         do_nothing;
 277                 return;
 278         }
 279         if (frames > 0) {
 280                 btr_consume(btrn, frames * pad->bytes_per_frame);
 281                 goto again;
 282         }
 283         if (frames == -EPIPE) {
 284                 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
 285                 snd_pcm_prepare(pad->handle);
 286                 return;
 287         }
 288         PARA_WARNING_LOG("%s\n", snd_strerror(-frames));
 289         ret = -E_ALSA_WRITE;
 290 err:
 291         assert(ret < 0);
 292         btr_remove_node(btrn);
 293         t->error = ret;
 294 }
 295
 296 __malloc static void *alsa_parse_config_or_die(const char *options)
 297 {
 298         struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
 299
 300         /* exits on errors */
 301         alsa_cmdline_parser_string(options, conf, "alsa_write");
 302         return conf;
 303 }
 304
 305 static void alsa_free_config(void *conf)
 306 {
 307         alsa_cmdline_parser_free(conf);
 308 }
 309
 310 /**
 311  * The init function of the alsa writer.
 312  *
 313  * \param w Pointer to the writer to initialize.
 314  *
 315  * \sa struct \ref writer.
 316  */
 317 void alsa_write_init(struct writer *w)
 318 {
 319         struct alsa_write_args_info dummy;
 320
 321         alsa_cmdline_parser_init(&dummy);
 322         w->close = alsa_close;
 323         w->pre_select = alsa_write_pre_select;
 324         w->post_select = alsa_write_post_select;
 325         w->parse_config_or_die = alsa_parse_config_or_die;
 326         w->shutdown = NULL; /* nothing to do */
 327         w->free_config = alsa_free_config;
 328         w->help = (struct ggo_help) {
 329                 .short_help = alsa_write_args_info_help,
 330                 .detailed_help = alsa_write_args_info_detailed_help
 331         };
 332         alsa_cmdline_parser_free(&dummy);
 333 }