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         /** The approximate maximum buffer duration in us. */
  40         unsigned buffer_time;
  41         /* Number of frames that fit into the buffer. */
  42         snd_pcm_uframes_t buffer_frames;
  43         /**
  44          * The sample rate given by command line option or the decoder
  45          * of the writer node group.
  46          */
  47         unsigned sample_rate;
  48         snd_pcm_format_t sample_format;
  49         /**
  50          * The number of channels, given by command line option or the
  51          * decoder of the writer node group.
  52          */
  53         unsigned channels;
  54         struct timeval drain_barrier;
  55         /* File descriptor for select(). */
  56         int poll_fd;
  57 };
  58
  59 static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf)
  60 {
  61         switch (sf) {
  62         case SF_S8: return SND_PCM_FORMAT_S8;
  63         case SF_U8: return SND_PCM_FORMAT_U8;
  64         case SF_S16_LE: return SND_PCM_FORMAT_S16_LE;
  65         case SF_S16_BE: return SND_PCM_FORMAT_S16_BE;
  66         case SF_U16_LE: return SND_PCM_FORMAT_U16_LE;
  67         case SF_U16_BE: return SND_PCM_FORMAT_U16_BE;
  68         default: return SND_PCM_FORMAT_S16_LE;
  69         }
  70 }
  71
  72 /* Install PCM software and hardware configuration. */
  73 static int alsa_init(struct private_alsa_write_data *pad,
  74                 struct alsa_write_args_info *conf)
  75 {
  76         snd_pcm_hw_params_t *hwparams;
  77         snd_pcm_sw_params_t *swparams;
  78         snd_pcm_uframes_t start_threshold, stop_threshold;
  79         snd_pcm_uframes_t period_size;
  80         snd_output_t *log;
  81         int err;
  82
  83         PARA_INFO_LOG("opening %s\n", conf->device_arg);
  84         err = snd_pcm_open(&pad->handle, conf->device_arg,
  85                 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  86         if (err < 0)
  87                 return -E_PCM_OPEN;
  88
  89         snd_pcm_hw_params_alloca(&hwparams);
  90         snd_pcm_sw_params_alloca(&swparams);
  91         if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
  92                 return -E_BROKEN_CONF;
  93         if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
  94                         SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
  95                 return -E_ACCESS_TYPE;
  96         if (snd_pcm_hw_params_set_format(pad->handle, hwparams,
  97                         pad->sample_format) < 0)
  98                 return -E_SAMPLE_FORMAT;
  99         if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
 100                         pad->channels) < 0)
 101                 return -E_CHANNEL_COUNT;
 102         if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
 103                         &pad->sample_rate, NULL) < 0)
 104                 return -E_SET_RATE;
 105         err = snd_pcm_hw_params_get_buffer_time_max(hwparams,
 106                 &pad->buffer_time, NULL);
 107         if (err < 0 || !pad->buffer_time)
 108                 return -E_GET_BUFFER_TIME;
 109         if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
 110                         &pad->buffer_time, NULL) < 0)
 111                 return -E_SET_BUFFER_TIME;
 112         if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
 113                 return -E_HW_PARAMS;
 114         snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
 115         snd_pcm_hw_params_get_buffer_size(hwparams, &pad->buffer_frames);
 116         if (period_size == pad->buffer_frames)
 117                 return -E_BAD_PERIOD;
 118         snd_pcm_sw_params_current(pad->handle, swparams);
 119         snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
 120         if (pad->buffer_frames < 1)
 121                 start_threshold = 1;
 122         else
 123                 start_threshold = PARA_MIN(pad->buffer_frames,
 124                         (snd_pcm_uframes_t)pad->sample_rate);
 125         if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
 126                         start_threshold) < 0)
 127                 return -E_START_THRESHOLD;
 128         stop_threshold = pad->buffer_frames;
 129         if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
 130                         stop_threshold) < 0)
 131                 return -E_STOP_THRESHOLD;
 132         if (snd_pcm_sw_params(pad->handle, swparams) < 0)
 133                 PARA_WARNING_LOG("unable to install sw params\n");
 134         pad->bytes_per_frame = snd_pcm_format_physical_width(pad->sample_format)
 135                 * pad->channels / 8;
 136         if (pad->bytes_per_frame <= 0)
 137                 return -E_PHYSICAL_WIDTH;
 138         if (snd_pcm_nonblock(pad->handle, 1))
 139                 PARA_ERROR_LOG("failed to set nonblock mode\n");
 140         err = snd_output_buffer_open(&log);
 141         if (err == 0) {
 142                 char *buf;
 143                 PARA_INFO_LOG("dumping alsa configuration\n");
 144                 snd_pcm_dump(pad->handle, log);
 145                 snd_output_buffer_string(log, &buf);
 146                 for (;;) {
 147                         char *p = strchr(buf, '\n');
 148                         if (!p) /* omit last output line, it's empty */
 149                                 break;
 150                         *p = '\0';
 151                         PARA_INFO_LOG("%s\n", buf);
 152                         buf = p + 1;
 153                 }
 154                 snd_output_close(log);
 155         }
 156         return 1;
 157 }
 158
 159 static void alsa_write_pre_select(struct sched *s, struct task *t)
 160 {
 161         struct pollfd pfd;
 162         struct writer_node *wn = container_of(t, struct writer_node, task);
 163         struct private_alsa_write_data *pad = wn->private_data;
 164         int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
 165
 166         if (pad)
 167                 pad->poll_fd = -1;
 168         if (ret == 0)
 169                 return;
 170         if (!pad) {
 171                 sched_min_delay(s);
 172                 return;
 173         }
 174         if (ret < 0) {
 175                 sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
 176                 return;
 177         }
 178         ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
 179         if (ret < 0) {
 180                 PARA_ERROR_LOG("%s\n", snd_strerror(-ret));
 181                 t->error = -E_ALSA_POLL_FDS;
 182                 return;
 183         }
 184         pad->poll_fd = pfd.fd;
 185         para_fd_set(pfd.fd, &s->rfds, &s->max_fileno);
 186 }
 187
 188 static void alsa_close(struct writer_node *wn)
 189 {
 190         struct private_alsa_write_data *pad = wn->private_data;
 191         PARA_INFO_LOG("closing writer node %p\n", wn);
 192
 193         if (!pad)
 194                 return;
 195         /*
 196          * It's OK to have a blocking operation here because we already made
 197          * sure that the PCM output buffer is (nearly) empty.
 198          */
 199         snd_pcm_nonblock(pad->handle, 0);
 200         snd_pcm_drain(pad->handle);
 201         snd_pcm_close(pad->handle);
 202         snd_config_update_free_global();
 203         free(pad);
 204 }
 205
 206 static void alsa_write_post_select(__a_unused struct sched *s,
 207                 struct task *t)
 208 {
 209         struct writer_node *wn = container_of(t, struct writer_node, task);
 210         struct private_alsa_write_data *pad = wn->private_data;
 211         struct btr_node *btrn = wn->btrn;
 212         char *data;
 213         size_t bytes;
 214         snd_pcm_sframes_t frames;
 215         int ret;
 216
 217 again:
 218         t->error = 0;
 219         ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
 220         if (ret == 0)
 221                 return;
 222         btr_merge(btrn, wn->min_iqs);
 223         bytes = btr_next_buffer(btrn, &data);
 224         if (ret < 0 || bytes < wn->min_iqs) { /* eof */
 225                 assert(btr_no_parent(btrn));
 226                 ret = -E_WRITE_COMMON_EOF;
 227                 if (!pad)
 228                         goto err;
 229                 /* wait until pending frames are played */
 230                 if (pad->drain_barrier.tv_sec == 0) {
 231                         PARA_DEBUG_LOG("waiting for device to drain\n");
 232                         tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
 233                                 &pad->drain_barrier);
 234                         return;
 235                 }
 236                 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
 237                         goto err;
 238                 return;
 239         }
 240         if (!pad) {
 241                 int32_t val;
 242
 243                 if (bytes == 0) /* no data available */
 244                         return;
 245                 pad = para_calloc(sizeof(*pad));
 246                 get_btr_sample_rate(btrn, &val);
 247                 pad->sample_rate = val;
 248                 get_btr_channels(btrn, &val);
 249                 pad->channels = val;
 250                 get_btr_sample_format(btrn, &val);
 251                 pad->sample_format = get_alsa_pcm_format(val);
 252
 253                 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
 254                         pad->sample_rate);
 255                 ret = alsa_init(pad, wn->conf);
 256                 if (ret < 0) {
 257                         free(pad);
 258                         goto err;
 259                 }
 260                 wn->private_data = pad;
 261                 wn->min_iqs = pad->bytes_per_frame;
 262                 goto again;
 263         }
 264         if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds))
 265                 return;
 266         frames = bytes / pad->bytes_per_frame;
 267         frames = snd_pcm_writei(pad->handle, data, frames);
 268         if (frames == 0 || frames == -EAGAIN) {
 269                 /*
 270                  * The alsa poll fd was ready for IO but we failed to write to
 271                  * the alsa handle. This means another event is pending. We
 272                  * don't care about that but we have to dispatch the event in
 273                  * order to avoid a busy loop. So we simply read from the poll
 274                  * fd.
 275                  */
 276                 char buf[100];
 277                 if (read(pad->poll_fd, buf, 100))
 278                         do_nothing;
 279                 return;
 280         }
 281         if (frames > 0) {
 282                 btr_consume(btrn, frames * pad->bytes_per_frame);
 283                 goto again;
 284         }
 285         if (frames == -EPIPE) {
 286                 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
 287                 snd_pcm_prepare(pad->handle);
 288                 return;
 289         }
 290         PARA_WARNING_LOG("%s\n", snd_strerror(-frames));
 291         ret = -E_ALSA_WRITE;
 292 err:
 293         assert(ret < 0);
 294         btr_remove_node(btrn);
 295         t->error = ret;
 296 }
 297
 298 __malloc static void *alsa_parse_config_or_die(const char *options)
 299 {
 300         struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
 301
 302         /* exits on errors */
 303         alsa_cmdline_parser_string(options, conf, "alsa_write");
 304         return conf;
 305 }
 306
 307 static void alsa_free_config(void *conf)
 308 {
 309         alsa_cmdline_parser_free(conf);
 310 }
 311
 312 /**
 313  * The init function of the alsa writer.
 314  *
 315  * \param w Pointer to the writer to initialize.
 316  *
 317  * \sa struct \ref writer.
 318  */
 319 void alsa_write_init(struct writer *w)
 320 {
 321         struct alsa_write_args_info dummy;
 322
 323         alsa_cmdline_parser_init(&dummy);
 324         w->close = alsa_close;
 325         w->pre_select = alsa_write_pre_select;
 326         w->post_select = alsa_write_post_select;
 327         w->parse_config_or_die = alsa_parse_config_or_die;
 328         w->shutdown = NULL; /* nothing to do */
 329         w->free_config = alsa_free_config;
 330         w->help = (struct ggo_help) {
 331                 .short_help = alsa_write_args_info_help,
 332                 .detailed_help = alsa_write_args_info_detailed_help
 333         };
 334         alsa_cmdline_parser_free(&dummy);
 335 }