hardware/alsa/api.c

   1 /*
   2  * This file is part of the libsigrok project.
   3  *
   4  * Copyright (C) 2011 Daniel Ribeiro <drwyrm@gmail.com>
   5  * Copyright (C) 2012 Uwe Hermann <uwe@hermann-uwe.de>
   6  * Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@gmail.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  21  */
  22
  23 #include <stdlib.h>
  24 #include <unistd.h>
  25 #include <string.h>
  26 #include "libsigrok.h"
  27 #include "libsigrok-internal.h"
  28 #include "protocol.h"
  29
  30 static const int hwcaps[] = {
  31         SR_CONF_SAMPLERATE,
  32         SR_CONF_LIMIT_SAMPLES,
  33         SR_CONF_CONTINUOUS,
  34         0,
  35 };
  36
  37 SR_PRIV struct sr_dev_driver alsa_driver_info;
  38 static struct sr_dev_driver *di = &alsa_driver_info;
  39
  40 static int clear_instances(void)
  41 {
  42         struct drv_context *drvc;
  43
  44         if (!(drvc = di->priv))
  45                 return SR_OK;
  46
  47         g_slist_free_full(drvc->instances, (GDestroyNotify)alsa_dev_inst_clear);
  48         drvc->instances = NULL;
  49
  50         return SR_OK;
  51 }
  52
  53 static int hw_init(struct sr_context *sr_ctx)
  54 {
  55         return std_hw_init(sr_ctx, di, DRIVER_LOG_DOMAIN);
  56 }
  57
  58 static GSList *hw_scan(GSList *options)
  59 {
  60         return alsa_scan(options, di);
  61 }
  62
  63 static GSList *hw_dev_list(void)
  64 {
  65         return ((struct drv_context *)(di->priv))->instances;
  66 }
  67
  68 static int hw_dev_open(struct sr_dev_inst *sdi)
  69 {
  70         struct dev_context *devc;
  71         int ret;
  72
  73         devc = sdi->priv;
  74
  75         if (!(devc->hwdev)) {
  76                 sr_err("devc->hwdev was NULL.");
  77                 return SR_ERR_BUG;
  78         }
  79
  80         sr_dbg("Opening audio device '%s' for stream capture.", devc->hwdev);
  81         ret = snd_pcm_open(&devc->capture_handle, devc->hwdev,
  82                            SND_PCM_STREAM_CAPTURE, 0);
  83         if (ret < 0) {
  84                 sr_err("Can't open audio device: %s.", snd_strerror(ret));
  85                 return SR_ERR;
  86         }
  87
  88         sr_dbg("Initializing hardware parameter structure.");
  89         ret = snd_pcm_hw_params_any(devc->capture_handle, devc->hw_params);
  90         if (ret < 0) {
  91                 sr_err("Can't initialize hardware parameter structure: %s.",
  92                        snd_strerror(ret));
  93                 return SR_ERR;
  94         }
  95
  96         return SR_OK;
  97 }
  98
  99 static int hw_dev_close(struct sr_dev_inst *sdi)
 100 {
 101         int ret;
 102         struct dev_context *devc;
 103
 104         devc = sdi->priv;
 105
 106         if (devc->capture_handle) {
 107                 sr_dbg("Closing PCM device.");
 108                 if ((ret = snd_pcm_close(devc->capture_handle)) < 0) {
 109                         sr_err("Failed to close device: %s.",
 110                                snd_strerror(ret));
 111                         devc->capture_handle = NULL;
 112                 }
 113         } else {
 114                 sr_dbg("No capture handle, no need to close audio device.");
 115         }
 116
 117         return SR_OK;
 118 }
 119
 120 static int hw_cleanup(void)
 121 {
 122         clear_instances();
 123
 124         return SR_OK;
 125 }
 126
 127 static int config_get(int id, const void **data, const struct sr_dev_inst *sdi)
 128 {
 129         struct dev_context *devc;
 130
 131         switch (id) {
 132         case SR_CONF_SAMPLERATE:
 133                 devc = sdi->priv;
 134                 *data = &devc->cur_samplerate;
 135                 break;
 136         default:
 137                 return SR_ERR_ARG;
 138         }
 139
 140         return SR_OK;
 141 }
 142
 143 static int config_set(int id, const void *value, const struct sr_dev_inst *sdi)
 144 {
 145         struct dev_context *devc;
 146
 147         devc = sdi->priv;
 148
 149         switch (id) {
 150         case SR_CONF_SAMPLERATE:
 151                 alsa_set_samplerate(sdi, *(const uint64_t *)value);
 152                 break;
 153         case SR_CONF_LIMIT_SAMPLES:
 154                 devc->limit_samples = *(const uint64_t *)value;
 155                 break;
 156         default:
 157                 sr_err("Unknown capability: %d.", id);
 158                 return SR_ERR;
 159         }
 160
 161         return SR_OK;
 162 }
 163
 164 static int config_list(int key, const void **data, const struct sr_dev_inst *sdi)
 165 {
 166         struct dev_context *devc;
 167
 168         (void)sdi;
 169
 170         switch (key) {
 171         case SR_CONF_DEVICE_OPTIONS:
 172                 *data = hwcaps;
 173                 break;
 174         case SR_CONF_SAMPLERATE:
 175                 if (!sdi || !sdi->priv)
 176                         return SR_ERR_ARG;
 177                 devc = sdi->priv;
 178                 if (!devc->supp_rates.list) {
 179                         sr_err("Instance did not contain a samplerate list.");
 180                         return SR_ERR_ARG;
 181                 }
 182                 *data = &devc->supp_rates;
 183                 break;
 184         default:
 185                 return SR_ERR_ARG;
 186         }
 187
 188         return SR_OK;
 189 }
 190
 191 static int hw_dev_acquisition_start(const struct sr_dev_inst *sdi,
 192                                     void *cb_data)
 193 {
 194         struct dev_context *devc;
 195         int count, ret;
 196         char *endianness;
 197
 198         devc = sdi->priv;
 199         devc->cb_data = cb_data;
 200         devc->num_samples = 0;
 201
 202         sr_dbg("Setting audio access type to RW/interleaved.");
 203         ret = snd_pcm_hw_params_set_access(devc->capture_handle,
 204                         devc->hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
 205         if (ret < 0) {
 206                 sr_err("Can't set audio access type: %s.", snd_strerror(ret));
 207                 return SR_ERR;
 208         }
 209
 210         /* FIXME: Hardcoded for 16bits. */
 211         if (SND_PCM_FORMAT_S16 == SND_PCM_FORMAT_S16_LE)
 212                 endianness = "little endian";
 213         else
 214                 endianness = "big endian";
 215         sr_dbg("Setting audio sample format to signed 16bit (%s).", endianness);
 216         ret = snd_pcm_hw_params_set_format(devc->capture_handle,
 217                                            devc->hw_params,
 218                                            SND_PCM_FORMAT_S16);
 219         if (ret < 0) {
 220                 sr_err("Can't set audio sample format: %s.", snd_strerror(ret));
 221                 return SR_ERR;
 222         }
 223
 224         sr_dbg("Setting audio samplerate to %" PRIu64 "Hz.",
 225                devc->cur_samplerate);
 226         ret = snd_pcm_hw_params_set_rate(devc->capture_handle, devc->hw_params,
 227                                          (unsigned int)devc->cur_samplerate, 0);
 228         if (ret < 0) {
 229                 sr_err("Can't set audio sample rate: %s.", snd_strerror(ret));
 230                 return SR_ERR;
 231         }
 232
 233         sr_dbg("Setting audio channel count to %d.", devc->num_probes);
 234         ret = snd_pcm_hw_params_set_channels(devc->capture_handle,
 235                                              devc->hw_params, devc->num_probes);
 236         if (ret < 0) {
 237                 sr_err("Can't set channel count: %s.", snd_strerror(ret));
 238                 return SR_ERR;
 239         }
 240
 241         sr_dbg("Setting audio parameters.");
 242         ret = snd_pcm_hw_params(devc->capture_handle, devc->hw_params);
 243         if (ret < 0) {
 244                 sr_err("Can't set parameters: %s.", snd_strerror(ret));
 245                 return SR_ERR;
 246         }
 247
 248         sr_dbg("Preparing audio interface for use.");
 249         ret = snd_pcm_prepare(devc->capture_handle);
 250         if (ret < 0) {
 251                 sr_err("Can't prepare audio interface for use: %s.",
 252                        snd_strerror(ret));
 253                 return SR_ERR;
 254         }
 255
 256         count = snd_pcm_poll_descriptors_count(devc->capture_handle);
 257         if (count < 1) {
 258                 sr_err("Unable to obtain poll descriptors count.");
 259                 return SR_ERR;
 260         }
 261
 262         if (!(devc->ufds = g_try_malloc(count * sizeof(struct pollfd)))) {
 263                 sr_err("Failed to malloc ufds.");
 264                 return SR_ERR_MALLOC;
 265         }
 266
 267         sr_spew("Getting %d poll descriptors.", count);
 268         ret = snd_pcm_poll_descriptors(devc->capture_handle, devc->ufds, count);
 269         if (ret < 0) {
 270                 sr_err("Unable to obtain poll descriptors: %s.",
 271                        snd_strerror(ret));
 272                 g_free(devc->ufds);
 273                 return SR_ERR;
 274         }
 275
 276         /* Send header packet to the session bus. */
 277         std_session_send_df_header(cb_data, DRIVER_LOG_DOMAIN);
 278
 279         /* Poll every 10ms, or whenever some data comes in. */
 280         sr_source_add(devc->ufds[0].fd, devc->ufds[0].events, 10,
 281                       alsa_receive_data, (void *)sdi);
 282
 283         // g_free(devc->ufds); /* FIXME */
 284
 285         return SR_OK;
 286 }
 287
 288 static int hw_dev_acquisition_stop(struct sr_dev_inst *sdi, void *cb_data)
 289 {
 290         struct sr_datafeed_packet packet;
 291         struct dev_context *devc;
 292
 293         devc = sdi->priv;
 294         devc->cb_data = cb_data;
 295
 296         sr_source_remove(devc->ufds[0].fd);
 297
 298         /* Send end packet to the session bus. */
 299         sr_dbg("Sending SR_DF_END packet.");
 300         packet.type = SR_DF_END;
 301         sr_session_send(cb_data, &packet);
 302
 303         return SR_OK;
 304 }
 305
 306 SR_PRIV struct sr_dev_driver alsa_driver_info = {
 307         .name = "alsa",
 308         .longname = "ALSA driver",
 309         .api_version = 1,
 310         .init = hw_init,
 311         .cleanup = hw_cleanup,
 312         .scan = hw_scan,
 313         .dev_list = hw_dev_list,
 314         .dev_clear = clear_instances,
 315         .config_get = config_get,
 316         .config_set = config_set,
 317         .config_list = config_list,
 318         .dev_open = hw_dev_open,
 319         .dev_close = hw_dev_close,
 320         .dev_acquisition_start = hw_dev_acquisition_start,
 321         .dev_acquisition_stop = hw_dev_acquisition_stop,
 322         .priv = NULL,
 323 };