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 int32_t hwcaps[] = {
  31         SR_CONF_SAMPLERATE,
  32         SR_CONF_LIMIT_SAMPLES,
  33         SR_CONF_CONTINUOUS,
  34 };
  35
  36 SR_PRIV struct sr_dev_driver alsa_driver_info;
  37 static struct sr_dev_driver *di = &alsa_driver_info;
  38
  39 static void clear_helper(void *priv)
  40 {
  41         struct dev_context *devc;
  42
  43         devc = priv;
  44
  45         snd_pcm_hw_params_free(devc->hw_params);
  46         devc->hw_params = NULL;
  47
  48         g_free((void *)devc->samplerates);
  49         devc->samplerates = NULL;
  50 }
  51
  52 static int dev_clear(void)
  53 {
  54         return std_dev_clear(di, clear_helper);
  55 }
  56
  57 static int init(struct sr_context *sr_ctx)
  58 {
  59         return std_init(sr_ctx, di, LOG_PREFIX);
  60 }
  61
  62 static GSList *scan(GSList *options)
  63 {
  64         return alsa_scan(options, di);
  65 }
  66
  67 static GSList *dev_list(void)
  68 {
  69         return ((struct drv_context *)(di->priv))->instances;
  70 }
  71
  72 static int dev_open(struct sr_dev_inst *sdi)
  73 {
  74         struct dev_context *devc;
  75         int ret;
  76
  77         devc = sdi->priv;
  78
  79         if (!(devc->hwdev)) {
  80                 sr_err("devc->hwdev was NULL.");
  81                 return SR_ERR_BUG;
  82         }
  83
  84         sr_dbg("Opening audio device '%s' for stream capture.", devc->hwdev);
  85         ret = snd_pcm_open(&devc->capture_handle, devc->hwdev,
  86                            SND_PCM_STREAM_CAPTURE, 0);
  87         if (ret < 0) {
  88                 sr_err("Can't open audio device: %s.", snd_strerror(ret));
  89                 return SR_ERR;
  90         }
  91
  92         sr_dbg("Initializing hardware parameter structure.");
  93         ret = snd_pcm_hw_params_any(devc->capture_handle, devc->hw_params);
  94         if (ret < 0) {
  95                 sr_err("Can't initialize hardware parameter structure: %s.",
  96                        snd_strerror(ret));
  97                 return SR_ERR;
  98         }
  99
 100         sdi->status = SR_ST_ACTIVE;
 101
 102         return SR_OK;
 103 }
 104
 105 static int dev_close(struct sr_dev_inst *sdi)
 106 {
 107         int ret;
 108         struct dev_context *devc;
 109
 110         devc = sdi->priv;
 111
 112         if (devc->capture_handle) {
 113                 sr_dbg("Closing PCM device.");
 114                 if ((ret = snd_pcm_close(devc->capture_handle)) < 0)
 115                         sr_err("Failed to close device: %s.",
 116                                snd_strerror(ret));
 117                 devc->capture_handle = NULL;
 118                 sdi->status = SR_ST_INACTIVE;
 119         } else {
 120                 sr_dbg("No capture handle, no need to close audio device.");
 121         }
 122
 123         return SR_OK;
 124 }
 125
 126 static int cleanup(void)
 127 {
 128         return dev_clear();
 129 }
 130
 131 static int config_get(int id, GVariant **data, const struct sr_dev_inst *sdi,
 132                 const struct sr_channel_group *cg)
 133 {
 134         struct dev_context *devc;
 135
 136         (void)cg;
 137
 138         switch (id) {
 139         case SR_CONF_SAMPLERATE:
 140                 devc = sdi->priv;
 141                 *data = g_variant_new_uint64(devc->cur_samplerate);
 142                 break;
 143         default:
 144                 return SR_ERR_NA;
 145         }
 146
 147         return SR_OK;
 148 }
 149
 150 static int config_set(int id, GVariant *data, const struct sr_dev_inst *sdi,
 151                 const struct sr_channel_group *cg)
 152 {
 153         struct dev_context *devc;
 154
 155         (void)cg;
 156
 157         if (sdi->status != SR_ST_ACTIVE)
 158                 return SR_ERR_DEV_CLOSED;
 159
 160         devc = sdi->priv;
 161
 162         switch (id) {
 163         case SR_CONF_SAMPLERATE:
 164                 alsa_set_samplerate(sdi, g_variant_get_uint64(data));
 165                 break;
 166         case SR_CONF_LIMIT_SAMPLES:
 167                 devc->limit_samples = g_variant_get_uint64(data);
 168                 break;
 169         default:
 170                 return SR_ERR_NA;
 171         }
 172
 173         return SR_OK;
 174 }
 175
 176 static int config_list(int key, GVariant **data, const struct sr_dev_inst *sdi,
 177                 const struct sr_channel_group *cg)
 178 {
 179         struct dev_context *devc;
 180         GVariant *gvar;
 181         GVariantBuilder gvb;
 182         int i;
 183
 184         (void)cg;
 185
 186         switch (key) {
 187         case SR_CONF_DEVICE_OPTIONS:
 188                 *data = g_variant_new_fixed_array(G_VARIANT_TYPE_INT32,
 189                                 hwcaps, ARRAY_SIZE(hwcaps), sizeof(int32_t));
 190                 break;
 191         case SR_CONF_SAMPLERATE:
 192                 if (!sdi || !sdi->priv)
 193                         return SR_ERR_ARG;
 194                 devc = sdi->priv;
 195                 if (!devc->samplerates) {
 196                         sr_err("Instance did not contain a samplerate list.");
 197                         return SR_ERR_ARG;
 198                 }
 199                 for (i = 0; devc->samplerates[i]; i++)
 200                         ;
 201                 g_variant_builder_init(&gvb, G_VARIANT_TYPE("a{sv}"));
 202                 gvar = g_variant_new_fixed_array(G_VARIANT_TYPE("t"),
 203                                 devc->samplerates, i, sizeof(uint64_t));
 204                 g_variant_builder_add(&gvb, "{sv}", "samplerates", gvar);
 205                 *data = g_variant_builder_end(&gvb);
 206                 break;
 207         default:
 208                 return SR_ERR_NA;
 209         }
 210
 211         return SR_OK;
 212 }
 213
 214 static int dev_acquisition_start(const struct sr_dev_inst *sdi, void *cb_data)
 215 {
 216         struct dev_context *devc;
 217         int count, ret;
 218         char *endianness;
 219
 220         if (sdi->status != SR_ST_ACTIVE)
 221                 return SR_ERR_DEV_CLOSED;
 222
 223         devc = sdi->priv;
 224         devc->cb_data = cb_data;
 225         devc->num_samples = 0;
 226
 227         sr_dbg("Setting audio access type to RW/interleaved.");
 228         ret = snd_pcm_hw_params_set_access(devc->capture_handle,
 229                         devc->hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
 230         if (ret < 0) {
 231                 sr_err("Can't set audio access type: %s.", snd_strerror(ret));
 232                 return SR_ERR;
 233         }
 234
 235         /* FIXME: Hardcoded for 16bits. */
 236         if (SND_PCM_FORMAT_S16 == SND_PCM_FORMAT_S16_LE)
 237                 endianness = "little endian";
 238         else
 239                 endianness = "big endian";
 240         sr_dbg("Setting audio sample format to signed 16bit (%s).", endianness);
 241         ret = snd_pcm_hw_params_set_format(devc->capture_handle,
 242                                            devc->hw_params,
 243                                            SND_PCM_FORMAT_S16);
 244         if (ret < 0) {
 245                 sr_err("Can't set audio sample format: %s.", snd_strerror(ret));
 246                 return SR_ERR;
 247         }
 248
 249         sr_dbg("Setting audio samplerate to %" PRIu64 "Hz.",
 250                devc->cur_samplerate);
 251         ret = snd_pcm_hw_params_set_rate(devc->capture_handle, devc->hw_params,
 252                                          (unsigned int)devc->cur_samplerate, 0);
 253         if (ret < 0) {
 254                 sr_err("Can't set audio sample rate: %s.", snd_strerror(ret));
 255                 return SR_ERR;
 256         }
 257
 258         sr_dbg("Setting audio channel count to %d.", devc->num_channels);
 259         ret = snd_pcm_hw_params_set_channels(devc->capture_handle,
 260                                              devc->hw_params, devc->num_channels);
 261         if (ret < 0) {
 262                 sr_err("Can't set channel count: %s.", snd_strerror(ret));
 263                 return SR_ERR;
 264         }
 265
 266         sr_dbg("Setting audio parameters.");
 267         ret = snd_pcm_hw_params(devc->capture_handle, devc->hw_params);
 268         if (ret < 0) {
 269                 sr_err("Can't set parameters: %s.", snd_strerror(ret));
 270                 return SR_ERR;
 271         }
 272
 273         sr_dbg("Preparing audio interface for use.");
 274         ret = snd_pcm_prepare(devc->capture_handle);
 275         if (ret < 0) {
 276                 sr_err("Can't prepare audio interface for use: %s.",
 277                        snd_strerror(ret));
 278                 return SR_ERR;
 279         }
 280
 281         count = snd_pcm_poll_descriptors_count(devc->capture_handle);
 282         if (count < 1) {
 283                 sr_err("Unable to obtain poll descriptors count.");
 284                 return SR_ERR;
 285         }
 286
 287         if (!(devc->ufds = g_try_malloc(count * sizeof(struct pollfd)))) {
 288                 sr_err("Failed to malloc ufds.");
 289                 return SR_ERR_MALLOC;
 290         }
 291
 292         sr_spew("Getting %d poll descriptors.", count);
 293         ret = snd_pcm_poll_descriptors(devc->capture_handle, devc->ufds, count);
 294         if (ret < 0) {
 295                 sr_err("Unable to obtain poll descriptors: %s.",
 296                        snd_strerror(ret));
 297                 g_free(devc->ufds);
 298                 return SR_ERR;
 299         }
 300
 301         /* Send header packet to the session bus. */
 302         std_session_send_df_header(cb_data, LOG_PREFIX);
 303
 304         /* Poll every 10ms, or whenever some data comes in. */
 305         sr_source_add(devc->ufds[0].fd, devc->ufds[0].events, 10,
 306                       alsa_receive_data, (void *)sdi);
 307
 308         // g_free(devc->ufds); /* FIXME */
 309
 310         return SR_OK;
 311 }
 312
 313 static int dev_acquisition_stop(struct sr_dev_inst *sdi, void *cb_data)
 314 {
 315         struct sr_datafeed_packet packet;
 316         struct dev_context *devc;
 317
 318         devc = sdi->priv;
 319         devc->cb_data = cb_data;
 320
 321         sr_source_remove(devc->ufds[0].fd);
 322
 323         /* Send end packet to the session bus. */
 324         sr_dbg("Sending SR_DF_END packet.");
 325         packet.type = SR_DF_END;
 326         sr_session_send(cb_data, &packet);
 327
 328         return SR_OK;
 329 }
 330
 331 SR_PRIV struct sr_dev_driver alsa_driver_info = {
 332         .name = "alsa",
 333         .longname = "ALSA driver",
 334         .api_version = 1,
 335         .init = init,
 336         .cleanup = cleanup,
 337         .scan = scan,
 338         .dev_list = dev_list,
 339         .dev_clear = dev_clear,
 340         .config_get = config_get,
 341         .config_set = config_set,
 342         .config_list = config_list,
 343         .dev_open = dev_open,
 344         .dev_close = dev_close,
 345         .dev_acquisition_start = dev_acquisition_start,
 346         .dev_acquisition_stop = dev_acquisition_stop,
 347         .priv = NULL,
 348 };