hardware/alsa/alsa.c

   1 /*
   2  * This file is part of the sigrok project.
   3  *
   4  * Copyright (C) 2011 Daniel Ribeiro <drwyrm@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #include "config.h" /* Must come before sigrok.h */
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include <string.h>
  25 #include <sigrok.h>
  26 #include <sigrok-internal.h>
  27 #include <alsa/asoundlib.h>
  28
  29 #define NUM_PROBES 2
  30 #define SAMPLE_WIDTH 16
  31 #define AUDIO_DEV "plughw:0,0"
  32
  33 static int capabilities[] = {
  34         SR_HWCAP_SAMPLERATE,
  35         SR_HWCAP_LIMIT_SAMPLES,
  36         SR_HWCAP_CONTINUOUS,
  37 };
  38
  39 static GSList *device_instances = NULL;
  40
  41 struct alsa {
  42         uint64_t cur_rate;
  43         uint64_t limit_samples;
  44         snd_pcm_t *capture_handle;
  45         snd_pcm_hw_params_t *hw_params;
  46         gpointer session_id;
  47 };
  48
  49 static int hw_init(const char *deviceinfo)
  50 {
  51         struct sr_device_instance *sdi;
  52         struct alsa *alsa;
  53
  54         /* Avoid compiler warnings. */
  55         deviceinfo = deviceinfo;
  56
  57         if (!(alsa = g_try_malloc0(sizeof(struct alsa)))) {
  58                 sr_err("alsa: %s: alsa malloc failed", __func__);
  59                 return 0;
  60         }
  61
  62         sdi = sr_device_instance_new(0, SR_ST_ACTIVE, "alsa", NULL, NULL);
  63         if (!sdi)
  64                 goto free_alsa;
  65
  66         sdi->priv = alsa;
  67
  68         device_instances = g_slist_append(device_instances, sdi);
  69
  70         return 1;
  71 free_alsa:
  72         g_free(alsa);
  73         return 0;
  74 }
  75
  76 static int hw_opendev(int device_index)
  77 {
  78         struct sr_device_instance *sdi;
  79         struct alsa *alsa;
  80         int err;
  81
  82         if (!(sdi = sr_get_device_instance(device_instances, device_index)))
  83                 return SR_ERR;
  84         alsa = sdi->priv;
  85
  86         err = snd_pcm_open(&alsa->capture_handle, AUDIO_DEV,
  87                                         SND_PCM_STREAM_CAPTURE, 0);
  88         if (err < 0) {
  89                 sr_warn("cannot open audio device %s (%s)", AUDIO_DEV,
  90                         snd_strerror(err));
  91                 return SR_ERR;
  92         }
  93
  94         err = snd_pcm_hw_params_malloc(&alsa->hw_params);
  95         if (err < 0) {
  96                 sr_warn("cannot allocate hardware parameter structure (%s)",
  97                         snd_strerror(err));
  98                 return SR_ERR;
  99         }
 100
 101         err = snd_pcm_hw_params_any(alsa->capture_handle, alsa->hw_params);
 102         if (err < 0) {
 103                 sr_warn("cannot initialize hardware parameter structure (%s)",
 104                                 snd_strerror(err));
 105                 return SR_ERR;
 106         }
 107
 108         return SR_OK;
 109 }
 110
 111 static void hw_closedev(int device_index)
 112 {
 113         struct sr_device_instance *sdi;
 114         struct alsa *alsa;
 115
 116         if (!(sdi = sr_get_device_instance(device_instances, device_index)))
 117                 return;
 118         alsa = sdi->priv;
 119         if (!alsa)
 120                 return;
 121
 122         if (alsa->hw_params)
 123                 snd_pcm_hw_params_free(alsa->hw_params);
 124         if (alsa->capture_handle)
 125                 snd_pcm_close(alsa->capture_handle);
 126 }
 127
 128 static void hw_cleanup(void)
 129 {
 130         struct sr_device_instance *sdi;
 131
 132         if (!(sdi = sr_get_device_instance(device_instances, 0)))
 133                 return;
 134
 135         free(sdi->priv);
 136         sr_device_instance_free(sdi);
 137 }
 138
 139 static void *hw_get_device_info(int device_index, int device_info_id)
 140 {
 141         struct sr_device_instance *sdi;
 142         struct alsa *alsa;
 143         void *info = NULL;
 144
 145         if (!(sdi = sr_get_device_instance(device_instances, device_index)))
 146                 return NULL;
 147         alsa = sdi->priv;
 148
 149         switch (device_info_id) {
 150         case SR_DI_INSTANCE:
 151                 info = sdi;
 152                 break;
 153         case SR_DI_NUM_PROBES:
 154                 info = GINT_TO_POINTER(NUM_PROBES);
 155                 break;
 156         case SR_DI_CUR_SAMPLERATE:
 157                 info = &alsa->cur_rate;
 158                 break;
 159         // case SR_DI_PROBE_TYPE:
 160         //      info = GINT_TO_POINTER(SR_PROBE_TYPE_ANALOG);
 161         //      break;
 162         }
 163
 164         return info;
 165 }
 166
 167 static int hw_get_status(int device_index)
 168 {
 169         /* Avoid compiler warnings. */
 170         device_index = device_index;
 171
 172         return SR_ST_ACTIVE;
 173 }
 174
 175 static int *hw_get_capabilities(void)
 176 {
 177         return capabilities;
 178 }
 179
 180 static int hw_set_configuration(int device_index, int capability, void *value)
 181 {
 182         struct sr_device_instance *sdi;
 183         struct alsa *alsa;
 184
 185         if (!(sdi = sr_get_device_instance(device_instances, device_index)))
 186                 return SR_ERR;
 187         alsa = sdi->priv;
 188
 189         switch (capability) {
 190         case SR_HWCAP_PROBECONFIG:
 191                 return SR_OK;
 192         case SR_HWCAP_SAMPLERATE:
 193                 alsa->cur_rate = *(uint64_t *) value;
 194                 return SR_OK;
 195         case SR_HWCAP_LIMIT_SAMPLES:
 196                 alsa->limit_samples = *(uint64_t *) value;
 197                 return SR_OK;
 198         default:
 199                 return SR_ERR;
 200         }
 201 }
 202
 203 static int receive_data(int fd, int revents, void *user_data)
 204 {
 205         struct sr_device_instance *sdi = user_data;
 206         struct alsa *alsa = sdi->priv;
 207         struct sr_datafeed_packet packet;
 208         struct sr_analog_sample *sample;
 209         unsigned int sample_size = sizeof(struct sr_analog_sample) +
 210                 (NUM_PROBES * sizeof(struct sr_analog_probe));
 211         char *outb;
 212         char inb[4096];
 213         int i, x, count;
 214
 215         fd = fd;
 216         revents = revents;
 217
 218         do {
 219                 memset(inb, 0, sizeof(inb));
 220                 count = snd_pcm_readi(alsa->capture_handle, inb,
 221                         MIN(4096/4, alsa->limit_samples));
 222                 if (count < 1) {
 223                         sr_warn("Failed to read samples");
 224                         return FALSE;
 225                 }
 226
 227                 if (!(outb = g_try_malloc(sample_size * count))) {
 228                         sr_err("alsa: %s: outb malloc failed", __func__);
 229                         return FALSE;
 230                 }
 231
 232                 for (i = 0; i < count; i++) {
 233                         sample = (struct sr_analog_sample *)
 234                                                 (outb + (i * sample_size));
 235                         sample->num_probes = NUM_PROBES;
 236
 237                         for (x = 0; x < NUM_PROBES; x++) {
 238                                 sample->probes[x].val =
 239                                         *(uint16_t *) (inb + (i * 4) + (x * 2));
 240                                 sample->probes[x].val &= ((1 << 16) - 1);
 241                                 sample->probes[x].res = 16;
 242                         }
 243                 }
 244
 245                 packet.type = SR_DF_ANALOG;
 246                 packet.length = count * sample_size;
 247                 packet.unitsize = sample_size;
 248                 packet.payload = outb;
 249                 sr_session_bus(user_data, &packet);
 250                 g_free(outb);
 251                 alsa->limit_samples -= count;
 252
 253         } while (alsa->limit_samples > 0);
 254
 255         packet.type = SR_DF_END;
 256         sr_session_bus(user_data, &packet);
 257
 258         return TRUE;
 259 }
 260
 261 static int hw_start_acquisition(int device_index, gpointer session_device_id)
 262 {
 263         struct sr_device_instance *sdi;
 264         struct alsa *alsa;
 265         struct sr_datafeed_packet packet;
 266         struct sr_datafeed_header header;
 267         struct pollfd *ufds;
 268         int count;
 269         int err;
 270
 271         if (!(sdi = sr_get_device_instance(device_instances, device_index)))
 272                 return SR_ERR;
 273         alsa = sdi->priv;
 274
 275         err = snd_pcm_hw_params_set_access(alsa->capture_handle,
 276                         alsa->hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
 277         if (err < 0) {
 278                 sr_warn("cannot set access type (%s)", snd_strerror(err));
 279                 return SR_ERR;
 280         }
 281
 282         /* FIXME: Hardcoded for 16bits */
 283         err = snd_pcm_hw_params_set_format(alsa->capture_handle,
 284                         alsa->hw_params, SND_PCM_FORMAT_S16_LE);
 285         if (err < 0) {
 286                 sr_warn("cannot set sample format (%s)", snd_strerror(err));
 287                 return SR_ERR;
 288         }
 289
 290         err = snd_pcm_hw_params_set_rate_near(alsa->capture_handle,
 291                         alsa->hw_params, (unsigned int *) &alsa->cur_rate, 0);
 292         if (err < 0) {
 293                 sr_warn("cannot set sample rate (%s)", snd_strerror(err));
 294                 return SR_ERR;
 295         }
 296
 297         err = snd_pcm_hw_params_set_channels(alsa->capture_handle,
 298                         alsa->hw_params, NUM_PROBES);
 299         if (err < 0) {
 300                 sr_warn("cannot set channel count (%s)", snd_strerror(err));
 301                 return SR_ERR;
 302         }
 303
 304         err = snd_pcm_hw_params(alsa->capture_handle, alsa->hw_params);
 305         if (err < 0) {
 306                 sr_warn("cannot set parameters (%s)", snd_strerror(err));
 307                 return SR_ERR;
 308         }
 309
 310         err = snd_pcm_prepare(alsa->capture_handle);
 311         if (err < 0) {
 312                 sr_warn("cannot prepare audio interface for use (%s)",
 313                                 snd_strerror(err));
 314                 return SR_ERR;
 315         }
 316
 317         count = snd_pcm_poll_descriptors_count(alsa->capture_handle);
 318         if (count < 1) {
 319                 sr_warn("Unable to obtain poll descriptors count");
 320                 return SR_ERR;
 321         }
 322
 323         if (!(ufds = g_try_malloc(count * sizeof(struct pollfd)))) {
 324                 sr_warn("alsa: %s: ufds malloc failed", __func__);
 325                 return SR_ERR_MALLOC;
 326         }
 327
 328         err = snd_pcm_poll_descriptors(alsa->capture_handle, ufds, count);
 329         if (err < 0) {
 330                 sr_warn("Unable to obtain poll descriptors (%s)",
 331                                 snd_strerror(err));
 332                 g_free(ufds);
 333                 return SR_ERR;
 334         }
 335
 336         alsa->session_id = session_device_id;
 337         sr_source_add(ufds[0].fd, ufds[0].events, 10, receive_data, sdi);
 338
 339         packet.type = SR_DF_HEADER;
 340         packet.length = sizeof(struct sr_datafeed_header);
 341         packet.payload = (unsigned char *) &header;
 342         header.feed_version = 1;
 343         gettimeofday(&header.starttime, NULL);
 344         header.samplerate = alsa->cur_rate;
 345         header.num_analog_probes = NUM_PROBES;
 346         header.num_logic_probes = 0;
 347         header.protocol_id = SR_PROTO_RAW;
 348         sr_session_bus(session_device_id, &packet);
 349         g_free(ufds);
 350
 351         return SR_OK;
 352 }
 353
 354 static void hw_stop_acquisition(int device_index, gpointer session_device_id)
 355 {
 356         /* Avoid compiler warnings. */
 357         device_index = device_index;
 358         session_device_id = session_device_id;
 359 }
 360
 361 struct sr_device_plugin alsa_plugin_info = {
 362         .name = "alsa",
 363         .longname = "ALSA driver",
 364         .api_version = 1,
 365         .init = hw_init,
 366         .cleanup = hw_cleanup,
 367         .open = hw_opendev,
 368         .close = hw_closedev,
 369         .get_device_info = hw_get_device_info,
 370         .get_status = hw_get_status,
 371         .get_capabilities = hw_get_capabilities,
 372         .set_configuration = hw_set_configuration,
 373         .start_acquisition = hw_start_acquisition,
 374         .stop_acquisition = hw_stop_acquisition,
 375 };