libsigrok
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alsa.c
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00001 /*
00002  * This file is part of the sigrok project.
00003  *
00004  * Copyright (C) 2011 Daniel Ribeiro <drwyrm@gmail.com>
00005  *
00006  * This program is free software; you can redistribute it and/or modify
00007  * it under the terms of the GNU General Public License as published by
00008  * the Free Software Foundation; either version 2 of the License, or
00009  * (at your option) any later version.
00010  *
00011  * This program is distributed in the hope that it will be useful,
00012  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014  * GNU General Public License for more details.
00015  *
00016  * You should have received a copy of the GNU General Public License
00017  * along with this program; if not, write to the Free Software
00018  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
00019  */
00020 
00021 /* Note: This driver doesn't compile, analog support in sigrok is WIP. */
00022 
00023 #include <stdlib.h>
00024 #include <unistd.h>
00025 #include <string.h>
00026 #include <alsa/asoundlib.h>
00027 #include "sigrok.h"
00028 #include "sigrok-internal.h"
00029 
00030 #define NUM_PROBES 2
00031 #define SAMPLE_WIDTH 16
00032 #define AUDIO_DEV "plughw:0,0"
00033 
00034 struct sr_analog_probe {
00035         uint8_t att;
00036         uint8_t res;    /* Needs to be a power of 2, FIXME */
00037         uint16_t val;   /* Max hardware ADC width is 16bits */
00038 };
00039 
00040 struct sr_analog_sample {
00041         uint8_t num_probes; /* Max hardware probes is 256 */
00042         struct sr_analog_probe probes[];
00043 };
00044 
00045 static int hwcaps[] = {
00046         SR_HWCAP_SAMPLERATE,
00047         SR_HWCAP_LIMIT_SAMPLES,
00048         SR_HWCAP_CONTINUOUS,
00049 };
00050 
00051 /* TODO: Which probe names/numbers to use? */
00052 static const char *probe_names[NUM_PROBES + 1] = {
00053         "0",
00054         "1",
00055         NULL,
00056 };
00057 
00058 static GSList *dev_insts = NULL;
00059 
00060 /* Private, per-device-instance driver context. */
00061 struct context {
00062         uint64_t cur_rate;
00063         uint64_t limit_samples;
00064         snd_pcm_t *capture_handle;
00065         snd_pcm_hw_params_t *hw_params;
00066         void *session_dev_id;
00067 };
00068 
00069 static int hw_init(const char *devinfo)
00070 {
00071         struct sr_dev_inst *sdi;
00072         struct context *ctx;
00073 
00074         /* Avoid compiler warnings. */
00075         (void)devinfo;
00076 
00077         if (!(ctx = g_try_malloc0(sizeof(struct context)))) {
00078                 sr_err("alsa: %s: ctx malloc failed", __func__);
00079                 return 0;
00080         }
00081 
00082         if (!(sdi = sr_dev_inst_new(0, SR_ST_ACTIVE, "alsa", NULL, NULL))) {
00083                 sr_err("alsa: %s: sdi was NULL", __func__);
00084                 goto free_ctx;
00085         }
00086 
00087         sdi->priv = ctx;
00088 
00089         dev_insts = g_slist_append(dev_insts, sdi);
00090 
00091         return 1;
00092 
00093 free_ctx:
00094         g_free(ctx);
00095         return 0;
00096 }
00097 
00098 static int hw_dev_open(int dev_index)
00099 {
00100         struct sr_dev_inst *sdi;
00101         struct context *ctx;
00102         int ret;
00103 
00104         if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
00105                 return SR_ERR;
00106         ctx = sdi->priv;
00107 
00108         ret = snd_pcm_open(&ctx->capture_handle, AUDIO_DEV,
00109                            SND_PCM_STREAM_CAPTURE, 0);
00110         if (ret < 0) {
00111                 sr_err("alsa: can't open audio device %s (%s)", AUDIO_DEV,
00112                        snd_strerror(ret));
00113                 return SR_ERR;
00114         }
00115 
00116         ret = snd_pcm_hw_params_malloc(&ctx->hw_params);
00117         if (ret < 0) {
00118                 sr_err("alsa: can't allocate hardware parameter structure (%s)",
00119                        snd_strerror(ret));
00120                 return SR_ERR;
00121         }
00122 
00123         ret = snd_pcm_hw_params_any(ctx->capture_handle, ctx->hw_params);
00124         if (ret < 0) {
00125                 sr_err("alsa: can't initialize hardware parameter structure "
00126                        "(%s)", snd_strerror(ret));
00127                 return SR_ERR;
00128         }
00129 
00130         return SR_OK;
00131 }
00132 
00133 static int hw_dev_close(int dev_index)
00134 {
00135         struct sr_dev_inst *sdi;
00136         struct context *ctx;
00137 
00138         if (!(sdi = sr_dev_inst_get(dev_insts, dev_index))) {
00139                 sr_err("alsa: %s: sdi was NULL", __func__);
00140                 return SR_ERR_BUG;
00141         }
00142 
00143         if (!(ctx = sdi->priv)) {
00144                 sr_err("alsa: %s: sdi->priv was NULL", __func__);
00145                 return SR_ERR_BUG;
00146         }
00147 
00148         // TODO: Return values of snd_*?
00149         if (ctx->hw_params)
00150                 snd_pcm_hw_params_free(ctx->hw_params);
00151         if (ctx->capture_handle)
00152                 snd_pcm_close(ctx->capture_handle);
00153 
00154         return SR_OK;
00155 }
00156 
00157 static int hw_cleanup(void)
00158 {
00159         struct sr_dev_inst *sdi;
00160 
00161         if (!(sdi = sr_dev_inst_get(dev_insts, 0))) {
00162                 sr_err("alsa: %s: sdi was NULL", __func__);
00163                 return SR_ERR_BUG;
00164         }
00165 
00166         sr_dev_inst_free(sdi);
00167 
00168         return SR_OK;
00169 }
00170 
00171 static void *hw_dev_info_get(int dev_index, int dev_info_id)
00172 {
00173         struct sr_dev_inst *sdi;
00174         struct context *ctx;
00175         void *info = NULL;
00176 
00177         if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
00178                 return NULL;
00179         ctx = sdi->priv;
00180 
00181         switch (dev_info_id) {
00182         case SR_DI_INST:
00183                 info = sdi;
00184                 break;
00185         case SR_DI_NUM_PROBES:
00186                 info = GINT_TO_POINTER(NUM_PROBES);
00187                 break;
00188         case SR_DI_PROBE_NAMES:
00189                 info = probe_names;
00190                 break;
00191         case SR_DI_CUR_SAMPLERATE:
00192                 info = &ctx->cur_rate;
00193                 break;
00194         // case SR_DI_PROBE_TYPE:
00195         //      info = GINT_TO_POINTER(SR_PROBE_TYPE_ANALOG);
00196         //      break;
00197         }
00198 
00199         return info;
00200 }
00201 
00202 static int hw_dev_status_get(int dev_index)
00203 {
00204         /* Avoid compiler warnings. */
00205         dev_index = dev_index;
00206 
00207         return SR_ST_ACTIVE;
00208 }
00209 
00210 static int *hw_hwcap_get_all(void)
00211 {
00212         return hwcaps;
00213 }
00214 
00215 static int hw_dev_config_set(int dev_index, int hwcap, void *value)
00216 {
00217         struct sr_dev_inst *sdi;
00218         struct context *ctx;
00219 
00220         if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
00221                 return SR_ERR;
00222         ctx = sdi->priv;
00223 
00224         switch (hwcap) {
00225         case SR_HWCAP_PROBECONFIG:
00226                 return SR_OK;
00227         case SR_HWCAP_SAMPLERATE:
00228                 ctx->cur_rate = *(uint64_t *)value;
00229                 return SR_OK;
00230         case SR_HWCAP_LIMIT_SAMPLES:
00231                 ctx->limit_samples = *(uint64_t *)value;
00232                 return SR_OK;
00233         default:
00234                 return SR_ERR;
00235         }
00236 }
00237 
00238 static int receive_data(int fd, int revents, void *cb_data)
00239 {
00240         struct sr_dev_inst *sdi = cb_data;
00241         struct context *ctx = sdi->priv;
00242         struct sr_datafeed_packet packet;
00243         struct sr_analog_sample *sample;
00244         unsigned int sample_size = sizeof(struct sr_analog_sample) +
00245                 (NUM_PROBES * sizeof(struct sr_analog_probe));
00246         char *outb;
00247         char inb[4096];
00248         int i, x, count;
00249 
00250         fd = fd;
00251         revents = revents;
00252 
00253         do {
00254                 memset(inb, 0, sizeof(inb));
00255                 count = snd_pcm_readi(ctx->capture_handle, inb,
00256                         MIN(4096 / 4, ctx->limit_samples));
00257                 if (count < 1) {
00258                         sr_err("alsa: Failed to read samples");
00259                         return FALSE;
00260                 }
00261 
00262                 if (!(outb = g_try_malloc(sample_size * count))) {
00263                         sr_err("alsa: %s: outb malloc failed", __func__);
00264                         return FALSE;
00265                 }
00266 
00267                 for (i = 0; i < count; i++) {
00268                         sample = (struct sr_analog_sample *)
00269                                                 (outb + (i * sample_size));
00270                         sample->num_probes = NUM_PROBES;
00271 
00272                         for (x = 0; x < NUM_PROBES; x++) {
00273                                 sample->probes[x].val =
00274                                         *(uint16_t *)(inb + (i * 4) + (x * 2));
00275                                 sample->probes[x].val &= ((1 << 16) - 1);
00276                                 sample->probes[x].res = 16;
00277                         }
00278                 }
00279 
00280                 packet.type = SR_DF_ANALOG;
00281                 packet.length = count * sample_size;
00282                 packet.unitsize = sample_size;
00283                 packet.payload = outb;
00284                 sr_session_send(sdi, &packet);
00285                 g_free(outb);
00286                 ctx->limit_samples -= count;
00287 
00288         } while (ctx->limit_samples > 0);
00289 
00290         packet.type = SR_DF_END;
00291         sr_session_send(sdi, &packet);
00292 
00293         return TRUE;
00294 }
00295 
00296 static int hw_dev_acquisition_start(int dev_index, void *cb_data)
00297 {
00298         struct sr_dev_inst *sdi;
00299         struct context *ctx;
00300         struct sr_datafeed_packet packet;
00301         struct sr_datafeed_header header;
00302         struct pollfd *ufds;
00303         int count;
00304         int ret;
00305 
00306         if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
00307                 return SR_ERR;
00308         ctx = sdi->priv;
00309 
00310         ret = snd_pcm_hw_params_set_access(ctx->capture_handle,
00311                         ctx->hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
00312         if (ret < 0) {
00313                 sr_err("alsa: can't set access type (%s)", snd_strerror(ret));
00314                 return SR_ERR;
00315         }
00316 
00317         /* FIXME: Hardcoded for 16bits */
00318         ret = snd_pcm_hw_params_set_format(ctx->capture_handle,
00319                         ctx->hw_params, SND_PCM_FORMAT_S16_LE);
00320         if (ret < 0) {
00321                 sr_err("alsa: can't set sample format (%s)", snd_strerror(ret));
00322                 return SR_ERR;
00323         }
00324 
00325         ret = snd_pcm_hw_params_set_rate_near(ctx->capture_handle,
00326                         ctx->hw_params, (unsigned int *)&ctx->cur_rate, 0);
00327         if (ret < 0) {
00328                 sr_err("alsa: can't set sample rate (%s)", snd_strerror(ret));
00329                 return SR_ERR;
00330         }
00331 
00332         ret = snd_pcm_hw_params_set_channels(ctx->capture_handle,
00333                         ctx->hw_params, NUM_PROBES);
00334         if (ret < 0) {
00335                 sr_err("alsa: can't set channel count (%s)", snd_strerror(ret));
00336                 return SR_ERR;
00337         }
00338 
00339         ret = snd_pcm_hw_params(ctx->capture_handle, ctx->hw_params);
00340         if (ret < 0) {
00341                 sr_err("alsa: can't set parameters (%s)", snd_strerror(ret));
00342                 return SR_ERR;
00343         }
00344 
00345         ret = snd_pcm_prepare(ctx->capture_handle);
00346         if (ret < 0) {
00347                 sr_err("alsa: can't prepare audio interface for use (%s)",
00348                        snd_strerror(ret));
00349                 return SR_ERR;
00350         }
00351 
00352         count = snd_pcm_poll_descriptors_count(ctx->capture_handle);
00353         if (count < 1) {
00354                 sr_err("alsa: Unable to obtain poll descriptors count");
00355                 return SR_ERR;
00356         }
00357 
00358         if (!(ufds = g_try_malloc(count * sizeof(struct pollfd)))) {
00359                 sr_err("alsa: %s: ufds malloc failed", __func__);
00360                 return SR_ERR_MALLOC;
00361         }
00362 
00363         ret = snd_pcm_poll_descriptors(ctx->capture_handle, ufds, count);
00364         if (ret < 0) {
00365                 sr_err("alsa: Unable to obtain poll descriptors (%s)",
00366                        snd_strerror(ret));
00367                 g_free(ufds);
00368                 return SR_ERR;
00369         }
00370 
00371         ctx->session_dev_id = cb_data;
00372         sr_source_add(ufds[0].fd, ufds[0].events, 10, receive_data, sdi);
00373 
00374         packet.type = SR_DF_HEADER;
00375         packet.length = sizeof(struct sr_datafeed_header);
00376         packet.payload = (unsigned char *)&header;
00377         header.feed_version = 1;
00378         gettimeofday(&header.starttime, NULL);
00379         header.samplerate = ctx->cur_rate;
00380         header.num_analog_probes = NUM_PROBES;
00381         header.num_logic_probes = 0;
00382         header.protocol_id = SR_PROTO_RAW;
00383         sr_session_send(cb_data, &packet);
00384         g_free(ufds);
00385 
00386         return SR_OK;
00387 }
00388 
00389 /* TODO: This stops acquisition on ALL devices, ignoring dev_index. */
00390 static int hw_dev_acquisition_stop(int dev_index, void *cb_data)
00391 {
00392         /* Avoid compiler warnings. */
00393         (void)dev_index;
00394         (void)cb_data;
00395 
00396         return SR_OK;
00397 }
00398 
00399 SR_PRIV struct sr_dev_driver alsa_driver_info = {
00400         .name = "alsa",
00401         .longname = "ALSA driver",
00402         .api_version = 1,
00403         .init = hw_init,
00404         .cleanup = hw_cleanup,
00405         .dev_open = hw_dev_open,
00406         .dev_close = hw_dev_close,
00407         .dev_info_get = hw_dev_info_get,
00408         .dev_status_get = hw_dev_status_get,
00409         .hwcap_get_all = hw_hwcap_get_all,
00410         .dev_config_set = hw_dev_config_set,
00411         .dev_acquisition_start = hw_dev_acquisition_start,
00412         .dev_acquisition_stop = hw_dev_acquisition_stop,
00413 };
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