src/output/vcd.c

   1 /*
   2  * This file is part of the libsigrok project.
   3  *
   4  * Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
   5  * Copyright (C) 2013 Bert Vermeulen <bert@biot.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <config.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <glib.h>
  25 #include <libsigrok/libsigrok.h>
  26 #include "libsigrok-internal.h"
  27
  28 #define LOG_PREFIX "output/vcd"
  29
  30 struct context {
  31         int num_enabled_channels;
  32         uint8_t *prevsample;
  33         gboolean header_done;
  34         int period;
  35         int *channel_index;
  36         uint64_t samplerate;
  37         uint64_t samplecount;
  38 };
  39
  40 static int init(struct sr_output *o, GHashTable *options)
  41 {
  42         struct context *ctx;
  43         struct sr_channel *ch;
  44         GSList *l;
  45         int num_enabled_channels, i;
  46
  47         (void)options;
  48
  49         num_enabled_channels = 0;
  50         for (l = o->sdi->channels; l; l = l->next) {
  51                 ch = l->data;
  52                 if (ch->type != SR_CHANNEL_LOGIC)
  53                         continue;
  54                 if (!ch->enabled)
  55                         continue;
  56                 num_enabled_channels++;
  57         }
  58         if (num_enabled_channels > 94) {
  59                 sr_err("VCD only supports 94 channels.");
  60                 return SR_ERR;
  61         }
  62
  63         ctx = g_malloc0(sizeof(struct context));
  64         o->priv = ctx;
  65         ctx->num_enabled_channels = num_enabled_channels;
  66         ctx->channel_index = g_malloc(sizeof(int) * ctx->num_enabled_channels);
  67
  68         /* Once more to map the enabled channels. */
  69         for (i = 0, l = o->sdi->channels; l; l = l->next) {
  70                 ch = l->data;
  71                 if (ch->type != SR_CHANNEL_LOGIC)
  72                         continue;
  73                 if (!ch->enabled)
  74                         continue;
  75                 ctx->channel_index[i++] = ch->index;
  76         }
  77
  78         return SR_OK;
  79 }
  80
  81 static GString *gen_header(const struct sr_output *o)
  82 {
  83         struct context *ctx;
  84         struct sr_channel *ch;
  85         GVariant *gvar;
  86         GString *header;
  87         GSList *l;
  88         time_t t;
  89         int num_channels, i;
  90         char *samplerate_s, *frequency_s, *timestamp;
  91
  92         ctx = o->priv;
  93         header = g_string_sized_new(512);
  94         num_channels = g_slist_length(o->sdi->channels);
  95
  96         /* timestamp */
  97         t = time(NULL);
  98         timestamp = g_strdup(ctime(&t));
  99         timestamp[strlen(timestamp) - 1] = 0;
 100         g_string_printf(header, "$date %s $end\n", timestamp);
 101         g_free(timestamp);
 102
 103         /* generator */
 104         g_string_append_printf(header, "$version %s %s $end\n",
 105                         PACKAGE_NAME, sr_package_version_string_get());
 106         g_string_append_printf(header, "$comment\n  Acquisition with "
 107                         "%d/%d channels", ctx->num_enabled_channels, num_channels);
 108
 109         if (ctx->samplerate == 0) {
 110                 if (sr_config_get(o->sdi->driver, o->sdi, NULL, SR_CONF_SAMPLERATE,
 111                                 &gvar) == SR_OK) {
 112                         ctx->samplerate = g_variant_get_uint64(gvar);
 113                         g_variant_unref(gvar);
 114                 }
 115         }
 116         if (ctx->samplerate != 0) {
 117                 samplerate_s = sr_samplerate_string(ctx->samplerate);
 118                 g_string_append_printf(header, " at %s", samplerate_s);
 119                 g_free(samplerate_s);
 120         }
 121         g_string_append_printf(header, "\n$end\n");
 122
 123         /* timescale */
 124         /* VCD can only handle 1/10/100 (s - fs), so scale up first */
 125         if (ctx->samplerate > SR_MHZ(1))
 126                 ctx->period = SR_GHZ(1);
 127         else if (ctx->samplerate > SR_KHZ(1))
 128                 ctx->period = SR_MHZ(1);
 129         else
 130                 ctx->period = SR_KHZ(1);
 131         frequency_s = sr_period_string(1, ctx->period);
 132         g_string_append_printf(header, "$timescale %s $end\n", frequency_s);
 133         g_free(frequency_s);
 134
 135         /* scope */
 136         g_string_append_printf(header, "$scope module %s $end\n", PACKAGE_NAME);
 137
 138         /* Wires / channels */
 139         for (i = 0, l = o->sdi->channels; l; l = l->next) {
 140                 ch = l->data;
 141                 if (ch->type != SR_CHANNEL_LOGIC)
 142                         continue;
 143                 if (!ch->enabled)
 144                         continue;
 145                 g_string_append_printf(header, "$var wire 1 %c %s $end\n",
 146                                 (char)('!' + i), ch->name);
 147                 i++;
 148         }
 149
 150         g_string_append(header, "$upscope $end\n$enddefinitions $end\n");
 151
 152         return header;
 153 }
 154
 155 static int receive(const struct sr_output *o, const struct sr_datafeed_packet *packet,
 156                 GString **out)
 157 {
 158         const struct sr_datafeed_meta *meta;
 159         const struct sr_datafeed_logic *logic;
 160         const struct sr_config *src;
 161         GSList *l;
 162         struct context *ctx;
 163         unsigned int i;
 164         int p, curbit, prevbit, index;
 165         uint8_t *sample;
 166         gboolean timestamp_written;
 167
 168         *out = NULL;
 169         if (!o || !o->priv)
 170                 return SR_ERR_BUG;
 171         ctx = o->priv;
 172
 173         switch (packet->type) {
 174         case SR_DF_META:
 175                 meta = packet->payload;
 176                 for (l = meta->config; l; l = l->next) {
 177                         src = l->data;
 178                         if (src->key != SR_CONF_SAMPLERATE)
 179                                 continue;
 180                         ctx->samplerate = g_variant_get_uint64(src->data);
 181                 }
 182                 break;
 183         case SR_DF_LOGIC:
 184                 logic = packet->payload;
 185
 186                 if (!ctx->header_done) {
 187                         *out = gen_header(o);
 188                         ctx->header_done = TRUE;
 189                 } else {
 190                         *out = g_string_sized_new(512);
 191                 }
 192
 193                 if (!ctx->prevsample) {
 194                         /* Can't allocate this until we know the stream's unitsize. */
 195                         ctx->prevsample = g_malloc0(logic->unitsize);
 196                 }
 197
 198                 for (i = 0; i <= logic->length - logic->unitsize; i += logic->unitsize) {
 199                         sample = logic->data + i;
 200                         timestamp_written = FALSE;
 201
 202                         for (p = 0; p < ctx->num_enabled_channels; p++) {
 203                                 /*
 204                                  * TODO Check whether the mapping from
 205                                  * data image positions to channel numbers
 206                                  * is required. Experiments suggest that
 207                                  * the data image "is dense", and packs
 208                                  * bits of enabled channels, and leaves no
 209                                  * room for positions of disabled channels.
 210                                  */
 211                                 /* index = ctx->channel_index[p]; */
 212                                 index = p;
 213
 214                                 curbit = ((unsigned)sample[index / 8]
 215                                                 >> (index % 8)) & 1;
 216                                 prevbit = ((unsigned)ctx->prevsample[index / 8]
 217                                                 >> (index % 8)) & 1;
 218
 219                                 /* VCD only contains deltas/changes of signals. */
 220                                 if (prevbit == curbit && ctx->samplecount > 0)
 221                                         continue;
 222
 223                                 /* Output timestamp of subsequent signal changes. */
 224                                 if (!timestamp_written)
 225                                         g_string_append_printf(*out, "#%.0f",
 226                                                 (double)ctx->samplecount /
 227                                                         ctx->samplerate * ctx->period);
 228
 229                                 /* Output which signal changed to which value. */
 230                                 g_string_append_c(*out, ' ');
 231                                 g_string_append_c(*out, '0' + curbit);
 232                                 g_string_append_c(*out, '!' + p);
 233
 234                                 timestamp_written = TRUE;
 235                         }
 236
 237                         if (timestamp_written)
 238                                 g_string_append_c(*out, '\n');
 239
 240                         ctx->samplecount++;
 241                         memcpy(ctx->prevsample, sample, logic->unitsize);
 242                 }
 243                 break;
 244         case SR_DF_END:
 245                 /* Write final timestamp as length indicator. */
 246                 *out = g_string_sized_new(512);
 247                 g_string_printf(*out, "#%.0f\n",
 248                                 (double)ctx->samplecount / ctx->samplerate * ctx->period);
 249                 break;
 250         }
 251
 252         return SR_OK;
 253 }
 254
 255 static int cleanup(struct sr_output *o)
 256 {
 257         struct context *ctx;
 258
 259         if (!o || !o->priv)
 260                 return SR_ERR_ARG;
 261
 262         ctx = o->priv;
 263         g_free(ctx->prevsample);
 264         g_free(ctx->channel_index);
 265         g_free(ctx);
 266
 267         return SR_OK;
 268 }
 269
 270 struct sr_output_module output_vcd = {
 271         .id = "vcd",
 272         .name = "VCD",
 273         .desc = "Value Change Dump data",
 274         .exts = (const char*[]){"vcd", NULL},
 275         .flags = 0,
 276         .options = NULL,
 277         .init = init,
 278         .receive = receive,
 279         .cleanup = cleanup,
 280 };