src/hardware/pipistrello-ols/protocol.c

   1 /*
   2  * This file is part of the libsigrok project.
   3  *
   4  * Copyright (C) 2013 Bert Vermeulen <bert@biot.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 3 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, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include "protocol.h"
  22
  23 SR_PRIV int write_shortcommand(struct dev_context *devc, uint8_t command)
  24 {
  25         uint8_t buf[1];
  26         int bytes_written;
  27
  28         sr_dbg("Sending cmd 0x%.2x.", command);
  29         buf[0] = command;
  30         bytes_written = ftdi_write_data(devc->ftdic, buf, 1);
  31         if (bytes_written < 0) {
  32                 sr_err("Failed to write FTDI data (%d): %s.",
  33                        bytes_written, ftdi_get_error_string(devc->ftdic));
  34                 return SR_ERR;
  35         } else if (bytes_written != 1) {
  36                 sr_err("FTDI write error, only %d/%d bytes written: %s.",
  37                        bytes_written, 1, ftdi_get_error_string(devc->ftdic));
  38                 return SR_ERR;
  39         }
  40
  41         return SR_OK;
  42 }
  43
  44 SR_PRIV int write_longcommand(struct dev_context *devc, uint8_t command, uint8_t *data)
  45 {
  46         uint8_t buf[5];
  47         int bytes_written;
  48
  49         sr_dbg("Sending cmd 0x%.2x data 0x%.2x%.2x%.2x%.2x.", command,
  50                         data[0], data[1], data[2], data[3]);
  51         buf[0] = command;
  52         buf[1] = data[0];
  53         buf[2] = data[1];
  54         buf[3] = data[2];
  55         buf[4] = data[3];
  56         bytes_written = ftdi_write_data(devc->ftdic, buf, 5);
  57         if (bytes_written < 0) {
  58                 sr_err("Failed to write FTDI data (%d): %s.",
  59                        bytes_written, ftdi_get_error_string(devc->ftdic));
  60                 return SR_ERR;
  61         } else if (bytes_written != 5) {
  62                 sr_err("FTDI write error, only %d/%d bytes written: %s.",
  63                        bytes_written, 1, ftdi_get_error_string(devc->ftdic));
  64                 return SR_ERR;
  65         }
  66
  67         return SR_OK;
  68 }
  69
  70 SR_PRIV int p_ols_open(struct dev_context *devc)
  71 {
  72         int ret;
  73
  74         /* Note: Caller checks devc and devc->ftdic. */
  75
  76         ret = ftdi_set_interface(devc->ftdic, INTERFACE_B);
  77         if (ret < 0) {
  78                 sr_err("Failed to set FTDI interface B (%d): %s", ret,
  79                        ftdi_get_error_string(devc->ftdic));
  80                 return SR_ERR;
  81         }
  82
  83         ret = ftdi_usb_open_desc(devc->ftdic, USB_VENDOR_ID, USB_DEVICE_ID,
  84                                  USB_IPRODUCT, NULL);
  85         if (ret < 0) {
  86                 /* Log errors, except for -3 ("device not found"). */
  87                 if (ret != -3)
  88                         sr_err("Failed to open device (%d): %s", ret,
  89                                ftdi_get_error_string(devc->ftdic));
  90                 return SR_ERR;
  91         }
  92
  93         if ((ret = PURGE_FTDI_BOTH(devc->ftdic)) < 0) {
  94                 sr_err("Failed to purge FTDI RX/TX buffers (%d): %s.",
  95                        ret, ftdi_get_error_string(devc->ftdic));
  96                 goto err_open_close_ftdic;
  97         }
  98
  99         ret = ftdi_set_bitmode(devc->ftdic, 0xff, BITMODE_RESET);
 100         if (ret < 0) {
 101                 sr_err("Failed to reset the FTDI chip bitmode (%d): %s.",
 102                        ret, ftdi_get_error_string(devc->ftdic));
 103                 goto err_open_close_ftdic;
 104         }
 105
 106         ret = ftdi_set_latency_timer(devc->ftdic, 16);
 107         if (ret < 0) {
 108                 sr_err("Failed to set FTDI latency timer (%d): %s.",
 109                        ret, ftdi_get_error_string(devc->ftdic));
 110                 goto err_open_close_ftdic;
 111         }
 112
 113         ret = ftdi_read_data_set_chunksize(devc->ftdic, 64 * 1024);
 114         if (ret < 0) {
 115                 sr_err("Failed to set FTDI read data chunk size (%d): %s.",
 116                        ret, ftdi_get_error_string(devc->ftdic));
 117                 goto err_open_close_ftdic;
 118         }
 119
 120         return SR_OK;
 121
 122 err_open_close_ftdic:
 123         ftdi_usb_close(devc->ftdic);
 124
 125         return SR_ERR;
 126 }
 127
 128 SR_PRIV int p_ols_close(struct dev_context *devc)
 129 {
 130         int ret;
 131
 132         /* Note: Caller checks devc and devc->ftdic. */
 133
 134         if ((ret = ftdi_usb_close(devc->ftdic)) < 0) {
 135                 sr_err("Failed to close FTDI device (%d): %s.",
 136                        ret, ftdi_get_error_string(devc->ftdic));
 137                 return SR_ERR;
 138         }
 139
 140         return SR_OK;
 141 }
 142
 143 /* Configures the channel mask based on which channels are enabled. */
 144 SR_PRIV void pols_channel_mask(const struct sr_dev_inst *sdi)
 145 {
 146         struct dev_context *devc;
 147         struct sr_channel *channel;
 148         const GSList *l;
 149
 150         devc = sdi->priv;
 151
 152         devc->channel_mask = 0;
 153         for (l = sdi->channels; l; l = l->next) {
 154                 channel = l->data;
 155                 if (channel->enabled)
 156                         devc->channel_mask |= 1 << channel->index;
 157         }
 158 }
 159
 160 SR_PRIV int pols_convert_trigger(const struct sr_dev_inst *sdi)
 161 {
 162         struct dev_context *devc;
 163         struct sr_trigger *trigger;
 164         struct sr_trigger_stage *stage;
 165         struct sr_trigger_match *match;
 166         const GSList *l, *m;
 167         int i;
 168
 169         devc = sdi->priv;
 170
 171         devc->num_stages = 0;
 172         for (i = 0; i < NUM_TRIGGER_STAGES; i++) {
 173                 devc->trigger_mask[i] = 0;
 174                 devc->trigger_value[i] = 0;
 175                 devc->trigger_edge[i] = 0;
 176         }
 177
 178         if (!(trigger = sr_session_trigger_get(sdi->session)))
 179                 return SR_OK;
 180
 181         devc->num_stages = g_slist_length(trigger->stages);
 182         if (devc->num_stages > NUM_TRIGGER_STAGES) {
 183                 sr_err("This device only supports %d trigger stages.",
 184                                 NUM_TRIGGER_STAGES);
 185                 return SR_ERR;
 186         }
 187
 188         for (l = trigger->stages; l; l = l->next) {
 189                 stage = l->data;
 190                 for (m = stage->matches; m; m = m->next) {
 191                         match = m->data;
 192                         if (!match->channel->enabled)
 193                                 /* Ignore disabled channels with a trigger. */
 194                                 continue;
 195                         devc->trigger_mask[stage->stage] |= 1 << match->channel->index;
 196                         if (match->match == SR_TRIGGER_ONE || match->match == SR_TRIGGER_RISING)
 197                                 devc->trigger_value[stage->stage] |= 1 << match->channel->index;
 198                         if (match->match == SR_TRIGGER_RISING || match->match == SR_TRIGGER_FALLING)
 199                                 devc->trigger_edge[stage->stage] |= 1 << match->channel->index;
 200                 }
 201         }
 202
 203         return SR_OK;
 204 }
 205
 206 SR_PRIV struct sr_dev_inst *p_ols_get_metadata(uint8_t *buf, int bytes_read, struct dev_context *devc)
 207 {
 208         struct sr_dev_inst *sdi;
 209         uint32_t tmp_int, ui;
 210         uint8_t key, type, token;
 211         GString *tmp_str, *devname, *version;
 212         guchar tmp_c;
 213         int index;
 214
 215         sdi = g_malloc0(sizeof(struct sr_dev_inst));
 216         sdi->status = SR_ST_INACTIVE;
 217         sdi->priv = devc;
 218
 219         devname = g_string_new("");
 220         version = g_string_new("");
 221
 222         index = 0;
 223         while (index < bytes_read) {
 224                 key = buf[index++];
 225                 if (key == 0x00) {
 226                         sr_dbg("Got metadata key 0x00, metadata ends.");
 227                         break;
 228                 }
 229                 type = key >> 5;
 230                 token = key & 0x1f;
 231                 switch (type) {
 232                 case 0:
 233                         /* NULL-terminated string */
 234                         tmp_str = g_string_new("");
 235                         while ((index < bytes_read) && ((tmp_c = buf[index++]) != '\0'))
 236                                 g_string_append_c(tmp_str, tmp_c);
 237                         sr_dbg("Got metadata key 0x%.2x value '%s'.",
 238                                key, tmp_str->str);
 239                         switch (token) {
 240                         case 0x01:
 241                                 /* Device name */
 242                                 devname = g_string_append(devname, tmp_str->str);
 243                                 break;
 244                         case 0x02:
 245                                 /* FPGA firmware version */
 246                                 if (version->len)
 247                                         g_string_append(version, ", ");
 248                                 g_string_append(version, "FPGA version ");
 249                                 g_string_append(version, tmp_str->str);
 250                                 break;
 251                         case 0x03:
 252                                 /* Ancillary version */
 253                                 if (version->len)
 254                                         g_string_append(version, ", ");
 255                                 g_string_append(version, "Ancillary version ");
 256                                 g_string_append(version, tmp_str->str);
 257                                 break;
 258                         default:
 259                                 sr_info("Unknown token 0x%.2x: '%s'",
 260                                         token, tmp_str->str);
 261                                 break;
 262                         }
 263                         g_string_free(tmp_str, TRUE);
 264                         break;
 265                 case 1:
 266                         /* 32-bit unsigned integer */
 267                         tmp_int = RB32(&buf[index]);
 268                         index += sizeof(uint32_t);
 269                         sr_dbg("Got metadata key 0x%.2x value 0x%.8x.",
 270                                key, tmp_int);
 271                         switch (token) {
 272                         case 0x00:
 273                                 /* Number of usable channels */
 274                                 for (ui = 0; ui < tmp_int; ui++)
 275                                         sr_channel_new(sdi, ui, SR_CHANNEL_LOGIC, TRUE,
 276                                                         p_ols_channel_names[ui]);
 277                                 break;
 278                         case 0x01:
 279                                 /* Amount of sample memory available (bytes) */
 280                                 devc->max_samplebytes = tmp_int;
 281                                 break;
 282                         case 0x02:
 283                                 /* Amount of dynamic memory available (bytes) */
 284                                 /* what is this for? */
 285                                 break;
 286                         case 0x03:
 287                                 /* Maximum sample rate (Hz) */
 288                                 devc->max_samplerate = tmp_int;
 289                                 break;
 290                         case 0x04:
 291                                 /* protocol version */
 292                                 devc->protocol_version = tmp_int;
 293                                 break;
 294                         default:
 295                                 sr_info("Unknown token 0x%.2x: 0x%.8x.",
 296                                         token, tmp_int);
 297                                 break;
 298                         }
 299                         break;
 300                 case 2:
 301                         /* 8-bit unsigned integer */
 302                         tmp_c = buf[index++];
 303                         sr_dbg("Got metadata key 0x%.2x value 0x%.2x.",
 304                                key, tmp_c);
 305                         switch (token) {
 306                         case 0x00:
 307                                 /* Number of usable channels */
 308                                 for (ui = 0; ui < tmp_c; ui++)
 309                                         sr_channel_new(sdi, ui, SR_CHANNEL_LOGIC, TRUE,
 310                                                         p_ols_channel_names[ui]);
 311                                 break;
 312                         case 0x01:
 313                                 /* protocol version */
 314                                 devc->protocol_version = tmp_c;
 315                                 break;
 316                         default:
 317                                 sr_info("Unknown token 0x%.2x: 0x%.2x.",
 318                                         token, tmp_c);
 319                                 break;
 320                         }
 321                         break;
 322                 default:
 323                         /* unknown type */
 324                         break;
 325                 }
 326         }
 327
 328         sdi->model = devname->str;
 329         sdi->version = version->str;
 330         g_string_free(devname, FALSE);
 331         g_string_free(version, FALSE);
 332
 333         return sdi;
 334 }
 335
 336 SR_PRIV int p_ols_set_samplerate(const struct sr_dev_inst *sdi,
 337                 const uint64_t samplerate)
 338 {
 339         struct dev_context *devc;
 340
 341         devc = sdi->priv;
 342         if (devc->max_samplerate && samplerate > devc->max_samplerate)
 343                 return SR_ERR_SAMPLERATE;
 344
 345         if (samplerate > CLOCK_RATE) {
 346                 sr_info("Enabling demux mode.");
 347                 devc->flag_reg |= FLAG_DEMUX;
 348                 devc->flag_reg &= ~FLAG_FILTER;
 349                 devc->max_channels = NUM_CHANNELS / 2;
 350                 devc->cur_samplerate_divider = (CLOCK_RATE * 2 / samplerate) - 1;
 351         } else {
 352                 sr_info("Disabling demux mode.");
 353                 devc->flag_reg &= ~FLAG_DEMUX;
 354                 devc->flag_reg |= FLAG_FILTER;
 355                 devc->max_channels = NUM_CHANNELS;
 356                 devc->cur_samplerate_divider = (CLOCK_RATE / samplerate) - 1;
 357         }
 358
 359         /* Calculate actual samplerate used and complain if it is different
 360          * from the requested.
 361          */
 362         devc->cur_samplerate = CLOCK_RATE / (devc->cur_samplerate_divider + 1);
 363         if (devc->flag_reg & FLAG_DEMUX)
 364                 devc->cur_samplerate *= 2;
 365         if (devc->cur_samplerate != samplerate)
 366                 sr_info("Can't match samplerate %" PRIu64 ", using %"
 367                        PRIu64 ".", samplerate, devc->cur_samplerate);
 368
 369         return SR_OK;
 370 }
 371
 372 SR_PRIV int p_ols_receive_data(int fd, int revents, void *cb_data)
 373 {
 374         struct dev_context *devc;
 375         struct sr_dev_inst *sdi;
 376         struct sr_datafeed_packet packet;
 377         struct sr_datafeed_logic logic;
 378         uint32_t sample;
 379         int num_channels, offset, j;
 380         int bytes_read, index;
 381         unsigned int i;
 382         unsigned char byte;
 383
 384         (void)fd;
 385         (void)revents;
 386
 387         sdi = cb_data;
 388         devc = sdi->priv;
 389
 390         if (devc->num_transfers++ == 0) {
 391                 devc->raw_sample_buf = g_try_malloc(devc->limit_samples * 4);
 392                 if (!devc->raw_sample_buf) {
 393                         sr_err("Sample buffer malloc failed.");
 394                         return FALSE;
 395                 }
 396                 /* fill with 1010... for debugging */
 397                 memset(devc->raw_sample_buf, 0x82, devc->limit_samples * 4);
 398         }
 399
 400         if ((devc->num_samples < devc->limit_samples) && (devc->cnt_samples < devc->max_samples)) {
 401
 402                 num_channels = 0;
 403                 for (i = NUM_CHANNELS; i > 0x02; i /= 2) {
 404                         if ((devc->flag_reg & i) == 0) {
 405                                 num_channels++;
 406                         }
 407                 }
 408
 409                 /* Get a block of data. */
 410                 bytes_read = ftdi_read_data(devc->ftdic, devc->ftdi_buf, FTDI_BUF_SIZE);
 411                 if (bytes_read < 0) {
 412                         sr_err("Failed to read FTDI data (%d): %s.",
 413                                bytes_read, ftdi_get_error_string(devc->ftdic));
 414                         sr_dev_acquisition_stop(sdi);
 415                         return FALSE;
 416                 }
 417                 if (bytes_read == 0) {
 418                         sr_spew("Received 0 bytes, nothing to do.");
 419                         return TRUE;
 420                 }
 421
 422                 sr_dbg("Received %d bytes", bytes_read);
 423
 424                 index = 0;
 425                 while (index < bytes_read) {
 426                         byte = devc->ftdi_buf[index++];
 427                         devc->cnt_bytes++;
 428
 429                         devc->sample[devc->num_bytes++] = byte;
 430                         sr_spew("Received byte 0x%.2x.", byte);
 431
 432                         if ((devc->flag_reg & FLAG_DEMUX) && (devc->flag_reg & FLAG_RLE)) {
 433                                 /* RLE in demux mode must be processed differently
 434                                 * since in this case the RLE encoder is operating on pairs of samples.
 435                                 */
 436                                 if (devc->num_bytes == num_channels * 2) {
 437                                         devc->cnt_samples += 2;
 438                                         devc->cnt_samples_rle += 2;
 439                                         /*
 440                                          * Got a sample pair. Convert from the OLS's little-endian
 441                                          * sample to the local format.
 442                                          */
 443                                         sample = devc->sample[0] | (devc->sample[1] << 8) \
 444                                                         | (devc->sample[2] << 16) | (devc->sample[3] << 24);
 445                                         sr_spew("Received sample pair 0x%.*x.", devc->num_bytes * 2, sample);
 446
 447                                         /*
 448                                          * In RLE mode the high bit of the sample pair is the
 449                                          * "count" flag, meaning this sample pair is the number
 450                                          * of times the previous sample pair occurred.
 451                                          */
 452                                         if (devc->sample[devc->num_bytes - 1] & 0x80) {
 453                                                 /* Clear the high bit. */
 454                                                 sample &= ~(0x80 << (devc->num_bytes - 1) * 8);
 455                                                 devc->rle_count = sample;
 456                                                 devc->cnt_samples_rle += devc->rle_count * 2;
 457                                                 sr_dbg("RLE count: %u.", devc->rle_count * 2);
 458                                                 devc->num_bytes = 0;
 459                                                 continue;
 460                                         }
 461                                         devc->num_samples += (devc->rle_count + 1) * 2;
 462                                         if (devc->num_samples > devc->limit_samples) {
 463                                                 /* Save us from overrunning the buffer. */
 464                                                 devc->rle_count -= (devc->num_samples - devc->limit_samples) / 2;
 465                                                 devc->num_samples = devc->limit_samples;
 466                                                 index = bytes_read;
 467                                         }
 468
 469                                         /*
 470                                          * Some channel groups may have been turned
 471                                          * off, to speed up transfer between the
 472                                          * hardware and the PC. Expand that here before
 473                                          * submitting it over the session bus --
 474                                          * whatever is listening on the bus will be
 475                                          * expecting a full 32-bit sample, based on
 476                                          * the number of channels.
 477                                          */
 478                                         j = 0;
 479                                         /* expand first sample */
 480                                         memset(devc->tmp_sample, 0, 4);
 481                                         for (i = 0; i < 2; i++) {
 482                                                 if (((devc->flag_reg >> 2) & (1 << i)) == 0) {
 483                                                         /*
 484                                                          * This channel group was
 485                                                          * enabled, copy from received
 486                                                          * sample.
 487                                                          */
 488                                                         devc->tmp_sample[i] = devc->sample[j++];
 489                                                 }
 490                                         }
 491                                         /* Clear out the most significant bit of the sample */
 492                                         devc->tmp_sample[devc->num_bytes - 1] &= 0x7f;
 493                                         sr_spew("Expanded sample 1: 0x%.2x%.2x%.2x%.2x.",
 494                                                 devc->tmp_sample[3], devc->tmp_sample[2],
 495                                                 devc->tmp_sample[1], devc->tmp_sample[0]);
 496
 497                                         /* expand second sample */
 498                                         memset(devc->tmp_sample2, 0, 4);
 499                                         for (i = 0; i < 2; i++) {
 500                                                 if (((devc->flag_reg >> 2) & (1 << i)) == 0) {
 501                                                         /*
 502                                                          * This channel group was
 503                                                          * enabled, copy from received
 504                                                          * sample.
 505                                                          */
 506                                                         devc->tmp_sample2[i] = devc->sample[j++];
 507                                                 }
 508                                         }
 509                                         /* Clear out the most significant bit of the sample */
 510                                         devc->tmp_sample2[devc->num_bytes - 1] &= 0x7f;
 511                                         sr_spew("Expanded sample 2: 0x%.2x%.2x%.2x%.2x.",
 512                                                 devc->tmp_sample2[3], devc->tmp_sample2[2],
 513                                                 devc->tmp_sample2[1], devc->tmp_sample2[0]);
 514
 515                                         /*
 516                                          * OLS sends its sample buffer backwards.
 517                                          * store it in reverse order here, so we can dump
 518                                          * this on the session bus later.
 519                                          */
 520                                         offset = (devc->limit_samples - devc->num_samples) * 4;
 521                                         for (i = 0; i <= devc->rle_count; i++) {
 522                                                 memcpy(devc->raw_sample_buf + offset + (i * 8),
 523                                                                          devc->tmp_sample2, 4);
 524                                                 memcpy(devc->raw_sample_buf + offset + (4 + (i * 8)),
 525                                                                          devc->tmp_sample, 4);
 526                                         }
 527                                         memset(devc->sample, 0, 4);
 528                                         devc->num_bytes = 0;
 529                                         devc->rle_count = 0;
 530                                 }
 531                         }
 532                         else {
 533                                 if (devc->num_bytes == num_channels) {
 534                                         devc->cnt_samples++;
 535                                         devc->cnt_samples_rle++;
 536                                         /*
 537                                          * Got a full sample. Convert from the OLS's little-endian
 538                                          * sample to the local format.
 539                                          */
 540                                         sample = devc->sample[0] | (devc->sample[1] << 8) \
 541                                                         | (devc->sample[2] << 16) | (devc->sample[3] << 24);
 542                                         sr_spew("Received sample 0x%.*x.", devc->num_bytes * 2, sample);
 543                                         if (devc->flag_reg & FLAG_RLE) {
 544                                                 /*
 545                                                  * In RLE mode the high bit of the sample is the
 546                                                  * "count" flag, meaning this sample is the number
 547                                                  * of times the previous sample occurred.
 548                                                  */
 549                                                 if (devc->sample[devc->num_bytes - 1] & 0x80) {
 550                                                         /* Clear the high bit. */
 551                                                         sample &= ~(0x80 << (devc->num_bytes - 1) * 8);
 552                                                         devc->rle_count = sample;
 553                                                         devc->cnt_samples_rle += devc->rle_count;
 554                                                         sr_dbg("RLE count: %u.", devc->rle_count);
 555                                                         devc->num_bytes = 0;
 556                                                         continue;
 557                                                 }
 558                                         }
 559                                         devc->num_samples += devc->rle_count + 1;
 560                                         if (devc->num_samples > devc->limit_samples) {
 561                                                 /* Save us from overrunning the buffer. */
 562                                                 devc->rle_count -= devc->num_samples - devc->limit_samples;
 563                                                 devc->num_samples = devc->limit_samples;
 564                                                 index = bytes_read;
 565                                         }
 566
 567                                         if (num_channels < 4) {
 568                                                 /*
 569                                                  * Some channel groups may have been turned
 570                                                  * off, to speed up transfer between the
 571                                                  * hardware and the PC. Expand that here before
 572                                                  * submitting it over the session bus --
 573                                                  * whatever is listening on the bus will be
 574                                                  * expecting a full 32-bit sample, based on
 575                                                  * the number of channels.
 576                                                  */
 577                                                 j = 0;
 578                                                 memset(devc->tmp_sample, 0, 4);
 579                                                 for (i = 0; i < 4; i++) {
 580                                                         if (((devc->flag_reg >> 2) & (1 << i)) == 0) {
 581                                                                 /*
 582                                                                  * This channel group was
 583                                                                  * enabled, copy from received
 584                                                                  * sample.
 585                                                                  */
 586                                                                 devc->tmp_sample[i] = devc->sample[j++];
 587                                                         }
 588                                                 }
 589                                                 memcpy(devc->sample, devc->tmp_sample, 4);
 590                                                 sr_spew("Expanded sample: 0x%.8x.", sample);
 591                                         }
 592
 593                                         /*
 594                                          * Pipistrello OLS sends its sample buffer backwards.
 595                                          * store it in reverse order here, so we can dump
 596                                          * this on the session bus later.
 597                                          */
 598                                         offset = (devc->limit_samples - devc->num_samples) * 4;
 599                                         for (i = 0; i <= devc->rle_count; i++) {
 600                                                 memcpy(devc->raw_sample_buf + offset + (i * 4),
 601                                                                          devc->sample, 4);
 602                                         }
 603                                         memset(devc->sample, 0, 4);
 604                                         devc->num_bytes = 0;
 605                                         devc->rle_count = 0;
 606                                 }
 607                         }
 608                 }
 609                 return TRUE;
 610         } else {
 611                 do {
 612                         bytes_read = ftdi_read_data(devc->ftdic, devc->ftdi_buf, FTDI_BUF_SIZE);
 613                 } while (bytes_read > 0);
 614
 615                 /*
 616                  * We've acquired all the samples we asked for -- we're done.
 617                  * Send the (properly-ordered) buffer to the frontend.
 618                  */
 619                 sr_dbg("Received %d bytes, %d samples, %d decompressed samples.",
 620                                 devc->cnt_bytes, devc->cnt_samples,
 621                                 devc->cnt_samples_rle);
 622                 if (devc->trigger_at != -1) {
 623                         /*
 624                          * A trigger was set up, so we need to tell the frontend
 625                          * about it.
 626                          */
 627                         if (devc->trigger_at > 0) {
 628                                 /* There are pre-trigger samples, send those first. */
 629                                 packet.type = SR_DF_LOGIC;
 630                                 packet.payload = &logic;
 631                                 logic.length = devc->trigger_at * 4;
 632                                 logic.unitsize = 4;
 633                                 logic.data = devc->raw_sample_buf +
 634                                         (devc->limit_samples - devc->num_samples) * 4;
 635                                 sr_session_send(sdi, &packet);
 636                         }
 637
 638                         /* Send the trigger. */
 639                         std_session_send_df_trigger(sdi);
 640
 641                         /* Send post-trigger samples. */
 642                         packet.type = SR_DF_LOGIC;
 643                         packet.payload = &logic;
 644                         logic.length = (devc->num_samples * 4) - (devc->trigger_at * 4);
 645                         logic.unitsize = 4;
 646                         logic.data = devc->raw_sample_buf + devc->trigger_at * 4 +
 647                                 (devc->limit_samples - devc->num_samples) * 4;
 648                         sr_session_send(sdi, &packet);
 649                 } else {
 650                         /* no trigger was used */
 651                         packet.type = SR_DF_LOGIC;
 652                         packet.payload = &logic;
 653                         logic.length = devc->num_samples * 4;
 654                         logic.unitsize = 4;
 655                         logic.data = devc->raw_sample_buf +
 656                                 (devc->limit_samples - devc->num_samples) * 4;
 657                         sr_session_send(sdi, &packet);
 658                 }
 659                 g_free(devc->raw_sample_buf);
 660
 661                 sr_dev_acquisition_stop(sdi);
 662         }
 663
 664         return TRUE;
 665 }