src/hardware/sysclk-lwla/protocol.c

   1 /*
   2  * This file is part of the libsigrok project.
   3  *
   4  * Copyright (C) 2014 Daniel Elstner <daniel.kitta@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 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 <string.h>
  22 #include "protocol.h"
  23
  24 /* Bit mask for the RLE repeat-count-follows flag. */
  25 #define RLE_FLAG_LEN_FOLLOWS ((uint64_t)1 << 35)
  26
  27 /* Start address of capture status memory area to read. */
  28 #define CAP_STAT_ADDR 5
  29
  30 /* Number of 64-bit words read from the capture status memory. */
  31 #define CAP_STAT_LEN 5
  32
  33 /* The bitstream filenames are indexed by the clock_config enumeration.
  34  */
  35 static const char bitstream_map[][32] = {
  36         "sysclk-lwla1034-off.rbf",
  37         "sysclk-lwla1034-int.rbf",
  38         "sysclk-lwla1034-extpos.rbf",
  39         "sysclk-lwla1034-extneg.rbf",
  40 };
  41
  42 /* Submit an already filled-in USB transfer.
  43  */
  44 static int submit_transfer(struct dev_context *devc,
  45                            struct libusb_transfer *xfer)
  46 {
  47         int ret;
  48
  49         ret = libusb_submit_transfer(xfer);
  50
  51         if (ret != 0) {
  52                 sr_err("Submit transfer failed: %s.", libusb_error_name(ret));
  53                 devc->transfer_error = TRUE;
  54                 return SR_ERR;
  55         }
  56
  57         return SR_OK;
  58 }
  59
  60 /* Set up the LWLA in preparation for an acquisition session.
  61  */
  62 static int capture_setup(const struct sr_dev_inst *sdi)
  63 {
  64         struct dev_context *devc;
  65         struct acquisition_state *acq;
  66         uint64_t divider_count;
  67         uint64_t trigger_mask;
  68         uint64_t memory_limit;
  69         uint16_t command[3 + (10 * 4)];
  70
  71         devc = sdi->priv;
  72         acq  = devc->acquisition;
  73
  74         command[0] = LWLA_WORD(CMD_CAP_SETUP);
  75         command[1] = LWLA_WORD(0); /* address */
  76         command[2] = LWLA_WORD(10); /* length */
  77
  78         command[3] = LWLA_WORD_0(devc->channel_mask);
  79         command[4] = LWLA_WORD_1(devc->channel_mask);
  80         command[5] = LWLA_WORD_2(devc->channel_mask);
  81         command[6] = LWLA_WORD_3(devc->channel_mask);
  82
  83         /* Set the clock divide counter maximum for samplerates of up to
  84          * 100 MHz. At the highest samplerate of 125 MHz the clock divider
  85          * is bypassed.
  86          */
  87         if (!acq->bypass_clockdiv && devc->samplerate > 0)
  88                 divider_count = SR_MHZ(100) / devc->samplerate - 1;
  89         else
  90                 divider_count = 0;
  91
  92         command[7]  = LWLA_WORD_0(divider_count);
  93         command[8]  = LWLA_WORD_1(divider_count);
  94         command[9]  = LWLA_WORD_2(divider_count);
  95         command[10] = LWLA_WORD_3(divider_count);
  96
  97         command[11] = LWLA_WORD_0(devc->trigger_values);
  98         command[12] = LWLA_WORD_1(devc->trigger_values);
  99         command[13] = LWLA_WORD_2(devc->trigger_values);
 100         command[14] = LWLA_WORD_3(devc->trigger_values);
 101
 102         command[15] = LWLA_WORD_0(devc->trigger_edge_mask);
 103         command[16] = LWLA_WORD_1(devc->trigger_edge_mask);
 104         command[17] = LWLA_WORD_2(devc->trigger_edge_mask);
 105         command[18] = LWLA_WORD_3(devc->trigger_edge_mask);
 106
 107         trigger_mask = devc->trigger_mask;
 108         /* Set bits to select external TRG input edge. */
 109         if (devc->cfg_trigger_source == TRIGGER_EXT_TRG)
 110                 switch (devc->cfg_trigger_slope) {
 111                 case EDGE_POSITIVE:
 112                         trigger_mask |= (uint64_t)1 << 35;
 113                         break;
 114                 case EDGE_NEGATIVE:
 115                         trigger_mask |= (uint64_t)1 << 34;
 116                         break;
 117                 }
 118
 119         command[19] = LWLA_WORD_0(trigger_mask);
 120         command[20] = LWLA_WORD_1(trigger_mask);
 121         command[21] = LWLA_WORD_2(trigger_mask);
 122         command[22] = LWLA_WORD_3(trigger_mask);
 123
 124         /* Set the capture memory full threshold. This is slightly less
 125          * than the actual maximum, most likely in order to compensate for
 126          * pipeline latency.
 127          */
 128         memory_limit = MEMORY_DEPTH - 16;
 129
 130         command[23] = LWLA_WORD_0(memory_limit);
 131         command[24] = LWLA_WORD_1(memory_limit);
 132         command[25] = LWLA_WORD_2(memory_limit);
 133         command[26] = LWLA_WORD_3(memory_limit);
 134
 135         /* Fill remaining words with zeroes. */
 136         memset(&command[27], 0, sizeof(command) - 27 * sizeof(command[0]));
 137
 138         return lwla_send_command(sdi->conn, command, ARRAY_SIZE(command));
 139 }
 140
 141 /* Issue a register write command as an asynchronous USB transfer.
 142  */
 143 static int issue_write_reg(const struct sr_dev_inst *sdi,
 144                            unsigned int reg, unsigned int value)
 145 {
 146         struct dev_context *devc;
 147         struct acquisition_state *acq;
 148
 149         devc = sdi->priv;
 150         acq  = devc->acquisition;
 151
 152         acq->xfer_buf_out[0] = LWLA_WORD(CMD_WRITE_REG);
 153         acq->xfer_buf_out[1] = LWLA_WORD(reg);
 154         acq->xfer_buf_out[2] = LWLA_WORD_0(value);
 155         acq->xfer_buf_out[3] = LWLA_WORD_1(value);
 156
 157         acq->xfer_out->length = 4 * sizeof(uint16_t);
 158
 159         return submit_transfer(devc, acq->xfer_out);
 160 }
 161
 162 /* Issue a register write command as an asynchronous USB transfer for the
 163  * next register/value pair of the currently active register write sequence.
 164  */
 165 static int issue_next_write_reg(const struct sr_dev_inst *sdi)
 166 {
 167         struct dev_context *devc;
 168         struct regval_pair *regval;
 169         int ret;
 170
 171         devc = sdi->priv;
 172
 173         if (devc->reg_write_pos >= devc->reg_write_len) {
 174                 sr_err("Already written all registers in sequence.");
 175                 return SR_ERR_BUG;
 176         }
 177         regval = &devc->reg_write_seq[devc->reg_write_pos];
 178
 179         ret = issue_write_reg(sdi, regval->reg, regval->val);
 180         if (ret != SR_OK)
 181                 return ret;
 182
 183         ++devc->reg_write_pos;
 184         return SR_OK;
 185 }
 186
 187 /* Issue a capture status request as an asynchronous USB transfer.
 188  */
 189 static void request_capture_status(const struct sr_dev_inst *sdi)
 190 {
 191         struct dev_context *devc;
 192         struct acquisition_state *acq;
 193
 194         devc = sdi->priv;
 195         acq  = devc->acquisition;
 196
 197         acq->xfer_buf_out[0] = LWLA_WORD(CMD_CAP_STATUS);
 198         acq->xfer_buf_out[1] = LWLA_WORD(CAP_STAT_ADDR);
 199         acq->xfer_buf_out[2] = LWLA_WORD(CAP_STAT_LEN);
 200
 201         acq->xfer_out->length = 3 * sizeof(uint16_t);
 202
 203         if (submit_transfer(devc, acq->xfer_out) == SR_OK)
 204                 devc->state = STATE_STATUS_REQUEST;
 205 }
 206
 207 /* Issue a request for the capture buffer fill level as
 208  * an asynchronous USB transfer.
 209  */
 210 static void request_capture_length(const struct sr_dev_inst *sdi)
 211 {
 212         struct dev_context *devc;
 213         struct acquisition_state *acq;
 214
 215         devc = sdi->priv;
 216         acq  = devc->acquisition;
 217
 218         acq->xfer_buf_out[0] = LWLA_WORD(CMD_READ_REG);
 219         acq->xfer_buf_out[1] = LWLA_WORD(REG_MEM_FILL);
 220
 221         acq->xfer_out->length = 2 * sizeof(uint16_t);
 222
 223         if (submit_transfer(devc, acq->xfer_out) == SR_OK)
 224                 devc->state = STATE_LENGTH_REQUEST;
 225 }
 226
 227 /* Initiate the capture memory read operation:  Reset the acquisition state
 228  * and start a sequence of register writes in order to set up the device for
 229  * reading from the capture buffer.
 230  */
 231 static void issue_read_start(const struct sr_dev_inst *sdi)
 232 {
 233         struct dev_context *devc;
 234         struct acquisition_state *acq;
 235         struct regval_pair *regvals;
 236
 237         devc = sdi->priv;
 238         acq  = devc->acquisition;
 239
 240         /* Reset RLE state. */
 241         acq->rle = RLE_STATE_DATA;
 242         acq->sample  = 0;
 243         acq->run_len = 0;
 244
 245         acq->samples_done = 0;
 246
 247         /* For some reason, the start address is 4 rather than 0. */
 248         acq->mem_addr_done = 4;
 249         acq->mem_addr_next = 4;
 250         acq->mem_addr_stop = acq->mem_addr_fill;
 251
 252         /* Sample position in the packet output buffer. */
 253         acq->out_index = 0;
 254
 255         regvals = devc->reg_write_seq;
 256
 257         regvals[0].reg = REG_DIV_BYPASS;
 258         regvals[0].val = 1;
 259
 260         regvals[1].reg = REG_MEM_CTRL2;
 261         regvals[1].val = 2;
 262
 263         regvals[2].reg = REG_MEM_CTRL4;
 264         regvals[2].val = 4;
 265
 266         devc->reg_write_pos = 0;
 267         devc->reg_write_len = 3;
 268
 269         if (issue_next_write_reg(sdi) == SR_OK)
 270                 devc->state = STATE_READ_PREPARE;
 271 }
 272
 273 /* Issue a command as an asynchronous USB transfer which returns the device
 274  * to normal state after a read operation.  Sets a new device context state
 275  * on success.
 276  */
 277 static void issue_read_end(const struct sr_dev_inst *sdi)
 278 {
 279         struct dev_context *devc;
 280
 281         devc = sdi->priv;
 282
 283         if (issue_write_reg(sdi, REG_DIV_BYPASS, 0) == SR_OK)
 284                 devc->state = STATE_READ_END;
 285 }
 286
 287 /* Decode an incoming response to a buffer fill level request and act on it
 288  * as appropriate.  Note that this function changes the device context state.
 289  */
 290 static void process_capture_length(const struct sr_dev_inst *sdi)
 291 {
 292         struct dev_context *devc;
 293         struct acquisition_state *acq;
 294
 295         devc = sdi->priv;
 296         acq  = devc->acquisition;
 297
 298         if (acq->xfer_in->actual_length != 4) {
 299                 sr_err("Received size %d doesn't match expected size 4.",
 300                        acq->xfer_in->actual_length);
 301                 devc->transfer_error = TRUE;
 302                 return;
 303         }
 304         acq->mem_addr_fill = LWLA_TO_UINT32(acq->xfer_buf_in[0]);
 305
 306         sr_dbg("%zu words in capture buffer.", acq->mem_addr_fill);
 307
 308         if (acq->mem_addr_fill > 0 && !devc->cancel_requested)
 309                 issue_read_start(sdi);
 310         else
 311                 issue_read_end(sdi);
 312 }
 313
 314 /* Initiate a sequence of register write commands with the effect of
 315  * cancelling a running capture operation.  This sets a new device state
 316  * if issuing the first command succeeds.
 317  */
 318 static void issue_stop_capture(const struct sr_dev_inst *sdi)
 319 {
 320         struct dev_context *devc;
 321         struct regval_pair *regvals;
 322
 323         devc = sdi->priv;
 324
 325         if (devc->stopping_in_progress)
 326                 return;
 327
 328         regvals = devc->reg_write_seq;
 329
 330         regvals[0].reg = REG_CMD_CTRL2;
 331         regvals[0].val = 10;
 332
 333         regvals[1].reg = REG_CMD_CTRL3;
 334         regvals[1].val = 0;
 335
 336         regvals[2].reg = REG_CMD_CTRL4;
 337         regvals[2].val = 0;
 338
 339         regvals[3].reg = REG_CMD_CTRL1;
 340         regvals[3].val = 0;
 341
 342         regvals[4].reg = REG_DIV_BYPASS;
 343         regvals[4].val = 0;
 344
 345         devc->reg_write_pos = 0;
 346         devc->reg_write_len = 5;
 347
 348         if (issue_next_write_reg(sdi) == SR_OK) {
 349                 devc->stopping_in_progress = TRUE;
 350                 devc->state = STATE_STOP_CAPTURE;
 351         }
 352 }
 353
 354 /* Decode an incoming capture status response and act on it as appropriate.
 355  * Note that this function changes the device state.
 356  */
 357 static void process_capture_status(const struct sr_dev_inst *sdi)
 358 {
 359         uint64_t duration;
 360         struct dev_context *devc;
 361         struct acquisition_state *acq;
 362         unsigned int mem_fill;
 363         unsigned int flags;
 364
 365         devc = sdi->priv;
 366         acq  = devc->acquisition;
 367
 368         if (acq->xfer_in->actual_length != CAP_STAT_LEN * 8) {
 369                 sr_err("Received size %d doesn't match expected size %d.",
 370                        acq->xfer_in->actual_length, CAP_STAT_LEN * 8);
 371                 devc->transfer_error = TRUE;
 372                 return;
 373         }
 374
 375         /* TODO: Find out the actual bit width of these fields as stored
 376          * in the FPGA.  These fields are definitely less than 64 bit wide
 377          * internally, and the unused bits occasionally even contain garbage.
 378          */
 379         mem_fill = LWLA_TO_UINT32(acq->xfer_buf_in[0]);
 380         duration = LWLA_TO_UINT32(acq->xfer_buf_in[4]);
 381         flags    = LWLA_TO_UINT32(acq->xfer_buf_in[8]) & STATUS_FLAG_MASK;
 382
 383         /* The LWLA1034 runs at 125 MHz if the clock divider is bypassed.
 384          * However, the time base used for the duration is apparently not
 385          * adjusted for this "boost" mode.  Whereas normally the duration
 386          * unit is 1 ms, it is 0.8 ms when the clock divider is bypassed.
 387          * As 0.8 = 100 MHz / 125 MHz, it seems that the internal cycle
 388          * counter period is the same as at the 100 MHz setting.
 389          */
 390         if (acq->bypass_clockdiv)
 391                 acq->duration_now = duration * 4 / 5;
 392         else
 393                 acq->duration_now = duration;
 394
 395         sr_spew("Captured %u words, %" PRIu64 " ms, flags 0x%02X.",
 396                 mem_fill, acq->duration_now, flags);
 397
 398         if ((flags & STATUS_TRIGGERED) > (acq->capture_flags & STATUS_TRIGGERED))
 399                 sr_info("Capture triggered.");
 400
 401         acq->capture_flags = flags;
 402
 403         if (acq->duration_now >= acq->duration_max) {
 404                 sr_dbg("Time limit reached, stopping capture.");
 405                 issue_stop_capture(sdi);
 406                 return;
 407         }
 408         devc->state = STATE_STATUS_WAIT;
 409
 410         if ((acq->capture_flags & STATUS_TRIGGERED) == 0) {
 411                 sr_spew("Waiting for trigger.");
 412         } else if ((acq->capture_flags & STATUS_MEM_AVAIL) == 0) {
 413                 sr_dbg("Capture memory filled.");
 414                 request_capture_length(sdi);
 415         } else if ((acq->capture_flags & STATUS_CAPTURING) != 0) {
 416                 sr_spew("Sampling in progress.");
 417         }
 418 }
 419
 420 /* Issue a capture buffer read request as an asynchronous USB transfer.
 421  * The address and size of the memory area to read are derived from the
 422  * current acquisition state.
 423  */
 424 static void request_read_mem(const struct sr_dev_inst *sdi)
 425 {
 426         struct dev_context *devc;
 427         struct acquisition_state *acq;
 428         size_t count;
 429
 430         devc = sdi->priv;
 431         acq  = devc->acquisition;
 432
 433         if (acq->mem_addr_next >= acq->mem_addr_stop)
 434                 return;
 435
 436         /* Always read a multiple of 8 device words. */
 437         count = (acq->mem_addr_stop - acq->mem_addr_next + 7) / 8 * 8;
 438         count = MIN(count, READ_CHUNK_LEN);
 439
 440         acq->xfer_buf_out[0] = LWLA_WORD(CMD_READ_MEM);
 441         acq->xfer_buf_out[1] = LWLA_WORD_0(acq->mem_addr_next);
 442         acq->xfer_buf_out[2] = LWLA_WORD_1(acq->mem_addr_next);
 443         acq->xfer_buf_out[3] = LWLA_WORD_0(count);
 444         acq->xfer_buf_out[4] = LWLA_WORD_1(count);
 445
 446         acq->xfer_out->length = 5 * sizeof(uint16_t);
 447
 448         if (submit_transfer(devc, acq->xfer_out) == SR_OK) {
 449                 acq->mem_addr_next += count;
 450                 devc->state = STATE_READ_REQUEST;
 451         }
 452 }
 453
 454 /* Demangle and decompress incoming sample data from the capture buffer.
 455  * The data chunk is taken from the acquisition state, and is expected to
 456  * contain a multiple of 8 device words.
 457  * All data currently in the acquisition buffer will be processed.  Packets
 458  * of decoded samples are sent off to the session bus whenever the output
 459  * buffer becomes full while decoding.
 460  */
 461 static int process_sample_data(const struct sr_dev_inst *sdi)
 462 {
 463         uint64_t sample;
 464         uint64_t high_nibbles;
 465         uint64_t word;
 466         struct dev_context *devc;
 467         struct acquisition_state *acq;
 468         uint8_t *out_p;
 469         uint32_t *slice;
 470         struct sr_datafeed_packet packet;
 471         struct sr_datafeed_logic logic;
 472         size_t expect_len;
 473         size_t actual_len;
 474         size_t out_max_samples;
 475         size_t out_run_samples;
 476         size_t ri;
 477         size_t in_words_left;
 478         size_t si;
 479
 480         devc = sdi->priv;
 481         acq  = devc->acquisition;
 482
 483         if (acq->mem_addr_done >= acq->mem_addr_stop
 484                         || acq->samples_done >= acq->samples_max)
 485                 return SR_OK;
 486
 487         in_words_left = MIN(acq->mem_addr_stop - acq->mem_addr_done,
 488                             READ_CHUNK_LEN);
 489         expect_len = LWLA1034_MEMBUF_LEN(in_words_left) * sizeof(uint32_t);
 490         actual_len = acq->xfer_in->actual_length;
 491
 492         if (actual_len != expect_len) {
 493                 sr_err("Received size %zu does not match expected size %zu.",
 494                        actual_len, expect_len);
 495                 devc->transfer_error = TRUE;
 496                 return SR_ERR;
 497         }
 498         acq->mem_addr_done += in_words_left;
 499
 500         /* Prepare session packet. */
 501         packet.type    = SR_DF_LOGIC;
 502         packet.payload = &logic;
 503         logic.unitsize = UNIT_SIZE;
 504         logic.data     = acq->out_packet;
 505
 506         slice = acq->xfer_buf_in;
 507         si = 0; /* word index within slice */
 508
 509         for (;;) {
 510                 /* Calculate number of samples to write into packet. */
 511                 out_max_samples = MIN(acq->samples_max - acq->samples_done,
 512                                       PACKET_LENGTH - acq->out_index);
 513                 out_run_samples = MIN(acq->run_len, out_max_samples);
 514
 515                 /* Expand run-length samples into session packet. */
 516                 sample = acq->sample;
 517                 out_p = &acq->out_packet[acq->out_index * UNIT_SIZE];
 518
 519                 for (ri = 0; ri < out_run_samples; ++ri) {
 520                         out_p[0] =  sample        & 0xFF;
 521                         out_p[1] = (sample >>  8) & 0xFF;
 522                         out_p[2] = (sample >> 16) & 0xFF;
 523                         out_p[3] = (sample >> 24) & 0xFF;
 524                         out_p[4] = (sample >> 32) & 0xFF;
 525                         out_p += UNIT_SIZE;
 526                 }
 527                 acq->run_len -= out_run_samples;
 528                 acq->out_index += out_run_samples;
 529                 acq->samples_done += out_run_samples;
 530
 531                 /* Packet full or sample count limit reached? */
 532                 if (out_run_samples == out_max_samples) {
 533                         logic.length = acq->out_index * UNIT_SIZE;
 534                         sr_session_send(sdi, &packet);
 535                         acq->out_index = 0;
 536
 537                         if (acq->samples_done >= acq->samples_max)
 538                                 return SR_OK; /* sample limit reached */
 539                         if (acq->run_len > 0)
 540                                 continue; /* need another packet */
 541                 }
 542
 543                 if (in_words_left == 0)
 544                         break; /* done with current chunk */
 545
 546                 /* Now work on the current slice. */
 547                 high_nibbles = LWLA_TO_UINT32(slice[8]);
 548                 word = LWLA_TO_UINT32(slice[si]);
 549                 word |= (high_nibbles << (4 * si + 4)) & ((uint64_t)0xF << 32);
 550
 551                 if (acq->rle == RLE_STATE_DATA) {
 552                         acq->sample = word & ALL_CHANNELS_MASK;
 553                         acq->run_len = ((word >> NUM_CHANNELS) & 1) + 1;
 554                         if (word & RLE_FLAG_LEN_FOLLOWS)
 555                                 acq->rle = RLE_STATE_LEN;
 556                 } else {
 557                         acq->run_len += word << 1;
 558                         acq->rle = RLE_STATE_DATA;
 559                 }
 560
 561                 /* Move to next word. */
 562                 si = (si + 1) % 8;
 563                 if (si == 0)
 564                         slice += 9;
 565                 --in_words_left;
 566         }
 567
 568         /* Send out partially filled packet if this was the last chunk. */
 569         if (acq->mem_addr_done >= acq->mem_addr_stop && acq->out_index > 0) {
 570                 logic.length = acq->out_index * UNIT_SIZE;
 571                 sr_session_send(sdi, &packet);
 572                 acq->out_index = 0;
 573         }
 574         return SR_OK;
 575 }
 576
 577 /* Finish an acquisition session.  This sends the end packet to the session
 578  * bus and removes the listener for asynchronous USB transfers.
 579  */
 580 static void end_acquisition(struct sr_dev_inst *sdi)
 581 {
 582         struct drv_context *drvc;
 583         struct dev_context *devc;
 584         struct sr_datafeed_packet packet;
 585
 586         drvc = sdi->driver->context;
 587         devc = sdi->priv;
 588
 589         if (devc->state == STATE_IDLE)
 590                 return;
 591
 592         devc->state = STATE_IDLE;
 593
 594         /* Remove USB file descriptors from polling. */
 595         usb_source_remove(sdi->session, drvc->sr_ctx);
 596
 597         packet.type = SR_DF_END;
 598         sr_session_send(sdi, &packet);
 599
 600         lwla_free_acquisition_state(devc->acquisition);
 601         devc->acquisition = NULL;
 602         devc->cancel_requested = FALSE;
 603 }
 604
 605 /* USB output transfer completion callback.
 606  */
 607 static void LIBUSB_CALL receive_transfer_out(struct libusb_transfer *transfer)
 608 {
 609         struct sr_dev_inst *sdi;
 610         struct dev_context *devc;
 611
 612         sdi  = transfer->user_data;
 613         devc = sdi->priv;
 614
 615         if (transfer->status != LIBUSB_TRANSFER_COMPLETED) {
 616                 sr_err("Transfer to device failed: %d.", transfer->status);
 617                 devc->transfer_error = TRUE;
 618                 return;
 619         }
 620
 621         if (devc->reg_write_pos < devc->reg_write_len) {
 622                 issue_next_write_reg(sdi);
 623         } else {
 624                 switch (devc->state) {
 625                 case STATE_START_CAPTURE:
 626                         devc->state = STATE_STATUS_WAIT;
 627                         break;
 628                 case STATE_STATUS_REQUEST:
 629                         devc->state = STATE_STATUS_RESPONSE;
 630                         submit_transfer(devc, devc->acquisition->xfer_in);
 631                         break;
 632                 case STATE_STOP_CAPTURE:
 633                         if (!devc->cancel_requested)
 634                                 request_capture_length(sdi);
 635                         else
 636                                 end_acquisition(sdi);
 637                         break;
 638                 case STATE_LENGTH_REQUEST:
 639                         devc->state = STATE_LENGTH_RESPONSE;
 640                         submit_transfer(devc, devc->acquisition->xfer_in);
 641                         break;
 642                 case STATE_READ_PREPARE:
 643                         request_read_mem(sdi);
 644                         break;
 645                 case STATE_READ_REQUEST:
 646                         devc->state = STATE_READ_RESPONSE;
 647                         submit_transfer(devc, devc->acquisition->xfer_in);
 648                         break;
 649                 case STATE_READ_END:
 650                         end_acquisition(sdi);
 651                         break;
 652                 default:
 653                         sr_err("Unexpected device state %d.", devc->state);
 654                         break;
 655                 }
 656         }
 657 }
 658
 659 /* USB input transfer completion callback.
 660  */
 661 static void LIBUSB_CALL receive_transfer_in(struct libusb_transfer *transfer)
 662 {
 663         struct sr_dev_inst *sdi;
 664         struct dev_context *devc;
 665         struct acquisition_state *acq;
 666
 667         sdi  = transfer->user_data;
 668         devc = sdi->priv;
 669         acq  = devc->acquisition;
 670
 671         if (transfer->status != LIBUSB_TRANSFER_COMPLETED) {
 672                 sr_err("Transfer from device failed: %d.", transfer->status);
 673                 devc->transfer_error = TRUE;
 674                 return;
 675         }
 676
 677         switch (devc->state) {
 678         case STATE_STATUS_RESPONSE:
 679                 process_capture_status(sdi);
 680                 break;
 681         case STATE_LENGTH_RESPONSE:
 682                 process_capture_length(sdi);
 683                 break;
 684         case STATE_READ_RESPONSE:
 685                 if (process_sample_data(sdi) == SR_OK
 686                                 && acq->mem_addr_next < acq->mem_addr_stop
 687                                 && acq->samples_done < acq->samples_max)
 688                         request_read_mem(sdi);
 689                 else
 690                         issue_read_end(sdi);
 691                 break;
 692         default:
 693                 sr_err("Unexpected device state %d.", devc->state);
 694                 break;
 695         }
 696 }
 697
 698 /* Initialize the LWLA.  This downloads a bitstream into the FPGA
 699  * and executes a simple device test sequence.
 700  */
 701 SR_PRIV int lwla_init_device(const struct sr_dev_inst *sdi)
 702 {
 703         struct dev_context *devc;
 704         int ret;
 705         uint32_t value;
 706
 707         devc = sdi->priv;
 708
 709         /* Force reload of bitstream */
 710         devc->cur_clock_config = CONF_CLOCK_NONE;
 711
 712         ret = lwla_set_clock_config(sdi);
 713
 714         if (ret != SR_OK)
 715                 return ret;
 716
 717         ret = lwla_write_reg(sdi->conn, REG_CMD_CTRL2, 100);
 718         if (ret != SR_OK)
 719                 return ret;
 720
 721         ret = lwla_read_reg(sdi->conn, REG_CMD_CTRL1, &value);
 722         if (ret != SR_OK)
 723                 return ret;
 724         sr_dbg("Received test word 0x%08X back.", value);
 725         if (value != 0x12345678)
 726                 return SR_ERR;
 727
 728         ret = lwla_read_reg(sdi->conn, REG_CMD_CTRL4, &value);
 729         if (ret != SR_OK)
 730                 return ret;
 731         sr_dbg("Received test word 0x%08X back.", value);
 732         if (value != 0x12345678)
 733                 return SR_ERR;
 734
 735         ret = lwla_read_reg(sdi->conn, REG_CMD_CTRL3, &value);
 736         if (ret != SR_OK)
 737                 return ret;
 738         sr_dbg("Received test word 0x%08X back.", value);
 739         if (value != 0x87654321)
 740                 return SR_ERR;
 741
 742         return ret;
 743 }
 744
 745 /* Select the LWLA clock configuration.  If the clock source changed from
 746  * the previous setting, this will download a new bitstream to the FPGA.
 747  */
 748 SR_PRIV int lwla_set_clock_config(const struct sr_dev_inst *sdi)
 749 {
 750         struct dev_context *devc;
 751         int ret;
 752         enum clock_config choice;
 753
 754         devc = sdi->priv;
 755
 756         if (sdi->status == SR_ST_INACTIVE)
 757                 choice = CONF_CLOCK_NONE;
 758         else if (devc->cfg_clock_source == CLOCK_INTERNAL)
 759                 choice = CONF_CLOCK_INT;
 760         else if (devc->cfg_clock_edge == EDGE_POSITIVE)
 761                 choice = CONF_CLOCK_EXT_RISE;
 762         else
 763                 choice = CONF_CLOCK_EXT_FALL;
 764
 765         if (choice != devc->cur_clock_config) {
 766                 devc->cur_clock_config = CONF_CLOCK_NONE;
 767                 ret = lwla_send_bitstream(sdi->conn, bitstream_map[choice]);
 768                 if (ret == SR_OK)
 769                         devc->cur_clock_config = choice;
 770                 return ret;
 771         }
 772         return SR_OK;
 773 }
 774
 775 /* Configure the LWLA in preparation for an acquisition session.
 776  */
 777 SR_PRIV int lwla_setup_acquisition(const struct sr_dev_inst *sdi)
 778 {
 779         struct dev_context *devc;
 780         struct sr_usb_dev_inst *usb;
 781         struct acquisition_state *acq;
 782         struct regval_pair regvals[7];
 783         int ret;
 784
 785         devc = sdi->priv;
 786         usb  = sdi->conn;
 787         acq  = devc->acquisition;
 788
 789         if (devc->limit_msec > 0) {
 790                 acq->duration_max = devc->limit_msec;
 791                 sr_info("Acquisition time limit %" PRIu64 " ms.",
 792                         devc->limit_msec);
 793         } else
 794                 acq->duration_max = MAX_LIMIT_MSEC;
 795
 796         if (devc->limit_samples > 0) {
 797                 acq->samples_max = devc->limit_samples;
 798                 sr_info("Acquisition sample count limit %" PRIu64 ".",
 799                         devc->limit_samples);
 800         } else
 801                 acq->samples_max = MAX_LIMIT_SAMPLES;
 802
 803         if (devc->cfg_clock_source == CLOCK_INTERNAL) {
 804                 sr_info("Internal clock, samplerate %" PRIu64 ".",
 805                         devc->samplerate);
 806                 if (devc->samplerate == 0)
 807                         return SR_ERR_BUG;
 808                 /* At 125 MHz, the clock divider is bypassed. */
 809                 acq->bypass_clockdiv = (devc->samplerate > SR_MHZ(100));
 810
 811                 /* If only one of the limits is set, derive the other one. */
 812                 if (devc->limit_msec == 0 && devc->limit_samples > 0)
 813                         acq->duration_max = devc->limit_samples
 814                                         * 1000 / devc->samplerate + 1;
 815                 else if (devc->limit_samples == 0 && devc->limit_msec > 0)
 816                         acq->samples_max = devc->limit_msec
 817                                         * devc->samplerate / 1000;
 818         } else {
 819                 acq->bypass_clockdiv = TRUE;
 820
 821                 if (devc->cfg_clock_edge == EDGE_NEGATIVE)
 822                         sr_info("External clock, falling edge.");
 823                 else
 824                         sr_info("External clock, rising edge.");
 825         }
 826
 827         regvals[0].reg = REG_MEM_CTRL2;
 828         regvals[0].val = 2;
 829
 830         regvals[1].reg = REG_MEM_CTRL2;
 831         regvals[1].val = 1;
 832
 833         regvals[2].reg = REG_CMD_CTRL2;
 834         regvals[2].val = 10;
 835
 836         regvals[3].reg = REG_CMD_CTRL3;
 837         regvals[3].val = 0x74;
 838
 839         regvals[4].reg = REG_CMD_CTRL4;
 840         regvals[4].val = 0;
 841
 842         regvals[5].reg = REG_CMD_CTRL1;
 843         regvals[5].val = 0;
 844
 845         regvals[6].reg = REG_DIV_BYPASS;
 846         regvals[6].val = acq->bypass_clockdiv;
 847
 848         ret = lwla_write_regs(usb, regvals, ARRAY_SIZE(regvals));
 849         if (ret != SR_OK)
 850                 return ret;
 851
 852         return capture_setup(sdi);
 853 }
 854
 855 /* Start the capture operation on the LWLA device.  Beginning with this
 856  * function, all USB transfers will be asynchronous until the end of the
 857  * acquisition session.
 858  */
 859 SR_PRIV int lwla_start_acquisition(const struct sr_dev_inst *sdi)
 860 {
 861         struct dev_context *devc;
 862         struct sr_usb_dev_inst *usb;
 863         struct acquisition_state *acq;
 864         struct regval_pair *regvals;
 865
 866         devc = sdi->priv;
 867         usb  = sdi->conn;
 868         acq  = devc->acquisition;
 869
 870         acq->duration_now  = 0;
 871         acq->mem_addr_fill = 0;
 872         acq->capture_flags = 0;
 873
 874         libusb_fill_bulk_transfer(acq->xfer_out, usb->devhdl, EP_COMMAND,
 875                                   (unsigned char *)acq->xfer_buf_out, 0,
 876                                   &receive_transfer_out,
 877                                   (struct sr_dev_inst *)sdi, USB_TIMEOUT_MS);
 878
 879         libusb_fill_bulk_transfer(acq->xfer_in, usb->devhdl, EP_REPLY,
 880                                   (unsigned char *)acq->xfer_buf_in,
 881                                   sizeof acq->xfer_buf_in,
 882                                   &receive_transfer_in,
 883                                   (struct sr_dev_inst *)sdi, USB_TIMEOUT_MS);
 884
 885         regvals = devc->reg_write_seq;
 886
 887         regvals[0].reg = REG_CMD_CTRL2;
 888         regvals[0].val = 10;
 889
 890         regvals[1].reg = REG_CMD_CTRL3;
 891         regvals[1].val = 1;
 892
 893         regvals[2].reg = REG_CMD_CTRL4;
 894         regvals[2].val = 0;
 895
 896         regvals[3].reg = REG_CMD_CTRL1;
 897         regvals[3].val = 0;
 898
 899         devc->reg_write_pos = 0;
 900         devc->reg_write_len = 4;
 901
 902         devc->state = STATE_START_CAPTURE;
 903
 904         return issue_next_write_reg(sdi);
 905 }
 906
 907 /* Allocate an acquisition state object.
 908  */
 909 SR_PRIV struct acquisition_state *lwla_alloc_acquisition_state(void)
 910 {
 911         struct acquisition_state *acq;
 912
 913         acq = g_malloc0(sizeof(struct acquisition_state));
 914
 915         acq->xfer_in = libusb_alloc_transfer(0);
 916         if (!acq->xfer_in) {
 917                 sr_err("Transfer malloc failed.");
 918                 g_free(acq);
 919                 return NULL;
 920         }
 921
 922         acq->xfer_out = libusb_alloc_transfer(0);
 923         if (!acq->xfer_out) {
 924                 sr_err("Transfer malloc failed.");
 925                 libusb_free_transfer(acq->xfer_in);
 926                 g_free(acq);
 927                 return NULL;
 928         }
 929
 930         return acq;
 931 }
 932
 933 /* Deallocate an acquisition state object.
 934  */
 935 SR_PRIV void lwla_free_acquisition_state(struct acquisition_state *acq)
 936 {
 937         if (acq) {
 938                 libusb_free_transfer(acq->xfer_out);
 939                 libusb_free_transfer(acq->xfer_in);
 940                 g_free(acq);
 941         }
 942 }
 943
 944 /* USB I/O source callback.
 945  */
 946 SR_PRIV int lwla_receive_data(int fd, int revents, void *cb_data)
 947 {
 948         struct sr_dev_inst *sdi;
 949         struct dev_context *devc;
 950         struct drv_context *drvc;
 951         struct timeval tv;
 952         int ret;
 953
 954         (void)fd;
 955
 956         sdi  = cb_data;
 957         devc = sdi->priv;
 958         drvc = sdi->driver->context;
 959
 960         if (!devc || !drvc)
 961                 return FALSE;
 962
 963         /* No timeout: return immediately. */
 964         tv.tv_sec  = 0;
 965         tv.tv_usec = 0;
 966
 967         ret = libusb_handle_events_timeout_completed(drvc->sr_ctx->libusb_ctx,
 968                                                      &tv, NULL);
 969         if (ret != 0)
 970                 sr_err("Event handling failed: %s.", libusb_error_name(ret));
 971
 972         /* If no event flags are set the timeout must have expired. */
 973         if (revents == 0 && devc->state == STATE_STATUS_WAIT) {
 974                 if (devc->cancel_requested)
 975                         issue_stop_capture(sdi);
 976                 else
 977                         request_capture_status(sdi);
 978         }
 979
 980         /* Check if an error occurred on a transfer. */
 981         if (devc->transfer_error)
 982                 end_acquisition(sdi);
 983
 984         return TRUE;
 985 }