git.sur5r.net Git - openocd/blob - src/jtag/jlink.c

   1 /***************************************************************************
   2  *   Copyright (C) 2007 by Juergen Stuber <juergen@jstuber.net>            *
   3  *   based on Dominic Rath's and Benedikt Sauter's usbprog.c               *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program; if not, write to the                         *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  19  ***************************************************************************/
  20
  21 #ifdef HAVE_CONFIG_H
  22 #include "config.h"
  23 #endif
  24
  25 #include "replacements.h"
  26
  27 #include "jtag.h"
  28
  29 #include <usb.h>
  30 #include <string.h>
  31
  32 #include "log.h"
  33
  34 /* enable this to debug communication
  35  */
  36 #if 0
  37 #define _DEBUG_USB_COMMS_
  38 #endif
  39
  40 #ifdef _DEBUG_JTAG_IO_
  41 #define DEBUG_JTAG_IO(expr ...) LOG_DEBUG(expr)
  42 #else
  43 #define DEBUG_JTAG_IO(expr ...)
  44 #endif
  45
  46 #define VID 0x1366
  47 #define PID 0x0101
  48
  49 #define JLINK_WRITE_ENDPOINT    0x02
  50 #define JLINK_READ_ENDPOINT             0x81
  51
  52 #define JLINK_USB_TIMEOUT               100
  53
  54 #define JLINK_IN_BUFFER_SIZE    2064
  55 #define JLINK_OUT_BUFFER_SIZE   2064
  56
  57 /* Global USB buffers */
  58 static u8 usb_in_buffer[JLINK_IN_BUFFER_SIZE];
  59 static u8 usb_out_buffer[JLINK_OUT_BUFFER_SIZE];
  60
  61 /* Constants for JLink command */
  62 #define JLINK_FIRMWARE_VERSION                  0x01
  63 #define JLINK_SPEED_COMMAND                             0x05
  64 #define JLINK_GET_STATUS_COMMAND                0x07
  65 #define JLINK_TAP_SEQUENCE_COMMAND              0xcd
  66 #define JLINK_GET_SERIAL                                0xe6
  67 #define JLINK_SET_SRST_LOW_COMMAND              0xdc
  68 #define JLINK_SET_SRST_HIGH_COMMAND             0xdd
  69 #define JLINK_SET_TRST_LOW_COMMAND              0xde
  70 #define JLINK_SET_TRST_HIGH_COMMAND             0xdf
  71 #define JLINK_HARDWARE_VERSION                  0xe8
  72
  73 /* max speed 12MHz v5.0 jlink */
  74 #define JLINK_MAX_SPEED 12000
  75
  76 /* External interface functions */
  77 int jlink_execute_queue(void);
  78 int jlink_speed(int speed);
  79 int jlink_khz(int khz, int *jtag_speed);
  80 int jlink_register_commands(struct command_context_s *cmd_ctx);
  81 int jlink_init(void);
  82 int jlink_quit(void);
  83
  84 /* CLI command handler functions */
  85 int jlink_handle_jlink_info_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
  86
  87 /* Queue command functions */
  88 void jlink_end_state(enum tap_state state);
  89 void jlink_state_move(void);
  90 void jlink_path_move(int num_states, enum tap_state *path);
  91 void jlink_runtest(int num_cycles);
  92 void jlink_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size, scan_command_t *command);
  93 void jlink_reset(int trst, int srst);
  94 void jlink_simple_command(u8 command);
  95 int jlink_get_status(void);
  96
  97 /* J-Link tap buffer functions */
  98 void jlink_tap_init();
  99 int jlink_tap_execute();
 100 void jlink_tap_ensure_space(int scans, int bits);
 101 void jlink_tap_append_step(int tms, int tdi);
 102 void jlink_tap_append_scan(int length, u8 *buffer, scan_command_t *command);
 103
 104 /* Jlink lowlevel functions */
 105 typedef struct jlink_jtag
 106 {
 107         struct usb_dev_handle* usb_handle;
 108 } jlink_jtag_t;
 109
 110 jlink_jtag_t *jlink_usb_open(void);
 111 void jlink_usb_close(jlink_jtag_t *jlink_jtag);
 112 int jlink_usb_message(jlink_jtag_t *jlink_jtag, int out_length, int in_length);
 113 int jlink_usb_write(jlink_jtag_t *jlink_jtag, int out_length);
 114 int jlink_usb_read(jlink_jtag_t *jlink_jtag);
 115
 116 #ifdef _DEBUG_USB_COMMS_
 117 void jlink_debug_buffer(u8 *buffer, int length);
 118 #endif
 119
 120 jlink_jtag_t* jlink_jtag_handle;
 121
 122 /***************************************************************************/
 123 /* External interface implementation */
 124
 125 jtag_interface_t jlink_interface =
 126 {
 127         .name = "jlink",
 128         .execute_queue = jlink_execute_queue,
 129         .speed = jlink_speed,
 130         .khz = jlink_khz,
 131         .register_commands = jlink_register_commands,
 132         .init = jlink_init,
 133         .quit = jlink_quit
 134 };
 135
 136 int jlink_execute_queue(void)
 137 {
 138         jtag_command_t *cmd = jtag_command_queue;
 139         int scan_size;
 140         enum scan_type type;
 141         u8 *buffer;
 142
 143         while (cmd != NULL)
 144         {
 145                 switch (cmd->type)
 146                 {
 147                         case JTAG_END_STATE:
 148                                 DEBUG_JTAG_IO("end_state: %i", cmd->cmd.end_state->end_state);
 149
 150                                 if (cmd->cmd.end_state->end_state != -1)
 151                                 {
 152                                         jlink_end_state(cmd->cmd.end_state->end_state);
 153                                 }
 154                                 break;
 155
 156                         case JTAG_RUNTEST:
 157                                 DEBUG_JTAG_IO( "runtest %i cycles, end in %i", cmd->cmd.runtest->num_cycles, \
 158                                         cmd->cmd.runtest->end_state);
 159
 160                                 if (cmd->cmd.runtest->end_state != -1)
 161                                 {
 162                                         jlink_end_state(cmd->cmd.runtest->end_state);
 163                                 }
 164                                 jlink_runtest(cmd->cmd.runtest->num_cycles);
 165                                 break;
 166
 167                         case JTAG_STATEMOVE:
 168                                 DEBUG_JTAG_IO("statemove end in %i",
 169                                 cmd->cmd.statemove->end_state);
 170
 171                                 if (cmd->cmd.statemove->end_state != -1)
 172                                 {
 173                                         jlink_end_state(cmd->cmd.statemove->end_state);
 174                                 }
 175                                 jlink_state_move();
 176                                 break;
 177
 178                         case JTAG_PATHMOVE:
 179                             DEBUG_JTAG_IO("pathmove: %i states, end in %i",
 180                                 cmd->cmd.pathmove->num_states,
 181                                 cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]);
 182
 183                                 jlink_path_move(cmd->cmd.pathmove->num_states, cmd->cmd.pathmove->path);
 184                                 break;
 185
 186                         case JTAG_SCAN:
 187                                 DEBUG_JTAG_IO("scan end in %i", cmd->cmd.scan->end_state);
 188
 189                                 if (cmd->cmd.scan->end_state != -1)
 190                                 {
 191                                     jlink_end_state(cmd->cmd.scan->end_state);
 192                                 }
 193
 194                                 scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
 195                                 DEBUG_JTAG_IO("scan input, length = %d", scan_size);
 196
 197 #ifdef _DEBUG_USB_COMMS_
 198                                 jlink_debug_buffer(buffer, (scan_size + 7) / 8);
 199 #endif
 200                                 type = jtag_scan_type(cmd->cmd.scan);
 201                                 jlink_scan(cmd->cmd.scan->ir_scan, type, buffer, scan_size, cmd->cmd.scan);
 202                                 break;
 203
 204                         case JTAG_RESET:
 205                                 DEBUG_JTAG_IO("reset trst: %i srst %i",
 206                                 cmd->cmd.reset->trst,
 207                                 cmd->cmd.reset->srst);
 208
 209                                 jlink_tap_execute();
 210
 211                                 if (cmd->cmd.reset->trst == 1)
 212                                 {
 213                                         cur_state = TAP_TLR;
 214                                 }
 215                                 jlink_reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
 216                                 break;
 217
 218                         case JTAG_SLEEP:
 219                                 DEBUG_JTAG_IO("sleep %i", cmd->cmd.sleep->us);
 220                                 jlink_tap_execute();
 221                                 jtag_sleep(cmd->cmd.sleep->us);
 222                                 break;
 223
 224                 default:
 225                         LOG_ERROR("BUG: unknown JTAG command type encountered");
 226                         exit(-1);
 227                 }
 228                 cmd = cmd->next;
 229         }
 230         jlink_tap_execute();
 231
 232         return ERROR_OK;
 233 }
 234
 235 /* Sets speed in kHz. */
 236 int jlink_speed(int speed)
 237 {
 238         int result;
 239
 240 //      if ((speed == -1) || ((1 <= speed) && (speed <= JLINK_MAX_SPEED)))
 241         if (speed <= JLINK_MAX_SPEED)
 242         {
 243                 /* check for RTCK setting */
 244                 if (speed == 0)
 245                         speed = -1;
 246
 247                 usb_out_buffer[0] = JLINK_SPEED_COMMAND;
 248                 usb_out_buffer[1] = (speed >> 0) & 0xff;
 249                 usb_out_buffer[2] = (speed >> 8) & 0xff;
 250
 251                 result = jlink_usb_write(jlink_jtag_handle, 3);
 252
 253                 if (result == 3)
 254                 {
 255                         return ERROR_OK;
 256                 }
 257                 else
 258                 {
 259                         LOG_ERROR("J-Link setting speed failed (%d)", result);
 260                         return ERROR_JTAG_DEVICE_ERROR;
 261                 }
 262         }
 263         else
 264         {
 265                 LOG_INFO("Requested speed %dkHz exceeds maximum of %dkHz, ignored", speed, JLINK_MAX_SPEED);
 266         }
 267
 268         return ERROR_OK;
 269 }
 270
 271 int jlink_khz(int khz, int *jtag_speed)
 272 {
 273         *jtag_speed = khz;
 274
 275         return ERROR_OK;
 276 }
 277
 278 int jlink_register_commands(struct command_context_s *cmd_ctx)
 279 {
 280         register_command(cmd_ctx, NULL, "jlink_info", jlink_handle_jlink_info_command, COMMAND_EXEC,
 281                 "query jlink info");
 282         return ERROR_OK;
 283 }
 284
 285 int jlink_init(void)
 286 {
 287         int result;
 288
 289         jlink_jtag_handle = jlink_usb_open();
 290
 291         if (jlink_jtag_handle == 0)
 292         {
 293                 LOG_ERROR("Can't find USB JTAG Interface! Please check connection and permissions.");
 294                 return ERROR_JTAG_INIT_FAILED;
 295         }
 296
 297         result = jlink_usb_read(jlink_jtag_handle);
 298         if (result != 2 || usb_in_buffer[0] != 0x07 || usb_in_buffer[1] != 0x00)
 299         {
 300                 LOG_INFO("J-Link initial read failed, don't worry");
 301         }
 302
 303         LOG_INFO("J-Link JTAG Interface ready");
 304
 305         jlink_reset(0, 0);
 306         jlink_tap_init();
 307
 308         /* query jlink status */
 309         jlink_get_status();
 310
 311         return ERROR_OK;
 312 }
 313
 314 int jlink_quit(void)
 315 {
 316         jlink_usb_close(jlink_jtag_handle);
 317         return ERROR_OK;
 318 }
 319
 320 /***************************************************************************/
 321 /* Queue command implementations */
 322
 323 void jlink_end_state(enum tap_state state)
 324 {
 325         if (tap_move_map[state] != -1)
 326         {
 327                 end_state = state;
 328         }
 329         else
 330         {
 331                 LOG_ERROR("BUG: %i is not a valid end state", state);
 332                 exit(-1);
 333         }
 334 }
 335
 336 /* Goes to the end state. */
 337 void jlink_state_move(void)
 338 {
 339         int i;
 340         int tms = 0;
 341         u8 tms_scan = TAP_MOVE(cur_state, end_state);
 342
 343         for (i = 0; i < 7; i++)
 344         {
 345                 tms = (tms_scan >> i) & 1;
 346                 jlink_tap_append_step(tms, 0);
 347         }
 348
 349         cur_state = end_state;
 350 }
 351
 352 void jlink_path_move(int num_states, enum tap_state *path)
 353 {
 354         int i;
 355
 356         for (i = 0; i < num_states; i++)
 357         {
 358                 if (path[i] == tap_transitions[cur_state].low)
 359                 {
 360                         jlink_tap_append_step(0, 0);
 361                 }
 362                 else if (path[i] == tap_transitions[cur_state].high)
 363                 {
 364                         jlink_tap_append_step(1, 0);
 365                 }
 366                 else
 367                 {
 368                         LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition", tap_state_strings[cur_state], tap_state_strings[path[i]]);
 369                         exit(-1);
 370                 }
 371
 372                 cur_state = path[i];
 373         }
 374
 375         end_state = cur_state;
 376 }
 377
 378 void jlink_runtest(int num_cycles)
 379 {
 380         int i;
 381
 382         enum tap_state saved_end_state = end_state;
 383
 384         /* only do a state_move when we're not already in RTI */
 385         if (cur_state != TAP_RTI)
 386         {
 387                 jlink_end_state(TAP_RTI);
 388                 jlink_state_move();
 389         }
 390
 391         /* execute num_cycles */
 392         for (i = 0; i < num_cycles; i++)
 393         {
 394                 jlink_tap_append_step(0, 0);
 395         }
 396
 397         /* finish in end_state */
 398         jlink_end_state(saved_end_state);
 399         if (cur_state != end_state)
 400         {
 401                 jlink_state_move();
 402         }
 403 }
 404
 405 void jlink_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size, scan_command_t *command)
 406 {
 407         enum tap_state saved_end_state;
 408
 409         jlink_tap_ensure_space(1, scan_size + 8);
 410
 411         saved_end_state = end_state;
 412
 413         /* Move to appropriate scan state */
 414         jlink_end_state(ir_scan ? TAP_SI : TAP_SD);
 415
 416         jlink_state_move();
 417         jlink_end_state(saved_end_state);
 418
 419         /* Scan */
 420         jlink_tap_append_scan(scan_size, buffer, command);
 421
 422         /* We are in Exit1, go to Pause */
 423         jlink_tap_append_step(0, 0);
 424
 425         cur_state = ir_scan ? TAP_PI : TAP_PD;
 426
 427         if (cur_state != end_state)
 428         {
 429                 jlink_state_move();
 430         }
 431 }
 432
 433 void jlink_reset(int trst, int srst)
 434 {
 435         LOG_DEBUG("trst: %i, srst: %i", trst, srst);
 436
 437         /* Signals are active low */
 438         if (trst == 0)
 439         {
 440                 jlink_simple_command(JLINK_SET_TRST_HIGH_COMMAND);
 441         }
 442         else if (trst == 1)
 443         {
 444                 jlink_simple_command(JLINK_SET_TRST_LOW_COMMAND);
 445         }
 446
 447         if (srst == 0)
 448         {
 449                 jlink_simple_command(JLINK_SET_SRST_HIGH_COMMAND);
 450         }
 451         else if (srst == 1)
 452         {
 453                 jlink_simple_command(JLINK_SET_SRST_LOW_COMMAND);
 454         }
 455 }
 456
 457 void jlink_simple_command(u8 command)
 458 {
 459         int result;
 460
 461         DEBUG_JTAG_IO("0x%02x", command);
 462
 463         usb_out_buffer[0] = command;
 464         result = jlink_usb_write(jlink_jtag_handle, 1);
 465
 466         if (result != 1)
 467         {
 468                 LOG_ERROR("J-Link command 0x%02x failed (%d)", command, result);
 469         }
 470 }
 471
 472 int jlink_get_status(void)
 473 {
 474         int result;
 475
 476         jlink_simple_command(JLINK_GET_STATUS_COMMAND);
 477         result = jlink_usb_read(jlink_jtag_handle);
 478
 479         if(result == 8)
 480         {
 481                 int vref = usb_in_buffer[0] + (usb_in_buffer[1] << 8);
 482                 LOG_INFO("Vref = %d.%d TCK=%d TDI=%d TDO=%d TMS=%d SRST=%d TRST=%d\n", \
 483                         vref / 1000, vref % 1000, \
 484                         usb_in_buffer[2], usb_in_buffer[3], usb_in_buffer[4], \
 485                         usb_in_buffer[5], usb_in_buffer[6], usb_in_buffer[7]);
 486
 487                 if(vref < 1500)
 488                 {
 489                         LOG_ERROR("Vref too low. Eventually the target isn't powered or disconnected?\n");
 490                 }
 491         }
 492         else
 493         {
 494                 LOG_ERROR("J-Link command JLINK_GET_STATUS_COMMAND failed (%d)\n", result);
 495         }
 496
 497         return ERROR_OK;
 498 }
 499
 500 int jlink_handle_jlink_info_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
 501 {
 502         int result;
 503         int len = 0;
 504
 505         /* query hardware version */
 506         jlink_simple_command(JLINK_FIRMWARE_VERSION);
 507         result = jlink_usb_read(jlink_jtag_handle);
 508
 509         if (result == 2)
 510         {
 511                 len = buf_get_u32(usb_in_buffer, 0, 16);
 512                 result = jlink_usb_read(jlink_jtag_handle);
 513
 514                 if(result == len)
 515                 {
 516                         usb_in_buffer[result] = 0;
 517                         LOG_INFO(usb_in_buffer);
 518                 }
 519
 520                 /* attempt to get status */
 521                 jlink_get_status();
 522         }
 523         else
 524         {
 525                 LOG_ERROR("J-Link command JLINK_FIRMWARE_VERSION failed (%d)\n", result);
 526         }
 527
 528         return ERROR_OK;
 529 }
 530
 531 /***************************************************************************/
 532 /* J-Link tap functions */
 533
 534 /* We use the maximal value observed */
 535 #define JLINK_TAP_BUFFER_SIZE 390
 536
 537 static int tap_length;
 538 static u8 tms_buffer[JLINK_TAP_BUFFER_SIZE];
 539 static u8 tdi_buffer[JLINK_TAP_BUFFER_SIZE];
 540 static u8 tdo_buffer[JLINK_TAP_BUFFER_SIZE];
 541
 542 typedef struct
 543 {
 544         int first;      /* First bit position in tdo_buffer to read */
 545         int length; /* Number of bits to read */
 546         scan_command_t *command; /* Corresponding scan command */
 547         u8 *buffer;
 548 } pending_scan_result_t;
 549
 550 #define MAX_PENDING_SCAN_RESULTS 16
 551
 552 static int pending_scan_results_length;
 553 static pending_scan_result_t pending_scan_results_buffer[MAX_PENDING_SCAN_RESULTS];
 554
 555 static int last_tms;
 556
 557 void jlink_tap_init()
 558 {
 559         tap_length = 0;
 560         pending_scan_results_length = 0;
 561 }
 562
 563 void jlink_tap_ensure_space(int scans, int bits)
 564 {
 565         int available_scans = MAX_PENDING_SCAN_RESULTS - pending_scan_results_length;
 566         int available_bits = JLINK_TAP_BUFFER_SIZE * 8 - tap_length;
 567
 568         if (scans > available_scans || bits > available_bits)
 569         {
 570                 jlink_tap_execute();
 571         }
 572 }
 573
 574 void jlink_tap_append_step(int tms, int tdi)
 575 {
 576         last_tms = tms;
 577         int index = tap_length / 8;
 578
 579         if (index < JLINK_TAP_BUFFER_SIZE)
 580         {
 581                 int bit_index = tap_length % 8;
 582                 u8 bit = 1 << bit_index;
 583
 584                 if (tms)
 585                 {
 586                         tms_buffer[index] |= bit;
 587                 }
 588                 else
 589                 {
 590                         tms_buffer[index] &= ~bit;
 591                 }
 592
 593                 if (tdi)
 594                 {
 595                         tdi_buffer[index] |= bit;
 596                 }
 597                 else
 598                 {
 599                         tdi_buffer[index] &= ~bit;
 600                 }
 601
 602                 tap_length++;
 603         }
 604         else
 605         {
 606                 LOG_ERROR("jlink_tap_append_step, overflow");
 607         }
 608 }
 609
 610 void jlink_tap_append_scan(int length, u8 *buffer, scan_command_t *command)
 611 {
 612         pending_scan_result_t *pending_scan_result = &pending_scan_results_buffer[pending_scan_results_length];
 613         int i;
 614
 615         pending_scan_result->first = tap_length;
 616         pending_scan_result->length = length;
 617         pending_scan_result->command = command;
 618         pending_scan_result->buffer = buffer;
 619
 620         for (i = 0; i < length; i++)
 621         {
 622                 jlink_tap_append_step((i < length-1 ? 0 : 1), (buffer[i/8] >> (i%8)) & 1);
 623         }
 624         pending_scan_results_length++;
 625 }
 626
 627 /* Pad and send a tap sequence to the device, and receive the answer.
 628  * For the purpose of padding we assume that we are in idle or pause state. */
 629 int jlink_tap_execute()
 630 {
 631         int byte_length;
 632         int tms_offset;
 633         int tdi_offset;
 634         int i;
 635         int result;
 636
 637         if (tap_length > 0)
 638         {
 639                 /* Pad last byte so that tap_length is divisible by 8 */
 640                 while (tap_length % 8 != 0)
 641                 {
 642                         /* More of the last TMS value keeps us in the same state,
 643                          * analogous to free-running JTAG interfaces. */
 644                         jlink_tap_append_step(last_tms, 0);
 645                 }
 646
 647                 byte_length = tap_length / 8;
 648
 649                 usb_out_buffer[0] = JLINK_TAP_SEQUENCE_COMMAND;
 650                 usb_out_buffer[1] = (tap_length >> 0) & 0xff;
 651                 usb_out_buffer[2] = (tap_length >> 8) & 0xff;
 652
 653                 tms_offset = 3;
 654                 for (i = 0; i < byte_length; i++)
 655                 {
 656                     usb_out_buffer[tms_offset + i] = tms_buffer[i];
 657                 }
 658
 659                 tdi_offset = tms_offset + byte_length;
 660                 for (i = 0; i < byte_length; i++)
 661                 {
 662                     usb_out_buffer[tdi_offset + i] = tdi_buffer[i];
 663                 }
 664
 665                 result = jlink_usb_message(jlink_jtag_handle, 3 + 2 * byte_length, byte_length);
 666
 667                 if (result == byte_length)
 668                 {
 669                         for (i = 0; i < byte_length; i++)
 670                         {
 671                                 tdo_buffer[i] = usb_in_buffer[i];
 672                         }
 673
 674                         for (i = 0; i < pending_scan_results_length; i++)
 675                         {
 676                                 pending_scan_result_t *pending_scan_result = &pending_scan_results_buffer[i];
 677                                 u8 *buffer = pending_scan_result->buffer;
 678                                 int length = pending_scan_result->length;
 679                                 int first = pending_scan_result->first;
 680                                 scan_command_t *command = pending_scan_result->command;
 681
 682                                 /* Copy to buffer */
 683                                 buf_set_buf(tdo_buffer, first, buffer, 0, length);
 684
 685                                 DEBUG_JTAG_IO("pending scan result, length = %d", length);
 686
 687 #ifdef _DEBUG_USB_COMMS_
 688                                 jlink_debug_buffer(buffer, byte_length);
 689 #endif
 690
 691                         if (jtag_read_buffer(buffer, command) != ERROR_OK)
 692                         {
 693                                 jlink_tap_init();
 694                                         return ERROR_JTAG_QUEUE_FAILED;
 695                         }
 696
 697                         if (pending_scan_result->buffer != NULL)
 698                         {
 699                                         free(pending_scan_result->buffer);
 700                         }
 701                 }
 702                 }
 703                 else
 704                 {
 705                         LOG_ERROR("jlink_tap_execute, wrong result %d, expected %d", result, byte_length);
 706                         return ERROR_JTAG_QUEUE_FAILED;
 707                 }
 708
 709                 jlink_tap_init();
 710         }
 711
 712         return ERROR_OK;
 713 }
 714
 715 /*****************************************************************************/
 716 /* JLink USB low-level functions */
 717
 718 jlink_jtag_t* jlink_usb_open()
 719 {
 720         struct usb_bus *busses;
 721         struct usb_bus *bus;
 722         struct usb_device *dev;
 723
 724         jlink_jtag_t *result;
 725
 726         result = (jlink_jtag_t*) malloc(sizeof(jlink_jtag_t));
 727
 728         usb_init();
 729         usb_find_busses();
 730         usb_find_devices();
 731
 732         busses = usb_get_busses();
 733
 734         /* find jlink_jtag device in usb bus */
 735
 736         for (bus = busses; bus; bus = bus->next)
 737         {
 738                 for (dev = bus->devices; dev; dev = dev->next)
 739                 {
 740                         if ((dev->descriptor.idVendor == VID) && (dev->descriptor.idProduct == PID))
 741                         {
 742                                 result->usb_handle = usb_open(dev);
 743
 744                                 /* usb_set_configuration required under win32 */
 745                                 usb_set_configuration(result->usb_handle, dev->config[0].bConfigurationValue);
 746                                 usb_claim_interface(result->usb_handle, 0);
 747                                 usb_set_altinterface(result->usb_handle, 0);
 748                                 return result;
 749                         }
 750                 }
 751         }
 752
 753         free(result);
 754         return NULL;
 755 }
 756
 757 void jlink_usb_close(jlink_jtag_t *jlink_jtag)
 758 {
 759         usb_close(jlink_jtag->usb_handle);
 760         free(jlink_jtag);
 761 }
 762
 763 /* Send a message and receive the reply. */
 764 int jlink_usb_message(jlink_jtag_t *jlink_jtag, int out_length, int in_length)
 765 {
 766         int result;
 767
 768         result = jlink_usb_write(jlink_jtag, out_length);
 769         if (result == out_length)
 770         {
 771                 result = jlink_usb_read(jlink_jtag);
 772                 if (result == in_length)
 773                 {
 774                         return result;
 775                 }
 776             else
 777             {
 778                         LOG_ERROR("usb_bulk_read failed (requested=%d, result=%d)", in_length, result);
 779                         return -1;
 780             }
 781         }
 782         else
 783         {
 784                 LOG_ERROR("usb_bulk_write failed (requested=%d, result=%d)", out_length, result);
 785             return -1;
 786         }
 787 }
 788
 789 /* Write data from out_buffer to USB. */
 790 int jlink_usb_write(jlink_jtag_t *jlink_jtag, int out_length)
 791 {
 792         int result;
 793
 794         if (out_length > JLINK_OUT_BUFFER_SIZE)
 795         {
 796                 LOG_ERROR("jlink_jtag_write illegal out_length=%d (max=%d)", out_length, JLINK_OUT_BUFFER_SIZE);
 797                 return -1;
 798         }
 799
 800         result = usb_bulk_write(jlink_jtag->usb_handle, JLINK_WRITE_ENDPOINT, \
 801                 usb_out_buffer, out_length, JLINK_USB_TIMEOUT);
 802
 803         DEBUG_JTAG_IO("jlink_usb_write, out_length = %d, result = %d", out_length, result);
 804
 805 #ifdef _DEBUG_USB_COMMS_
 806         jlink_debug_buffer(usb_out_buffer, out_length);
 807 #endif
 808         return result;
 809 }
 810
 811 /* Read data from USB into in_buffer. */
 812 int jlink_usb_read(jlink_jtag_t *jlink_jtag)
 813 {
 814         int result = usb_bulk_read(jlink_jtag->usb_handle, JLINK_READ_ENDPOINT, \
 815                 usb_in_buffer, JLINK_IN_BUFFER_SIZE, JLINK_USB_TIMEOUT);
 816
 817         DEBUG_JTAG_IO("jlink_usb_read, result = %d", result);
 818
 819 #ifdef _DEBUG_USB_COMMS_
 820         jlink_debug_buffer(usb_in_buffer, result);
 821 #endif
 822     return result;
 823 }
 824
 825 #ifdef _DEBUG_USB_COMMS_
 826 #define BYTES_PER_LINE  16
 827
 828 void jlink_debug_buffer(u8 *buffer, int length)
 829 {
 830         char line[81];
 831         char s[4];
 832         int i;
 833         int j;
 834
 835         for (i = 0; i < length; i += BYTES_PER_LINE)
 836         {
 837                 snprintf(line, 5, "%04x", i);
 838                 for (j = i; j < i + BYTES_PER_LINE && j < length; j++)
 839                 {
 840                         snprintf(s, 4, " %02x", buffer[j]);
 841                         strcat(line, s);
 842                 }
 843                 LOG_DEBUG(line);
 844         }
 845 }
 846 #endif