src/jtag/drivers/arm-jtag-ew.c

   1 /***************************************************************************
   2  *   Copyright (C) 2009 by Dimitar Dimitrov <dinuxbg@gmail.com>            *
   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 <jtag/interface.h>
  26 #include <jtag/commands.h>
  27 #include <usb.h>
  28 #include "usb_common.h"
  29
  30 #define USB_VID                                         0x15ba
  31 #define USB_PID                                         0x001e
  32
  33 #define ARMJTAGEW_EPT_BULK_OUT          0x01u
  34 #define ARMJTAGEW_EPT_BULK_IN           0x82u
  35
  36 #define ARMJTAGEW_USB_TIMEOUT           2000
  37
  38 #define ARMJTAGEW_IN_BUFFER_SIZE        (4*1024)
  39 #define ARMJTAGEW_OUT_BUFFER_SIZE       (4*1024)
  40
  41 /* USB command request codes. */
  42 #define CMD_GET_VERSION                         0x00
  43 #define CMD_SELECT_DPIMPL                       0x10
  44 #define CMD_SET_TCK_FREQUENCY           0x11
  45 #define CMD_GET_TCK_FREQUENCY           0x12
  46 #define CMD_MEASURE_MAX_TCK_FREQ        0x15
  47 #define CMD_MEASURE_RTCK_RESPONSE       0x16
  48 #define CMD_TAP_SHIFT                           0x17
  49 #define CMD_SET_TAPHW_STATE                     0x20
  50 #define CMD_GET_TAPHW_STATE                     0x21
  51 #define CMD_TGPWR_SETUP                         0x22
  52
  53 /* Global USB buffers */
  54 static uint8_t usb_in_buffer[ARMJTAGEW_IN_BUFFER_SIZE];
  55 static uint8_t usb_out_buffer[ARMJTAGEW_OUT_BUFFER_SIZE];
  56
  57 /* Queue command functions */
  58 static void armjtagew_end_state(tap_state_t state);
  59 static void armjtagew_state_move(void);
  60 static void armjtagew_path_move(int num_states, tap_state_t *path);
  61 static void armjtagew_runtest(int num_cycles);
  62 static void armjtagew_scan(bool ir_scan, enum scan_type type, uint8_t *buffer, int scan_size, struct scan_command *command);
  63 static void armjtagew_reset(int trst, int srst);
  64 //static void armjtagew_simple_command(uint8_t command);
  65 static int armjtagew_get_status(void);
  66
  67 /* tap buffer functions */
  68 static void armjtagew_tap_init(void);
  69 static int armjtagew_tap_execute(void);
  70 static void armjtagew_tap_ensure_space(int scans, int bits);
  71 static void armjtagew_tap_append_step(int tms, int tdi);
  72 static void armjtagew_tap_append_scan(int length, uint8_t *buffer, struct scan_command *command);
  73
  74 /* ARM-JTAG-EW lowlevel functions */
  75 struct armjtagew {
  76         struct usb_dev_handle* usb_handle;
  77 };
  78
  79 static struct armjtagew *armjtagew_usb_open(void);
  80 static void armjtagew_usb_close(struct armjtagew *armjtagew);
  81 static int armjtagew_usb_message(struct armjtagew *armjtagew, int out_length, int in_length);
  82 static int armjtagew_usb_write(struct armjtagew *armjtagew, int out_length);
  83 static int armjtagew_usb_read(struct armjtagew *armjtagew, int exp_in_length);
  84
  85 /* helper functions */
  86 static int armjtagew_get_version_info(void);
  87
  88 #ifdef _DEBUG_USB_COMMS_
  89 static void armjtagew_debug_buffer(uint8_t *buffer, int length);
  90 #endif
  91
  92 static struct armjtagew* armjtagew_handle;
  93
  94 /***************************************************************************/
  95 /* External interface implementation */
  96
  97 static int armjtagew_execute_queue(void)
  98 {
  99         struct jtag_command *cmd = jtag_command_queue;
 100         int scan_size;
 101         enum scan_type type;
 102         uint8_t *buffer;
 103
 104         while (cmd != NULL)
 105         {
 106                 switch (cmd->type)
 107                 {
 108                         case JTAG_RUNTEST:
 109                                 DEBUG_JTAG_IO("runtest %i cycles, end in %i", cmd->cmd.runtest->num_cycles, \
 110                                         cmd->cmd.runtest->end_state);
 111
 112                                 armjtagew_end_state(cmd->cmd.runtest->end_state);
 113                                 armjtagew_runtest(cmd->cmd.runtest->num_cycles);
 114                                 break;
 115
 116                         case JTAG_TLR_RESET:
 117                                 DEBUG_JTAG_IO("statemove end in %i", cmd->cmd.statemove->end_state);
 118
 119                                 armjtagew_end_state(cmd->cmd.statemove->end_state);
 120                                 armjtagew_state_move();
 121                                 break;
 122
 123                         case JTAG_PATHMOVE:
 124                                 DEBUG_JTAG_IO("pathmove: %i states, end in %i", \
 125                                         cmd->cmd.pathmove->num_states, \
 126                                         cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]);
 127
 128                                 armjtagew_path_move(cmd->cmd.pathmove->num_states, cmd->cmd.pathmove->path);
 129                                 break;
 130
 131                         case JTAG_SCAN:
 132                                 DEBUG_JTAG_IO("scan end in %i", cmd->cmd.scan->end_state);
 133
 134                                 armjtagew_end_state(cmd->cmd.scan->end_state);
 135
 136                                 scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
 137                                 DEBUG_JTAG_IO("scan input, length = %d", scan_size);
 138
 139 #ifdef _DEBUG_USB_COMMS_
 140                                 armjtagew_debug_buffer(buffer, (scan_size + 7) / 8);
 141 #endif
 142                                 type = jtag_scan_type(cmd->cmd.scan);
 143                                 armjtagew_scan(cmd->cmd.scan->ir_scan, type, buffer, scan_size, cmd->cmd.scan);
 144                                 break;
 145
 146                         case JTAG_RESET:
 147                                 DEBUG_JTAG_IO("reset trst: %i srst %i", cmd->cmd.reset->trst, cmd->cmd.reset->srst);
 148
 149                                 armjtagew_tap_execute();
 150
 151                                 if (cmd->cmd.reset->trst == 1)
 152                                 {
 153                                         tap_set_state(TAP_RESET);
 154                                 }
 155                                 armjtagew_reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
 156                                 break;
 157
 158                         case JTAG_SLEEP:
 159                                 DEBUG_JTAG_IO("sleep %i", cmd->cmd.sleep->us);
 160                                 armjtagew_tap_execute();
 161                                 jtag_sleep(cmd->cmd.sleep->us);
 162                                 break;
 163
 164                         default:
 165                                 LOG_ERROR("BUG: unknown JTAG command type encountered");
 166                                 exit(-1);
 167                 }
 168                 cmd = cmd->next;
 169         }
 170
 171         return armjtagew_tap_execute();
 172 }
 173
 174 /* Sets speed in kHz. */
 175 static int armjtagew_speed(int speed)
 176 {
 177         int result;
 178         int speed_real;
 179
 180
 181         usb_out_buffer[0] = CMD_SET_TCK_FREQUENCY;
 182         buf_set_u32(usb_out_buffer + 1, 0, 32, speed*1000);
 183
 184         result = armjtagew_usb_message(armjtagew_handle, 5, 4);
 185
 186         if (result < 0)
 187         {
 188                 LOG_ERROR("ARM-JTAG-EW setting speed failed (%d)", result);
 189                 return ERROR_JTAG_DEVICE_ERROR;
 190         }
 191
 192         usb_out_buffer[0] = CMD_GET_TCK_FREQUENCY;
 193         result = armjtagew_usb_message(armjtagew_handle, 1, 4);
 194         speed_real = (int)buf_get_u32(usb_in_buffer, 0, 32) / 1000;
 195         if (result < 0)
 196         {
 197                 LOG_ERROR("ARM-JTAG-EW getting speed failed (%d)", result);
 198                 return ERROR_JTAG_DEVICE_ERROR;
 199         }
 200         else
 201         {
 202                 LOG_INFO("Requested speed %dkHz, emulator reported %dkHz.", speed, speed_real);
 203         }
 204
 205         return ERROR_OK;
 206 }
 207
 208 static int armjtagew_khz(int khz, int *jtag_speed)
 209 {
 210         *jtag_speed = khz;
 211
 212         return ERROR_OK;
 213 }
 214
 215 static int armjtagew_speed_div(int speed, int* khz)
 216 {
 217         *khz = speed;
 218
 219         return ERROR_OK;
 220 }
 221
 222 static int armjtagew_init(void)
 223 {
 224         int check_cnt;
 225
 226         armjtagew_handle = armjtagew_usb_open();
 227
 228         if (armjtagew_handle == 0)
 229         {
 230                 LOG_ERROR("Cannot find ARM-JTAG-EW Interface! Please check connection and permissions.");
 231                 return ERROR_JTAG_INIT_FAILED;
 232         }
 233
 234         check_cnt = 0;
 235         while (check_cnt < 3)
 236         {
 237                 if (armjtagew_get_version_info() == ERROR_OK)
 238                 {
 239                         /* attempt to get status */
 240                         armjtagew_get_status();
 241                         break;
 242                 }
 243
 244                 check_cnt++;
 245         }
 246
 247         if (check_cnt == 3)
 248         {
 249                 LOG_INFO("ARM-JTAG-EW initial read failed, don't worry");
 250         }
 251
 252         /* Initial JTAG speed (for reset and initialization): 32 kHz */
 253         armjtagew_speed(32);
 254
 255         LOG_INFO("ARM-JTAG-EW JTAG Interface ready");
 256
 257         armjtagew_reset(0, 0);
 258         armjtagew_tap_init();
 259
 260         return ERROR_OK;
 261 }
 262
 263 static int armjtagew_quit(void)
 264 {
 265         armjtagew_usb_close(armjtagew_handle);
 266         return ERROR_OK;
 267 }
 268
 269 /***************************************************************************/
 270 /* Queue command implementations */
 271
 272 static void armjtagew_end_state(tap_state_t state)
 273 {
 274         if (tap_is_state_stable(state))
 275         {
 276                 tap_set_end_state(state);
 277         }
 278         else
 279         {
 280                 LOG_ERROR("BUG: %i is not a valid end state", state);
 281                 exit(-1);
 282         }
 283 }
 284
 285 /* Goes to the end state. */
 286 static void armjtagew_state_move(void)
 287 {
 288         int i;
 289         int tms = 0;
 290         uint8_t tms_scan = tap_get_tms_path(tap_get_state(), tap_get_end_state());
 291         int tms_count = tap_get_tms_path_len(tap_get_state(), tap_get_end_state());
 292
 293         for (i = 0; i < tms_count; i++)
 294         {
 295                 tms = (tms_scan >> i) & 1;
 296                 armjtagew_tap_append_step(tms, 0);
 297         }
 298
 299         tap_set_state(tap_get_end_state());
 300 }
 301
 302 static void armjtagew_path_move(int num_states, tap_state_t *path)
 303 {
 304         int i;
 305
 306         for (i = 0; i < num_states; i++)
 307         {
 308                 /*
 309                  * TODO: The ARM-JTAG-EW hardware delays TDI with 3 TCK cycles when in RTCK mode.
 310                  * Either handle that here, or update the documentation with examples
 311                  * how to fix that in the configuration files.
 312                  */
 313                 if (path[i] == tap_state_transition(tap_get_state(), false))
 314                 {
 315                         armjtagew_tap_append_step(0, 0);
 316                 }
 317                 else if (path[i] == tap_state_transition(tap_get_state(), true))
 318                 {
 319                         armjtagew_tap_append_step(1, 0);
 320                 }
 321                 else
 322                 {
 323                         LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition", tap_state_name(tap_get_state()), tap_state_name(path[i]));
 324                         exit(-1);
 325                 }
 326
 327                 tap_set_state(path[i]);
 328         }
 329
 330         tap_set_end_state(tap_get_state());
 331 }
 332
 333 static void armjtagew_runtest(int num_cycles)
 334 {
 335         int i;
 336
 337         tap_state_t saved_end_state = tap_get_end_state();
 338
 339         /* only do a state_move when we're not already in IDLE */
 340         if (tap_get_state() != TAP_IDLE)
 341         {
 342                 armjtagew_end_state(TAP_IDLE);
 343                 armjtagew_state_move();
 344         }
 345
 346         /* execute num_cycles */
 347         for (i = 0; i < num_cycles; i++)
 348         {
 349                 armjtagew_tap_append_step(0, 0);
 350         }
 351
 352         /* finish in end_state */
 353         armjtagew_end_state(saved_end_state);
 354         if (tap_get_state() != tap_get_end_state())
 355         {
 356                 armjtagew_state_move();
 357         }
 358 }
 359
 360 static void armjtagew_scan(bool ir_scan, enum scan_type type, uint8_t *buffer, int scan_size, struct scan_command *command)
 361 {
 362         tap_state_t saved_end_state;
 363
 364         armjtagew_tap_ensure_space(1, scan_size + 8);
 365
 366         saved_end_state = tap_get_end_state();
 367
 368         /* Move to appropriate scan state */
 369         armjtagew_end_state(ir_scan ? TAP_IRSHIFT : TAP_DRSHIFT);
 370
 371         armjtagew_state_move();
 372         armjtagew_end_state(saved_end_state);
 373
 374         /* Scan */
 375         armjtagew_tap_append_scan(scan_size, buffer, command);
 376
 377         /* We are in Exit1, go to Pause */
 378         armjtagew_tap_append_step(0, 0);
 379
 380         tap_set_state(ir_scan ? TAP_IRPAUSE : TAP_DRPAUSE);
 381
 382         if (tap_get_state() != tap_get_end_state())
 383         {
 384                 armjtagew_state_move();
 385         }
 386 }
 387
 388 static void armjtagew_reset(int trst, int srst)
 389 {
 390         const uint8_t trst_mask = (1u << 5);
 391         const uint8_t srst_mask = (1u << 6);
 392         uint8_t val = 0;
 393         uint8_t outp_en = 0;
 394         uint8_t change_mask = 0;
 395         int result;
 396
 397         LOG_DEBUG("trst: %i, srst: %i", trst, srst);
 398
 399         if (srst == 0)
 400         {
 401                 val |= srst_mask;
 402                 outp_en &= ~srst_mask;          /* tristate */
 403                 change_mask |= srst_mask;
 404         }
 405         else if (srst == 1)
 406         {
 407                 val &= ~srst_mask;
 408                 outp_en |= srst_mask;
 409                 change_mask |= srst_mask;
 410         }
 411
 412         if (trst == 0)
 413         {
 414                 val |= trst_mask;
 415                 outp_en &= ~trst_mask;          /* tristate */
 416                 change_mask |= trst_mask;
 417         }
 418         else if (trst == 1)
 419         {
 420                 val &= ~trst_mask;
 421                 outp_en |= trst_mask;
 422                 change_mask |= trst_mask;
 423         }
 424
 425         usb_out_buffer[0] = CMD_SET_TAPHW_STATE;
 426         usb_out_buffer[1] = val;
 427         usb_out_buffer[2] = outp_en;
 428         usb_out_buffer[3] = change_mask;
 429         result = armjtagew_usb_write(armjtagew_handle, 4);
 430         if (result != 4)
 431         {
 432                 LOG_ERROR("ARM-JTAG-EW TRST/SRST pin set failed failed (%d)", result);
 433         }
 434 }
 435
 436 static int armjtagew_get_status(void)
 437 {
 438         int result;
 439
 440         usb_out_buffer[0] = CMD_GET_TAPHW_STATE;
 441         result = armjtagew_usb_message(armjtagew_handle, 1, 12);
 442
 443         if (result == 0)
 444         {
 445                 unsigned int u_tg = buf_get_u32(usb_in_buffer, 0, 16);
 446                 LOG_INFO("U_tg = %d mV, U_aux = %d mV, U_tgpwr = %d mV, I_tgpwr = %d mA, D1 = %d, Target power %s %s",
 447                          (int)(buf_get_u32(usb_in_buffer + 0, 0, 16)),
 448                          (int)(buf_get_u32(usb_in_buffer + 2, 0, 16)),
 449                          (int)(buf_get_u32(usb_in_buffer + 4, 0, 16)),
 450                          (int)(buf_get_u32(usb_in_buffer + 6, 0, 16)),
 451                          usb_in_buffer[9],
 452                          usb_in_buffer[11] ? "OVERCURRENT" : "OK",
 453                          usb_in_buffer[10] ? "enabled" : "disabled");
 454
 455                 if (u_tg < 1500)
 456                 {
 457                         LOG_ERROR("Vref too low. Check Target Power");
 458                 }
 459         }
 460         else
 461         {
 462                 LOG_ERROR("ARM-JTAG-EW command CMD_GET_TAPHW_STATE failed (%d)", result);
 463         }
 464
 465         return ERROR_OK;
 466 }
 467
 468 static int armjtagew_get_version_info(void)
 469 {
 470         int result;
 471         char sn[16];
 472         char auxinfo[257];
 473
 474         /* query hardware version */
 475         usb_out_buffer[0] = CMD_GET_VERSION;
 476         result = armjtagew_usb_message(armjtagew_handle, 1, 4 + 15 + 256);
 477
 478         if (result != 0)
 479         {
 480                 LOG_ERROR("ARM-JTAG-EW command CMD_GET_VERSION failed (%d)", result);
 481                 return ERROR_JTAG_DEVICE_ERROR;
 482         }
 483
 484
 485         memcpy(sn, usb_in_buffer + 4, 15);
 486         sn[15] = '\0';
 487         memcpy(auxinfo, usb_in_buffer + 4+15, 256);
 488         auxinfo[256] = '\0';
 489
 490         LOG_INFO("ARM-JTAG-EW firmware version %d.%d, hardware revision %c, SN=%s, Additional info: %s", \
 491                         usb_in_buffer[1], usb_in_buffer[0], \
 492                         isgraph(usb_in_buffer[2]) ? usb_in_buffer[2] : 'X', \
 493                         sn, auxinfo);
 494
 495         if (1 != usb_in_buffer[1] || 6 != usb_in_buffer[0])
 496         {
 497                 LOG_WARNING("ARM-JTAG-EW firmware version %d.%d is untested with this version of OpenOCD. You might experience unexpected behavior.", usb_in_buffer[1], usb_in_buffer[0]);
 498         }
 499         return ERROR_OK;
 500 }
 501
 502 COMMAND_HANDLER(armjtagew_handle_armjtagew_info_command)
 503 {
 504         if (armjtagew_get_version_info() == ERROR_OK)
 505         {
 506                 /* attempt to get status */
 507                 armjtagew_get_status();
 508         }
 509
 510         return ERROR_OK;
 511 }
 512
 513 static const struct command_registration armjtagew_command_handlers[] = {
 514         {
 515                 .name = "armjtagew_info",
 516                 .handler = &armjtagew_handle_armjtagew_info_command,
 517                 .mode = COMMAND_EXEC,
 518                 .help = "query armjtagew info",
 519         },
 520         COMMAND_REGISTRATION_DONE
 521 };
 522
 523 struct jtag_interface armjtagew_interface = {
 524         .name = "arm-jtag-ew",
 525         .commands = armjtagew_command_handlers,
 526         .transports = jtag_only,
 527         .execute_queue = armjtagew_execute_queue,
 528         .speed = armjtagew_speed,
 529         .speed_div = armjtagew_speed_div,
 530         .khz = armjtagew_khz,
 531         .init = armjtagew_init,
 532         .quit = armjtagew_quit,
 533 };
 534
 535 /***************************************************************************/
 536 /* ARM-JTAG-EW tap functions */
 537
 538 /* 2048 is the max value we can use here */
 539 #define ARMJTAGEW_TAP_BUFFER_SIZE 2048
 540
 541 static int tap_length;
 542 static uint8_t tms_buffer[ARMJTAGEW_TAP_BUFFER_SIZE];
 543 static uint8_t tdi_buffer[ARMJTAGEW_TAP_BUFFER_SIZE];
 544 static uint8_t tdo_buffer[ARMJTAGEW_TAP_BUFFER_SIZE];
 545
 546 struct pending_scan_result {
 547         int first;      /* First bit position in tdo_buffer to read */
 548         int length; /* Number of bits to read */
 549         struct scan_command *command; /* Corresponding scan command */
 550         uint8_t *buffer;
 551 };
 552
 553 #define MAX_PENDING_SCAN_RESULTS 256
 554
 555 static int pending_scan_results_length;
 556 static struct pending_scan_result pending_scan_results_buffer[MAX_PENDING_SCAN_RESULTS];
 557
 558 static int last_tms;
 559
 560 static void armjtagew_tap_init(void)
 561 {
 562         tap_length = 0;
 563         pending_scan_results_length = 0;
 564 }
 565
 566 static void armjtagew_tap_ensure_space(int scans, int bits)
 567 {
 568         int available_scans = MAX_PENDING_SCAN_RESULTS - pending_scan_results_length;
 569         int available_bits = ARMJTAGEW_TAP_BUFFER_SIZE * 8 - tap_length;
 570
 571         if (scans > available_scans || bits > available_bits)
 572         {
 573                 armjtagew_tap_execute();
 574         }
 575 }
 576
 577 static void armjtagew_tap_append_step(int tms, int tdi)
 578 {
 579         last_tms = tms;
 580         int index_local = tap_length / 8;
 581
 582         if (index_local < ARMJTAGEW_TAP_BUFFER_SIZE)
 583         {
 584                 int bit_index = tap_length % 8;
 585                 uint8_t bit = 1 << bit_index;
 586
 587                 if (tms)
 588                 {
 589                         tms_buffer[index_local] |= bit;
 590                 }
 591                 else
 592                 {
 593                         tms_buffer[index_local] &= ~bit;
 594                 }
 595
 596                 if (tdi)
 597                 {
 598                         tdi_buffer[index_local] |= bit;
 599                 }
 600                 else
 601                 {
 602                         tdi_buffer[index_local] &= ~bit;
 603                 }
 604
 605                 tap_length++;
 606         }
 607         else
 608         {
 609                 LOG_ERROR("armjtagew_tap_append_step, overflow");
 610         }
 611 }
 612
 613 void armjtagew_tap_append_scan(int length, uint8_t *buffer, struct scan_command *command)
 614 {
 615         struct pending_scan_result *pending_scan_result = &pending_scan_results_buffer[pending_scan_results_length];
 616         int i;
 617
 618         pending_scan_result->first = tap_length;
 619         pending_scan_result->length = length;
 620         pending_scan_result->command = command;
 621         pending_scan_result->buffer = buffer;
 622
 623         for (i = 0; i < length; i++)
 624         {
 625                 armjtagew_tap_append_step((i < length-1 ? 0 : 1), (buffer[i/8] >> (i%8)) & 1);
 626         }
 627         pending_scan_results_length++;
 628 }
 629
 630 /* Pad and send a tap sequence to the device, and receive the answer.
 631  * For the purpose of padding we assume that we are in idle or pause state. */
 632 static int armjtagew_tap_execute(void)
 633 {
 634         int byte_length;
 635         int tms_offset;
 636         int tdi_offset;
 637         int i;
 638         int result;
 639
 640         if (tap_length > 0)
 641         {
 642                 /* Pad last byte so that tap_length is divisible by 8 */
 643                 while (tap_length % 8 != 0)
 644                 {
 645                         /* More of the last TMS value keeps us in the same state,
 646                          * analogous to free-running JTAG interfaces. */
 647                         armjtagew_tap_append_step(last_tms, 0);
 648                 }
 649
 650                 byte_length = tap_length / 8;
 651
 652                 usb_out_buffer[0] = CMD_TAP_SHIFT;
 653                 buf_set_u32(usb_out_buffer + 1, 0, 16, byte_length);
 654
 655                 tms_offset = 3;
 656                 for (i = 0; i < byte_length; i++)
 657                 {
 658                         usb_out_buffer[tms_offset + i] = flip_u32(tms_buffer[i],8);
 659                 }
 660
 661                 tdi_offset = tms_offset + byte_length;
 662                 for (i = 0; i < byte_length; i++)
 663                 {
 664                         usb_out_buffer[tdi_offset + i] = flip_u32(tdi_buffer[i],8);
 665                 }
 666
 667                 result = armjtagew_usb_message(armjtagew_handle, 3 + 2 * byte_length, byte_length + 4);
 668
 669                 if (result == 0)
 670                 {
 671                         int stat_local;
 672
 673                         stat_local = (int)buf_get_u32(usb_in_buffer + byte_length, 0, 32);
 674                         if (stat_local) {
 675                                 LOG_ERROR("armjtagew_tap_execute, emulator returned error code %d for a CMD_TAP_SHIFT command", stat_local);
 676                                 return ERROR_JTAG_QUEUE_FAILED;
 677                         }
 678
 679                         for (i = 0; i < byte_length; i++)
 680                         {
 681                                 tdo_buffer[i] = flip_u32(usb_in_buffer[i],8);
 682                         }
 683
 684                         for (i = 0; i < pending_scan_results_length; i++)
 685                         {
 686                                 struct pending_scan_result *pending_scan_result = &pending_scan_results_buffer[i];
 687                                 uint8_t *buffer = pending_scan_result->buffer;
 688                                 int length = pending_scan_result->length;
 689                                 int first = pending_scan_result->first;
 690                                 struct scan_command *command = pending_scan_result->command;
 691
 692                                 /* Copy to buffer */
 693                                 buf_set_buf(tdo_buffer, first, buffer, 0, length);
 694
 695                                 DEBUG_JTAG_IO("pending scan result, length = %d", length);
 696
 697 #ifdef _DEBUG_USB_COMMS_
 698                                 armjtagew_debug_buffer(buffer, byte_length);
 699 #endif
 700
 701                                 if (jtag_read_buffer(buffer, command) != ERROR_OK)
 702                                 {
 703                                         armjtagew_tap_init();
 704                                         return ERROR_JTAG_QUEUE_FAILED;
 705                                 }
 706
 707                                 if (pending_scan_result->buffer != NULL)
 708                                 {
 709                                         free(pending_scan_result->buffer);
 710                                 }
 711                         }
 712                 }
 713                 else
 714                 {
 715                         LOG_ERROR("armjtagew_tap_execute, wrong result %d, expected %d", result, byte_length);
 716                         return ERROR_JTAG_QUEUE_FAILED;
 717                 }
 718
 719                 armjtagew_tap_init();
 720         }
 721
 722         return ERROR_OK;
 723 }
 724
 725 /*****************************************************************************/
 726 /* JLink USB low-level functions */
 727
 728 static struct armjtagew* armjtagew_usb_open()
 729 {
 730         usb_init();
 731
 732         const uint16_t vids[] = { USB_VID, 0 };
 733         const uint16_t pids[] = { USB_PID, 0 };
 734         struct usb_dev_handle *dev;
 735         if (jtag_usb_open(vids, pids, &dev) != ERROR_OK)
 736                 return NULL;
 737
 738         struct armjtagew *result = malloc(sizeof(struct armjtagew));
 739         result->usb_handle = dev;
 740
 741 #if 0
 742         /* usb_set_configuration required under win32 */
 743         usb_set_configuration(dev, dev->config[0].bConfigurationValue);
 744 #endif
 745         usb_claim_interface(dev, 0);
 746 #if 0
 747         /*
 748          * This makes problems under Mac OS X. And is not needed
 749          * under Windows. Hopefully this will not break a linux build
 750          */
 751         usb_set_altinterface(dev, 0);
 752 #endif
 753         return result;
 754 }
 755
 756 static void armjtagew_usb_close(struct armjtagew *armjtagew)
 757 {
 758         usb_close(armjtagew->usb_handle);
 759         free(armjtagew);
 760 }
 761
 762 /* Send a message and receive the reply. */
 763 static int armjtagew_usb_message(struct armjtagew *armjtagew, int out_length, int in_length)
 764 {
 765         int result;
 766
 767         result = armjtagew_usb_write(armjtagew, out_length);
 768         if (result == out_length)
 769         {
 770                 result = armjtagew_usb_read(armjtagew, in_length);
 771                 if (result != in_length)
 772                 {
 773                         LOG_ERROR("usb_bulk_read failed (requested=%d, result=%d)", in_length, result);
 774                         return -1;
 775                 }
 776         }
 777         else
 778         {
 779                 LOG_ERROR("usb_bulk_write failed (requested=%d, result=%d)", out_length, result);
 780                 return -1;
 781         }
 782         return 0;
 783 }
 784
 785 /* Write data from out_buffer to USB. */
 786 static int armjtagew_usb_write(struct armjtagew *armjtagew, int out_length)
 787 {
 788         int result;
 789
 790         if (out_length > ARMJTAGEW_OUT_BUFFER_SIZE)
 791         {
 792                 LOG_ERROR("armjtagew_write illegal out_length=%d (max=%d)", out_length, ARMJTAGEW_OUT_BUFFER_SIZE);
 793                 return -1;
 794         }
 795
 796         result = usb_bulk_write(armjtagew->usb_handle, ARMJTAGEW_EPT_BULK_OUT, \
 797                 (char*)usb_out_buffer, out_length, ARMJTAGEW_USB_TIMEOUT);
 798
 799         DEBUG_JTAG_IO("armjtagew_usb_write, out_length = %d, result = %d", out_length, result);
 800
 801 #ifdef _DEBUG_USB_COMMS_
 802         armjtagew_debug_buffer(usb_out_buffer, out_length);
 803 #endif
 804         return result;
 805 }
 806
 807 /* Read data from USB into in_buffer. */
 808 static int armjtagew_usb_read(struct armjtagew *armjtagew, int exp_in_length)
 809 {
 810         int result = usb_bulk_read(armjtagew->usb_handle, ARMJTAGEW_EPT_BULK_IN, \
 811                 (char*)usb_in_buffer, exp_in_length, ARMJTAGEW_USB_TIMEOUT);
 812
 813         DEBUG_JTAG_IO("armjtagew_usb_read, result = %d", result);
 814
 815 #ifdef _DEBUG_USB_COMMS_
 816         armjtagew_debug_buffer(usb_in_buffer, result);
 817 #endif
 818         return result;
 819 }
 820
 821 #ifdef _DEBUG_USB_COMMS_
 822 #define BYTES_PER_LINE  16
 823
 824 static void armjtagew_debug_buffer(uint8_t *buffer, int length)
 825 {
 826         char line[81];
 827         char s[4];
 828         int i;
 829         int j;
 830
 831         for (i = 0; i < length; i += BYTES_PER_LINE)
 832         {
 833                 snprintf(line, 5, "%04x", i);
 834                 for (j = i; j < i + BYTES_PER_LINE && j < length; j++)
 835                 {
 836                         snprintf(s, 4, " %02x", buffer[j]);
 837                         strcat(line, s);
 838                 }
 839                 LOG_DEBUG("%s", line);
 840
 841                 // Prevent GDB timeout (writing to log might take some time)
 842                 keep_alive();
 843         }
 844 }
 845 #endif