git.gag.com Git - fw/openocd/blob - src/jtag/drivers/bitbang.c

   1 /***************************************************************************
   2  *   Copyright (C) 2005 by Dominic Rath                                    *
   3  *   Dominic.Rath@gmx.de                                                   *
   4  *                                                                         *
   5  *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
   6  *   oyvind.harboe@zylin.com                                               *
   7  *                                                                         *
   8  *   This program is free software; you can redistribute it and/or modify  *
   9  *   it under the terms of the GNU General Public License as published by  *
  10  *   the Free Software Foundation; either version 2 of the License, or     *
  11  *   (at your option) any later version.                                   *
  12  *                                                                         *
  13  *   This program is distributed in the hope that it will be useful,       *
  14  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  16  *   GNU General Public License for more details.                          *
  17  *                                                                         *
  18  *   You should have received a copy of the GNU General Public License     *
  19  *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  20  ***************************************************************************/
  21
  22 /* 2014-12: Addition of the SWD protocol support is based on the initial work
  23  * by Paul Fertser and modifications by Jean-Christian de Rivaz. */
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28
  29 #include "bitbang.h"
  30 #include <jtag/interface.h>
  31 #include <jtag/commands.h>
  32
  33 /* YUK! - but this is currently a global.... */
  34 extern struct jtag_interface *jtag_interface;
  35
  36 /**
  37  * Function bitbang_stableclocks
  38  * issues a number of clock cycles while staying in a stable state.
  39  * Because the TMS value required to stay in the RESET state is a 1, whereas
  40  * the TMS value required to stay in any of the other stable states is a 0,
  41  * this function checks the current stable state to decide on the value of TMS
  42  * to use.
  43  */
  44 static void bitbang_stableclocks(int num_cycles);
  45
  46 static void bitbang_swd_write_reg(uint8_t cmd, uint32_t value, uint32_t ap_delay_clk);
  47
  48 struct bitbang_interface *bitbang_interface;
  49
  50 /* DANGER!!!! clock absolutely *MUST* be 0 in idle or reset won't work!
  51  *
  52  * Set this to 1 and str912 reset halt will fail.
  53  *
  54  * If someone can submit a patch with an explanation it will be greatly
  55  * appreciated, but as far as I can tell (ØH) DCLK is generated upon
  56  * clk = 0 in TAP_IDLE. Good luck deducing that from the ARM documentation!
  57  * The ARM documentation uses the term "DCLK is asserted while in the TAP_IDLE
  58  * state". With hardware there is no such thing as *while* in a state. There
  59  * are only edges. So clk => 0 is in fact a very subtle state transition that
  60  * happens *while* in the TAP_IDLE state. "#&¤"#¤&"#&"#&
  61  *
  62  * For "reset halt" the last thing that happens before srst is asserted
  63  * is that the breakpoint is set up. If DCLK is not wiggled one last
  64  * time before the reset, then the breakpoint is not set up and
  65  * "reset halt" will fail to halt.
  66  *
  67  */
  68 #define CLOCK_IDLE() 0
  69
  70 /* The bitbang driver leaves the TCK 0 when in idle */
  71 static void bitbang_end_state(tap_state_t state)
  72 {
  73         if (tap_is_state_stable(state))
  74                 tap_set_end_state(state);
  75         else {
  76                 LOG_ERROR("BUG: %i is not a valid end state", state);
  77                 exit(-1);
  78         }
  79 }
  80
  81 static void bitbang_state_move(int skip)
  82 {
  83         int i = 0, tms = 0;
  84         uint8_t tms_scan = tap_get_tms_path(tap_get_state(), tap_get_end_state());
  85         int tms_count = tap_get_tms_path_len(tap_get_state(), tap_get_end_state());
  86
  87         for (i = skip; i < tms_count; i++) {
  88                 tms = (tms_scan >> i) & 1;
  89                 bitbang_interface->write(0, tms, 0);
  90                 bitbang_interface->write(1, tms, 0);
  91         }
  92         bitbang_interface->write(CLOCK_IDLE(), tms, 0);
  93
  94         tap_set_state(tap_get_end_state());
  95 }
  96
  97 /**
  98  * Clock a bunch of TMS (or SWDIO) transitions, to change the JTAG
  99  * (or SWD) state machine.
 100  */
 101 static int bitbang_execute_tms(struct jtag_command *cmd)
 102 {
 103         unsigned num_bits = cmd->cmd.tms->num_bits;
 104         const uint8_t *bits = cmd->cmd.tms->bits;
 105
 106         DEBUG_JTAG_IO("TMS: %d bits", num_bits);
 107
 108         int tms = 0;
 109         for (unsigned i = 0; i < num_bits; i++) {
 110                 tms = ((bits[i/8] >> (i % 8)) & 1);
 111                 bitbang_interface->write(0, tms, 0);
 112                 bitbang_interface->write(1, tms, 0);
 113         }
 114         bitbang_interface->write(CLOCK_IDLE(), tms, 0);
 115
 116         return ERROR_OK;
 117 }
 118
 119 static void bitbang_path_move(struct pathmove_command *cmd)
 120 {
 121         int num_states = cmd->num_states;
 122         int state_count;
 123         int tms = 0;
 124
 125         state_count = 0;
 126         while (num_states) {
 127                 if (tap_state_transition(tap_get_state(), false) == cmd->path[state_count])
 128                         tms = 0;
 129                 else if (tap_state_transition(tap_get_state(), true) == cmd->path[state_count])
 130                         tms = 1;
 131                 else {
 132                         LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition",
 133                                 tap_state_name(tap_get_state()),
 134                                 tap_state_name(cmd->path[state_count]));
 135                         exit(-1);
 136                 }
 137
 138                 bitbang_interface->write(0, tms, 0);
 139                 bitbang_interface->write(1, tms, 0);
 140
 141                 tap_set_state(cmd->path[state_count]);
 142                 state_count++;
 143                 num_states--;
 144         }
 145
 146         bitbang_interface->write(CLOCK_IDLE(), tms, 0);
 147
 148         tap_set_end_state(tap_get_state());
 149 }
 150
 151 static void bitbang_runtest(int num_cycles)
 152 {
 153         int i;
 154
 155         tap_state_t saved_end_state = tap_get_end_state();
 156
 157         /* only do a state_move when we're not already in IDLE */
 158         if (tap_get_state() != TAP_IDLE) {
 159                 bitbang_end_state(TAP_IDLE);
 160                 bitbang_state_move(0);
 161         }
 162
 163         /* execute num_cycles */
 164         for (i = 0; i < num_cycles; i++) {
 165                 bitbang_interface->write(0, 0, 0);
 166                 bitbang_interface->write(1, 0, 0);
 167         }
 168         bitbang_interface->write(CLOCK_IDLE(), 0, 0);
 169
 170         /* finish in end_state */
 171         bitbang_end_state(saved_end_state);
 172         if (tap_get_state() != tap_get_end_state())
 173                 bitbang_state_move(0);
 174 }
 175
 176 static void bitbang_stableclocks(int num_cycles)
 177 {
 178         int tms = (tap_get_state() == TAP_RESET ? 1 : 0);
 179         int i;
 180
 181         /* send num_cycles clocks onto the cable */
 182         for (i = 0; i < num_cycles; i++) {
 183                 bitbang_interface->write(1, tms, 0);
 184                 bitbang_interface->write(0, tms, 0);
 185         }
 186 }
 187
 188 static void bitbang_scan(bool ir_scan, enum scan_type type, uint8_t *buffer, int scan_size)
 189 {
 190         tap_state_t saved_end_state = tap_get_end_state();
 191         int bit_cnt;
 192
 193         if (!((!ir_scan &&
 194                         (tap_get_state() == TAP_DRSHIFT)) ||
 195                         (ir_scan && (tap_get_state() == TAP_IRSHIFT)))) {
 196                 if (ir_scan)
 197                         bitbang_end_state(TAP_IRSHIFT);
 198                 else
 199                         bitbang_end_state(TAP_DRSHIFT);
 200
 201                 bitbang_state_move(0);
 202                 bitbang_end_state(saved_end_state);
 203         }
 204
 205         for (bit_cnt = 0; bit_cnt < scan_size; bit_cnt++) {
 206                 int val = 0;
 207                 int tms = (bit_cnt == scan_size-1) ? 1 : 0;
 208                 int tdi;
 209                 int bytec = bit_cnt/8;
 210                 int bcval = 1 << (bit_cnt % 8);
 211
 212                 /* if we're just reading the scan, but don't care about the output
 213                  * default to outputting 'low', this also makes valgrind traces more readable,
 214                  * as it removes the dependency on an uninitialised value
 215                  */
 216                 tdi = 0;
 217                 if ((type != SCAN_IN) && (buffer[bytec] & bcval))
 218                         tdi = 1;
 219
 220                 bitbang_interface->write(0, tms, tdi);
 221
 222                 if (type != SCAN_OUT)
 223                         val = bitbang_interface->read();
 224
 225                 bitbang_interface->write(1, tms, tdi);
 226
 227                 if (type != SCAN_OUT) {
 228                         if (val)
 229                                 buffer[bytec] |= bcval;
 230                         else
 231                                 buffer[bytec] &= ~bcval;
 232                 }
 233         }
 234
 235         if (tap_get_state() != tap_get_end_state()) {
 236                 /* we *KNOW* the above loop transitioned out of
 237                  * the shift state, so we skip the first state
 238                  * and move directly to the end state.
 239                  */
 240                 bitbang_state_move(1);
 241         }
 242 }
 243
 244 int bitbang_execute_queue(void)
 245 {
 246         struct jtag_command *cmd = jtag_command_queue;  /* currently processed command */
 247         int scan_size;
 248         enum scan_type type;
 249         uint8_t *buffer;
 250         int retval;
 251
 252         if (!bitbang_interface) {
 253                 LOG_ERROR("BUG: Bitbang interface called, but not yet initialized");
 254                 exit(-1);
 255         }
 256
 257         /* return ERROR_OK, unless a jtag_read_buffer returns a failed check
 258          * that wasn't handled by a caller-provided error handler
 259          */
 260         retval = ERROR_OK;
 261
 262         if (bitbang_interface->blink)
 263                 bitbang_interface->blink(1);
 264
 265         while (cmd) {
 266                 switch (cmd->type) {
 267                         case JTAG_RESET:
 268 #ifdef _DEBUG_JTAG_IO_
 269                                 LOG_DEBUG("reset trst: %i srst %i",
 270                                 cmd->cmd.reset->trst,
 271                                 cmd->cmd.reset->srst);
 272 #endif
 273                                 if ((cmd->cmd.reset->trst == 1) ||
 274                                                 (cmd->cmd.reset->srst && (jtag_get_reset_config() & RESET_SRST_PULLS_TRST)))
 275                                         tap_set_state(TAP_RESET);
 276                                 bitbang_interface->reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
 277                                 break;
 278                         case JTAG_RUNTEST:
 279 #ifdef _DEBUG_JTAG_IO_
 280                                 LOG_DEBUG("runtest %i cycles, end in %s",
 281                                                 cmd->cmd.runtest->num_cycles,
 282                                                 tap_state_name(cmd->cmd.runtest->end_state));
 283 #endif
 284                                 bitbang_end_state(cmd->cmd.runtest->end_state);
 285                                 bitbang_runtest(cmd->cmd.runtest->num_cycles);
 286                                 break;
 287
 288                         case JTAG_STABLECLOCKS:
 289                                 /* this is only allowed while in a stable state.  A check for a stable
 290                                  * state was done in jtag_add_clocks()
 291                                  */
 292                                 bitbang_stableclocks(cmd->cmd.stableclocks->num_cycles);
 293                                 break;
 294
 295                         case JTAG_TLR_RESET:
 296 #ifdef _DEBUG_JTAG_IO_
 297                                 LOG_DEBUG("statemove end in %s",
 298                                                 tap_state_name(cmd->cmd.statemove->end_state));
 299 #endif
 300                                 bitbang_end_state(cmd->cmd.statemove->end_state);
 301                                 bitbang_state_move(0);
 302                                 break;
 303                         case JTAG_PATHMOVE:
 304 #ifdef _DEBUG_JTAG_IO_
 305                                 LOG_DEBUG("pathmove: %i states, end in %s",
 306                                                 cmd->cmd.pathmove->num_states,
 307                                                 tap_state_name(cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]));
 308 #endif
 309                                 bitbang_path_move(cmd->cmd.pathmove);
 310                                 break;
 311                         case JTAG_SCAN:
 312 #ifdef _DEBUG_JTAG_IO_
 313                                 LOG_DEBUG("%s scan end in %s",
 314                                                 (cmd->cmd.scan->ir_scan) ? "IR" : "DR",
 315                                         tap_state_name(cmd->cmd.scan->end_state));
 316 #endif
 317                                 bitbang_end_state(cmd->cmd.scan->end_state);
 318                                 scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
 319                                 type = jtag_scan_type(cmd->cmd.scan);
 320                                 bitbang_scan(cmd->cmd.scan->ir_scan, type, buffer, scan_size);
 321                                 if (jtag_read_buffer(buffer, cmd->cmd.scan) != ERROR_OK)
 322                                         retval = ERROR_JTAG_QUEUE_FAILED;
 323                                 if (buffer)
 324                                         free(buffer);
 325                                 break;
 326                         case JTAG_SLEEP:
 327 #ifdef _DEBUG_JTAG_IO_
 328                                 LOG_DEBUG("sleep %" PRIi32, cmd->cmd.sleep->us);
 329 #endif
 330                                 jtag_sleep(cmd->cmd.sleep->us);
 331                                 break;
 332                         case JTAG_TMS:
 333                                 retval = bitbang_execute_tms(cmd);
 334                                 break;
 335                         default:
 336                                 LOG_ERROR("BUG: unknown JTAG command type encountered");
 337                                 exit(-1);
 338                 }
 339                 cmd = cmd->next;
 340         }
 341         if (bitbang_interface->blink)
 342                 bitbang_interface->blink(0);
 343
 344         return retval;
 345 }
 346
 347
 348 bool swd_mode;
 349 static int queued_retval;
 350
 351 static int bitbang_swd_init(void)
 352 {
 353         LOG_DEBUG("bitbang_swd_init");
 354         swd_mode = true;
 355         return ERROR_OK;
 356 }
 357
 358 static void bitbang_exchange(bool rnw, uint8_t buf[], unsigned int offset, unsigned int bit_cnt)
 359 {
 360         LOG_DEBUG("bitbang_exchange");
 361         int tdi;
 362
 363         for (unsigned int i = offset; i < bit_cnt + offset; i++) {
 364                 int bytec = i/8;
 365                 int bcval = 1 << (i % 8);
 366                 tdi = !rnw && (buf[bytec] & bcval);
 367
 368                 bitbang_interface->write(0, 0, tdi);
 369
 370                 if (rnw && buf) {
 371                         if (bitbang_interface->swdio_read())
 372                                 buf[bytec] |= bcval;
 373                         else
 374                                 buf[bytec] &= ~bcval;
 375                 }
 376
 377                 bitbang_interface->write(1, 0, tdi);
 378         }
 379 }
 380
 381 int bitbang_swd_switch_seq(enum swd_special_seq seq)
 382 {
 383         LOG_DEBUG("bitbang_swd_switch_seq");
 384
 385         switch (seq) {
 386         case LINE_RESET:
 387                 LOG_DEBUG("SWD line reset");
 388                 bitbang_exchange(false, (uint8_t *)swd_seq_line_reset, 0, swd_seq_line_reset_len);
 389                 break;
 390         case JTAG_TO_SWD:
 391                 LOG_DEBUG("JTAG-to-SWD");
 392                 bitbang_exchange(false, (uint8_t *)swd_seq_jtag_to_swd, 0, swd_seq_jtag_to_swd_len);
 393                 break;
 394         case SWD_TO_JTAG:
 395                 LOG_DEBUG("SWD-to-JTAG");
 396                 bitbang_exchange(false, (uint8_t *)swd_seq_swd_to_jtag, 0, swd_seq_swd_to_jtag_len);
 397                 break;
 398         default:
 399                 LOG_ERROR("Sequence %d not supported", seq);
 400                 return ERROR_FAIL;
 401         }
 402
 403         return ERROR_OK;
 404 }
 405
 406 void bitbang_switch_to_swd(void)
 407 {
 408         LOG_DEBUG("bitbang_switch_to_swd");
 409         bitbang_exchange(false, (uint8_t *)swd_seq_jtag_to_swd, 0, swd_seq_jtag_to_swd_len);
 410 }
 411
 412 static void swd_clear_sticky_errors(void)
 413 {
 414         bitbang_swd_write_reg(swd_cmd(false,  false, DP_ABORT),
 415                 STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR, 0);
 416 }
 417
 418 static void bitbang_swd_read_reg(uint8_t cmd, uint32_t *value, uint32_t ap_delay_clk)
 419 {
 420         LOG_DEBUG("bitbang_swd_read_reg");
 421         assert(cmd & SWD_CMD_RnW);
 422
 423         if (queued_retval != ERROR_OK) {
 424                 LOG_DEBUG("Skip bitbang_swd_read_reg because queued_retval=%d", queued_retval);
 425                 return;
 426         }
 427
 428         for (;;) {
 429                 uint8_t trn_ack_data_parity_trn[DIV_ROUND_UP(4 + 3 + 32 + 1 + 4, 8)];
 430
 431                 cmd |= SWD_CMD_START | (1 << 7);
 432                 bitbang_exchange(false, &cmd, 0, 8);
 433
 434                 bitbang_interface->swdio_drive(false);
 435                 bitbang_exchange(true, trn_ack_data_parity_trn, 0, 1 + 3 + 32 + 1 + 1);
 436                 bitbang_interface->swdio_drive(true);
 437
 438                 int ack = buf_get_u32(trn_ack_data_parity_trn, 1, 3);
 439                 uint32_t data = buf_get_u32(trn_ack_data_parity_trn, 1 + 3, 32);
 440                 int parity = buf_get_u32(trn_ack_data_parity_trn, 1 + 3 + 32, 1);
 441
 442                 LOG_DEBUG("%s %s %s reg %X = %08"PRIx32,
 443                           ack == SWD_ACK_OK ? "OK" : ack == SWD_ACK_WAIT ? "WAIT" : ack == SWD_ACK_FAULT ? "FAULT" : "JUNK",
 444                           cmd & SWD_CMD_APnDP ? "AP" : "DP",
 445                           cmd & SWD_CMD_RnW ? "read" : "write",
 446                           (cmd & SWD_CMD_A32) >> 1,
 447                           data);
 448
 449                 switch (ack) {
 450                  case SWD_ACK_OK:
 451                         if (parity != parity_u32(data)) {
 452                                 LOG_DEBUG("Wrong parity detected");
 453                                 queued_retval = ERROR_FAIL;
 454                                 return;
 455                         }
 456                         if (value)
 457                                 *value = data;
 458                         if (cmd & SWD_CMD_APnDP)
 459                                 bitbang_exchange(true, NULL, 0, ap_delay_clk);
 460                         return;
 461                  case SWD_ACK_WAIT:
 462                         LOG_DEBUG("SWD_ACK_WAIT");
 463                         swd_clear_sticky_errors();
 464                         break;
 465                  case SWD_ACK_FAULT:
 466                         LOG_DEBUG("SWD_ACK_FAULT");
 467                         queued_retval = ack;
 468                         return;
 469                  default:
 470                         LOG_DEBUG("No valid acknowledge: ack=%d", ack);
 471                         queued_retval = ack;
 472                         return;
 473                 }
 474         }
 475 }
 476
 477 static void bitbang_swd_write_reg(uint8_t cmd, uint32_t value, uint32_t ap_delay_clk)
 478 {
 479         LOG_DEBUG("bitbang_swd_write_reg");
 480         assert(!(cmd & SWD_CMD_RnW));
 481
 482         if (queued_retval != ERROR_OK) {
 483                 LOG_DEBUG("Skip bitbang_swd_write_reg because queued_retval=%d", queued_retval);
 484                 return;
 485         }
 486
 487         for (;;) {
 488                 uint8_t trn_ack_data_parity_trn[DIV_ROUND_UP(4 + 3 + 32 + 1 + 4, 8)];
 489                 buf_set_u32(trn_ack_data_parity_trn, 1 + 3 + 1, 32, value);
 490                 buf_set_u32(trn_ack_data_parity_trn, 1 + 3 + 1 + 32, 1, parity_u32(value));
 491
 492                 cmd |= SWD_CMD_START | (1 << 7);
 493                 bitbang_exchange(false, &cmd, 0, 8);
 494
 495                 bitbang_interface->swdio_drive(false);
 496                 bitbang_exchange(true, trn_ack_data_parity_trn, 0, 1 + 3 + 1);
 497                 bitbang_interface->swdio_drive(true);
 498                 bitbang_exchange(false, trn_ack_data_parity_trn, 1 + 3 + 1, 32 + 1);
 499
 500                 int ack = buf_get_u32(trn_ack_data_parity_trn, 1, 3);
 501                 LOG_DEBUG("%s %s %s reg %X = %08"PRIx32,
 502                           ack == SWD_ACK_OK ? "OK" : ack == SWD_ACK_WAIT ? "WAIT" : ack == SWD_ACK_FAULT ? "FAULT" : "JUNK",
 503                           cmd & SWD_CMD_APnDP ? "AP" : "DP",
 504                           cmd & SWD_CMD_RnW ? "read" : "write",
 505                           (cmd & SWD_CMD_A32) >> 1,
 506                           buf_get_u32(trn_ack_data_parity_trn, 1 + 3 + 1, 32));
 507
 508                 switch (ack) {
 509                  case SWD_ACK_OK:
 510                         if (cmd & SWD_CMD_APnDP)
 511                                 bitbang_exchange(true, NULL, 0, ap_delay_clk);
 512                         return;
 513                  case SWD_ACK_WAIT:
 514                         LOG_DEBUG("SWD_ACK_WAIT");
 515                         swd_clear_sticky_errors();
 516                         break;
 517                  case SWD_ACK_FAULT:
 518                         LOG_DEBUG("SWD_ACK_FAULT");
 519                         queued_retval = ack;
 520                         return;
 521                  default:
 522                         LOG_DEBUG("No valid acknowledge: ack=%d", ack);
 523                         queued_retval = ack;
 524                         return;
 525                 }
 526         }
 527 }
 528
 529 static int bitbang_swd_run_queue(void)
 530 {
 531         LOG_DEBUG("bitbang_swd_run_queue");
 532         /* A transaction must be followed by another transaction or at least 8 idle cycles to
 533          * ensure that data is clocked through the AP. */
 534         bitbang_exchange(true, NULL, 0, 8);
 535
 536         int retval = queued_retval;
 537         queued_retval = ERROR_OK;
 538         LOG_DEBUG("SWD queue return value: %02x", retval);
 539         return retval;
 540 }
 541
 542 const struct swd_driver bitbang_swd = {
 543         .init = bitbang_swd_init,
 544         .switch_seq = bitbang_swd_switch_seq,
 545         .read_reg = bitbang_swd_read_reg,
 546         .write_reg = bitbang_swd_write_reg,
 547         .run = bitbang_swd_run_queue,
 548 };