src/jtag/drivers/sysfsgpio.c

   1 /***************************************************************************
   2  *   Copyright (C) 2012 by Creative Product Design, marc @ cpdesign.com.au *
   3  *                                                                         *
   4  *   This program is free software; you can redistribute it and/or modify  *
   5  *   it under the terms of the GNU General Public License as published by  *
   6  *   the Free Software Foundation; either version 2 of the License, or     *
   7  *   (at your option) any later version.                                   *
   8  *                                                                         *
   9  *   This program is distributed in the hope that it will be useful,       *
  10  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  12  *   GNU General Public License for more details.                          *
  13  *                                                                         *
  14  *   You should have received a copy of the GNU General Public License     *
  15  *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  16  ***************************************************************************/
  17
  18 /* 2014-12: Addition of the SWD protocol support is based on the initial work
  19  * on bcm2835gpio.c by Paul Fertser and modifications by Jean-Christian de Rivaz. */
  20
  21 /**
  22  * @file
  23  * This driver implements a bitbang jtag interface using gpio lines via
  24  * sysfs.
  25  * The aim of this driver implementation is use system GPIOs but avoid the
  26  * need for a additional kernel driver.
  27  * (Note memory mapped IO is another option, however it doesn't mix well with
  28  * the kernel gpiolib driver - which makes sense I guess.)
  29  *
  30  * A gpio is required for tck, tms, tdi and tdo. One or both of srst and trst
  31  * must be also be specified. The required jtag gpios are specified via the
  32  * sysfsgpio_jtag_nums command or the relevant sysfsgpio_XXX_num commang.
  33  * The srst and trst gpios are set via the sysfsgpio_srst_num and
  34  * sysfsgpio_trst_num respectively. GPIO numbering follows the kernel
  35  * convention of starting from 0.
  36  *
  37  * The gpios should not be in use by another entity, and must not be requested
  38  * by a kernel driver without also being exported by it (otherwise they can't
  39  * be exported by sysfs).
  40  *
  41  * The sysfs gpio interface can only manipulate one gpio at a time, so the
  42  * bitbang write handler remembers the last state for tck, tms, tdi to avoid
  43  * superfluous writes.
  44  * For speed the sysfs "value" entry is opened at init and held open.
  45  * This results in considerable gains over open-write-close (45s vs 900s)
  46  *
  47  * Further work could address:
  48  *  -srst and trst open drain/ push pull
  49  *  -configurable active high/low for srst & trst
  50  */
  51 #ifdef HAVE_CONFIG_H
  52 #include "config.h"
  53 #endif
  54
  55 #include <helper/time_support.h>
  56 #include <jtag/interface.h>
  57 #include "bitbang.h"
  58
  59 /*
  60  * Helper func to determine if gpio number valid
  61  *
  62  * Assume here that there will be less than 10000 gpios on a system
  63  */
  64 static bool is_gpio_valid(int gpio)
  65 {
  66         return gpio >= 0 && gpio < 10000;
  67 }
  68
  69 /*
  70  * Helper func to open, write to and close a file
  71  * name and valstr must be null terminated.
  72  *
  73  * Returns negative on failure.
  74  */
  75 static int open_write_close(const char *name, const char *valstr)
  76 {
  77         int ret;
  78         int fd = open(name, O_WRONLY);
  79         if (fd < 0)
  80                 return fd;
  81
  82         ret = write(fd, valstr, strlen(valstr));
  83         close(fd);
  84
  85         return ret;
  86 }
  87
  88 /*
  89  * Helper func to unexport gpio from sysfs
  90  */
  91 static void unexport_sysfs_gpio(int gpio)
  92 {
  93         char gpiostr[5];
  94
  95         if (!is_gpio_valid(gpio))
  96                 return;
  97
  98         snprintf(gpiostr, sizeof(gpiostr), "%d", gpio);
  99         if (open_write_close("/sys/class/gpio/unexport", gpiostr) < 0)
 100                 LOG_ERROR("Couldn't unexport gpio %d", gpio);
 101 }
 102
 103 /*
 104  * Exports and sets up direction for gpio.
 105  * If the gpio is an output, it is initialized according to init_high,
 106  * otherwise it is ignored.
 107  *
 108  * If the gpio is already exported we just show a warning and continue; if
 109  * openocd happened to crash (or was killed by user) then the gpios will not
 110  * have been cleaned up.
 111  */
 112 static int setup_sysfs_gpio(int gpio, int is_output, int init_high)
 113 {
 114         struct timeval timeout, now;
 115         char buf[40];
 116         char gpiostr[5];
 117         int ret;
 118
 119         if (!is_gpio_valid(gpio))
 120                 return ERROR_OK;
 121
 122         snprintf(gpiostr, sizeof(gpiostr), "%d", gpio);
 123         ret = open_write_close("/sys/class/gpio/export", gpiostr);
 124         if (ret < 0) {
 125                 if (errno == EBUSY) {
 126                         LOG_WARNING("gpio %d is already exported", gpio);
 127                 } else {
 128                         LOG_ERROR("Couldn't export gpio %d", gpio);
 129                         perror("sysfsgpio: ");
 130                         return ERROR_FAIL;
 131                 }
 132         }
 133
 134         gettimeofday(&timeout, NULL);
 135         timeval_add_time(&timeout, 0, 500000);
 136
 137         snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/direction", gpio);
 138         for (;;) {
 139                 ret = open_write_close(buf, is_output ? (init_high ? "high" : "low") : "in");
 140                 if (ret >= 0 || errno != EACCES)
 141                         break;
 142                 gettimeofday(&now, NULL);
 143                 if (timeval_compare(&now, &timeout) >= 0)
 144                         break;
 145                 jtag_sleep(10000);
 146         }
 147         if (ret < 0) {
 148                 LOG_ERROR("Couldn't set direction for gpio %d", gpio);
 149                 perror("sysfsgpio: ");
 150                 unexport_sysfs_gpio(gpio);
 151                 return ERROR_FAIL;
 152         }
 153
 154         snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/value", gpio);
 155         for (;;) {
 156                 ret = open(buf, O_RDWR | O_NONBLOCK | O_SYNC);
 157                 if (ret >= 0 || errno != EACCES)
 158                         break;
 159                 gettimeofday(&now, NULL);
 160                 if (timeval_compare(&now, &timeout) >= 0)
 161                         break;
 162                 jtag_sleep(10000);
 163         }
 164         if (ret < 0) {
 165                 LOG_ERROR("Couldn't open value for gpio %d", gpio);
 166                 perror("sysfsgpio: ");
 167                 unexport_sysfs_gpio(gpio);
 168         }
 169
 170         return ret;
 171 }
 172
 173 /* gpio numbers for each gpio. Negative values are invalid */
 174 static int tck_gpio = -1;
 175 static int tms_gpio = -1;
 176 static int tdi_gpio = -1;
 177 static int tdo_gpio = -1;
 178 static int trst_gpio = -1;
 179 static int srst_gpio = -1;
 180 static int swclk_gpio = -1;
 181 static int swdio_gpio = -1;
 182
 183 /*
 184  * file descriptors for /sys/class/gpio/gpioXX/value
 185  * Set up during init.
 186  */
 187 static int tck_fd = -1;
 188 static int tms_fd = -1;
 189 static int tdi_fd = -1;
 190 static int tdo_fd = -1;
 191 static int trst_fd = -1;
 192 static int srst_fd = -1;
 193 static int swclk_fd = -1;
 194 static int swdio_fd = -1;
 195
 196 static int last_swclk;
 197 static int last_swdio;
 198 static bool last_stored;
 199 static bool swdio_input;
 200
 201 static void sysfsgpio_swdio_drive(bool is_output)
 202 {
 203         char buf[40];
 204         int ret;
 205
 206         snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/direction", swdio_gpio);
 207         ret = open_write_close(buf, is_output ? "high" : "in");
 208         if (ret < 0) {
 209                 LOG_ERROR("Couldn't set direction for gpio %d", swdio_gpio);
 210                 perror("sysfsgpio: ");
 211         }
 212
 213         last_stored = false;
 214         swdio_input = !is_output;
 215 }
 216
 217 static int sysfsgpio_swdio_read(void)
 218 {
 219         char buf[1];
 220
 221         /* important to seek to signal sysfs of new read */
 222         lseek(swdio_fd, 0, SEEK_SET);
 223         int ret = read(swdio_fd, &buf, sizeof(buf));
 224
 225         if (ret < 0) {
 226                 LOG_WARNING("reading swdio failed");
 227                 return 0;
 228         }
 229
 230         return buf[0] != '0';
 231 }
 232
 233 static int sysfsgpio_swd_write(int swclk, int swdio)
 234 {
 235         const char one[] = "1";
 236         const char zero[] = "0";
 237
 238         size_t bytes_written;
 239
 240         if (!swdio_input) {
 241                 if (!last_stored || (swdio != last_swdio)) {
 242                         bytes_written = write(swdio_fd, swdio ? &one : &zero, 1);
 243                         if (bytes_written != 1)
 244                                 LOG_WARNING("writing swdio failed");
 245                 }
 246         }
 247
 248         /* write swclk last */
 249         if (!last_stored || (swclk != last_swclk)) {
 250                 bytes_written = write(swclk_fd, swclk ? &one : &zero, 1);
 251                 if (bytes_written != 1)
 252                         LOG_WARNING("writing swclk failed");
 253         }
 254
 255         last_swdio = swdio;
 256         last_swclk = swclk;
 257         last_stored = true;
 258
 259         return ERROR_OK;
 260 }
 261
 262 /*
 263  * Bitbang interface read of TDO
 264  *
 265  * The sysfs value will read back either '0' or '1'. The trick here is to call
 266  * lseek to bypass buffering in the sysfs kernel driver.
 267  */
 268 static bb_value_t sysfsgpio_read(void)
 269 {
 270         char buf[1];
 271
 272         /* important to seek to signal sysfs of new read */
 273         lseek(tdo_fd, 0, SEEK_SET);
 274         int ret = read(tdo_fd, &buf, sizeof(buf));
 275
 276         if (ret < 0) {
 277                 LOG_WARNING("reading tdo failed");
 278                 return 0;
 279         }
 280
 281         return buf[0] == '0' ? BB_LOW : BB_HIGH;
 282 }
 283
 284 /*
 285  * Bitbang interface write of TCK, TMS, TDI
 286  *
 287  * Seeing as this is the only function where the outputs are changed,
 288  * we can cache the old value to avoid needlessly writing it.
 289  */
 290 static int sysfsgpio_write(int tck, int tms, int tdi)
 291 {
 292         const char one[] = "1";
 293         const char zero[] = "0";
 294
 295         static int last_tck;
 296         static int last_tms;
 297         static int last_tdi;
 298
 299         static int first_time;
 300         size_t bytes_written;
 301
 302         if (!first_time) {
 303                 last_tck = !tck;
 304                 last_tms = !tms;
 305                 last_tdi = !tdi;
 306                 first_time = 1;
 307         }
 308
 309         if (tdi != last_tdi) {
 310                 bytes_written = write(tdi_fd, tdi ? &one : &zero, 1);
 311                 if (bytes_written != 1)
 312                         LOG_WARNING("writing tdi failed");
 313         }
 314
 315         if (tms != last_tms) {
 316                 bytes_written = write(tms_fd, tms ? &one : &zero, 1);
 317                 if (bytes_written != 1)
 318                         LOG_WARNING("writing tms failed");
 319         }
 320
 321         /* write clk last */
 322         if (tck != last_tck) {
 323                 bytes_written = write(tck_fd, tck ? &one : &zero, 1);
 324                 if (bytes_written != 1)
 325                         LOG_WARNING("writing tck failed");
 326         }
 327
 328         last_tdi = tdi;
 329         last_tms = tms;
 330         last_tck = tck;
 331
 332         return ERROR_OK;
 333 }
 334
 335 /*
 336  * Bitbang interface to manipulate reset lines SRST and TRST
 337  *
 338  * (1) assert or (0) deassert reset lines
 339  */
 340 static int sysfsgpio_reset(int trst, int srst)
 341 {
 342         LOG_DEBUG("sysfsgpio_reset");
 343         const char one[] = "1";
 344         const char zero[] = "0";
 345         size_t bytes_written;
 346
 347         /* assume active low */
 348         if (srst_fd >= 0) {
 349                 bytes_written = write(srst_fd, srst ? &zero : &one, 1);
 350                 if (bytes_written != 1)
 351                         LOG_WARNING("writing srst failed");
 352         }
 353
 354         /* assume active low */
 355         if (trst_fd >= 0) {
 356                 bytes_written = write(trst_fd, trst ? &zero : &one, 1);
 357                 if (bytes_written != 1)
 358                         LOG_WARNING("writing trst failed");
 359         }
 360
 361         return ERROR_OK;
 362 }
 363
 364 COMMAND_HANDLER(sysfsgpio_handle_jtag_gpionums)
 365 {
 366         if (CMD_ARGC == 4) {
 367                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], tck_gpio);
 368                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[1], tms_gpio);
 369                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[2], tdi_gpio);
 370                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[3], tdo_gpio);
 371         } else if (CMD_ARGC != 0) {
 372                 return ERROR_COMMAND_SYNTAX_ERROR;
 373         }
 374
 375         command_print(CMD,
 376                         "SysfsGPIO nums: tck = %d, tms = %d, tdi = %d, tdo = %d",
 377                         tck_gpio, tms_gpio, tdi_gpio, tdo_gpio);
 378
 379         return ERROR_OK;
 380 }
 381
 382 COMMAND_HANDLER(sysfsgpio_handle_jtag_gpionum_tck)
 383 {
 384         if (CMD_ARGC == 1)
 385                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], tck_gpio);
 386
 387         command_print(CMD, "SysfsGPIO num: tck = %d", tck_gpio);
 388         return ERROR_OK;
 389 }
 390
 391 COMMAND_HANDLER(sysfsgpio_handle_jtag_gpionum_tms)
 392 {
 393         if (CMD_ARGC == 1)
 394                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], tms_gpio);
 395
 396         command_print(CMD, "SysfsGPIO num: tms = %d", tms_gpio);
 397         return ERROR_OK;
 398 }
 399
 400 COMMAND_HANDLER(sysfsgpio_handle_jtag_gpionum_tdo)
 401 {
 402         if (CMD_ARGC == 1)
 403                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], tdo_gpio);
 404
 405         command_print(CMD, "SysfsGPIO num: tdo = %d", tdo_gpio);
 406         return ERROR_OK;
 407 }
 408
 409 COMMAND_HANDLER(sysfsgpio_handle_jtag_gpionum_tdi)
 410 {
 411         if (CMD_ARGC == 1)
 412                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], tdi_gpio);
 413
 414         command_print(CMD, "SysfsGPIO num: tdi = %d", tdi_gpio);
 415         return ERROR_OK;
 416 }
 417
 418 COMMAND_HANDLER(sysfsgpio_handle_jtag_gpionum_srst)
 419 {
 420         if (CMD_ARGC == 1)
 421                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], srst_gpio);
 422
 423         command_print(CMD, "SysfsGPIO num: srst = %d", srst_gpio);
 424         return ERROR_OK;
 425 }
 426
 427 COMMAND_HANDLER(sysfsgpio_handle_jtag_gpionum_trst)
 428 {
 429         if (CMD_ARGC == 1)
 430                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], trst_gpio);
 431
 432         command_print(CMD, "SysfsGPIO num: trst = %d", trst_gpio);
 433         return ERROR_OK;
 434 }
 435
 436 COMMAND_HANDLER(sysfsgpio_handle_swd_gpionums)
 437 {
 438         if (CMD_ARGC == 2) {
 439                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swclk_gpio);
 440                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[1], swdio_gpio);
 441         } else if (CMD_ARGC != 0) {
 442                 return ERROR_COMMAND_SYNTAX_ERROR;
 443         }
 444
 445         command_print(CMD,
 446                         "SysfsGPIO nums: swclk = %d, swdio = %d",
 447                         swclk_gpio, swdio_gpio);
 448
 449         return ERROR_OK;
 450 }
 451
 452 COMMAND_HANDLER(sysfsgpio_handle_swd_gpionum_swclk)
 453 {
 454         if (CMD_ARGC == 1)
 455                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swclk_gpio);
 456
 457         command_print(CMD, "SysfsGPIO num: swclk = %d", swclk_gpio);
 458         return ERROR_OK;
 459 }
 460
 461 COMMAND_HANDLER(sysfsgpio_handle_swd_gpionum_swdio)
 462 {
 463         if (CMD_ARGC == 1)
 464                 COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swdio_gpio);
 465
 466         command_print(CMD, "SysfsGPIO num: swdio = %d", swdio_gpio);
 467         return ERROR_OK;
 468 }
 469
 470 static const struct command_registration sysfsgpio_command_handlers[] = {
 471         {
 472                 .name = "sysfsgpio_jtag_nums",
 473                 .handler = &sysfsgpio_handle_jtag_gpionums,
 474                 .mode = COMMAND_CONFIG,
 475                 .help = "gpio numbers for tck, tms, tdi, tdo. (in that order)",
 476                 .usage = "[tck tms tdi tdo]",
 477         },
 478         {
 479                 .name = "sysfsgpio_tck_num",
 480                 .handler = &sysfsgpio_handle_jtag_gpionum_tck,
 481                 .mode = COMMAND_CONFIG,
 482                 .help = "gpio number for tck.",
 483                 .usage = "[tck]",
 484         },
 485         {
 486                 .name = "sysfsgpio_tms_num",
 487                 .handler = &sysfsgpio_handle_jtag_gpionum_tms,
 488                 .mode = COMMAND_CONFIG,
 489                 .help = "gpio number for tms.",
 490                 .usage = "[tms]",
 491         },
 492         {
 493                 .name = "sysfsgpio_tdo_num",
 494                 .handler = &sysfsgpio_handle_jtag_gpionum_tdo,
 495                 .mode = COMMAND_CONFIG,
 496                 .help = "gpio number for tdo.",
 497                 .usage = "[tdo]",
 498         },
 499         {
 500                 .name = "sysfsgpio_tdi_num",
 501                 .handler = &sysfsgpio_handle_jtag_gpionum_tdi,
 502                 .mode = COMMAND_CONFIG,
 503                 .help = "gpio number for tdi.",
 504                 .usage = "[tdi]",
 505         },
 506         {
 507                 .name = "sysfsgpio_srst_num",
 508                 .handler = &sysfsgpio_handle_jtag_gpionum_srst,
 509                 .mode = COMMAND_CONFIG,
 510                 .help = "gpio number for srst.",
 511                 .usage = "[srst]",
 512         },
 513         {
 514                 .name = "sysfsgpio_trst_num",
 515                 .handler = &sysfsgpio_handle_jtag_gpionum_trst,
 516                 .mode = COMMAND_CONFIG,
 517                 .help = "gpio number for trst.",
 518                 .usage = "[trst]",
 519         },
 520         {
 521                 .name = "sysfsgpio_swd_nums",
 522                 .handler = &sysfsgpio_handle_swd_gpionums,
 523                 .mode = COMMAND_CONFIG,
 524                 .help = "gpio numbers for swclk, swdio. (in that order)",
 525                 .usage = "[swclk swdio]",
 526         },
 527         {
 528                 .name = "sysfsgpio_swclk_num",
 529                 .handler = &sysfsgpio_handle_swd_gpionum_swclk,
 530                 .mode = COMMAND_CONFIG,
 531                 .help = "gpio number for swclk.",
 532                 .usage = "[swclk]",
 533         },
 534         {
 535                 .name = "sysfsgpio_swdio_num",
 536                 .handler = &sysfsgpio_handle_swd_gpionum_swdio,
 537                 .mode = COMMAND_CONFIG,
 538                 .help = "gpio number for swdio.",
 539                 .usage = "[swdio]",
 540         },
 541         COMMAND_REGISTRATION_DONE
 542 };
 543
 544 static int sysfsgpio_init(void);
 545 static int sysfsgpio_quit(void);
 546
 547 static const char * const sysfsgpio_transports[] = { "jtag", "swd", NULL };
 548
 549 static struct jtag_interface sysfsgpio_interface = {
 550         .supported = DEBUG_CAP_TMS_SEQ,
 551         .execute_queue = bitbang_execute_queue,
 552 };
 553
 554 struct adapter_driver sysfsgpio_adapter_driver = {
 555         .name = "sysfsgpio",
 556         .transports = sysfsgpio_transports,
 557         .commands = sysfsgpio_command_handlers,
 558
 559         .init = sysfsgpio_init,
 560         .quit = sysfsgpio_quit,
 561         .reset = sysfsgpio_reset,
 562
 563         .jtag_ops = &sysfsgpio_interface,
 564         .swd_ops = &bitbang_swd,
 565 };
 566
 567 static struct bitbang_interface sysfsgpio_bitbang = {
 568         .read = sysfsgpio_read,
 569         .write = sysfsgpio_write,
 570         .swdio_read = sysfsgpio_swdio_read,
 571         .swdio_drive = sysfsgpio_swdio_drive,
 572         .swd_write = sysfsgpio_swd_write,
 573         .blink = 0
 574 };
 575
 576 /* helper func to close and cleanup files only if they were valid/ used */
 577 static void cleanup_fd(int fd, int gpio)
 578 {
 579         if (gpio >= 0) {
 580                 if (fd >= 0)
 581                         close(fd);
 582
 583                 unexport_sysfs_gpio(gpio);
 584         }
 585 }
 586
 587 static void cleanup_all_fds(void)
 588 {
 589         cleanup_fd(tck_fd, tck_gpio);
 590         cleanup_fd(tms_fd, tms_gpio);
 591         cleanup_fd(tdi_fd, tdi_gpio);
 592         cleanup_fd(tdo_fd, tdo_gpio);
 593         cleanup_fd(trst_fd, trst_gpio);
 594         cleanup_fd(srst_fd, srst_gpio);
 595         cleanup_fd(swclk_fd, swclk_gpio);
 596         cleanup_fd(swdio_fd, swdio_gpio);
 597 }
 598
 599 static bool sysfsgpio_jtag_mode_possible(void)
 600 {
 601         if (!is_gpio_valid(tck_gpio))
 602                 return false;
 603         if (!is_gpio_valid(tms_gpio))
 604                 return false;
 605         if (!is_gpio_valid(tdi_gpio))
 606                 return false;
 607         if (!is_gpio_valid(tdo_gpio))
 608                 return false;
 609         return true;
 610 }
 611
 612 static bool sysfsgpio_swd_mode_possible(void)
 613 {
 614         if (!is_gpio_valid(swclk_gpio))
 615                 return false;
 616         if (!is_gpio_valid(swdio_gpio))
 617                 return false;
 618         return true;
 619 }
 620
 621 static int sysfsgpio_init(void)
 622 {
 623         bitbang_interface = &sysfsgpio_bitbang;
 624
 625         LOG_INFO("SysfsGPIO JTAG/SWD bitbang driver");
 626
 627         if (sysfsgpio_jtag_mode_possible()) {
 628                 if (sysfsgpio_swd_mode_possible())
 629                         LOG_INFO("JTAG and SWD modes enabled");
 630                 else
 631                         LOG_INFO("JTAG only mode enabled (specify swclk and swdio gpio to add SWD mode)");
 632         } else if (sysfsgpio_swd_mode_possible()) {
 633                 LOG_INFO("SWD only mode enabled (specify tck, tms, tdi and tdo gpios to add JTAG mode)");
 634         } else {
 635                 LOG_ERROR("Require tck, tms, tdi and tdo gpios for JTAG mode and/or swclk and swdio gpio for SWD mode");
 636                 return ERROR_JTAG_INIT_FAILED;
 637         }
 638
 639
 640         /*
 641          * Configure TDO as an input, and TDI, TCK, TMS, TRST, SRST
 642          * as outputs.  Drive TDI and TCK low, and TMS/TRST/SRST high.
 643          * For SWD, SWCLK and SWDIO are configures as output high.
 644          */
 645         if (tck_gpio >= 0) {
 646                 tck_fd = setup_sysfs_gpio(tck_gpio, 1, 0);
 647                 if (tck_fd < 0)
 648                         goto out_error;
 649         }
 650
 651         if (tms_gpio >= 0) {
 652                 tms_fd = setup_sysfs_gpio(tms_gpio, 1, 1);
 653                 if (tms_fd < 0)
 654                         goto out_error;
 655         }
 656
 657         if (tdi_gpio >= 0) {
 658                 tdi_fd = setup_sysfs_gpio(tdi_gpio, 1, 0);
 659                 if (tdi_fd < 0)
 660                         goto out_error;
 661         }
 662
 663         if (tdo_gpio >= 0) {
 664                 tdo_fd = setup_sysfs_gpio(tdo_gpio, 0, 0);
 665                 if (tdo_fd < 0)
 666                         goto out_error;
 667         }
 668
 669         /* assume active low*/
 670         if (trst_gpio >= 0) {
 671                 trst_fd = setup_sysfs_gpio(trst_gpio, 1, 1);
 672                 if (trst_fd < 0)
 673                         goto out_error;
 674         }
 675
 676         /* assume active low*/
 677         if (srst_gpio >= 0) {
 678                 srst_fd = setup_sysfs_gpio(srst_gpio, 1, 1);
 679                 if (srst_fd < 0)
 680                         goto out_error;
 681         }
 682
 683         if (swclk_gpio >= 0) {
 684                 swclk_fd = setup_sysfs_gpio(swclk_gpio, 1, 0);
 685                 if (swclk_fd < 0)
 686                         goto out_error;
 687         }
 688
 689         if (swdio_gpio >= 0) {
 690                 swdio_fd = setup_sysfs_gpio(swdio_gpio, 1, 0);
 691                 if (swdio_fd < 0)
 692                         goto out_error;
 693         }
 694
 695         return ERROR_OK;
 696
 697 out_error:
 698         cleanup_all_fds();
 699         return ERROR_JTAG_INIT_FAILED;
 700 }
 701
 702 static int sysfsgpio_quit(void)
 703 {
 704         cleanup_all_fds();
 705         return ERROR_OK;
 706 }