/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * Bitbang driver for Linux GPIO descriptors through libgpiod * Copyright (C) 2020 Antonio Borneo * * Largely based on sysfsgpio driver * Copyright (C) 2012 by Creative Product Design, marc @ cpdesign.com.au * Copyright (C) 2014 by Jean-Christian de Rivaz * Copyright (C) 2014 by Paul Fertser */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include #include "bitbang.h" /* gpio numbers for each gpio. Negative values are invalid */ static int tck_gpio = -1; static int tms_gpio = -1; static int tdi_gpio = -1; static int tdo_gpio = -1; static int trst_gpio = -1; static int srst_gpio = -1; static int swclk_gpio = -1; static int swdio_gpio = -1; static int swdio_dir_gpio = -1; static int led_gpio = -1; static int gpiochip = -1; static int tck_gpiochip = -1; static int tms_gpiochip = -1; static int tdi_gpiochip = -1; static int tdo_gpiochip = -1; static int trst_gpiochip = -1; static int srst_gpiochip = -1; static int swclk_gpiochip = -1; static int swdio_gpiochip = -1; static int swdio_dir_gpiochip = -1; static int led_gpiochip = -1; static struct gpiod_chip *gpiod_chip_tck; static struct gpiod_chip *gpiod_chip_tms; static struct gpiod_chip *gpiod_chip_tdi; static struct gpiod_chip *gpiod_chip_tdo; static struct gpiod_chip *gpiod_chip_trst; static struct gpiod_chip *gpiod_chip_srst; static struct gpiod_chip *gpiod_chip_swclk; static struct gpiod_chip *gpiod_chip_swdio; static struct gpiod_chip *gpiod_chip_swdio_dir; static struct gpiod_chip *gpiod_chip_led; static struct gpiod_line *gpiod_tck; static struct gpiod_line *gpiod_tms; static struct gpiod_line *gpiod_tdi; static struct gpiod_line *gpiod_tdo; static struct gpiod_line *gpiod_trst; static struct gpiod_line *gpiod_swclk; static struct gpiod_line *gpiod_swdio; static struct gpiod_line *gpiod_swdio_dir; static struct gpiod_line *gpiod_srst; static struct gpiod_line *gpiod_led; static int last_swclk; static int last_swdio; static bool last_stored; static bool swdio_input; static bool swdio_dir_is_active_high = true; /* Bitbang interface read of TDO */ static bb_value_t linuxgpiod_read(void) { int retval; retval = gpiod_line_get_value(gpiod_tdo); if (retval < 0) { LOG_WARNING("reading tdo failed"); return 0; } return retval ? BB_HIGH : BB_LOW; } /* * Bitbang interface write of TCK, TMS, TDI * * Seeing as this is the only function where the outputs are changed, * we can cache the old value to avoid needlessly writing it. */ static int linuxgpiod_write(int tck, int tms, int tdi) { static int last_tck; static int last_tms; static int last_tdi; static int first_time; int retval; if (!first_time) { last_tck = !tck; last_tms = !tms; last_tdi = !tdi; first_time = 1; } if (tdi != last_tdi) { retval = gpiod_line_set_value(gpiod_tdi, tdi); if (retval < 0) LOG_WARNING("writing tdi failed"); } if (tms != last_tms) { retval = gpiod_line_set_value(gpiod_tms, tms); if (retval < 0) LOG_WARNING("writing tms failed"); } /* write clk last */ if (tck != last_tck) { retval = gpiod_line_set_value(gpiod_tck, tck); if (retval < 0) LOG_WARNING("writing tck failed"); } last_tdi = tdi; last_tms = tms; last_tck = tck; return ERROR_OK; } static int linuxgpiod_swdio_read(void) { int retval; retval = gpiod_line_get_value(gpiod_swdio); if (retval < 0) { LOG_WARNING("Fail read swdio"); return 0; } return retval; } static void linuxgpiod_swdio_drive(bool is_output) { int retval; /* * FIXME: change direction requires release and re-require the line * https://stackoverflow.com/questions/58735140/ * this would change in future libgpiod */ gpiod_line_release(gpiod_swdio); if (is_output) { if (gpiod_swdio_dir) { retval = gpiod_line_set_value(gpiod_swdio_dir, swdio_dir_is_active_high ? 1 : 0); if (retval < 0) LOG_WARNING("Fail set swdio_dir"); } retval = gpiod_line_request_output(gpiod_swdio, "OpenOCD", 1); if (retval < 0) LOG_WARNING("Fail request_output line swdio"); } else { retval = gpiod_line_request_input(gpiod_swdio, "OpenOCD"); if (retval < 0) LOG_WARNING("Fail request_input line swdio"); if (gpiod_swdio_dir) { retval = gpiod_line_set_value(gpiod_swdio_dir, swdio_dir_is_active_high ? 0 : 1); if (retval < 0) LOG_WARNING("Fail set swdio_dir"); } } last_stored = false; swdio_input = !is_output; } static int linuxgpiod_swd_write(int swclk, int swdio) { int retval; if (!swdio_input) { if (!last_stored || (swdio != last_swdio)) { retval = gpiod_line_set_value(gpiod_swdio, swdio); if (retval < 0) LOG_WARNING("Fail set swdio"); } } /* write swclk last */ if (!last_stored || (swclk != last_swclk)) { retval = gpiod_line_set_value(gpiod_swclk, swclk); if (retval < 0) LOG_WARNING("Fail set swclk"); } last_swdio = swdio; last_swclk = swclk; last_stored = true; return ERROR_OK; } static int linuxgpiod_blink(int on) { int retval; if (!gpiod_led) return ERROR_OK; retval = gpiod_line_set_value(gpiod_led, on); if (retval < 0) LOG_WARNING("Fail set led"); return retval; } static struct bitbang_interface linuxgpiod_bitbang = { .read = linuxgpiod_read, .write = linuxgpiod_write, .swdio_read = linuxgpiod_swdio_read, .swdio_drive = linuxgpiod_swdio_drive, .swd_write = linuxgpiod_swd_write, .blink = linuxgpiod_blink, }; /* * Bitbang interface to manipulate reset lines SRST and TRST * * (1) assert or (0) deassert reset lines */ static int linuxgpiod_reset(int trst, int srst) { int retval1 = 0, retval2 = 0; LOG_DEBUG("linuxgpiod_reset"); /* assume active low */ if (gpiod_srst) { retval1 = gpiod_line_set_value(gpiod_srst, srst ? 0 : 1); if (retval1 < 0) LOG_WARNING("set srst value failed"); } /* assume active low */ if (gpiod_trst) { retval2 = gpiod_line_set_value(gpiod_trst, trst ? 0 : 1); if (retval2 < 0) LOG_WARNING("set trst value failed"); } return ((retval1 < 0) || (retval2 < 0)) ? ERROR_FAIL : ERROR_OK; } /* * Helper function to determine if gpio number is valid * * Assume here that there will be less than 10000 gpios per gpiochip */ static bool is_gpio_valid(int gpio) { return gpio >= 0 && gpio < 10000; } static bool linuxgpiod_jtag_mode_possible(void) { if (!is_gpio_valid(tck_gpio)) return false; if (!is_gpio_valid(tms_gpio)) return false; if (!is_gpio_valid(tdi_gpio)) return false; if (!is_gpio_valid(tdo_gpio)) return false; return true; } static bool linuxgpiod_swd_mode_possible(void) { if (!is_gpio_valid(swclk_gpio)) return false; if (!is_gpio_valid(swdio_gpio)) return false; return true; } static inline void helper_release(struct gpiod_line *line) { if (line) gpiod_line_release(line); } static int linuxgpiod_quit(void) { helper_release(gpiod_led); helper_release(gpiod_srst); helper_release(gpiod_swdio); helper_release(gpiod_swclk); helper_release(gpiod_trst); helper_release(gpiod_tms); helper_release(gpiod_tck); helper_release(gpiod_tdi); helper_release(gpiod_tdo); if (gpiod_chip_led != NULL) gpiod_chip_close(gpiod_chip_led); if (gpiod_chip_srst != NULL) gpiod_chip_close(gpiod_chip_srst); if (gpiod_chip_swdio != NULL) gpiod_chip_close(gpiod_chip_swdio); if (gpiod_chip_swdio_dir != NULL) gpiod_chip_close(gpiod_chip_swdio_dir); if (gpiod_chip_swclk != NULL) gpiod_chip_close(gpiod_chip_swclk); if (gpiod_chip_trst != NULL) gpiod_chip_close(gpiod_chip_trst); if (gpiod_chip_tms != NULL) gpiod_chip_close(gpiod_chip_tms); if (gpiod_chip_tck != NULL) gpiod_chip_close(gpiod_chip_tck); if (gpiod_chip_tdi != NULL) gpiod_chip_close(gpiod_chip_tdi); if (gpiod_chip_tdo != NULL) gpiod_chip_close(gpiod_chip_tdo); return ERROR_OK; } static struct gpiod_line *helper_get_line(const char *label, struct gpiod_chip *gpiod_chip, unsigned int offset, int val, int dir, int flags) { struct gpiod_line *line; int retval; line = gpiod_chip_get_line(gpiod_chip, offset); if (!line) { LOG_ERROR("Error get line %s", label); return NULL; } struct gpiod_line_request_config config = { .consumer = "OpenOCD", .request_type = dir, .flags = flags, }; retval = gpiod_line_request(line, &config, val); if (retval < 0) { LOG_ERROR("Error requesting gpio line %s", label); return NULL; } return line; } static struct gpiod_line *helper_get_input_line(const char *label, struct gpiod_chip *gpiod_chip, unsigned int offset) { return helper_get_line(label, gpiod_chip, offset, 0, GPIOD_LINE_REQUEST_DIRECTION_INPUT, 0); } static struct gpiod_line *helper_get_output_line(const char *label, struct gpiod_chip *gpiod_chip, unsigned int offset, int val) { return helper_get_line(label, gpiod_chip, offset, val, GPIOD_LINE_REQUEST_DIRECTION_OUTPUT, 0); } static struct gpiod_line *helper_get_open_drain_output_line(const char *label, struct gpiod_chip *gpiod_chip, unsigned int offset, int val) { return helper_get_line(label, gpiod_chip, offset, val, GPIOD_LINE_REQUEST_DIRECTION_OUTPUT, GPIOD_LINE_REQUEST_FLAG_OPEN_DRAIN); } static int linuxgpiod_init(void) { LOG_INFO("Linux GPIOD JTAG/SWD bitbang driver"); bitbang_interface = &linuxgpiod_bitbang; /* * Configure TDO as an input, and TDI, TCK, TMS, TRST, SRST * as outputs. Drive TDI and TCK low, and TMS/TRST/SRST high. * For SWD, SWCLK and SWDIO are configures as output high. */ if (transport_is_jtag()) { if (!linuxgpiod_jtag_mode_possible()) { LOG_ERROR("Require tck, tms, tdi and tdo gpios for JTAG mode"); goto out_error; } gpiod_chip_tdo = gpiod_chip_open_by_number(tdo_gpiochip); if (!gpiod_chip_tdo) { LOG_ERROR("Cannot open LinuxGPIOD tdo_gpiochip %d", tdo_gpiochip); goto out_error; } gpiod_chip_tdi = gpiod_chip_open_by_number(tdi_gpiochip); if (!gpiod_chip_tdi) { LOG_ERROR("Cannot open LinuxGPIOD tdi_gpiochip %d", tdi_gpiochip); goto out_error; } gpiod_chip_tck = gpiod_chip_open_by_number(tck_gpiochip); if (!gpiod_chip_tck) { LOG_ERROR("Cannot open LinuxGPIOD tck_gpiochip %d", tck_gpiochip); goto out_error; } gpiod_chip_tms = gpiod_chip_open_by_number(tms_gpiochip); if (!gpiod_chip_tms) { LOG_ERROR("Cannot open LinuxGPIOD tms_gpiochip %d", tms_gpiochip); goto out_error; } gpiod_tdo = helper_get_input_line("tdo", gpiod_chip_tdo, tdo_gpio); if (!gpiod_tdo) goto out_error; gpiod_tdi = helper_get_output_line("tdi", gpiod_chip_tdi, tdi_gpio, 0); if (!gpiod_tdi) goto out_error; gpiod_tck = helper_get_output_line("tck", gpiod_chip_tck, tck_gpio, 0); if (!gpiod_tck) goto out_error; gpiod_tms = helper_get_output_line("tms", gpiod_chip_tms, tms_gpio, 1); if (!gpiod_tms) goto out_error; if (is_gpio_valid(trst_gpio)) { gpiod_chip_trst = gpiod_chip_open_by_number(trst_gpiochip); if (!gpiod_chip_trst) { LOG_ERROR("Cannot open LinuxGPIOD trst_gpiochip %d", trst_gpiochip); goto out_error; } if (jtag_get_reset_config() & RESET_TRST_OPEN_DRAIN) gpiod_trst = helper_get_open_drain_output_line("trst", gpiod_chip_trst, trst_gpio, 1); else gpiod_trst = helper_get_output_line("trst", gpiod_chip_trst, trst_gpio, 1); if (!gpiod_trst) goto out_error; } } if (transport_is_swd()) { if (!linuxgpiod_swd_mode_possible()) { LOG_ERROR("Require swclk and swdio gpio for SWD mode"); goto out_error; } gpiod_chip_swclk = gpiod_chip_open_by_number(swclk_gpiochip); if (!gpiod_chip_swclk) { LOG_ERROR("Cannot open LinuxGPIOD swclk_gpiochip %d", swclk_gpiochip); goto out_error; } gpiod_chip_swdio = gpiod_chip_open_by_number(swdio_gpiochip); if (!gpiod_chip_swdio) { LOG_ERROR("Cannot open LinuxGPIOD swdio_gpiochip %d", swdio_gpiochip); goto out_error; } if (is_gpio_valid(swdio_dir_gpio)) { gpiod_chip_swdio_dir = gpiod_chip_open_by_number(swdio_dir_gpiochip); if (!gpiod_chip_swdio_dir) { LOG_ERROR("Cannot open LinuxGPIOD swdio_dir_gpiochip %d", swdio_dir_gpiochip); goto out_error; } } gpiod_swclk = helper_get_output_line("swclk", gpiod_chip_swclk, swclk_gpio, 1); if (!gpiod_swclk) goto out_error; /* Set buffer direction before making SWDIO an output */ if (is_gpio_valid(swdio_dir_gpio)) { gpiod_swdio_dir = helper_get_output_line("swdio_dir", gpiod_chip_swdio_dir, swdio_dir_gpio, swdio_dir_is_active_high ? 1 : 0); if (!gpiod_swdio_dir) goto out_error; } gpiod_swdio = helper_get_output_line("swdio", gpiod_chip_swdio, swdio_gpio, 1); if (!gpiod_swdio) goto out_error; } if (is_gpio_valid(srst_gpio)) { gpiod_chip_srst = gpiod_chip_open_by_number(srst_gpiochip); if (!gpiod_chip_srst) { LOG_ERROR("Cannot open LinuxGPIOD srst_gpiochip %d", srst_gpiochip); goto out_error; } if (jtag_get_reset_config() & RESET_SRST_PUSH_PULL) gpiod_srst = helper_get_output_line("srst", gpiod_chip_srst, srst_gpio, 1); else gpiod_srst = helper_get_open_drain_output_line("srst", gpiod_chip_srst, srst_gpio, 1); if (!gpiod_srst) goto out_error; } if (is_gpio_valid(led_gpio)) { gpiod_chip_led = gpiod_chip_open_by_number(led_gpiochip); if (!gpiod_chip_led) { LOG_ERROR("Cannot open LinuxGPIOD led_gpiochip %d", led_gpiochip); goto out_error; } gpiod_led = helper_get_output_line("led", gpiod_chip_led, led_gpio, 0); if (!gpiod_led) goto out_error; } return ERROR_OK; out_error: linuxgpiod_quit(); return ERROR_JTAG_INIT_FAILED; } COMMAND_HELPER(linuxgpiod_helper_gpionum, const char *name, int *chip, int *line) { int i = 0; if (CMD_ARGC > 2) return ERROR_COMMAND_SYNTAX_ERROR; if (CMD_ARGC == 2) { COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], *chip); i = 1; } if (CMD_ARGC > 0) COMMAND_PARSE_NUMBER(int, CMD_ARGV[i], *line); command_print(CMD, "LinuxGPIOD %s: chip = %d, num = %d", name, *chip, *line); return ERROR_OK; } COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionums) { if (CMD_ARGC == 4) { COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], tck_gpio); COMMAND_PARSE_NUMBER(int, CMD_ARGV[1], tms_gpio); COMMAND_PARSE_NUMBER(int, CMD_ARGV[2], tdi_gpio); COMMAND_PARSE_NUMBER(int, CMD_ARGV[3], tdo_gpio); } else if (CMD_ARGC != 0) { return ERROR_COMMAND_SYNTAX_ERROR; } command_print(CMD, "LinuxGPIOD nums: tck = %d, tms = %d, tdi = %d, tdo = %d", tck_gpio, tms_gpio, tdi_gpio, tdo_gpio); return ERROR_OK; } COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tck) { return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "tck", &tck_gpiochip, &tck_gpio); } COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tms) { return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "tms", &tms_gpiochip, &tms_gpio); } COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tdo) { return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "tdo", &tdo_gpiochip, &tdo_gpio); } COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tdi) { return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "tdi", &tdi_gpiochip, &tdi_gpio); } COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_srst) { return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "srst", &srst_gpiochip, &srst_gpio); } COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_trst) { return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "trst", &trst_gpiochip, &trst_gpio); } COMMAND_HANDLER(linuxgpiod_handle_swd_gpionums) { if (CMD_ARGC == 2) { COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swclk_gpio); COMMAND_PARSE_NUMBER(int, CMD_ARGV[1], swdio_gpio); } else if (CMD_ARGC != 0) { return ERROR_COMMAND_SYNTAX_ERROR; } command_print(CMD, "LinuxGPIOD nums: swclk = %d, swdio = %d", swclk_gpio, swdio_gpio); return ERROR_OK; } COMMAND_HANDLER(linuxgpiod_handle_swd_gpionum_swclk) { return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "swclk", &swclk_gpiochip, &swclk_gpio); } COMMAND_HANDLER(linuxgpiod_handle_swd_gpionum_swdio) { return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "swdio", &swdio_gpiochip, &swdio_gpio); } COMMAND_HANDLER(linuxgpiod_handle_swd_gpionum_swdio_dir) { return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "swdio_dir", &swdio_dir_gpiochip, &swdio_dir_gpio); } COMMAND_HANDLER(linuxgpiod_handle_gpionum_led) { return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "led", &led_gpiochip, &led_gpio); } COMMAND_HANDLER(linuxgpiod_handle_gpiochip) { if (CMD_ARGC == 1) { COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], gpiochip); tck_gpiochip = gpiochip; tms_gpiochip = gpiochip; tdi_gpiochip = gpiochip; tdo_gpiochip = gpiochip; trst_gpiochip = gpiochip; srst_gpiochip = gpiochip; swclk_gpiochip = gpiochip; swdio_gpiochip = gpiochip; swdio_dir_gpiochip = gpiochip; led_gpiochip = gpiochip; } command_print(CMD, "LinuxGPIOD gpiochip = %d", gpiochip); return ERROR_OK; } static const struct command_registration linuxgpiod_subcommand_handlers[] = { { .name = "jtag_nums", .handler = linuxgpiod_handle_jtag_gpionums, .mode = COMMAND_CONFIG, .help = "gpio numbers for tck, tms, tdi, tdo. (in that order)", .usage = "tck tms tdi tdo", }, { .name = "tck_num", .handler = linuxgpiod_handle_jtag_gpionum_tck, .mode = COMMAND_CONFIG, .help = "gpio chip number (optional) and gpio number for tck.", .usage = "[chip] tck", }, { .name = "tms_num", .handler = linuxgpiod_handle_jtag_gpionum_tms, .mode = COMMAND_CONFIG, .help = "gpio chip number (optional) and gpio number for tms.", .usage = "[chip] tms", }, { .name = "tdo_num", .handler = linuxgpiod_handle_jtag_gpionum_tdo, .mode = COMMAND_CONFIG, .help = "gpio chip number (optional) and gpio number for tdo.", .usage = "[chip] tdo", }, { .name = "tdi_num", .handler = linuxgpiod_handle_jtag_gpionum_tdi, .mode = COMMAND_CONFIG, .help = "gpio chip number (optional) and gpio number for tdi.", .usage = "[chip] tdi", }, { .name = "srst_num", .handler = linuxgpiod_handle_jtag_gpionum_srst, .mode = COMMAND_CONFIG, .help = "gpio chip number (optional) and gpio number for srst.", .usage = "[chip] srst", }, { .name = "trst_num", .handler = linuxgpiod_handle_jtag_gpionum_trst, .mode = COMMAND_CONFIG, .help = "gpio chip number (optional) and gpio number for trst.", .usage = "[chip] trst", }, { .name = "swd_nums", .handler = linuxgpiod_handle_swd_gpionums, .mode = COMMAND_CONFIG, .help = "gpio numbers for swclk, swdio. (in that order)", .usage = "swclk swdio", }, { .name = "swclk_num", .handler = linuxgpiod_handle_swd_gpionum_swclk, .mode = COMMAND_CONFIG, .help = "gpio chip number (optional) and gpio number for swclk.", .usage = "[chip] swclk", }, { .name = "swdio_num", .handler = linuxgpiod_handle_swd_gpionum_swdio, .mode = COMMAND_CONFIG, .help = "gpio chip number (optional) and gpio number for swdio.", .usage = "[chip] swdio", }, { .name = "swdio_dir_num", .handler = linuxgpiod_handle_swd_gpionum_swdio_dir, .mode = COMMAND_CONFIG, .help = "gpio chip number (optional) and gpio number for swdio_dir.", .usage = "[chip] swdio_dir", }, { .name = "led_num", .handler = linuxgpiod_handle_gpionum_led, .mode = COMMAND_CONFIG, .help = "gpio chip number (optional) and gpio number for LED.", .usage = "[chip] led", }, { .name = "gpiochip", .handler = linuxgpiod_handle_gpiochip, .mode = COMMAND_CONFIG, .help = "number of the gpiochip.", .usage = "gpiochip", }, COMMAND_REGISTRATION_DONE }; static const struct command_registration linuxgpiod_command_handlers[] = { { .name = "linuxgpiod", .mode = COMMAND_ANY, .help = "perform linuxgpiod management", .chain = linuxgpiod_subcommand_handlers, .usage = "", }, COMMAND_REGISTRATION_DONE }; static const char *const linuxgpiod_transport[] = { "swd", "jtag", NULL }; static struct jtag_interface linuxgpiod_interface = { .supported = DEBUG_CAP_TMS_SEQ, .execute_queue = bitbang_execute_queue, }; struct adapter_driver linuxgpiod_adapter_driver = { .name = "linuxgpiod", .transports = linuxgpiod_transport, .commands = linuxgpiod_command_handlers, .init = linuxgpiod_init, .quit = linuxgpiod_quit, .reset = linuxgpiod_reset, .jtag_ops = &linuxgpiod_interface, .swd_ops = &bitbang_swd, };