- /* SPDX-License-Identifier: GPL-2.0-or-later */
- /*
- * Bitbang driver for Linux GPIO descriptors through libgpiod
- * Copyright (C) 2020 Antonio Borneo <borneo.antonio@gmail.com>
- *
- * Largely based on sysfsgpio driver
- * Copyright (C) 2012 by Creative Product Design, marc @ cpdesign.com.au
- * Copyright (C) 2014 by Jean-Christian de Rivaz <jc@eclis.ch>
- * Copyright (C) 2014 by Paul Fertser <fercerpav@gmail.com>
- */
-
- #ifdef HAVE_CONFIG_H
- #include "config.h"
- #endif
-
- #include <gpiod.h>
- #include <jtag/interface.h>
- #include <transport/transport.h>
- #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 led_gpio = -1;
- static int gpiochip = -1;
-
- static struct gpiod_chip *gpiod_chip;
- 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_srst;
- static struct gpiod_line *gpiod_led;
-
- static int last_swclk;
- static int last_swdio;
- static bool last_stored;
- static bool swdio_input;
-
- /* 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) {
- 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");
- }
-
- 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);
-
- gpiod_chip_close(gpiod_chip);
-
- return ERROR_OK;
- }
-
- static struct gpiod_line *helper_get_input_line(const char *label, unsigned int offset)
- {
- 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;
- }
-
- retval = gpiod_line_request_input(line, "OpenOCD");
- if (retval < 0) {
- LOG_ERROR("Error request_input line %s", label);
- return NULL;
- }
-
- return line;
- }
-
- static struct gpiod_line *helper_get_output_line(const char *label, unsigned int offset, int val)
- {
- 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;
- }
-
- retval = gpiod_line_request_output(line, "OpenOCD", val);
- if (retval < 0) {
- LOG_ERROR("Error request_output line %s", label);
- return NULL;
- }
-
- return line;
- }
-
- static int linuxgpiod_init(void)
- {
- LOG_INFO("Linux GPIOD JTAG/SWD bitbang driver");
-
- bitbang_interface = &linuxgpiod_bitbang;
-
- gpiod_chip = gpiod_chip_open_by_number(gpiochip);
- if (!gpiod_chip) {
- LOG_ERROR("Cannot open LinuxGPIOD gpiochip %d", gpiochip);
- return ERROR_JTAG_INIT_FAILED;
- }
-
- /*
- * 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_tdo = helper_get_input_line("tdo", tdo_gpio);
- if (!gpiod_tdo)
- goto out_error;
-
- gpiod_tdi = helper_get_output_line("tdi", tdi_gpio, 0);
- if (!gpiod_tdi)
- goto out_error;
-
- gpiod_tck = helper_get_output_line("tck", tck_gpio, 0);
- if (!gpiod_tck)
- goto out_error;
-
- gpiod_tms = helper_get_output_line("tms", tms_gpio, 1);
- if (!gpiod_tms)
- goto out_error;
-
- if (is_gpio_valid(trst_gpio)) {
- gpiod_trst = helper_get_output_line("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_swclk = helper_get_output_line("swclk", swclk_gpio, 1);
- if (!gpiod_swclk)
- goto out_error;
-
- gpiod_swdio = helper_get_output_line("swdio", swdio_gpio, 1);
- if (!gpiod_swdio)
- goto out_error;
- }
-
- if (is_gpio_valid(srst_gpio)) {
- gpiod_srst = helper_get_output_line("srst", srst_gpio, 1);
- if (!gpiod_srst)
- goto out_error;
- }
-
- if (is_gpio_valid(led_gpio)) {
- gpiod_led = helper_get_output_line("led", led_gpio, 0);
- if (!gpiod_led)
- goto out_error;
- }
-
- return ERROR_OK;
-
- out_error:
- linuxgpiod_quit();
-
- return ERROR_JTAG_INIT_FAILED;
- }
-
- 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)
- {
- if (CMD_ARGC == 1)
- COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], tck_gpio);
-
- command_print(CMD, "LinuxGPIOD num: tck = %d", tck_gpio);
- return ERROR_OK;
- }
-
- COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tms)
- {
- if (CMD_ARGC == 1)
- COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], tms_gpio);
-
- command_print(CMD, "LinuxGPIOD num: tms = %d", tms_gpio);
- return ERROR_OK;
- }
-
- COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tdo)
- {
- if (CMD_ARGC == 1)
- COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], tdo_gpio);
-
- command_print(CMD, "LinuxGPIOD num: tdo = %d", tdo_gpio);
- return ERROR_OK;
- }
-
- COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tdi)
- {
- if (CMD_ARGC == 1)
- COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], tdi_gpio);
-
- command_print(CMD, "LinuxGPIOD num: tdi = %d", tdi_gpio);
- return ERROR_OK;
- }
-
- COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_srst)
- {
- if (CMD_ARGC == 1)
- COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], srst_gpio);
-
- command_print(CMD, "LinuxGPIOD num: srst = %d", srst_gpio);
- return ERROR_OK;
- }
-
- COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_trst)
- {
- if (CMD_ARGC == 1)
- COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], trst_gpio);
-
- command_print(CMD, "LinuxGPIOD num: trst = %d", trst_gpio);
- return ERROR_OK;
- }
-
- 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)
- {
- if (CMD_ARGC == 1)
- COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swclk_gpio);
-
- command_print(CMD, "LinuxGPIOD num: swclk = %d", swclk_gpio);
- return ERROR_OK;
- }
-
- COMMAND_HANDLER(linuxgpiod_handle_swd_gpionum_swdio)
- {
- if (CMD_ARGC == 1)
- COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swdio_gpio);
-
- command_print(CMD, "LinuxGPIOD num: swdio = %d", swdio_gpio);
- return ERROR_OK;
- }
-
- COMMAND_HANDLER(linuxgpiod_handle_gpionum_led)
- {
- if (CMD_ARGC == 1)
- COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], led_gpio);
-
- command_print(CMD, "LinuxGPIOD num: led = %d", led_gpio);
- return ERROR_OK;
- }
-
- COMMAND_HANDLER(linuxgpiod_handle_gpiochip)
- {
- if (CMD_ARGC == 1)
- COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], 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 number for tck.",
- .usage = "tck",
- },
- {
- .name = "tms_num",
- .handler = linuxgpiod_handle_jtag_gpionum_tms,
- .mode = COMMAND_CONFIG,
- .help = "gpio number for tms.",
- .usage = "tms",
- },
- {
- .name = "tdo_num",
- .handler = linuxgpiod_handle_jtag_gpionum_tdo,
- .mode = COMMAND_CONFIG,
- .help = "gpio number for tdo.",
- .usage = "tdo",
- },
- {
- .name = "tdi_num",
- .handler = linuxgpiod_handle_jtag_gpionum_tdi,
- .mode = COMMAND_CONFIG,
- .help = "gpio number for tdi.",
- .usage = "tdi",
- },
- {
- .name = "srst_num",
- .handler = linuxgpiod_handle_jtag_gpionum_srst,
- .mode = COMMAND_CONFIG,
- .help = "gpio number for srst.",
- .usage = "srst",
- },
- {
- .name = "trst_num",
- .handler = linuxgpiod_handle_jtag_gpionum_trst,
- .mode = COMMAND_CONFIG,
- .help = "gpio number for trst.",
- .usage = "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 number for swclk.",
- .usage = "swclk",
- },
- {
- .name = "swdio_num",
- .handler = linuxgpiod_handle_swd_gpionum_swdio,
- .mode = COMMAND_CONFIG,
- .help = "gpio number for swdio.",
- .usage = "swdio",
- },
- {
- .name = "led_num",
- .handler = linuxgpiod_handle_gpionum_led,
- .mode = COMMAND_CONFIG,
- .help = "gpio number for LED.",
- .usage = "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,
- };
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