--- /dev/null
+/* 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 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 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 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 = NULL,
+};
+
+/*
+ * 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 != NULL) {
+ 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 != NULL) {
+ 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_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 == NULL) {
+ 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 == NULL) {
+ 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 == NULL) {
+ 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 == NULL)
+ goto out_error;
+
+ gpiod_tdi = helper_get_output_line("tdi", tdi_gpio, 0);
+ if (gpiod_tdi == NULL)
+ goto out_error;
+
+ gpiod_tck = helper_get_output_line("tck", tck_gpio, 0);
+ if (gpiod_tck == NULL)
+ goto out_error;
+
+ gpiod_tms = helper_get_output_line("tms", tms_gpio, 1);
+ if (gpiod_tms == NULL)
+ goto out_error;
+
+ if (is_gpio_valid(trst_gpio)) {
+ gpiod_trst = helper_get_output_line("trst", trst_gpio, 1);
+ if (gpiod_trst == NULL)
+ 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 == NULL)
+ goto out_error;
+
+ gpiod_swdio = helper_get_output_line("swdio", swdio_gpio, 1);
+ if (gpiod_swdio == NULL)
+ goto out_error;
+ }
+
+ if (is_gpio_valid(srst_gpio)) {
+ gpiod_srst = helper_get_output_line("srst", srst_gpio, 1);
+ if (gpiod_srst == NULL)
+ 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_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_command_handlers[] = {
+ {
+ .name = "linuxgpiod_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 = "linuxgpiod_tck_num",
+ .handler = linuxgpiod_handle_jtag_gpionum_tck,
+ .mode = COMMAND_CONFIG,
+ .help = "gpio number for tck.",
+ .usage = "tck",
+ },
+ {
+ .name = "linuxgpiod_tms_num",
+ .handler = linuxgpiod_handle_jtag_gpionum_tms,
+ .mode = COMMAND_CONFIG,
+ .help = "gpio number for tms.",
+ .usage = "tms",
+ },
+ {
+ .name = "linuxgpiod_tdo_num",
+ .handler = linuxgpiod_handle_jtag_gpionum_tdo,
+ .mode = COMMAND_CONFIG,
+ .help = "gpio number for tdo.",
+ .usage = "tdo",
+ },
+ {
+ .name = "linuxgpiod_tdi_num",
+ .handler = linuxgpiod_handle_jtag_gpionum_tdi,
+ .mode = COMMAND_CONFIG,
+ .help = "gpio number for tdi.",
+ .usage = "tdi",
+ },
+ {
+ .name = "linuxgpiod_srst_num",
+ .handler = linuxgpiod_handle_jtag_gpionum_srst,
+ .mode = COMMAND_CONFIG,
+ .help = "gpio number for srst.",
+ .usage = "srst",
+ },
+ {
+ .name = "linuxgpiod_trst_num",
+ .handler = linuxgpiod_handle_jtag_gpionum_trst,
+ .mode = COMMAND_CONFIG,
+ .help = "gpio number for trst.",
+ .usage = "trst",
+ },
+ {
+ .name = "linuxgpiod_swd_nums",
+ .handler = linuxgpiod_handle_swd_gpionums,
+ .mode = COMMAND_CONFIG,
+ .help = "gpio numbers for swclk, swdio. (in that order)",
+ .usage = "swclk swdio",
+ },
+ {
+ .name = "linuxgpiod_swclk_num",
+ .handler = linuxgpiod_handle_swd_gpionum_swclk,
+ .mode = COMMAND_CONFIG,
+ .help = "gpio number for swclk.",
+ .usage = "swclk",
+ },
+ {
+ .name = "linuxgpiod_swdio_num",
+ .handler = linuxgpiod_handle_swd_gpionum_swdio,
+ .mode = COMMAND_CONFIG,
+ .help = "gpio number for swdio.",
+ .usage = "swdio",
+ },
+ {
+ .name = "linuxgpiod_gpiochip",
+ .handler = linuxgpiod_handle_gpiochip,
+ .mode = COMMAND_CONFIG,
+ .help = "number of the gpiochip.",
+ .usage = "gpiochip",
+ },
+ 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,
+};
projects / fw / openocd / commitdiff