448 lines
11 KiB
C
448 lines
11 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Bitbang driver for Linux GPIO descriptors through libgpiod
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* Copyright (C) 2020 Antonio Borneo <borneo.antonio@gmail.com>
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*
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* Largely based on sysfsgpio driver
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* Copyright (C) 2012 by Creative Product Design, marc @ cpdesign.com.au
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* Copyright (C) 2014 by Jean-Christian de Rivaz <jc@eclis.ch>
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* Copyright (C) 2014 by Paul Fertser <fercerpav@gmail.com>
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <gpiod.h>
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#include <jtag/adapter.h>
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#include <jtag/interface.h>
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#include <transport/transport.h>
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#include "bitbang.h"
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static struct gpiod_chip *gpiod_chip[ADAPTER_GPIO_IDX_NUM] = {};
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static struct gpiod_line *gpiod_line[ADAPTER_GPIO_IDX_NUM] = {};
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static int last_swclk;
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static int last_swdio;
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static bool last_stored;
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static bool swdio_input;
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static const struct adapter_gpio_config *adapter_gpio_config;
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/*
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* Helper function to determine if gpio config is valid
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*
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* Assume here that there will be less than 10000 gpios per gpiochip, and less
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* than 1000 gpiochips.
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*/
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static bool is_gpio_config_valid(enum adapter_gpio_config_index idx)
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{
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return adapter_gpio_config[idx].chip_num >= 0
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&& adapter_gpio_config[idx].chip_num < 1000
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&& adapter_gpio_config[idx].gpio_num >= 0
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&& adapter_gpio_config[idx].gpio_num < 10000;
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}
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/* Bitbang interface read of TDO */
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static bb_value_t linuxgpiod_read(void)
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{
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int retval;
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retval = gpiod_line_get_value(gpiod_line[ADAPTER_GPIO_IDX_TDO]);
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if (retval < 0) {
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LOG_WARNING("reading tdo failed");
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return 0;
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}
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return retval ? BB_HIGH : BB_LOW;
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}
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/*
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* Bitbang interface write of TCK, TMS, TDI
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*
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* Seeing as this is the only function where the outputs are changed,
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* we can cache the old value to avoid needlessly writing it.
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*/
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static int linuxgpiod_write(int tck, int tms, int tdi)
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{
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static int last_tck;
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static int last_tms;
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static int last_tdi;
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static int first_time;
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int retval;
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if (!first_time) {
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last_tck = !tck;
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last_tms = !tms;
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last_tdi = !tdi;
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first_time = 1;
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}
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if (tdi != last_tdi) {
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retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_TDI], tdi);
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if (retval < 0)
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LOG_WARNING("writing tdi failed");
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}
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if (tms != last_tms) {
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retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_TMS], tms);
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if (retval < 0)
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LOG_WARNING("writing tms failed");
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}
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/* write clk last */
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if (tck != last_tck) {
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retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_TCK], tck);
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if (retval < 0)
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LOG_WARNING("writing tck failed");
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}
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last_tdi = tdi;
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last_tms = tms;
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last_tck = tck;
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return ERROR_OK;
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}
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static int linuxgpiod_swdio_read(void)
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{
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int retval;
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retval = gpiod_line_get_value(gpiod_line[ADAPTER_GPIO_IDX_SWDIO]);
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if (retval < 0) {
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LOG_WARNING("Fail read swdio");
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return 0;
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}
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return retval;
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}
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static void linuxgpiod_swdio_drive(bool is_output)
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{
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int retval;
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/*
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* FIXME: change direction requires release and re-require the line
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* https://stackoverflow.com/questions/58735140/
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* this would change in future libgpiod
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*/
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gpiod_line_release(gpiod_line[ADAPTER_GPIO_IDX_SWDIO]);
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if (is_output) {
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if (gpiod_line[ADAPTER_GPIO_IDX_SWDIO_DIR]) {
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retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_SWDIO_DIR], 1);
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if (retval < 0)
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LOG_WARNING("Fail set swdio_dir");
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}
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retval = gpiod_line_request_output(gpiod_line[ADAPTER_GPIO_IDX_SWDIO], "OpenOCD", 1);
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if (retval < 0)
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LOG_WARNING("Fail request_output line swdio");
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} else {
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retval = gpiod_line_request_input(gpiod_line[ADAPTER_GPIO_IDX_SWDIO], "OpenOCD");
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if (retval < 0)
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LOG_WARNING("Fail request_input line swdio");
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if (gpiod_line[ADAPTER_GPIO_IDX_SWDIO_DIR]) {
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retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_SWDIO_DIR], 0);
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if (retval < 0)
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LOG_WARNING("Fail set swdio_dir");
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}
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}
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last_stored = false;
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swdio_input = !is_output;
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}
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static int linuxgpiod_swd_write(int swclk, int swdio)
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{
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int retval;
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if (!swdio_input) {
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if (!last_stored || (swdio != last_swdio)) {
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retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_SWDIO], swdio);
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if (retval < 0)
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LOG_WARNING("Fail set swdio");
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}
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}
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/* write swclk last */
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if (!last_stored || (swclk != last_swclk)) {
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retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_SWCLK], swclk);
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if (retval < 0)
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LOG_WARNING("Fail set swclk");
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}
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last_swdio = swdio;
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last_swclk = swclk;
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last_stored = true;
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return ERROR_OK;
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}
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static int linuxgpiod_blink(int on)
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{
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int retval;
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if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_LED))
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return ERROR_OK;
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retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_LED], on);
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if (retval < 0)
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LOG_WARNING("Fail set led");
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return retval;
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}
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static struct bitbang_interface linuxgpiod_bitbang = {
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.read = linuxgpiod_read,
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.write = linuxgpiod_write,
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.swdio_read = linuxgpiod_swdio_read,
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.swdio_drive = linuxgpiod_swdio_drive,
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.swd_write = linuxgpiod_swd_write,
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.blink = linuxgpiod_blink,
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};
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/*
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* Bitbang interface to manipulate reset lines SRST and TRST
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*
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* (1) assert or (0) deassert reset lines
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*/
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static int linuxgpiod_reset(int trst, int srst)
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{
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int retval1 = 0, retval2 = 0;
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LOG_DEBUG("linuxgpiod_reset");
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/*
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* active low behaviour handled by "adaptor gpio" command and
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* GPIOD_LINE_REQUEST_FLAG_ACTIVE_LOW flag when requesting the line.
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*/
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if (gpiod_line[ADAPTER_GPIO_IDX_SRST]) {
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retval1 = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_SRST], srst);
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if (retval1 < 0)
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LOG_WARNING("set srst value failed");
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}
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if (gpiod_line[ADAPTER_GPIO_IDX_TRST]) {
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retval2 = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_TRST], trst);
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if (retval2 < 0)
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LOG_WARNING("set trst value failed");
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}
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return ((retval1 < 0) || (retval2 < 0)) ? ERROR_FAIL : ERROR_OK;
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}
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static bool linuxgpiod_jtag_mode_possible(void)
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{
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if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_TCK))
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return false;
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if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_TMS))
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return false;
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if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_TDI))
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return false;
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if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_TDO))
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return false;
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return true;
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}
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static bool linuxgpiod_swd_mode_possible(void)
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{
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if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_SWCLK))
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return false;
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if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_SWDIO))
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return false;
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return true;
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}
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static inline void helper_release(enum adapter_gpio_config_index idx)
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{
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if (gpiod_line[idx]) {
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gpiod_line_release(gpiod_line[idx]);
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gpiod_line[idx] = NULL;
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}
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if (gpiod_chip[idx]) {
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gpiod_chip_close(gpiod_chip[idx]);
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gpiod_chip[idx] = NULL;
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}
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}
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static int linuxgpiod_quit(void)
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{
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LOG_DEBUG("linuxgpiod_quit");
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for (int i = 0; i < ADAPTER_GPIO_IDX_NUM; ++i)
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helper_release(i);
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return ERROR_OK;
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}
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int helper_get_line(enum adapter_gpio_config_index idx)
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{
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if (!is_gpio_config_valid(idx))
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return ERROR_OK;
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int dir = GPIOD_LINE_REQUEST_DIRECTION_INPUT, flags = 0, val = 0, retval;
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gpiod_chip[idx] = gpiod_chip_open_by_number(adapter_gpio_config[idx].chip_num);
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if (!gpiod_chip[idx]) {
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LOG_ERROR("Cannot open LinuxGPIOD chip %d for %s", adapter_gpio_config[idx].chip_num,
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adapter_gpio_get_name(idx));
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return ERROR_JTAG_INIT_FAILED;
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}
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gpiod_line[idx] = gpiod_chip_get_line(gpiod_chip[idx], adapter_gpio_config[idx].gpio_num);
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if (!gpiod_line[idx]) {
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LOG_ERROR("Error get line %s", adapter_gpio_get_name(idx));
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return ERROR_JTAG_INIT_FAILED;
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}
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switch (adapter_gpio_config[idx].init_state) {
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case ADAPTER_GPIO_INIT_STATE_INPUT:
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dir = GPIOD_LINE_REQUEST_DIRECTION_INPUT;
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break;
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case ADAPTER_GPIO_INIT_STATE_INACTIVE:
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dir = GPIOD_LINE_REQUEST_DIRECTION_OUTPUT;
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val = 0;
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break;
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case ADAPTER_GPIO_INIT_STATE_ACTIVE:
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dir = GPIOD_LINE_REQUEST_DIRECTION_OUTPUT;
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val = 1;
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break;
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}
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switch (adapter_gpio_config[idx].drive) {
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case ADAPTER_GPIO_DRIVE_MODE_PUSH_PULL:
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break;
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case ADAPTER_GPIO_DRIVE_MODE_OPEN_DRAIN:
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flags |= GPIOD_LINE_REQUEST_FLAG_OPEN_DRAIN;
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break;
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case ADAPTER_GPIO_DRIVE_MODE_OPEN_SOURCE:
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flags |= GPIOD_LINE_REQUEST_FLAG_OPEN_SOURCE;
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break;
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}
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switch (adapter_gpio_config[idx].pull) {
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case ADAPTER_GPIO_PULL_NONE:
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#ifdef GPIOD_LINE_REQUEST_FLAG_BIAS_DISABLE
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flags |= GPIOD_LINE_REQUEST_FLAG_BIAS_DISABLE;
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#endif
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break;
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case ADAPTER_GPIO_PULL_UP:
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#ifdef GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_UP
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flags |= GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_UP;
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#else
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LOG_WARNING("linuxgpiod: ignoring request for pull-up on %s: not supported by gpiod v%s",
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adapter_gpio_get_name(idx), gpiod_version_string());
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#endif
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break;
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case ADAPTER_GPIO_PULL_DOWN:
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#ifdef GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_DOWN
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flags |= GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_DOWN;
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#else
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LOG_WARNING("linuxgpiod: ignoring request for pull-down on %s: not supported by gpiod v%s",
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adapter_gpio_get_name(idx), gpiod_version_string());
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#endif
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break;
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}
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if (adapter_gpio_config[idx].active_low)
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flags |= GPIOD_LINE_REQUEST_FLAG_ACTIVE_LOW;
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struct gpiod_line_request_config config = {
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.consumer = "OpenOCD",
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.request_type = dir,
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.flags = flags,
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};
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retval = gpiod_line_request(gpiod_line[idx], &config, val);
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if (retval < 0) {
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LOG_ERROR("Error requesting gpio line %s", adapter_gpio_get_name(idx));
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return ERROR_JTAG_INIT_FAILED;
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}
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return ERROR_OK;
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}
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static int linuxgpiod_init(void)
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{
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LOG_INFO("Linux GPIOD JTAG/SWD bitbang driver");
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bitbang_interface = &linuxgpiod_bitbang;
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adapter_gpio_config = adapter_gpio_get_config();
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/*
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* Configure JTAG/SWD signals. Default directions and initial states are handled
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* by adapter.c and "adapter gpio" command.
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*/
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if (transport_is_jtag()) {
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if (!linuxgpiod_jtag_mode_possible()) {
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LOG_ERROR("Require tck, tms, tdi and tdo gpios for JTAG mode");
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goto out_error;
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}
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if (helper_get_line(ADAPTER_GPIO_IDX_TDO) != ERROR_OK ||
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helper_get_line(ADAPTER_GPIO_IDX_TDI) != ERROR_OK ||
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helper_get_line(ADAPTER_GPIO_IDX_TCK) != ERROR_OK ||
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helper_get_line(ADAPTER_GPIO_IDX_TMS) != ERROR_OK ||
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helper_get_line(ADAPTER_GPIO_IDX_TRST) != ERROR_OK)
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goto out_error;
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}
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if (transport_is_swd()) {
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int retval1, retval2;
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if (!linuxgpiod_swd_mode_possible()) {
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LOG_ERROR("Require swclk and swdio gpio for SWD mode");
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goto out_error;
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}
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/*
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* swdio and its buffer should be initialized in the order that prevents
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* two outputs from being connected together. This will occur if the
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* swdio GPIO is configured as an output while the external buffer is
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* configured to send the swdio signal from the target to the GPIO.
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*/
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if (adapter_gpio_config[ADAPTER_GPIO_IDX_SWDIO].init_state == ADAPTER_GPIO_INIT_STATE_INPUT) {
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retval1 = helper_get_line(ADAPTER_GPIO_IDX_SWDIO);
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retval2 = helper_get_line(ADAPTER_GPIO_IDX_SWDIO_DIR);
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} else {
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retval1 = helper_get_line(ADAPTER_GPIO_IDX_SWDIO_DIR);
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retval2 = helper_get_line(ADAPTER_GPIO_IDX_SWDIO);
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}
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if (retval1 != ERROR_OK || retval2 != ERROR_OK)
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goto out_error;
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if (helper_get_line(ADAPTER_GPIO_IDX_SWCLK) != ERROR_OK)
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goto out_error;
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}
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if (helper_get_line(ADAPTER_GPIO_IDX_SRST) != ERROR_OK ||
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helper_get_line(ADAPTER_GPIO_IDX_LED) != ERROR_OK)
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goto out_error;
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return ERROR_OK;
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out_error:
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linuxgpiod_quit();
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return ERROR_JTAG_INIT_FAILED;
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}
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static const char *const linuxgpiod_transport[] = { "swd", "jtag", NULL };
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static struct jtag_interface linuxgpiod_interface = {
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.supported = DEBUG_CAP_TMS_SEQ,
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.execute_queue = bitbang_execute_queue,
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};
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struct adapter_driver linuxgpiod_adapter_driver = {
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.name = "linuxgpiod",
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.transports = linuxgpiod_transport,
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.init = linuxgpiod_init,
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.quit = linuxgpiod_quit,
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.reset = linuxgpiod_reset,
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.jtag_ops = &linuxgpiod_interface,
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.swd_ops = &bitbang_swd,
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};
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