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/* 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 != 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_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 == 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;
}
if (is_gpio_valid(led_gpio)) {
gpiod_led = helper_get_output_line("led", led_gpio, 0);
if (gpiod_led == 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_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_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_led_num",
.handler = linuxgpiod_handle_gpionum_led,
.mode = COMMAND_CONFIG,
.help = "gpio number for LED.",
.usage = "led",
},
{
.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,
};
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