This driver implements a bitbang jtag interface using gpio lines via sysfs. More...

Include dependency graph for sysfsgpio.c:

Functions
static void	cleanup_all_fds (void)

static void	cleanup_fd (int fd, int gpio)

	COMMAND_HANDLER (sysfsgpio_handle_jtag_gpionum_srst)

	COMMAND_HANDLER (sysfsgpio_handle_jtag_gpionum_tck)

	COMMAND_HANDLER (sysfsgpio_handle_jtag_gpionum_tdi)

	COMMAND_HANDLER (sysfsgpio_handle_jtag_gpionum_tdo)

	COMMAND_HANDLER (sysfsgpio_handle_jtag_gpionum_tms)

	COMMAND_HANDLER (sysfsgpio_handle_jtag_gpionum_trst)

	COMMAND_HANDLER (sysfsgpio_handle_jtag_gpionums)

	COMMAND_HANDLER (sysfsgpio_handle_swd_gpionum_swclk)

	COMMAND_HANDLER (sysfsgpio_handle_swd_gpionum_swdio)

	COMMAND_HANDLER (sysfsgpio_handle_swd_gpionums)

static bool	is_gpio_valid (int gpio)

static int	open_write_close (const char name, const char valstr)

static int	setup_sysfs_gpio (int gpio, int is_output, int init_high)

static int	sysfsgpio_init (void)

static bool	sysfsgpio_jtag_mode_possible (void)

static int	sysfsgpio_quit (void)

static bb_value_t	sysfsgpio_read (void)

static int	sysfsgpio_reset (int trst, int srst)

static bool	sysfsgpio_swd_mode_possible (void)

static int	sysfsgpio_swd_write (int swclk, int swdio)

static void	sysfsgpio_swdio_drive (bool is_output)

static int	sysfsgpio_swdio_read (void)

static int	sysfsgpio_write (int tck, int tms, int tdi)

static void	unexport_sysfs_gpio (int gpio)

Variables
static bool	last_stored

static int	last_swclk

static int	last_swdio

static int	srst_fd = -1

static int	srst_gpio = -1

static int	swclk_fd = -1

static int	swclk_gpio = -1

static int	swdio_fd = -1

static int	swdio_gpio = -1

static bool	swdio_input

struct adapter_driver	sysfsgpio_adapter_driver

static struct bitbang_interface	sysfsgpio_bitbang

static const struct command_registration	sysfsgpio_command_handlers []

static struct jtag_interface	sysfsgpio_interface

static const struct command_registration	sysfsgpio_subcommand_handlers []

static const char *const	sysfsgpio_transports [] = { "jtag", "swd", NULL }

static int	tck_fd = -1

static int	tck_gpio = -1

static int	tdi_fd = -1

static int	tdi_gpio = -1

static int	tdo_fd = -1

static int	tdo_gpio = -1

static int	tms_fd = -1

static int	tms_gpio = -1

static int	trst_fd = -1

static int	trst_gpio = -1

Detailed Description

This driver implements a bitbang jtag interface using gpio lines via sysfs.

The aim of this driver implementation is use system GPIOs but avoid the need for a additional kernel driver. (Note memory mapped IO is another option, however it doesn't mix well with the kernel gpiolib driver - which makes sense I guess.)

A gpio is required for tck, tms, tdi and tdo. One or both of srst and trst must be also be specified. The required jtag gpios are specified via the sysfsgpio_jtag_nums command or the relevant sysfsgpio_XXX_num commands. The srst and trst gpios are set via the sysfsgpio_srst_num and sysfsgpio_trst_num respectively. GPIO numbering follows the kernel convention of starting from 0.

The gpios should not be in use by another entity, and must not be requested by a kernel driver without also being exported by it (otherwise they can't be exported by sysfs).

The sysfs gpio interface can only manipulate one gpio at a time, so the bitbang write handler remembers the last state for tck, tms, tdi to avoid superfluous writes. For speed the sysfs "value" entry is opened at init and held open. This results in considerable gains over open-write-close (45s vs 900s)

Further work could address: -srst and trst open drain/ push pull -configurable active high/low for srst & trst

Definition in file sysfsgpio.c.

Function Documentation

◆ cleanup_all_fds()

static void cleanup_all_fds ( void )

static

Definition at line 588 of file sysfsgpio.c.

References cleanup_fd(), srst_fd, srst_gpio, swclk_fd, swclk_gpio, swdio_fd, swdio_gpio, tck_fd, tck_gpio, tdi_fd, tdi_gpio, tdo_fd, tdo_gpio, tms_fd, tms_gpio, transport_is_jtag(), transport_is_swd(), trst_fd, and trst_gpio.

Referenced by sysfsgpio_init(), and sysfsgpio_quit().

◆ cleanup_fd()

static void cleanup_fd	(	int	fd,
		int	gpio
	)

static

Definition at line 578 of file sysfsgpio.c.

References unexport_sysfs_gpio().

Referenced by cleanup_all_fds().

◆ COMMAND_HANDLER() [1/10]

COMMAND_HANDLER ( sysfsgpio_handle_jtag_gpionum_srst )

Definition at line 408 of file sysfsgpio.c.

References CMD, CMD_ARGC, CMD_ARGV, COMMAND_PARSE_NUMBER, command_print(), ERROR_OK, and srst_gpio.

◆ COMMAND_HANDLER() [2/10]

COMMAND_HANDLER ( sysfsgpio_handle_jtag_gpionum_tck )

Definition at line 372 of file sysfsgpio.c.

References CMD, CMD_ARGC, CMD_ARGV, COMMAND_PARSE_NUMBER, command_print(), ERROR_OK, and tck_gpio.

◆ COMMAND_HANDLER() [3/10]

COMMAND_HANDLER ( sysfsgpio_handle_jtag_gpionum_tdi )

Definition at line 399 of file sysfsgpio.c.

References CMD, CMD_ARGC, CMD_ARGV, COMMAND_PARSE_NUMBER, command_print(), ERROR_OK, and tdi_gpio.

◆ COMMAND_HANDLER() [4/10]

COMMAND_HANDLER ( sysfsgpio_handle_jtag_gpionum_tdo )

Definition at line 390 of file sysfsgpio.c.

References CMD, CMD_ARGC, CMD_ARGV, COMMAND_PARSE_NUMBER, command_print(), ERROR_OK, and tdo_gpio.

◆ COMMAND_HANDLER() [5/10]

COMMAND_HANDLER ( sysfsgpio_handle_jtag_gpionum_tms )

Definition at line 381 of file sysfsgpio.c.

References CMD, CMD_ARGC, CMD_ARGV, COMMAND_PARSE_NUMBER, command_print(), ERROR_OK, and tms_gpio.

◆ COMMAND_HANDLER() [6/10]

COMMAND_HANDLER ( sysfsgpio_handle_jtag_gpionum_trst )

Definition at line 417 of file sysfsgpio.c.

References CMD, CMD_ARGC, CMD_ARGV, COMMAND_PARSE_NUMBER, command_print(), ERROR_OK, and trst_gpio.

◆ COMMAND_HANDLER() [7/10]

COMMAND_HANDLER ( sysfsgpio_handle_jtag_gpionums )

Definition at line 354 of file sysfsgpio.c.

References CMD, CMD_ARGC, CMD_ARGV, COMMAND_PARSE_NUMBER, command_print(), ERROR_COMMAND_SYNTAX_ERROR, ERROR_OK, tck_gpio, tdi_gpio, tdo_gpio, and tms_gpio.

◆ COMMAND_HANDLER() [8/10]

COMMAND_HANDLER ( sysfsgpio_handle_swd_gpionum_swclk )

Definition at line 442 of file sysfsgpio.c.

References CMD, CMD_ARGC, CMD_ARGV, COMMAND_PARSE_NUMBER, command_print(), ERROR_OK, and swclk_gpio.

◆ COMMAND_HANDLER() [9/10]

COMMAND_HANDLER ( sysfsgpio_handle_swd_gpionum_swdio )

Definition at line 451 of file sysfsgpio.c.

References CMD, CMD_ARGC, CMD_ARGV, COMMAND_PARSE_NUMBER, command_print(), ERROR_OK, and swdio_gpio.

◆ COMMAND_HANDLER() [10/10]

COMMAND_HANDLER ( sysfsgpio_handle_swd_gpionums )

Definition at line 426 of file sysfsgpio.c.

References CMD, CMD_ARGC, CMD_ARGV, COMMAND_PARSE_NUMBER, command_print(), ERROR_COMMAND_SYNTAX_ERROR, ERROR_OK, swclk_gpio, and swdio_gpio.

◆ is_gpio_valid()

static bool is_gpio_valid ( int gpio )

static

Definition at line 54 of file sysfsgpio.c.

Referenced by setup_sysfs_gpio(), sysfsgpio_jtag_mode_possible(), sysfsgpio_swd_mode_possible(), and unexport_sysfs_gpio().

◆ open_write_close()

static int open_write_close	(	const char *	name,
		const char *	valstr
	)

static

Definition at line 65 of file sysfsgpio.c.

References name.

Referenced by setup_sysfs_gpio(), sysfsgpio_swdio_drive(), and unexport_sysfs_gpio().

◆ setup_sysfs_gpio()

static int setup_sysfs_gpio	(	int	gpio,
		int	is_output,
		int	init_high
	)

static

Definition at line 102 of file sysfsgpio.c.

References ERROR_FAIL, ERROR_OK, gettimeofday(), is_gpio_valid(), jtag_sleep(), LOG_ERROR, LOG_WARNING, NULL, open_write_close(), timeval_add_time(), timeval_compare(), and unexport_sysfs_gpio().

Referenced by sysfsgpio_init().

◆ sysfsgpio_init()

static int sysfsgpio_init ( void )

static

Definition at line 626 of file sysfsgpio.c.

References cleanup_all_fds(), ERROR_JTAG_INIT_FAILED, ERROR_OK, LOG_ERROR, LOG_INFO, setup_sysfs_gpio(), srst_fd, srst_gpio, swclk_fd, swclk_gpio, swdio_fd, swdio_gpio, sysfsgpio_bitbang, sysfsgpio_jtag_mode_possible(), sysfsgpio_swd_mode_possible(), tck_fd, tck_gpio, tdi_fd, tdi_gpio, tdo_fd, tdo_gpio, tms_fd, tms_gpio, transport_is_jtag(), transport_is_swd(), trst_fd, and trst_gpio.

◆ sysfsgpio_jtag_mode_possible()

static bool sysfsgpio_jtag_mode_possible ( void )

static

Definition at line 604 of file sysfsgpio.c.

References is_gpio_valid(), tck_gpio, tdi_gpio, tdo_gpio, and tms_gpio.

Referenced by sysfsgpio_init().

◆ sysfsgpio_quit()

static int sysfsgpio_quit ( void )

static

Definition at line 697 of file sysfsgpio.c.

References cleanup_all_fds(), and ERROR_OK.

◆ sysfsgpio_read()

static bb_value_t sysfsgpio_read ( void )

static

Definition at line 258 of file sysfsgpio.c.

References BB_HIGH, BB_LOW, LOG_WARNING, and tdo_fd.

◆ sysfsgpio_reset()

static int sysfsgpio_reset	(	int	trst,
		int	srst
	)

static

Definition at line 330 of file sysfsgpio.c.

References ERROR_OK, LOG_DEBUG, LOG_WARNING, srst_fd, trst_fd, and zero.

◆ sysfsgpio_swd_mode_possible()

static bool sysfsgpio_swd_mode_possible ( void )

static

Definition at line 617 of file sysfsgpio.c.

References is_gpio_valid(), swclk_gpio, and swdio_gpio.

Referenced by sysfsgpio_init().

◆ sysfsgpio_swd_write()

static int sysfsgpio_swd_write	(	int	swclk,
		int	swdio
	)

static

Definition at line 223 of file sysfsgpio.c.

References ERROR_OK, last_stored, last_swclk, last_swdio, LOG_WARNING, swclk_fd, swdio_fd, swdio_input, and zero.

◆ sysfsgpio_swdio_drive()

static void sysfsgpio_swdio_drive ( bool is_output )

static

Definition at line 191 of file sysfsgpio.c.

References last_stored, LOG_ERROR, open_write_close(), swdio_gpio, and swdio_input.

◆ sysfsgpio_swdio_read()

static int sysfsgpio_swdio_read ( void )

static

Definition at line 207 of file sysfsgpio.c.

References LOG_WARNING, and swdio_fd.

◆ sysfsgpio_write()

static int sysfsgpio_write	(	int	tck,
		int	tms,
		int	tdi
	)

static

Definition at line 280 of file sysfsgpio.c.

References ERROR_OK, last_tms, LOG_WARNING, tck_fd, tdi_fd, tms_fd, and zero.

◆ unexport_sysfs_gpio()

static void unexport_sysfs_gpio ( int gpio )

static

Definition at line 81 of file sysfsgpio.c.

References is_gpio_valid(), LOG_ERROR, and open_write_close().

Referenced by cleanup_fd(), and setup_sysfs_gpio().

Variable Documentation

◆ last_stored

bool last_stored

static

Definition at line 188 of file sysfsgpio.c.

Referenced by sysfsgpio_swd_write(), and sysfsgpio_swdio_drive().

◆ last_swclk

int last_swclk

static

Definition at line 186 of file sysfsgpio.c.

Referenced by sysfsgpio_swd_write().

◆ last_swdio

int last_swdio

static

Definition at line 187 of file sysfsgpio.c.

Referenced by sysfsgpio_swd_write().

◆ srst_fd

int srst_fd = -1

static

Definition at line 182 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), sysfsgpio_init(), and sysfsgpio_reset().

◆ srst_gpio

int srst_gpio = -1

static

Definition at line 169 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), COMMAND_HANDLER(), and sysfsgpio_init().

◆ swclk_fd

int swclk_fd = -1

static

Definition at line 183 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), sysfsgpio_init(), and sysfsgpio_swd_write().

◆ swclk_gpio

int swclk_gpio = -1

static

Definition at line 170 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), COMMAND_HANDLER(), sysfsgpio_init(), and sysfsgpio_swd_mode_possible().

◆ swdio_fd

int swdio_fd = -1

static

Definition at line 184 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), sysfsgpio_init(), sysfsgpio_swd_write(), and sysfsgpio_swdio_read().

◆ swdio_gpio

int swdio_gpio = -1

static

Definition at line 171 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), COMMAND_HANDLER(), sysfsgpio_init(), sysfsgpio_swd_mode_possible(), and sysfsgpio_swdio_drive().

◆ swdio_input

bool swdio_input

static

Definition at line 189 of file sysfsgpio.c.

Referenced by sysfsgpio_swd_write(), and sysfsgpio_swdio_drive().

◆ sysfsgpio_adapter_driver

struct adapter_driver sysfsgpio_adapter_driver

Initial value:

= {
    .name = "sysfsgpio",
    .transports = sysfsgpio_transports,
    .commands = sysfsgpio_command_handlers,
 
    .init = sysfsgpio_init,
    .quit = sysfsgpio_quit,
    .reset = sysfsgpio_reset,
 
    .jtag_ops = &sysfsgpio_interface,
    .swd_ops = &bitbang_swd,
}

Definition at line 548 of file sysfsgpio.c.

◆ sysfsgpio_bitbang

struct bitbang_interface sysfsgpio_bitbang

static

Initial value:

= {
    .read = sysfsgpio_read,
    .write = sysfsgpio_write,
    .swdio_read = sysfsgpio_swdio_read,
    .swdio_drive = sysfsgpio_swdio_drive,
    .swd_write = sysfsgpio_swd_write,
    .blink = NULL,
}

Definition at line 548 of file sysfsgpio.c.

Referenced by sysfsgpio_init().

◆ sysfsgpio_command_handlers

const struct command_registration sysfsgpio_command_handlers[]

static

Initial value:

= {
    {
        .name = "sysfsgpio",
        .mode = COMMAND_ANY,
        .help = "perform sysfsgpio management",
        .chain = sysfsgpio_subcommand_handlers,
        .usage = "",
    },
    COMMAND_REGISTRATION_DONE
}

Definition at line 451 of file sysfsgpio.c.

◆ sysfsgpio_interface

struct jtag_interface sysfsgpio_interface

static

Initial value:

= {
    .supported = DEBUG_CAP_TMS_SEQ,
    .execute_queue = bitbang_execute_queue,
}

Definition at line 548 of file sysfsgpio.c.

◆ sysfsgpio_subcommand_handlers

const struct command_registration sysfsgpio_subcommand_handlers[]

static

Definition at line 451 of file sysfsgpio.c.

◆ sysfsgpio_transports

const char* const sysfsgpio_transports[] = { "jtag", "swd", NULL }

static

Definition at line 548 of file sysfsgpio.c.

◆ tck_fd

int tck_fd = -1

static

Definition at line 177 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), sysfsgpio_init(), and sysfsgpio_write().

◆ tck_gpio

int tck_gpio = -1

static

Definition at line 164 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), COMMAND_HANDLER(), sysfsgpio_init(), and sysfsgpio_jtag_mode_possible().

◆ tdi_fd

int tdi_fd = -1

static

Definition at line 179 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), sysfsgpio_init(), and sysfsgpio_write().

◆ tdi_gpio

int tdi_gpio = -1

static

Definition at line 166 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), COMMAND_HANDLER(), sysfsgpio_init(), and sysfsgpio_jtag_mode_possible().

◆ tdo_fd

int tdo_fd = -1

static

Definition at line 180 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), sysfsgpio_init(), and sysfsgpio_read().

◆ tdo_gpio

int tdo_gpio = -1

static

Definition at line 167 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), COMMAND_HANDLER(), sysfsgpio_init(), and sysfsgpio_jtag_mode_possible().

◆ tms_fd

int tms_fd = -1

static

Definition at line 178 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), sysfsgpio_init(), and sysfsgpio_write().

◆ tms_gpio

int tms_gpio = -1

static

Definition at line 165 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), COMMAND_HANDLER(), sysfsgpio_init(), and sysfsgpio_jtag_mode_possible().

◆ trst_fd

int trst_fd = -1

static

Definition at line 181 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), sysfsgpio_init(), and sysfsgpio_reset().

◆ trst_gpio

int trst_gpio = -1

static

Definition at line 168 of file sysfsgpio.c.

Referenced by cleanup_all_fds(), COMMAND_HANDLER(), and sysfsgpio_init().

Functions

Variables

Detailed Description

Function Documentation

◆ cleanup_all_fds()

◆ cleanup_fd()

◆ COMMAND_HANDLER() [1/10]

◆ COMMAND_HANDLER() [2/10]

◆ COMMAND_HANDLER() [3/10]

◆ COMMAND_HANDLER() [4/10]

◆ COMMAND_HANDLER() [5/10]

◆ COMMAND_HANDLER() [6/10]

◆ COMMAND_HANDLER() [7/10]

◆ COMMAND_HANDLER() [8/10]

◆ COMMAND_HANDLER() [9/10]

◆ COMMAND_HANDLER() [10/10]

◆ is_gpio_valid()

◆ open_write_close()

◆ setup_sysfs_gpio()

◆ sysfsgpio_init()

◆ sysfsgpio_jtag_mode_possible()

◆ sysfsgpio_quit()

◆ sysfsgpio_read()

◆ sysfsgpio_reset()

◆ sysfsgpio_swd_mode_possible()

◆ sysfsgpio_swd_write()

◆ sysfsgpio_swdio_drive()

◆ sysfsgpio_swdio_read()

◆ sysfsgpio_write()

◆ unexport_sysfs_gpio()

Variable Documentation

◆ last_stored

◆ last_swclk

◆ last_swdio

◆ srst_fd

◆ srst_gpio

◆ swclk_fd

◆ swclk_gpio

◆ swdio_fd

◆ swdio_gpio

◆ swdio_input

◆ sysfsgpio_adapter_driver

◆ sysfsgpio_bitbang

◆ sysfsgpio_command_handlers

◆ sysfsgpio_interface

◆ sysfsgpio_subcommand_handlers

◆ sysfsgpio_transports

◆ tck_fd

◆ tck_gpio

◆ tdi_fd

◆ tdi_gpio

◆ tdo_fd

◆ tdo_gpio

◆ tms_fd

◆ tms_gpio

◆ trst_fd

◆ trst_gpio