1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * Bitbang driver for Linux GPIO descriptors through libgpiod
4 * Copyright (C) 2020 Antonio Borneo <borneo.antonio@gmail.com>
6 * Largely based on sysfsgpio driver
7 * Copyright (C) 2012 by Creative Product Design, marc @ cpdesign.com.au
8 * Copyright (C) 2014 by Jean-Christian de Rivaz <jc@eclis.ch>
9 * Copyright (C) 2014 by Paul Fertser <fercerpav@gmail.com>
17 #include <jtag/interface.h>
18 #include <transport/transport.h>
21 /* gpio numbers for each gpio. Negative values are invalid */
22 static int tck_gpio
= -1;
23 static int tms_gpio
= -1;
24 static int tdi_gpio
= -1;
25 static int tdo_gpio
= -1;
26 static int trst_gpio
= -1;
27 static int srst_gpio
= -1;
28 static int swclk_gpio
= -1;
29 static int swdio_gpio
= -1;
30 static int led_gpio
= -1;
31 static int gpiochip
= -1;
33 static struct gpiod_chip
*gpiod_chip
;
34 static struct gpiod_line
*gpiod_tck
;
35 static struct gpiod_line
*gpiod_tms
;
36 static struct gpiod_line
*gpiod_tdi
;
37 static struct gpiod_line
*gpiod_tdo
;
38 static struct gpiod_line
*gpiod_trst
;
39 static struct gpiod_line
*gpiod_swclk
;
40 static struct gpiod_line
*gpiod_swdio
;
41 static struct gpiod_line
*gpiod_srst
;
42 static struct gpiod_line
*gpiod_led
;
44 static int last_swclk
;
45 static int last_swdio
;
46 static bool last_stored
;
47 static bool swdio_input
;
49 /* Bitbang interface read of TDO */
50 static bb_value_t
linuxgpiod_read(void)
54 retval
= gpiod_line_get_value(gpiod_tdo
);
56 LOG_WARNING("reading tdo failed");
60 return retval
? BB_HIGH
: BB_LOW
;
64 * Bitbang interface write of TCK, TMS, TDI
66 * Seeing as this is the only function where the outputs are changed,
67 * we can cache the old value to avoid needlessly writing it.
69 static int linuxgpiod_write(int tck
, int tms
, int tdi
)
75 static int first_time
;
86 if (tdi
!= last_tdi
) {
87 retval
= gpiod_line_set_value(gpiod_tdi
, tdi
);
89 LOG_WARNING("writing tdi failed");
92 if (tms
!= last_tms
) {
93 retval
= gpiod_line_set_value(gpiod_tms
, tms
);
95 LOG_WARNING("writing tms failed");
99 if (tck
!= last_tck
) {
100 retval
= gpiod_line_set_value(gpiod_tck
, tck
);
102 LOG_WARNING("writing tck failed");
112 static int linuxgpiod_swdio_read(void)
116 retval
= gpiod_line_get_value(gpiod_swdio
);
118 LOG_WARNING("Fail read swdio");
125 static void linuxgpiod_swdio_drive(bool is_output
)
130 * FIXME: change direction requires release and re-require the line
131 * https://stackoverflow.com/questions/58735140/
132 * this would change in future libgpiod
134 gpiod_line_release(gpiod_swdio
);
137 retval
= gpiod_line_request_output(gpiod_swdio
, "OpenOCD", 1);
139 LOG_WARNING("Fail request_output line swdio");
141 retval
= gpiod_line_request_input(gpiod_swdio
, "OpenOCD");
143 LOG_WARNING("Fail request_input line swdio");
147 swdio_input
= !is_output
;
150 static int linuxgpiod_swd_write(int swclk
, int swdio
)
155 if (!last_stored
|| (swdio
!= last_swdio
)) {
156 retval
= gpiod_line_set_value(gpiod_swdio
, swdio
);
158 LOG_WARNING("Fail set swdio");
162 /* write swclk last */
163 if (!last_stored
|| (swclk
!= last_swclk
)) {
164 retval
= gpiod_line_set_value(gpiod_swclk
, swclk
);
166 LOG_WARNING("Fail set swclk");
176 static int linuxgpiod_blink(int on
)
183 retval
= gpiod_line_set_value(gpiod_led
, on
);
185 LOG_WARNING("Fail set led");
189 static struct bitbang_interface linuxgpiod_bitbang
= {
190 .read
= linuxgpiod_read
,
191 .write
= linuxgpiod_write
,
192 .swdio_read
= linuxgpiod_swdio_read
,
193 .swdio_drive
= linuxgpiod_swdio_drive
,
194 .swd_write
= linuxgpiod_swd_write
,
195 .blink
= linuxgpiod_blink
,
199 * Bitbang interface to manipulate reset lines SRST and TRST
201 * (1) assert or (0) deassert reset lines
203 static int linuxgpiod_reset(int trst
, int srst
)
205 int retval1
= 0, retval2
= 0;
207 LOG_DEBUG("linuxgpiod_reset");
209 /* assume active low */
211 retval1
= gpiod_line_set_value(gpiod_srst
, srst
? 0 : 1);
213 LOG_WARNING("set srst value failed");
216 /* assume active low */
218 retval2
= gpiod_line_set_value(gpiod_trst
, trst
? 0 : 1);
220 LOG_WARNING("set trst value failed");
223 return ((retval1
< 0) || (retval2
< 0)) ? ERROR_FAIL
: ERROR_OK
;
227 * Helper function to determine if gpio number is valid
229 * Assume here that there will be less than 10000 gpios per gpiochip
231 static bool is_gpio_valid(int gpio
)
233 return gpio
>= 0 && gpio
< 10000;
236 static bool linuxgpiod_jtag_mode_possible(void)
238 if (!is_gpio_valid(tck_gpio
))
240 if (!is_gpio_valid(tms_gpio
))
242 if (!is_gpio_valid(tdi_gpio
))
244 if (!is_gpio_valid(tdo_gpio
))
249 static bool linuxgpiod_swd_mode_possible(void)
251 if (!is_gpio_valid(swclk_gpio
))
253 if (!is_gpio_valid(swdio_gpio
))
258 static inline void helper_release(struct gpiod_line
*line
)
261 gpiod_line_release(line
);
264 static int linuxgpiod_quit(void)
266 helper_release(gpiod_led
);
267 helper_release(gpiod_srst
);
268 helper_release(gpiod_swdio
);
269 helper_release(gpiod_swclk
);
270 helper_release(gpiod_trst
);
271 helper_release(gpiod_tms
);
272 helper_release(gpiod_tck
);
273 helper_release(gpiod_tdi
);
274 helper_release(gpiod_tdo
);
276 gpiod_chip_close(gpiod_chip
);
281 static struct gpiod_line
*helper_get_input_line(const char *label
, unsigned int offset
)
283 struct gpiod_line
*line
;
286 line
= gpiod_chip_get_line(gpiod_chip
, offset
);
288 LOG_ERROR("Error get line %s", label
);
292 retval
= gpiod_line_request_input(line
, "OpenOCD");
294 LOG_ERROR("Error request_input line %s", label
);
301 static struct gpiod_line
*helper_get_output_line(const char *label
, unsigned int offset
, int val
)
303 struct gpiod_line
*line
;
306 line
= gpiod_chip_get_line(gpiod_chip
, offset
);
308 LOG_ERROR("Error get line %s", label
);
312 retval
= gpiod_line_request_output(line
, "OpenOCD", val
);
314 LOG_ERROR("Error request_output line %s", label
);
321 static int linuxgpiod_init(void)
323 LOG_INFO("Linux GPIOD JTAG/SWD bitbang driver");
325 bitbang_interface
= &linuxgpiod_bitbang
;
327 gpiod_chip
= gpiod_chip_open_by_number(gpiochip
);
329 LOG_ERROR("Cannot open LinuxGPIOD gpiochip %d", gpiochip
);
330 return ERROR_JTAG_INIT_FAILED
;
334 * Configure TDO as an input, and TDI, TCK, TMS, TRST, SRST
335 * as outputs. Drive TDI and TCK low, and TMS/TRST/SRST high.
336 * For SWD, SWCLK and SWDIO are configures as output high.
339 if (transport_is_jtag()) {
340 if (!linuxgpiod_jtag_mode_possible()) {
341 LOG_ERROR("Require tck, tms, tdi and tdo gpios for JTAG mode");
345 gpiod_tdo
= helper_get_input_line("tdo", tdo_gpio
);
349 gpiod_tdi
= helper_get_output_line("tdi", tdi_gpio
, 0);
353 gpiod_tck
= helper_get_output_line("tck", tck_gpio
, 0);
357 gpiod_tms
= helper_get_output_line("tms", tms_gpio
, 1);
361 if (is_gpio_valid(trst_gpio
)) {
362 gpiod_trst
= helper_get_output_line("trst", trst_gpio
, 1);
368 if (transport_is_swd()) {
369 if (!linuxgpiod_swd_mode_possible()) {
370 LOG_ERROR("Require swclk and swdio gpio for SWD mode");
374 gpiod_swclk
= helper_get_output_line("swclk", swclk_gpio
, 1);
378 gpiod_swdio
= helper_get_output_line("swdio", swdio_gpio
, 1);
383 if (is_gpio_valid(srst_gpio
)) {
384 gpiod_srst
= helper_get_output_line("srst", srst_gpio
, 1);
389 if (is_gpio_valid(led_gpio
)) {
390 gpiod_led
= helper_get_output_line("led", led_gpio
, 0);
400 return ERROR_JTAG_INIT_FAILED
;
403 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionums
)
406 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], tck_gpio
);
407 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[1], tms_gpio
);
408 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[2], tdi_gpio
);
409 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[3], tdo_gpio
);
410 } else if (CMD_ARGC
!= 0) {
411 return ERROR_COMMAND_SYNTAX_ERROR
;
415 "LinuxGPIOD nums: tck = %d, tms = %d, tdi = %d, tdo = %d",
416 tck_gpio
, tms_gpio
, tdi_gpio
, tdo_gpio
);
421 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tck
)
424 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], tck_gpio
);
426 command_print(CMD
, "LinuxGPIOD num: tck = %d", tck_gpio
);
430 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tms
)
433 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], tms_gpio
);
435 command_print(CMD
, "LinuxGPIOD num: tms = %d", tms_gpio
);
439 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tdo
)
442 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], tdo_gpio
);
444 command_print(CMD
, "LinuxGPIOD num: tdo = %d", tdo_gpio
);
448 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tdi
)
451 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], tdi_gpio
);
453 command_print(CMD
, "LinuxGPIOD num: tdi = %d", tdi_gpio
);
457 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_srst
)
460 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], srst_gpio
);
462 command_print(CMD
, "LinuxGPIOD num: srst = %d", srst_gpio
);
466 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_trst
)
469 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], trst_gpio
);
471 command_print(CMD
, "LinuxGPIOD num: trst = %d", trst_gpio
);
475 COMMAND_HANDLER(linuxgpiod_handle_swd_gpionums
)
478 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], swclk_gpio
);
479 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[1], swdio_gpio
);
480 } else if (CMD_ARGC
!= 0) {
481 return ERROR_COMMAND_SYNTAX_ERROR
;
485 "LinuxGPIOD nums: swclk = %d, swdio = %d",
486 swclk_gpio
, swdio_gpio
);
491 COMMAND_HANDLER(linuxgpiod_handle_swd_gpionum_swclk
)
494 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], swclk_gpio
);
496 command_print(CMD
, "LinuxGPIOD num: swclk = %d", swclk_gpio
);
500 COMMAND_HANDLER(linuxgpiod_handle_swd_gpionum_swdio
)
503 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], swdio_gpio
);
505 command_print(CMD
, "LinuxGPIOD num: swdio = %d", swdio_gpio
);
509 COMMAND_HANDLER(linuxgpiod_handle_gpionum_led
)
512 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], led_gpio
);
514 command_print(CMD
, "LinuxGPIOD num: led = %d", led_gpio
);
518 COMMAND_HANDLER(linuxgpiod_handle_gpiochip
)
521 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], gpiochip
);
523 command_print(CMD
, "LinuxGPIOD gpiochip = %d", gpiochip
);
527 static const struct command_registration linuxgpiod_subcommand_handlers
[] = {
530 .handler
= linuxgpiod_handle_jtag_gpionums
,
531 .mode
= COMMAND_CONFIG
,
532 .help
= "gpio numbers for tck, tms, tdi, tdo. (in that order)",
533 .usage
= "tck tms tdi tdo",
537 .handler
= linuxgpiod_handle_jtag_gpionum_tck
,
538 .mode
= COMMAND_CONFIG
,
539 .help
= "gpio number for tck.",
544 .handler
= linuxgpiod_handle_jtag_gpionum_tms
,
545 .mode
= COMMAND_CONFIG
,
546 .help
= "gpio number for tms.",
551 .handler
= linuxgpiod_handle_jtag_gpionum_tdo
,
552 .mode
= COMMAND_CONFIG
,
553 .help
= "gpio number for tdo.",
558 .handler
= linuxgpiod_handle_jtag_gpionum_tdi
,
559 .mode
= COMMAND_CONFIG
,
560 .help
= "gpio number for tdi.",
565 .handler
= linuxgpiod_handle_jtag_gpionum_srst
,
566 .mode
= COMMAND_CONFIG
,
567 .help
= "gpio number for srst.",
572 .handler
= linuxgpiod_handle_jtag_gpionum_trst
,
573 .mode
= COMMAND_CONFIG
,
574 .help
= "gpio number for trst.",
579 .handler
= linuxgpiod_handle_swd_gpionums
,
580 .mode
= COMMAND_CONFIG
,
581 .help
= "gpio numbers for swclk, swdio. (in that order)",
582 .usage
= "swclk swdio",
586 .handler
= linuxgpiod_handle_swd_gpionum_swclk
,
587 .mode
= COMMAND_CONFIG
,
588 .help
= "gpio number for swclk.",
593 .handler
= linuxgpiod_handle_swd_gpionum_swdio
,
594 .mode
= COMMAND_CONFIG
,
595 .help
= "gpio number for swdio.",
600 .handler
= linuxgpiod_handle_gpionum_led
,
601 .mode
= COMMAND_CONFIG
,
602 .help
= "gpio number for LED.",
607 .handler
= linuxgpiod_handle_gpiochip
,
608 .mode
= COMMAND_CONFIG
,
609 .help
= "number of the gpiochip.",
612 COMMAND_REGISTRATION_DONE
615 static const struct command_registration linuxgpiod_command_handlers
[] = {
617 .name
= "linuxgpiod",
619 .help
= "perform linuxgpiod management",
620 .chain
= linuxgpiod_subcommand_handlers
,
623 COMMAND_REGISTRATION_DONE
626 static const char *const linuxgpiod_transport
[] = { "swd", "jtag", NULL
};
628 static struct jtag_interface linuxgpiod_interface
= {
629 .supported
= DEBUG_CAP_TMS_SEQ
,
630 .execute_queue
= bitbang_execute_queue
,
633 struct adapter_driver linuxgpiod_adapter_driver
= {
634 .name
= "linuxgpiod",
635 .transports
= linuxgpiod_transport
,
636 .commands
= linuxgpiod_command_handlers
,
638 .init
= linuxgpiod_init
,
639 .quit
= linuxgpiod_quit
,
640 .reset
= linuxgpiod_reset
,
642 .jtag_ops
= &linuxgpiod_interface
,
643 .swd_ops
= &bitbang_swd
,
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