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 gpiochip
= -1;
32 static struct gpiod_chip
*gpiod_chip
;
33 static struct gpiod_line
*gpiod_tck
;
34 static struct gpiod_line
*gpiod_tms
;
35 static struct gpiod_line
*gpiod_tdi
;
36 static struct gpiod_line
*gpiod_tdo
;
37 static struct gpiod_line
*gpiod_trst
;
38 static struct gpiod_line
*gpiod_swclk
;
39 static struct gpiod_line
*gpiod_swdio
;
40 static struct gpiod_line
*gpiod_srst
;
42 static int last_swclk
;
43 static int last_swdio
;
44 static bool last_stored
;
45 static bool swdio_input
;
47 /* Bitbang interface read of TDO */
48 static bb_value_t
linuxgpiod_read(void)
52 retval
= gpiod_line_get_value(gpiod_tdo
);
54 LOG_WARNING("reading tdo failed");
58 return retval
? BB_HIGH
: BB_LOW
;
62 * Bitbang interface write of TCK, TMS, TDI
64 * Seeing as this is the only function where the outputs are changed,
65 * we can cache the old value to avoid needlessly writing it.
67 static int linuxgpiod_write(int tck
, int tms
, int tdi
)
73 static int first_time
;
84 if (tdi
!= last_tdi
) {
85 retval
= gpiod_line_set_value(gpiod_tdi
, tdi
);
87 LOG_WARNING("writing tdi failed");
90 if (tms
!= last_tms
) {
91 retval
= gpiod_line_set_value(gpiod_tms
, tms
);
93 LOG_WARNING("writing tms failed");
97 if (tck
!= last_tck
) {
98 retval
= gpiod_line_set_value(gpiod_tck
, tck
);
100 LOG_WARNING("writing tck failed");
110 static int linuxgpiod_swdio_read(void)
114 retval
= gpiod_line_get_value(gpiod_swdio
);
116 LOG_WARNING("Fail read swdio");
123 static void linuxgpiod_swdio_drive(bool is_output
)
128 * FIXME: change direction requires release and re-require the line
129 * https://stackoverflow.com/questions/58735140/
130 * this would change in future libgpiod
132 gpiod_line_release(gpiod_swdio
);
135 retval
= gpiod_line_request_output(gpiod_swdio
, "OpenOCD", 1);
137 LOG_WARNING("Fail request_output line swdio");
139 retval
= gpiod_line_request_input(gpiod_swdio
, "OpenOCD");
141 LOG_WARNING("Fail request_input line swdio");
145 swdio_input
= !is_output
;
148 static int linuxgpiod_swd_write(int swclk
, int swdio
)
153 if (!last_stored
|| (swdio
!= last_swdio
)) {
154 retval
= gpiod_line_set_value(gpiod_swdio
, swdio
);
156 LOG_WARNING("Fail set swdio");
160 /* write swclk last */
161 if (!last_stored
|| (swclk
!= last_swclk
)) {
162 retval
= gpiod_line_set_value(gpiod_swclk
, swclk
);
164 LOG_WARNING("Fail set swclk");
174 static struct bitbang_interface linuxgpiod_bitbang
= {
175 .read
= linuxgpiod_read
,
176 .write
= linuxgpiod_write
,
177 .swdio_read
= linuxgpiod_swdio_read
,
178 .swdio_drive
= linuxgpiod_swdio_drive
,
179 .swd_write
= linuxgpiod_swd_write
,
184 * Bitbang interface to manipulate reset lines SRST and TRST
186 * (1) assert or (0) deassert reset lines
188 static int linuxgpiod_reset(int trst
, int srst
)
190 int retval1
= 0, retval2
= 0;
192 LOG_DEBUG("linuxgpiod_reset");
194 /* assume active low */
195 if (gpiod_srst
!= NULL
) {
196 retval1
= gpiod_line_set_value(gpiod_srst
, srst
? 0 : 1);
198 LOG_WARNING("set srst value failed");
201 /* assume active low */
202 if (gpiod_trst
!= NULL
) {
203 retval2
= gpiod_line_set_value(gpiod_trst
, trst
? 0 : 1);
205 LOG_WARNING("set trst value failed");
208 return ((retval1
< 0) || (retval2
< 0)) ? ERROR_FAIL
: ERROR_OK
;
212 * Helper function to determine if gpio number is valid
214 * Assume here that there will be less than 10000 gpios per gpiochip
216 static bool is_gpio_valid(int gpio
)
218 return gpio
>= 0 && gpio
< 10000;
221 static bool linuxgpiod_jtag_mode_possible(void)
223 if (!is_gpio_valid(tck_gpio
))
225 if (!is_gpio_valid(tms_gpio
))
227 if (!is_gpio_valid(tdi_gpio
))
229 if (!is_gpio_valid(tdo_gpio
))
234 static bool linuxgpiod_swd_mode_possible(void)
236 if (!is_gpio_valid(swclk_gpio
))
238 if (!is_gpio_valid(swdio_gpio
))
243 static inline void helper_release(struct gpiod_line
*line
)
246 gpiod_line_release(line
);
249 static int linuxgpiod_quit(void)
251 helper_release(gpiod_srst
);
252 helper_release(gpiod_swdio
);
253 helper_release(gpiod_swclk
);
254 helper_release(gpiod_trst
);
255 helper_release(gpiod_tms
);
256 helper_release(gpiod_tck
);
257 helper_release(gpiod_tdi
);
258 helper_release(gpiod_tdo
);
260 gpiod_chip_close(gpiod_chip
);
265 static struct gpiod_line
*helper_get_input_line(const char *label
, unsigned int offset
)
267 struct gpiod_line
*line
;
270 line
= gpiod_chip_get_line(gpiod_chip
, offset
);
272 LOG_ERROR("Error get line %s", label
);
276 retval
= gpiod_line_request_input(line
, "OpenOCD");
278 LOG_ERROR("Error request_input line %s", label
);
285 static struct gpiod_line
*helper_get_output_line(const char *label
, unsigned int offset
, int val
)
287 struct gpiod_line
*line
;
290 line
= gpiod_chip_get_line(gpiod_chip
, offset
);
292 LOG_ERROR("Error get line %s", label
);
296 retval
= gpiod_line_request_output(line
, "OpenOCD", val
);
298 LOG_ERROR("Error request_output line %s", label
);
305 static int linuxgpiod_init(void)
307 LOG_INFO("Linux GPIOD JTAG/SWD bitbang driver");
309 bitbang_interface
= &linuxgpiod_bitbang
;
311 gpiod_chip
= gpiod_chip_open_by_number(gpiochip
);
312 if (gpiod_chip
== NULL
) {
313 LOG_ERROR("Cannot open LinuxGPIOD gpiochip %d", gpiochip
);
314 return ERROR_JTAG_INIT_FAILED
;
318 * Configure TDO as an input, and TDI, TCK, TMS, TRST, SRST
319 * as outputs. Drive TDI and TCK low, and TMS/TRST/SRST high.
320 * For SWD, SWCLK and SWDIO are configures as output high.
323 if (transport_is_jtag()) {
324 if (!linuxgpiod_jtag_mode_possible()) {
325 LOG_ERROR("Require tck, tms, tdi and tdo gpios for JTAG mode");
329 gpiod_tdo
= helper_get_input_line("tdo", tdo_gpio
);
330 if (gpiod_tdo
== NULL
)
333 gpiod_tdi
= helper_get_output_line("tdi", tdi_gpio
, 0);
334 if (gpiod_tdi
== NULL
)
337 gpiod_tck
= helper_get_output_line("tck", tck_gpio
, 0);
338 if (gpiod_tck
== NULL
)
341 gpiod_tms
= helper_get_output_line("tms", tms_gpio
, 1);
342 if (gpiod_tms
== NULL
)
345 if (is_gpio_valid(trst_gpio
)) {
346 gpiod_trst
= helper_get_output_line("trst", trst_gpio
, 1);
347 if (gpiod_trst
== NULL
)
352 if (transport_is_swd()) {
353 if (!linuxgpiod_swd_mode_possible()) {
354 LOG_ERROR("Require swclk and swdio gpio for SWD mode");
358 gpiod_swclk
= helper_get_output_line("swclk", swclk_gpio
, 1);
359 if (gpiod_swclk
== NULL
)
362 gpiod_swdio
= helper_get_output_line("swdio", swdio_gpio
, 1);
363 if (gpiod_swdio
== NULL
)
367 if (is_gpio_valid(srst_gpio
)) {
368 gpiod_srst
= helper_get_output_line("srst", srst_gpio
, 1);
369 if (gpiod_srst
== NULL
)
378 return ERROR_JTAG_INIT_FAILED
;
381 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionums
)
384 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], tck_gpio
);
385 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[1], tms_gpio
);
386 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[2], tdi_gpio
);
387 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[3], tdo_gpio
);
388 } else if (CMD_ARGC
!= 0) {
389 return ERROR_COMMAND_SYNTAX_ERROR
;
393 "LinuxGPIOD nums: tck = %d, tms = %d, tdi = %d, tdo = %d",
394 tck_gpio
, tms_gpio
, tdi_gpio
, tdo_gpio
);
399 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tck
)
402 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], tck_gpio
);
404 command_print(CMD
, "LinuxGPIOD num: tck = %d", tck_gpio
);
408 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tms
)
411 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], tms_gpio
);
413 command_print(CMD
, "LinuxGPIOD num: tms = %d", tms_gpio
);
417 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tdo
)
420 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], tdo_gpio
);
422 command_print(CMD
, "LinuxGPIOD num: tdo = %d", tdo_gpio
);
426 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tdi
)
429 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], tdi_gpio
);
431 command_print(CMD
, "LinuxGPIOD num: tdi = %d", tdi_gpio
);
435 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_srst
)
438 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], srst_gpio
);
440 command_print(CMD
, "LinuxGPIOD num: srst = %d", srst_gpio
);
444 COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_trst
)
447 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], trst_gpio
);
449 command_print(CMD
, "LinuxGPIOD num: trst = %d", trst_gpio
);
453 COMMAND_HANDLER(linuxgpiod_handle_swd_gpionums
)
456 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], swclk_gpio
);
457 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[1], swdio_gpio
);
458 } else if (CMD_ARGC
!= 0) {
459 return ERROR_COMMAND_SYNTAX_ERROR
;
463 "LinuxGPIOD nums: swclk = %d, swdio = %d",
464 swclk_gpio
, swdio_gpio
);
469 COMMAND_HANDLER(linuxgpiod_handle_swd_gpionum_swclk
)
472 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], swclk_gpio
);
474 command_print(CMD
, "LinuxGPIOD num: swclk = %d", swclk_gpio
);
478 COMMAND_HANDLER(linuxgpiod_handle_swd_gpionum_swdio
)
481 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], swdio_gpio
);
483 command_print(CMD
, "LinuxGPIOD num: swdio = %d", swdio_gpio
);
487 COMMAND_HANDLER(linuxgpiod_handle_gpiochip
)
490 COMMAND_PARSE_NUMBER(int, CMD_ARGV
[0], gpiochip
);
492 command_print(CMD
, "LinuxGPIOD gpiochip = %d", gpiochip
);
496 static const struct command_registration linuxgpiod_command_handlers
[] = {
498 .name
= "linuxgpiod_jtag_nums",
499 .handler
= linuxgpiod_handle_jtag_gpionums
,
500 .mode
= COMMAND_CONFIG
,
501 .help
= "gpio numbers for tck, tms, tdi, tdo. (in that order)",
502 .usage
= "tck tms tdi tdo",
505 .name
= "linuxgpiod_tck_num",
506 .handler
= linuxgpiod_handle_jtag_gpionum_tck
,
507 .mode
= COMMAND_CONFIG
,
508 .help
= "gpio number for tck.",
512 .name
= "linuxgpiod_tms_num",
513 .handler
= linuxgpiod_handle_jtag_gpionum_tms
,
514 .mode
= COMMAND_CONFIG
,
515 .help
= "gpio number for tms.",
519 .name
= "linuxgpiod_tdo_num",
520 .handler
= linuxgpiod_handle_jtag_gpionum_tdo
,
521 .mode
= COMMAND_CONFIG
,
522 .help
= "gpio number for tdo.",
526 .name
= "linuxgpiod_tdi_num",
527 .handler
= linuxgpiod_handle_jtag_gpionum_tdi
,
528 .mode
= COMMAND_CONFIG
,
529 .help
= "gpio number for tdi.",
533 .name
= "linuxgpiod_srst_num",
534 .handler
= linuxgpiod_handle_jtag_gpionum_srst
,
535 .mode
= COMMAND_CONFIG
,
536 .help
= "gpio number for srst.",
540 .name
= "linuxgpiod_trst_num",
541 .handler
= linuxgpiod_handle_jtag_gpionum_trst
,
542 .mode
= COMMAND_CONFIG
,
543 .help
= "gpio number for trst.",
547 .name
= "linuxgpiod_swd_nums",
548 .handler
= linuxgpiod_handle_swd_gpionums
,
549 .mode
= COMMAND_CONFIG
,
550 .help
= "gpio numbers for swclk, swdio. (in that order)",
551 .usage
= "swclk swdio",
554 .name
= "linuxgpiod_swclk_num",
555 .handler
= linuxgpiod_handle_swd_gpionum_swclk
,
556 .mode
= COMMAND_CONFIG
,
557 .help
= "gpio number for swclk.",
561 .name
= "linuxgpiod_swdio_num",
562 .handler
= linuxgpiod_handle_swd_gpionum_swdio
,
563 .mode
= COMMAND_CONFIG
,
564 .help
= "gpio number for swdio.",
568 .name
= "linuxgpiod_gpiochip",
569 .handler
= linuxgpiod_handle_gpiochip
,
570 .mode
= COMMAND_CONFIG
,
571 .help
= "number of the gpiochip.",
574 COMMAND_REGISTRATION_DONE
577 static const char *const linuxgpiod_transport
[] = { "swd", "jtag", NULL
};
579 static struct jtag_interface linuxgpiod_interface
= {
580 .supported
= DEBUG_CAP_TMS_SEQ
,
581 .execute_queue
= bitbang_execute_queue
,
584 struct adapter_driver linuxgpiod_adapter_driver
= {
585 .name
= "linuxgpiod",
586 .transports
= linuxgpiod_transport
,
587 .commands
= linuxgpiod_command_handlers
,
589 .init
= linuxgpiod_init
,
590 .quit
= linuxgpiod_quit
,
591 .reset
= linuxgpiod_reset
,
593 .jtag_ops
= &linuxgpiod_interface
,
594 .swd_ops
= &bitbang_swd
,
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