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/adapter.h>
18 #include <jtag/interface.h>
19 #include <transport/transport.h>
22 static struct gpiod_chip *gpiod_chip[ADAPTER_GPIO_IDX_NUM] = {};
23 static struct gpiod_line *gpiod_line[ADAPTER_GPIO_IDX_NUM] = {};
25 static int last_swclk;
26 static int last_swdio;
27 static bool last_stored;
28 static bool swdio_input;
30 static const struct adapter_gpio_config *adapter_gpio_config;
33 * Helper function to determine if gpio config is valid
35 * Assume here that there will be less than 10000 gpios per gpiochip, and less
36 * than 1000 gpiochips.
38 static bool is_gpio_config_valid(enum adapter_gpio_config_index idx)
40 return adapter_gpio_config[idx].chip_num >= 0
41 && adapter_gpio_config[idx].chip_num < 1000
42 && adapter_gpio_config[idx].gpio_num >= 0
43 && adapter_gpio_config[idx].gpio_num < 10000;
46 /* Bitbang interface read of TDO */
47 static bb_value_t linuxgpiod_read(void)
51 retval = gpiod_line_get_value(gpiod_line[ADAPTER_GPIO_IDX_TDO]);
53 LOG_WARNING("reading tdo failed");
57 return retval ? BB_HIGH : BB_LOW;
61 * Bitbang interface write of TCK, TMS, TDI
63 * Seeing as this is the only function where the outputs are changed,
64 * we can cache the old value to avoid needlessly writing it.
66 static int linuxgpiod_write(int tck, int tms, int tdi)
72 static int first_time;
83 if (tdi != last_tdi) {
84 retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_TDI], tdi);
86 LOG_WARNING("writing tdi failed");
89 if (tms != last_tms) {
90 retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_TMS], tms);
92 LOG_WARNING("writing tms failed");
96 if (tck != last_tck) {
97 retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_TCK], tck);
99 LOG_WARNING("writing tck failed");
109 static int linuxgpiod_swdio_read(void)
113 retval = gpiod_line_get_value(gpiod_line[ADAPTER_GPIO_IDX_SWDIO]);
115 LOG_WARNING("Fail read swdio");
122 static void linuxgpiod_swdio_drive(bool is_output)
127 * FIXME: change direction requires release and re-require the line
128 * https://stackoverflow.com/questions/58735140/
129 * this would change in future libgpiod
131 gpiod_line_release(gpiod_line[ADAPTER_GPIO_IDX_SWDIO]);
134 if (gpiod_line[ADAPTER_GPIO_IDX_SWDIO_DIR]) {
135 retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_SWDIO_DIR], 1);
137 LOG_WARNING("Fail set swdio_dir");
139 retval = gpiod_line_request_output(gpiod_line[ADAPTER_GPIO_IDX_SWDIO], "OpenOCD", 1);
141 LOG_WARNING("Fail request_output line swdio");
143 retval = gpiod_line_request_input(gpiod_line[ADAPTER_GPIO_IDX_SWDIO], "OpenOCD");
145 LOG_WARNING("Fail request_input line swdio");
146 if (gpiod_line[ADAPTER_GPIO_IDX_SWDIO_DIR]) {
147 retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_SWDIO_DIR], 0);
149 LOG_WARNING("Fail set swdio_dir");
154 swdio_input = !is_output;
157 static int linuxgpiod_swd_write(int swclk, int swdio)
162 if (!last_stored || (swdio != last_swdio)) {
163 retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_SWDIO], swdio);
165 LOG_WARNING("Fail set swdio");
169 /* write swclk last */
170 if (!last_stored || (swclk != last_swclk)) {
171 retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_SWCLK], swclk);
173 LOG_WARNING("Fail set swclk");
183 static int linuxgpiod_blink(int on)
187 if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_LED))
190 retval = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_LED], on);
192 LOG_WARNING("Fail set led");
196 static struct bitbang_interface linuxgpiod_bitbang = {
197 .read = linuxgpiod_read,
198 .write = linuxgpiod_write,
199 .swdio_read = linuxgpiod_swdio_read,
200 .swdio_drive = linuxgpiod_swdio_drive,
201 .swd_write = linuxgpiod_swd_write,
202 .blink = linuxgpiod_blink,
206 * Bitbang interface to manipulate reset lines SRST and TRST
208 * (1) assert or (0) deassert reset lines
210 static int linuxgpiod_reset(int trst, int srst)
212 int retval1 = 0, retval2 = 0;
214 LOG_DEBUG("linuxgpiod_reset");
217 * active low behaviour handled by "adaptor gpio" command and
218 * GPIOD_LINE_REQUEST_FLAG_ACTIVE_LOW flag when requesting the line.
220 if (gpiod_line[ADAPTER_GPIO_IDX_SRST]) {
221 retval1 = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_SRST], srst);
223 LOG_WARNING("set srst value failed");
226 if (gpiod_line[ADAPTER_GPIO_IDX_TRST]) {
227 retval2 = gpiod_line_set_value(gpiod_line[ADAPTER_GPIO_IDX_TRST], trst);
229 LOG_WARNING("set trst value failed");
232 return ((retval1 < 0) || (retval2 < 0)) ? ERROR_FAIL : ERROR_OK;
235 static bool linuxgpiod_jtag_mode_possible(void)
237 if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_TCK))
239 if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_TMS))
241 if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_TDI))
243 if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_TDO))
248 static bool linuxgpiod_swd_mode_possible(void)
250 if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_SWCLK))
252 if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_SWDIO))
257 static inline void helper_release(enum adapter_gpio_config_index idx)
259 if (gpiod_line[idx]) {
260 gpiod_line_release(gpiod_line[idx]);
261 gpiod_line[idx] = NULL;
263 if (gpiod_chip[idx]) {
264 gpiod_chip_close(gpiod_chip[idx]);
265 gpiod_chip[idx] = NULL;
269 static int linuxgpiod_quit(void)
271 LOG_DEBUG("linuxgpiod_quit");
272 for (int i = 0; i < ADAPTER_GPIO_IDX_NUM; ++i)
278 static int helper_get_line(enum adapter_gpio_config_index idx)
280 if (!is_gpio_config_valid(idx))
283 int dir = GPIOD_LINE_REQUEST_DIRECTION_INPUT, flags = 0, val = 0, retval;
285 gpiod_chip[idx] = gpiod_chip_open_by_number(adapter_gpio_config[idx].chip_num);
286 if (!gpiod_chip[idx]) {
287 LOG_ERROR("Cannot open LinuxGPIOD chip %d for %s", adapter_gpio_config[idx].chip_num,
288 adapter_gpio_get_name(idx));
289 return ERROR_JTAG_INIT_FAILED;
292 gpiod_line[idx] = gpiod_chip_get_line(gpiod_chip[idx], adapter_gpio_config[idx].gpio_num);
293 if (!gpiod_line[idx]) {
294 LOG_ERROR("Error get line %s", adapter_gpio_get_name(idx));
295 return ERROR_JTAG_INIT_FAILED;
298 switch (adapter_gpio_config[idx].init_state) {
299 case ADAPTER_GPIO_INIT_STATE_INPUT:
300 dir = GPIOD_LINE_REQUEST_DIRECTION_INPUT;
302 case ADAPTER_GPIO_INIT_STATE_INACTIVE:
303 dir = GPIOD_LINE_REQUEST_DIRECTION_OUTPUT;
306 case ADAPTER_GPIO_INIT_STATE_ACTIVE:
307 dir = GPIOD_LINE_REQUEST_DIRECTION_OUTPUT;
312 switch (adapter_gpio_config[idx].drive) {
313 case ADAPTER_GPIO_DRIVE_MODE_PUSH_PULL:
315 case ADAPTER_GPIO_DRIVE_MODE_OPEN_DRAIN:
316 flags |= GPIOD_LINE_REQUEST_FLAG_OPEN_DRAIN;
318 case ADAPTER_GPIO_DRIVE_MODE_OPEN_SOURCE:
319 flags |= GPIOD_LINE_REQUEST_FLAG_OPEN_SOURCE;
323 switch (adapter_gpio_config[idx].pull) {
324 case ADAPTER_GPIO_PULL_NONE:
325 #ifdef GPIOD_LINE_REQUEST_FLAG_BIAS_DISABLE
326 flags |= GPIOD_LINE_REQUEST_FLAG_BIAS_DISABLE;
329 case ADAPTER_GPIO_PULL_UP:
330 #ifdef GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_UP
331 flags |= GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_UP;
333 LOG_WARNING("linuxgpiod: ignoring request for pull-up on %s: not supported by gpiod v%s",
334 adapter_gpio_get_name(idx), gpiod_version_string());
337 case ADAPTER_GPIO_PULL_DOWN:
338 #ifdef GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_DOWN
339 flags |= GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_DOWN;
341 LOG_WARNING("linuxgpiod: ignoring request for pull-down on %s: not supported by gpiod v%s",
342 adapter_gpio_get_name(idx), gpiod_version_string());
347 if (adapter_gpio_config[idx].active_low)
348 flags |= GPIOD_LINE_REQUEST_FLAG_ACTIVE_LOW;
350 struct gpiod_line_request_config config = {
351 .consumer = "OpenOCD",
356 retval = gpiod_line_request(gpiod_line[idx], &config, val);
358 LOG_ERROR("Error requesting gpio line %s", adapter_gpio_get_name(idx));
359 return ERROR_JTAG_INIT_FAILED;
365 static int linuxgpiod_init(void)
367 LOG_INFO("Linux GPIOD JTAG/SWD bitbang driver");
369 bitbang_interface = &linuxgpiod_bitbang;
370 adapter_gpio_config = adapter_gpio_get_config();
373 * Configure JTAG/SWD signals. Default directions and initial states are handled
374 * by adapter.c and "adapter gpio" command.
377 if (transport_is_jtag()) {
378 if (!linuxgpiod_jtag_mode_possible()) {
379 LOG_ERROR("Require tck, tms, tdi and tdo gpios for JTAG mode");
383 if (helper_get_line(ADAPTER_GPIO_IDX_TDO) != ERROR_OK ||
384 helper_get_line(ADAPTER_GPIO_IDX_TDI) != ERROR_OK ||
385 helper_get_line(ADAPTER_GPIO_IDX_TCK) != ERROR_OK ||
386 helper_get_line(ADAPTER_GPIO_IDX_TMS) != ERROR_OK ||
387 helper_get_line(ADAPTER_GPIO_IDX_TRST) != ERROR_OK)
391 if (transport_is_swd()) {
392 int retval1, retval2;
393 if (!linuxgpiod_swd_mode_possible()) {
394 LOG_ERROR("Require swclk and swdio gpio for SWD mode");
399 * swdio and its buffer should be initialized in the order that prevents
400 * two outputs from being connected together. This will occur if the
401 * swdio GPIO is configured as an output while the external buffer is
402 * configured to send the swdio signal from the target to the GPIO.
404 if (adapter_gpio_config[ADAPTER_GPIO_IDX_SWDIO].init_state == ADAPTER_GPIO_INIT_STATE_INPUT) {
405 retval1 = helper_get_line(ADAPTER_GPIO_IDX_SWDIO);
406 retval2 = helper_get_line(ADAPTER_GPIO_IDX_SWDIO_DIR);
408 retval1 = helper_get_line(ADAPTER_GPIO_IDX_SWDIO_DIR);
409 retval2 = helper_get_line(ADAPTER_GPIO_IDX_SWDIO);
411 if (retval1 != ERROR_OK || retval2 != ERROR_OK)
414 if (helper_get_line(ADAPTER_GPIO_IDX_SWCLK) != ERROR_OK)
418 if (helper_get_line(ADAPTER_GPIO_IDX_SRST) != ERROR_OK ||
419 helper_get_line(ADAPTER_GPIO_IDX_LED) != ERROR_OK)
427 return ERROR_JTAG_INIT_FAILED;
430 static const char *const linuxgpiod_transport[] = { "swd", "jtag", NULL };
432 static struct jtag_interface linuxgpiod_interface = {
433 .supported = DEBUG_CAP_TMS_SEQ,
434 .execute_queue = bitbang_execute_queue,
437 struct adapter_driver linuxgpiod_adapter_driver = {
438 .name = "linuxgpiod",
439 .transports = linuxgpiod_transport,
441 .init = linuxgpiod_init,
442 .quit = linuxgpiod_quit,
443 .reset = linuxgpiod_reset,
445 .jtag_ops = &linuxgpiod_interface,
446 .swd_ops = &bitbang_swd,