// SPDX-License-Identifier: GPL-2.0-or-later
/***************************************************************************
+ * Copyright (C) 2021 by Manuel Wick <manuel@matronix.de> *
* Copyright (C) 2013 Paul Fertser <fercerpav@gmail.com> *
* Copyright (C) 2012 by Creative Product Design, marc @ cpdesign.com.au *
***************************************************************************/
/*
- This is a test application to be used as a remote bitbang server for
- the OpenOCD remote_bitbang interface driver.
-
- To compile run:
- gcc -Wall -ansi -pedantic -std=c99 -o remote_bitbang_sysfsgpio remote_bitbang_sysfsgpio.c
-
-
- Usage example:
-
- On Raspberry Pi run:
- socat TCP6-LISTEN:7777,fork EXEC:"sudo ./remote_bitbang_sysfsgpio tck 11 tms 25 tdo 9 tdi 10"
-
- On host run:
- openocd -c "interface remote_bitbang; remote_bitbang host raspberrypi; remote_bitbang port 7777" \
- -f target/stm32f1x.cfg
-
- Or if you want to test UNIX sockets, run both on Raspberry Pi:
- socat UNIX-LISTEN:/tmp/remotebitbang-socket,fork EXEC:"sudo ./remote_bitbang_sysfsgpio tck 11 tms 25 tdo 9 tdi 10"
- openocd -c "interface remote_bitbang; remote_bitbang host /tmp/remotebitbang-socket" -f target/stm32f1x.cfg
+ * This is a test application to be used as a remote bitbang server for
+ * the OpenOCD remote_bitbang interface driver.
+ *
+ * To compile run:
+ * gcc -Wall -ansi -pedantic -std=c99 -o remote_bitbang_sysfsgpio remote_bitbang_sysfsgpio.c
+ *
+ *
+ * Usage example:
+ *
+ * On Raspberry Pi run:
+ * socat TCP6-LISTEN:7777,fork EXEC:"sudo ./remote_bitbang_sysfsgpio tck 11 tms 25 tdo 9 tdi 10"
+ *
+ * On host run:
+ * openocd -c "adapter driver remote_bitbang; remote_bitbang host raspberrypi; remote_bitbang port 7777" \
+ * -f target/stm32f1x.cfg
+ *
+ * Or if you want to test UNIX sockets, run both on Raspberry Pi:
+ * socat UNIX-LISTEN:/tmp/remotebitbang-socket,fork EXEC:"sudo ./remote_bitbang_sysfsgpio tck 11 tms 25 tdo 9 tdi 10"
+ * openocd -c "adapter driver remote_bitbang; remote_bitbang host /tmp/remotebitbang-socket" -f target/stm32f1x.cfg
*/
#include <sys/types.h>
* If the gpio is an output, it is initialized according to init_high,
* otherwise it is ignored.
*
+ * When open_rw is set, the file descriptor will be open as read and write,
+ * e.g. for SWDIO (TMS) that is used as input and output.
+ *
* If the gpio is already exported we just show a warning and continue; if
* openocd happened to crash (or was killed by user) then the gpios will not
* have been cleaned up.
*/
-static int setup_sysfs_gpio(int gpio, int is_output, int init_high)
+static int setup_sysfs_gpio(int gpio, int is_output, int init_high, int open_rw)
{
char buf[40];
char gpiostr[4];
}
snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/value", gpio);
- if (is_output)
+ if (open_rw)
+ ret = open(buf, O_RDWR | O_NONBLOCK | O_SYNC);
+ else if (is_output)
ret = open(buf, O_WRONLY | O_NONBLOCK | O_SYNC);
else
ret = open(buf, O_RDONLY | O_NONBLOCK | O_SYNC);
return ret;
}
+/*
+ * Change direction for gpio.
+ */
+static int change_dir_sysfs_gpio(int gpio, int is_output, int init_high)
+{
+ char buf[40];
+ int ret;
+
+ if (!is_gpio_valid(gpio))
+ return ERROR_OK;
+
+ snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/direction", gpio);
+ ret = open_write_close(buf, is_output ? (init_high ? "high" : "low") : "in");
+ if (ret < 0) {
+ LOG_ERROR("Couldn't set direction for gpio %d", gpio);
+ perror("sysfsgpio: ");
+ unexport_sysfs_gpio(gpio);
+ return ERROR_FAIL;
+ }
+
+ return ERROR_OK;
+}
+
+/* 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;
+
/*
* file descriptors for /sys/class/gpio/gpioXX/value
* Set up during init.
static int trst_fd = -1;
static int srst_fd = -1;
+/*
+ * GPIO state of /sys/class/gpio/gpioXX/value
+ */
+static int last_tck = -1;
+static int last_tms = -1;
+static int last_tms_drive = -1;
+static int last_tdi = -1;
+static int last_initialized = -1;
+
/*
* Bitbang interface read of TDO
*
/*
* 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.
+ * Output states are changed here and in sysfsgpio_write_swd,
+ * which are not used simultaneously, so we can cache the old
+ * value to avoid needlessly writing it.
*/
static void sysfsgpio_write(int tck, int tms, int tdi)
{
const char one[] = "1";
const char zero[] = "0";
- static int last_tck;
- static int last_tms;
- static int last_tdi;
-
- static int first_time;
size_t bytes_written;
- if (!first_time) {
+ if (!last_initialized) {
last_tck = !tck;
last_tms = !tms;
last_tdi = !tdi;
- first_time = 1;
+ last_initialized = 1;
}
if (tdi != last_tdi) {
}
}
-/* 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;
+/*
+ * Bitbang interface set direction of SWDIO (TMS)
+ */
+static void sysfsgpio_swdio_drive(int is_output)
+{
+ int ret;
+
+ if (is_output != 0 && last_tms == -1)
+ last_tms = 0;
+
+ ret = change_dir_sysfs_gpio(tms_gpio, (is_output != 0) ? 1 : 0, last_tms);
+ if (ret != ERROR_OK)
+ LOG_WARNING("Failed to change SWDIO (TMS) direction to output");
+ else
+ last_tms_drive = (is_output != 0) ? 1 : 0;
+}
+
+/*
+ * Bitbang interface read of SWDIO (TMS)
+ *
+ * The sysfs value will read back either '0' or '1'. The trick here is to call
+ * lseek to bypass buffering in the sysfs kernel driver.
+ */
+static int sysfsgpio_swdio_read(void)
+{
+ char buf[1];
+
+ /* important to seek to signal sysfs of new read */
+ lseek(tms_fd, 0, SEEK_SET);
+ int ret = read(tms_fd, &buf, sizeof(buf));
+
+ if (ret < 0) {
+ LOG_WARNING("reading swdio (tms) failed");
+ return 0;
+ }
+
+ return buf[0];
+}
+
+/*
+ * Bitbang interface write of SWCLK (TCK) and SWDIO (TMS)
+ *
+ * Output states are changed here and in sysfsgpio_write, which
+ * are not used simultaneously, so we can cache the old value
+ * to avoid needlessly writing it.
+ */
+static void sysfsgpio_swd_write(int swclk, int swdio)
+{
+ static const char one[] = "1";
+ static const char zero[] = "0";
+
+ size_t bytes_written;
+
+ if (!last_initialized) {
+ last_tck = !swclk;
+ last_tms = !swdio;
+ last_initialized = 1;
+ }
+
+ if (last_tms_drive == 1 && swdio != last_tms) {
+ bytes_written = write(tms_fd, swdio ? &one : &zero, 1);
+ if (bytes_written != 1)
+ LOG_WARNING("writing swdio (tms) failed");
+ }
+
+ /* write clk last */
+ if (swclk != last_tck) {
+ bytes_written = write(tck_fd, swclk ? &one : &zero, 1);
+ if (bytes_written != 1)
+ LOG_WARNING("writing swclk (tck) failed");
+ }
+
+ last_tms = swdio;
+ last_tck = swclk;
+}
/* helper func to close and cleanup files only if they were valid/ used */
static void cleanup_fd(int fd, int gpio)
char d = c - 'r';
sysfsgpio_reset(!!(d & 2),
(d & 1));
- } else if (c >= '0' && c <= '0' + 7) {/* Write */
+ } else if (c >= '0' && c <= '0' + 7) { /* Write */
char d = c - '0';
sysfsgpio_write(!!(d & 4),
!!(d & 2),
(d & 1));
} else if (c == 'R')
putchar(sysfsgpio_read());
+ else if (c == 'c') /* SWDIO read */
+ putchar(sysfsgpio_swdio_read());
+ else if (c == 'o' || c == 'O') /* SWDIO drive */
+ sysfsgpio_swdio_drive(c == 'o' ? 0 : 1);
+ else if (c >= 'd' && c <= 'g') { /* SWD write */
+ char d = c - 'd';
+ sysfsgpio_swd_write((d & 2), (d & 1));
+ }
else
LOG_ERROR("Unknown command '%c' received", c);
}
int main(int argc, char *argv[])
{
- LOG_WARNING("SysfsGPIO remote_bitbang JTAG driver\n");
+ LOG_WARNING("SysfsGPIO remote_bitbang JTAG+SWD driver\n");
for (int i = 1; i < argc; i++) {
if (!strcmp(argv[i], "tck"))
* Configure TDO as an input, and TDI, TCK, TMS, TRST, SRST
* as outputs. Drive TDI and TCK low, and TMS/TRST/SRST high.
*/
- tck_fd = setup_sysfs_gpio(tck_gpio, 1, 0);
+ tck_fd = setup_sysfs_gpio(tck_gpio, 1, 0, 0);
if (tck_fd < 0)
goto out_error;
- tms_fd = setup_sysfs_gpio(tms_gpio, 1, 1);
+ tms_fd = setup_sysfs_gpio(tms_gpio, 1, 1, 1);
if (tms_fd < 0)
goto out_error;
+ last_tms_drive = 0;
- tdi_fd = setup_sysfs_gpio(tdi_gpio, 1, 0);
+ tdi_fd = setup_sysfs_gpio(tdi_gpio, 1, 0, 0);
if (tdi_fd < 0)
goto out_error;
- tdo_fd = setup_sysfs_gpio(tdo_gpio, 0, 0);
+ tdo_fd = setup_sysfs_gpio(tdo_gpio, 0, 0, 0);
if (tdo_fd < 0)
goto out_error;
/* assume active low */
if (trst_gpio > 0) {
- trst_fd = setup_sysfs_gpio(trst_gpio, 1, 1);
+ trst_fd = setup_sysfs_gpio(trst_gpio, 1, 1, 0);
if (trst_fd < 0)
goto out_error;
}
/* assume active low */
if (srst_gpio > 0) {
- srst_fd = setup_sysfs_gpio(srst_gpio, 1, 1);
+ srst_fd = setup_sysfs_gpio(srst_gpio, 1, 1, 0);
if (srst_fd < 0)
goto out_error;
}
+ last_initialized = 0;
+
LOG_WARNING("SysfsGPIO nums: tck = %d, tms = %d, tdi = %d, tdo = %d",
tck_gpio, tms_gpio, tdi_gpio, tdo_gpio);
LOG_WARNING("SysfsGPIO num: srst = %d", srst_gpio);
Code Review / openocd.git / blobdiff