tools: add sample remote_bitbang sysfsgpio server

This adds a sample server that implements remote_bitbang protocol,
based on sysfsgpio interface driver.

Change-Id: I17633e91f819ab7b806606e1a1c38d5366ab4598
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/1403
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>

1 files changed, 408 insertions, 0 deletions

diff --git a/tools/remote_bitbang/remote_bitbang_sysfsgpio.c b/tools/remote_bitbang/remote_bitbang_sysfsgpio.c
new file mode 100644
index 00000000..e59a1bde
--- /dev/null
+++ b/tools/remote_bitbang/remote_bitbang_sysfsgpio.c
@@ -0,0 +1,408 @@
+/***************************************************************************
+ *   Copyright (C) 2013 Paul Fertser <fercerpav@gmail.com>                 *
+ *   Copyright (C) 2012 by Creative Product Design, marc @ cpdesign.com.au *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.           *
+ ***************************************************************************/
+
+/*
+  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
+*/
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#define LOG_ERROR(...)		do {					\
+		fprintf(stderr, __VA_ARGS__);				\
+		fputc('\n', stderr);					\
+	} while (0)
+#define LOG_WARNING(...)	LOG_ERROR(__VA_ARGS__)
+
+#define ERROR_OK	(-1)
+#define ERROR_FAIL	(-2)
+#define ERROR_JTAG_INIT_FAILED	ERROR_FAIL
+
+/*
+ * Helper func to determine if gpio number valid
+ *
+ * Assume here that there will be less than 1000 gpios on a system
+ */
+static int is_gpio_valid(int gpio)
+{
+	return gpio >= 0 && gpio < 1000;
+}
+
+/*
+ * Helper func to open, write to and close a file
+ * name and valstr must be null terminated.
+ *
+ * Returns negative on failure.
+ */
+static int open_write_close(const char *name, const char *valstr)
+{
+	int ret;
+	int fd = open(name, O_WRONLY);
+	if (fd < 0)
+		return fd;
+
+	ret = write(fd, valstr, strlen(valstr));
+	close(fd);
+
+	return ret;
+}
+
+/*
+ * Helper func to unexport gpio from sysfs
+ */
+static void unexport_sysfs_gpio(int gpio)
+{
+	char gpiostr[4];
+
+	if (!is_gpio_valid(gpio))
+		return;
+
+	snprintf(gpiostr, sizeof(gpiostr), "%d", gpio);
+	if (open_write_close("/sys/class/gpio/unexport", gpiostr) < 0)
+		LOG_ERROR("Couldn't unexport gpio %d", gpio);
+
+	return;
+}
+
+/*
+ * Exports and sets up direction for gpio.
+ * If the gpio is an output, it is initialized according to init_high,
+ * otherwise it is ignored.
+ *
+ * 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)
+{
+	char buf[40];
+	char gpiostr[4];
+	int ret;
+
+	if (!is_gpio_valid(gpio))
+		return ERROR_OK;
+
+	snprintf(gpiostr, sizeof(gpiostr), "%d", gpio);
+	ret = open_write_close("/sys/class/gpio/export", gpiostr);
+	if (ret < 0) {
+		if (errno == EBUSY) {
+			LOG_WARNING("gpio %d is already exported", gpio);
+		} else {
+			LOG_ERROR("Couldn't export gpio %d", gpio);
+			perror("sysfsgpio: ");
+			return ERROR_FAIL;
+		}
+	}
+
+	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;
+	}
+
+	snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/value", gpio);
+	if (is_output)
+		ret = open(buf, O_WRONLY | O_NONBLOCK | O_SYNC);
+	else
+		ret = open(buf, O_RDONLY | O_NONBLOCK | O_SYNC);
+
+	if (ret < 0)
+		unexport_sysfs_gpio(gpio);
+
+	return ret;
+}
+
+/*
+ * file descriptors for /sys/class/gpio/gpioXX/value
+ * Set up during init.
+ */
+static int tck_fd = -1;
+static int tms_fd = -1;
+static int tdi_fd = -1;
+static int tdo_fd = -1;
+static int trst_fd = -1;
+static int srst_fd = -1;
+
+/*
+ * Bitbang interface read of TDO
+ *
+ * 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_read(void)
+{
+	char buf[1];
+
+	/* important to seek to signal sysfs of new read */
+	lseek(tdo_fd, 0, SEEK_SET);
+	int ret = read(tdo_fd, &buf, sizeof(buf));
+
+	if (ret < 0) {
+		LOG_WARNING("reading tdo failed");
+		return 0;
+	}
+
+	return buf[0];
+}
+
+/*
+ * 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.
+ */
+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) {
+		last_tck = !tck;
+		last_tms = !tms;
+		last_tdi = !tdi;
+		first_time = 1;
+	}
+
+	if (tdi != last_tdi) {
+		bytes_written = write(tdi_fd, tdi ? &one : &zero, 1);
+		if (bytes_written != 1)
+			LOG_WARNING("writing tdi failed");
+	}
+
+	if (tms != last_tms) {
+		bytes_written = write(tms_fd, tms ? &one : &zero, 1);
+		if (bytes_written != 1)
+			LOG_WARNING("writing tms failed");
+	}
+
+	/* write clk last */
+	if (tck != last_tck) {
+		bytes_written = write(tck_fd, tck ? &one : &zero, 1);
+		if (bytes_written != 1)
+			LOG_WARNING("writing tck failed");
+	}
+
+	last_tdi = tdi;
+	last_tms = tms;
+	last_tck = tck;
+}
+
+/*
+ * Bitbang interface to manipulate reset lines SRST and TRST
+ *
+ * (1) assert or (0) deassert reset lines
+ */
+static void sysfsgpio_reset(int trst, int srst)
+{
+	const char one[] = "1";
+	const char zero[] = "0";
+	size_t bytes_written;
+
+	/* assume active low */
+	if (srst_fd >= 0) {
+		bytes_written = write(srst_fd, srst ? &zero : &one, 1);
+		if (bytes_written != 1)
+			LOG_WARNING("writing srst failed");
+	}
+
+	/* assume active low */
+	if (trst_fd >= 0) {
+		bytes_written = write(trst_fd, trst ? &zero : &one, 1);
+		if (bytes_written != 1)
+			LOG_WARNING("writing trst failed");
+	}
+}
+
+/* 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;
+
+/* helper func to close and cleanup files only if they were valid/ used */
+static void cleanup_fd(int fd, int gpio)
+{
+	if (gpio >= 0) {
+		if (fd >= 0)
+			close(fd);
+
+		unexport_sysfs_gpio(gpio);
+	}
+}
+
+static void cleanup_all_fds(void)
+{
+	cleanup_fd(tck_fd, tck_gpio);
+	cleanup_fd(tms_fd, tms_gpio);
+	cleanup_fd(tdi_fd, tdi_gpio);
+	cleanup_fd(tdo_fd, tdo_gpio);
+	cleanup_fd(trst_fd, trst_gpio);
+	cleanup_fd(srst_fd, srst_gpio);
+}
+
+static void process_remote_protocol(void)
+{
+	int c;
+	while (1) {
+		c = getchar();
+		if (c == EOF || c == 'Q') /* Quit */
+			break;
+		else if (c == 'b' || c == 'B') /* Blink */
+			continue;
+		else if (c >= 'r' && c <= 'r' + 2) { /* Reset */
+			char d = c - 'r';
+			sysfsgpio_reset(!!(d & 2),
+					(d & 1));
+		} 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
+			LOG_ERROR("Unknown command '%c' received", c);
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	LOG_WARNING("SysfsGPIO remote_bitbang JTAG driver\n");
+
+	for (int i = 1; i < argc; i++) {
+		if (!strcmp(argv[i], "tck"))
+			tck_gpio = atoi(argv[++i]);
+		else if (!strcmp(argv[i], "tms"))
+			tms_gpio = atoi(argv[++i]);
+		else if (!strcmp(argv[i], "tdo"))
+			tdo_gpio = atoi(argv[++i]);
+		else if (!strcmp(argv[i], "tdi"))
+			tdi_gpio = atoi(argv[++i]);
+		else if (!strcmp(argv[i], "trst"))
+			trst_gpio = atoi(argv[++i]);
+		else if (!strcmp(argv[i], "srst"))
+			srst_gpio = atoi(argv[++i]);
+		else {
+			LOG_ERROR("Usage:\n%s ((tck|tms|tdo|tdi|trst|srst) num)*", argv[0]);
+			return -1;
+		}
+	}
+
+	if (!(is_gpio_valid(tck_gpio)
+			&& is_gpio_valid(tms_gpio)
+			&& is_gpio_valid(tdi_gpio)
+			&& is_gpio_valid(tdo_gpio))) {
+		if (!is_gpio_valid(tck_gpio))
+			LOG_ERROR("gpio num for tck is invalid");
+		if (!is_gpio_valid(tms_gpio))
+			LOG_ERROR("gpio num for tms is invalid");
+		if (!is_gpio_valid(tdo_gpio))
+			LOG_ERROR("gpio num for tdo is invalid");
+		if (!is_gpio_valid(tdi_gpio))
+			LOG_ERROR("gpio num for tdi is invalid");
+
+		LOG_ERROR("Require tck, tms, tdi and tdo gpios to all be specified");
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	/*
+	 * 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);
+	if (tck_fd < 0)
+		goto out_error;
+
+	tms_fd = setup_sysfs_gpio(tms_gpio, 1, 1);
+	if (tms_fd < 0)
+		goto out_error;
+
+	tdi_fd = setup_sysfs_gpio(tdi_gpio, 1, 0);
+	if (tdi_fd < 0)
+		goto out_error;
+
+	tdo_fd = setup_sysfs_gpio(tdo_gpio, 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);
+		if (trst_fd < 0)
+			goto out_error;
+	}
+
+	/* assume active low */
+	if (srst_gpio > 0) {
+		srst_fd = setup_sysfs_gpio(srst_gpio, 1, 1);
+		if (srst_fd < 0)
+			goto out_error;
+	}
+
+	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);
+	LOG_WARNING("SysfsGPIO num: trst = %d", trst_gpio);
+
+	setvbuf(stdout, NULL, _IONBF, 0);
+	process_remote_protocol();
+
+	cleanup_all_fds();
+	return 0;
+out_error:
+	cleanup_all_fds();
+	return ERROR_JTAG_INIT_FAILED;
+}