407 lines
10 KiB
C
407 lines
10 KiB
C
/***************************************************************************
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* Copyright (C) 2013 Paul Fertser <fercerpav@gmail.com> *
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* Copyright (C) 2012 by Creative Product Design, marc @ cpdesign.com.au *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program. If not, see <http://www.gnu.org/licenses/>. *
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***************************************************************************/
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/*
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This is a test application to be used as a remote bitbang server for
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the OpenOCD remote_bitbang interface driver.
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To compile run:
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gcc -Wall -ansi -pedantic -std=c99 -o remote_bitbang_sysfsgpio remote_bitbang_sysfsgpio.c
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Usage example:
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On Raspberry Pi run:
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socat TCP6-LISTEN:7777,fork EXEC:"sudo ./remote_bitbang_sysfsgpio tck 11 tms 25 tdo 9 tdi 10"
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On host run:
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openocd -c "interface remote_bitbang; remote_bitbang host raspberrypi; remote_bitbang port 7777" \
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-f target/stm32f1x.cfg
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Or if you want to test UNIX sockets, run both on Raspberry Pi:
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socat UNIX-LISTEN:/tmp/remotebitbang-socket,fork EXEC:"sudo ./remote_bitbang_sysfsgpio tck 11 tms 25 tdo 9 tdi 10"
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openocd -c "interface remote_bitbang; remote_bitbang host /tmp/remotebitbang-socket" -f target/stm32f1x.cfg
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <errno.h>
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#define LOG_ERROR(...) do { \
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fprintf(stderr, __VA_ARGS__); \
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fputc('\n', stderr); \
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} while (0)
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#define LOG_WARNING(...) LOG_ERROR(__VA_ARGS__)
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#define ERROR_OK (-1)
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#define ERROR_FAIL (-2)
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#define ERROR_JTAG_INIT_FAILED ERROR_FAIL
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/*
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* Helper func to determine if gpio number valid
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*
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* Assume here that there will be less than 1000 gpios on a system
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*/
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static int is_gpio_valid(int gpio)
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{
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return gpio >= 0 && gpio < 1000;
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}
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/*
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* Helper func to open, write to and close a file
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* name and valstr must be null terminated.
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*
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* Returns negative on failure.
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*/
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static int open_write_close(const char *name, const char *valstr)
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{
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int ret;
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int fd = open(name, O_WRONLY);
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if (fd < 0)
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return fd;
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ret = write(fd, valstr, strlen(valstr));
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close(fd);
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return ret;
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}
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/*
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* Helper func to unexport gpio from sysfs
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*/
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static void unexport_sysfs_gpio(int gpio)
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{
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char gpiostr[4];
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if (!is_gpio_valid(gpio))
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return;
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snprintf(gpiostr, sizeof(gpiostr), "%d", gpio);
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if (open_write_close("/sys/class/gpio/unexport", gpiostr) < 0)
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LOG_ERROR("Couldn't unexport gpio %d", gpio);
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return;
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}
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/*
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* Exports and sets up direction for gpio.
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* If the gpio is an output, it is initialized according to init_high,
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* otherwise it is ignored.
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*
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* If the gpio is already exported we just show a warning and continue; if
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* openocd happened to crash (or was killed by user) then the gpios will not
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* have been cleaned up.
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*/
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static int setup_sysfs_gpio(int gpio, int is_output, int init_high)
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{
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char buf[40];
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char gpiostr[4];
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int ret;
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if (!is_gpio_valid(gpio))
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return ERROR_OK;
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snprintf(gpiostr, sizeof(gpiostr), "%d", gpio);
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ret = open_write_close("/sys/class/gpio/export", gpiostr);
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if (ret < 0) {
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if (errno == EBUSY) {
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LOG_WARNING("gpio %d is already exported", gpio);
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} else {
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LOG_ERROR("Couldn't export gpio %d", gpio);
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perror("sysfsgpio: ");
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return ERROR_FAIL;
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}
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}
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snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/direction", gpio);
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ret = open_write_close(buf, is_output ? (init_high ? "high" : "low") : "in");
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if (ret < 0) {
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LOG_ERROR("Couldn't set direction for gpio %d", gpio);
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perror("sysfsgpio: ");
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unexport_sysfs_gpio(gpio);
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return ERROR_FAIL;
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}
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snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/value", gpio);
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if (is_output)
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ret = open(buf, O_WRONLY | O_NONBLOCK | O_SYNC);
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else
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ret = open(buf, O_RDONLY | O_NONBLOCK | O_SYNC);
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if (ret < 0)
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unexport_sysfs_gpio(gpio);
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return ret;
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}
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/*
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* file descriptors for /sys/class/gpio/gpioXX/value
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* Set up during init.
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*/
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static int tck_fd = -1;
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static int tms_fd = -1;
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static int tdi_fd = -1;
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static int tdo_fd = -1;
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static int trst_fd = -1;
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static int srst_fd = -1;
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/*
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* Bitbang interface read of TDO
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*
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* The sysfs value will read back either '0' or '1'. The trick here is to call
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* lseek to bypass buffering in the sysfs kernel driver.
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*/
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static int sysfsgpio_read(void)
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{
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char buf[1];
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/* important to seek to signal sysfs of new read */
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lseek(tdo_fd, 0, SEEK_SET);
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int ret = read(tdo_fd, &buf, sizeof(buf));
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if (ret < 0) {
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LOG_WARNING("reading tdo failed");
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return 0;
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}
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return buf[0];
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}
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/*
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* Bitbang interface write of TCK, TMS, TDI
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*
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* Seeing as this is the only function where the outputs are changed,
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* we can cache the old value to avoid needlessly writing it.
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*/
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static void sysfsgpio_write(int tck, int tms, int tdi)
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{
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const char one[] = "1";
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const char zero[] = "0";
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static int last_tck;
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static int last_tms;
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static int last_tdi;
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static int first_time;
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size_t bytes_written;
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if (!first_time) {
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last_tck = !tck;
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last_tms = !tms;
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last_tdi = !tdi;
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first_time = 1;
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}
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if (tdi != last_tdi) {
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bytes_written = write(tdi_fd, tdi ? &one : &zero, 1);
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if (bytes_written != 1)
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LOG_WARNING("writing tdi failed");
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}
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if (tms != last_tms) {
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bytes_written = write(tms_fd, tms ? &one : &zero, 1);
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if (bytes_written != 1)
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LOG_WARNING("writing tms failed");
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}
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/* write clk last */
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if (tck != last_tck) {
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bytes_written = write(tck_fd, tck ? &one : &zero, 1);
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if (bytes_written != 1)
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LOG_WARNING("writing tck failed");
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}
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last_tdi = tdi;
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last_tms = tms;
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last_tck = tck;
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}
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/*
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* Bitbang interface to manipulate reset lines SRST and TRST
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*
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* (1) assert or (0) deassert reset lines
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*/
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static void sysfsgpio_reset(int trst, int srst)
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{
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const char one[] = "1";
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const char zero[] = "0";
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size_t bytes_written;
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/* assume active low */
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if (srst_fd >= 0) {
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bytes_written = write(srst_fd, srst ? &zero : &one, 1);
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if (bytes_written != 1)
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LOG_WARNING("writing srst failed");
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}
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/* assume active low */
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if (trst_fd >= 0) {
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bytes_written = write(trst_fd, trst ? &zero : &one, 1);
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if (bytes_written != 1)
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LOG_WARNING("writing trst failed");
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}
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}
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/* gpio numbers for each gpio. Negative values are invalid */
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static int tck_gpio = -1;
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static int tms_gpio = -1;
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static int tdi_gpio = -1;
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static int tdo_gpio = -1;
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static int trst_gpio = -1;
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static int srst_gpio = -1;
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/* helper func to close and cleanup files only if they were valid/ used */
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static void cleanup_fd(int fd, int gpio)
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{
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if (gpio >= 0) {
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if (fd >= 0)
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close(fd);
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unexport_sysfs_gpio(gpio);
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}
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}
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static void cleanup_all_fds(void)
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{
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cleanup_fd(tck_fd, tck_gpio);
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cleanup_fd(tms_fd, tms_gpio);
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cleanup_fd(tdi_fd, tdi_gpio);
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cleanup_fd(tdo_fd, tdo_gpio);
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cleanup_fd(trst_fd, trst_gpio);
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cleanup_fd(srst_fd, srst_gpio);
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}
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static void process_remote_protocol(void)
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{
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int c;
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while (1) {
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c = getchar();
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if (c == EOF || c == 'Q') /* Quit */
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break;
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else if (c == 'b' || c == 'B') /* Blink */
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continue;
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else if (c >= 'r' && c <= 'r' + 3) { /* Reset */
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char d = c - 'r';
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sysfsgpio_reset(!!(d & 2),
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(d & 1));
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} else if (c >= '0' && c <= '0' + 7) {/* Write */
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char d = c - '0';
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sysfsgpio_write(!!(d & 4),
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!!(d & 2),
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(d & 1));
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} else if (c == 'R')
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putchar(sysfsgpio_read());
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else
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LOG_ERROR("Unknown command '%c' received", c);
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}
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}
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int main(int argc, char *argv[])
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{
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LOG_WARNING("SysfsGPIO remote_bitbang JTAG driver\n");
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for (int i = 1; i < argc; i++) {
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if (!strcmp(argv[i], "tck"))
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tck_gpio = atoi(argv[++i]);
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else if (!strcmp(argv[i], "tms"))
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tms_gpio = atoi(argv[++i]);
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else if (!strcmp(argv[i], "tdo"))
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tdo_gpio = atoi(argv[++i]);
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else if (!strcmp(argv[i], "tdi"))
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tdi_gpio = atoi(argv[++i]);
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else if (!strcmp(argv[i], "trst"))
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trst_gpio = atoi(argv[++i]);
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else if (!strcmp(argv[i], "srst"))
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srst_gpio = atoi(argv[++i]);
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else {
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LOG_ERROR("Usage:\n%s ((tck|tms|tdo|tdi|trst|srst) num)*", argv[0]);
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return -1;
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}
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}
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if (!(is_gpio_valid(tck_gpio)
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&& is_gpio_valid(tms_gpio)
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&& is_gpio_valid(tdi_gpio)
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&& is_gpio_valid(tdo_gpio))) {
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if (!is_gpio_valid(tck_gpio))
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LOG_ERROR("gpio num for tck is invalid");
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if (!is_gpio_valid(tms_gpio))
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LOG_ERROR("gpio num for tms is invalid");
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if (!is_gpio_valid(tdo_gpio))
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LOG_ERROR("gpio num for tdo is invalid");
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if (!is_gpio_valid(tdi_gpio))
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LOG_ERROR("gpio num for tdi is invalid");
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LOG_ERROR("Require tck, tms, tdi and tdo gpios to all be specified");
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return ERROR_JTAG_INIT_FAILED;
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}
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/*
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* Configure TDO as an input, and TDI, TCK, TMS, TRST, SRST
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* as outputs. Drive TDI and TCK low, and TMS/TRST/SRST high.
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*/
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tck_fd = setup_sysfs_gpio(tck_gpio, 1, 0);
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if (tck_fd < 0)
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goto out_error;
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tms_fd = setup_sysfs_gpio(tms_gpio, 1, 1);
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if (tms_fd < 0)
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goto out_error;
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tdi_fd = setup_sysfs_gpio(tdi_gpio, 1, 0);
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if (tdi_fd < 0)
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goto out_error;
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tdo_fd = setup_sysfs_gpio(tdo_gpio, 0, 0);
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if (tdo_fd < 0)
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goto out_error;
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/* assume active low */
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if (trst_gpio > 0) {
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trst_fd = setup_sysfs_gpio(trst_gpio, 1, 1);
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if (trst_fd < 0)
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goto out_error;
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}
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/* assume active low */
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if (srst_gpio > 0) {
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srst_fd = setup_sysfs_gpio(srst_gpio, 1, 1);
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if (srst_fd < 0)
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goto out_error;
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}
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LOG_WARNING("SysfsGPIO nums: tck = %d, tms = %d, tdi = %d, tdo = %d",
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tck_gpio, tms_gpio, tdi_gpio, tdo_gpio);
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LOG_WARNING("SysfsGPIO num: srst = %d", srst_gpio);
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LOG_WARNING("SysfsGPIO num: trst = %d", trst_gpio);
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setvbuf(stdout, NULL, _IONBF, 0);
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process_remote_protocol();
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cleanup_all_fds();
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return 0;
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out_error:
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cleanup_all_fds();
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return ERROR_JTAG_INIT_FAILED;
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}
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