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| -rw-r--r-- | tools/remote_bitbang/remote_bitbang_sysfsgpio.c | 408 |
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; +} |