From e290cb76c8d5abfe3929dc9436b936708684d989 Mon Sep 17 00:00:00 2001 From: Jean-Christian de Rivaz Date: Thu, 11 Dec 2014 17:50:33 +0100 Subject: [PATCH] Add SWD protocol support to sysfsgpio Based on the initial work on bcm2835gpio.c by Paul Fertser with many additions. Modifications to the GPIO handling was minimal in this patch. A more big modification is required before cleanup the interface between bitbang and sysfsgpio. Change-Id: I54bf2a2aa2ca059368b0e0e105dff6084b73d624 Signed-off-by: Jean-Christian de Rivaz Reviewed-on: http://openocd.zylin.com/2438 Tested-by: jenkins Reviewed-by: Spencer Oliver Reviewed-by: Paul Fertser --- src/jtag/drivers/sysfsgpio.c | 278 +++++++++++++++++++++++++++++------ 1 file changed, 229 insertions(+), 49 deletions(-) diff --git a/src/jtag/drivers/sysfsgpio.c b/src/jtag/drivers/sysfsgpio.c index dfb4dcb3..d822562a 100644 --- a/src/jtag/drivers/sysfsgpio.c +++ b/src/jtag/drivers/sysfsgpio.c @@ -16,6 +16,10 @@ * Free Software Foundation, Inc., * * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. * ***************************************************************************/ + +/* 2014-12: Addition of the SWD protocol support is based on the initial work + * on bcm2835gpio.c by Paul Fertser and modifications by Jean-Christian de Rivaz. */ + /** * @file * This driver implements a bitbang jtag interface using gpio lines via @@ -139,17 +143,26 @@ static int setup_sysfs_gpio(int gpio, int is_output, int init_high) } 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) + ret = open(buf, O_RDWR | O_NONBLOCK | O_SYNC); + if (ret < 0) { + LOG_ERROR("Couldn't open value for gpio %d", gpio); + perror("sysfsgpio: "); unexport_sysfs_gpio(gpio); + } return ret; } +/* 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; +static int swclk_gpio = -1; +static int swdio_gpio = -1; + /* * file descriptors for /sys/class/gpio/gpioXX/value * Set up during init. @@ -160,6 +173,72 @@ static int tdi_fd = -1; static int tdo_fd = -1; static int trst_fd = -1; static int srst_fd = -1; +static int swclk_fd = -1; +static int swdio_fd = -1; + +static int last_swclk; +static int last_swdio; +static bool last_stored; +static bool swdio_input; + +static void sysfsgpio_swdio_drive(bool is_output) +{ + char buf[40]; + int ret; + + snprintf(buf, sizeof(buf), "/sys/class/gpio/gpio%d/direction", swdio_gpio); + ret = open_write_close(buf, is_output ? "high" : "in"); + if (ret < 0) { + LOG_ERROR("Couldn't set direction for gpio %d", swdio_gpio); + perror("sysfsgpio: "); + } + + last_stored = false; + swdio_input = !is_output; +} + +static int sysfsgpio_swdio_read(void) +{ + char buf[1]; + + /* important to seek to signal sysfs of new read */ + lseek(swdio_fd, 0, SEEK_SET); + int ret = read(swdio_fd, &buf, sizeof(buf)); + + if (ret < 0) { + LOG_WARNING("reading swdio failed"); + return 0; + } + + return buf[0] == '1'; +} + +static void sysfsgpio_swdio_write(int swclk, int swdio) +{ + const char one[] = "1"; + const char zero[] = "0"; + + size_t bytes_written; + + if (!swdio_input) { + if (!last_stored || (swdio != last_swdio)) { + bytes_written = write(swdio_fd, swdio ? &one : &zero, 1); + if (bytes_written != 1) + LOG_WARNING("writing swdio failed"); + } + } + + /* write swclk last */ + if (!last_stored || (swclk != last_swclk)) { + bytes_written = write(swclk_fd, swclk ? &one : &zero, 1); + if (bytes_written != 1) + LOG_WARNING("writing swclk failed"); + } + + last_swdio = swdio; + last_swclk = swclk; + last_stored = true; +} /* * Bitbang interface read of TDO @@ -191,6 +270,11 @@ static int sysfsgpio_read(void) */ static void sysfsgpio_write(int tck, int tms, int tdi) { + if (swd_mode) { + sysfsgpio_swdio_write(tck, tdi); + return; + } + const char one[] = "1"; const char zero[] = "0"; @@ -239,6 +323,7 @@ static void sysfsgpio_write(int tck, int tms, int tdi) */ static void sysfsgpio_reset(int trst, int srst) { + LOG_DEBUG("sysfsgpio_reset"); const char one[] = "1"; const char zero[] = "0"; size_t bytes_written; @@ -258,14 +343,6 @@ static void sysfsgpio_reset(int trst, int srst) } } -/* 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; - COMMAND_HANDLER(sysfsgpio_handle_jtag_gpionums) { if (CMD_ARGC == 4) { @@ -338,6 +415,40 @@ COMMAND_HANDLER(sysfsgpio_handle_jtag_gpionum_trst) return ERROR_OK; } +COMMAND_HANDLER(sysfsgpio_handle_swd_gpionums) +{ + if (CMD_ARGC == 2) { + COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swclk_gpio); + COMMAND_PARSE_NUMBER(int, CMD_ARGV[1], swdio_gpio); + } else if (CMD_ARGC != 0) { + return ERROR_COMMAND_SYNTAX_ERROR; + } + + command_print(CMD_CTX, + "SysfsGPIO nums: swclk = %d, swdio = %d", + swclk_gpio, swdio_gpio); + + return ERROR_OK; +} + +COMMAND_HANDLER(sysfsgpio_handle_swd_gpionum_swclk) +{ + if (CMD_ARGC == 1) + COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swclk_gpio); + + command_print(CMD_CTX, "SysfsGPIO num: swclk = %d", swclk_gpio); + return ERROR_OK; +} + +COMMAND_HANDLER(sysfsgpio_handle_swd_gpionum_swdio) +{ + if (CMD_ARGC == 1) + COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swdio_gpio); + + command_print(CMD_CTX, "SysfsGPIO num: swdio = %d", swdio_gpio); + return ERROR_OK; +} + static const struct command_registration sysfsgpio_command_handlers[] = { { .name = "sysfsgpio_jtag_nums", @@ -382,17 +493,39 @@ static const struct command_registration sysfsgpio_command_handlers[] = { .mode = COMMAND_CONFIG, .help = "gpio number for trst.", }, + { + .name = "sysfsgpio_swd_nums", + .handler = &sysfsgpio_handle_swd_gpionums, + .mode = COMMAND_CONFIG, + .help = "gpio numbers for swclk, swdio. (in that order)", + .usage = "(swclk swdio)* ", + }, + { + .name = "sysfsgpio_swclk_num", + .handler = &sysfsgpio_handle_swd_gpionum_swclk, + .mode = COMMAND_CONFIG, + .help = "gpio number for swclk.", + }, + { + .name = "sysfsgpio_swdio_num", + .handler = &sysfsgpio_handle_swd_gpionum_swdio, + .mode = COMMAND_CONFIG, + .help = "gpio number for swdio.", + }, COMMAND_REGISTRATION_DONE }; static int sysfsgpio_init(void); static int sysfsgpio_quit(void); +static const char * const sysfsgpio_transports[] = { "jtag", "swd", NULL }; + struct jtag_interface sysfsgpio_interface = { .name = "sysfsgpio", .supported = DEBUG_CAP_TMS_SEQ, .execute_queue = bitbang_execute_queue, - .transports = jtag_only, + .transports = sysfsgpio_transports, + .swd = &bitbang_swd, .commands = sysfsgpio_command_handlers, .init = sysfsgpio_init, .quit = sysfsgpio_quit, @@ -402,6 +535,8 @@ static struct bitbang_interface sysfsgpio_bitbang = { .read = sysfsgpio_read, .write = sysfsgpio_write, .reset = sysfsgpio_reset, + .swdio_read = sysfsgpio_swdio_read, + .swdio_drive = sysfsgpio_swdio_drive, .blink = 0 }; @@ -426,68 +561,113 @@ static void cleanup_all_fds(void) cleanup_fd(srst_fd, srst_gpio); } +static bool sysfsgpio_jtag_mode_possible(void) +{ + if (!is_gpio_valid(tck_gpio)) + return 0; + if (!is_gpio_valid(tms_gpio)) + return 0; + if (!is_gpio_valid(tdi_gpio)) + return 0; + if (!is_gpio_valid(tdo_gpio)) + return 0; + return 1; +} + +static bool sysfsgpio_swd_mode_possible(void) +{ + if (!is_gpio_valid(swclk_gpio)) + return 0; + if (!is_gpio_valid(swdio_gpio)) + return 0; + return 1; +} + static int sysfsgpio_init(void) { bitbang_interface = &sysfsgpio_bitbang; - LOG_INFO("SysfsGPIO JTAG bitbang driver"); - - 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; - } + LOG_INFO("SysfsGPIO JTAG/SWD bitbang driver"); - if (!is_gpio_valid(trst_gpio) && !is_gpio_valid(srst_gpio)) { - LOG_ERROR("Require at least one of trst or srst gpios to be specified"); + if (sysfsgpio_jtag_mode_possible()) { + if (sysfsgpio_swd_mode_possible()) + LOG_INFO("JTAG and SWD modes enabled"); + else + LOG_INFO("JTAG only mode enabled (specify swclk and swdio gpio to add SWD mode)"); + if (!is_gpio_valid(trst_gpio) && !is_gpio_valid(srst_gpio)) { + LOG_ERROR("Require at least one of trst or srst gpios to be specified"); + return ERROR_JTAG_INIT_FAILED; + } + } else if (sysfsgpio_swd_mode_possible()) { + LOG_INFO("SWD only mode enabled (specify tck, tms, tdi and tdo gpios to add JTAG mode)"); + } else { + LOG_ERROR("Require tck, tms, tdi and tdo gpios for JTAG mode and/or swclk and swdio gpio for SWD mode"); 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. + * For SWD, SWCLK and SWDIO are configures as output high. */ - tck_fd = setup_sysfs_gpio(tck_gpio, 1, 0); - if (tck_fd < 0) - goto out_error; + if (tck_gpio >= 0) { + 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; + if (tms_gpio >= 0) { + 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; + if (tdi_gpio >= 0) { + 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; + if (tdo_gpio >= 0) { + tdo_fd = setup_sysfs_gpio(tdo_gpio, 0, 0); + if (tdo_fd < 0) + goto out_error; + } /* assume active low*/ - if (trst_gpio > 0) { + 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) { + if (srst_gpio >= 0) { srst_fd = setup_sysfs_gpio(srst_gpio, 1, 1); if (srst_fd < 0) goto out_error; } + if (swclk_gpio >= 0) { + swclk_fd = setup_sysfs_gpio(swclk_gpio, 1, 0); + if (swclk_fd < 0) + goto out_error; + } + + if (swdio_gpio >= 0) { + swdio_fd = setup_sysfs_gpio(swdio_gpio, 1, 0); + if (swdio_fd < 0) + goto out_error; + } + + if (sysfsgpio_swd_mode_possible()) { + if (swd_mode) + bitbang_swd_switch_seq(NULL, JTAG_TO_SWD); + else + bitbang_swd_switch_seq(NULL, SWD_TO_JTAG); + } + return ERROR_OK; out_error: -- 2.39.5