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 <jc@eclis.ch>
Reviewed-on: http://openocd.zylin.com/2438
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

diff --git a/src/jtag/drivers/sysfsgpio.c b/src/jtag/drivers/sysfsgpio.c
index dfb4dcb3cff3ab242e47678dcfc7b5afbb97f9b6..d822562a5e5953d2af3ba8999d367d2b4648f515 100644 (file)
--- 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.           *
  ***************************************************************************/
  *   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
 /**
  * @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);
        }
 
        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);
                unexport_sysfs_gpio(gpio);

+       }

 
        return ret;
 }
 
 
        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.
 /*
  * 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 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
 
 /*
  * Bitbang interface read of TDO


@@ -191,6 +270,11 @@ static int sysfsgpio_read(void)
  */
 static void sysfsgpio_write(int tck, int tms, int tdi)
 {
  */
 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";
 
        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)
 {
  */
 static void sysfsgpio_reset(int trst, int srst)
 {

+       LOG_DEBUG("sysfsgpio_reset");

        const char one[] = "1";
        const char zero[] = "0";
        size_t bytes_written;
        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) {
 COMMAND_HANDLER(sysfsgpio_handle_jtag_gpionums)
 {
        if (CMD_ARGC == 4) {


@@ -338,6 +415,40 @@ COMMAND_HANDLER(sysfsgpio_handle_jtag_gpionum_trst)
        return ERROR_OK;
 }
 
        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",
 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.",
        },
                .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);
 
        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,
 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,
        .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,
        .read = sysfsgpio_read,
        .write = sysfsgpio_write,
        .reset = sysfsgpio_reset,

+       .swdio_read = sysfsgpio_swdio_read,
+       .swdio_drive = sysfsgpio_swdio_drive,

        .blink = 0
 };
 
        .blink = 0
 };
 


@@ -426,68 +561,113 @@ static void cleanup_all_fds(void)
        cleanup_fd(srst_fd, srst_gpio);
 }
 
        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;
 
 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;
        }
 
                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.
        /*
         * 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*/
 
        /* 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*/
                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;
        }
 
                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:
        return ERROR_OK;
 
 out_error: