X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=blobdiff_plain;f=src%2Fjtag%2Fdrivers%2Fremote_bitbang.c;h=53d2151fdce7bf57c149ce35a13b6127938eec92;hp=f6691bb625a5483690ec44528eebbd78217dedf7;hb=HEAD;hpb=87668aebf1851c06af2513ab5f27ebb9ebf1ff16

diff --git a/src/jtag/drivers/remote_bitbang.c b/src/jtag/drivers/remote_bitbang.c
index f6691bb625..53d2151fdc 100644
--- a/src/jtag/drivers/remote_bitbang.c
+++ b/src/jtag/drivers/remote_bitbang.c
@@ -1,21 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
 /***************************************************************************
  *   Copyright (C) 2011 by Richard Uhler                                   *
  *   ruhler@mit.edu                                                        *
  *                                                                         *
- *   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.,                                       *
- *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
+ *   Copyright (C) 2021 by Manuel Wick <manuel@matronix.de>                *
  ***************************************************************************/
 
 #ifdef HAVE_CONFIG_H
@@ -25,215 +14,382 @@
 #ifndef _WIN32
 #include <sys/un.h>
 #include <netdb.h>
+#include <netinet/tcp.h>
 #endif
+#include "helper/system.h"
+#include "helper/replacements.h"
 #include <jtag/interface.h>
 #include "bitbang.h"
 
-#ifndef UNIX_PATH_LEN
-#define UNIX_PATH_LEN 108
-#endif
-
 /* arbitrary limit on host name length: */
 #define REMOTE_BITBANG_HOST_MAX 255
 
-#define REMOTE_BITBANG_RAISE_ERROR(expr ...) \
-	do { \
-		LOG_ERROR(expr); \
-		LOG_ERROR("Terminating openocd."); \
-		exit(-1); \
-	} while (0)
+static char *remote_bitbang_host;
+static char *remote_bitbang_port;
+
+static int remote_bitbang_fd;
+static uint8_t remote_bitbang_send_buf[512];
+static unsigned int remote_bitbang_send_buf_used;
 
-static char remote_bitbang_host[REMOTE_BITBANG_HOST_MAX] = "openocd";
-static uint16_t remote_bitbang_port;
+static bool use_remote_sleep;
 
-FILE *remote_bitbang_in;
-FILE *remote_bitbang_out;
+/* Circular buffer. When start == end, the buffer is empty. */
+static char remote_bitbang_recv_buf[256];
+static unsigned int remote_bitbang_recv_buf_start;
+static unsigned int remote_bitbang_recv_buf_end;
 
-static void remote_bitbang_putc(int c)
+static bool remote_bitbang_recv_buf_full(void)
 {
-	if (EOF == fputc(c, remote_bitbang_out))
-		REMOTE_BITBANG_RAISE_ERROR("remote_bitbang_putc: %s", strerror(errno));
+	return remote_bitbang_recv_buf_end ==
+		((remote_bitbang_recv_buf_start + sizeof(remote_bitbang_recv_buf) - 1) %
+		 sizeof(remote_bitbang_recv_buf));
 }
 
-static int remote_bitbang_quit(void)
+static bool remote_bitbang_recv_buf_empty(void)
 {
-	if (EOF == fputc('Q', remote_bitbang_out)) {
-		LOG_ERROR("fputs: %s", strerror(errno));
-		return ERROR_FAIL;
+	return remote_bitbang_recv_buf_start == remote_bitbang_recv_buf_end;
+}
+
+static unsigned int remote_bitbang_recv_buf_contiguous_available_space(void)
+{
+	if (remote_bitbang_recv_buf_end >= remote_bitbang_recv_buf_start) {
+		unsigned int space = sizeof(remote_bitbang_recv_buf) -
+				     remote_bitbang_recv_buf_end;
+		if (remote_bitbang_recv_buf_start == 0)
+			space -= 1;
+		return space;
+	} else {
+		return remote_bitbang_recv_buf_start -
+		       remote_bitbang_recv_buf_end - 1;
 	}
+}
 
-	if (EOF == fflush(remote_bitbang_out)) {
-		LOG_ERROR("fflush: %s", strerror(errno));
-		return ERROR_FAIL;
+static int remote_bitbang_flush(void)
+{
+	if (remote_bitbang_send_buf_used <= 0)
+		return ERROR_OK;
+
+	unsigned int offset = 0;
+	while (offset < remote_bitbang_send_buf_used) {
+		ssize_t written = write_socket(remote_bitbang_fd, remote_bitbang_send_buf + offset,
+									   remote_bitbang_send_buf_used - offset);
+		if (written < 0) {
+			log_socket_error("remote_bitbang_putc");
+			remote_bitbang_send_buf_used = 0;
+			return ERROR_FAIL;
+		}
+		offset += written;
 	}
+	remote_bitbang_send_buf_used = 0;
+	return ERROR_OK;
+}
 
-	/* We only need to close one of the FILE*s, because they both use the same */
-	/* underlying file descriptor. */
-	if (EOF == fclose(remote_bitbang_out)) {
-		LOG_ERROR("fclose: %s", strerror(errno));
-		return ERROR_FAIL;
+enum block_bool {
+	NO_BLOCK,
+	BLOCK
+};
+
+/* Read any incoming data, placing it into the buffer. */
+static int remote_bitbang_fill_buf(enum block_bool block)
+{
+	if (remote_bitbang_recv_buf_empty()) {
+		/* If the buffer is empty, reset it to 0 so we get more
+		 * contiguous space. */
+		remote_bitbang_recv_buf_start = 0;
+		remote_bitbang_recv_buf_end = 0;
+	}
+
+	if (block == BLOCK) {
+		if (remote_bitbang_flush() != ERROR_OK)
+			return ERROR_FAIL;
+		socket_block(remote_bitbang_fd);
+	}
+
+	bool first = true;
+	while (!remote_bitbang_recv_buf_full()) {
+		unsigned int contiguous_available_space =
+				remote_bitbang_recv_buf_contiguous_available_space();
+		ssize_t count = read_socket(remote_bitbang_fd,
+				remote_bitbang_recv_buf + remote_bitbang_recv_buf_end,
+				contiguous_available_space);
+		if (first && block == BLOCK)
+			socket_nonblock(remote_bitbang_fd);
+		first = false;
+		if (count > 0) {
+			remote_bitbang_recv_buf_end += count;
+			if (remote_bitbang_recv_buf_end == sizeof(remote_bitbang_recv_buf))
+				remote_bitbang_recv_buf_end = 0;
+		} else if (count == 0) {
+			return ERROR_OK;
+		} else if (count < 0) {
+#ifdef _WIN32
+			if (WSAGetLastError() == WSAEWOULDBLOCK) {
+#else
+			if (errno == EAGAIN) {
+#endif
+				return ERROR_OK;
+			} else {
+				log_socket_error("remote_bitbang_fill_buf");
+				return ERROR_FAIL;
+			}
+		}
 	}
 
-	LOG_INFO("remote_bitbang interface quit");
 	return ERROR_OK;
 }
 
-/* Get the next read response. */
-static int remote_bitbang_rread(void)
+typedef enum {
+	NO_FLUSH,
+	FLUSH_SEND_BUF
+} flush_bool_t;
+
+static int remote_bitbang_queue(int c, flush_bool_t flush)
 {
-	if (EOF == fflush(remote_bitbang_out)) {
-		remote_bitbang_quit();
-		REMOTE_BITBANG_RAISE_ERROR("fflush: %s", strerror(errno));
+	remote_bitbang_send_buf[remote_bitbang_send_buf_used++] = c;
+	if (flush == FLUSH_SEND_BUF ||
+			remote_bitbang_send_buf_used >= ARRAY_SIZE(remote_bitbang_send_buf))
+		return remote_bitbang_flush();
+	return ERROR_OK;
+}
+
+static int remote_bitbang_quit(void)
+{
+	if (remote_bitbang_queue('Q', FLUSH_SEND_BUF) == ERROR_FAIL)
+		return ERROR_FAIL;
+
+	if (close_socket(remote_bitbang_fd) != 0) {
+		log_socket_error("close_socket");
+		return ERROR_FAIL;
 	}
 
-	int c = fgetc(remote_bitbang_in);
+	free(remote_bitbang_host);
+	free(remote_bitbang_port);
+
+	LOG_INFO("remote_bitbang interface quit");
+	return ERROR_OK;
+}
+
+static bb_value_t char_to_int(int c)
+{
 	switch (c) {
 		case '0':
-			return 0;
+			return BB_LOW;
 		case '1':
-			return 1;
+			return BB_HIGH;
 		default:
 			remote_bitbang_quit();
-			REMOTE_BITBANG_RAISE_ERROR(
-					"remote_bitbang: invalid read response: %c(%i)", c, c);
+			LOG_ERROR("remote_bitbang: invalid read response: %c(%i)", c, c);
+			return BB_ERROR;
 	}
 }
 
-static int remote_bitbang_read(void)
+static int remote_bitbang_sample(void)
 {
-	remote_bitbang_putc('R');
-	return remote_bitbang_rread();
+	if (remote_bitbang_fill_buf(NO_BLOCK) != ERROR_OK)
+		return ERROR_FAIL;
+	assert(!remote_bitbang_recv_buf_full());
+	return remote_bitbang_queue('R', NO_FLUSH);
 }
 
-static void remote_bitbang_write(int tck, int tms, int tdi)
+static bb_value_t remote_bitbang_read_sample(void)
+{
+	if (remote_bitbang_recv_buf_empty()) {
+		if (remote_bitbang_fill_buf(BLOCK) != ERROR_OK)
+			return BB_ERROR;
+	}
+	assert(!remote_bitbang_recv_buf_empty());
+	int c = remote_bitbang_recv_buf[remote_bitbang_recv_buf_start];
+	remote_bitbang_recv_buf_start =
+		(remote_bitbang_recv_buf_start + 1) % sizeof(remote_bitbang_recv_buf);
+	return char_to_int(c);
+}
+
+static int remote_bitbang_write(int tck, int tms, int tdi)
 {
 	char c = '0' + ((tck ? 0x4 : 0x0) | (tms ? 0x2 : 0x0) | (tdi ? 0x1 : 0x0));
-	remote_bitbang_putc(c);
+	return remote_bitbang_queue(c, NO_FLUSH);
 }
 
-static void remote_bitbang_reset(int trst, int srst)
+static int remote_bitbang_reset(int trst, int srst)
 {
 	char c = 'r' + ((trst ? 0x2 : 0x0) | (srst ? 0x1 : 0x0));
-	remote_bitbang_putc(c);
+	/* Always flush the send buffer on reset, because the reset call need not be
+	 * followed by jtag_execute_queue(). */
+	return remote_bitbang_queue(c, FLUSH_SEND_BUF);
 }
 
-static void remote_bitbang_blink(int on)
+static int remote_bitbang_sleep(unsigned int microseconds)
+{
+	if (!use_remote_sleep) {
+		jtag_sleep(microseconds);
+		return ERROR_OK;
+	}
+
+	int tmp;
+	unsigned int ms = microseconds / 1000;
+	unsigned int us = microseconds % 1000;
+
+	for (unsigned int i = 0; i < ms; i++) {
+		tmp = remote_bitbang_queue('Z', NO_FLUSH);
+		if (tmp != ERROR_OK)
+			return tmp;
+	}
+
+	for (unsigned int i = 0; i < us; i++) {
+		tmp = remote_bitbang_queue('z', NO_FLUSH);
+		if (tmp != ERROR_OK)
+			return tmp;
+	}
+
+	return remote_bitbang_flush();
+}
+
+static int remote_bitbang_blink(int on)
 {
 	char c = on ? 'B' : 'b';
-	remote_bitbang_putc(c);
+	return remote_bitbang_queue(c, FLUSH_SEND_BUF);
+}
+
+static void remote_bitbang_swdio_drive(bool is_output)
+{
+	char c = is_output ? 'O' : 'o';
+	if (remote_bitbang_queue(c, FLUSH_SEND_BUF) == ERROR_FAIL)
+		LOG_ERROR("Error setting direction for swdio");
+}
+
+static int remote_bitbang_swdio_read(void)
+{
+	if (remote_bitbang_queue('c', FLUSH_SEND_BUF) != ERROR_FAIL)
+		return remote_bitbang_read_sample();
+	else
+		return BB_ERROR;
+}
+
+static int remote_bitbang_swd_write(int swclk, int swdio)
+{
+	char c = 'd' + ((swclk ? 0x2 : 0x0) | (swdio ? 0x1 : 0x0));
+	return remote_bitbang_queue(c, NO_FLUSH);
 }
 
 static struct bitbang_interface remote_bitbang_bitbang = {
-	.read = &remote_bitbang_read,
+	.buf_size = sizeof(remote_bitbang_recv_buf) - 1,
+	.sample = &remote_bitbang_sample,
+	.read_sample = &remote_bitbang_read_sample,
 	.write = &remote_bitbang_write,
-	.reset = &remote_bitbang_reset,
+	.swdio_read = &remote_bitbang_swdio_read,
+	.swdio_drive = &remote_bitbang_swdio_drive,
+	.swd_write = &remote_bitbang_swd_write,
 	.blink = &remote_bitbang_blink,
+	.sleep = &remote_bitbang_sleep,
+	.flush = &remote_bitbang_flush,
 };
 
 static int remote_bitbang_init_tcp(void)
 {
-	LOG_INFO("Connecting to %s:%i", remote_bitbang_host, remote_bitbang_port);
-	int fd = socket(PF_INET, SOCK_STREAM, 0);
-	if (fd < 0) {
-		LOG_ERROR("socket: %s", strerror(errno));
+	struct addrinfo hints = { .ai_family = AF_UNSPEC, .ai_socktype = SOCK_STREAM };
+	struct addrinfo *result, *rp;
+	int fd = 0;
+
+	LOG_INFO("Connecting to %s:%s",
+			remote_bitbang_host ? remote_bitbang_host : "localhost",
+			remote_bitbang_port);
+
+	/* Obtain address(es) matching host/port */
+	int s = getaddrinfo(remote_bitbang_host, remote_bitbang_port, &hints, &result);
+	if (s != 0) {
+		LOG_ERROR("getaddrinfo: %s\n", gai_strerror(s));
 		return ERROR_FAIL;
 	}
 
-	struct hostent *hent = gethostbyname(remote_bitbang_host);
-	if (hent == NULL) {
-		char *errorstr = "???";
-		switch (h_errno) {
-			case HOST_NOT_FOUND:
-				errorstr = "host not found";
-				break;
-			case NO_ADDRESS:
-				errorstr = "no address";
-				break;
-			case NO_RECOVERY:
-				errorstr = "no recovery";
-				break;
-			case TRY_AGAIN:
-				errorstr = "try again";
-				break;
-		}
-		LOG_ERROR("gethostbyname: %s", errorstr);
-		return ERROR_FAIL;
-	}
+	/* getaddrinfo() returns a list of address structures.
+	 Try each address until we successfully connect(2).
+	 If socket(2) (or connect(2)) fails, we (close the socket
+	 and) try the next address. */
 
-	struct sockaddr_in addr;
-	addr.sin_family = AF_INET;
-	addr.sin_port = htons(remote_bitbang_port);
-	addr.sin_addr = *(struct in_addr *)hent->h_addr;
-	if (connect(fd, (struct sockaddr *)&addr, sizeof(struct sockaddr_in)) < 0) {
-		LOG_ERROR("connect: %s", strerror(errno));
-		return ERROR_FAIL;
-	}
+	for (rp = result; rp ; rp = rp->ai_next) {
+		fd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+		if (fd == -1)
+			continue;
 
-	remote_bitbang_in = fdopen(fd, "r");
-	if (remote_bitbang_in == NULL) {
-		LOG_ERROR("fdopen: failed to open read stream");
-		return ERROR_FAIL;
+		if (connect(fd, rp->ai_addr, rp->ai_addrlen) != -1)
+			break; /* Success */
+
+		close(fd);
 	}
 
-	remote_bitbang_out = fdopen(fd, "w");
-	if (remote_bitbang_out == NULL) {
-		LOG_ERROR("fdopen: failed to open write stream");
+	/* We work hard to collapse the writes into the minimum number, so when
+	 * we write something we want to get it to the other end of the
+	 * connection as fast as possible. */
+	int one = 1;
+	/* On Windows optval has to be a const char *. */
+	setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (const char *)&one, sizeof(one));
+
+	freeaddrinfo(result); /* No longer needed */
+
+	if (!rp) { /* No address succeeded */
+		log_socket_error("Failed to connect");
 		return ERROR_FAIL;
 	}
 
-	LOG_INFO("remote_bitbang driver initialized");
-	return ERROR_OK;
+	return fd;
 }
 
 static int remote_bitbang_init_unix(void)
 {
+	if (!remote_bitbang_host) {
+		LOG_ERROR("host/socket not specified");
+		return ERROR_FAIL;
+	}
+
 	LOG_INFO("Connecting to unix socket %s", remote_bitbang_host);
 	int fd = socket(PF_UNIX, SOCK_STREAM, 0);
 	if (fd < 0) {
-		LOG_ERROR("socket: %s", strerror(errno));
+		log_socket_error("socket");
 		return ERROR_FAIL;
 	}
 
 	struct sockaddr_un addr;
 	addr.sun_family = AF_UNIX;
-	strncpy(addr.sun_path, remote_bitbang_host, UNIX_PATH_LEN);
-	addr.sun_path[UNIX_PATH_LEN-1] = '\0';
+	strncpy(addr.sun_path, remote_bitbang_host, sizeof(addr.sun_path));
+	addr.sun_path[sizeof(addr.sun_path)-1] = '\0';
 
 	if (connect(fd, (struct sockaddr *)&addr, sizeof(struct sockaddr_un)) < 0) {
-		LOG_ERROR("connect: %s", strerror(errno));
-		return ERROR_FAIL;
-	}
-
-	remote_bitbang_in = fdopen(fd, "r");
-	if (remote_bitbang_in == NULL) {
-		LOG_ERROR("fdopen: failed to open read stream");
-		return ERROR_FAIL;
-	}
-
-	remote_bitbang_out = fdopen(fd, "w");
-	if (remote_bitbang_out == NULL) {
-		LOG_ERROR("fdopen: failed to open write stream");
+		log_socket_error("connect");
 		return ERROR_FAIL;
 	}
 
-	LOG_INFO("remote_bitbang driver initialized");
-	return ERROR_OK;
+	return fd;
 }
 
 static int remote_bitbang_init(void)
 {
 	bitbang_interface = &remote_bitbang_bitbang;
 
+	remote_bitbang_recv_buf_start = 0;
+	remote_bitbang_recv_buf_end = 0;
+
 	LOG_INFO("Initializing remote_bitbang driver");
-	if (remote_bitbang_port == 0)
-		return remote_bitbang_init_unix();
-	return remote_bitbang_init_tcp();
+	if (!remote_bitbang_port)
+		remote_bitbang_fd = remote_bitbang_init_unix();
+	else
+		remote_bitbang_fd = remote_bitbang_init_tcp();
+
+	if (remote_bitbang_fd < 0)
+		return remote_bitbang_fd;
+
+	socket_nonblock(remote_bitbang_fd);
+
+	LOG_INFO("remote_bitbang driver initialized");
+	return ERROR_OK;
 }
 
 COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_port_command)
 {
 	if (CMD_ARGC == 1) {
-		COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], remote_bitbang_port);
+		uint16_t port;
+		COMMAND_PARSE_NUMBER(u16, CMD_ARGV[0], port);
+		free(remote_bitbang_port);
+		remote_bitbang_port = port == 0 ? NULL : strdup(CMD_ARGV[0]);
 		return ERROR_OK;
 	}
 	return ERROR_COMMAND_SYNTAX_ERROR;
@@ -242,37 +398,92 @@ COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_port_command)
 COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_host_command)
 {
 	if (CMD_ARGC == 1) {
-		strncpy(remote_bitbang_host, CMD_ARGV[0], REMOTE_BITBANG_HOST_MAX);
-		remote_bitbang_host[REMOTE_BITBANG_HOST_MAX-1] = '\0';
+		free(remote_bitbang_host);
+		remote_bitbang_host = strdup(CMD_ARGV[0]);
 		return ERROR_OK;
 	}
 	return ERROR_COMMAND_SYNTAX_ERROR;
 }
 
-static const struct command_registration remote_bitbang_command_handlers[] = {
+static const char * const remote_bitbang_transports[] = { "jtag", "swd", NULL };
+
+COMMAND_HANDLER(remote_bitbang_handle_remote_bitbang_use_remote_sleep_command)
+{
+	if (CMD_ARGC != 1)
+		return ERROR_COMMAND_SYNTAX_ERROR;
+
+	COMMAND_PARSE_ON_OFF(CMD_ARGV[0], use_remote_sleep);
+
+	return ERROR_OK;
+}
+
+static const struct command_registration remote_bitbang_subcommand_handlers[] = {
 	{
-		.name = "remote_bitbang_port",
+		.name = "port",
 		.handler = remote_bitbang_handle_remote_bitbang_port_command,
 		.mode = COMMAND_CONFIG,
 		.help = "Set the port to use to connect to the remote jtag.\n"
-			"  if 0, use unix sockets to connect to the remote jtag.",
+			"  if 0 or unset, use unix sockets to connect to the remote jtag.",
 		.usage = "port_number",
 	},
 	{
-		.name = "remote_bitbang_host",
+		.name = "host",
 		.handler = remote_bitbang_handle_remote_bitbang_host_command,
 		.mode = COMMAND_CONFIG,
 		.help = "Set the host to use to connect to the remote jtag.\n"
-			"  if port is 0, this is the name of the unix socket to use.",
+			"  if port is 0 or unset, this is the name of the unix socket to use.",
 		.usage = "host_name",
 	},
-	COMMAND_REGISTRATION_DONE,
+	{
+		.name = "use_remote_sleep",
+		.handler = remote_bitbang_handle_remote_bitbang_use_remote_sleep_command,
+		.mode = COMMAND_CONFIG,
+		.help = "Rather than executing sleep locally, include delays in the "
+			"instruction stream for the remote host.",
+		.usage = "(on|off)",
+	},
+	COMMAND_REGISTRATION_DONE
 };
 
-struct jtag_interface remote_bitbang_interface = {
+static const struct command_registration remote_bitbang_command_handlers[] = {
+	{
+		.name = "remote_bitbang",
+		.mode = COMMAND_ANY,
+		.help = "perform remote_bitbang management",
+		.chain = remote_bitbang_subcommand_handlers,
+		.usage = "",
+	},
+	COMMAND_REGISTRATION_DONE
+};
+
+static int remote_bitbang_execute_queue(struct jtag_command *cmd_queue)
+{
+	/* safety: the send buffer must be empty, no leftover characters from
+	 * previous transactions */
+	assert(remote_bitbang_send_buf_used == 0);
+
+	/* process the JTAG command queue */
+	int ret = bitbang_execute_queue(cmd_queue);
+	if (ret != ERROR_OK)
+		return ret;
+
+	/* flush not-yet-sent characters, if any */
+	return remote_bitbang_flush();
+}
+
+static struct jtag_interface remote_bitbang_interface = {
+	.execute_queue = &remote_bitbang_execute_queue,
+};
+
+struct adapter_driver remote_bitbang_adapter_driver = {
 	.name = "remote_bitbang",
-	.execute_queue = &bitbang_execute_queue,
+	.transports = remote_bitbang_transports,
 	.commands = remote_bitbang_command_handlers,
+
 	.init = &remote_bitbang_init,
 	.quit = &remote_bitbang_quit,
+	.reset = &remote_bitbang_reset,
+
+	.jtag_ops = &remote_bitbang_interface,
+	.swd_ops = &bitbang_swd,
 };