X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=blobdiff_plain;f=src%2Fjtag%2Fdrivers%2Fjlink.c;h=04297ca07406d1d46eb38c8b074690d85a5a9d1d;hp=9b2326bdb0918a9f3c7614b136bdcf0ea6ccef0c;hb=a6c4eb03455f6e97fc25183aae249d6ccdcbfb0f;hpb=865efd828a267992db0f2a92a731c5ce23a34236

diff --git a/src/jtag/drivers/jlink.c b/src/jtag/drivers/jlink.c
index 9b2326bdb0..04297ca074 100644
--- a/src/jtag/drivers/jlink.c
+++ b/src/jtag/drivers/jlink.c
@@ -5,6 +5,12 @@
  *   Copyright (C) 2008 by Spencer Oliver                                  *
  *   spen@spen-soft.co.uk                                                  *
  *                                                                         *
+ *   Copyright (C) 2011 by Jean-Christophe PLAGNIOL-VIILARD                *
+ *   plagnioj@jcrosoft.com                                                 *
+ *                                                                         *
+ *   Copyright (C) 2015 by Marc Schink                                     *
+ *   openocd-dev@marcschink.de                                             *
+ *                                                                         *
  *   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     *
@@ -18,120 +24,93 @@
  *   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.             *
  ***************************************************************************/
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
-#include "interface.h"
-#include "commands.h"
-#include "usb_common.h"
-
-
-#define VID 0x1366
-#define PID 0x0101
-
-#define JLINK_WRITE_ENDPOINT	0x02
-#define JLINK_READ_ENDPOINT		0x81
-
-static unsigned int jlink_write_ep = JLINK_WRITE_ENDPOINT;
-static unsigned int jlink_read_ep = JLINK_READ_ENDPOINT;
-static unsigned int jlink_hw_jtag_version = 2;
-
-#define JLINK_USB_TIMEOUT		1000
-
-// See Section 1.3.2 of the Segger JLink USB protocol manual
-/* 2048 is the max value we can use here */
-//#define JLINK_TAP_BUFFER_SIZE 2048
-#define JLINK_TAP_BUFFER_SIZE 256
-//#define JLINK_TAP_BUFFER_SIZE 384
-
-#define JLINK_IN_BUFFER_SIZE			2048
-#define JLINK_OUT_BUFFER_SIZE			2*2048 + 4
-#define JLINK_EMU_RESULT_BUFFER_SIZE	64
-
-/* Global USB buffers */
-static uint8_t usb_in_buffer[JLINK_IN_BUFFER_SIZE];
-static uint8_t usb_out_buffer[JLINK_OUT_BUFFER_SIZE];
-static uint8_t usb_emu_result_buffer[JLINK_EMU_RESULT_BUFFER_SIZE];
-
-/* Constants for JLink command */
-#define EMU_CMD_VERSION		0x01
-#define EMU_CMD_SET_SPEED		0x05
-#define EMU_CMD_GET_STATE		0x07
-#define EMU_CMD_HW_CLOCK			0xc8
-#define EMU_CMD_HW_TMS0			0xc9
-#define EMU_CMD_HW_TMS1			0xca
-#define EMU_CMD_HW_JTAG2		0xce
-#define EMU_CMD_HW_JTAG3		0xcf
-#define EMU_CMD_GET_MAX_MEM_BLOCK	0xd4
-#define EMU_CMD_HW_RESET0		0xdc
-#define EMU_CMD_HW_RESET1		0xdd
-#define EMU_CMD_HW_TRST0		0xde
-#define EMU_CMD_HW_TRST1		0xdf
-#define EMU_CMD_GET_CAPS		0xe8
-#define EMU_CMD_GET_HW_VERSION	0xf0
-
-/* bits return from EMU_CMD_GET_CAPS */
-#define EMU_CAP_GET_HW_VERSION		1
-#define EMU_CAP_GET_MAX_BLOCK_SIZE	11
-
-/* max speed 12MHz v5.0 jlink */
-#define JLINK_MAX_SPEED 12000
+#include <stdint.h>
+#include <math.h>
+
+#include <jtag/interface.h>
+#include <jtag/swd.h>
+#include <jtag/commands.h>
+
+#include <libjaylink/libjaylink.h>
+
+static struct jaylink_context *jayctx;
+static struct jaylink_device_handle *devh;
+static struct jaylink_connection conn;
+static struct jaylink_connection connlist[JAYLINK_MAX_CONNECTIONS];
+static enum jaylink_jtag_version jtag_command_version;
+static uint8_t caps[JAYLINK_DEV_EXT_CAPS_SIZE];
+
+static uint32_t serial_number;
+static bool use_serial_number;
+static uint8_t usb_address;
+static bool use_usb_address;
+static uint8_t iface = JAYLINK_TIF_JTAG;
+static bool trace_enabled;
+
+#define JLINK_MAX_SPEED			12000
+#define JLINK_TAP_BUFFER_SIZE	2048
+
+static unsigned int swd_buffer_size = JLINK_TAP_BUFFER_SIZE;
+
+/* 256 byte non-volatile memory */
+struct device_config {
+	uint8_t	usb_address;
+	/* 0ffset 0x01 to 0x03 */
+	uint8_t	reserved_1[3];
+	uint32_t target_power;
+	/* 0ffset 0x08 to 0x1f */
+	uint8_t reserved_2[24];
+	/* IP only for J-Link Pro */
+	uint8_t ip_address[4];
+	uint8_t subnet_mask[4];
+	/* 0ffset 0x28 to 0x2f */
+	uint8_t reserved_3[8];
+	uint8_t mac_address[6];
+	/* 0ffset 0x36 to 0xff */
+	uint8_t reserved_4[202];
+} __attribute__ ((packed));
+
+static struct device_config config;
+static struct device_config tmp_config;
 
 /* Queue command functions */
 static void jlink_end_state(tap_state_t state);
 static void jlink_state_move(void);
 static void jlink_path_move(int num_states, tap_state_t *path);
 static void jlink_runtest(int num_cycles);
-static void jlink_scan(bool ir_scan, enum scan_type type, uint8_t *buffer, int scan_size, struct scan_command *command);
+static void jlink_scan(bool ir_scan, enum scan_type type, uint8_t *buffer,
+		int scan_size, struct scan_command *command);
 static void jlink_reset(int trst, int srst);
-static void jlink_simple_command(uint8_t command);
-static int jlink_get_status(void);
+static int jlink_swd_run_queue(void);
+static void jlink_swd_queue_cmd(uint8_t cmd, uint32_t *dst, uint32_t data, uint32_t ap_delay_clk);
+static int jlink_swd_switch_seq(enum swd_special_seq seq);
 
 /* J-Link tap buffer functions */
 static void jlink_tap_init(void);
 static int jlink_tap_execute(void);
 static void jlink_tap_ensure_space(int scans, int bits);
 static void jlink_tap_append_step(int tms, int tdi);
-static void jlink_tap_append_scan(int length, uint8_t *buffer, struct scan_command *command);
-
-/* Jlink lowlevel functions */
-struct jlink {
-	struct usb_dev_handle* usb_handle;
-};
-
-static struct jlink *jlink_usb_open(void);
-static void jlink_usb_close(struct jlink *jlink);
-static int jlink_usb_message(struct jlink *jlink, int out_length, int in_length);
-static int jlink_usb_write(struct jlink *jlink, int out_length);
-static int jlink_usb_read(struct jlink *jlink, int expected_size);
-static int jlink_usb_read_emu_result(struct jlink *jlink);
-
-/* helper functions */
-static int jlink_get_version_info(void);
-
-#ifdef _DEBUG_USB_COMMS_
-static void jlink_debug_buffer(uint8_t *buffer, int length);
-#endif
+static void jlink_tap_append_scan(int length, uint8_t *buffer,
+		struct scan_command *command);
 
 static enum tap_state jlink_last_state = TAP_RESET;
-
-static struct jlink* jlink_handle;
+static int queued_retval;
 
 /***************************************************************************/
 /* External interface implementation */
 
 static void jlink_execute_runtest(struct jtag_command *cmd)
 {
-	DEBUG_JTAG_IO("runtest %i cycles, end in %i",
-			cmd->cmd.runtest->num_cycles,
-			cmd->cmd.runtest->end_state);
+	DEBUG_JTAG_IO("runtest %i cycles, end in %i", cmd->cmd.runtest->num_cycles,
+		cmd->cmd.runtest->end_state);
 
 	jlink_end_state(cmd->cmd.runtest->end_state);
-
 	jlink_runtest(cmd->cmd.runtest->num_cycles);
 }
 
@@ -149,8 +128,7 @@ static void jlink_execute_pathmove(struct jtag_command *cmd)
 		cmd->cmd.pathmove->num_states,
 		cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]);
 
-	jlink_path_move(cmd->cmd.pathmove->num_states,
-			cmd->cmd.pathmove->path);
+	jlink_path_move(cmd->cmd.pathmove->num_states, cmd->cmd.pathmove->path);
 }
 
 static void jlink_execute_scan(struct jtag_command *cmd)
@@ -166,18 +144,14 @@ static void jlink_execute_scan(struct jtag_command *cmd)
 	scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
 	DEBUG_JTAG_IO("scan input, length = %d", scan_size);
 
-#ifdef _DEBUG_USB_COMMS_
-	jlink_debug_buffer(buffer, (scan_size + 7) / 8);
-#endif
 	type = jtag_scan_type(cmd->cmd.scan);
-	jlink_scan(cmd->cmd.scan->ir_scan,
-			type, buffer, scan_size, cmd->cmd.scan);
+	jlink_scan(cmd->cmd.scan->ir_scan, type, buffer, scan_size, cmd->cmd.scan);
 }
 
 static void jlink_execute_reset(struct jtag_command *cmd)
 {
-	DEBUG_JTAG_IO("reset trst: %i srst %i",
-			cmd->cmd.reset->trst, cmd->cmd.reset->srst);
+	DEBUG_JTAG_IO("reset trst: %i srst %i", cmd->cmd.reset->trst,
+		cmd->cmd.reset->srst);
 
 	jlink_tap_execute();
 	jlink_reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
@@ -186,71 +160,104 @@ static void jlink_execute_reset(struct jtag_command *cmd)
 
 static void jlink_execute_sleep(struct jtag_command *cmd)
 {
-	DEBUG_JTAG_IO("sleep %i", cmd->cmd.sleep->us);
+	DEBUG_JTAG_IO("sleep %" PRIi32 "", cmd->cmd.sleep->us);
 	jlink_tap_execute();
 	jtag_sleep(cmd->cmd.sleep->us);
 }
 
-static void jlink_execute_command(struct jtag_command *cmd)
+static int jlink_execute_command(struct jtag_command *cmd)
 {
-	switch (cmd->type)
-	{
-	case JTAG_RUNTEST:   jlink_execute_runtest(cmd); break;
-	case JTAG_STATEMOVE: jlink_execute_statemove(cmd); break;
-	case JTAG_PATHMOVE:  jlink_execute_pathmove(cmd); break;
-	case JTAG_SCAN:      jlink_execute_scan(cmd); break;
-	case JTAG_RESET:     jlink_execute_reset(cmd); break;
-	case JTAG_SLEEP:     jlink_execute_sleep(cmd); break;
-	default:
-		LOG_ERROR("BUG: unknown JTAG command type encountered");
-		exit(-1);
+	switch (cmd->type) {
+		case JTAG_RUNTEST:
+			jlink_execute_runtest(cmd);
+			break;
+		case JTAG_TLR_RESET:
+			jlink_execute_statemove(cmd);
+			break;
+		case JTAG_PATHMOVE:
+			jlink_execute_pathmove(cmd);
+			break;
+		case JTAG_SCAN:
+			jlink_execute_scan(cmd);
+			break;
+		case JTAG_RESET:
+			jlink_execute_reset(cmd);
+			break;
+		case JTAG_SLEEP:
+			jlink_execute_sleep(cmd);
+			break;
+		default:
+			LOG_ERROR("BUG: Unknown JTAG command type encountered.");
+			return ERROR_JTAG_QUEUE_FAILED;
 	}
+
+	return ERROR_OK;
 }
 
 static int jlink_execute_queue(void)
 {
+	int ret;
 	struct jtag_command *cmd = jtag_command_queue;
 
-	while (cmd != NULL)
-	{
-		jlink_execute_command(cmd);
+	while (cmd != NULL) {
+		ret = jlink_execute_command(cmd);
+
+		if (ret != ERROR_OK)
+			return ret;
+
 		cmd = cmd->next;
 	}
 
 	return jlink_tap_execute();
 }
 
-/* Sets speed in kHz. */
 static int jlink_speed(int speed)
 {
-	int result;
+	int ret;
+	uint32_t freq;
+	uint16_t div;
+	int max_speed;
 
-	if (speed > JLINK_MAX_SPEED)
-	{
-		LOG_INFO("Ignoring speed request: %dkHz exceeds %dkHz maximum",
-				speed, JLINK_MAX_SPEED);
-		return ERROR_OK;
+	if (jaylink_has_cap(caps, JAYLINK_DEV_CAP_GET_SPEEDS)) {
+		ret = jaylink_get_speeds(devh, &freq, &div);
+
+		if (ret != JAYLINK_OK) {
+			LOG_ERROR("jaylink_get_speeds() failed: %s.",
+				jaylink_strerror_name(ret));
+			return ERROR_JTAG_DEVICE_ERROR;
+		}
+
+		freq = freq / 1000;
+		max_speed = freq / div;
+	} else {
+		max_speed = JLINK_MAX_SPEED;
 	}
 
-	/* check for RTCK setting */
-	if (speed == 0)
-		speed = -1;
+	if (!speed) {
+		if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_ADAPTIVE_CLOCKING)) {
+			LOG_ERROR("Adaptive clocking is not supported by the device.");
+			return ERROR_JTAG_NOT_IMPLEMENTED;
+		}
+
+		speed = JAYLINK_SPEED_ADAPTIVE_CLOCKING;
+	} else if (speed > max_speed) {
+		LOG_INFO("Reduced speed from %d kHz to %d kHz (maximum).", speed,
+			max_speed);
+		speed = max_speed;
+	}
 
-	usb_out_buffer[0] = EMU_CMD_SET_SPEED;
-	usb_out_buffer[1] = (speed >> 0) & 0xff;
-	usb_out_buffer[2] = (speed >> 8) & 0xff;
+	ret = jaylink_set_speed(devh, speed);
 
-	result = jlink_usb_write(jlink_handle, 3);
-	if (result != 3)
-	{
-		LOG_ERROR("J-Link setting speed failed (%d)", result);
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_set_speed() failed: %s.",
+			jaylink_strerror_name(ret));
 		return ERROR_JTAG_DEVICE_ERROR;
 	}
 
 	return ERROR_OK;
 }
 
-static int jlink_speed_div(int speed, int* khz)
+static int jlink_speed_div(int speed, int *khz)
 {
 	*khz = speed;
 
@@ -264,61 +271,364 @@ static int jlink_khz(int khz, int *jtag_speed)
 	return ERROR_OK;
 }
 
-static int jlink_init(void)
+static bool read_device_config(struct device_config *cfg)
+{
+	int ret;
+
+	ret = jaylink_read_raw_config(devh, (uint8_t *)cfg);
+
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_read_raw_config() failed: %s.",
+			jaylink_strerror_name(ret));
+		return false;
+	}
+
+	if (cfg->usb_address == 0xff)
+		cfg->usb_address = 0x00;
+
+	if (cfg->target_power == 0xffffffff)
+		cfg->target_power = 0;
+
+	return true;
+}
+
+static int select_interface(void)
+{
+	int ret;
+	uint32_t interfaces;
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_SELECT_TIF)) {
+		if (iface != JAYLINK_TIF_JTAG) {
+			LOG_ERROR("Device supports JTAG transport only.");
+			return ERROR_JTAG_INIT_FAILED;
+		}
+
+		return ERROR_OK;
+	}
+
+	ret = jaylink_get_available_interfaces(devh, &interfaces);
+
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_get_available_interfaces() failed: %s.",
+			jaylink_strerror_name(ret));
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	if (!(interfaces & (1 << iface))) {
+		LOG_ERROR("Selected transport is not supported by the device.");
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	ret = jaylink_select_interface(devh, iface);
+
+	if (ret < 0) {
+		LOG_ERROR("jaylink_select_interface() failed: %s.",
+			jaylink_strerror_name(ret));
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	return ERROR_OK;
+}
+
+static int jlink_register(void)
 {
+	int ret;
 	int i;
+	bool handle_found;
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_REGISTER))
+		return ERROR_OK;
 
-	jlink_handle = jlink_usb_open();
+	ret = jaylink_register(devh, &conn, connlist, NULL, NULL);
 
-	if (jlink_handle == 0)
-	{
-		LOG_ERROR("Cannot find jlink Interface! Please check connection and permissions.");
+	if (ret < 0) {
+		LOG_ERROR("jaylink_register() failed: %s.",
+			jaylink_strerror_name(ret));
+		return ERROR_FAIL;
+	}
+
+	handle_found = false;
+
+	for (i = 0; i < ret; i++) {
+		if (connlist[i].handle == conn.handle) {
+			handle_found = true;
+			break;
+		}
+	}
+
+	if (!handle_found) {
+		LOG_ERROR("Registration failed: maximum number of connections on the "
+			"device reached.");
+		return ERROR_FAIL;
+	}
+
+	return ERROR_OK;
+}
+
+/*
+ * Adjust the SWD transaction buffer size depending on the free device internal
+ * memory. This ensures that the SWD transactions sent to the device do not
+ * exceed the internal memory of the device.
+ */
+static bool adjust_swd_buffer_size(void)
+{
+	int ret;
+	uint32_t tmp;
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_GET_FREE_MEMORY))
+		return true;
+
+	ret = jaylink_get_free_memory(devh, &tmp);
+
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_get_free_memory() failed: %s.",
+			jaylink_strerror_name(ret));
+		return false;
+	}
+
+	if (tmp < 143) {
+		LOG_ERROR("Not enough free device internal memory: %u bytes.", tmp);
+		return false;
+	}
+
+	tmp = MIN(JLINK_TAP_BUFFER_SIZE, (tmp - 16) / 2);
+
+	if (tmp != swd_buffer_size) {
+		swd_buffer_size = tmp;
+		LOG_DEBUG("Adjusted SWD transaction buffer size to %u bytes.",
+			swd_buffer_size);
+	}
+
+	return true;
+}
+
+static int jlink_init(void)
+{
+	int ret;
+	struct jaylink_device **devs;
+	unsigned int i;
+	bool found_device;
+	uint32_t tmp;
+	char *firmware_version;
+	struct jaylink_hardware_version hwver;
+	struct jaylink_hardware_status hwstatus;
+
+	ret = jaylink_init(&jayctx);
+
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_init() failed: %s.",
+			jaylink_strerror_name(ret));
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	ret = jaylink_get_device_list(jayctx, &devs);
+
+	if (ret < 0) {
+		LOG_ERROR("jaylink_get_device_list() failed: %s.",
+			jaylink_strerror_name(ret));
+		jaylink_exit(jayctx);
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	found_device = false;
+
+	if (!use_serial_number && !use_usb_address)
+		LOG_INFO("No device selected, using first device.");
+
+	for (i = 0; devs[i]; i++) {
+		jaylink_device_get_serial_number(devs[i], &tmp);
+		ret = jaylink_device_get_usb_address(devs[i]);
+
+		if (use_usb_address && usb_address != ret)
+			continue;
+
+		if (use_serial_number && tmp != serial_number)
+			continue;
+
+		ret = jaylink_open(devs[i], &devh);
+
+		if (ret != JAYLINK_OK) {
+			LOG_ERROR("Failed to open device: %s.", jaylink_strerror_name(ret));
+			continue;
+		}
+
+		found_device = true;
+		break;
+	}
+
+	jaylink_free_device_list(devs, 1);
+
+	if (!found_device) {
+		LOG_ERROR("No J-Link device found.");
+		jaylink_exit(jayctx);
 		return ERROR_JTAG_INIT_FAILED;
 	}
 
 	/*
-	 *  The next three instructions were added after discovering a problem while using an oscilloscope.  For the V8
-	 *	SAM-ICE dongle (and likely other j-link device variants), the reset line to the target microprocessor was found to
-	 *	cycle only intermittently during emulator startup (even after encountering the downstream reset instruction later
-	 *	in the code).  This was found to create two issues:  1) In general it is a bad practice to not reset a CPU to a known
-	 *	state when starting an emulator and 2) something critical happens inside the dongle when it does the first read
-	 *	following a new USB session.  Keeping the processor in reset during the first read collecting version information
-	 *	seems to prevent errant "J-Link command EMU_CMD_VERSION failed" issues.
+	 * Be careful with changing the following initialization sequence because
+	 * some devices are known to be sensitive regarding the order.
 	 */
 
-	LOG_INFO("J-Link initialization started / target CPU reset initiated");
-	jlink_simple_command(EMU_CMD_HW_TRST0);
-	jlink_simple_command(EMU_CMD_HW_RESET0);
-	usleep(1000);
+	ret = jaylink_get_firmware_version(devh, &firmware_version);
+
+	if (ret > 0) {
+		LOG_INFO("%s", firmware_version);
+		free(firmware_version);
+	} else if (!ret) {
+		LOG_WARNING("Device responds empty firmware version string.");
+	} else {
+		LOG_ERROR("jaylink_get_firmware_version() failed: %s.",
+			jaylink_strerror_name(ret));
+		jaylink_close(devh);
+		jaylink_exit(jayctx);
+		return ERROR_JTAG_INIT_FAILED;
+	}
 
-	jlink_hw_jtag_version = 2;
+	memset(caps, 0, JAYLINK_DEV_EXT_CAPS_SIZE);
+	ret = jaylink_get_caps(devh, caps);
 
-	if (jlink_get_version_info() == ERROR_OK)
-	{
-		/* attempt to get status */
-		jlink_get_status();
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_get_caps() failed: %s.", jaylink_strerror_name(ret));
+		jaylink_close(devh);
+		jaylink_exit(jayctx);
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	if (jaylink_has_cap(caps, JAYLINK_DEV_CAP_GET_EXT_CAPS)) {
+		ret = jaylink_get_extended_caps(devh, caps);
+
+		if (ret != JAYLINK_OK) {
+			LOG_ERROR("jaylink_get_extended_caps() failed:  %s.",
+				jaylink_strerror_name(ret));
+			jaylink_close(devh);
+			jaylink_exit(jayctx);
+			return ERROR_JTAG_INIT_FAILED;
+		}
+	}
+
+	jtag_command_version = JAYLINK_JTAG_V2;
+
+	if (jaylink_has_cap(caps, JAYLINK_DEV_CAP_GET_HW_VERSION)) {
+		ret = jaylink_get_hardware_version(devh, &hwver);
+
+		if (ret != JAYLINK_OK) {
+			LOG_ERROR("Failed to retrieve hardware version: %s.",
+				jaylink_strerror_name(ret));
+			jaylink_close(devh);
+			jaylink_exit(jayctx);
+			return ERROR_JTAG_INIT_FAILED;
+		}
+
+		LOG_INFO("Hardware version: %u.%02u", hwver.major, hwver.minor);
+
+		if (hwver.major >= 5)
+			jtag_command_version = JAYLINK_JTAG_V3;
+	}
+
+	if (iface == JAYLINK_TIF_SWD) {
+		/*
+		 * Adjust the SWD transaction buffer size in case there is already
+		 * allocated memory on the device. This happens for example if the
+		 * memory for SWO capturing is still allocated because the software
+		 * which used the device before has not been shut down properly.
+		 */
+		if (!adjust_swd_buffer_size()) {
+			jaylink_close(devh);
+			jaylink_exit(jayctx);
+			return ERROR_JTAG_INIT_FAILED;
+		}
+	}
+
+	if (jaylink_has_cap(caps, JAYLINK_DEV_CAP_READ_CONFIG)) {
+		if (!read_device_config(&config)) {
+			LOG_ERROR("Failed to read device configuration data.");
+			jaylink_close(devh);
+			jaylink_exit(jayctx);
+			return ERROR_JTAG_INIT_FAILED;
+		}
+
+		memcpy(&tmp_config, &config, sizeof(struct device_config));
+	}
+
+	ret = jaylink_get_hardware_status(devh, &hwstatus);
+
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_get_hardware_status() failed: %s.",
+			jaylink_strerror_name(ret));
+		jaylink_close(devh);
+		jaylink_exit(jayctx);
+		return ERROR_JTAG_INIT_FAILED;
+	}
+
+	LOG_INFO("VTarget = %u.%03u V", hwstatus.target_voltage / 1000,
+		hwstatus.target_voltage % 1000);
+
+	conn.handle = 0;
+	conn.pid = 0;
+	conn.hid = 0;
+	conn.iid = 0;
+	conn.cid = 0;
+
+	ret = jlink_register();
+
+	if (ret != ERROR_OK) {
+		jaylink_close(devh);
+		jaylink_exit(jayctx);
+		return ERROR_JTAG_INIT_FAILED;
 	}
 
-	LOG_INFO("J-Link JTAG Interface ready");
+	ret = select_interface();
+
+	if (ret != ERROR_OK) {
+		jaylink_close(devh);
+		jaylink_exit(jayctx);
+		return ret;
+	}
 
 	jlink_reset(0, 0);
 	jtag_sleep(3000);
 	jlink_tap_init();
-	jlink_speed(jtag_get_speed());
 
-	/* v5/6 jlink seems to have an issue if the first tap move
-	 * is not divisible by 8, so we send a TLR on first power up */
-	for (i = 0; i < 8; i++) {
-		jlink_tap_append_step(1, 0);
+	jlink_speed(jtag_get_speed_khz());
+
+	if (iface == JAYLINK_TIF_JTAG) {
+		/*
+		 * J-Link devices with firmware version v5 and v6 seems to have an issue
+		 * if the first tap move is not divisible by 8, so we send a TLR on
+		 * first power up.
+		 */
+		for (i = 0; i < 8; i++)
+			jlink_tap_append_step(1, 0);
+
+		jlink_tap_execute();
 	}
-	jlink_tap_execute();
 
 	return ERROR_OK;
 }
 
 static int jlink_quit(void)
 {
-	jlink_usb_close(jlink_handle);
+	int ret;
+
+	if (trace_enabled) {
+		ret = jaylink_swo_stop(devh);
+
+		if (ret != JAYLINK_OK)
+			LOG_ERROR("jaylink_swo_stop() failed: %s.",
+				jaylink_strerror_name(ret));
+	}
+
+	if (jaylink_has_cap(caps, JAYLINK_DEV_CAP_REGISTER)) {
+		ret = jaylink_unregister(devh, &conn, connlist, NULL, NULL);
+
+		if (ret < 0)
+			LOG_ERROR("jaylink_unregister() failed: %s.",
+				jaylink_strerror_name(ret));
+	}
+
+	jaylink_close(devh);
+	jaylink_exit(jayctx);
+
 	return ERROR_OK;
 }
 
@@ -328,11 +638,8 @@ static int jlink_quit(void)
 static void jlink_end_state(tap_state_t state)
 {
 	if (tap_is_state_stable(state))
-	{
 		tap_set_end_state(state);
-	}
-	else
-	{
+	else {
 		LOG_ERROR("BUG: %i is not a valid end state", state);
 		exit(-1);
 	}
@@ -343,11 +650,13 @@ static void jlink_state_move(void)
 {
 	int i;
 	int tms = 0;
-	uint8_t tms_scan = tap_get_tms_path(tap_get_state(), tap_get_end_state());
-	uint8_t tms_scan_bits = tap_get_tms_path_len(tap_get_state(), tap_get_end_state());
+	uint8_t tms_scan;
+	uint8_t tms_scan_bits;
 
-	for (i = 0; i < tms_scan_bits; i++)
-	{
+	tms_scan = tap_get_tms_path(tap_get_state(), tap_get_end_state());
+	tms_scan_bits = tap_get_tms_path_len(tap_get_state(), tap_get_end_state());
+
+	for (i = 0; i < tms_scan_bits; i++) {
 		tms = (tms_scan >> i) & 1;
 		jlink_tap_append_step(tms, 0);
 	}
@@ -359,19 +668,14 @@ static void jlink_path_move(int num_states, tap_state_t *path)
 {
 	int i;
 
-	for (i = 0; i < num_states; i++)
-	{
+	for (i = 0; i < num_states; i++) {
 		if (path[i] == tap_state_transition(tap_get_state(), false))
-		{
 			jlink_tap_append_step(0, 0);
-		}
 		else if (path[i] == tap_state_transition(tap_get_state(), true))
-		{
 			jlink_tap_append_step(1, 0);
-		}
-		else
-		{
-			LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition", tap_state_name(tap_get_state()), tap_state_name(path[i]));
+		else {
+			LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition.",
+				tap_state_name(tap_get_state()), tap_state_name(path[i]));
 			exit(-1);
 		}
 
@@ -387,31 +691,28 @@ static void jlink_runtest(int num_cycles)
 
 	tap_state_t saved_end_state = tap_get_end_state();
 
-	jlink_tap_ensure_space(1,num_cycles + 16);
+	jlink_tap_ensure_space(1, num_cycles + 16);
 
-	/* only do a state_move when we're not already in IDLE */
-	if (tap_get_state() != TAP_IDLE)
-	{
+	/* Only do a state_move when we're not already in IDLE. */
+	if (tap_get_state() != TAP_IDLE) {
 		jlink_end_state(TAP_IDLE);
 		jlink_state_move();
-//		num_cycles--;
+		/* num_cycles--; */
 	}
 
-	/* execute num_cycles */
+	/* Execute num_cycles. */
 	for (i = 0; i < num_cycles; i++)
-	{
 		jlink_tap_append_step(0, 0);
-	}
 
-	/* finish in end_state */
+	/* Finish in end_state. */
 	jlink_end_state(saved_end_state);
+
 	if (tap_get_state() != tap_get_end_state())
-	{
 		jlink_state_move();
-	}
 }
 
-static void jlink_scan(bool ir_scan, enum scan_type type, uint8_t *buffer, int scan_size, struct scan_command *command)
+static void jlink_scan(bool ir_scan, enum scan_type type, uint8_t *buffer,
+		int scan_size, struct scan_command *command)
 {
 	tap_state_t saved_end_state;
 
@@ -419,259 +720,886 @@ static void jlink_scan(bool ir_scan, enum scan_type type, uint8_t *buffer, int s
 
 	saved_end_state = tap_get_end_state();
 
-	/* Move to appropriate scan state */
+	/* Move to appropriate scan state. */
 	jlink_end_state(ir_scan ? TAP_IRSHIFT : TAP_DRSHIFT);
 
-	/* Only move if we're not already there */
+	/* Only move if we're not already there. */
 	if (tap_get_state() != tap_get_end_state())
 		jlink_state_move();
 
 	jlink_end_state(saved_end_state);
 
-	/* Scan */
+	/* Scan. */
 	jlink_tap_append_scan(scan_size, buffer, command);
 
-	/* We are in Exit1, go to Pause */
+	/* We are in Exit1, go to Pause. */
 	jlink_tap_append_step(0, 0);
 
 	tap_set_state(ir_scan ? TAP_IRPAUSE : TAP_DRPAUSE);
 
 	if (tap_get_state() != tap_get_end_state())
-	{
 		jlink_state_move();
-	}
 }
 
 static void jlink_reset(int trst, int srst)
 {
-	LOG_DEBUG("trst: %i, srst: %i", trst, srst);
+	LOG_DEBUG("TRST: %i, SRST: %i.", trst, srst);
 
-	/* Signals are active low */
+	/* Signals are active low. */
 	if (srst == 0)
-	{
-		jlink_simple_command(EMU_CMD_HW_RESET1);
-	}
+		jaylink_set_reset(devh);
+
 	if (srst == 1)
-	{
-		jlink_simple_command(EMU_CMD_HW_RESET0);
-	}
+		jaylink_clear_reset(devh);
 
 	if (trst == 1)
-	{
-		jlink_simple_command(EMU_CMD_HW_TRST0);
-	}
+		jaylink_jtag_clear_trst(devh);
 
 	if (trst == 0)
-	{
-		jlink_simple_command(EMU_CMD_HW_TRST1);
-	}
+		jaylink_jtag_set_trst(devh);
 }
 
-static void jlink_simple_command(uint8_t command)
+COMMAND_HANDLER(jlink_usb_command)
 {
-	int result;
-
-	DEBUG_JTAG_IO("0x%02x", command);
+	if (CMD_ARGC != 1) {
+		command_print(CMD_CTX, "Need exactly one argument for jlink usb.");
+		return ERROR_COMMAND_SYNTAX_ERROR;
+	}
 
-	usb_out_buffer[0] = command;
-	result = jlink_usb_write(jlink_handle, 1);
+	if (sscanf(CMD_ARGV[0], "%" SCNd8, &usb_address) != 1) {
+		command_print(CMD_CTX, "Invalid USB address: %s.", CMD_ARGV[0]);
+		return ERROR_FAIL;
+	}
 
-	if (result != 1)
-	{
-		LOG_ERROR("J-Link command 0x%02x failed (%d)", command, result);
+	if (usb_address > JAYLINK_USB_ADDRESS_3) {
+		command_print(CMD_CTX, "Invalid USB address: %s.", CMD_ARGV[0]);
+		return ERROR_FAIL;
 	}
-}
 
-static int jlink_get_status(void)
-{
-	int result;
+	use_serial_number = false;
+	use_usb_address = true;
 
-	jlink_simple_command(EMU_CMD_GET_STATE);
+	return ERROR_OK;
+}
 
-	result = jlink_usb_read(jlink_handle, 8);
-	if (result != 8)
-	{
-		LOG_ERROR("J-Link command EMU_CMD_GET_STATE failed (%d)\n", result);
-		return ERROR_JTAG_DEVICE_ERROR;
+COMMAND_HANDLER(jlink_serial_command)
+{
+	if (CMD_ARGC != 1) {
+		command_print(CMD_CTX, "Need exactly one argument for jlink serial.");
+		return ERROR_COMMAND_SYNTAX_ERROR;
 	}
 
-	int vref = usb_in_buffer[0] + (usb_in_buffer[1] << 8);
-	LOG_INFO("Vref = %d.%d TCK = %d TDI = %d TDO = %d TMS = %d SRST = %d TRST = %d\n", \
-		vref / 1000, vref % 1000, \
-		usb_in_buffer[2], usb_in_buffer[3], usb_in_buffer[4], \
-		usb_in_buffer[5], usb_in_buffer[6], usb_in_buffer[7]);
+	if (sscanf(CMD_ARGV[0], "%" SCNd32, &serial_number) != 1) {
+		command_print(CMD_CTX, "Invalid serial number: %s.", CMD_ARGV[0]);
+		return ERROR_FAIL;
+	}
 
-	if (vref < 1500)
-		LOG_ERROR("Vref too low. Check Target Power\n");
+	use_serial_number = true;
+	use_usb_address = false;
 
 	return ERROR_OK;
 }
 
-static int jlink_get_version_info(void)
+COMMAND_HANDLER(jlink_handle_hwstatus_command)
 {
-	int result;
-	int len;
-	uint32_t jlink_caps, jlink_max_size;
+	int ret;
+	struct jaylink_hardware_status status;
 
-	/* query hardware version */
-	jlink_simple_command(EMU_CMD_VERSION);
+	ret = jaylink_get_hardware_status(devh, &status);
 
-	result = jlink_usb_read(jlink_handle, 2);
-	if (2 != result)
-	{
-		LOG_ERROR("J-Link command EMU_CMD_VERSION failed (%d)\n", result);
-		return ERROR_JTAG_DEVICE_ERROR;
+	if (ret != JAYLINK_OK) {
+		command_print(CMD_CTX, "jaylink_get_hardware_status() failed: %s.",
+			jaylink_strerror_name(ret));
+		return ERROR_FAIL;
 	}
 
-	len = buf_get_u32(usb_in_buffer, 0, 16);
-	if (len > JLINK_IN_BUFFER_SIZE)
-	{
-		LOG_ERROR("J-Link command EMU_CMD_VERSION impossible return length 0x%0x", len);
-		len = JLINK_IN_BUFFER_SIZE;
-	}
+	command_print(CMD_CTX, "VTarget = %u.%03u V",
+		status.target_voltage / 1000, status.target_voltage % 1000);
 
-	result = jlink_usb_read(jlink_handle, len);
-	if (result != len)
-	{
-		LOG_ERROR("J-Link command EMU_CMD_VERSION failed (%d)\n", result);
-		return ERROR_JTAG_DEVICE_ERROR;
-	}
+	command_print(CMD_CTX, "TCK = %u TDI = %u TDO = %u TMS = %u SRST = %u "
+		"TRST = %u", status.tck, status.tdi, status.tdo, status.tms,
+		status.tres, status.trst);
 
-	usb_in_buffer[result] = 0;
-	LOG_INFO("%s", (char *)usb_in_buffer);
+	if (status.target_voltage < 1500)
+		command_print(CMD_CTX, "Target voltage too low. Check target power.");
 
-	/* query hardware capabilities */
-	jlink_simple_command(EMU_CMD_GET_CAPS);
+	return ERROR_OK;
+}
 
-	result = jlink_usb_read(jlink_handle, 4);
-	if (4 != result)
-	{
-		LOG_ERROR("J-Link command EMU_CMD_GET_CAPS failed (%d)\n", result);
-		return ERROR_JTAG_DEVICE_ERROR;
-	}
+COMMAND_HANDLER(jlink_handle_free_memory_command)
+{
+	int ret;
+	uint32_t tmp;
 
-	jlink_caps = buf_get_u32(usb_in_buffer, 0, 32);
-	LOG_INFO("JLink caps 0x%x", (unsigned)jlink_caps);
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_GET_FREE_MEMORY)) {
+		command_print(CMD_CTX, "Retrieval of free memory is not supported by "
+			"the device.");
+		return ERROR_OK;
+	}
 
-	if (jlink_caps & (1 << EMU_CAP_GET_HW_VERSION))
-	{
-		/* query hardware version */
-		jlink_simple_command(EMU_CMD_GET_HW_VERSION);
+	ret = jaylink_get_free_memory(devh, &tmp);
 
-		result = jlink_usb_read(jlink_handle, 4);
-		if (4 != result)
-		{
-			LOG_ERROR("J-Link command EMU_CMD_GET_HW_VERSION failed (%d)\n", result);
-			return ERROR_JTAG_DEVICE_ERROR;
-		}
+	if (ret != JAYLINK_OK) {
+		command_print(CMD_CTX, "jaylink_get_free_memory() failed: %s.",
+			jaylink_strerror_name(ret));
+		return ERROR_FAIL;
+	}
 
-		uint32_t jlink_hw_version = buf_get_u32(usb_in_buffer, 0, 32);
-		uint32_t major_revision = (jlink_hw_version / 10000) % 100;
-		if (major_revision >= 5)
-			jlink_hw_jtag_version = 3;
+	command_print(CMD_CTX, "Device has %u bytes of free memory.", tmp);
 
-		LOG_INFO("JLink hw version %i", (int)jlink_hw_version);
-	}
+	return ERROR_OK;
+}
 
-	if (jlink_caps & (1 << EMU_CAP_GET_MAX_BLOCK_SIZE))
-	{
-		/* query hardware maximum memory block */
-		jlink_simple_command(EMU_CMD_GET_MAX_MEM_BLOCK);
+COMMAND_HANDLER(jlink_handle_jlink_jtag_command)
+{
+	int tmp;
+	int version;
+
+	if (!CMD_ARGC) {
+		switch (jtag_command_version) {
+			case JAYLINK_JTAG_V2:
+				version = 2;
+				break;
+			case JAYLINK_JTAG_V3:
+				version = 3;
+				break;
+			default:
+				return ERROR_FAIL;
+		}
 
-		result = jlink_usb_read(jlink_handle, 4);
-		if (4 != result)
-		{
-			LOG_ERROR("J-Link command EMU_CMD_GET_MAX_MEM_BLOCK failed (%d)\n", result);
-			return ERROR_JTAG_DEVICE_ERROR;
+		command_print(CMD_CTX, "JTAG command version: %i", version);
+	} else if (CMD_ARGC == 1) {
+		if (sscanf(CMD_ARGV[0], "%i", &tmp) != 1) {
+			command_print(CMD_CTX, "Invalid argument: %s.", CMD_ARGV[0]);
+			return ERROR_COMMAND_SYNTAX_ERROR;
 		}
 
-		jlink_max_size = buf_get_u32(usb_in_buffer, 0, 32);
-		LOG_INFO("JLink max mem block %i", (int)jlink_max_size);
+		switch (tmp) {
+			case 2:
+				jtag_command_version = JAYLINK_JTAG_V2;
+				break;
+			case 3:
+				jtag_command_version = JAYLINK_JTAG_V3;
+				break;
+			default:
+				command_print(CMD_CTX, "Invalid argument: %s.", CMD_ARGV[0]);
+				return ERROR_COMMAND_SYNTAX_ERROR;
+		}
+	} else {
+		command_print(CMD_CTX, "Need exactly one argument for jlink jtag.");
+		return ERROR_COMMAND_SYNTAX_ERROR;
 	}
 
 	return ERROR_OK;
 }
 
-COMMAND_HANDLER(jlink_handle_jlink_info_command)
+COMMAND_HANDLER(jlink_handle_target_power_command)
 {
-	if (jlink_get_version_info() == ERROR_OK)
-	{
-		/* attempt to get status */
-		jlink_get_status();
+	int ret;
+	int enable;
+
+	if (CMD_ARGC != 1) {
+		command_print(CMD_CTX, "Need exactly one argument for jlink "
+			"targetpower.");
+		return ERROR_COMMAND_SYNTAX_ERROR;
 	}
 
-	return ERROR_OK;
-}
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_SET_TARGET_POWER)) {
+		command_print(CMD_CTX, "Target power supply is not supported by the "
+			"device.");
+		return ERROR_OK;
+	}
 
-COMMAND_HANDLER(jlink_handle_jlink_hw_jtag_command)
-{
-	switch (CMD_ARGC) {
-	case 0:
-		command_print(CMD_CTX, "jlink hw jtag  %i", jlink_hw_jtag_version);
-		break;
-	case 1: {
-		int request_version = atoi(CMD_ARGV[0]);
-		switch (request_version) {
-		case 2: case 3:
-			jlink_hw_jtag_version = request_version;
-			break;
-		default:
-			return ERROR_COMMAND_SYNTAX_ERROR;
-		}
-		break;
+	if (!strcmp(CMD_ARGV[0], "on")) {
+		enable = true;
+	} else if (!strcmp(CMD_ARGV[0], "off")) {
+		enable = false;
+	} else {
+		command_print(CMD_CTX, "Invalid argument: %s.", CMD_ARGV[0]);
+		return ERROR_FAIL;
 	}
-	default:
-		return ERROR_COMMAND_SYNTAX_ERROR;
+
+	ret = jaylink_set_target_power(devh, enable);
+
+	if (ret != JAYLINK_OK) {
+		command_print(CMD_CTX, "jaylink_set_target_power() failed: %s.",
+			jaylink_strerror_name(ret));
+		return ERROR_FAIL;
 	}
 
 	return ERROR_OK;
 }
 
-static const struct command_registration jlink_command_handlers[] = {
-	{
-		.name = "jlink_info",
-		.handler = &jlink_handle_jlink_info_command,
-		.mode = COMMAND_EXEC,
-		.help = "show jlink info",
-	},
-	{
-		.name = "jlink_hw_jtag",
-		.handler = &jlink_handle_jlink_hw_jtag_command,
-		.mode = COMMAND_EXEC,
-		.help = "access J-Link HW JTAG command version",
-		.usage = "[2|3]",
+static void show_config_usb_address(struct command_context *ctx)
+{
+	if (config.usb_address != tmp_config.usb_address)
+		command_print(ctx, "USB address: %u [%u]", config.usb_address,
+			tmp_config.usb_address);
+	else
+		command_print(ctx, "USB address: %u", config.usb_address);
+}
+
+static void show_config_ip_address(struct command_context *ctx)
+{
+	if (!memcmp(config.ip_address, tmp_config.ip_address, 4))
+		command_print(ctx, "IP address: %d.%d.%d.%d",
+			config.ip_address[3], config.ip_address[2],
+			config.ip_address[1], config.ip_address[0]);
+	else
+		command_print(ctx, "IP address: %d.%d.%d.%d [%d.%d.%d.%d]",
+			config.ip_address[3], config.ip_address[2],
+			config.ip_address[1], config.ip_address[0],
+			tmp_config.ip_address[3], tmp_config.ip_address[2],
+			tmp_config.ip_address[1], tmp_config.ip_address[0]);
+
+	if (!memcmp(config.subnet_mask, tmp_config.subnet_mask, 4))
+		command_print(ctx, "Subnet mask: %d.%d.%d.%d",
+			config.subnet_mask[3], config.subnet_mask[2],
+			config.subnet_mask[1], config.subnet_mask[0]);
+	else
+		command_print(ctx, "Subnet mask: %d.%d.%d.%d [%d.%d.%d.%d]",
+			config.subnet_mask[3], config.subnet_mask[2],
+			config.subnet_mask[1], config.subnet_mask[0],
+			tmp_config.subnet_mask[3], tmp_config.subnet_mask[2],
+			tmp_config.subnet_mask[1], tmp_config.subnet_mask[0]);
+}
+
+static void show_config_mac_address(struct command_context *ctx)
+{
+	if (!memcmp(config.mac_address, tmp_config.mac_address, 6))
+		command_print(ctx, "MAC address: %.02x:%.02x:%.02x:%.02x:%.02x:%.02x",
+			config.mac_address[5], config.mac_address[4],
+			config.mac_address[3], config.mac_address[2],
+			config.mac_address[1], config.mac_address[0]);
+	else
+		command_print(ctx, "MAC address: %.02x:%.02x:%.02x:%.02x:%.02x:%.02x "
+			"[%.02x:%.02x:%.02x:%.02x:%.02x:%.02x]",
+			config.mac_address[5], config.mac_address[4],
+			config.mac_address[3], config.mac_address[2],
+			config.mac_address[1], config.mac_address[0],
+			tmp_config.mac_address[5], tmp_config.mac_address[4],
+			tmp_config.mac_address[3], tmp_config.mac_address[2],
+			tmp_config.mac_address[1], tmp_config.mac_address[0]);
+}
+
+static void show_config_target_power(struct command_context *ctx)
+{
+	const char *target_power;
+	const char *current_target_power;
+
+	if (!config.target_power)
+		target_power = "off";
+	else
+		target_power = "on";
+
+	if (!tmp_config.target_power)
+		current_target_power = "off";
+	else
+		current_target_power = "on";
+
+	if (config.target_power != tmp_config.target_power)
+		command_print(ctx, "Target power supply: %s [%s]", target_power,
+			current_target_power);
+	else
+		command_print(ctx, "Target power supply: %s", target_power);
+}
+
+static void show_config(struct command_context *ctx)
+{
+	command_print(ctx, "J-Link device configuration:");
+
+	show_config_usb_address(ctx);
+
+	if (jaylink_has_cap(caps, JAYLINK_DEV_CAP_SET_TARGET_POWER))
+		show_config_target_power(ctx);
+
+	if (jaylink_has_cap(caps, JAYLINK_DEV_CAP_ETHERNET)) {
+		show_config_ip_address(ctx);
+		show_config_mac_address(ctx);
+	}
+}
+
+static int poll_trace(uint8_t *buf, size_t *size)
+{
+	int ret;
+	uint32_t length;
+
+	length = *size;
+
+	ret = jaylink_swo_read(devh, buf, &length);
+
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_swo_read() failed: %s.", jaylink_strerror_name(ret));
+		return ERROR_FAIL;
+	}
+
+	*size = length;
+
+	return ERROR_OK;
+}
+
+static uint32_t calculate_trace_buffer_size(void)
+{
+	int ret;
+	uint32_t tmp;
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_GET_FREE_MEMORY))
+		return 0;
+
+	ret = jaylink_get_free_memory(devh, &tmp);
+
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_get_free_memory() failed: %s.",
+			jaylink_strerror_name(ret));
+		return ERROR_FAIL;
+	}
+
+	if (tmp > 0x3fff || tmp <= 0x600)
+		tmp = tmp >> 1;
+	else
+		tmp = tmp - 0x400;
+
+	return tmp & 0xffffff00;
+}
+
+static bool check_trace_freq(uint32_t freq, uint32_t div, uint32_t trace_freq)
+{
+	double min;
+	double deviation;
+
+	min = fabs(1.0 - (freq / ((double)trace_freq * div)));
+
+	while (freq / div > 0) {
+		deviation = fabs(1.0 - (freq / ((double)trace_freq * div)));
+
+		if (deviation < 0.03) {
+			LOG_DEBUG("Found suitable frequency divider %u with deviation of "
+				"%.02f %%.", div, deviation);
+			return true;
+		}
+
+		if (deviation < min)
+			min = deviation;
+
+		div++;
+	}
+
+	LOG_ERROR("Selected trace frequency is not supported by the device. "
+		"Please choose a different trace frequency.");
+	LOG_ERROR("Maximum permitted deviation is 3.00 %%, but only %.02f %% "
+		"could be achieved.", min * 100);
+
+	return false;
+}
+
+static int config_trace(bool enabled, enum tpio_pin_protocol pin_protocol,
+		uint32_t port_size, unsigned int *trace_freq)
+{
+	int ret;
+	uint32_t buffer_size;
+	uint32_t freq;
+	uint32_t div;
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_SWO)) {
+		LOG_ERROR("Trace capturing is not supported by the device.");
+		return ERROR_FAIL;
+	}
+
+	if (pin_protocol != ASYNC_UART) {
+		LOG_ERROR("Selected pin protocol is not supported.");
+		return ERROR_FAIL;
+	}
+
+	trace_enabled = enabled;
+
+	ret = jaylink_swo_stop(devh);
+
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_swo_stop() failed: %s.", jaylink_strerror_name(ret));
+		return ERROR_FAIL;
+	}
+
+	if (!enabled) {
+		/*
+		 * Adjust the SWD transaction buffer size as stopping SWO capturing
+		 * deallocates device internal memory.
+		 */
+		if (!adjust_swd_buffer_size())
+			return ERROR_FAIL;
+
+		return ERROR_OK;
+	}
+
+	buffer_size = calculate_trace_buffer_size();
+
+	if (!buffer_size) {
+		LOG_ERROR("Not enough free device memory to start trace capturing.");
+		return ERROR_FAIL;
+	}
+
+	ret = jaylink_swo_get_speeds(devh, JAYLINK_SWO_MODE_UART, &freq, &div);
+
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_swo_get_speeds() failed: %s.",
+			jaylink_strerror_name(ret));
+		return ERROR_FAIL;
+	}
+
+	if (!*trace_freq)
+		*trace_freq = freq / div;
+
+	if (!check_trace_freq(freq, div, *trace_freq))
+		return ERROR_FAIL;
+
+	LOG_DEBUG("Using %u bytes device memory for trace capturing.", buffer_size);
+
+	ret = jaylink_swo_start(devh, JAYLINK_SWO_MODE_UART, *trace_freq,
+		buffer_size);
+
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_start_swo() failed: %s.",
+			jaylink_strerror_name(ret));
+		return ERROR_FAIL;
+	}
+
+	/*
+	 * Adjust the SWD transaction buffer size as starting SWO capturing
+	 * allocates device internal memory.
+	 */
+	if (!adjust_swd_buffer_size())
+		return ERROR_FAIL;
+
+	return ERROR_OK;
+}
+
+COMMAND_HANDLER(jlink_handle_config_usb_address_command)
+{
+	uint8_t tmp;
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_READ_CONFIG)) {
+		command_print(CMD_CTX, "Reading configuration is not supported by the "
+			"device.");
+		return ERROR_OK;
+	}
+
+	if (!CMD_ARGC) {
+		show_config_usb_address(CMD_CTX);
+	} else if (CMD_ARGC == 1) {
+		if (sscanf(CMD_ARGV[0], "%" SCNd8, &tmp) != 1) {
+			command_print(CMD_CTX, "Invalid USB address: %s.", CMD_ARGV[0]);
+			return ERROR_FAIL;
+		}
+
+		if (tmp > JAYLINK_USB_ADDRESS_3) {
+			command_print(CMD_CTX, "Invalid USB address: %u.", tmp);
+			return ERROR_FAIL;
+		}
+
+		tmp_config.usb_address = tmp;
+	} else {
+		command_print(CMD_CTX, "Need exactly one argument for jlink config "
+			"usb.");
+		return ERROR_COMMAND_SYNTAX_ERROR;
+	}
+
+	return ERROR_OK;
+}
+
+COMMAND_HANDLER(jlink_handle_config_target_power_command)
+{
+	int enable;
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_READ_CONFIG)) {
+		command_print(CMD_CTX, "Reading configuration is not supported by the "
+			"device.");
+		return ERROR_OK;
+	}
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_SET_TARGET_POWER)) {
+		command_print(CMD_CTX, "Target power supply is not supported by the "
+			"device.");
+		return ERROR_OK;
+	}
+
+	if (!CMD_ARGC) {
+		show_config_target_power(CMD_CTX);
+	} else if (CMD_ARGC == 1) {
+		if (!strcmp(CMD_ARGV[0], "on")) {
+			enable = true;
+		} else if (!strcmp(CMD_ARGV[0], "off")) {
+			enable = false;
+		} else {
+			command_print(CMD_CTX, "Invalid argument: %s.", CMD_ARGV[0]);
+			return ERROR_FAIL;
+		}
+
+		tmp_config.target_power = enable;
+	} else {
+		command_print(CMD_CTX, "Need exactly one argument for jlink config "
+			"targetpower.");
+		return ERROR_COMMAND_SYNTAX_ERROR;
+	}
+
+	return ERROR_OK;
+}
+
+COMMAND_HANDLER(jlink_handle_config_mac_address_command)
+{
+	uint8_t addr[6];
+	int i;
+	char *e;
+	const char *str;
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_READ_CONFIG)) {
+		command_print(CMD_CTX, "Reading configuration is not supported by the "
+			"device.");
+		return ERROR_OK;
+	}
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_ETHERNET)) {
+		command_print(CMD_CTX, "Ethernet connectivity is not supported by the "
+			"device.");
+		return ERROR_OK;
+	}
+
+	if (!CMD_ARGC) {
+		show_config_mac_address(CMD_CTX);
+	} else if (CMD_ARGC == 1) {
+		str = CMD_ARGV[0];
+
+		if ((strlen(str) != 17) || (str[2] != ':' || str[5] != ':' || \
+				str[8] != ':' || str[11] != ':' || str[14] != ':')) {
+			command_print(CMD_CTX, "Invalid MAC address format.");
+			return ERROR_COMMAND_SYNTAX_ERROR;
+		}
+
+		for (i = 5; i >= 0; i--) {
+			addr[i] = strtoul(str, &e, 16);
+			str = e + 1;
+		}
+
+		if (!(addr[0] | addr[1] | addr[2] | addr[3] | addr[4] | addr[5])) {
+			command_print(CMD_CTX, "Invalid MAC address: zero address.");
+			return ERROR_COMMAND_SYNTAX_ERROR;
+		}
+
+		if (!(0x01 & addr[0])) {
+			command_print(CMD_CTX, "Invalid MAC address: multicast address.");
+			return ERROR_COMMAND_SYNTAX_ERROR;
+		}
+
+		memcpy(tmp_config.mac_address, addr, sizeof(addr));
+	} else {
+		command_print(CMD_CTX, "Need exactly one argument for jlink config "
+			" mac.");
+		return ERROR_COMMAND_SYNTAX_ERROR;
+	}
+
+	return ERROR_OK;
+}
+
+static bool string_to_ip(const char *s, uint8_t *ip, int *pos)
+{
+	uint8_t lip[4];
+	char *e;
+	const char *s_save = s;
+	int i;
+
+	if (!s)
+		return false;
+
+	for (i = 0; i < 4; i++) {
+		lip[i] = strtoul(s, &e, 10);
+
+		if (*e != '.' && i != 3)
+			return false;
+
+		s = e + 1;
+	}
+
+	*pos = e - s_save;
+	memcpy(ip, lip, sizeof(lip));
+
+	return true;
+}
+
+static void cpy_ip(uint8_t *dst, uint8_t *src)
+{
+	int i, j;
+
+	for (i = 0, j = 3; i < 4; i++, j--)
+		dst[i] = src[j];
+}
+
+COMMAND_HANDLER(jlink_handle_config_ip_address_command)
+{
+	uint8_t ip_address[4];
+	uint32_t subnet_mask = 0;
+	int i, len;
+	uint8_t subnet_bits = 24;
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_READ_CONFIG)) {
+		command_print(CMD_CTX, "Reading configuration is not supported by the "
+			"device.");
+		return ERROR_OK;
+	}
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_ETHERNET)) {
+		command_print(CMD_CTX, "Ethernet connectivity is not supported by the "
+			"device.");
+		return ERROR_OK;
+	}
+
+	if (!CMD_ARGC) {
+		show_config_ip_address(CMD_CTX);
+	} else {
+		if (!string_to_ip(CMD_ARGV[0], ip_address, &i))
+			return ERROR_COMMAND_SYNTAX_ERROR;
+
+		len = strlen(CMD_ARGV[0]);
+
+		/* Check for format A.B.C.D/E. */
+		if (i < len) {
+			if (CMD_ARGV[0][i] != '/')
+				return ERROR_COMMAND_SYNTAX_ERROR;
+
+			COMMAND_PARSE_NUMBER(u8, CMD_ARGV[0] + i + 1, subnet_bits);
+		} else if (CMD_ARGC > 1) {
+			if (!string_to_ip(CMD_ARGV[1], (uint8_t *)&subnet_mask, &i))
+				return ERROR_COMMAND_SYNTAX_ERROR;
+		}
+
+		if (!subnet_mask)
+			subnet_mask = (uint32_t)(subnet_bits < 32 ?
+				((1ULL << subnet_bits) - 1) : 0xffffffff);
+
+		cpy_ip(tmp_config.ip_address, ip_address);
+		cpy_ip(tmp_config.subnet_mask, (uint8_t *)&subnet_mask);
+	}
+
+	return ERROR_OK;
+}
+
+COMMAND_HANDLER(jlink_handle_config_reset_command)
+{
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_READ_CONFIG))
+		return ERROR_OK;
+
+	memcpy(&tmp_config, &config, sizeof(struct device_config));
+
+	return ERROR_OK;
+}
+
+
+COMMAND_HANDLER(jlink_handle_config_write_command)
+{
+	int ret;
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_READ_CONFIG)) {
+		command_print(CMD_CTX, "Reading configuration is not supported by the "
+			"device.");
+		return ERROR_OK;
+	}
+
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_WRITE_CONFIG)) {
+		command_print(CMD_CTX, "Writing configuration is not supported by the "
+			"device.");
+		return ERROR_OK;
+	}
+
+	if (!memcmp(&config, &tmp_config, sizeof(struct device_config))) {
+		command_print(CMD_CTX, "Operation not performed due to no changes in "
+			"the configuration.");
+		return ERROR_OK;
+	}
+
+	ret = jaylink_write_raw_config(devh, (const uint8_t *)&tmp_config);
+
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_write_raw_config() failed: %s.",
+			jaylink_strerror_name(ret));
+		return ERROR_FAIL;
+	}
+
+	if (!read_device_config(&config)) {
+		LOG_ERROR("Failed to read device configuration for verification.");
+		return ERROR_FAIL;
+	}
+
+	if (memcmp(&config, &tmp_config, sizeof(struct device_config))) {
+		LOG_ERROR("Verification of device configuration failed. Please check "
+			"your device.");
+		return ERROR_FAIL;
+	}
+
+	memcpy(&tmp_config, &config, sizeof(struct device_config));
+	command_print(CMD_CTX, "The new device configuration applies after power "
+		"cycling the J-Link device.");
+
+	return ERROR_OK;
+}
+
+COMMAND_HANDLER(jlink_handle_config_command)
+{
+	if (!jaylink_has_cap(caps, JAYLINK_DEV_CAP_READ_CONFIG)) {
+		command_print(CMD_CTX, "Device doesn't support reading configuration.");
+		return ERROR_OK;
+	}
+
+	if (CMD_ARGC == 0)
+		show_config(CMD_CTX);
+
+	return ERROR_OK;
+}
+
+static const struct command_registration jlink_config_subcommand_handlers[] = {
+	{
+		.name = "usb",
+		.handler = &jlink_handle_config_usb_address_command,
+		.mode = COMMAND_EXEC,
+		.help = "set the USB address",
+		.usage = "[0-3]",
+	},
+	{
+		.name = "targetpower",
+		.handler = &jlink_handle_config_target_power_command,
+		.mode = COMMAND_EXEC,
+		.help = "set the target power supply",
+		.usage = "[on|off]"
+	},
+	{
+		.name = "mac",
+		.handler = &jlink_handle_config_mac_address_command,
+		.mode = COMMAND_EXEC,
+		.help = "set the MAC Address",
+		.usage = "[ff:ff:ff:ff:ff:ff]",
+	},
+	{
+		.name = "ip",
+		.handler = &jlink_handle_config_ip_address_command,
+		.mode = COMMAND_EXEC,
+		.help = "set the IP address, where A.B.C.D is the IP address, "
+			"E the bit of the subnet mask, F.G.H.I the subnet mask",
+		.usage = "[A.B.C.D[/E] [F.G.H.I]]",
+	},
+	{
+		.name = "reset",
+		.handler = &jlink_handle_config_reset_command,
+		.mode = COMMAND_EXEC,
+		.help = "undo configuration changes"
+	},
+	{
+		.name = "write",
+		.handler = &jlink_handle_config_write_command,
+		.mode = COMMAND_EXEC,
+		.help = "write configuration to the device"
 	},
 	COMMAND_REGISTRATION_DONE
 };
 
-struct jtag_interface jlink_interface = {
+static const struct command_registration jlink_subcommand_handlers[] = {
+	{
+		.name = "jtag",
+		.handler = &jlink_handle_jlink_jtag_command,
+		.mode = COMMAND_EXEC,
+		.help = "select the JTAG command version",
+		.usage = "[2|3]",
+	},
+	{
+		.name = "targetpower",
+		.handler = &jlink_handle_target_power_command,
+		.mode = COMMAND_EXEC,
+		.help = "set the target power supply",
+		.usage = "<on|off>"
+	},
+	{
+		.name = "freemem",
+		.handler = &jlink_handle_free_memory_command,
+		.mode = COMMAND_EXEC,
+		.help = "show free device memory"
+	},
+	{
+		.name = "hwstatus",
+		.handler = &jlink_handle_hwstatus_command,
+		.mode = COMMAND_EXEC,
+		.help = "show the hardware status"
+	},
+	{
+		.name = "usb",
+		.handler = &jlink_usb_command,
+		.mode = COMMAND_CONFIG,
+		.help = "set the USB address of the device that should be used",
+		.usage = "<0-3>"
+	},
+	{
+		.name = "serial",
+		.handler = &jlink_serial_command,
+		.mode = COMMAND_CONFIG,
+		.help = "set the serial number of the device that should be used",
+		.usage = "<serial number>"
+	},
+	{
+		.name = "config",
+		.handler = &jlink_handle_config_command,
+		.mode = COMMAND_EXEC,
+		.help = "access the device configuration. If no argument is given "
+			"this will show the device configuration",
+		.chain = jlink_config_subcommand_handlers,
+	},
+	COMMAND_REGISTRATION_DONE
+};
+
+static const struct command_registration jlink_command_handlers[] = {
+	{
 		.name = "jlink",
+		.mode = COMMAND_ANY,
+		.help = "perform jlink management",
+		.chain = jlink_subcommand_handlers,
+	},
+	COMMAND_REGISTRATION_DONE
+};
+
+static int jlink_swd_init(void)
+{
+	iface = JAYLINK_TIF_SWD;
+
+	return ERROR_OK;
+}
+
+static void jlink_swd_write_reg(uint8_t cmd, uint32_t value, uint32_t ap_delay_clk)
+{
+	assert(!(cmd & SWD_CMD_RnW));
+	jlink_swd_queue_cmd(cmd, NULL, value, ap_delay_clk);
+}
 
-		.commands = jlink_command_handlers,
+static void jlink_swd_read_reg(uint8_t cmd, uint32_t *value, uint32_t ap_delay_clk)
+{
+	assert(cmd & SWD_CMD_RnW);
+	jlink_swd_queue_cmd(cmd, value, 0, ap_delay_clk);
+}
 
-		.execute_queue = &jlink_execute_queue,
-		.speed = &jlink_speed,
-		.speed_div = &jlink_speed_div,
-		.khz = &jlink_khz,
+static int_least32_t jlink_swd_frequency(int_least32_t hz)
+{
+	if (hz > 0)
+		jlink_speed(hz / 1000);
 
-		.init = &jlink_init,
-		.quit = &jlink_quit,
-	};
+	return hz;
+}
 
 /***************************************************************************/
 /* J-Link tap functions */
 
-
-static unsigned tap_length = 0;
+static unsigned tap_length;
+/* In SWD mode use tms buffer for direction control */
 static uint8_t tms_buffer[JLINK_TAP_BUFFER_SIZE];
 static uint8_t tdi_buffer[JLINK_TAP_BUFFER_SIZE];
 static uint8_t tdo_buffer[JLINK_TAP_BUFFER_SIZE];
 
 struct pending_scan_result {
-	int first;	/* First bit position in tdo_buffer to read */
-	int length; /* Number of bits to read */
-	struct scan_command *command; /* Corresponding scan command */
-	uint8_t *buffer;
+	int first; /* First bit position in tdo_buffer to read. */
+	int length; /* Number of bits to read. */
+	struct scan_command *command; /* Corresponding scan command. */
+	void *buffer;
 };
 
 #define MAX_PENDING_SCAN_RESULTS 256
@@ -691,45 +1619,37 @@ static void jlink_tap_ensure_space(int scans, int bits)
 	int available_bits = JLINK_TAP_BUFFER_SIZE * 8 - tap_length - 32;
 
 	if (scans > available_scans || bits > available_bits)
-	{
 		jlink_tap_execute();
-	}
 }
 
 static void jlink_tap_append_step(int tms, int tdi)
 {
-	int index = tap_length / 8;
+	int index_var = tap_length / 8;
 
-	if (index >= JLINK_TAP_BUFFER_SIZE)
-	{
-		LOG_ERROR("jlink_tap_append_step: overflow");
-		*(uint32_t *)0xFFFFFFFF = 0;
-		exit(-1);
-	}
+	assert(index_var < JLINK_TAP_BUFFER_SIZE);
 
 	int bit_index = tap_length % 8;
 	uint8_t bit = 1 << bit_index;
 
-	// we do not pad TMS, so be sure to initialize all bits
+	/* We do not pad TMS, so be sure to initialize all bits. */
 	if (0 == bit_index)
-	{
-		tms_buffer[index] = tdi_buffer[index] = 0;
-	}
+		tms_buffer[index_var] = tdi_buffer[index_var] = 0;
 
 	if (tms)
-		tms_buffer[index] |= bit;
+		tms_buffer[index_var] |= bit;
 	else
-		tms_buffer[index] &= ~bit;
+		tms_buffer[index_var] &= ~bit;
 
 	if (tdi)
-		tdi_buffer[index] |= bit;
+		tdi_buffer[index_var] |= bit;
 	else
-		tdi_buffer[index] &= ~bit;
+		tdi_buffer[index_var] &= ~bit;
 
 	tap_length++;
 }
 
-static void jlink_tap_append_scan(int length, uint8_t *buffer, struct scan_command *command)
+static void jlink_tap_append_scan(int length, uint8_t *buffer,
+		struct scan_command *command)
 {
 	struct pending_scan_result *pending_scan_result =
 		&pending_scan_results_buffer[pending_scan_results_length];
@@ -740,346 +1660,254 @@ static void jlink_tap_append_scan(int length, uint8_t *buffer, struct scan_comma
 	pending_scan_result->command = command;
 	pending_scan_result->buffer = buffer;
 
-	for (i = 0; i < length; i++)
-	{
+	for (i = 0; i < length; i++) {
 		int tms = (i < (length - 1)) ? 0 : 1;
 		int tdi = (buffer[i / 8] & (1 << (i % 8))) != 0;
 		jlink_tap_append_step(tms, tdi);
 	}
+
 	pending_scan_results_length++;
 }
 
-/* Pad and send a tap sequence to the device, and receive the answer.
- * For the purpose of padding we assume that we are in idle or pause state. */
+/*
+ * Pad and send a tap sequence to the device, and receive the answer. For the
+ * purpose of padding we assume that we are in idle or pause state.
+ */
 static int jlink_tap_execute(void)
 {
-	int byte_length;
 	int i;
-	int result;
+	int ret;
 
 	if (!tap_length)
 		return ERROR_OK;
 
-	/* JLink returns an extra NULL in packet when size of incoming
-	 * message is a multiple of 64, creates problems with USB comms.
-	 * WARNING: This will interfere with tap state counting. */
-	while ((DIV_ROUND_UP(tap_length, 8) % 64) == 0)
-	{
-		jlink_tap_append_step((tap_get_state() == TAP_RESET)?1:0, 0);
-	}
-
-	// number of full bytes (plus one if some would be left over)
-	byte_length = DIV_ROUND_UP(tap_length, 8);
-
-	bool use_jtag3 = jlink_hw_jtag_version >= 3;
-	usb_out_buffer[0] = use_jtag3 ? EMU_CMD_HW_JTAG3 : EMU_CMD_HW_JTAG2;
-	usb_out_buffer[1] = 0;
-	usb_out_buffer[2] = (tap_length >> 0) & 0xff;
-	usb_out_buffer[3] = (tap_length >> 8) & 0xff;
-	memcpy(usb_out_buffer + 4, tms_buffer, byte_length);
-	memcpy(usb_out_buffer + 4 + byte_length, tdi_buffer, byte_length);
+	jlink_last_state = jtag_debug_state_machine(tms_buffer, tdi_buffer,
+		tap_length, jlink_last_state);
 
 	jlink_last_state = jtag_debug_state_machine(tms_buffer, tdi_buffer,
-			tap_length, jlink_last_state);
+		tap_length, jlink_last_state);
 
-	result = jlink_usb_message(jlink_handle, 4 + 2 * byte_length, byte_length);
-	if (result != byte_length)
-	{
-		LOG_ERROR("jlink_tap_execute, wrong result %d (expected %d)", result, byte_length);
+	ret = jaylink_jtag_io(devh, tms_buffer, tdi_buffer, tdo_buffer,
+		tap_length, jtag_command_version);
+
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_jtag_io() failed: %s.", jaylink_strerror_name(ret));
 		jlink_tap_init();
 		return ERROR_JTAG_QUEUE_FAILED;
 	}
 
-	memcpy(tdo_buffer, usb_in_buffer, byte_length);
-
-	for (i = 0; i < pending_scan_results_length; i++)
-	{
+	for (i = 0; i < pending_scan_results_length; i++) {
 		struct pending_scan_result *pending_scan_result = &pending_scan_results_buffer[i];
 		uint8_t *buffer = pending_scan_result->buffer;
 		int length = pending_scan_result->length;
 		int first = pending_scan_result->first;
 		struct scan_command *command = pending_scan_result->command;
 
-		/* Copy to buffer */
+		/* Copy to buffer. */
 		buf_set_buf(tdo_buffer, first, buffer, 0, length);
 
-		DEBUG_JTAG_IO("pending scan result, length = %d", length);
-
-#ifdef _DEBUG_USB_COMMS_
-		jlink_debug_buffer(buffer, DIV_ROUND_UP(length, 8));
-#endif
+		DEBUG_JTAG_IO("Pending scan result, length = %d.", length);
 
-		if (jtag_read_buffer(buffer, command) != ERROR_OK)
-		{
+		if (jtag_read_buffer(buffer, command) != ERROR_OK) {
 			jlink_tap_init();
 			return ERROR_JTAG_QUEUE_FAILED;
 		}
 
 		if (pending_scan_result->buffer != NULL)
-		{
 			free(pending_scan_result->buffer);
-		}
 	}
 
 	jlink_tap_init();
+
 	return ERROR_OK;
 }
 
-/*****************************************************************************/
-/* JLink USB low-level functions */
-
-static struct jlink* jlink_usb_open()
+static void fill_buffer(uint8_t *buf, uint32_t val, uint32_t len)
 {
-	usb_init();
-
-	const uint16_t vids[] = { VID, 0 };
-	const uint16_t pids[] = { PID, 0 };
-	struct usb_dev_handle *dev;
-	if (jtag_usb_open(vids, pids, &dev) != ERROR_OK)
-		return NULL;
-
-	/* BE ***VERY CAREFUL*** ABOUT MAKING CHANGES IN THIS
-	 * AREA!!!!!!!!!!!  The behavior of libusb is not completely
-	 * consistent across Windows, Linux, and Mac OS X platforms.
-	 * The actions taken in the following compiler conditionals may
-	 * not agree with published documentation for libusb, but were
-	 * found to be necessary through trials and tribulations.  Even
-	 * little tweaks can break one or more platforms, so if you do
-	 * make changes test them carefully on all platforms before
-	 * committing them!
-	 */
-
-#if IS_WIN32 == 0
+	unsigned int tap_pos = tap_length;
 
-	usb_reset(dev);
-
-#if IS_DARWIN == 0
-
-	int timeout = 5;
-	/* reopen jlink after usb_reset
-	 * on win32 this may take a second or two to re-enumerate */
-	int retval;
-	while ((retval = jtag_usb_open(vids, pids, &dev)) != ERROR_OK)
-	{
-		usleep(1000);
-		timeout--;
-		if (!timeout) {
-			break;
-		}
+	while (len > 32) {
+		buf_set_u32(buf, tap_pos, 32, val);
+		len -= 32;
+		tap_pos += 32;
 	}
-	if (ERROR_OK != retval)
-		return NULL;
-#endif
 
-#endif
+	if (len)
+		buf_set_u32(buf, tap_pos, len, val);
+}
 
-	/* usb_set_configuration required under win32 */
-	struct usb_device *udev = usb_device(dev);
-	usb_set_configuration(dev, udev->config[0].bConfigurationValue);
-	usb_claim_interface(dev, 0);
+static void jlink_queue_data_out(const uint8_t *data, uint32_t len)
+{
+	const uint32_t dir_out = 0xffffffff;
 
-#if 0
-	/*
-	 * This makes problems under Mac OS X. And is not needed
-	 * under Windows. Hopefully this will not break a linux build
-	 */
-	usb_set_altinterface(result->usb_handle, 0);
-#endif
-	struct usb_interface *iface = udev->config->interface;
-	struct usb_interface_descriptor *desc = iface->altsetting;
-	for (int i = 0; i < desc->bNumEndpoints; i++)
-	{
-		uint8_t epnum = desc->endpoint[i].bEndpointAddress;
-		bool is_input = epnum & 0x80;
-		LOG_DEBUG("usb ep %s %02x", is_input ? "in" : "out", epnum);
-		if (is_input)
-			jlink_read_ep = epnum;
-		else
-			jlink_write_ep = epnum;
-	}
-
-	struct jlink *result = malloc(sizeof(struct jlink));
-	result->usb_handle = dev;
-	return result;
+	if (data)
+		bit_copy(tdi_buffer, tap_length, data, 0, len);
+	else
+		fill_buffer(tdi_buffer, 0, len);
+
+	fill_buffer(tms_buffer, dir_out, len);
+	tap_length += len;
 }
 
-static void jlink_usb_close(struct jlink *jlink)
+static void jlink_queue_data_in(uint32_t len)
 {
-	usb_close(jlink->usb_handle);
-	free(jlink);
+	const uint32_t dir_in = 0;
+
+	fill_buffer(tms_buffer, dir_in, len);
+	tap_length += len;
 }
 
-/* Send a message and receive the reply. */
-static int jlink_usb_message(struct jlink *jlink, int out_length, int in_length)
+static int jlink_swd_switch_seq(enum swd_special_seq seq)
 {
-	int result;
-
-	result = jlink_usb_write(jlink, out_length);
-	if (result != out_length)
-	{
-		LOG_ERROR("usb_bulk_write failed (requested=%d, result=%d)",
-				out_length, result);
-		return ERROR_JTAG_DEVICE_ERROR;
+	const uint8_t *s;
+	unsigned int s_len;
+
+	switch (seq) {
+		case LINE_RESET:
+			LOG_DEBUG("SWD line reset");
+			s = swd_seq_line_reset;
+			s_len = swd_seq_line_reset_len;
+			break;
+		case JTAG_TO_SWD:
+			LOG_DEBUG("JTAG-to-SWD");
+			s = swd_seq_jtag_to_swd;
+			s_len = swd_seq_jtag_to_swd_len;
+			break;
+		case SWD_TO_JTAG:
+			LOG_DEBUG("SWD-to-JTAG");
+			s = swd_seq_swd_to_jtag;
+			s_len = swd_seq_swd_to_jtag_len;
+			break;
+		default:
+			LOG_ERROR("Sequence %d not supported.", seq);
+			return ERROR_FAIL;
 	}
 
-	result = jlink_usb_read(jlink, in_length);
-	if ((result != in_length) && (result != (in_length + 1)))
-	{
-		LOG_ERROR("usb_bulk_read failed (requested=%d, result=%d)",
-				in_length, result);
-		return ERROR_JTAG_DEVICE_ERROR;
-	}
+	jlink_queue_data_out(s, s_len);
 
-	if (jlink_hw_jtag_version < 3)
-		return result;
+	return ERROR_OK;
+}
 
-	int result2 = ERROR_OK;
-	if (result == in_length)
-	{
-		/* Must read the result from the EMU too */
-		result2 = jlink_usb_read_emu_result(jlink);
-		if (1 != result2)
-		{
-			LOG_ERROR("jlink_usb_read_emu_result retried requested = 1, result=%d, in_length=%i", result2,in_length);
-			/* Try again once, should only happen if (in_length%64 == 0) */
-			result2 = jlink_usb_read_emu_result(jlink);
-			if (1 != result2)
-			{
-				LOG_ERROR("jlink_usb_read_emu_result failed "
-					"(requested = 1, result=%d)", result2);
-				return ERROR_JTAG_DEVICE_ERROR;
-			}
-		}
+static int jlink_swd_run_queue(void)
+{
+	int i;
+	int ret;
 
-		/* Check the result itself */
-		result2 = usb_emu_result_buffer[0];
-	}
-	else
-	{
-		/* Save the result, then remove it from return value */
-		result2 = usb_in_buffer[result--];
-	}
+	LOG_DEBUG("Executing %d queued transactions.", pending_scan_results_length);
 
-	if (result2)
-	{
-		LOG_ERROR("jlink_usb_message failed with result=%d)", result2);
-		return ERROR_JTAG_DEVICE_ERROR;
+	if (queued_retval != ERROR_OK) {
+		LOG_DEBUG("Skipping due to previous errors: %d.", queued_retval);
+		goto skip;
 	}
 
-	return result;
-}
+	/*
+	 * A transaction must be followed by another transaction or at least 8 idle
+	 * cycles to ensure that data is clocked through the AP.
+	 */
+	jlink_queue_data_out(NULL, 8);
 
-/* calls the given usb_bulk_* function, allowing for the data to trickle in with some timeouts  */
-static int usb_bulk_with_retries(
-		int (*f)(usb_dev_handle *, int, char *, int, int),
-		usb_dev_handle *dev, int ep,
-		char *bytes, int size, int timeout)
-{
-	int tries = 3, count = 0;
+	ret = jaylink_swd_io(devh, tms_buffer, tdi_buffer, tdo_buffer, tap_length);
 
-	while (tries && (count < size))
-	{
-		int result = f(dev, ep, bytes + count, size - count, timeout);
-		if (result > 0)
-			count += result;
-		else if ((-ETIMEDOUT != result) || !--tries)
-			return result;
+	if (ret != JAYLINK_OK) {
+		LOG_ERROR("jaylink_swd_io() failed: %s.", jaylink_strerror_name(ret));
+		goto skip;
 	}
-	return count;
-}
 
-static int wrap_usb_bulk_write(usb_dev_handle *dev, int ep,
-			       char *buff, int size, int timeout)
-{
-	/* usb_bulk_write() takes const char *buff */
-	return usb_bulk_write(dev, ep, buff, size, timeout);
-}
+	for (i = 0; i < pending_scan_results_length; i++) {
+		int ack = buf_get_u32(tdo_buffer, pending_scan_results_buffer[i].first, 3);
+
+		if (ack != SWD_ACK_OK) {
+			LOG_DEBUG("SWD ack not OK: %d %s", ack,
+				  ack == SWD_ACK_WAIT ? "WAIT" : ack == SWD_ACK_FAULT ? "FAULT" : "JUNK");
+			queued_retval = ack == SWD_ACK_WAIT ? ERROR_WAIT : ERROR_FAIL;
+			goto skip;
+		} else if (pending_scan_results_buffer[i].length) {
+			uint32_t data = buf_get_u32(tdo_buffer, 3 + pending_scan_results_buffer[i].first, 32);
+			int parity = buf_get_u32(tdo_buffer, 3 + 32 + pending_scan_results_buffer[i].first, 1);
+
+			if (parity != parity_u32(data)) {
+				LOG_ERROR("SWD: Read data parity mismatch.");
+				queued_retval = ERROR_FAIL;
+				goto skip;
+			}
 
-static inline int usb_bulk_write_ex(usb_dev_handle *dev, int ep,
-		char *bytes, int size, int timeout)
-{
-	return usb_bulk_with_retries(&wrap_usb_bulk_write,
-			dev, ep, bytes, size, timeout);
-}
+			if (pending_scan_results_buffer[i].buffer)
+				*(uint32_t *)pending_scan_results_buffer[i].buffer = data;
+		}
+	}
 
-static inline int usb_bulk_read_ex(usb_dev_handle *dev, int ep,
-		char *bytes, int size, int timeout)
-{
-	return usb_bulk_with_retries(&usb_bulk_read,
-			dev, ep, bytes, size, timeout);
+skip:
+	jlink_tap_init();
+	ret = queued_retval;
+	queued_retval = ERROR_OK;
+
+	return ret;
 }
 
-/* Write data from out_buffer to USB. */
-static int jlink_usb_write(struct jlink *jlink, int out_length)
+static void jlink_swd_queue_cmd(uint8_t cmd, uint32_t *dst, uint32_t data, uint32_t ap_delay_clk)
 {
-	int result;
-
-	if (out_length > JLINK_OUT_BUFFER_SIZE)
-	{
-		LOG_ERROR("jlink_write illegal out_length=%d (max=%d)", out_length, JLINK_OUT_BUFFER_SIZE);
-		return -1;
+	uint8_t data_parity_trn[DIV_ROUND_UP(32 + 1, 8)];
+	if (tap_length + 46 + 8 + ap_delay_clk >= sizeof(tdi_buffer) * 8 ||
+	    pending_scan_results_length == MAX_PENDING_SCAN_RESULTS) {
+		/* Not enough room in the queue. Run the queue. */
+		queued_retval = jlink_swd_run_queue();
 	}
 
-	result = usb_bulk_write_ex(jlink->usb_handle, jlink_write_ep,
-		(char *)usb_out_buffer, out_length, JLINK_USB_TIMEOUT);
+	if (queued_retval != ERROR_OK)
+		return;
 
-	DEBUG_JTAG_IO("jlink_usb_write, out_length = %d, result = %d", out_length, result);
+	cmd |= SWD_CMD_START | SWD_CMD_PARK;
 
-#ifdef _DEBUG_USB_COMMS_
-	jlink_debug_buffer(usb_out_buffer, out_length);
-#endif
-	return result;
-}
+	jlink_queue_data_out(&cmd, 8);
 
-/* Read data from USB into in_buffer. */
-static int jlink_usb_read(struct jlink *jlink, int expected_size)
-{
-	int result = usb_bulk_read_ex(jlink->usb_handle, jlink_read_ep,
-		(char *)usb_in_buffer, expected_size, JLINK_USB_TIMEOUT);
+	pending_scan_results_buffer[pending_scan_results_length].first = tap_length;
 
-	DEBUG_JTAG_IO("jlink_usb_read, result = %d", result);
+	if (cmd & SWD_CMD_RnW) {
+		/* Queue a read transaction. */
+		pending_scan_results_buffer[pending_scan_results_length].length = 32;
+		pending_scan_results_buffer[pending_scan_results_length].buffer = dst;
 
-#ifdef _DEBUG_USB_COMMS_
-	jlink_debug_buffer(usb_in_buffer, result);
-#endif
-	return result;
-}
+		jlink_queue_data_in(1 + 3 + 32 + 1 + 1);
+	} else {
+		/* Queue a write transaction. */
+		pending_scan_results_buffer[pending_scan_results_length].length = 0;
+		jlink_queue_data_in(1 + 3 + 1);
 
-/* Read the result from the previous EMU cmd into result_buffer. */
-static int jlink_usb_read_emu_result(struct jlink *jlink)
-{
-	int result = usb_bulk_read_ex(jlink->usb_handle, jlink_read_ep,
-		(char *)usb_emu_result_buffer, 1 /* JLINK_EMU_RESULT_BUFFER_SIZE */,
-		JLINK_USB_TIMEOUT);
+		buf_set_u32(data_parity_trn, 0, 32, data);
+		buf_set_u32(data_parity_trn, 32, 1, parity_u32(data));
 
-	DEBUG_JTAG_IO("jlink_usb_read_result, result = %d", result);
+		jlink_queue_data_out(data_parity_trn, 32 + 1);
+	}
 
-#ifdef _DEBUG_USB_COMMS_
-	jlink_debug_buffer(usb_emu_result_buffer, result);
-#endif
-	return result;
-}
+	pending_scan_results_length++;
 
-#ifdef _DEBUG_USB_COMMS_
-#define BYTES_PER_LINE  16
+	/* Insert idle cycles after AP accesses to avoid WAIT. */
+	if (cmd & SWD_CMD_APnDP)
+		jlink_queue_data_out(NULL, ap_delay_clk);
+}
 
-static void jlink_debug_buffer(uint8_t *buffer, int length)
-{
-	char line[81];
-	char s[4];
-	int i;
-	int j;
+static const struct swd_driver jlink_swd = {
+	.init = &jlink_swd_init,
+	.frequency = &jlink_swd_frequency,
+	.switch_seq = &jlink_swd_switch_seq,
+	.read_reg = &jlink_swd_read_reg,
+	.write_reg = &jlink_swd_write_reg,
+	.run = &jlink_swd_run_queue,
+};
 
-	for (i = 0; i < length; i += BYTES_PER_LINE)
-	{
-		snprintf(line, 5, "%04x", i);
-		for (j = i; j < i + BYTES_PER_LINE && j < length; j++)
-		{
-			snprintf(s, 4, " %02x", buffer[j]);
-			strcat(line, s);
-		}
-		LOG_DEBUG("%s", line);
-	}
-}
-#endif
+static const char * const jlink_transports[] = { "jtag", "swd", NULL };
 
+struct jtag_interface jlink_interface = {
+	.name = "jlink",
+	.commands = jlink_command_handlers,
+	.transports = jlink_transports,
+	.swd = &jlink_swd,
+	.execute_queue = &jlink_execute_queue,
+	.speed = &jlink_speed,
+	.speed_div = &jlink_speed_div,
+	.khz = &jlink_khz,
+	.init = &jlink_init,
+	.quit = &jlink_quit,
+	.config_trace = &config_trace,
+	.poll_trace = &poll_trace,
+};