diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index 480c860..f54edec 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -319,6 +319,8 @@ Code  Seq#(hex)	Include File		Comments
 0xB0	all	RATIO devices		in development:
 					<mailto:vgo@ratio.de>
 0xB1	00-1F	PPPoX			<mailto:mostrows@styx.uwaterloo.ca>
+0xB2	00-0F	linux/jtag.h		JTAG driver
+					<mailto:oleksandrs@mellanox.com>
 0xB3	00	linux/mmc/ioctl.h
 0xB4	00-0F	linux/gpio.h		<mailto:linux-gpio@vger.kernel.org>
 0xB5	00-0F	uapi/linux/rpmsg.h	<mailto:linux-remoteproc@vger.kernel.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 6cfd167..b70c6af 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7690,6 +7690,14 @@ L:	linux-serial@vger.kernel.org
 S:	Maintained
 F:	drivers/tty/serial/jsm/
 
+JTAG SUBSYSTEM
+M:	Oleksandr Shamray <oleksandrs@mellanox.com>
+M:	Vadim Pasternak <vadimp@mellanox.com>
+S:	Maintained
+F:	include/linux/jtag.h
+F:	include/uapi/linux/jtag.h
+F:	drivers/jtag/
+
 K10TEMP HARDWARE MONITORING DRIVER
 M:	Clemens Ladisch <clemens@ladisch.de>
 L:	linux-hwmon@vger.kernel.org
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 95b9ccc..bb71e48 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -217,4 +217,6 @@ source "drivers/siox/Kconfig"
 
 source "drivers/slimbus/Kconfig"
 
+source "drivers/jtag/Kconfig"
+
 endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index 24cd470..c92636b 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -185,3 +185,4 @@ obj-$(CONFIG_TEE)		+= tee/
 obj-$(CONFIG_MULTIPLEXER)	+= mux/
 obj-$(CONFIG_UNISYS_VISORBUS)	+= visorbus/
 obj-$(CONFIG_SIOX)		+= siox/
+obj-$(CONFIG_JTAG)		+= jtag/
diff --git a/drivers/jtag/Kconfig b/drivers/jtag/Kconfig
new file mode 100644
index 0000000..47771fc
--- /dev/null
+++ b/drivers/jtag/Kconfig
@@ -0,0 +1,17 @@
+menuconfig JTAG
+	tristate "JTAG support"
+	help
+	  This provides basic core functionality support for JTAG class devices.
+	  Hardware that is equipped with a JTAG microcontroller can be
+	  supported by using this driver's interfaces.
+	  This driver exposes a set of IOCTLs to the user space for
+	  the following commands:
+	    SDR: Performs an IEEE 1149.1 Data Register scan
+	    SIR: Performs an IEEE 1149.1 Instruction Register scan.
+	    RUNTEST: Forces the IEEE 1149.1 bus to a run state for a specified
+	    number of clocks or a specified time period.
+
+	  If you want this support, you should say Y here.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called jtag.
diff --git a/drivers/jtag/Makefile b/drivers/jtag/Makefile
new file mode 100644
index 0000000..af37493
--- /dev/null
+++ b/drivers/jtag/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_JTAG)		+= jtag.o
diff --git a/drivers/jtag/jtag.c b/drivers/jtag/jtag.c
new file mode 100644
index 0000000..6657b84
--- /dev/null
+++ b/drivers/jtag/jtag.c
@@ -0,0 +1,274 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// drivers/jtag/jtag.c
+//
+// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2018 Oleksandr Shamray <oleksandrs@mellanox.com>
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/jtag.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/rtnetlink.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <uapi/linux/jtag.h>
+
+struct jtag {
+	struct miscdevice miscdev;
+	const struct jtag_ops *ops;
+	int id;
+	unsigned long priv[0];
+};
+
+static DEFINE_IDA(jtag_ida);
+
+void *jtag_priv(struct jtag *jtag)
+{
+	return jtag->priv;
+}
+EXPORT_SYMBOL_GPL(jtag_priv);
+
+static long jtag_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct jtag *jtag = file->private_data;
+	struct jtag_run_test_idle idle;
+	struct jtag_xfer xfer;
+	u8 *xfer_data;
+	u32 data_size;
+	u32 value;
+	int err;
+
+	if (!arg)
+		return -EINVAL;
+
+	switch (cmd) {
+	case JTAG_GIOCFREQ:
+		if (!jtag->ops->freq_get)
+			return -EOPNOTSUPP;
+
+		err = jtag->ops->freq_get(jtag, &value);
+		if (err)
+			break;
+
+		if (put_user(value, (__u32 __user *)arg))
+			err = -EFAULT;
+		break;
+
+	case JTAG_SIOCFREQ:
+		if (!jtag->ops->freq_set)
+			return -EOPNOTSUPP;
+
+		if (get_user(value, (__u32 __user *)arg))
+			return -EFAULT;
+		if (value == 0)
+			return -EINVAL;
+
+		err = jtag->ops->freq_set(jtag, value);
+		break;
+
+	case JTAG_IOCRUNTEST:
+		if (copy_from_user(&idle, (const void __user *)arg,
+				   sizeof(struct jtag_run_test_idle)))
+			return -EFAULT;
+
+		if (idle.endstate > JTAG_STATE_PAUSEDR)
+			return -EINVAL;
+
+		if (idle.reset > JTAG_FORCE_RESET)
+			return -EINVAL;
+
+		err = jtag->ops->idle(jtag, &idle);
+		break;
+
+	case JTAG_IOCXFER:
+		if (copy_from_user(&xfer, (const void __user *)arg,
+				   sizeof(struct jtag_xfer)))
+			return -EFAULT;
+
+		if (xfer.length >= JTAG_MAX_XFER_DATA_LEN)
+			return -EINVAL;
+
+		if (xfer.type > JTAG_SDR_XFER)
+			return -EINVAL;
+
+		if (xfer.direction > JTAG_WRITE_XFER)
+			return -EINVAL;
+
+		if (xfer.endstate > JTAG_STATE_PAUSEDR)
+			return -EINVAL;
+
+		data_size = DIV_ROUND_UP(xfer.length, BITS_PER_BYTE);
+		xfer_data = memdup_user(u64_to_user_ptr(xfer.tdio), data_size);
+		if (IS_ERR(xfer_data))
+			return -EFAULT;
+
+		err = jtag->ops->xfer(jtag, &xfer, xfer_data);
+		if (err) {
+			kfree(xfer_data);
+			return err;
+		}
+
+		err = copy_to_user(u64_to_user_ptr(xfer.tdio),
+				   (void *)xfer_data, data_size);
+		kfree(xfer_data);
+		if (err)
+			return -EFAULT;
+
+		if (copy_to_user((void __user *)arg, (void *)&xfer,
+				 sizeof(struct jtag_xfer)))
+			return -EFAULT;
+		break;
+
+	case JTAG_GIOCSTATUS:
+		err = jtag->ops->status_get(jtag, &value);
+		if (err)
+			break;
+
+		err = put_user(value, (__u32 __user *)arg);
+		break;
+	case JTAG_SIOCMODE:
+		if (!jtag->ops->mode_set)
+			return -EOPNOTSUPP;
+
+		if (get_user(value, (__u32 __user *)arg))
+			return -EFAULT;
+		if (value == 0)
+			return -EINVAL;
+
+		err = jtag->ops->mode_set(jtag, value);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+	return err;
+}
+
+static int jtag_open(struct inode *inode, struct file *file)
+{
+	struct jtag *jtag = container_of(file->private_data, struct jtag, miscdev);
+
+	file->private_data = jtag;
+	return nonseekable_open(inode, file);
+}
+
+static const struct file_operations jtag_fops = {
+	.owner		= THIS_MODULE,
+	.open		= jtag_open,
+	.llseek		= noop_llseek,
+	.unlocked_ioctl = jtag_ioctl,
+};
+
+struct jtag *jtag_alloc(struct device *host, size_t priv_size,
+			const struct jtag_ops *ops)
+{
+	struct jtag *jtag;
+
+	if (!host)
+		return NULL;
+
+	if (!ops)
+		return NULL;
+
+	if (!ops->idle || !ops->status_get || !ops->xfer)
+		return NULL;
+
+	jtag = kzalloc(sizeof(*jtag) + priv_size, GFP_KERNEL);
+	if (!jtag)
+		return NULL;
+
+	jtag->ops = ops;
+	jtag->miscdev.parent = host;
+
+	return jtag;
+}
+EXPORT_SYMBOL_GPL(jtag_alloc);
+
+void jtag_free(struct jtag *jtag)
+{
+	kfree(jtag);
+}
+EXPORT_SYMBOL_GPL(jtag_free);
+
+static int jtag_register(struct jtag *jtag)
+{
+	struct device *dev = jtag->miscdev.parent;
+	int err;
+	int id;
+
+	if (!dev)
+		return -ENODEV;
+
+	id = ida_simple_get(&jtag_ida, 0, 0, GFP_KERNEL);
+	if (id < 0)
+		return id;
+
+	jtag->id = id;
+
+	jtag->miscdev.fops =  &jtag_fops;
+	jtag->miscdev.minor = MISC_DYNAMIC_MINOR;
+	jtag->miscdev.name = kasprintf(GFP_KERNEL, "jtag%d", id);
+	if (!jtag->miscdev.name) {
+		err = -ENOMEM;
+		goto err_jtag_alloc;
+	}
+
+	err = misc_register(&jtag->miscdev);
+	if (err) {
+		dev_err(jtag->miscdev.parent, "Unable to register device\n");
+		goto err_jtag_name;
+	}
+	return 0;
+
+err_jtag_name:
+	kfree(jtag->miscdev.name);
+err_jtag_alloc:
+	ida_simple_remove(&jtag_ida, id);
+	return err;
+}
+
+static void jtag_unregister(struct jtag *jtag)
+{
+	misc_deregister(&jtag->miscdev);
+	kfree(jtag->miscdev.name);
+	ida_simple_remove(&jtag_ida, jtag->id);
+}
+
+static void devm_jtag_unregister(struct device *dev, void *res)
+{
+	jtag_unregister(*(struct jtag **)res);
+}
+
+int devm_jtag_register(struct device *dev, struct jtag *jtag)
+{
+	struct jtag **ptr;
+	int ret;
+
+	ptr = devres_alloc(devm_jtag_unregister, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return -ENOMEM;
+
+	ret = jtag_register(jtag);
+	if (!ret) {
+		*ptr = jtag;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(devm_jtag_register);
+
+static void __exit jtag_exit(void)
+{
+	ida_destroy(&jtag_ida);
+}
+
+module_exit(jtag_exit);
+
+MODULE_AUTHOR("Oleksandr Shamray <oleksandrs@mellanox.com>");
+MODULE_DESCRIPTION("Generic jtag support");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/jtag.h b/include/linux/jtag.h
new file mode 100644
index 0000000..fd5dd79
--- /dev/null
+++ b/include/linux/jtag.h
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0
+// include/linux/jtag.h - JTAG class driver
+//
+// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2018 Oleksandr Shamray <oleksandrs@mellanox.com>
+
+#ifndef __JTAG_H
+#define __JTAG_H
+
+#include <linux/types.h>
+#include <uapi/linux/jtag.h>
+
+#define JTAG_MAX_XFER_DATA_LEN 65535
+
+struct jtag;
+/**
+ * struct jtag_ops - callbacks for JTAG control functions:
+ *
+ * @freq_get: get frequency function. Filled by dev driver
+ * @freq_set: set frequency function. Filled by dev driver
+ * @status_get: set status function. Mandatory func. Filled by dev driver
+ * @idle: set JTAG to idle state function. Mandatory func. Filled by dev driver
+ * @xfer: send JTAG xfer function. Mandatory func. Filled by dev driver
+ * @mode_set: set specific work mode for JTAG. Filled by dev driver
+ */
+struct jtag_ops {
+	int (*freq_get)(struct jtag *jtag, u32 *freq);
+	int (*freq_set)(struct jtag *jtag, u32 freq);
+	int (*status_get)(struct jtag *jtag, u32 *state);
+	int (*idle)(struct jtag *jtag, struct jtag_run_test_idle *idle);
+	int (*xfer)(struct jtag *jtag, struct jtag_xfer *xfer, u8 *xfer_data);
+	int (*mode_set)(struct jtag *jtag, u32 mode_mask);
+};
+
+void *jtag_priv(struct jtag *jtag);
+int devm_jtag_register(struct device *dev, struct jtag *jtag);
+struct jtag *jtag_alloc(struct device *host, size_t priv_size,
+			const struct jtag_ops *ops);
+void jtag_free(struct jtag *jtag);
+
+#endif /* __JTAG_H */
diff --git a/include/uapi/linux/jtag.h b/include/uapi/linux/jtag.h
new file mode 100644
index 0000000..4f521b8
--- /dev/null
+++ b/include/uapi/linux/jtag.h
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0
+// include/uapi/linux/jtag.h - JTAG class driver uapi
+//
+// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
+// Copyright (c) 2018 Oleksandr Shamray <oleksandrs@mellanox.com>
+
+#ifndef __UAPI_LINUX_JTAG_H
+#define __UAPI_LINUX_JTAG_H
+
+/*
+ * JTAG_XFER_HW_MODE: JTAG hardware mode. Used to set HW drived or bitbang
+ * mode. This is bitmask param of ioctl JTAG_SIOCMODE command
+ */
+#define  JTAG_XFER_HW_MODE 1
+
+/**
+ * enum jtag_endstate:
+ *
+ * @JTAG_STATE_IDLE: JTAG state machine IDLE state
+ * @JTAG_STATE_PAUSEIR: JTAG state machine PAUSE_IR state
+ * @JTAG_STATE_PAUSEDR: JTAG state machine PAUSE_DR state
+ */
+enum jtag_endstate {
+	JTAG_STATE_IDLE = 0,
+	JTAG_STATE_PAUSEIR = 1,
+	JTAG_STATE_PAUSEDR = 2,
+};
+
+/**
+ * enum jtag_reset:
+ *
+ * @JTAG_NO_RESET: JTAG run TAP from current state
+ * @JTAG_FORCE_RESET: JTAG force TAP to reset state
+ */
+enum jtag_reset {
+	JTAG_NO_RESET = 0,
+	JTAG_FORCE_RESET = 1,
+};
+
+/**
+ * enum jtag_xfer_type:
+ *
+ * @JTAG_SIR_XFER: SIR transfer
+ * @JTAG_SDR_XFER: SDR transfer
+ */
+enum jtag_xfer_type {
+	JTAG_SIR_XFER = 0,
+	JTAG_SDR_XFER = 1,
+};
+
+/**
+ * enum jtag_xfer_direction:
+ *
+ * @JTAG_READ_XFER: read transfer
+ * @JTAG_WRITE_XFER: write transfer
+ */
+enum jtag_xfer_direction {
+	JTAG_READ_XFER = 0,
+	JTAG_WRITE_XFER = 1,
+};
+
+/**
+ * struct jtag_run_test_idle - forces JTAG state machine to
+ * RUN_TEST/IDLE state
+ *
+ * @reset: 0 - run IDLE/PAUSE from current state
+ *         1 - go through TEST_LOGIC/RESET state before  IDLE/PAUSE
+ * @end: completion flag
+ * @tck: clock counter
+ *
+ * Structure provide interface to JTAG device for  JTAG IDLE execution.
+ */
+struct jtag_run_test_idle {
+	__u8	reset;
+	__u8	endstate;
+	__u8	tck;
+};
+
+/**
+ * struct jtag_xfer - jtag xfer:
+ *
+ * @type: transfer type
+ * @direction: xfer direction
+ * @length: xfer bits len
+ * @tdio : xfer data array
+ * @endir: xfer end state
+ *
+ * Structure provide interface to JTAG device for JTAG SDR/SIR xfer execution.
+ */
+struct jtag_xfer {
+	__u8	type;
+	__u8	direction;
+	__u8	endstate;
+	__u8	padding;
+	__u32	length;
+	__u64	tdio;
+};
+
+/* ioctl interface */
+#define __JTAG_IOCTL_MAGIC	0xb2
+
+#define JTAG_IOCRUNTEST	_IOW(__JTAG_IOCTL_MAGIC, 0, struct jtag_run_test_idle)
+#define JTAG_SIOCFREQ	_IOW(__JTAG_IOCTL_MAGIC, 1, unsigned int)
+#define JTAG_GIOCFREQ	_IOR(__JTAG_IOCTL_MAGIC, 2, unsigned int)
+#define JTAG_IOCXFER	_IOWR(__JTAG_IOCTL_MAGIC, 3, struct jtag_xfer)
+#define JTAG_GIOCSTATUS _IOWR(__JTAG_IOCTL_MAGIC, 4, enum jtag_endstate)
+#define JTAG_SIOCMODE	_IOW(__JTAG_IOCTL_MAGIC, 5, unsigned int)
+
+#endif /* __UAPI_LINUX_JTAG_H */
