Merge tag 'char-misc-4.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc driver updates from Greg KH:
 "Here is the big char/misc driver update for 4.4-rc1.  Lots of
  different driver and subsystem updates, hwtracing being the largest
  with the addition of some new platforms that are now supported.  Full
  details in the shortlog.

  All of these have been in linux-next for a long time with no reported
  issues"

* tag 'char-misc-4.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (181 commits)
  fpga: socfpga: Fix check of return value of devm_request_irq
  lkdtm: fix ACCESS_USERSPACE test
  mcb: Destroy IDA on module unload
  mcb: Do not return zero on error path in mcb_pci_probe()
  mei: bus: set the device name before running fixup
  mei: bus: use correct lock ordering
  mei: Fix debugfs filename in error output
  char: ipmi: ipmi_ssif: Replace timeval with timespec64
  fpga: zynq-fpga: Fix issue with drvdata being overwritten.
  fpga manager: remove unnecessary null pointer checks
  fpga manager: ensure lifetime with of_fpga_mgr_get
  fpga: zynq-fpga: Change fw format to handle bin instead of bit.
  fpga: zynq-fpga: Fix unbalanced clock handling
  misc: sram: partition base address belongs to __iomem space
  coresight: etm3x: adding documentation for sysFS's cpu interface
  vme: 8-bit status/id takes 256 values, not 255
  fpga manager: Adding FPGA Manager support for Xilinx Zynq 7000
  ARM: zynq: dt: Updated devicetree for Zynq 7000 platform.
  ARM: dt: fpga: Added binding docs for Xilinx Zynq FPGA manager.
  ver_linux: proc/modules, limit text processing to 'sed'
  ...

25 files changed, 6073 insertions, 51 deletions

diff --git a/drivers/hwtracing/coresight/coresight-etm3x.c b/drivers/hwtracing/coresight/coresight-etm3x.c
index bf2476ed9356..d630b7ece735 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x.c
@@ -191,7 +191,8 @@ static void etm_set_prog(struct etm_drvdata *drvdata)
 	isb();
 	if (coresight_timeout_etm(drvdata, ETMSR, ETMSR_PROG_BIT, 1)) {
 		dev_err(drvdata->dev,
-			"timeout observed when probing at offset %#x\n", ETMSR);
+			"%s: timeout observed when probing at offset %#x\n",
+			__func__, ETMSR);
 	}
 }
 
@@ -209,7 +210,8 @@ static void etm_clr_prog(struct etm_drvdata *drvdata)
 	isb();
 	if (coresight_timeout_etm(drvdata, ETMSR, ETMSR_PROG_BIT, 0)) {
 		dev_err(drvdata->dev,
-			"timeout observed when probing at offset %#x\n", ETMSR);
+			"%s: timeout observed when probing at offset %#x\n",
+			__func__, ETMSR);
 	}
 }
 
@@ -313,14 +315,6 @@ static void etm_enable_hw(void *info)
 	dev_dbg(drvdata->dev, "cpu: %d enable smp call done\n", drvdata->cpu);
 }
 
-static int etm_trace_id_simple(struct etm_drvdata *drvdata)
-{
-	if (!drvdata->enable)
-		return drvdata->traceid;
-
-	return (etm_readl(drvdata, ETMTRACEIDR) & ETM_TRACEID_MASK);
-}
-
 static int etm_trace_id(struct coresight_device *csdev)
 {
 	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
@@ -1506,44 +1500,17 @@ static ssize_t timestamp_event_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(timestamp_event);
 
-static ssize_t status_show(struct device *dev,
-			   struct device_attribute *attr, char *buf)
+static ssize_t cpu_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
 {
-	int ret;
-	unsigned long flags;
+	int val;
 	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
 
-	pm_runtime_get_sync(drvdata->dev);
-	spin_lock_irqsave(&drvdata->spinlock, flags);
-
-	CS_UNLOCK(drvdata->base);
-	ret = sprintf(buf,
-		      "ETMCCR: 0x%08x\n"
-		      "ETMCCER: 0x%08x\n"
-		      "ETMSCR: 0x%08x\n"
-		      "ETMIDR: 0x%08x\n"
-		      "ETMCR: 0x%08x\n"
-		      "ETMTRACEIDR: 0x%08x\n"
-		      "Enable event: 0x%08x\n"
-		      "Enable start/stop: 0x%08x\n"
-		      "Enable control: CR1 0x%08x CR2 0x%08x\n"
-		      "CPU affinity: %d\n",
-		      drvdata->etmccr, drvdata->etmccer,
-		      etm_readl(drvdata, ETMSCR), etm_readl(drvdata, ETMIDR),
-		      etm_readl(drvdata, ETMCR), etm_trace_id_simple(drvdata),
-		      etm_readl(drvdata, ETMTEEVR),
-		      etm_readl(drvdata, ETMTSSCR),
-		      etm_readl(drvdata, ETMTECR1),
-		      etm_readl(drvdata, ETMTECR2),
-		      drvdata->cpu);
-	CS_LOCK(drvdata->base);
-
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
-	pm_runtime_put(drvdata->dev);
+	val = drvdata->cpu;
+	return scnprintf(buf, PAGE_SIZE, "%d\n", val);
 
-	return ret;
 }
-static DEVICE_ATTR_RO(status);
+static DEVICE_ATTR_RO(cpu);
 
 static ssize_t traceid_show(struct device *dev,
 			    struct device_attribute *attr, char *buf)
@@ -1619,11 +1586,61 @@ static struct attribute *coresight_etm_attrs[] = {
 	&dev_attr_ctxid_mask.attr,
 	&dev_attr_sync_freq.attr,
 	&dev_attr_timestamp_event.attr,
-	&dev_attr_status.attr,
 	&dev_attr_traceid.attr,
+	&dev_attr_cpu.attr,
+	NULL,
+};
+
+#define coresight_simple_func(name, offset)                             \
+static ssize_t name##_show(struct device *_dev,                         \
+			   struct device_attribute *attr, char *buf)    \
+{                                                                       \
+	struct etm_drvdata *drvdata = dev_get_drvdata(_dev->parent);    \
+	return scnprintf(buf, PAGE_SIZE, "0x%x\n",                      \
+			 readl_relaxed(drvdata->base + offset));        \
+}                                                                       \
+DEVICE_ATTR_RO(name)
+
+coresight_simple_func(etmccr, ETMCCR);
+coresight_simple_func(etmccer, ETMCCER);
+coresight_simple_func(etmscr, ETMSCR);
+coresight_simple_func(etmidr, ETMIDR);
+coresight_simple_func(etmcr, ETMCR);
+coresight_simple_func(etmtraceidr, ETMTRACEIDR);
+coresight_simple_func(etmteevr, ETMTEEVR);
+coresight_simple_func(etmtssvr, ETMTSSCR);
+coresight_simple_func(etmtecr1, ETMTECR1);
+coresight_simple_func(etmtecr2, ETMTECR2);
+
+static struct attribute *coresight_etm_mgmt_attrs[] = {
+	&dev_attr_etmccr.attr,
+	&dev_attr_etmccer.attr,
+	&dev_attr_etmscr.attr,
+	&dev_attr_etmidr.attr,
+	&dev_attr_etmcr.attr,
+	&dev_attr_etmtraceidr.attr,
+	&dev_attr_etmteevr.attr,
+	&dev_attr_etmtssvr.attr,
+	&dev_attr_etmtecr1.attr,
+	&dev_attr_etmtecr2.attr,
+	NULL,
+};
+
+static const struct attribute_group coresight_etm_group = {
+	.attrs = coresight_etm_attrs,
+};
+
+
+static const struct attribute_group coresight_etm_mgmt_group = {
+	.attrs = coresight_etm_mgmt_attrs,
+	.name = "mgmt",
+};
+
+static const struct attribute_group *coresight_etm_groups[] = {
+	&coresight_etm_group,
+	&coresight_etm_mgmt_group,
 	NULL,
 };
-ATTRIBUTE_GROUPS(coresight_etm);
 
 static int etm_cpu_callback(struct notifier_block *nfb, unsigned long action,
 			    void *hcpu)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index 254a81a4e6f4..a6707642bb23 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -136,7 +136,9 @@ static void etm4_enable_hw(void *info)
 		writel_relaxed(drvdata->cntr_val[i],
 			       drvdata->base + TRCCNTVRn(i));
 	}
-	for (i = 0; i < drvdata->nr_resource; i++)
+
+	/* Resource selector pair 0 is always implemented and reserved */
+	for (i = 2; i < drvdata->nr_resource * 2; i++)
 		writel_relaxed(drvdata->res_ctrl[i],
 			       drvdata->base + TRCRSCTLRn(i));
 
@@ -489,8 +491,9 @@ static ssize_t reset_store(struct device *dev,
 		drvdata->cntr_val[i] = 0x0;
 	}
 
-	drvdata->res_idx = 0x0;
-	for (i = 0; i < drvdata->nr_resource; i++)
+	/* Resource selector pair 0 is always implemented and reserved */
+	drvdata->res_idx = 0x2;
+	for (i = 2; i < drvdata->nr_resource * 2; i++)
 		drvdata->res_ctrl[i] = 0x0;
 
 	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
@@ -1732,7 +1735,7 @@ static ssize_t res_idx_store(struct device *dev,
 	if (kstrtoul(buf, 16, &val))
 		return -EINVAL;
 	/* Resource selector pair 0 is always implemented and reserved */
-	if ((val == 0) || (val >= drvdata->nr_resource))
+	if (val < 2 || val >= drvdata->nr_resource * 2)
 		return -EINVAL;
 
 	/*
@@ -2416,8 +2419,13 @@ static void etm4_init_arch_data(void *info)
 	drvdata->nr_addr_cmp = BMVAL(etmidr4, 0, 3);
 	/* NUMPC, bits[15:12] number of PE comparator inputs for tracing */
 	drvdata->nr_pe_cmp = BMVAL(etmidr4, 12, 15);
-	/* NUMRSPAIR, bits[19:16] the number of resource pairs for tracing */
-	drvdata->nr_resource = BMVAL(etmidr4, 16, 19);
+	/*
+	 * NUMRSPAIR, bits[19:16]
+	 * The number of resource pairs conveyed by the HW starts at 0, i.e a
+	 * value of 0x0 indicate 1 resource pair, 0x1 indicate two and so on.
+	 * As such add 1 to the value of NUMRSPAIR for a better representation.
+	 */
+	drvdata->nr_resource = BMVAL(etmidr4, 16, 19) + 1;
 	/*
 	 * NUMSSCC, bits[23:20] the number of single-shot
 	 * comparator control for tracing
@@ -2504,6 +2512,8 @@ static void etm4_init_default_data(struct etmv4_drvdata *drvdata)
 		drvdata->cntr_val[i] = 0x0;
 	}
 
+	/* Resource selector pair 0 is always implemented and reserved */
+	drvdata->res_idx = 0x2;
 	for (i = 2; i < drvdata->nr_resource * 2; i++)
 		drvdata->res_ctrl[i] = 0x0;
 
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 894531d315b8..e25492137d8b 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -240,6 +240,11 @@ static int coresight_enable_path(struct list_head *path)
 	int ret = 0;
 	struct coresight_device *cd;
 
+	/*
+	 * At this point we have a full @path, from source to sink.  The
+	 * sink is the first entry and the source the last one.  Go through
+	 * all the components and enable them one by one.
+	 */
 	list_for_each_entry(cd, path, path_link) {
 		if (cd == list_first_entry(path, struct coresight_device,
 					   path_link)) {
diff --git a/drivers/hwtracing/intel_th/Kconfig b/drivers/hwtracing/intel_th/Kconfig
new file mode 100644
index 000000000000..b7a9073d968b
--- /dev/null
+++ b/drivers/hwtracing/intel_th/Kconfig
@@ -0,0 +1,72 @@
+config INTEL_TH
+	tristate "Intel(R) Trace Hub controller"
+	help
+	  Intel(R) Trace Hub (TH) is a set of hardware blocks (subdevices) that
+	  produce, switch and output trace data from multiple hardware and
+	  software sources over several types of trace output ports encoded
+	  in System Trace Protocol (MIPI STPv2) and is intended to perform
+	  full system debugging.
+
+	  This option enables intel_th bus and common code used by TH
+	  subdevices to interact with each other and hardware and for
+	  platform glue layers to drive Intel TH devices.
+
+	  Say Y here to enable Intel(R) Trace Hub controller support.
+
+if INTEL_TH
+
+config INTEL_TH_PCI
+	tristate "Intel(R) Trace Hub PCI controller"
+	depends on PCI
+	help
+	  Intel(R) Trace Hub may exist as a PCI device. This option enables
+	  support glue layer for PCI-based Intel TH.
+
+	  Say Y here to enable PCI Intel TH support.
+
+config INTEL_TH_GTH
+	tristate "Intel(R) Trace Hub Global Trace Hub"
+	help
+	  Global Trace Hub (GTH) is the central component of the
+	  Intel TH infrastructure and acts as a switch for source
+	  and output devices. This driver is required for other
+	  Intel TH subdevices to initialize.
+
+	  Say Y here to enable GTH subdevice of Intel(R) Trace Hub.
+
+config INTEL_TH_STH
+	tristate "Intel(R) Trace Hub Software Trace Hub support"
+	depends on STM
+	help
+	  Software Trace Hub (STH) enables trace data from software
+	  trace sources to be sent out via Intel(R) Trace Hub. It
+	  uses stm class device to interface with its sources.
+
+	  Say Y here to enable STH subdevice of Intel(R) Trace Hub.
+
+config INTEL_TH_MSU
+	tristate "Intel(R) Trace Hub Memory Storage Unit"
+	help
+	  Memory Storage Unit (MSU) trace output device enables
+	  storing STP traces to system memory. It supports single
+	  and multiblock modes of operation and provides read()
+	  and mmap() access to the collected data.
+
+	  Say Y here to enable MSU output device for Intel TH.
+
+config INTEL_TH_PTI
+	tristate "Intel(R) Trace Hub PTI output"
+	help
+	  Parallel Trace Interface unit (PTI) is a trace output device
+	  of Intel TH architecture that facilitates STP trace output via
+	  a PTI port.
+
+	  Say Y to enable PTI output of Intel TH data.
+
+config INTEL_TH_DEBUG
+	bool "Intel(R) Trace Hub debugging"
+	depends on DEBUG_FS
+	help
+	  Say Y here to enable debugging.
+
+endif
diff --git a/drivers/hwtracing/intel_th/Makefile b/drivers/hwtracing/intel_th/Makefile
new file mode 100644
index 000000000000..81d42fe918f7
--- /dev/null
+++ b/drivers/hwtracing/intel_th/Makefile
@@ -0,0 +1,18 @@
+obj-$(CONFIG_INTEL_TH)		+= intel_th.o
+intel_th-y			:= core.o
+intel_th-$(CONFIG_INTEL_TH_DEBUG) += debug.o
+
+obj-$(CONFIG_INTEL_TH_PCI)	+= intel_th_pci.o
+intel_th_pci-y			:= pci.o
+
+obj-$(CONFIG_INTEL_TH_GTH)	+= intel_th_gth.o
+intel_th_gth-y			:= gth.o
+
+obj-$(CONFIG_INTEL_TH_STH)	+= intel_th_sth.o
+intel_th_sth-y			:= sth.o
+
+obj-$(CONFIG_INTEL_TH_MSU)	+= intel_th_msu.o
+intel_th_msu-y			:= msu.o
+
+obj-$(CONFIG_INTEL_TH_PTI)	+= intel_th_pti.o
+intel_th_pti-y			:= pti.o
diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c
new file mode 100644
index 000000000000..165d3001c301
--- /dev/null
+++ b/drivers/hwtracing/intel_th/core.c
@@ -0,0 +1,692 @@
+/*
+ * Intel(R) Trace Hub driver core
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/sysfs.h>
+#include <linux/kdev_t.h>
+#include <linux/debugfs.h>
+#include <linux/idr.h>
+#include <linux/pci.h>
+#include <linux/dma-mapping.h>
+
+#include "intel_th.h"
+#include "debug.h"
+
+static DEFINE_IDA(intel_th_ida);
+
+static int intel_th_match(struct device *dev, struct device_driver *driver)
+{
+	struct intel_th_driver *thdrv = to_intel_th_driver(driver);
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+
+	if (thdev->type == INTEL_TH_SWITCH &&
+	    (!thdrv->enable || !thdrv->disable))
+		return 0;
+
+	return !strcmp(thdev->name, driver->name);
+}
+
+static int intel_th_child_remove(struct device *dev, void *data)
+{
+	device_release_driver(dev);
+
+	return 0;
+}
+
+static int intel_th_probe(struct device *dev)
+{
+	struct intel_th_driver *thdrv = to_intel_th_driver(dev->driver);
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+	struct intel_th_driver *hubdrv;
+	struct intel_th_device *hub = NULL;
+	int ret;
+
+	if (thdev->type == INTEL_TH_SWITCH)
+		hub = thdev;
+	else if (dev->parent)
+		hub = to_intel_th_device(dev->parent);
+
+	if (!hub || !hub->dev.driver)
+		return -EPROBE_DEFER;
+
+	hubdrv = to_intel_th_driver(hub->dev.driver);
+
+	ret = thdrv->probe(to_intel_th_device(dev));
+	if (ret)
+		return ret;
+
+	if (thdev->type == INTEL_TH_OUTPUT &&
+	    !intel_th_output_assigned(thdev))
+		ret = hubdrv->assign(hub, thdev);
+
+	return ret;
+}
+
+static int intel_th_remove(struct device *dev)
+{
+	struct intel_th_driver *thdrv = to_intel_th_driver(dev->driver);
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+	struct intel_th_device *hub = to_intel_th_device(dev->parent);
+	int err;
+
+	if (thdev->type == INTEL_TH_SWITCH) {
+		err = device_for_each_child(dev, thdev, intel_th_child_remove);
+		if (err)
+			return err;
+	}
+
+	thdrv->remove(thdev);
+
+	if (intel_th_output_assigned(thdev)) {
+		struct intel_th_driver *hubdrv =
+			to_intel_th_driver(dev->parent->driver);
+
+		if (hub->dev.driver)
+			hubdrv->unassign(hub, thdev);
+	}
+
+	return 0;
+}
+
+static struct bus_type intel_th_bus = {
+	.name		= "intel_th",
+	.dev_attrs	= NULL,
+	.match		= intel_th_match,
+	.probe		= intel_th_probe,
+	.remove		= intel_th_remove,
+};
+
+static void intel_th_device_free(struct intel_th_device *thdev);
+
+static void intel_th_device_release(struct device *dev)
+{
+	intel_th_device_free(to_intel_th_device(dev));
+}
+
+static struct device_type intel_th_source_device_type = {
+	.name		= "intel_th_source_device",
+	.release	= intel_th_device_release,
+};
+
+static char *intel_th_output_devnode(struct device *dev, umode_t *mode,
+				     kuid_t *uid, kgid_t *gid)
+{
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+	char *node;
+
+	if (thdev->id >= 0)
+		node = kasprintf(GFP_KERNEL, "intel_th%d/%s%d", 0, thdev->name,
+				 thdev->id);
+	else
+		node = kasprintf(GFP_KERNEL, "intel_th%d/%s", 0, thdev->name);
+
+	return node;
+}
+
+static ssize_t port_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+
+	if (thdev->output.port >= 0)
+		return scnprintf(buf, PAGE_SIZE, "%u\n", thdev->output.port);
+
+	return scnprintf(buf, PAGE_SIZE, "unassigned\n");
+}
+
+static DEVICE_ATTR_RO(port);
+
+static int intel_th_output_activate(struct intel_th_device *thdev)
+{
+	struct intel_th_driver *thdrv = to_intel_th_driver(thdev->dev.driver);
+
+	if (thdrv->activate)
+		return thdrv->activate(thdev);
+
+	intel_th_trace_enable(thdev);
+
+	return 0;
+}
+
+static void intel_th_output_deactivate(struct intel_th_device *thdev)
+{
+	struct intel_th_driver *thdrv = to_intel_th_driver(thdev->dev.driver);
+
+	if (thdrv->deactivate)
+		thdrv->deactivate(thdev);
+	else
+		intel_th_trace_disable(thdev);
+}
+
+static ssize_t active_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", thdev->output.active);
+}
+
+static ssize_t active_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t size)
+{
+	struct intel_th_device *thdev = to_intel_th_device(dev);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	if (!!val != thdev->output.active) {
+		if (val)
+			ret = intel_th_output_activate(thdev);
+		else
+			intel_th_output_deactivate(thdev);
+	}
+
+	return ret ? ret : size;
+}
+
+static DEVICE_ATTR_RW(active);
+
+static struct attribute *intel_th_output_attrs[] = {
+	&dev_attr_port.attr,
+	&dev_attr_active.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(intel_th_output);
+
+static struct device_type intel_th_output_device_type = {
+	.name		= "intel_th_output_device",
+	.groups		= intel_th_output_groups,
+	.release	= intel_th_device_release,
+	.devnode	= intel_th_output_devnode,
+};
+
+static struct device_type intel_th_switch_device_type = {
+	.name		= "intel_th_switch_device",
+	.release	= intel_th_device_release,
+};
+
+static struct device_type *intel_th_device_type[] = {
+	[INTEL_TH_SOURCE]	= &intel_th_source_device_type,
+	[INTEL_TH_OUTPUT]	= &intel_th_output_device_type,
+	[INTEL_TH_SWITCH]	= &intel_th_switch_device_type,
+};
+
+int intel_th_driver_register(struct intel_th_driver *thdrv)
+{
+	if (!thdrv->probe || !thdrv->remove)
+		return -EINVAL;
+
+	thdrv->driver.bus = &intel_th_bus;
+
+	return driver_register(&thdrv->driver);
+}
+EXPORT_SYMBOL_GPL(intel_th_driver_register);
+
+void intel_th_driver_unregister(struct intel_th_driver *thdrv)
+{
+	driver_unregister(&thdrv->driver);
+}
+EXPORT_SYMBOL_GPL(intel_th_driver_unregister);
+
+static struct intel_th_device *
+intel_th_device_alloc(struct intel_th *th, unsigned int type, const char *name,
+		      int id)
+{
+	struct device *parent;
+	struct intel_th_device *thdev;
+
+	if (type == INTEL_TH_SWITCH)
+		parent = th->dev;
+	else
+		parent = &th->hub->dev;
+
+	thdev = kzalloc(sizeof(*thdev) + strlen(name) + 1, GFP_KERNEL);
+	if (!thdev)
+		return NULL;
+
+	thdev->id = id;
+	thdev->type = type;
+
+	strcpy(thdev->name, name);
+	device_initialize(&thdev->dev);
+	thdev->dev.bus = &intel_th_bus;
+	thdev->dev.type = intel_th_device_type[type];
+	thdev->dev.parent = parent;
+	thdev->dev.dma_mask = parent->dma_mask;
+	thdev->dev.dma_parms = parent->dma_parms;
+	dma_set_coherent_mask(&thdev->dev, parent->coherent_dma_mask);
+	if (id >= 0)
+		dev_set_name(&thdev->dev, "%d-%s%d", th->id, name, id);
+	else
+		dev_set_name(&thdev->dev, "%d-%s", th->id, name);
+
+	return thdev;
+}
+
+static int intel_th_device_add_resources(struct intel_th_device *thdev,
+					 struct resource *res, int nres)
+{
+	struct resource *r;
+
+	r = kmemdup(res, sizeof(*res) * nres, GFP_KERNEL);
+	if (!r)
+		return -ENOMEM;
+
+	thdev->resource = r;
+	thdev->num_resources = nres;
+
+	return 0;
+}
+
+static void intel_th_device_remove(struct intel_th_device *thdev)
+{
+	device_del(&thdev->dev);
+	put_device(&thdev->dev);
+}
+
+static void intel_th_device_free(struct intel_th_device *thdev)
+{
+	kfree(thdev->resource);
+	kfree(thdev);
+}
+
+/*
+ * Intel(R) Trace Hub subdevices
+ */
+static struct intel_th_subdevice {
+	const char		*name;
+	struct resource		res[3];
+	unsigned		nres;
+	unsigned		type;
+	unsigned		otype;
+	int			id;
+} intel_th_subdevices[TH_SUBDEVICE_MAX] = {
+	{
+		.nres	= 1,
+		.res	= {
+			{
+				.start	= REG_GTH_OFFSET,
+				.end	= REG_GTH_OFFSET + REG_GTH_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+		},
+		.name	= "gth",
+		.type	= INTEL_TH_SWITCH,
+		.id	= -1,
+	},
+	{
+		.nres	= 2,
+		.res	= {
+			{
+				.start	= REG_MSU_OFFSET,
+				.end	= REG_MSU_OFFSET + REG_MSU_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+			{
+				.start	= BUF_MSU_OFFSET,
+				.end	= BUF_MSU_OFFSET + BUF_MSU_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+		},
+		.name	= "msc",
+		.id	= 0,
+		.type	= INTEL_TH_OUTPUT,
+		.otype	= GTH_MSU,
+	},
+	{
+		.nres	= 2,
+		.res	= {
+			{
+				.start	= REG_MSU_OFFSET,
+				.end	= REG_MSU_OFFSET + REG_MSU_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+			{
+				.start	= BUF_MSU_OFFSET,
+				.end	= BUF_MSU_OFFSET + BUF_MSU_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+		},
+		.name	= "msc",
+		.id	= 1,
+		.type	= INTEL_TH_OUTPUT,
+		.otype	= GTH_MSU,
+	},
+	{
+		.nres	= 2,
+		.res	= {
+			{
+				.start	= REG_STH_OFFSET,
+				.end	= REG_STH_OFFSET + REG_STH_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+			{
+				.start	= TH_MMIO_SW,
+				.end	= 0,
+				.flags	= IORESOURCE_MEM,
+			},
+		},
+		.id	= -1,
+		.name	= "sth",
+		.type	= INTEL_TH_SOURCE,
+	},
+	{
+		.nres	= 1,
+		.res	= {
+			{
+				.start	= REG_PTI_OFFSET,
+				.end	= REG_PTI_OFFSET + REG_PTI_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+		},
+		.id	= -1,
+		.name	= "pti",
+		.type	= INTEL_TH_OUTPUT,
+		.otype	= GTH_PTI,
+	},
+	{
+		.nres	= 1,
+		.res	= {
+			{
+				.start	= REG_DCIH_OFFSET,
+				.end	= REG_DCIH_OFFSET + REG_DCIH_LENGTH - 1,
+				.flags	= IORESOURCE_MEM,
+			},
+		},
+		.id	= -1,
+		.name	= "dcih",
+		.type	= INTEL_TH_OUTPUT,
+	},
+};
+
+static int intel_th_populate(struct intel_th *th, struct resource *devres,
+			     unsigned int ndevres, int irq)
+{
+	struct resource res[3];
+	unsigned int req = 0;
+	int i, err;
+
+	/* create devices for each intel_th_subdevice */
+	for (i = 0; i < ARRAY_SIZE(intel_th_subdevices); i++) {
+		struct intel_th_subdevice *subdev = &intel_th_subdevices[i];
+		struct intel_th_device *thdev;
+		int r;
+
+		thdev = intel_th_device_alloc(th, subdev->type, subdev->name,
+					      subdev->id);
+		if (!thdev) {
+			err = -ENOMEM;
+			goto kill_subdevs;
+		}
+
+		memcpy(res, subdev->res,
+		       sizeof(struct resource) * subdev->nres);
+
+		for (r = 0; r < subdev->nres; r++) {
+			int bar = TH_MMIO_CONFIG;
+
+			/*
+			 * Take .end == 0 to mean 'take the whole bar',
+			 * .start then tells us which bar it is. Default to
+			 * TH_MMIO_CONFIG.
+			 */
+			if (!res[r].end && res[r].flags == IORESOURCE_MEM) {
+				bar = res[r].start;
+				res[r].start = 0;
+				res[r].end = resource_size(&devres[bar]) - 1;
+			}
+
+			if (res[r].flags & IORESOURCE_MEM) {
+				res[r].start	+= devres[bar].start;
+				res[r].end	+= devres[bar].start;
+
+				dev_dbg(th->dev, "%s:%d @ %pR\n",
+					subdev->name, r, &res[r]);
+			} else if (res[r].flags & IORESOURCE_IRQ) {
+				res[r].start	= irq;
+			}
+		}
+
+		err = intel_th_device_add_resources(thdev, res, subdev->nres);
+		if (err) {
+			put_device(&thdev->dev);
+			goto kill_subdevs;
+		}
+
+		if (subdev->type == INTEL_TH_OUTPUT) {
+			thdev->dev.devt = MKDEV(th->major, i);
+			thdev->output.type = subdev->otype;
+			thdev->output.port = -1;
+		}
+
+		err = device_add(&thdev->dev);
+		if (err) {
+			put_device(&thdev->dev);
+			goto kill_subdevs;
+		}
+
+		/* need switch driver to be loaded to enumerate the rest */
+		if (subdev->type == INTEL_TH_SWITCH && !req) {
+			th->hub = thdev;
+			err = request_module("intel_th_%s", subdev->name);
+			if (!err)
+				req++;
+		}
+
+		th->thdev[i] = thdev;
+	}
+
+	return 0;
+
+kill_subdevs:
+	for (i-- ; i >= 0; i--)
+		intel_th_device_remove(th->thdev[i]);
+
+	return err;
+}
+
+static int match_devt(struct device *dev, void *data)
+{
+	dev_t devt = (dev_t)(unsigned long)data;
+
+	return dev->devt == devt;
+}
+
+static int intel_th_output_open(struct inode *inode, struct file *file)
+{
+	const struct file_operations *fops;
+	struct intel_th_driver *thdrv;
+	struct device *dev;
+	int err;
+
+	dev = bus_find_device(&intel_th_bus, NULL,
+			      (void *)(unsigned long)inode->i_rdev,
+			      match_devt);
+	if (!dev || !dev->driver)
+		return -ENODEV;
+
+	thdrv = to_intel_th_driver(dev->driver);
+	fops = fops_get(thdrv->fops);
+	if (!fops)
+		return -ENODEV;
+
+	replace_fops(file, fops);
+
+	file->private_data = to_intel_th_device(dev);
+
+	if (file->f_op->open) {
+		err = file->f_op->open(inode, file);
+		return err;
+	}
+
+	return 0;
+}
+
+static const struct file_operations intel_th_output_fops = {
+	.open	= intel_th_output_open,
+	.llseek	= noop_llseek,
+};
+
+/**
+ * intel_th_alloc() - allocate a new Intel TH device and its subdevices
+ * @dev:	parent device
+ * @devres:	parent's resources
+ * @ndevres:	number of resources
+ * @irq:	irq number
+ */
+struct intel_th *
+intel_th_alloc(struct device *dev, struct resource *devres,
+	       unsigned int ndevres, int irq)
+{
+	struct intel_th *th;
+	int err;
+
+	th = kzalloc(sizeof(*th), GFP_KERNEL);
+	if (!th)
+		return ERR_PTR(-ENOMEM);
+
+	th->id = ida_simple_get(&intel_th_ida, 0, 0, GFP_KERNEL);
+	if (th->id < 0) {
+		err = th->id;
+		goto err_alloc;
+	}
+
+	th->major = __register_chrdev(0, 0, TH_POSSIBLE_OUTPUTS,
+				      "intel_th/output", &intel_th_output_fops);
+	if (th->major < 0) {
+		err = th->major;
+		goto err_ida;
+	}
+	th->dev = dev;
+
+	err = intel_th_populate(th, devres, ndevres, irq);
+	if (err)
+		goto err_chrdev;
+
+	return th;
+
+err_chrdev:
+	__unregister_chrdev(th->major, 0, TH_POSSIBLE_OUTPUTS,
+			    "intel_th/output");
+
+err_ida:
+	ida_simple_remove(&intel_th_ida, th->id);
+
+err_alloc:
+	kfree(th);
+
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(intel_th_alloc);
+
+void intel_th_free(struct intel_th *th)
+{
+	int i;
+
+	for (i = 0; i < TH_SUBDEVICE_MAX; i++)
+		if (th->thdev[i] != th->hub)
+			intel_th_device_remove(th->thdev[i]);
+
+	intel_th_device_remove(th->hub);
+
+	__unregister_chrdev(th->major, 0, TH_POSSIBLE_OUTPUTS,
+			    "intel_th/output");
+
+	ida_simple_remove(&intel_th_ida, th->id);
+
+	kfree(th);
+}
+EXPORT_SYMBOL_GPL(intel_th_free);
+
+/**
+ * intel_th_trace_enable() - enable tracing for an output device
+ * @thdev:	output device that requests tracing be enabled
+ */
+int intel_th_trace_enable(struct intel_th_device *thdev)
+{
+	struct intel_th_device *hub = to_intel_th_device(thdev->dev.parent);
+	struct intel_th_driver *hubdrv = to_intel_th_driver(hub->dev.driver);
+
+	if (WARN_ON_ONCE(hub->type != INTEL_TH_SWITCH))
+		return -EINVAL;
+
+	if (WARN_ON_ONCE(thdev->type != INTEL_TH_OUTPUT))
+		return -EINVAL;
+
+	hubdrv->enable(hub, &thdev->output);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(intel_th_trace_enable);
+
+/**
+ * intel_th_trace_disable() - disable tracing for an output device
+ * @thdev:	output device that requests tracing be disabled
+ */
+int intel_th_trace_disable(struct intel_th_device *thdev)
+{
+	struct intel_th_device *hub = to_intel_th_device(thdev->dev.parent);
+	struct intel_th_driver *hubdrv = to_intel_th_driver(hub->dev.driver);
+
+	WARN_ON_ONCE(hub->type != INTEL_TH_SWITCH);
+	if (WARN_ON_ONCE(thdev->type != INTEL_TH_OUTPUT))
+		return -EINVAL;
+
+	hubdrv->disable(hub, &thdev->output);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(intel_th_trace_disable);
+
+int intel_th_set_output(struct intel_th_device *thdev,
+			unsigned int master)
+{
+	struct intel_th_device *hub = to_intel_th_device(thdev->dev.parent);
+	struct intel_th_driver *hubdrv = to_intel_th_driver(hub->dev.driver);
+
+	if (!hubdrv->set_output)
+		return -ENOTSUPP;
+
+	return hubdrv->set_output(hub, master);
+}
+EXPORT_SYMBOL_GPL(intel_th_set_output);
+
+static int __init intel_th_init(void)
+{
+	intel_th_debug_init();
+
+	return bus_register(&intel_th_bus);
+}
+subsys_initcall(intel_th_init);
+
+static void __exit intel_th_exit(void)
+{
+	intel_th_debug_done();
+
+	bus_unregister(&intel_th_bus);
+}
+module_exit(intel_th_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel(R) Trace Hub controller driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
diff --git a/drivers/hwtracing/intel_th/debug.c b/drivers/hwtracing/intel_th/debug.c
new file mode 100644
index 000000000000..788a1f0a97ad
--- /dev/null
+++ b/drivers/hwtracing/intel_th/debug.c
@@ -0,0 +1,36 @@
+/*
+ * Intel(R) Trace Hub driver debugging
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/debugfs.h>
+
+#include "intel_th.h"
+#include "debug.h"
+
+struct dentry *intel_th_dbg;
+
+void intel_th_debug_init(void)
+{
+	intel_th_dbg = debugfs_create_dir("intel_th", NULL);
+	if (IS_ERR(intel_th_dbg))
+		intel_th_dbg = NULL;
+}
+
+void intel_th_debug_done(void)
+{
+	debugfs_remove(intel_th_dbg);
+	intel_th_dbg = NULL;
+}
diff --git a/drivers/hwtracing/intel_th/debug.h b/drivers/hwtracing/intel_th/debug.h
new file mode 100644
index 000000000000..88311bad3ba4
--- /dev/null
+++ b/drivers/hwtracing/intel_th/debug.h
@@ -0,0 +1,34 @@
+/*
+ * Intel(R) Trace Hub driver debugging
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#ifndef __INTEL_TH_DEBUG_H__
+#define __INTEL_TH_DEBUG_H__
+
+#ifdef CONFIG_INTEL_TH_DEBUG
+extern struct dentry *intel_th_dbg;
+
+void intel_th_debug_init(void);
+void intel_th_debug_done(void);
+#else
+static inline void intel_th_debug_init(void)
+{
+}
+
+static inline void intel_th_debug_done(void)
+{
+}
+#endif
+
+#endif /* __INTEL_TH_DEBUG_H__ */
diff --git a/drivers/hwtracing/intel_th/gth.c b/drivers/hwtracing/intel_th/gth.c
new file mode 100644
index 000000000000..2dc5378ccd3a
--- /dev/null
+++ b/drivers/hwtracing/intel_th/gth.c
@@ -0,0 +1,706 @@
+/*
+ * Intel(R) Trace Hub Global Trace Hub
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/bitmap.h>
+
+#include "intel_th.h"
+#include "gth.h"
+
+struct gth_device;
+
+/**
+ * struct gth_output - GTH view on an output port
+ * @gth:	backlink to the GTH device
+ * @output:	link to output device's output descriptor
+ * @index:	output port number
+ * @port_type:	one of GTH_* port type values
+ * @master:	bitmap of masters configured for this output
+ */
+struct gth_output {
+	struct gth_device	*gth;
+	struct intel_th_output	*output;
+	unsigned int		index;
+	unsigned int		port_type;
+	DECLARE_BITMAP(master, TH_CONFIGURABLE_MASTERS + 1);
+};
+
+/**
+ * struct gth_device - GTH device
+ * @dev:	driver core's device
+ * @base:	register window base address
+ * @output_group:	attributes describing output ports
+ * @master_group:	attributes describing master assignments
+ * @output:		output ports
+ * @master:		master/output port assignments
+ * @gth_lock:		serializes accesses to GTH bits
+ */
+struct gth_device {
+	struct device		*dev;
+	void __iomem		*base;
+
+	struct attribute_group	output_group;
+	struct attribute_group	master_group;
+	struct gth_output	output[TH_POSSIBLE_OUTPUTS];
+	signed char		master[TH_CONFIGURABLE_MASTERS + 1];
+	spinlock_t		gth_lock;
+};
+
+static void gth_output_set(struct gth_device *gth, int port,
+			   unsigned int config)
+{
+	unsigned long reg = port & 4 ? REG_GTH_GTHOPT1 : REG_GTH_GTHOPT0;
+	u32 val;
+	int shift = (port & 3) * 8;
+
+	val = ioread32(gth->base + reg);
+	val &= ~(0xff << shift);
+	val |= config << shift;
+	iowrite32(val, gth->base + reg);
+}
+
+static unsigned int gth_output_get(struct gth_device *gth, int port)
+{
+	unsigned long reg = port & 4 ? REG_GTH_GTHOPT1 : REG_GTH_GTHOPT0;
+	u32 val;
+	int shift = (port & 3) * 8;
+
+	val = ioread32(gth->base + reg);
+	val &= 0xff << shift;
+	val >>= shift;
+
+	return val;
+}
+
+static void gth_smcfreq_set(struct gth_device *gth, int port,
+			    unsigned int freq)
+{
+	unsigned long reg = REG_GTH_SMCR0 + ((port / 2) * 4);
+	int shift = (port & 1) * 16;
+	u32 val;
+
+	val = ioread32(gth->base + reg);
+	val &= ~(0xffff << shift);
+	val |= freq << shift;
+	iowrite32(val, gth->base + reg);
+}
+
+static unsigned int gth_smcfreq_get(struct gth_device *gth, int port)
+{
+	unsigned long reg = REG_GTH_SMCR0 + ((port / 2) * 4);
+	int shift = (port & 1) * 16;
+	u32 val;
+
+	val = ioread32(gth->base + reg);
+	val &= 0xffff << shift;
+	val >>= shift;
+
+	return val;
+}
+
+/*
+ * "masters" attribute group
+ */
+
+struct master_attribute {
+	struct device_attribute	attr;
+	struct gth_device	*gth;
+	unsigned int		master;
+};
+
+static void
+gth_master_set(struct gth_device *gth, unsigned int master, int port)
+{
+	unsigned int reg = REG_GTH_SWDEST0 + ((master >> 1) & ~3u);
+	unsigned int shift = (master & 0x7) * 4;
+	u32 val;
+
+	if (master >= 256) {
+		reg = REG_GTH_GSWTDEST;
+		shift = 0;
+	}
+
+	val = ioread32(gth->base + reg);
+	val &= ~(0xf << shift);
+	if (port >= 0)
+		val |= (0x8 | port) << shift;
+	iowrite32(val, gth->base + reg);
+}
+
+/*static int gth_master_get(struct gth_device *gth, unsigned int master)
+{
+	unsigned int reg = REG_GTH_SWDEST0 + ((master >> 1) & ~3u);
+	unsigned int shift = (master & 0x7) * 4;
+	u32 val;
+
+	if (master >= 256) {
+		reg = REG_GTH_GSWTDEST;
+		shift = 0;
+	}
+
+	val = ioread32(gth->base + reg);
+	val &= (0xf << shift);
+	val >>= shift;
+
+	return val ? val & 0x7 : -1;
+	}*/
+
+static ssize_t master_attr_show(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	struct master_attribute *ma =
+		container_of(attr, struct master_attribute, attr);
+	struct gth_device *gth = ma->gth;
+	size_t count;
+	int port;
+
+	spin_lock(&gth->gth_lock);
+	port = gth->master[ma->master];
+	spin_unlock(&gth->gth_lock);
+
+	if (port >= 0)
+		count = snprintf(buf, PAGE_SIZE, "%x\n", port);
+	else
+		count = snprintf(buf, PAGE_SIZE, "disabled\n");
+
+	return count;
+}
+
+static ssize_t master_attr_store(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *buf, size_t count)
+{
+	struct master_attribute *ma =
+		container_of(attr, struct master_attribute, attr);
+	struct gth_device *gth = ma->gth;
+	int old_port, port;
+
+	if (kstrtoint(buf, 10, &port) < 0)
+		return -EINVAL;
+
+	if (port >= TH_POSSIBLE_OUTPUTS || port < -1)
+		return -EINVAL;
+
+	spin_lock(&gth->gth_lock);
+
+	/* disconnect from the previous output port, if any */
+	old_port = gth->master[ma->master];
+	if (old_port >= 0) {
+		gth->master[ma->master] = -1;
+		clear_bit(ma->master, gth->output[old_port].master);
+		if (gth->output[old_port].output->active)
+			gth_master_set(gth, ma->master, -1);
+	}
+
+	/* connect to the new output port, if any */
+	if (port >= 0) {
+		/* check if there's a driver for this port */
+		if (!gth->output[port].output) {
+			count = -ENODEV;
+			goto unlock;
+		}
+
+		set_bit(ma->master, gth->output[port].master);
+
+		/* if the port is active, program this setting */
+		if (gth->output[port].output->active)
+			gth_master_set(gth, ma->master, port);
+	}
+
+	gth->master[ma->master] = port;
+
+unlock:
+	spin_unlock(&gth->gth_lock);
+
+	return count;
+}
+
+struct output_attribute {
+	struct device_attribute attr;
+	struct gth_device	*gth;
+	unsigned int		port;
+	unsigned int		parm;
+};
+
+#define OUTPUT_PARM(_name, _mask, _r, _w, _what)			\
+	[TH_OUTPUT_PARM(_name)] = { .name = __stringify(_name),		\
+				    .get = gth_ ## _what ## _get,	\
+				    .set = gth_ ## _what ## _set,	\
+				    .mask = (_mask),			\
+				    .readable = (_r),			\
+				    .writable = (_w) }
+
+static const struct output_parm {
+	const char	*name;
+	unsigned int	(*get)(struct gth_device *gth, int port);
+	void		(*set)(struct gth_device *gth, int port,
+			       unsigned int val);
+	unsigned int	mask;
+	unsigned int	readable : 1,
+			writable : 1;
+} output_parms[] = {
+	OUTPUT_PARM(port,	0x7,	1, 0, output),
+	OUTPUT_PARM(null,	BIT(3),	1, 1, output),
+	OUTPUT_PARM(drop,	BIT(4),	1, 1, output),
+	OUTPUT_PARM(reset,	BIT(5),	1, 0, output),
+	OUTPUT_PARM(flush,	BIT(7),	0, 1, output),
+	OUTPUT_PARM(smcfreq,	0xffff,	1, 1, smcfreq),
+};
+
+static void
+gth_output_parm_set(struct gth_device *gth, int port, unsigned int parm,
+		    unsigned int val)
+{
+	unsigned int config = output_parms[parm].get(gth, port);
+	unsigned int mask = output_parms[parm].mask;
+	unsigned int shift = __ffs(mask);
+
+	config &= ~mask;
+	config |= (val << shift) & mask;
+	output_parms[parm].set(gth, port, config);
+}
+
+static unsigned int
+gth_output_parm_get(struct gth_device *gth, int port, unsigned int parm)
+{
+	unsigned int config = output_parms[parm].get(gth, port);
+	unsigned int mask = output_parms[parm].mask;
+	unsigned int shift = __ffs(mask);
+
+	config &= mask;
+	config >>= shift;
+	return config;
+}
+
+/*
+ * Reset outputs and sources
+ */
+static int intel_th_gth_reset(struct gth_device *gth)
+{
+	u32 scratchpad;
+	int port, i;
+
+	scratchpad = ioread32(gth->base + REG_GTH_SCRPD0);
+	if (scratchpad & SCRPD_DEBUGGER_IN_USE)
+		return -EBUSY;
+
+	/* output ports */
+	for (port = 0; port < 8; port++) {
+		if (gth_output_parm_get(gth, port, TH_OUTPUT_PARM(port)) ==
+		    GTH_NONE)
+			continue;
+
+		gth_output_set(gth, port, 0);
+		gth_smcfreq_set(gth, port, 16);
+	}
+	/* disable overrides */
+	iowrite32(0, gth->base + REG_GTH_DESTOVR);
+
+	/* masters swdest_0~31 and gswdest */
+	for (i = 0; i < 33; i++)
+		iowrite32(0, gth->base + REG_GTH_SWDEST0 + i * 4);
+
+	/* sources */
+	iowrite32(0, gth->base + REG_GTH_SCR);
+	iowrite32(0xfc, gth->base + REG_GTH_SCR2);
+
+	return 0;
+}
+
+/*
+ * "outputs" attribute group
+ */
+
+static ssize_t output_attr_show(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	struct output_attribute *oa =
+		container_of(attr, struct output_attribute, attr);
+	struct gth_device *gth = oa->gth;
+	size_t count;
+
+	spin_lock(&gth->gth_lock);
+	count = snprintf(buf, PAGE_SIZE, "%x\n",
+			 gth_output_parm_get(gth, oa->port, oa->parm));
+	spin_unlock(&gth->gth_lock);
+
+	return count;
+}
+
+static ssize_t output_attr_store(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *buf, size_t count)
+{
+	struct output_attribute *oa =
+		container_of(attr, struct output_attribute, attr);
+	struct gth_device *gth = oa->gth;
+	unsigned int config;
+
+	if (kstrtouint(buf, 16, &config) < 0)
+		return -EINVAL;
+
+	spin_lock(&gth->gth_lock);
+	gth_output_parm_set(gth, oa->port, oa->parm, config);
+	spin_unlock(&gth->gth_lock);
+
+	return count;
+}
+
+static int intel_th_master_attributes(struct gth_device *gth)
+{
+	struct master_attribute *master_attrs;
+	struct attribute **attrs;
+	int i, nattrs = TH_CONFIGURABLE_MASTERS + 2;
+
+	attrs = devm_kcalloc(gth->dev, nattrs, sizeof(void *), GFP_KERNEL);
+	if (!attrs)
+		return -ENOMEM;
+
+	master_attrs = devm_kcalloc(gth->dev, nattrs,
+				    sizeof(struct master_attribute),
+				    GFP_KERNEL);
+	if (!master_attrs)
+		return -ENOMEM;
+
+	for (i = 0; i < TH_CONFIGURABLE_MASTERS + 1; i++) {
+		char *name;
+
+		name = devm_kasprintf(gth->dev, GFP_KERNEL, "%d%s", i,
+				      i == TH_CONFIGURABLE_MASTERS ? "+" : "");
+		if (!name)
+			return -ENOMEM;
+
+		master_attrs[i].attr.attr.name = name;
+		master_attrs[i].attr.attr.mode = S_IRUGO | S_IWUSR;
+		master_attrs[i].attr.show = master_attr_show;
+		master_attrs[i].attr.store = master_attr_store;
+
+		sysfs_attr_init(&master_attrs[i].attr.attr);
+		attrs[i] = &master_attrs[i].attr.attr;
+
+		master_attrs[i].gth = gth;
+		master_attrs[i].master = i;
+	}
+
+	gth->master_group.name	= "masters";
+	gth->master_group.attrs = attrs;
+
+	return sysfs_create_group(&gth->dev->kobj, &gth->master_group);
+}
+
+static int intel_th_output_attributes(struct gth_device *gth)
+{
+	struct output_attribute *out_attrs;
+	struct attribute **attrs;
+	int i, j, nouts = TH_POSSIBLE_OUTPUTS;
+	int nparms = ARRAY_SIZE(output_parms);
+	int nattrs = nouts * nparms + 1;
+
+	attrs = devm_kcalloc(gth->dev, nattrs, sizeof(void *), GFP_KERNEL);
+	if (!attrs)
+		return -ENOMEM;
+
+	out_attrs = devm_kcalloc(gth->dev, nattrs,
+				 sizeof(struct output_attribute),
+				 GFP_KERNEL);
+	if (!out_attrs)
+		return -ENOMEM;
+
+	for (i = 0; i < nouts; i++) {
+		for (j = 0; j < nparms; j++) {
+			unsigned int idx = i * nparms + j;
+			char *name;
+
+			name = devm_kasprintf(gth->dev, GFP_KERNEL, "%d_%s", i,
+					      output_parms[j].name);
+			if (!name)
+				return -ENOMEM;
+
+			out_attrs[idx].attr.attr.name = name;
+
+			if (output_parms[j].readable) {
+				out_attrs[idx].attr.attr.mode |= S_IRUGO;
+				out_attrs[idx].attr.show = output_attr_show;
+			}
+
+			if (output_parms[j].writable) {
+				out_attrs[idx].attr.attr.mode |= S_IWUSR;
+				out_attrs[idx].attr.store = output_attr_store;
+			}
+
+			sysfs_attr_init(&out_attrs[idx].attr.attr);
+			attrs[idx] = &out_attrs[idx].attr.attr;
+
+			out_attrs[idx].gth = gth;
+			out_attrs[idx].port = i;
+			out_attrs[idx].parm = j;
+		}
+	}
+
+	gth->output_group.name	= "outputs";
+	gth->output_group.attrs = attrs;
+
+	return sysfs_create_group(&gth->dev->kobj, &gth->output_group);
+}
+
+/**
+ * intel_th_gth_disable() - enable tracing to an output device
+ * @thdev:	GTH device
+ * @output:	output device's descriptor
+ *
+ * This will deconfigure all masters set to output to this device,
+ * disable tracing using force storeEn off signal and wait for the
+ * "pipeline empty" bit for corresponding output port.
+ */
+static void intel_th_gth_disable(struct intel_th_device *thdev,
+				 struct intel_th_output *output)
+{
+	struct gth_device *gth = dev_get_drvdata(&thdev->dev);
+	unsigned long count;
+	int master;
+	u32 reg;
+
+	spin_lock(&gth->gth_lock);
+	output->active = false;
+
+	for_each_set_bit(master, gth->output[output->port].master,
+			 TH_CONFIGURABLE_MASTERS) {
+		gth_master_set(gth, master, -1);
+	}
+	spin_unlock(&gth->gth_lock);
+
+	iowrite32(0, gth->base + REG_GTH_SCR);
+	iowrite32(0xfd, gth->base + REG_GTH_SCR2);
+
+	/* wait on pipeline empty for the given port */
+	for (reg = 0, count = GTH_PLE_WAITLOOP_DEPTH;
+	     count && !(reg & BIT(output->port)); count--) {
+		reg = ioread32(gth->base + REG_GTH_STAT);
+		cpu_relax();
+	}
+
+	/* clear force capture done for next captures */
+	iowrite32(0xfc, gth->base + REG_GTH_SCR2);
+
+	if (!count)
+		dev_dbg(&thdev->dev, "timeout waiting for GTH[%d] PLE\n",
+			output->port);
+}
+
+/**
+ * intel_th_gth_enable() - enable tracing to an output device
+ * @thdev:	GTH device
+ * @output:	output device's descriptor
+ *
+ * This will configure all masters set to output to this device and
+ * enable tracing using force storeEn signal.
+ */
+static void intel_th_gth_enable(struct intel_th_device *thdev,
+				struct intel_th_output *output)
+{
+	struct gth_device *gth = dev_get_drvdata(&thdev->dev);
+	u32 scr = 0xfc0000;
+	int master;
+
+	spin_lock(&gth->gth_lock);
+	for_each_set_bit(master, gth->output[output->port].master,
+			 TH_CONFIGURABLE_MASTERS + 1) {
+		gth_master_set(gth, master, output->port);
+	}
+
+	if (output->multiblock)
+		scr |= 0xff;
+
+	output->active = true;
+	spin_unlock(&gth->gth_lock);
+
+	iowrite32(scr, gth->base + REG_GTH_SCR);
+	iowrite32(0, gth->base + REG_GTH_SCR2);
+}
+
+/**
+ * intel_th_gth_assign() - assign output device to a GTH output port
+ * @thdev:	GTH device
+ * @othdev:	output device
+ *
+ * This will match a given output device parameters against present
+ * output ports on the GTH and fill out relevant bits in output device's
+ * descriptor.
+ *
+ * Return:	0 on success, -errno on error.
+ */
+static int intel_th_gth_assign(struct intel_th_device *thdev,
+			       struct intel_th_device *othdev)
+{
+	struct gth_device *gth = dev_get_drvdata(&thdev->dev);
+	int i, id;
+
+	if (othdev->type != INTEL_TH_OUTPUT)
+		return -EINVAL;
+
+	for (i = 0, id = 0; i < TH_POSSIBLE_OUTPUTS; i++) {
+		if (gth->output[i].port_type != othdev->output.type)
+			continue;
+
+		if (othdev->id == -1 || othdev->id == id)
+			goto found;
+
+		id++;
+	}
+
+	return -ENOENT;
+
+found:
+	spin_lock(&gth->gth_lock);
+	othdev->output.port = i;
+	othdev->output.active = false;
+	gth->output[i].output = &othdev->output;
+	spin_unlock(&gth->gth_lock);
+
+	return 0;
+}
+
+/**
+ * intel_th_gth_unassign() - deassociate an output device from its output port
+ * @thdev:	GTH device
+ * @othdev:	output device
+ */
+static void intel_th_gth_unassign(struct intel_th_device *thdev,
+				  struct intel_th_device *othdev)
+{
+	struct gth_device *gth = dev_get_drvdata(&thdev->dev);
+	int port = othdev->output.port;
+
+	spin_lock(&gth->gth_lock);
+	othdev->output.port = -1;
+	othdev->output.active = false;
+	gth->output[port].output = NULL;
+	spin_unlock(&gth->gth_lock);
+}
+
+static int
+intel_th_gth_set_output(struct intel_th_device *thdev, unsigned int master)
+{
+	struct gth_device *gth = dev_get_drvdata(&thdev->dev);
+	int port = 0; /* FIXME: make default output configurable */
+
+	/*
+	 * everything above TH_CONFIGURABLE_MASTERS is controlled by the
+	 * same register
+	 */
+	if (master > TH_CONFIGURABLE_MASTERS)
+		master = TH_CONFIGURABLE_MASTERS;
+
+	spin_lock(&gth->gth_lock);
+	if (gth->master[master] == -1) {
+		set_bit(master, gth->output[port].master);
+		gth->master[master] = port;
+	}
+	spin_unlock(&gth->gth_lock);
+
+	return 0;
+}
+
+static int intel_th_gth_probe(struct intel_th_device *thdev)
+{
+	struct device *dev = &thdev->dev;
+	struct gth_device *gth;
+	struct resource *res;
+	void __iomem *base;
+	int i, ret;
+
+	res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	base = devm_ioremap(dev, res->start, resource_size(res));
+	if (!base)
+		return -ENOMEM;
+
+	gth = devm_kzalloc(dev, sizeof(*gth), GFP_KERNEL);
+	if (!gth)
+		return -ENOMEM;
+
+	gth->dev = dev;
+	gth->base = base;
+	spin_lock_init(&gth->gth_lock);
+
+	ret = intel_th_gth_reset(gth);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < TH_CONFIGURABLE_MASTERS + 1; i++)
+		gth->master[i] = -1;
+
+	for (i = 0; i < TH_POSSIBLE_OUTPUTS; i++) {
+		gth->output[i].gth = gth;
+		gth->output[i].index = i;
+		gth->output[i].port_type =
+			gth_output_parm_get(gth, i, TH_OUTPUT_PARM(port));
+	}
+
+	if (intel_th_output_attributes(gth) ||
+	    intel_th_master_attributes(gth)) {
+		pr_warn("Can't initialize sysfs attributes\n");
+
+		if (gth->output_group.attrs)
+			sysfs_remove_group(&gth->dev->kobj, &gth->output_group);
+		return -ENOMEM;
+	}
+
+	dev_set_drvdata(dev, gth);
+
+	return 0;
+}
+
+static void intel_th_gth_remove(struct intel_th_device *thdev)
+{
+	struct gth_device *gth = dev_get_drvdata(&thdev->dev);
+
+	sysfs_remove_group(&gth->dev->kobj, &gth->output_group);
+	sysfs_remove_group(&gth->dev->kobj, &gth->master_group);
+}
+
+static struct intel_th_driver intel_th_gth_driver = {
+	.probe		= intel_th_gth_probe,
+	.remove		= intel_th_gth_remove,
+	.assign		= intel_th_gth_assign,
+	.unassign	= intel_th_gth_unassign,
+	.set_output	= intel_th_gth_set_output,
+	.enable		= intel_th_gth_enable,
+	.disable	= intel_th_gth_disable,
+	.driver	= {
+		.name	= "gth",
+		.owner	= THIS_MODULE,
+	},
+};
+
+module_driver(intel_th_gth_driver,
+	      intel_th_driver_register,
+	      intel_th_driver_unregister);
+
+MODULE_ALIAS("intel_th_switch");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel(R) Trace Hub Global Trace Hub driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
diff --git a/drivers/hwtracing/intel_th/gth.h b/drivers/hwtracing/intel_th/gth.h
new file mode 100644
index 000000000000..3b714b7a61db
--- /dev/null
+++ b/drivers/hwtracing/intel_th/gth.h
@@ -0,0 +1,66 @@
+/*
+ * Intel(R) Trace Hub Global Trace Hub (GTH) data structures
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#ifndef __INTEL_TH_GTH_H__
+#define __INTEL_TH_GTH_H__
+
+/* Map output port parameter bits to symbolic names */
+#define TH_OUTPUT_PARM(name)			\
+	TH_OUTPUT_ ## name
+
+enum intel_th_output_parm {
+	/* output port type */
+	TH_OUTPUT_PARM(port),
+	/* generate NULL packet */
+	TH_OUTPUT_PARM(null),
+	/* packet drop */
+	TH_OUTPUT_PARM(drop),
+	/* port in reset state */
+	TH_OUTPUT_PARM(reset),
+	/* flush out data */
+	TH_OUTPUT_PARM(flush),
+	/* mainenance packet frequency */
+	TH_OUTPUT_PARM(smcfreq),
+};
+
+/*
+ * Register offsets
+ */
+enum {
+	REG_GTH_GTHOPT0		= 0x00, /* Output ports 0..3 config */
+	REG_GTH_GTHOPT1		= 0x04, /* Output ports 4..7 config */
+	REG_GTH_SWDEST0		= 0x08, /* Switching destination masters 0..7 */
+	REG_GTH_GSWTDEST	= 0x88, /* Global sw trace destination */
+	REG_GTH_SMCR0		= 0x9c, /* STP mainenance for ports 0/1 */
+	REG_GTH_SMCR1		= 0xa0, /* STP mainenance for ports 2/3 */
+	REG_GTH_SMCR2		= 0xa4, /* STP mainenance for ports 4/5 */
+	REG_GTH_SMCR3		= 0xa8, /* STP mainenance for ports 6/7 */
+	REG_GTH_SCR		= 0xc8, /* Source control (storeEn override) */
+	REG_GTH_STAT		= 0xd4, /* GTH status */
+	REG_GTH_SCR2		= 0xd8, /* Source control (force storeEn off) */
+	REG_GTH_DESTOVR		= 0xdc, /* Destination override */
+	REG_GTH_SCRPD0		= 0xe0, /* ScratchPad[0] */
+	REG_GTH_SCRPD1		= 0xe4, /* ScratchPad[1] */
+	REG_GTH_SCRPD2		= 0xe8, /* ScratchPad[2] */
+	REG_GTH_SCRPD3		= 0xec, /* ScratchPad[3] */
+};
+
+/* Externall debugger is using Intel TH */
+#define SCRPD_DEBUGGER_IN_USE	BIT(24)
+
+/* waiting for Pipeline Empty bit(s) to assert for GTH */
+#define GTH_PLE_WAITLOOP_DEPTH	10000
+
+#endif /* __INTEL_TH_GTH_H__ */
diff --git a/drivers/hwtracing/intel_th/intel_th.h b/drivers/hwtracing/intel_th/intel_th.h
new file mode 100644
index 000000000000..57fd72b20fae
--- /dev/null
+++ b/drivers/hwtracing/intel_th/intel_th.h
@@ -0,0 +1,244 @@
+/*
+ * Intel(R) Trace Hub data structures
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#ifndef __INTEL_TH_H__
+#define __INTEL_TH_H__
+
+/* intel_th_device device types */
+enum {
+	/* Devices that generate trace data */
+	INTEL_TH_SOURCE = 0,
+	/* Output ports (MSC, PTI) */
+	INTEL_TH_OUTPUT,
+	/* Switch, the Global Trace Hub (GTH) */
+	INTEL_TH_SWITCH,
+};
+
+/**
+ * struct intel_th_output - descriptor INTEL_TH_OUTPUT type devices
+ * @port:	output port number, assigned by the switch
+ * @type:	GTH_{MSU,CTP,PTI}
+ * @multiblock:	true for multiblock output configuration
+ * @active:	true when this output is enabled
+ *
+ * Output port descriptor, used by switch driver to tell which output
+ * port this output device corresponds to. Filled in at output device's
+ * probe time by switch::assign(). Passed from output device driver to
+ * switch related code to enable/disable its port.
+ */
+struct intel_th_output {
+	int		port;
+	unsigned int	type;
+	bool		multiblock;
+	bool		active;
+};
+
+/**
+ * struct intel_th_device - device on the intel_th bus
+ * @dev:		device
+ * @resource:		array of resources available to this device
+ * @num_resources:	number of resources in @resource array
+ * @type:		INTEL_TH_{SOURCE,OUTPUT,SWITCH}
+ * @id:			device instance or -1
+ * @output:		output descriptor for INTEL_TH_OUTPUT devices
+ * @name:		device name to match the driver
+ */
+struct intel_th_device {
+	struct device	dev;
+	struct resource	*resource;
+	unsigned int	num_resources;
+	unsigned int	type;
+	int		id;
+
+	/* INTEL_TH_OUTPUT specific */
+	struct intel_th_output	output;
+
+	char		name[];
+};
+
+#define to_intel_th_device(_d)				\
+	container_of((_d), struct intel_th_device, dev)
+
+/**
+ * intel_th_device_get_resource() - obtain @num'th resource of type @type
+ * @thdev:	the device to search the resource for
+ * @type:	resource type
+ * @num:	number of the resource
+ */
+static inline struct resource *
+intel_th_device_get_resource(struct intel_th_device *thdev, unsigned int type,
+			     unsigned int num)
+{
+	int i;
+
+	for (i = 0; i < thdev->num_resources; i++)
+		if (resource_type(&thdev->resource[i]) == type && !num--)
+			return &thdev->resource[i];
+
+	return NULL;
+}
+
+/**
+ * intel_th_output_assigned() - if an output device is assigned to a switch port
+ * @thdev:	the output device
+ *
+ * Return:	true if the device is INTEL_TH_OUTPUT *and* is assigned a port
+ */
+static inline bool
+intel_th_output_assigned(struct intel_th_device *thdev)
+{
+	return thdev->type == INTEL_TH_OUTPUT &&
+		thdev->output.port >= 0;
+}
+
+/**
+ * struct intel_th_driver - driver for an intel_th_device device
+ * @driver:	generic driver
+ * @probe:	probe method
+ * @remove:	remove method
+ * @assign:	match a given output type device against available outputs
+ * @unassign:	deassociate an output type device from an output port
+ * @enable:	enable tracing for a given output device
+ * @disable:	disable tracing for a given output device
+ * @fops:	file operations for device nodes
+ *
+ * Callbacks @probe and @remove are required for all device types.
+ * Switch device driver needs to fill in @assign, @enable and @disable
+ * callbacks.
+ */
+struct intel_th_driver {
+	struct device_driver	driver;
+	int			(*probe)(struct intel_th_device *thdev);
+	void			(*remove)(struct intel_th_device *thdev);
+	/* switch (GTH) ops */
+	int			(*assign)(struct intel_th_device *thdev,
+					  struct intel_th_device *othdev);
+	void			(*unassign)(struct intel_th_device *thdev,
+					    struct intel_th_device *othdev);
+	void			(*enable)(struct intel_th_device *thdev,
+					  struct intel_th_output *output);
+	void			(*disable)(struct intel_th_device *thdev,
+					   struct intel_th_output *output);
+	/* output ops */
+	void			(*irq)(struct intel_th_device *thdev);
+	int			(*activate)(struct intel_th_device *thdev);
+	void			(*deactivate)(struct intel_th_device *thdev);
+	/* file_operations for those who want a device node */
+	const struct file_operations *fops;
+
+	/* source ops */
+	int			(*set_output)(struct intel_th_device *thdev,
+					      unsigned int master);
+};
+
+#define to_intel_th_driver(_d)					\
+	container_of((_d), struct intel_th_driver, driver)
+
+static inline struct intel_th_device *
+to_intel_th_hub(struct intel_th_device *thdev)
+{
+	struct device *parent = thdev->dev.parent;
+
+	if (!parent)
+		return NULL;
+
+	return to_intel_th_device(parent);
+}
+
+struct intel_th *
+intel_th_alloc(struct device *dev, struct resource *devres,
+	       unsigned int ndevres, int irq);
+void intel_th_free(struct intel_th *th);
+
+int intel_th_driver_register(struct intel_th_driver *thdrv);
+void intel_th_driver_unregister(struct intel_th_driver *thdrv);
+
+int intel_th_trace_enable(struct intel_th_device *thdev);
+int intel_th_trace_disable(struct intel_th_device *thdev);
+int intel_th_set_output(struct intel_th_device *thdev,
+			unsigned int master);
+
+enum {
+	TH_MMIO_CONFIG = 0,
+	TH_MMIO_SW = 2,
+	TH_MMIO_END,
+};
+
+#define TH_SUBDEVICE_MAX	6
+#define TH_POSSIBLE_OUTPUTS	8
+#define TH_CONFIGURABLE_MASTERS 256
+#define TH_MSC_MAX		2
+
+/**
+ * struct intel_th - Intel TH controller
+ * @dev:	driver core's device
+ * @thdev:	subdevices
+ * @hub:	"switch" subdevice (GTH)
+ * @id:		this Intel TH controller's device ID in the system
+ * @major:	device node major for output devices
+ */
+struct intel_th {
+	struct device		*dev;
+
+	struct intel_th_device	*thdev[TH_SUBDEVICE_MAX];
+	struct intel_th_device	*hub;
+
+	int			id;
+	int			major;
+#ifdef CONFIG_INTEL_TH_DEBUG
+	struct dentry		*dbg;
+#endif
+};
+
+/*
+ * Register windows
+ */
+enum {
+	/* Global Trace Hub (GTH) */
+	REG_GTH_OFFSET		= 0x0000,
+	REG_GTH_LENGTH		= 0x2000,
+
+	/* Software Trace Hub (STH) [0x4000..0x4fff] */
+	REG_STH_OFFSET		= 0x4000,
+	REG_STH_LENGTH		= 0x2000,
+
+	/* Memory Storage Unit (MSU) [0xa0000..0xa1fff] */
+	REG_MSU_OFFSET		= 0xa0000,
+	REG_MSU_LENGTH		= 0x02000,
+
+	/* Internal MSU trace buffer [0x80000..0x9ffff] */
+	BUF_MSU_OFFSET		= 0x80000,
+	BUF_MSU_LENGTH		= 0x20000,
+
+	/* PTI output == same window as GTH */
+	REG_PTI_OFFSET		= REG_GTH_OFFSET,
+	REG_PTI_LENGTH		= REG_GTH_LENGTH,
+
+	/* DCI Handler (DCIH) == some window as MSU */
+	REG_DCIH_OFFSET		= REG_MSU_OFFSET,
+	REG_DCIH_LENGTH		= REG_MSU_LENGTH,
+};
+
+/*
+ * GTH, output ports configuration
+ */
+enum {
+	GTH_NONE = 0,
+	GTH_MSU,	/* memory/usb */
+	GTH_CTP,	/* Common Trace Port */
+	GTH_PTI = 4,	/* MIPI-PTI */
+};
+
+#endif
diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c
new file mode 100644
index 000000000000..70ca27e45602
--- /dev/null
+++ b/drivers/hwtracing/intel_th/msu.c
@@ -0,0 +1,1509 @@
+/*
+ * Intel(R) Trace Hub Memory Storage Unit
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/uaccess.h>
+#include <linux/sizes.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/io.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/cacheflush.h>
+
+#include "intel_th.h"
+#include "msu.h"
+
+#define msc_dev(x) (&(x)->thdev->dev)
+
+/**
+ * struct msc_block - multiblock mode block descriptor
+ * @bdesc:	pointer to hardware descriptor (beginning of the block)
+ * @addr:	physical address of the block
+ */
+struct msc_block {
+	struct msc_block_desc	*bdesc;
+	dma_addr_t		addr;
+};
+
+/**
+ * struct msc_window - multiblock mode window descriptor
+ * @entry:	window list linkage (msc::win_list)
+ * @pgoff:	page offset into the buffer that this window starts at
+ * @nr_blocks:	number of blocks (pages) in this window
+ * @block:	array of block descriptors
+ */
+struct msc_window {
+	struct list_head	entry;
+	unsigned long		pgoff;
+	unsigned int		nr_blocks;
+	struct msc		*msc;
+	struct msc_block	block[0];
+};
+
+/**
+ * struct msc_iter - iterator for msc buffer
+ * @entry:		msc::iter_list linkage
+ * @msc:		pointer to the MSC device
+ * @start_win:		oldest window
+ * @win:		current window
+ * @offset:		current logical offset into the buffer
+ * @start_block:	oldest block in the window
+ * @block:		block number in the window
+ * @block_off:		offset into current block
+ * @wrap_count:		block wrapping handling
+ * @eof:		end of buffer reached
+ */
+struct msc_iter {
+	struct list_head	entry;
+	struct msc		*msc;
+	struct msc_window	*start_win;
+	struct msc_window	*win;
+	unsigned long		offset;
+	int			start_block;
+	int			block;
+	unsigned int		block_off;
+	unsigned int		wrap_count;
+	unsigned int		eof;
+};
+
+/**
+ * struct msc - MSC device representation
+ * @reg_base:		register window base address
+ * @thdev:		intel_th_device pointer
+ * @win_list:		list of windows in multiblock mode
+ * @nr_pages:		total number of pages allocated for this buffer
+ * @single_sz:		amount of data in single mode
+ * @single_wrap:	single mode wrap occurred
+ * @base:		buffer's base pointer
+ * @base_addr:		buffer's base address
+ * @user_count:		number of users of the buffer
+ * @mmap_count:		number of mappings
+ * @buf_mutex:		mutex to serialize access to buffer-related bits
+
+ * @enabled:		MSC is enabled
+ * @wrap:		wrapping is enabled
+ * @mode:		MSC operating mode
+ * @burst_len:		write burst length
+ * @index:		number of this MSC in the MSU
+ */
+struct msc {
+	void __iomem		*reg_base;
+	struct intel_th_device	*thdev;
+
+	struct list_head	win_list;
+	unsigned long		nr_pages;
+	unsigned long		single_sz;
+	unsigned int		single_wrap : 1;
+	void			*base;
+	dma_addr_t		base_addr;
+
+	/* <0: no buffer, 0: no users, >0: active users */
+	atomic_t		user_count;
+
+	atomic_t		mmap_count;
+	struct mutex		buf_mutex;
+
+	struct mutex		iter_mutex;
+	struct list_head	iter_list;
+
+	/* config */
+	unsigned int		enabled : 1,
+				wrap	: 1;
+	unsigned int		mode;
+	unsigned int		burst_len;
+	unsigned int		index;
+};
+
+static inline bool msc_block_is_empty(struct msc_block_desc *bdesc)
+{
+	/* header hasn't been written */
+	if (!bdesc->valid_dw)
+		return true;
+
+	/* valid_dw includes the header */
+	if (!msc_data_sz(bdesc))
+		return true;
+
+	return false;
+}
+
+/**
+ * msc_oldest_window() - locate the window with oldest data
+ * @msc:	MSC device
+ *
+ * This should only be used in multiblock mode. Caller should hold the
+ * msc::user_count reference.
+ *
+ * Return:	the oldest window with valid data
+ */
+static struct msc_window *msc_oldest_window(struct msc *msc)
+{
+	struct msc_window *win;
+	u32 reg = ioread32(msc->reg_base + REG_MSU_MSC0NWSA);
+	unsigned long win_addr = (unsigned long)reg << PAGE_SHIFT;
+	unsigned int found = 0;
+
+	if (list_empty(&msc->win_list))
+		return NULL;
+
+	/*
+	 * we might need a radix tree for this, depending on how
+	 * many windows a typical user would allocate; ideally it's
+	 * something like 2, in which case we're good
+	 */
+	list_for_each_entry(win, &msc->win_list, entry) {
+		if (win->block[0].addr == win_addr)
+			found++;
+
+		/* skip the empty ones */
+		if (msc_block_is_empty(win->block[0].bdesc))
+			continue;
+
+		if (found)
+			return win;
+	}
+
+	return list_entry(msc->win_list.next, struct msc_window, entry);
+}
+
+/**
+ * msc_win_oldest_block() - locate the oldest block in a given window
+ * @win:	window to look at
+ *
+ * Return:	index of the block with the oldest data
+ */
+static unsigned int msc_win_oldest_block(struct msc_window *win)
+{
+	unsigned int blk;
+	struct msc_block_desc *bdesc = win->block[0].bdesc;
+
+	/* without wrapping, first block is the oldest */
+	if (!msc_block_wrapped(bdesc))
+		return 0;
+
+	/*
+	 * with wrapping, last written block contains both the newest and the
+	 * oldest data for this window.
+	 */
+	for (blk = 0; blk < win->nr_blocks; blk++) {
+		bdesc = win->block[blk].bdesc;
+
+		if (msc_block_last_written(bdesc))
+			return blk;
+	}
+
+	return 0;
+}
+
+/**
+ * msc_is_last_win() - check if a window is the last one for a given MSC
+ * @win:	window
+ * Return:	true if @win is the last window in MSC's multiblock buffer
+ */
+static inline bool msc_is_last_win(struct msc_window *win)
+{
+	return win->entry.next == &win->msc->win_list;
+}
+
+/**
+ * msc_next_window() - return next window in the multiblock buffer
+ * @win:	current window
+ *
+ * Return:	window following the current one
+ */
+static struct msc_window *msc_next_window(struct msc_window *win)
+{
+	if (msc_is_last_win(win))
+		return list_entry(win->msc->win_list.next, struct msc_window,
+				  entry);
+
+	return list_entry(win->entry.next, struct msc_window, entry);
+}
+
+static struct msc_block_desc *msc_iter_bdesc(struct msc_iter *iter)
+{
+	return iter->win->block[iter->block].bdesc;
+}
+
+static void msc_iter_init(struct msc_iter *iter)
+{
+	memset(iter, 0, sizeof(*iter));
+	iter->start_block = -1;
+	iter->block = -1;
+}
+
+static struct msc_iter *msc_iter_install(struct msc *msc)
+{
+	struct msc_iter *iter;
+
+	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+	if (!iter)
+		return NULL;
+
+	msc_iter_init(iter);
+	iter->msc = msc;
+
+	mutex_lock(&msc->iter_mutex);
+	list_add_tail(&iter->entry, &msc->iter_list);
+	mutex_unlock(&msc->iter_mutex);
+
+	return iter;
+}
+
+static void msc_iter_remove(struct msc_iter *iter, struct msc *msc)
+{
+	mutex_lock(&msc->iter_mutex);
+	list_del(&iter->entry);
+	mutex_unlock(&msc->iter_mutex);
+
+	kfree(iter);
+}
+
+static void msc_iter_block_start(struct msc_iter *iter)
+{
+	if (iter->start_block != -1)
+		return;
+
+	iter->start_block = msc_win_oldest_block(iter->win);
+	iter->block = iter->start_block;
+	iter->wrap_count = 0;
+
+	/*
+	 * start with the block with oldest data; if data has wrapped
+	 * in this window, it should be in this block
+	 */
+	if (msc_block_wrapped(msc_iter_bdesc(iter)))
+		iter->wrap_count = 2;
+
+}
+
+static int msc_iter_win_start(struct msc_iter *iter, struct msc *msc)
+{
+	/* already started, nothing to do */
+	if (iter->start_win)
+		return 0;
+
+	iter->start_win = msc_oldest_window(msc);
+	if (!iter->start_win)
+		return -EINVAL;
+
+	iter->win = iter->start_win;
+	iter->start_block = -1;
+
+	msc_iter_block_start(iter);
+
+	return 0;
+}
+
+static int msc_iter_win_advance(struct msc_iter *iter)
+{
+	iter->win = msc_next_window(iter->win);
+	iter->start_block = -1;
+
+	if (iter->win == iter->start_win) {
+		iter->eof++;
+		return 1;
+	}
+
+	msc_iter_block_start(iter);
+
+	return 0;
+}
+
+static int msc_iter_block_advance(struct msc_iter *iter)
+{
+	iter->block_off = 0;
+
+	/* wrapping */
+	if (iter->wrap_count && iter->block == iter->start_block) {
+		iter->wrap_count--;
+		if (!iter->wrap_count)
+			/* copied newest data from the wrapped block */
+			return msc_iter_win_advance(iter);
+	}
+
+	/* no wrapping, check for last written block */
+	if (!iter->wrap_count && msc_block_last_written(msc_iter_bdesc(iter)))
+		/* copied newest data for the window */
+		return msc_iter_win_advance(iter);
+
+	/* block advance */
+	if (++iter->block == iter->win->nr_blocks)
+		iter->block = 0;
+
+	/* no wrapping, sanity check in case there is no last written block */
+	if (!iter->wrap_count && iter->block == iter->start_block)
+		return msc_iter_win_advance(iter);
+
+	return 0;
+}
+
+/**
+ * msc_buffer_iterate() - go through multiblock buffer's data
+ * @iter:	iterator structure
+ * @size:	amount of data to scan
+ * @data:	callback's private data
+ * @fn:		iterator callback
+ *
+ * This will start at the window which will be written to next (containing
+ * the oldest data) and work its way to the current window, calling @fn
+ * for each chunk of data as it goes.
+ *
+ * Caller should have msc::user_count reference to make sure the buffer
+ * doesn't disappear from under us.
+ *
+ * Return:	amount of data actually scanned.
+ */
+static ssize_t
+msc_buffer_iterate(struct msc_iter *iter, size_t size, void *data,
+		   unsigned long (*fn)(void *, void *, size_t))
+{
+	struct msc *msc = iter->msc;
+	size_t len = size;
+	unsigned int advance;
+
+	if (iter->eof)
+		return 0;
+
+	/* start with the oldest window */
+	if (msc_iter_win_start(iter, msc))
+		return 0;
+
+	do {
+		unsigned long data_bytes = msc_data_sz(msc_iter_bdesc(iter));
+		void *src = (void *)msc_iter_bdesc(iter) + MSC_BDESC;
+		size_t tocopy = data_bytes, copied = 0;
+		size_t remaining = 0;
+
+		advance = 1;
+
+		/*
+		 * If block wrapping happened, we need to visit the last block
+		 * twice, because it contains both the oldest and the newest
+		 * data in this window.
+		 *
+		 * First time (wrap_count==2), in the very beginning, to collect
+		 * the oldest data, which is in the range
+		 * (data_bytes..DATA_IN_PAGE).
+		 *
+		 * Second time (wrap_count==1), it's just like any other block,
+		 * containing data in the range of [MSC_BDESC..data_bytes].
+		 */
+		if (iter->block == iter->start_block && iter->wrap_count) {
+			tocopy = DATA_IN_PAGE - data_bytes;
+			src += data_bytes;
+		}
+
+		if (!tocopy)
+			goto next_block;
+
+		tocopy -= iter->block_off;
+		src += iter->block_off;
+
+		if (len < tocopy) {
+			tocopy = len;
+			advance = 0;
+		}
+
+		remaining = fn(data, src, tocopy);
+
+		if (remaining)
+			advance = 0;
+
+		copied = tocopy - remaining;
+		len -= copied;
+		iter->block_off += copied;
+		iter->offset += copied;
+
+		if (!advance)
+			break;
+
+next_block:
+		if (msc_iter_block_advance(iter))
+			break;
+
+	} while (len);
+
+	return size - len;
+}
+
+/**
+ * msc_buffer_clear_hw_header() - clear hw header for multiblock
+ * @msc:	MSC device
+ */
+static void msc_buffer_clear_hw_header(struct msc *msc)
+{
+	struct msc_window *win;
+
+	mutex_lock(&msc->buf_mutex);
+	list_for_each_entry(win, &msc->win_list, entry) {
+		unsigned int blk;
+		size_t hw_sz = sizeof(struct msc_block_desc) -
+			offsetof(struct msc_block_desc, hw_tag);
+
+		for (blk = 0; blk < win->nr_blocks; blk++) {
+			struct msc_block_desc *bdesc = win->block[blk].bdesc;
+
+			memset(&bdesc->hw_tag, 0, hw_sz);
+		}
+	}
+	mutex_unlock(&msc->buf_mutex);
+}
+
+/**
+ * msc_configure() - set up MSC hardware
+ * @msc:	the MSC device to configure
+ *
+ * Program storage mode, wrapping, burst length and trace buffer address
+ * into a given MSC. If msc::enabled is set, enable the trace, too.
+ */
+static int msc_configure(struct msc *msc)
+{
+	u32 reg;
+
+	if (msc->mode > MSC_MODE_MULTI)
+		return -ENOTSUPP;
+
+	if (msc->mode == MSC_MODE_MULTI)
+		msc_buffer_clear_hw_header(msc);
+
+	reg = msc->base_addr >> PAGE_SHIFT;
+	iowrite32(reg, msc->reg_base + REG_MSU_MSC0BAR);
+
+	if (msc->mode == MSC_MODE_SINGLE) {
+		reg = msc->nr_pages;
+		iowrite32(reg, msc->reg_base + REG_MSU_MSC0SIZE);
+	}
+
+	reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
+	reg &= ~(MSC_MODE | MSC_WRAPEN | MSC_EN | MSC_RD_HDR_OVRD);
+
+	reg |= msc->mode << __ffs(MSC_MODE);
+	reg |= msc->burst_len << __ffs(MSC_LEN);
+	/*if (msc->mode == MSC_MODE_MULTI)
+	  reg |= MSC_RD_HDR_OVRD; */
+	if (msc->wrap)
+		reg |= MSC_WRAPEN;
+	if (msc->enabled)
+		reg |= MSC_EN;
+
+	iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
+
+	if (msc->enabled) {
+		msc->thdev->output.multiblock = msc->mode == MSC_MODE_MULTI;
+		intel_th_trace_enable(msc->thdev);
+	}
+
+	return 0;
+}
+
+/**
+ * msc_disable() - disable MSC hardware
+ * @msc:	MSC device to disable
+ *
+ * If @msc is enabled, disable tracing on the switch and then disable MSC
+ * storage.
+ */
+static void msc_disable(struct msc *msc)
+{
+	unsigned long count;
+	u32 reg;
+
+	if (!msc->enabled)
+		return;
+
+	intel_th_trace_disable(msc->thdev);
+
+	for (reg = 0, count = MSC_PLE_WAITLOOP_DEPTH;
+	     count && !(reg & MSCSTS_PLE); count--) {
+		reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
+		cpu_relax();
+	}
+
+	if (!count)
+		dev_dbg(msc_dev(msc), "timeout waiting for MSC0 PLE\n");
+
+	if (msc->mode == MSC_MODE_SINGLE) {
+		msc->single_wrap = !!(reg & MSCSTS_WRAPSTAT);
+
+		reg = ioread32(msc->reg_base + REG_MSU_MSC0MWP);
+		msc->single_sz = reg & ((msc->nr_pages << PAGE_SHIFT) - 1);
+		dev_dbg(msc_dev(msc), "MSCnMWP: %08x/%08lx, wrap: %d\n",
+			reg, msc->single_sz, msc->single_wrap);
+	}
+
+	reg = ioread32(msc->reg_base + REG_MSU_MSC0CTL);
+	reg &= ~MSC_EN;
+	iowrite32(reg, msc->reg_base + REG_MSU_MSC0CTL);
+	msc->enabled = 0;
+
+	iowrite32(0, msc->reg_base + REG_MSU_MSC0BAR);
+	iowrite32(0, msc->reg_base + REG_MSU_MSC0SIZE);
+
+	dev_dbg(msc_dev(msc), "MSCnNWSA: %08x\n",
+		ioread32(msc->reg_base + REG_MSU_MSC0NWSA));
+
+	reg = ioread32(msc->reg_base + REG_MSU_MSC0STS);
+	dev_dbg(msc_dev(msc), "MSCnSTS: %08x\n", reg);
+}
+
+static int intel_th_msc_activate(struct intel_th_device *thdev)
+{
+	struct msc *msc = dev_get_drvdata(&thdev->dev);
+	int ret = 0;
+
+	if (!atomic_inc_unless_negative(&msc->user_count))
+		return -ENODEV;
+
+	mutex_lock(&msc->iter_mutex);
+	if (!list_empty(&msc->iter_list))
+		ret = -EBUSY;
+	mutex_unlock(&msc->iter_mutex);
+
+	if (ret) {
+		atomic_dec(&msc->user_count);
+		return ret;
+	}
+
+	msc->enabled = 1;
+
+	return msc_configure(msc);
+}
+
+static void intel_th_msc_deactivate(struct intel_th_device *thdev)
+{
+	struct msc *msc = dev_get_drvdata(&thdev->dev);
+
+	msc_disable(msc);
+
+	atomic_dec(&msc->user_count);
+}
+
+/**
+ * msc_buffer_contig_alloc() - allocate a contiguous buffer for SINGLE mode
+ * @msc:	MSC device
+ * @size:	allocation size in bytes
+ *
+ * This modifies msc::base, which requires msc::buf_mutex to serialize, so the
+ * caller is expected to hold it.
+ *
+ * Return:	0 on success, -errno otherwise.
+ */
+static int msc_buffer_contig_alloc(struct msc *msc, unsigned long size)
+{
+	unsigned int order = get_order(size);
+	struct page *page;
+
+	if (!size)
+		return 0;
+
+	page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
+	if (!page)
+		return -ENOMEM;
+
+	split_page(page, order);
+	msc->nr_pages = size >> PAGE_SHIFT;
+	msc->base = page_address(page);
+	msc->base_addr = page_to_phys(page);
+
+	return 0;
+}
+
+/**
+ * msc_buffer_contig_free() - free a contiguous buffer
+ * @msc:	MSC configured in SINGLE mode
+ */
+static void msc_buffer_contig_free(struct msc *msc)
+{
+	unsigned long off;
+
+	for (off = 0; off < msc->nr_pages << PAGE_SHIFT; off += PAGE_SIZE) {
+		struct page *page = virt_to_page(msc->base + off);
+
+		page->mapping = NULL;
+		__free_page(page);
+	}
+
+	msc->nr_pages = 0;
+}
+
+/**
+ * msc_buffer_contig_get_page() - find a page at a given offset
+ * @msc:	MSC configured in SINGLE mode
+ * @pgoff:	page offset
+ *
+ * Return:	page, if @pgoff is within the range, NULL otherwise.
+ */
+static struct page *msc_buffer_contig_get_page(struct msc *msc,
+					       unsigned long pgoff)
+{
+	if (pgoff >= msc->nr_pages)
+		return NULL;
+
+	return virt_to_page(msc->base + (pgoff << PAGE_SHIFT));
+}
+
+/**
+ * msc_buffer_win_alloc() - alloc a window for a multiblock mode
+ * @msc:	MSC device
+ * @nr_blocks:	number of pages in this window
+ *
+ * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
+ * to serialize, so the caller is expected to hold it.
+ *
+ * Return:	0 on success, -errno otherwise.
+ */
+static int msc_buffer_win_alloc(struct msc *msc, unsigned int nr_blocks)
+{
+	struct msc_window *win;
+	unsigned long size = PAGE_SIZE;
+	int i, ret = -ENOMEM;
+
+	if (!nr_blocks)
+		return 0;
+
+	win = kzalloc(offsetof(struct msc_window, block[nr_blocks]),
+		      GFP_KERNEL);
+	if (!win)
+		return -ENOMEM;
+
+	if (!list_empty(&msc->win_list)) {
+		struct msc_window *prev = list_entry(msc->win_list.prev,
+						     struct msc_window, entry);
+
+		win->pgoff = prev->pgoff + prev->nr_blocks;
+	}
+
+	for (i = 0; i < nr_blocks; i++) {
+		win->block[i].bdesc = dma_alloc_coherent(msc_dev(msc), size,
+							 &win->block[i].addr,
+							 GFP_KERNEL);
+
+#ifdef CONFIG_X86
+		/* Set the page as uncached */
+		set_memory_uc((unsigned long)win->block[i].bdesc, 1);
+#endif
+
+		if (!win->block[i].bdesc)
+			goto err_nomem;
+	}
+
+	win->msc = msc;
+	win->nr_blocks = nr_blocks;
+
+	if (list_empty(&msc->win_list)) {
+		msc->base = win->block[0].bdesc;
+		msc->base_addr = win->block[0].addr;
+	}
+
+	list_add_tail(&win->entry, &msc->win_list);
+	msc->nr_pages += nr_blocks;
+
+	return 0;
+
+err_nomem:
+	for (i--; i >= 0; i--) {
+#ifdef CONFIG_X86
+		/* Reset the page to write-back before releasing */
+		set_memory_wb((unsigned long)win->block[i].bdesc, 1);
+#endif
+		dma_free_coherent(msc_dev(msc), size, win->block[i].bdesc,
+				  win->block[i].addr);
+	}
+	kfree(win);
+
+	return ret;
+}
+
+/**
+ * msc_buffer_win_free() - free a window from MSC's window list
+ * @msc:	MSC device
+ * @win:	window to free
+ *
+ * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
+ * to serialize, so the caller is expected to hold it.
+ */
+static void msc_buffer_win_free(struct msc *msc, struct msc_window *win)
+{
+	int i;
+
+	msc->nr_pages -= win->nr_blocks;
+
+	list_del(&win->entry);
+	if (list_empty(&msc->win_list)) {
+		msc->base = NULL;
+		msc->base_addr = 0;
+	}
+
+	for (i = 0; i < win->nr_blocks; i++) {
+		struct page *page = virt_to_page(win->block[i].bdesc);
+
+		page->mapping = NULL;
+#ifdef CONFIG_X86
+		/* Reset the page to write-back before releasing */
+		set_memory_wb((unsigned long)win->block[i].bdesc, 1);
+#endif
+		dma_free_coherent(msc_dev(win->msc), PAGE_SIZE,
+				  win->block[i].bdesc, win->block[i].addr);
+	}
+
+	kfree(win);
+}
+
+/**
+ * msc_buffer_relink() - set up block descriptors for multiblock mode
+ * @msc:	MSC device
+ *
+ * This traverses msc::win_list, which requires msc::buf_mutex to serialize,
+ * so the caller is expected to hold it.
+ */
+static void msc_buffer_relink(struct msc *msc)
+{
+	struct msc_window *win, *next_win;
+
+	/* call with msc::mutex locked */
+	list_for_each_entry(win, &msc->win_list, entry) {
+		unsigned int blk;
+		u32 sw_tag = 0;
+
+		/*
+		 * Last window's next_win should point to the first window
+		 * and MSC_SW_TAG_LASTWIN should be set.
+		 */
+		if (msc_is_last_win(win)) {
+			sw_tag |= MSC_SW_TAG_LASTWIN;
+			next_win = list_entry(msc->win_list.next,
+					      struct msc_window, entry);
+		} else {
+			next_win = list_entry(win->entry.next,
+					      struct msc_window, entry);
+		}
+
+		for (blk = 0; blk < win->nr_blocks; blk++) {
+			struct msc_block_desc *bdesc = win->block[blk].bdesc;
+
+			memset(bdesc, 0, sizeof(*bdesc));
+
+			bdesc->next_win = next_win->block[0].addr >> PAGE_SHIFT;
+
+			/*
+			 * Similarly to last window, last block should point
+			 * to the first one.
+			 */
+			if (blk == win->nr_blocks - 1) {
+				sw_tag |= MSC_SW_TAG_LASTBLK;
+				bdesc->next_blk =
+					win->block[0].addr >> PAGE_SHIFT;
+			} else {
+				bdesc->next_blk =
+					win->block[blk + 1].addr >> PAGE_SHIFT;
+			}
+
+			bdesc->sw_tag = sw_tag;
+			bdesc->block_sz = PAGE_SIZE / 64;
+		}
+	}
+
+	/*
+	 * Make the above writes globally visible before tracing is
+	 * enabled to make sure hardware sees them coherently.
+	 */
+	wmb();
+}
+
+static void msc_buffer_multi_free(struct msc *msc)
+{
+	struct msc_window *win, *iter;
+
+	list_for_each_entry_safe(win, iter, &msc->win_list, entry)
+		msc_buffer_win_free(msc, win);
+}
+
+static int msc_buffer_multi_alloc(struct msc *msc, unsigned long *nr_pages,
+				  unsigned int nr_wins)
+{
+	int ret, i;
+
+	for (i = 0; i < nr_wins; i++) {
+		ret = msc_buffer_win_alloc(msc, nr_pages[i]);
+		if (ret) {
+			msc_buffer_multi_free(msc);
+			return ret;
+		}
+	}
+
+	msc_buffer_relink(msc);
+
+	return 0;
+}
+
+/**
+ * msc_buffer_free() - free buffers for MSC
+ * @msc:	MSC device
+ *
+ * Free MSC's storage buffers.
+ *
+ * This modifies msc::win_list and msc::base, which requires msc::buf_mutex to
+ * serialize, so the caller is expected to hold it.
+ */
+static void msc_buffer_free(struct msc *msc)
+{
+	if (msc->mode == MSC_MODE_SINGLE)
+		msc_buffer_contig_free(msc);
+	else if (msc->mode == MSC_MODE_MULTI)
+		msc_buffer_multi_free(msc);
+}
+
+/**
+ * msc_buffer_alloc() - allocate a buffer for MSC
+ * @msc:	MSC device
+ * @size:	allocation size in bytes
+ *
+ * Allocate a storage buffer for MSC, depending on the msc::mode, it will be
+ * either done via msc_buffer_contig_alloc() for SINGLE operation mode or
+ * msc_buffer_win_alloc() for multiblock operation. The latter allocates one
+ * window per invocation, so in multiblock mode this can be called multiple
+ * times for the same MSC to allocate multiple windows.
+ *
+ * This modifies msc::win_list and msc::base, which requires msc::buf_mutex
+ * to serialize, so the caller is expected to hold it.
+ *
+ * Return:	0 on success, -errno otherwise.
+ */
+static int msc_buffer_alloc(struct msc *msc, unsigned long *nr_pages,
+			    unsigned int nr_wins)
+{
+	int ret;
+
+	/* -1: buffer not allocated */
+	if (atomic_read(&msc->user_count) != -1)
+		return -EBUSY;
+
+	if (msc->mode == MSC_MODE_SINGLE) {
+		if (nr_wins != 1)
+			return -EINVAL;
+
+		ret = msc_buffer_contig_alloc(msc, nr_pages[0] << PAGE_SHIFT);
+	} else if (msc->mode == MSC_MODE_MULTI) {
+		ret = msc_buffer_multi_alloc(msc, nr_pages, nr_wins);
+	} else {
+		ret = -ENOTSUPP;
+	}
+
+	if (!ret) {
+		/* allocation should be visible before the counter goes to 0 */
+		smp_mb__before_atomic();
+
+		if (WARN_ON_ONCE(atomic_cmpxchg(&msc->user_count, -1, 0) != -1))
+			return -EINVAL;
+	}
+
+	return ret;
+}
+
+/**
+ * msc_buffer_unlocked_free_unless_used() - free a buffer unless it's in use
+ * @msc:	MSC device
+ *
+ * This will free MSC buffer unless it is in use or there is no allocated
+ * buffer.
+ * Caller needs to hold msc::buf_mutex.
+ *
+ * Return:	0 on successful deallocation or if there was no buffer to
+ *		deallocate, -EBUSY if there are active users.
+ */
+static int msc_buffer_unlocked_free_unless_used(struct msc *msc)
+{
+	int count, ret = 0;
+
+	count = atomic_cmpxchg(&msc->user_count, 0, -1);
+
+	/* > 0: buffer is allocated and has users */
+	if (count > 0)
+		ret = -EBUSY;
+	/* 0: buffer is allocated, no users */
+	else if (!count)
+		msc_buffer_free(msc);
+	/* < 0: no buffer, nothing to do */
+
+	return ret;
+}
+
+/**
+ * msc_buffer_free_unless_used() - free a buffer unless it's in use
+ * @msc:	MSC device
+ *
+ * This is a locked version of msc_buffer_unlocked_free_unless_used().
+ */
+static int msc_buffer_free_unless_used(struct msc *msc)
+{
+	int ret;
+
+	mutex_lock(&msc->buf_mutex);
+	ret = msc_buffer_unlocked_free_unless_used(msc);
+	mutex_unlock(&msc->buf_mutex);
+
+	return ret;
+}
+
+/**
+ * msc_buffer_get_page() - get MSC buffer page at a given offset
+ * @msc:	MSC device
+ * @pgoff:	page offset into the storage buffer
+ *
+ * This traverses msc::win_list, so holding msc::buf_mutex is expected from
+ * the caller.
+ *
+ * Return:	page if @pgoff corresponds to a valid buffer page or NULL.
+ */
+static struct page *msc_buffer_get_page(struct msc *msc, unsigned long pgoff)
+{
+	struct msc_window *win;
+
+	if (msc->mode == MSC_MODE_SINGLE)
+		return msc_buffer_contig_get_page(msc, pgoff);
+
+	list_for_each_entry(win, &msc->win_list, entry)
+		if (pgoff >= win->pgoff && pgoff < win->pgoff + win->nr_blocks)
+			goto found;
+
+	return NULL;
+
+found:
+	pgoff -= win->pgoff;
+	return virt_to_page(win->block[pgoff].bdesc);
+}
+
+/**
+ * struct msc_win_to_user_struct - data for copy_to_user() callback
+ * @buf:	userspace buffer to copy data to
+ * @offset:	running offset
+ */
+struct msc_win_to_user_struct {
+	char __user	*buf;
+	unsigned long	offset;
+};
+
+/**
+ * msc_win_to_user() - iterator for msc_buffer_iterate() to copy data to user
+ * @data:	callback's private data
+ * @src:	source buffer
+ * @len:	amount of data to copy from the source buffer
+ */
+static unsigned long msc_win_to_user(void *data, void *src, size_t len)
+{
+	struct msc_win_to_user_struct *u = data;
+	unsigned long ret;
+
+	ret = copy_to_user(u->buf + u->offset, src, len);
+	u->offset += len - ret;
+
+	return ret;
+}
+
+
+/*
+ * file operations' callbacks
+ */
+
+static int intel_th_msc_open(struct inode *inode, struct file *file)
+{
+	struct intel_th_device *thdev = file->private_data;
+	struct msc *msc = dev_get_drvdata(&thdev->dev);
+	struct msc_iter *iter;
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
+	iter = msc_iter_install(msc);
+	if (!iter)
+		return -ENOMEM;
+
+	file->private_data = iter;
+
+	return nonseekable_open(inode, file);
+}
+
+static int intel_th_msc_release(struct inode *inode, struct file *file)
+{
+	struct msc_iter *iter = file->private_data;
+	struct msc *msc = iter->msc;
+
+	msc_iter_remove(iter, msc);
+
+	return 0;
+}
+
+static ssize_t
+msc_single_to_user(struct msc *msc, char __user *buf, loff_t off, size_t len)
+{
+	unsigned long size = msc->nr_pages << PAGE_SHIFT, rem = len;
+	unsigned long start = off, tocopy = 0;
+
+	if (msc->single_wrap) {
+		start += msc->single_sz;
+		if (start < size) {
+			tocopy = min(rem, size - start);
+			if (copy_to_user(buf, msc->base + start, tocopy))
+				return -EFAULT;
+
+			buf += tocopy;
+			rem -= tocopy;
+			start += tocopy;
+		}
+
+		start &= size - 1;
+		if (rem) {
+			tocopy = min(rem, msc->single_sz - start);
+			if (copy_to_user(buf, msc->base + start, tocopy))
+				return -EFAULT;
+
+			rem -= tocopy;
+		}
+
+		return len - rem;
+	}
+
+	if (copy_to_user(buf, msc->base + start, rem))
+		return -EFAULT;
+
+	return len;
+}
+
+static ssize_t intel_th_msc_read(struct file *file, char __user *buf,
+				 size_t len, loff_t *ppos)
+{
+	struct msc_iter *iter = file->private_data;
+	struct msc *msc = iter->msc;
+	size_t size;
+	loff_t off = *ppos;
+	ssize_t ret = 0;
+
+	if (!atomic_inc_unless_negative(&msc->user_count))
+		return 0;
+
+	if (msc->enabled) {
+		ret = -EBUSY;
+		goto put_count;
+	}
+
+	if (msc->mode == MSC_MODE_SINGLE && !msc->single_wrap)
+		size = msc->single_sz;
+	else
+		size = msc->nr_pages << PAGE_SHIFT;
+
+	if (!size)
+		return 0;
+
+	if (off >= size) {
+		len = 0;
+		goto put_count;
+	}
+	if (off + len >= size)
+		len = size - off;
+
+	if (msc->mode == MSC_MODE_SINGLE) {
+		ret = msc_single_to_user(msc, buf, off, len);
+		if (ret >= 0)
+			*ppos += ret;
+	} else if (msc->mode == MSC_MODE_MULTI) {
+		struct msc_win_to_user_struct u = {
+			.buf	= buf,
+			.offset	= 0,
+		};
+
+		ret = msc_buffer_iterate(iter, len, &u, msc_win_to_user);
+		if (ret >= 0)
+			*ppos = iter->offset;
+	} else {
+		ret = -ENOTSUPP;
+	}
+
+put_count:
+	atomic_dec(&msc->user_count);
+
+	return ret;
+}
+
+/*
+ * vm operations callbacks (vm_ops)
+ */
+
+static void msc_mmap_open(struct vm_area_struct *vma)
+{
+	struct msc_iter *iter = vma->vm_file->private_data;
+	struct msc *msc = iter->msc;
+
+	atomic_inc(&msc->mmap_count);
+}
+
+static void msc_mmap_close(struct vm_area_struct *vma)
+{
+	struct msc_iter *iter = vma->vm_file->private_data;
+	struct msc *msc = iter->msc;
+	unsigned long pg;
+
+	if (!atomic_dec_and_mutex_lock(&msc->mmap_count, &msc->buf_mutex))
+		return;
+
+	/* drop page _counts */
+	for (pg = 0; pg < msc->nr_pages; pg++) {
+		struct page *page = msc_buffer_get_page(msc, pg);
+
+		if (WARN_ON_ONCE(!page))
+			continue;
+
+		if (page->mapping)
+			page->mapping = NULL;
+	}
+
+	/* last mapping -- drop user_count */
+	atomic_dec(&msc->user_count);
+	mutex_unlock(&msc->buf_mutex);
+}
+
+static int msc_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+	struct msc_iter *iter = vma->vm_file->private_data;
+	struct msc *msc = iter->msc;
+
+	vmf->page = msc_buffer_get_page(msc, vmf->pgoff);
+	if (!vmf->page)
+		return VM_FAULT_SIGBUS;
+
+	get_page(vmf->page);
+	vmf->page->mapping = vma->vm_file->f_mapping;
+	vmf->page->index = vmf->pgoff;
+
+	return 0;
+}
+
+static const struct vm_operations_struct msc_mmap_ops = {
+	.open	= msc_mmap_open,
+	.close	= msc_mmap_close,
+	.fault	= msc_mmap_fault,
+};
+
+static int intel_th_msc_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	unsigned long size = vma->vm_end - vma->vm_start;
+	struct msc_iter *iter = vma->vm_file->private_data;
+	struct msc *msc = iter->msc;
+	int ret = -EINVAL;
+
+	if (!size || offset_in_page(size))
+		return -EINVAL;
+
+	if (vma->vm_pgoff)
+		return -EINVAL;
+
+	/* grab user_count once per mmap; drop in msc_mmap_close() */
+	if (!atomic_inc_unless_negative(&msc->user_count))
+		return -EINVAL;
+
+	if (msc->mode != MSC_MODE_SINGLE &&
+	    msc->mode != MSC_MODE_MULTI)
+		goto out;
+
+	if (size >> PAGE_SHIFT != msc->nr_pages)
+		goto out;
+
+	atomic_set(&msc->mmap_count, 1);
+	ret = 0;
+
+out:
+	if (ret)
+		atomic_dec(&msc->user_count);
+
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+	vma->vm_flags |= VM_DONTEXPAND | VM_DONTCOPY;
+	vma->vm_ops = &msc_mmap_ops;
+	return ret;
+}
+
+static const struct file_operations intel_th_msc_fops = {
+	.open		= intel_th_msc_open,
+	.release	= intel_th_msc_release,
+	.read		= intel_th_msc_read,
+	.mmap		= intel_th_msc_mmap,
+	.llseek		= no_llseek,
+};
+
+static int intel_th_msc_init(struct msc *msc)
+{
+	atomic_set(&msc->user_count, -1);
+
+	msc->mode = MSC_MODE_MULTI;
+	mutex_init(&msc->buf_mutex);
+	INIT_LIST_HEAD(&msc->win_list);
+
+	mutex_init(&msc->iter_mutex);
+	INIT_LIST_HEAD(&msc->iter_list);
+
+	msc->burst_len =
+		(ioread32(msc->reg_base + REG_MSU_MSC0CTL) & MSC_LEN) >>
+		__ffs(MSC_LEN);
+
+	return 0;
+}
+
+static const char * const msc_mode[] = {
+	[MSC_MODE_SINGLE]	= "single",
+	[MSC_MODE_MULTI]	= "multi",
+	[MSC_MODE_EXI]		= "ExI",
+	[MSC_MODE_DEBUG]	= "debug",
+};
+
+static ssize_t
+wrap_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct msc *msc = dev_get_drvdata(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", msc->wrap);
+}
+
+static ssize_t
+wrap_store(struct device *dev, struct device_attribute *attr, const char *buf,
+	   size_t size)
+{
+	struct msc *msc = dev_get_drvdata(dev);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	msc->wrap = !!val;
+
+	return size;
+}
+
+static DEVICE_ATTR_RW(wrap);
+
+static ssize_t
+mode_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct msc *msc = dev_get_drvdata(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%s\n", msc_mode[msc->mode]);
+}
+
+static ssize_t
+mode_store(struct device *dev, struct device_attribute *attr, const char *buf,
+	   size_t size)
+{
+	struct msc *msc = dev_get_drvdata(dev);
+	size_t len = size;
+	char *cp;
+	int i, ret;
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
+	cp = memchr(buf, '\n', len);
+	if (cp)
+		len = cp - buf;
+
+	for (i = 0; i < ARRAY_SIZE(msc_mode); i++)
+		if (!strncmp(msc_mode[i], buf, len))
+			goto found;
+
+	return -EINVAL;
+
+found:
+	mutex_lock(&msc->buf_mutex);
+	ret = msc_buffer_unlocked_free_unless_used(msc);
+	if (!ret)
+		msc->mode = i;
+	mutex_unlock(&msc->buf_mutex);
+
+	return ret ? ret : size;
+}
+
+static DEVICE_ATTR_RW(mode);
+
+static ssize_t
+nr_pages_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct msc *msc = dev_get_drvdata(dev);
+	struct msc_window *win;
+	size_t count = 0;
+
+	mutex_lock(&msc->buf_mutex);
+
+	if (msc->mode == MSC_MODE_SINGLE)
+		count = scnprintf(buf, PAGE_SIZE, "%ld\n", msc->nr_pages);
+	else if (msc->mode == MSC_MODE_MULTI) {
+		list_for_each_entry(win, &msc->win_list, entry) {
+			count += scnprintf(buf + count, PAGE_SIZE - count,
+					   "%d%c", win->nr_blocks,
+					   msc_is_last_win(win) ? '\n' : ',');
+		}
+	} else {
+		count = scnprintf(buf, PAGE_SIZE, "unsupported\n");
+	}
+
+	mutex_unlock(&msc->buf_mutex);
+
+	return count;
+}
+
+static ssize_t
+nr_pages_store(struct device *dev, struct device_attribute *attr,
+	       const char *buf, size_t size)
+{
+	struct msc *msc = dev_get_drvdata(dev);
+	unsigned long val, *win = NULL, *rewin;
+	size_t len = size;
+	const char *p = buf;
+	char *end, *s;
+	int ret, nr_wins = 0;
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
+	ret = msc_buffer_free_unless_used(msc);
+	if (ret)
+		return ret;
+
+	/* scan the comma-separated list of allocation sizes */
+	end = memchr(buf, '\n', len);
+	if (end)
+		len = end - buf;
+
+	do {
+		end = memchr(p, ',', len);
+		s = kstrndup(p, end ? end - p : len, GFP_KERNEL);
+		ret = kstrtoul(s, 10, &val);
+		kfree(s);
+
+		if (ret || !val)
+			goto free_win;
+
+		if (nr_wins && msc->mode == MSC_MODE_SINGLE) {
+			ret = -EINVAL;
+			goto free_win;
+		}
+
+		nr_wins++;
+		rewin = krealloc(win, sizeof(*win) * nr_wins, GFP_KERNEL);
+		if (!rewin) {
+			kfree(win);
+			return -ENOMEM;
+		}
+
+		win = rewin;
+		win[nr_wins - 1] = val;
+
+		if (!end)
+			break;
+
+		len -= end - p;
+		p = end + 1;
+	} while (len);
+
+	mutex_lock(&msc->buf_mutex);
+	ret = msc_buffer_alloc(msc, win, nr_wins);
+	mutex_unlock(&msc->buf_mutex);
+
+free_win:
+	kfree(win);
+
+	return ret ? ret : size;
+}
+
+static DEVICE_ATTR_RW(nr_pages);
+
+static struct attribute *msc_output_attrs[] = {
+	&dev_attr_wrap.attr,
+	&dev_attr_mode.attr,
+	&dev_attr_nr_pages.attr,
+	NULL,
+};
+
+static struct attribute_group msc_output_group = {
+	.attrs	= msc_output_attrs,
+};
+
+static int intel_th_msc_probe(struct intel_th_device *thdev)
+{
+	struct device *dev = &thdev->dev;
+	struct resource *res;
+	struct msc *msc;
+	void __iomem *base;
+	int err;
+
+	res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	base = devm_ioremap(dev, res->start, resource_size(res));
+	if (!base)
+		return -ENOMEM;
+
+	msc = devm_kzalloc(dev, sizeof(*msc), GFP_KERNEL);
+	if (!msc)
+		return -ENOMEM;
+
+	msc->index = thdev->id;
+
+	msc->thdev = thdev;
+	msc->reg_base = base + msc->index * 0x100;
+
+	err = intel_th_msc_init(msc);
+	if (err)
+		return err;
+
+	err = sysfs_create_group(&dev->kobj, &msc_output_group);
+	if (err)
+		return err;
+
+	dev_set_drvdata(dev, msc);
+
+	return 0;
+}
+
+static void intel_th_msc_remove(struct intel_th_device *thdev)
+{
+	sysfs_remove_group(&thdev->dev.kobj, &msc_output_group);
+}
+
+static struct intel_th_driver intel_th_msc_driver = {
+	.probe	= intel_th_msc_probe,
+	.remove	= intel_th_msc_remove,
+	.activate	= intel_th_msc_activate,
+	.deactivate	= intel_th_msc_deactivate,
+	.fops	= &intel_th_msc_fops,
+	.driver	= {
+		.name	= "msc",
+		.owner	= THIS_MODULE,
+	},
+};
+
+module_driver(intel_th_msc_driver,
+	      intel_th_driver_register,
+	      intel_th_driver_unregister);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel(R) Trace Hub Memory Storage Unit driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
diff --git a/drivers/hwtracing/intel_th/msu.h b/drivers/hwtracing/intel_th/msu.h
new file mode 100644
index 000000000000..9b710e4aa98a
--- /dev/null
+++ b/drivers/hwtracing/intel_th/msu.h
@@ -0,0 +1,116 @@
+/*
+ * Intel(R) Trace Hub Memory Storage Unit (MSU) data structures
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#ifndef __INTEL_TH_MSU_H__
+#define __INTEL_TH_MSU_H__
+
+enum {
+	REG_MSU_MSUPARAMS	= 0x0000,
+	REG_MSU_MSUSTS		= 0x0008,
+	REG_MSU_MSC0CTL		= 0x0100, /* MSC0 control */
+	REG_MSU_MSC0STS		= 0x0104, /* MSC0 status */
+	REG_MSU_MSC0BAR		= 0x0108, /* MSC0 output base address */
+	REG_MSU_MSC0SIZE	= 0x010c, /* MSC0 output size */
+	REG_MSU_MSC0MWP		= 0x0110, /* MSC0 write pointer */
+	REG_MSU_MSC0NWSA	= 0x011c, /* MSC0 next window start address */
+
+	REG_MSU_MSC1CTL		= 0x0200, /* MSC1 control */
+	REG_MSU_MSC1STS		= 0x0204, /* MSC1 status */
+	REG_MSU_MSC1BAR		= 0x0208, /* MSC1 output base address */
+	REG_MSU_MSC1SIZE	= 0x020c, /* MSC1 output size */
+	REG_MSU_MSC1MWP		= 0x0210, /* MSC1 write pointer */
+	REG_MSU_MSC1NWSA	= 0x021c, /* MSC1 next window start address */
+};
+
+/* MSUSTS bits */
+#define MSUSTS_MSU_INT	BIT(0)
+
+/* MSCnCTL bits */
+#define MSC_EN		BIT(0)
+#define MSC_WRAPEN	BIT(1)
+#define MSC_RD_HDR_OVRD	BIT(2)
+#define MSC_MODE	(BIT(4) | BIT(5))
+#define MSC_LEN		(BIT(8) | BIT(9) | BIT(10))
+
+/* MSC operating modes (MSC_MODE) */
+enum {
+	MSC_MODE_SINGLE	= 0,
+	MSC_MODE_MULTI,
+	MSC_MODE_EXI,
+	MSC_MODE_DEBUG,
+};
+
+/* MSCnSTS bits */
+#define MSCSTS_WRAPSTAT	BIT(1)	/* Wrap occurred */
+#define MSCSTS_PLE	BIT(2)	/* Pipeline Empty */
+
+/*
+ * Multiblock/multiwindow block descriptor
+ */
+struct msc_block_desc {
+	u32	sw_tag;
+	u32	block_sz;
+	u32	next_blk;
+	u32	next_win;
+	u32	res0[4];
+	u32	hw_tag;
+	u32	valid_dw;
+	u32	ts_low;
+	u32	ts_high;
+	u32	res1[4];
+} __packed;
+
+#define MSC_BDESC	sizeof(struct msc_block_desc)
+#define DATA_IN_PAGE	(PAGE_SIZE - MSC_BDESC)
+
+/* MSC multiblock sw tag bits */
+#define MSC_SW_TAG_LASTBLK	BIT(0)
+#define MSC_SW_TAG_LASTWIN	BIT(1)
+
+/* MSC multiblock hw tag bits */
+#define MSC_HW_TAG_TRIGGER	BIT(0)
+#define MSC_HW_TAG_BLOCKWRAP	BIT(1)
+#define MSC_HW_TAG_WINWRAP	BIT(2)
+#define MSC_HW_TAG_ENDBIT	BIT(3)
+
+static inline unsigned long msc_data_sz(struct msc_block_desc *bdesc)
+{
+	if (!bdesc->valid_dw)
+		return 0;
+
+	return bdesc->valid_dw * 4 - MSC_BDESC;
+}
+
+static inline bool msc_block_wrapped(struct msc_block_desc *bdesc)
+{
+	if (bdesc->hw_tag & MSC_HW_TAG_BLOCKWRAP)
+		return true;
+
+	return false;
+}
+
+static inline bool msc_block_last_written(struct msc_block_desc *bdesc)
+{
+	if ((bdesc->hw_tag & MSC_HW_TAG_ENDBIT) ||
+	    (msc_data_sz(bdesc) != DATA_IN_PAGE))
+		return true;
+
+	return false;
+}
+
+/* waiting for Pipeline Empty bit(s) to assert for MSC */
+#define MSC_PLE_WAITLOOP_DEPTH	10000
+
+#endif /* __INTEL_TH_MSU_H__ */
diff --git a/drivers/hwtracing/intel_th/pci.c b/drivers/hwtracing/intel_th/pci.c
new file mode 100644
index 000000000000..641e87936064
--- /dev/null
+++ b/drivers/hwtracing/intel_th/pci.c
@@ -0,0 +1,86 @@
+/*
+ * Intel(R) Trace Hub pci driver
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/sysfs.h>
+#include <linux/pci.h>
+
+#include "intel_th.h"
+
+#define DRIVER_NAME "intel_th_pci"
+
+#define BAR_MASK (BIT(TH_MMIO_CONFIG) | BIT(TH_MMIO_SW))
+
+static int intel_th_pci_probe(struct pci_dev *pdev,
+			      const struct pci_device_id *id)
+{
+	struct intel_th *th;
+	int err;
+
+	err = pcim_enable_device(pdev);
+	if (err)
+		return err;
+
+	err = pcim_iomap_regions_request_all(pdev, BAR_MASK, DRIVER_NAME);
+	if (err)
+		return err;
+
+	th = intel_th_alloc(&pdev->dev, pdev->resource,
+			    DEVICE_COUNT_RESOURCE, pdev->irq);
+	if (IS_ERR(th))
+		return PTR_ERR(th);
+
+	pci_set_drvdata(pdev, th);
+
+	return 0;
+}
+
+static void intel_th_pci_remove(struct pci_dev *pdev)
+{
+	struct intel_th *th = pci_get_drvdata(pdev);
+
+	intel_th_free(th);
+}
+
+static const struct pci_device_id intel_th_pci_id_table[] = {
+	{
+		PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x9d26),
+		.driver_data = (kernel_ulong_t)0,
+	},
+	{
+		PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0xa126),
+		.driver_data = (kernel_ulong_t)0,
+	},
+	{ 0 },
+};
+
+MODULE_DEVICE_TABLE(pci, intel_th_pci_id_table);
+
+static struct pci_driver intel_th_pci_driver = {
+	.name		= DRIVER_NAME,
+	.id_table	= intel_th_pci_id_table,
+	.probe		= intel_th_pci_probe,
+	.remove		= intel_th_pci_remove,
+};
+
+module_pci_driver(intel_th_pci_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel(R) Trace Hub PCI controller driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@intel.com>");
diff --git a/drivers/hwtracing/intel_th/pti.c b/drivers/hwtracing/intel_th/pti.c
new file mode 100644
index 000000000000..57cbfdcc7ef0
--- /dev/null
+++ b/drivers/hwtracing/intel_th/pti.c
@@ -0,0 +1,252 @@
+/*
+ * Intel(R) Trace Hub PTI output driver
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/sizes.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/io.h>
+
+#include "intel_th.h"
+#include "pti.h"
+
+struct pti_device {
+	void __iomem		*base;
+	struct intel_th_device	*thdev;
+	unsigned int		mode;
+	unsigned int		freeclk;
+	unsigned int		clkdiv;
+	unsigned int		patgen;
+};
+
+/* map PTI widths to MODE settings of PTI_CTL register */
+static const unsigned int pti_mode[] = {
+	0, 4, 8, 0, 12, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 0,
+};
+
+static int pti_width_mode(unsigned int width)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(pti_mode); i++)
+		if (pti_mode[i] == width)
+			return i;
+
+	return -EINVAL;
+}
+
+static ssize_t mode_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct pti_device *pti = dev_get_drvdata(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", pti_mode[pti->mode]);
+}
+
+static ssize_t mode_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t size)
+{
+	struct pti_device *pti = dev_get_drvdata(dev);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	ret = pti_width_mode(val);
+	if (ret < 0)
+		return ret;
+
+	pti->mode = ret;
+
+	return size;
+}
+
+static DEVICE_ATTR_RW(mode);
+
+static ssize_t
+freerunning_clock_show(struct device *dev, struct device_attribute *attr,
+		       char *buf)
+{
+	struct pti_device *pti = dev_get_drvdata(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", pti->freeclk);
+}
+
+static ssize_t
+freerunning_clock_store(struct device *dev, struct device_attribute *attr,
+			const char *buf, size_t size)
+{
+	struct pti_device *pti = dev_get_drvdata(dev);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	pti->freeclk = !!val;
+
+	return size;
+}
+
+static DEVICE_ATTR_RW(freerunning_clock);
+
+static ssize_t
+clock_divider_show(struct device *dev, struct device_attribute *attr,
+		   char *buf)
+{
+	struct pti_device *pti = dev_get_drvdata(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%d\n", 1u << pti->clkdiv);
+}
+
+static ssize_t
+clock_divider_store(struct device *dev, struct device_attribute *attr,
+		    const char *buf, size_t size)
+{
+	struct pti_device *pti = dev_get_drvdata(dev);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	if (!is_power_of_2(val) || val > 8 || !val)
+		return -EINVAL;
+
+	pti->clkdiv = val;
+
+	return size;
+}
+
+static DEVICE_ATTR_RW(clock_divider);
+
+static struct attribute *pti_output_attrs[] = {
+	&dev_attr_mode.attr,
+	&dev_attr_freerunning_clock.attr,
+	&dev_attr_clock_divider.attr,
+	NULL,
+};
+
+static struct attribute_group pti_output_group = {
+	.attrs	= pti_output_attrs,
+};
+
+static int intel_th_pti_activate(struct intel_th_device *thdev)
+{
+	struct pti_device *pti = dev_get_drvdata(&thdev->dev);
+	u32 ctl = PTI_EN;
+
+	if (pti->patgen)
+		ctl |= pti->patgen << __ffs(PTI_PATGENMODE);
+	if (pti->freeclk)
+		ctl |= PTI_FCEN;
+	ctl |= pti->mode << __ffs(PTI_MODE);
+	ctl |= pti->clkdiv << __ffs(PTI_CLKDIV);
+
+	iowrite32(ctl, pti->base + REG_PTI_CTL);
+
+	intel_th_trace_enable(thdev);
+
+	return 0;
+}
+
+static void intel_th_pti_deactivate(struct intel_th_device *thdev)
+{
+	struct pti_device *pti = dev_get_drvdata(&thdev->dev);
+
+	intel_th_trace_disable(thdev);
+
+	iowrite32(0, pti->base + REG_PTI_CTL);
+}
+
+static void read_hw_config(struct pti_device *pti)
+{
+	u32 ctl = ioread32(pti->base + REG_PTI_CTL);
+
+	pti->mode	= (ctl & PTI_MODE) >> __ffs(PTI_MODE);
+	pti->clkdiv	= (ctl & PTI_CLKDIV) >> __ffs(PTI_CLKDIV);
+	pti->freeclk	= !!(ctl & PTI_FCEN);
+
+	if (!pti_mode[pti->mode])
+		pti->mode = pti_width_mode(4);
+	if (!pti->clkdiv)
+		pti->clkdiv = 1;
+}
+
+static int intel_th_pti_probe(struct intel_th_device *thdev)
+{
+	struct device *dev = &thdev->dev;
+	struct resource *res;
+	struct pti_device *pti;
+	void __iomem *base;
+	int ret;
+
+	res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	base = devm_ioremap(dev, res->start, resource_size(res));
+	if (!base)
+		return -ENOMEM;
+
+	pti = devm_kzalloc(dev, sizeof(*pti), GFP_KERNEL);
+	if (!pti)
+		return -ENOMEM;
+
+	pti->thdev = thdev;
+	pti->base = base;
+
+	read_hw_config(pti);
+
+	ret = sysfs_create_group(&dev->kobj, &pti_output_group);
+	if (ret)
+		return ret;
+
+	dev_set_drvdata(dev, pti);
+
+	return 0;
+}
+
+static void intel_th_pti_remove(struct intel_th_device *thdev)
+{
+}
+
+static struct intel_th_driver intel_th_pti_driver = {
+	.probe	= intel_th_pti_probe,
+	.remove	= intel_th_pti_remove,
+	.activate	= intel_th_pti_activate,
+	.deactivate	= intel_th_pti_deactivate,
+	.driver	= {
+		.name	= "pti",
+		.owner	= THIS_MODULE,
+	},
+};
+
+module_driver(intel_th_pti_driver,
+	      intel_th_driver_register,
+	      intel_th_driver_unregister);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel(R) Trace Hub PTI output driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
diff --git a/drivers/hwtracing/intel_th/pti.h b/drivers/hwtracing/intel_th/pti.h
new file mode 100644
index 000000000000..20883f5628cf
--- /dev/null
+++ b/drivers/hwtracing/intel_th/pti.h
@@ -0,0 +1,29 @@
+/*
+ * Intel(R) Trace Hub PTI output data structures
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#ifndef __INTEL_TH_STH_H__
+#define __INTEL_TH_STH_H__
+
+enum {
+	REG_PTI_CTL	= 0x1c00,
+};
+
+#define PTI_EN		BIT(0)
+#define PTI_FCEN	BIT(1)
+#define PTI_MODE	0xf0
+#define PTI_CLKDIV	0x000f0000
+#define PTI_PATGENMODE	0x00f00000
+
+#endif /* __INTEL_TH_STH_H__ */
diff --git a/drivers/hwtracing/intel_th/sth.c b/drivers/hwtracing/intel_th/sth.c
new file mode 100644
index 000000000000..56101c33e10f
--- /dev/null
+++ b/drivers/hwtracing/intel_th/sth.c
@@ -0,0 +1,259 @@
+/*
+ * Intel(R) Trace Hub Software Trace Hub support
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/stm.h>
+
+#include "intel_th.h"
+#include "sth.h"
+
+struct sth_device {
+	void __iomem	*base;
+	void __iomem	*channels;
+	phys_addr_t	channels_phys;
+	struct device	*dev;
+	struct stm_data	stm;
+	unsigned int	sw_nmasters;
+};
+
+static struct intel_th_channel __iomem *
+sth_channel(struct sth_device *sth, unsigned int master, unsigned int channel)
+{
+	struct intel_th_channel __iomem *sw_map = sth->channels;
+
+	return &sw_map[(master - sth->stm.sw_start) * sth->stm.sw_nchannels +
+		       channel];
+}
+
+static void sth_iowrite(void __iomem *dest, const unsigned char *payload,
+			unsigned int size)
+{
+	switch (size) {
+#ifdef CONFIG_64BIT
+	case 8:
+		writeq_relaxed(*(u64 *)payload, dest);
+		break;
+#endif
+	case 4:
+		writel_relaxed(*(u32 *)payload, dest);
+		break;
+	case 2:
+		writew_relaxed(*(u16 *)payload, dest);
+		break;
+	case 1:
+		writeb_relaxed(*(u8 *)payload, dest);
+		break;
+	default:
+		break;
+	}
+}
+
+static ssize_t sth_stm_packet(struct stm_data *stm_data, unsigned int master,
+			      unsigned int channel, unsigned int packet,
+			      unsigned int flags, unsigned int size,
+			      const unsigned char *payload)
+{
+	struct sth_device *sth = container_of(stm_data, struct sth_device, stm);
+	struct intel_th_channel __iomem *out =
+		sth_channel(sth, master, channel);
+	u64 __iomem *outp = &out->Dn;
+	unsigned long reg = REG_STH_TRIG;
+
+#ifndef CONFIG_64BIT
+	if (size > 4)
+		size = 4;
+#endif
+
+	size = rounddown_pow_of_two(size);
+
+	switch (packet) {
+	/* Global packets (GERR, XSYNC, TRIG) are sent with register writes */
+	case STP_PACKET_GERR:
+		reg += 4;
+	case STP_PACKET_XSYNC:
+		reg += 8;
+	case STP_PACKET_TRIG:
+		if (flags & STP_PACKET_TIMESTAMPED)
+			reg += 4;
+		iowrite8(*payload, sth->base + reg);
+		break;
+
+	case STP_PACKET_MERR:
+		sth_iowrite(&out->MERR, payload, size);
+		break;
+
+	case STP_PACKET_FLAG:
+		if (flags & STP_PACKET_TIMESTAMPED)
+			outp = (u64 __iomem *)&out->FLAG_TS;
+		else
+			outp = (u64 __iomem *)&out->FLAG;
+
+		size = 1;
+		sth_iowrite(outp, payload, size);
+		break;
+
+	case STP_PACKET_USER:
+		if (flags & STP_PACKET_TIMESTAMPED)
+			outp = &out->USER_TS;
+		else
+			outp = &out->USER;
+		sth_iowrite(outp, payload, size);
+		break;
+
+	case STP_PACKET_DATA:
+		outp = &out->Dn;
+
+		if (flags & STP_PACKET_TIMESTAMPED)
+			outp += 2;
+		if (flags & STP_PACKET_MARKED)
+			outp++;
+
+		sth_iowrite(outp, payload, size);
+		break;
+	}
+
+	return size;
+}
+
+static phys_addr_t
+sth_stm_mmio_addr(struct stm_data *stm_data, unsigned int master,
+		  unsigned int channel, unsigned int nr_chans)
+{
+	struct sth_device *sth = container_of(stm_data, struct sth_device, stm);
+	phys_addr_t addr;
+
+	master -= sth->stm.sw_start;
+	addr = sth->channels_phys + (master * sth->stm.sw_nchannels + channel) *
+		sizeof(struct intel_th_channel);
+
+	if (offset_in_page(addr) ||
+	    offset_in_page(nr_chans * sizeof(struct intel_th_channel)))
+		return 0;
+
+	return addr;
+}
+
+static int sth_stm_link(struct stm_data *stm_data, unsigned int master,
+			 unsigned int channel)
+{
+	struct sth_device *sth = container_of(stm_data, struct sth_device, stm);
+
+	intel_th_set_output(to_intel_th_device(sth->dev), master);
+
+	return 0;
+}
+
+static int intel_th_sw_init(struct sth_device *sth)
+{
+	u32 reg;
+
+	reg = ioread32(sth->base + REG_STH_STHCAP1);
+	sth->stm.sw_nchannels = reg & 0xff;
+
+	reg = ioread32(sth->base + REG_STH_STHCAP0);
+	sth->stm.sw_start = reg & 0xffff;
+	sth->stm.sw_end = reg >> 16;
+
+	sth->sw_nmasters = sth->stm.sw_end - sth->stm.sw_start;
+	dev_dbg(sth->dev, "sw_start: %x sw_end: %x masters: %x nchannels: %x\n",
+		sth->stm.sw_start, sth->stm.sw_end, sth->sw_nmasters,
+		sth->stm.sw_nchannels);
+
+	return 0;
+}
+
+static int intel_th_sth_probe(struct intel_th_device *thdev)
+{
+	struct device *dev = &thdev->dev;
+	struct sth_device *sth;
+	struct resource *res;
+	void __iomem *base, *channels;
+	int err;
+
+	res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	base = devm_ioremap(dev, res->start, resource_size(res));
+	if (!base)
+		return -ENOMEM;
+
+	res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 1);
+	if (!res)
+		return -ENODEV;
+
+	channels = devm_ioremap(dev, res->start, resource_size(res));
+	if (!channels)
+		return -ENOMEM;
+
+	sth = devm_kzalloc(dev, sizeof(*sth), GFP_KERNEL);
+	if (!sth)
+		return -ENOMEM;
+
+	sth->dev = dev;
+	sth->base = base;
+	sth->channels = channels;
+	sth->channels_phys = res->start;
+	sth->stm.name = dev_name(dev);
+	sth->stm.packet = sth_stm_packet;
+	sth->stm.mmio_addr = sth_stm_mmio_addr;
+	sth->stm.sw_mmiosz = sizeof(struct intel_th_channel);
+	sth->stm.link = sth_stm_link;
+
+	err = intel_th_sw_init(sth);
+	if (err)
+		return err;
+
+	err = stm_register_device(dev, &sth->stm, THIS_MODULE);
+	if (err) {
+		dev_err(dev, "stm_register_device failed\n");
+		return err;
+	}
+
+	dev_set_drvdata(dev, sth);
+
+	return 0;
+}
+
+static void intel_th_sth_remove(struct intel_th_device *thdev)
+{
+	struct sth_device *sth = dev_get_drvdata(&thdev->dev);
+
+	stm_unregister_device(&sth->stm);
+}
+
+static struct intel_th_driver intel_th_sth_driver = {
+	.probe	= intel_th_sth_probe,
+	.remove	= intel_th_sth_remove,
+	.driver	= {
+		.name	= "sth",
+		.owner	= THIS_MODULE,
+	},
+};
+
+module_driver(intel_th_sth_driver,
+	      intel_th_driver_register,
+	      intel_th_driver_unregister);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel(R) Trace Hub Software Trace Hub driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@intel.com>");
diff --git a/drivers/hwtracing/intel_th/sth.h b/drivers/hwtracing/intel_th/sth.h
new file mode 100644
index 000000000000..f1390cd4f2ed
--- /dev/null
+++ b/drivers/hwtracing/intel_th/sth.h
@@ -0,0 +1,42 @@
+/*
+ * Intel(R) Trace Hub Software Trace Hub (STH) data structures
+ *
+ * Copyright (C) 2014-2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ */
+
+#ifndef __INTEL_TH_STH_H__
+#define __INTEL_TH_STH_H__
+
+enum {
+	REG_STH_STHCAP0		= 0x0000, /* capabilities pt1 */
+	REG_STH_STHCAP1		= 0x0004, /* capabilities pt2 */
+	REG_STH_TRIG		= 0x0008, /* TRIG packet payload */
+	REG_STH_TRIG_TS		= 0x000c, /* TRIG_TS packet payload */
+	REG_STH_XSYNC		= 0x0010, /* XSYNC packet payload */
+	REG_STH_XSYNC_TS	= 0x0014, /* XSYNC_TS packet payload */
+	REG_STH_GERR		= 0x0018, /* GERR packet payload */
+};
+
+struct intel_th_channel {
+	u64	Dn;
+	u64	DnM;
+	u64	DnTS;
+	u64	DnMTS;
+	u64	USER;
+	u64	USER_TS;
+	u32	FLAG;
+	u32	FLAG_TS;
+	u32	MERR;
+	u32	__unused;
+} __packed;
+
+#endif /* __INTEL_TH_STH_H__ */
diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig
new file mode 100644
index 000000000000..83e9f591a54b
--- /dev/null
+++ b/drivers/hwtracing/stm/Kconfig
@@ -0,0 +1,26 @@
+config STM
+	tristate "System Trace Module devices"
+	select CONFIGFS_FS
+	help
+	  A System Trace Module (STM) is a device exporting data in System
+	  Trace Protocol (STP) format as defined by MIPI STP standards.
+	  Examples of such devices are Intel(R) Trace Hub and Coresight STM.
+
+	  Say Y here to enable System Trace Module device support.
+
+config STM_DUMMY
+	tristate "Dummy STM driver"
+	help
+	  This is a simple dummy device that pretends to be an stm device
+	  and discards your data. Use for stm class testing.
+
+	  If you don't know what this is, say N.
+
+config STM_SOURCE_CONSOLE
+	tristate "Kernel console over STM devices"
+	help
+	  This is a kernel space trace source that sends kernel log
+	  messages to trace hosts over STM devices.
+
+	  If you want to send kernel console messages over STM devices,
+	  say Y.
diff --git a/drivers/hwtracing/stm/Makefile b/drivers/hwtracing/stm/Makefile
new file mode 100644
index 000000000000..f9312c38dd7a
--- /dev/null
+++ b/drivers/hwtracing/stm/Makefile
@@ -0,0 +1,9 @@
+obj-$(CONFIG_STM)	+= stm_core.o
+
+stm_core-y		:= core.o policy.o
+
+obj-$(CONFIG_STM_DUMMY)	+= dummy_stm.o
+
+obj-$(CONFIG_STM_SOURCE_CONSOLE)	+= stm_console.o
+
+stm_console-y		:= console.o
diff --git a/drivers/hwtracing/stm/console.c b/drivers/hwtracing/stm/console.c
new file mode 100644
index 000000000000..c9d9a8d2ff52
--- /dev/null
+++ b/drivers/hwtracing/stm/console.c
@@ -0,0 +1,80 @@
+/*
+ * Simple kernel console driver for STM devices
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * STM console will send kernel messages over STM devices to a trace host.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/console.h>
+#include <linux/slab.h>
+#include <linux/stm.h>
+
+static int stm_console_link(struct stm_source_data *data);
+static void stm_console_unlink(struct stm_source_data *data);
+
+static struct stm_console {
+	struct stm_source_data	data;
+	struct console		console;
+} stm_console = {
+	.data	= {
+		.name		= "console",
+		.nr_chans	= 1,
+		.link		= stm_console_link,
+		.unlink		= stm_console_unlink,
+	},
+};
+
+static void
+stm_console_write(struct console *con, const char *buf, unsigned len)
+{
+	struct stm_console *sc = container_of(con, struct stm_console, console);
+
+	stm_source_write(&sc->data, 0, buf, len);
+}
+
+static int stm_console_link(struct stm_source_data *data)
+{
+	struct stm_console *sc = container_of(data, struct stm_console, data);
+
+	strcpy(sc->console.name, "stm_console");
+	sc->console.write = stm_console_write;
+	sc->console.flags = CON_ENABLED | CON_PRINTBUFFER;
+	register_console(&sc->console);
+
+	return 0;
+}
+
+static void stm_console_unlink(struct stm_source_data *data)
+{
+	struct stm_console *sc = container_of(data, struct stm_console, data);
+
+	unregister_console(&sc->console);
+}
+
+static int stm_console_init(void)
+{
+	return stm_source_register_device(NULL, &stm_console.data);
+}
+
+static void stm_console_exit(void)
+{
+	stm_source_unregister_device(&stm_console.data);
+}
+
+module_init(stm_console_init);
+module_exit(stm_console_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("stm_console driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c
new file mode 100644
index 000000000000..b6445d9e5453
--- /dev/null
+++ b/drivers/hwtracing/stm/core.c
@@ -0,0 +1,1032 @@
+/*
+ * System Trace Module (STM) infrastructure
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * STM class implements generic infrastructure for  System Trace Module devices
+ * as defined in MIPI STPv2 specification.
+ */
+
+#include <linux/uaccess.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/compat.h>
+#include <linux/kdev_t.h>
+#include <linux/srcu.h>
+#include <linux/slab.h>
+#include <linux/stm.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include "stm.h"
+
+#include <uapi/linux/stm.h>
+
+static unsigned int stm_core_up;
+
+/*
+ * The SRCU here makes sure that STM device doesn't disappear from under a
+ * stm_source_write() caller, which may want to have as little overhead as
+ * possible.
+ */
+static struct srcu_struct stm_source_srcu;
+
+static ssize_t masters_show(struct device *dev,
+			    struct device_attribute *attr,
+			    char *buf)
+{
+	struct stm_device *stm = to_stm_device(dev);
+	int ret;
+
+	ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end);
+
+	return ret;
+}
+
+static DEVICE_ATTR_RO(masters);
+
+static ssize_t channels_show(struct device *dev,
+			     struct device_attribute *attr,
+			     char *buf)
+{
+	struct stm_device *stm = to_stm_device(dev);
+	int ret;
+
+	ret = sprintf(buf, "%u\n", stm->data->sw_nchannels);
+
+	return ret;
+}
+
+static DEVICE_ATTR_RO(channels);
+
+static struct attribute *stm_attrs[] = {
+	&dev_attr_masters.attr,
+	&dev_attr_channels.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(stm);
+
+static struct class stm_class = {
+	.name		= "stm",
+	.dev_groups	= stm_groups,
+};
+
+static int stm_dev_match(struct device *dev, const void *data)
+{
+	const char *name = data;
+
+	return sysfs_streq(name, dev_name(dev));
+}
+
+/**
+ * stm_find_device() - find stm device by name
+ * @buf:	character buffer containing the name
+ *
+ * This is called when either policy gets assigned to an stm device or an
+ * stm_source device gets linked to an stm device.
+ *
+ * This grabs device's reference (get_device()) and module reference, both
+ * of which the calling path needs to make sure to drop with stm_put_device().
+ *
+ * Return:	stm device pointer or null if lookup failed.
+ */
+struct stm_device *stm_find_device(const char *buf)
+{
+	struct stm_device *stm;
+	struct device *dev;
+
+	if (!stm_core_up)
+		return NULL;
+
+	dev = class_find_device(&stm_class, NULL, buf, stm_dev_match);
+	if (!dev)
+		return NULL;
+
+	stm = to_stm_device(dev);
+	if (!try_module_get(stm->owner)) {
+		put_device(dev);
+		return NULL;
+	}
+
+	return stm;
+}
+
+/**
+ * stm_put_device() - drop references on the stm device
+ * @stm:	stm device, previously acquired by stm_find_device()
+ *
+ * This drops the module reference and device reference taken by
+ * stm_find_device().
+ */
+void stm_put_device(struct stm_device *stm)
+{
+	module_put(stm->owner);
+	put_device(&stm->dev);
+}
+
+/*
+ * Internally we only care about software-writable masters here, that is the
+ * ones in the range [stm_data->sw_start..stm_data..sw_end], however we need
+ * original master numbers to be visible externally, since they are the ones
+ * that will appear in the STP stream. Thus, the internal bookkeeping uses
+ * $master - stm_data->sw_start to reference master descriptors and such.
+ */
+
+#define __stm_master(_s, _m)				\
+	((_s)->masters[(_m) - (_s)->data->sw_start])
+
+static inline struct stp_master *
+stm_master(struct stm_device *stm, unsigned int idx)
+{
+	if (idx < stm->data->sw_start || idx > stm->data->sw_end)
+		return NULL;
+
+	return __stm_master(stm, idx);
+}
+
+static int stp_master_alloc(struct stm_device *stm, unsigned int idx)
+{
+	struct stp_master *master;
+	size_t size;
+
+	size = ALIGN(stm->data->sw_nchannels, 8) / 8;
+	size += sizeof(struct stp_master);
+	master = kzalloc(size, GFP_ATOMIC);
+	if (!master)
+		return -ENOMEM;
+
+	master->nr_free = stm->data->sw_nchannels;
+	__stm_master(stm, idx) = master;
+
+	return 0;
+}
+
+static void stp_master_free(struct stm_device *stm, unsigned int idx)
+{
+	struct stp_master *master = stm_master(stm, idx);
+
+	if (!master)
+		return;
+
+	__stm_master(stm, idx) = NULL;
+	kfree(master);
+}
+
+static void stm_output_claim(struct stm_device *stm, struct stm_output *output)
+{
+	struct stp_master *master = stm_master(stm, output->master);
+
+	if (WARN_ON_ONCE(master->nr_free < output->nr_chans))
+		return;
+
+	bitmap_allocate_region(&master->chan_map[0], output->channel,
+			       ilog2(output->nr_chans));
+
+	master->nr_free -= output->nr_chans;
+}
+
+static void
+stm_output_disclaim(struct stm_device *stm, struct stm_output *output)
+{
+	struct stp_master *master = stm_master(stm, output->master);
+
+	bitmap_release_region(&master->chan_map[0], output->channel,
+			      ilog2(output->nr_chans));
+
+	output->nr_chans = 0;
+	master->nr_free += output->nr_chans;
+}
+
+/*
+ * This is like bitmap_find_free_region(), except it can ignore @start bits
+ * at the beginning.
+ */
+static int find_free_channels(unsigned long *bitmap, unsigned int start,
+			      unsigned int end, unsigned int width)
+{
+	unsigned int pos;
+	int i;
+
+	for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) {
+		pos = find_next_zero_bit(bitmap, end + 1, pos);
+		if (pos + width > end + 1)
+			break;
+
+		if (pos & (width - 1))
+			continue;
+
+		for (i = 1; i < width && !test_bit(pos + i, bitmap); i++)
+			;
+		if (i == width)
+			return pos;
+	}
+
+	return -1;
+}
+
+static unsigned int
+stm_find_master_chan(struct stm_device *stm, unsigned int width,
+		     unsigned int *mstart, unsigned int mend,
+		     unsigned int *cstart, unsigned int cend)
+{
+	struct stp_master *master;
+	unsigned int midx;
+	int pos, err;
+
+	for (midx = *mstart; midx <= mend; midx++) {
+		if (!stm_master(stm, midx)) {
+			err = stp_master_alloc(stm, midx);
+			if (err)
+				return err;
+		}
+
+		master = stm_master(stm, midx);
+
+		if (!master->nr_free)
+			continue;
+
+		pos = find_free_channels(master->chan_map, *cstart, cend,
+					 width);
+		if (pos < 0)
+			continue;
+
+		*mstart = midx;
+		*cstart = pos;
+		return 0;
+	}
+
+	return -ENOSPC;
+}
+
+static int stm_output_assign(struct stm_device *stm, unsigned int width,
+			     struct stp_policy_node *policy_node,
+			     struct stm_output *output)
+{
+	unsigned int midx, cidx, mend, cend;
+	int ret = -EINVAL;
+
+	if (width > stm->data->sw_nchannels)
+		return -EINVAL;
+
+	if (policy_node) {
+		stp_policy_node_get_ranges(policy_node,
+					   &midx, &mend, &cidx, &cend);
+	} else {
+		midx = stm->data->sw_start;
+		cidx = 0;
+		mend = stm->data->sw_end;
+		cend = stm->data->sw_nchannels - 1;
+	}
+
+	spin_lock(&stm->mc_lock);
+	/* output is already assigned -- shouldn't happen */
+	if (WARN_ON_ONCE(output->nr_chans))
+		goto unlock;
+
+	ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend);
+	if (ret)
+		goto unlock;
+
+	output->master = midx;
+	output->channel = cidx;
+	output->nr_chans = width;
+	stm_output_claim(stm, output);
+	dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width);
+
+	ret = 0;
+unlock:
+	spin_unlock(&stm->mc_lock);
+
+	return ret;
+}
+
+static void stm_output_free(struct stm_device *stm, struct stm_output *output)
+{
+	spin_lock(&stm->mc_lock);
+	if (output->nr_chans)
+		stm_output_disclaim(stm, output);
+	spin_unlock(&stm->mc_lock);
+}
+
+static int major_match(struct device *dev, const void *data)
+{
+	unsigned int major = *(unsigned int *)data;
+
+	return MAJOR(dev->devt) == major;
+}
+
+static int stm_char_open(struct inode *inode, struct file *file)
+{
+	struct stm_file *stmf;
+	struct device *dev;
+	unsigned int major = imajor(inode);
+	int err = -ENODEV;
+
+	dev = class_find_device(&stm_class, NULL, &major, major_match);
+	if (!dev)
+		return -ENODEV;
+
+	stmf = kzalloc(sizeof(*stmf), GFP_KERNEL);
+	if (!stmf)
+		return -ENOMEM;
+
+	stmf->stm = to_stm_device(dev);
+
+	if (!try_module_get(stmf->stm->owner))
+		goto err_free;
+
+	file->private_data = stmf;
+
+	return nonseekable_open(inode, file);
+
+err_free:
+	kfree(stmf);
+
+	return err;
+}
+
+static int stm_char_release(struct inode *inode, struct file *file)
+{
+	struct stm_file *stmf = file->private_data;
+
+	stm_output_free(stmf->stm, &stmf->output);
+	stm_put_device(stmf->stm);
+	kfree(stmf);
+
+	return 0;
+}
+
+static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width)
+{
+	struct stm_device *stm = stmf->stm;
+	int ret;
+
+	stmf->policy_node = stp_policy_node_lookup(stm, id);
+
+	ret = stm_output_assign(stm, width, stmf->policy_node, &stmf->output);
+
+	if (stmf->policy_node)
+		stp_policy_node_put(stmf->policy_node);
+
+	return ret;
+}
+
+static void stm_write(struct stm_data *data, unsigned int master,
+		      unsigned int channel, const char *buf, size_t count)
+{
+	unsigned int flags = STP_PACKET_TIMESTAMPED;
+	const unsigned char *p = buf, nil = 0;
+	size_t pos;
+	ssize_t sz;
+
+	for (pos = 0, p = buf; count > pos; pos += sz, p += sz) {
+		sz = min_t(unsigned int, count - pos, 8);
+		sz = data->packet(data, master, channel, STP_PACKET_DATA, flags,
+				  sz, p);
+		flags = 0;
+	}
+
+	data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil);
+}
+
+static ssize_t stm_char_write(struct file *file, const char __user *buf,
+			      size_t count, loff_t *ppos)
+{
+	struct stm_file *stmf = file->private_data;
+	struct stm_device *stm = stmf->stm;
+	char *kbuf;
+	int err;
+
+	/*
+	 * if no m/c have been assigned to this writer up to this
+	 * point, use "default" policy entry
+	 */
+	if (!stmf->output.nr_chans) {
+		err = stm_file_assign(stmf, "default", 1);
+		/*
+		 * EBUSY means that somebody else just assigned this
+		 * output, which is just fine for write()
+		 */
+		if (err && err != -EBUSY)
+			return err;
+	}
+
+	kbuf = kmalloc(count + 1, GFP_KERNEL);
+	if (!kbuf)
+		return -ENOMEM;
+
+	err = copy_from_user(kbuf, buf, count);
+	if (err) {
+		kfree(kbuf);
+		return -EFAULT;
+	}
+
+	stm_write(stm->data, stmf->output.master, stmf->output.channel, kbuf,
+		  count);
+
+	kfree(kbuf);
+
+	return count;
+}
+
+static int stm_char_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct stm_file *stmf = file->private_data;
+	struct stm_device *stm = stmf->stm;
+	unsigned long size, phys;
+
+	if (!stm->data->mmio_addr)
+		return -EOPNOTSUPP;
+
+	if (vma->vm_pgoff)
+		return -EINVAL;
+
+	size = vma->vm_end - vma->vm_start;
+
+	if (stmf->output.nr_chans * stm->data->sw_mmiosz != size)
+		return -EINVAL;
+
+	phys = stm->data->mmio_addr(stm->data, stmf->output.master,
+				    stmf->output.channel,
+				    stmf->output.nr_chans);
+
+	if (!phys)
+		return -EINVAL;
+
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+	vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
+	vm_iomap_memory(vma, phys, size);
+
+	return 0;
+}
+
+static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg)
+{
+	struct stm_device *stm = stmf->stm;
+	struct stp_policy_id *id;
+	int ret = -EINVAL;
+	u32 size;
+
+	if (stmf->output.nr_chans)
+		return -EBUSY;
+
+	if (copy_from_user(&size, arg, sizeof(size)))
+		return -EFAULT;
+
+	if (size >= PATH_MAX + sizeof(*id))
+		return -EINVAL;
+
+	/*
+	 * size + 1 to make sure the .id string at the bottom is terminated,
+	 * which is also why memdup_user() is not useful here
+	 */
+	id = kzalloc(size + 1, GFP_KERNEL);
+	if (!id)
+		return -ENOMEM;
+
+	if (copy_from_user(id, arg, size)) {
+		ret = -EFAULT;
+		goto err_free;
+	}
+
+	if (id->__reserved_0 || id->__reserved_1)
+		goto err_free;
+
+	if (id->width < 1 ||
+	    id->width > PAGE_SIZE / stm->data->sw_mmiosz)
+		goto err_free;
+
+	ret = stm_file_assign(stmf, id->id, id->width);
+	if (ret)
+		goto err_free;
+
+	ret = 0;
+
+	if (stm->data->link)
+		ret = stm->data->link(stm->data, stmf->output.master,
+				      stmf->output.channel);
+
+	if (ret) {
+		stm_output_free(stmf->stm, &stmf->output);
+		stm_put_device(stmf->stm);
+	}
+
+err_free:
+	kfree(id);
+
+	return ret;
+}
+
+static int stm_char_policy_get_ioctl(struct stm_file *stmf, void __user *arg)
+{
+	struct stp_policy_id id = {
+		.size		= sizeof(id),
+		.master		= stmf->output.master,
+		.channel	= stmf->output.channel,
+		.width		= stmf->output.nr_chans,
+		.__reserved_0	= 0,
+		.__reserved_1	= 0,
+	};
+
+	return copy_to_user(arg, &id, id.size) ? -EFAULT : 0;
+}
+
+static long
+stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct stm_file *stmf = file->private_data;
+	struct stm_data *stm_data = stmf->stm->data;
+	int err = -ENOTTY;
+	u64 options;
+
+	switch (cmd) {
+	case STP_POLICY_ID_SET:
+		err = stm_char_policy_set_ioctl(stmf, (void __user *)arg);
+		if (err)
+			return err;
+
+		return stm_char_policy_get_ioctl(stmf, (void __user *)arg);
+
+	case STP_POLICY_ID_GET:
+		return stm_char_policy_get_ioctl(stmf, (void __user *)arg);
+
+	case STP_SET_OPTIONS:
+		if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64)))
+			return -EFAULT;
+
+		if (stm_data->set_options)
+			err = stm_data->set_options(stm_data,
+						    stmf->output.master,
+						    stmf->output.channel,
+						    stmf->output.nr_chans,
+						    options);
+
+		break;
+	default:
+		break;
+	}
+
+	return err;
+}
+
+#ifdef CONFIG_COMPAT
+static long
+stm_char_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	return stm_char_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#else
+#define stm_char_compat_ioctl	NULL
+#endif
+
+static const struct file_operations stm_fops = {
+	.open		= stm_char_open,
+	.release	= stm_char_release,
+	.write		= stm_char_write,
+	.mmap		= stm_char_mmap,
+	.unlocked_ioctl	= stm_char_ioctl,
+	.compat_ioctl	= stm_char_compat_ioctl,
+	.llseek		= no_llseek,
+};
+
+static void stm_device_release(struct device *dev)
+{
+	struct stm_device *stm = to_stm_device(dev);
+
+	kfree(stm);
+}
+
+int stm_register_device(struct device *parent, struct stm_data *stm_data,
+			struct module *owner)
+{
+	struct stm_device *stm;
+	unsigned int nmasters;
+	int err = -ENOMEM;
+
+	if (!stm_core_up)
+		return -EPROBE_DEFER;
+
+	if (!stm_data->packet || !stm_data->sw_nchannels)
+		return -EINVAL;
+
+	nmasters = stm_data->sw_end - stm_data->sw_start;
+	stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL);
+	if (!stm)
+		return -ENOMEM;
+
+	stm->major = register_chrdev(0, stm_data->name, &stm_fops);
+	if (stm->major < 0)
+		goto err_free;
+
+	device_initialize(&stm->dev);
+	stm->dev.devt = MKDEV(stm->major, 0);
+	stm->dev.class = &stm_class;
+	stm->dev.parent = parent;
+	stm->dev.release = stm_device_release;
+
+	err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name);
+	if (err)
+		goto err_device;
+
+	err = device_add(&stm->dev);
+	if (err)
+		goto err_device;
+
+	spin_lock_init(&stm->link_lock);
+	INIT_LIST_HEAD(&stm->link_list);
+
+	spin_lock_init(&stm->mc_lock);
+	mutex_init(&stm->policy_mutex);
+	stm->sw_nmasters = nmasters;
+	stm->owner = owner;
+	stm->data = stm_data;
+	stm_data->stm = stm;
+
+	return 0;
+
+err_device:
+	put_device(&stm->dev);
+err_free:
+	kfree(stm);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(stm_register_device);
+
+static void __stm_source_link_drop(struct stm_source_device *src,
+				   struct stm_device *stm);
+
+void stm_unregister_device(struct stm_data *stm_data)
+{
+	struct stm_device *stm = stm_data->stm;
+	struct stm_source_device *src, *iter;
+	int i;
+
+	spin_lock(&stm->link_lock);
+	list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) {
+		__stm_source_link_drop(src, stm);
+	}
+	spin_unlock(&stm->link_lock);
+
+	synchronize_srcu(&stm_source_srcu);
+
+	unregister_chrdev(stm->major, stm_data->name);
+
+	mutex_lock(&stm->policy_mutex);
+	if (stm->policy)
+		stp_policy_unbind(stm->policy);
+	mutex_unlock(&stm->policy_mutex);
+
+	for (i = 0; i < stm->sw_nmasters; i++)
+		stp_master_free(stm, i);
+
+	device_unregister(&stm->dev);
+	stm_data->stm = NULL;
+}
+EXPORT_SYMBOL_GPL(stm_unregister_device);
+
+/**
+ * stm_source_link_add() - connect an stm_source device to an stm device
+ * @src:	stm_source device
+ * @stm:	stm device
+ *
+ * This function establishes a link from stm_source to an stm device so that
+ * the former can send out trace data to the latter.
+ *
+ * Return:	0 on success, -errno otherwise.
+ */
+static int stm_source_link_add(struct stm_source_device *src,
+			       struct stm_device *stm)
+{
+	char *id;
+	int err;
+
+	spin_lock(&stm->link_lock);
+	spin_lock(&src->link_lock);
+
+	/* src->link is dereferenced under stm_source_srcu but not the list */
+	rcu_assign_pointer(src->link, stm);
+	list_add_tail(&src->link_entry, &stm->link_list);
+
+	spin_unlock(&src->link_lock);
+	spin_unlock(&stm->link_lock);
+
+	id = kstrdup(src->data->name, GFP_KERNEL);
+	if (id) {
+		src->policy_node =
+			stp_policy_node_lookup(stm, id);
+
+		kfree(id);
+	}
+
+	err = stm_output_assign(stm, src->data->nr_chans,
+				src->policy_node, &src->output);
+
+	if (src->policy_node)
+		stp_policy_node_put(src->policy_node);
+
+	if (err)
+		goto fail_detach;
+
+	/* this is to notify the STM device that a new link has been made */
+	if (stm->data->link)
+		err = stm->data->link(stm->data, src->output.master,
+				      src->output.channel);
+
+	if (err)
+		goto fail_free_output;
+
+	/* this is to let the source carry out all necessary preparations */
+	if (src->data->link)
+		src->data->link(src->data);
+
+	return 0;
+
+fail_free_output:
+	stm_output_free(stm, &src->output);
+	stm_put_device(stm);
+
+fail_detach:
+	spin_lock(&stm->link_lock);
+	spin_lock(&src->link_lock);
+
+	rcu_assign_pointer(src->link, NULL);
+	list_del_init(&src->link_entry);
+
+	spin_unlock(&src->link_lock);
+	spin_unlock(&stm->link_lock);
+
+	return err;
+}
+
+/**
+ * __stm_source_link_drop() - detach stm_source from an stm device
+ * @src:	stm_source device
+ * @stm:	stm device
+ *
+ * If @stm is @src::link, disconnect them from one another and put the
+ * reference on the @stm device.
+ *
+ * Caller must hold stm::link_lock.
+ */
+static void __stm_source_link_drop(struct stm_source_device *src,
+				   struct stm_device *stm)
+{
+	struct stm_device *link;
+
+	spin_lock(&src->link_lock);
+	link = srcu_dereference_check(src->link, &stm_source_srcu, 1);
+	if (WARN_ON_ONCE(link != stm)) {
+		spin_unlock(&src->link_lock);
+		return;
+	}
+
+	stm_output_free(link, &src->output);
+	/* caller must hold stm::link_lock */
+	list_del_init(&src->link_entry);
+	/* matches stm_find_device() from stm_source_link_store() */
+	stm_put_device(link);
+	rcu_assign_pointer(src->link, NULL);
+
+	spin_unlock(&src->link_lock);
+}
+
+/**
+ * stm_source_link_drop() - detach stm_source from its stm device
+ * @src:	stm_source device
+ *
+ * Unlinking means disconnecting from source's STM device; after this
+ * writes will be unsuccessful until it is linked to a new STM device.
+ *
+ * This will happen on "stm_source_link" sysfs attribute write to undo
+ * the existing link (if any), or on linked STM device's de-registration.
+ */
+static void stm_source_link_drop(struct stm_source_device *src)
+{
+	struct stm_device *stm;
+	int idx;
+
+	idx = srcu_read_lock(&stm_source_srcu);
+	stm = srcu_dereference(src->link, &stm_source_srcu);
+
+	if (stm) {
+		if (src->data->unlink)
+			src->data->unlink(src->data);
+
+		spin_lock(&stm->link_lock);
+		__stm_source_link_drop(src, stm);
+		spin_unlock(&stm->link_lock);
+	}
+
+	srcu_read_unlock(&stm_source_srcu, idx);
+}
+
+static ssize_t stm_source_link_show(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	struct stm_source_device *src = to_stm_source_device(dev);
+	struct stm_device *stm;
+	int idx, ret;
+
+	idx = srcu_read_lock(&stm_source_srcu);
+	stm = srcu_dereference(src->link, &stm_source_srcu);
+	ret = sprintf(buf, "%s\n",
+		      stm ? dev_name(&stm->dev) : "<none>");
+	srcu_read_unlock(&stm_source_srcu, idx);
+
+	return ret;
+}
+
+static ssize_t stm_source_link_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct stm_source_device *src = to_stm_source_device(dev);
+	struct stm_device *link;
+	int err;
+
+	stm_source_link_drop(src);
+
+	link = stm_find_device(buf);
+	if (!link)
+		return -EINVAL;
+
+	err = stm_source_link_add(src, link);
+	if (err)
+		stm_put_device(link);
+
+	return err ? : count;
+}
+
+static DEVICE_ATTR_RW(stm_source_link);
+
+static struct attribute *stm_source_attrs[] = {
+	&dev_attr_stm_source_link.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(stm_source);
+
+static struct class stm_source_class = {
+	.name		= "stm_source",
+	.dev_groups	= stm_source_groups,
+};
+
+static void stm_source_device_release(struct device *dev)
+{
+	struct stm_source_device *src = to_stm_source_device(dev);
+
+	kfree(src);
+}
+
+/**
+ * stm_source_register_device() - register an stm_source device
+ * @parent:	parent device
+ * @data:	device description structure
+ *
+ * This will create a device of stm_source class that can write
+ * data to an stm device once linked.
+ *
+ * Return:	0 on success, -errno otherwise.
+ */
+int stm_source_register_device(struct device *parent,
+			       struct stm_source_data *data)
+{
+	struct stm_source_device *src;
+	int err;
+
+	if (!stm_core_up)
+		return -EPROBE_DEFER;
+
+	src = kzalloc(sizeof(*src), GFP_KERNEL);
+	if (!src)
+		return -ENOMEM;
+
+	device_initialize(&src->dev);
+	src->dev.class = &stm_source_class;
+	src->dev.parent = parent;
+	src->dev.release = stm_source_device_release;
+
+	err = kobject_set_name(&src->dev.kobj, "%s", data->name);
+	if (err)
+		goto err;
+
+	err = device_add(&src->dev);
+	if (err)
+		goto err;
+
+	spin_lock_init(&src->link_lock);
+	INIT_LIST_HEAD(&src->link_entry);
+	src->data = data;
+	data->src = src;
+
+	return 0;
+
+err:
+	put_device(&src->dev);
+	kfree(src);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(stm_source_register_device);
+
+/**
+ * stm_source_unregister_device() - unregister an stm_source device
+ * @data:	device description that was used to register the device
+ *
+ * This will remove a previously created stm_source device from the system.
+ */
+void stm_source_unregister_device(struct stm_source_data *data)
+{
+	struct stm_source_device *src = data->src;
+
+	stm_source_link_drop(src);
+
+	device_destroy(&stm_source_class, src->dev.devt);
+}
+EXPORT_SYMBOL_GPL(stm_source_unregister_device);
+
+int stm_source_write(struct stm_source_data *data, unsigned int chan,
+		     const char *buf, size_t count)
+{
+	struct stm_source_device *src = data->src;
+	struct stm_device *stm;
+	int idx;
+
+	if (!src->output.nr_chans)
+		return -ENODEV;
+
+	if (chan >= src->output.nr_chans)
+		return -EINVAL;
+
+	idx = srcu_read_lock(&stm_source_srcu);
+
+	stm = srcu_dereference(src->link, &stm_source_srcu);
+	if (stm)
+		stm_write(stm->data, src->output.master,
+			  src->output.channel + chan,
+			  buf, count);
+	else
+		count = -ENODEV;
+
+	srcu_read_unlock(&stm_source_srcu, idx);
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(stm_source_write);
+
+static int __init stm_core_init(void)
+{
+	int err;
+
+	err = class_register(&stm_class);
+	if (err)
+		return err;
+
+	err = class_register(&stm_source_class);
+	if (err)
+		goto err_stm;
+
+	err = stp_configfs_init();
+	if (err)
+		goto err_src;
+
+	init_srcu_struct(&stm_source_srcu);
+
+	stm_core_up++;
+
+	return 0;
+
+err_src:
+	class_unregister(&stm_source_class);
+err_stm:
+	class_unregister(&stm_class);
+
+	return err;
+}
+
+module_init(stm_core_init);
+
+static void __exit stm_core_exit(void)
+{
+	cleanup_srcu_struct(&stm_source_srcu);
+	class_unregister(&stm_source_class);
+	class_unregister(&stm_class);
+	stp_configfs_exit();
+}
+
+module_exit(stm_core_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("System Trace Module device class");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
diff --git a/drivers/hwtracing/stm/dummy_stm.c b/drivers/hwtracing/stm/dummy_stm.c
new file mode 100644
index 000000000000..3709bef0b21f
--- /dev/null
+++ b/drivers/hwtracing/stm/dummy_stm.c
@@ -0,0 +1,66 @@
+/*
+ * A dummy STM device for stm/stm_source class testing.
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * STM class implements generic infrastructure for  System Trace Module devices
+ * as defined in MIPI STPv2 specification.
+ */
+
+#undef DEBUG
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/stm.h>
+
+static ssize_t
+dummy_stm_packet(struct stm_data *stm_data, unsigned int master,
+		 unsigned int channel, unsigned int packet, unsigned int flags,
+		 unsigned int size, const unsigned char *payload)
+{
+#ifdef DEBUG
+	u64 pl = 0;
+
+	if (payload)
+		pl = *(u64 *)payload;
+
+	if (size < 8)
+		pl &= (1ull << (size * 8)) - 1;
+	trace_printk("[%u:%u] [pkt: %x/%x] (%llx)\n", master, channel,
+		     packet, size, pl);
+#endif
+	return size;
+}
+
+static struct stm_data dummy_stm = {
+	.name		= "dummy_stm",
+	.sw_start	= 0x0000,
+	.sw_end		= 0xffff,
+	.sw_nchannels	= 0xffff,
+	.packet		= dummy_stm_packet,
+};
+
+static int dummy_stm_init(void)
+{
+	return stm_register_device(NULL, &dummy_stm, THIS_MODULE);
+}
+
+static void dummy_stm_exit(void)
+{
+	stm_unregister_device(&dummy_stm);
+}
+
+module_init(dummy_stm_init);
+module_exit(dummy_stm_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("dummy_stm device");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
diff --git a/drivers/hwtracing/stm/policy.c b/drivers/hwtracing/stm/policy.c
new file mode 100644
index 000000000000..6498a9dbb7bd
--- /dev/null
+++ b/drivers/hwtracing/stm/policy.c
@@ -0,0 +1,529 @@
+/*
+ * System Trace Module (STM) master/channel allocation policy management
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * A master/channel allocation policy allows mapping string identifiers to
+ * master and channel ranges, where allocation can be done.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/configfs.h>
+#include <linux/slab.h>
+#include <linux/stm.h>
+#include "stm.h"
+
+/*
+ * STP Master/Channel allocation policy configfs layout.
+ */
+
+struct stp_policy {
+	struct config_group	group;
+	struct stm_device	*stm;
+};
+
+struct stp_policy_node {
+	struct config_group	group;
+	struct stp_policy	*policy;
+	unsigned int		first_master;
+	unsigned int		last_master;
+	unsigned int		first_channel;
+	unsigned int		last_channel;
+};
+
+static struct configfs_subsystem stp_policy_subsys;
+
+void stp_policy_node_get_ranges(struct stp_policy_node *policy_node,
+				unsigned int *mstart, unsigned int *mend,
+				unsigned int *cstart, unsigned int *cend)
+{
+	*mstart	= policy_node->first_master;
+	*mend	= policy_node->last_master;
+	*cstart	= policy_node->first_channel;
+	*cend	= policy_node->last_channel;
+}
+
+static inline char *stp_policy_node_name(struct stp_policy_node *policy_node)
+{
+	return policy_node->group.cg_item.ci_name ? : "<none>";
+}
+
+static inline struct stp_policy *to_stp_policy(struct config_item *item)
+{
+	return item ?
+		container_of(to_config_group(item), struct stp_policy, group) :
+		NULL;
+}
+
+static inline struct stp_policy_node *
+to_stp_policy_node(struct config_item *item)
+{
+	return item ?
+		container_of(to_config_group(item), struct stp_policy_node,
+			     group) :
+		NULL;
+}
+
+static ssize_t stp_policy_node_masters_show(struct stp_policy_node *policy_node,
+					    char *page)
+{
+	ssize_t count;
+
+	count = sprintf(page, "%u %u\n", policy_node->first_master,
+			policy_node->last_master);
+
+	return count;
+}
+
+static ssize_t
+stp_policy_node_masters_store(struct stp_policy_node *policy_node,
+			      const char *page, size_t count)
+{
+	unsigned int first, last;
+	struct stm_device *stm;
+	char *p = (char *)page;
+	ssize_t ret = -ENODEV;
+
+	if (sscanf(p, "%u %u", &first, &last) != 2)
+		return -EINVAL;
+
+	mutex_lock(&stp_policy_subsys.su_mutex);
+	stm = policy_node->policy->stm;
+	if (!stm)
+		goto unlock;
+
+	/* must be within [sw_start..sw_end], which is an inclusive range */
+	if (first > INT_MAX || last > INT_MAX || first > last ||
+	    first < stm->data->sw_start ||
+	    last > stm->data->sw_end) {
+		ret = -ERANGE;
+		goto unlock;
+	}
+
+	ret = count;
+	policy_node->first_master = first;
+	policy_node->last_master = last;
+
+unlock:
+	mutex_unlock(&stp_policy_subsys.su_mutex);
+
+	return ret;
+}
+
+static ssize_t
+stp_policy_node_channels_show(struct stp_policy_node *policy_node, char *page)
+{
+	ssize_t count;
+
+	count = sprintf(page, "%u %u\n", policy_node->first_channel,
+			policy_node->last_channel);
+
+	return count;
+}
+
+static ssize_t
+stp_policy_node_channels_store(struct stp_policy_node *policy_node,
+			       const char *page, size_t count)
+{
+	unsigned int first, last;
+	struct stm_device *stm;
+	char *p = (char *)page;
+	ssize_t ret = -ENODEV;
+
+	if (sscanf(p, "%u %u", &first, &last) != 2)
+		return -EINVAL;
+
+	mutex_lock(&stp_policy_subsys.su_mutex);
+	stm = policy_node->policy->stm;
+	if (!stm)
+		goto unlock;
+
+	if (first > INT_MAX || last > INT_MAX || first > last ||
+	    last >= stm->data->sw_nchannels) {
+		ret = -ERANGE;
+		goto unlock;
+	}
+
+	ret = count;
+	policy_node->first_channel = first;
+	policy_node->last_channel = last;
+
+unlock:
+	mutex_unlock(&stp_policy_subsys.su_mutex);
+
+	return ret;
+}
+
+static void stp_policy_node_release(struct config_item *item)
+{
+	kfree(to_stp_policy_node(item));
+}
+
+struct stp_policy_node_attribute {
+	struct configfs_attribute	attr;
+	ssize_t (*show)(struct stp_policy_node *, char *);
+	ssize_t (*store)(struct stp_policy_node *, const char *, size_t);
+};
+
+static ssize_t stp_policy_node_attr_show(struct config_item *item,
+					 struct configfs_attribute *attr,
+					 char *page)
+{
+	struct stp_policy_node *policy_node = to_stp_policy_node(item);
+	struct stp_policy_node_attribute *pn_attr =
+		container_of(attr, struct stp_policy_node_attribute, attr);
+	ssize_t count = 0;
+
+	if (pn_attr->show)
+		count = pn_attr->show(policy_node, page);
+
+	return count;
+}
+
+static ssize_t stp_policy_node_attr_store(struct config_item *item,
+					  struct configfs_attribute *attr,
+					  const char *page, size_t len)
+{
+	struct stp_policy_node *policy_node = to_stp_policy_node(item);
+	struct stp_policy_node_attribute *pn_attr =
+		container_of(attr, struct stp_policy_node_attribute, attr);
+	ssize_t count = -EINVAL;
+
+	if (pn_attr->store)
+		count = pn_attr->store(policy_node, page, len);
+
+	return count;
+}
+
+static struct configfs_item_operations stp_policy_node_item_ops = {
+	.release		= stp_policy_node_release,
+	.show_attribute		= stp_policy_node_attr_show,
+	.store_attribute	= stp_policy_node_attr_store,
+};
+
+static struct stp_policy_node_attribute stp_policy_node_attr_range = {
+	.attr	= {
+		.ca_owner = THIS_MODULE,
+		.ca_name = "masters",
+		.ca_mode = S_IRUGO | S_IWUSR,
+	},
+	.show	= stp_policy_node_masters_show,
+	.store	= stp_policy_node_masters_store,
+};
+
+static struct stp_policy_node_attribute stp_policy_node_attr_channels = {
+	.attr	= {
+		.ca_owner = THIS_MODULE,
+		.ca_name = "channels",
+		.ca_mode = S_IRUGO | S_IWUSR,
+	},
+	.show	= stp_policy_node_channels_show,
+	.store	= stp_policy_node_channels_store,
+};
+
+static struct configfs_attribute *stp_policy_node_attrs[] = {
+	&stp_policy_node_attr_range.attr,
+	&stp_policy_node_attr_channels.attr,
+	NULL,
+};
+
+static struct config_item_type stp_policy_type;
+static struct config_item_type stp_policy_node_type;
+
+static struct config_group *
+stp_policy_node_make(struct config_group *group, const char *name)
+{
+	struct stp_policy_node *policy_node, *parent_node;
+	struct stp_policy *policy;
+
+	if (group->cg_item.ci_type == &stp_policy_type) {
+		policy = container_of(group, struct stp_policy, group);
+	} else {
+		parent_node = container_of(group, struct stp_policy_node,
+					   group);
+		policy = parent_node->policy;
+	}
+
+	if (!policy->stm)
+		return ERR_PTR(-ENODEV);
+
+	policy_node = kzalloc(sizeof(struct stp_policy_node), GFP_KERNEL);
+	if (!policy_node)
+		return ERR_PTR(-ENOMEM);
+
+	config_group_init_type_name(&policy_node->group, name,
+				    &stp_policy_node_type);
+
+	policy_node->policy = policy;
+
+	/* default values for the attributes */
+	policy_node->first_master = policy->stm->data->sw_start;
+	policy_node->last_master = policy->stm->data->sw_end;
+	policy_node->first_channel = 0;
+	policy_node->last_channel = policy->stm->data->sw_nchannels - 1;
+
+	return &policy_node->group;
+}
+
+static void
+stp_policy_node_drop(struct config_group *group, struct config_item *item)
+{
+	config_item_put(item);
+}
+
+static struct configfs_group_operations stp_policy_node_group_ops = {
+	.make_group	= stp_policy_node_make,
+	.drop_item	= stp_policy_node_drop,
+};
+
+static struct config_item_type stp_policy_node_type = {
+	.ct_item_ops	= &stp_policy_node_item_ops,
+	.ct_group_ops	= &stp_policy_node_group_ops,
+	.ct_attrs	= stp_policy_node_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+/*
+ * Root group: policies.
+ */
+static struct configfs_attribute stp_policy_attr_device = {
+	.ca_owner = THIS_MODULE,
+	.ca_name = "device",
+	.ca_mode = S_IRUGO,
+};
+
+static struct configfs_attribute *stp_policy_attrs[] = {
+	&stp_policy_attr_device,
+	NULL,
+};
+
+static ssize_t stp_policy_attr_show(struct config_item *item,
+				    struct configfs_attribute *attr,
+				    char *page)
+{
+	struct stp_policy *policy = to_stp_policy(item);
+	ssize_t count;
+
+	count = sprintf(page, "%s\n",
+			(policy && policy->stm) ?
+			policy->stm->data->name :
+			"<none>");
+
+	return count;
+}
+
+void stp_policy_unbind(struct stp_policy *policy)
+{
+	struct stm_device *stm = policy->stm;
+
+	if (WARN_ON_ONCE(!policy->stm))
+		return;
+
+	mutex_lock(&stm->policy_mutex);
+	stm->policy = NULL;
+	mutex_unlock(&stm->policy_mutex);
+
+	policy->stm = NULL;
+
+	stm_put_device(stm);
+}
+
+static void stp_policy_release(struct config_item *item)
+{
+	struct stp_policy *policy = to_stp_policy(item);
+
+	stp_policy_unbind(policy);
+	kfree(policy);
+}
+
+static struct configfs_item_operations stp_policy_item_ops = {
+	.release		= stp_policy_release,
+	.show_attribute		= stp_policy_attr_show,
+};
+
+static struct configfs_group_operations stp_policy_group_ops = {
+	.make_group	= stp_policy_node_make,
+};
+
+static struct config_item_type stp_policy_type = {
+	.ct_item_ops	= &stp_policy_item_ops,
+	.ct_group_ops	= &stp_policy_group_ops,
+	.ct_attrs	= stp_policy_attrs,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct config_group *
+stp_policies_make(struct config_group *group, const char *name)
+{
+	struct config_group *ret;
+	struct stm_device *stm;
+	char *devname, *p;
+
+	devname = kasprintf(GFP_KERNEL, "%s", name);
+	if (!devname)
+		return ERR_PTR(-ENOMEM);
+
+	/*
+	 * node must look like <device_name>.<policy_name>, where
+	 * <device_name> is the name of an existing stm device and
+	 * <policy_name> is an arbitrary string
+	 */
+	p = strchr(devname, '.');
+	if (!p) {
+		kfree(devname);
+		return ERR_PTR(-EINVAL);
+	}
+
+	*p++ = '\0';
+
+	stm = stm_find_device(devname);
+	kfree(devname);
+
+	if (!stm)
+		return ERR_PTR(-ENODEV);
+
+	mutex_lock(&stm->policy_mutex);
+	if (stm->policy) {
+		ret = ERR_PTR(-EBUSY);
+		goto unlock_policy;
+	}
+
+	stm->policy = kzalloc(sizeof(*stm->policy), GFP_KERNEL);
+	if (!stm->policy) {
+		ret = ERR_PTR(-ENOMEM);
+		goto unlock_policy;
+	}
+
+	config_group_init_type_name(&stm->policy->group, name,
+				    &stp_policy_type);
+	stm->policy->stm = stm;
+
+	ret = &stm->policy->group;
+
+unlock_policy:
+	mutex_unlock(&stm->policy_mutex);
+
+	if (IS_ERR(ret))
+		stm_put_device(stm);
+
+	return ret;
+}
+
+static struct configfs_group_operations stp_policies_group_ops = {
+	.make_group	= stp_policies_make,
+};
+
+static struct config_item_type stp_policies_type = {
+	.ct_group_ops	= &stp_policies_group_ops,
+	.ct_owner	= THIS_MODULE,
+};
+
+static struct configfs_subsystem stp_policy_subsys = {
+	.su_group = {
+		.cg_item = {
+			.ci_namebuf	= "stp-policy",
+			.ci_type	= &stp_policies_type,
+		},
+	},
+};
+
+/*
+ * Lock the policy mutex from the outside
+ */
+static struct stp_policy_node *
+__stp_policy_node_lookup(struct stp_policy *policy, char *s)
+{
+	struct stp_policy_node *policy_node, *ret;
+	struct list_head *head = &policy->group.cg_children;
+	struct config_item *item;
+	char *start, *end = s;
+
+	if (list_empty(head))
+		return NULL;
+
+	/* return the first entry if everything else fails */
+	item = list_entry(head->next, struct config_item, ci_entry);
+	ret = to_stp_policy_node(item);
+
+next:
+	for (;;) {
+		start = strsep(&end, "/");
+		if (!start)
+			break;
+
+		if (!*start)
+			continue;
+
+		list_for_each_entry(item, head, ci_entry) {
+			policy_node = to_stp_policy_node(item);
+
+			if (!strcmp(start,
+				    policy_node->group.cg_item.ci_name)) {
+				ret = policy_node;
+
+				if (!end)
+					goto out;
+
+				head = &policy_node->group.cg_children;
+				goto next;
+			}
+		}
+		break;
+	}
+
+out:
+	return ret;
+}
+
+
+struct stp_policy_node *
+stp_policy_node_lookup(struct stm_device *stm, char *s)
+{
+	struct stp_policy_node *policy_node = NULL;
+
+	mutex_lock(&stp_policy_subsys.su_mutex);
+
+	mutex_lock(&stm->policy_mutex);
+	if (stm->policy)
+		policy_node = __stp_policy_node_lookup(stm->policy, s);
+	mutex_unlock(&stm->policy_mutex);
+
+	if (policy_node)
+		config_item_get(&policy_node->group.cg_item);
+	mutex_unlock(&stp_policy_subsys.su_mutex);
+
+	return policy_node;
+}
+
+void stp_policy_node_put(struct stp_policy_node *policy_node)
+{
+	config_item_put(&policy_node->group.cg_item);
+}
+
+int __init stp_configfs_init(void)
+{
+	int err;
+
+	config_group_init(&stp_policy_subsys.su_group);
+	mutex_init(&stp_policy_subsys.su_mutex);
+	err = configfs_register_subsystem(&stp_policy_subsys);
+
+	return err;
+}
+
+void __exit stp_configfs_exit(void)
+{
+	configfs_unregister_subsystem(&stp_policy_subsys);
+}
diff --git a/drivers/hwtracing/stm/stm.h b/drivers/hwtracing/stm/stm.h
new file mode 100644
index 000000000000..95ece0292c99
--- /dev/null
+++ b/drivers/hwtracing/stm/stm.h
@@ -0,0 +1,87 @@
+/*
+ * System Trace Module (STM) infrastructure
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * STM class implements generic infrastructure for  System Trace Module devices
+ * as defined in MIPI STPv2 specification.
+ */
+
+#ifndef _STM_STM_H_
+#define _STM_STM_H_
+
+struct stp_policy;
+struct stp_policy_node;
+
+struct stp_policy_node *
+stp_policy_node_lookup(struct stm_device *stm, char *s);
+void stp_policy_node_put(struct stp_policy_node *policy_node);
+void stp_policy_unbind(struct stp_policy *policy);
+
+void stp_policy_node_get_ranges(struct stp_policy_node *policy_node,
+				unsigned int *mstart, unsigned int *mend,
+				unsigned int *cstart, unsigned int *cend);
+int stp_configfs_init(void);
+void stp_configfs_exit(void);
+
+struct stp_master {
+	unsigned int	nr_free;
+	unsigned long	chan_map[0];
+};
+
+struct stm_device {
+	struct device		dev;
+	struct module		*owner;
+	struct stp_policy	*policy;
+	struct mutex		policy_mutex;
+	int			major;
+	unsigned int		sw_nmasters;
+	struct stm_data		*data;
+	spinlock_t		link_lock;
+	struct list_head	link_list;
+	/* master allocation */
+	spinlock_t		mc_lock;
+	struct stp_master	*masters[0];
+};
+
+#define to_stm_device(_d)				\
+	container_of((_d), struct stm_device, dev)
+
+struct stm_output {
+	unsigned int		master;
+	unsigned int		channel;
+	unsigned int		nr_chans;
+};
+
+struct stm_file {
+	struct stm_device	*stm;
+	struct stp_policy_node	*policy_node;
+	struct stm_output	output;
+};
+
+struct stm_device *stm_find_device(const char *name);
+void stm_put_device(struct stm_device *stm);
+
+struct stm_source_device {
+	struct device		dev;
+	struct stm_source_data	*data;
+	spinlock_t		link_lock;
+	struct stm_device __rcu	*link;
+	struct list_head	link_entry;
+	/* one output per stm_source device */
+	struct stp_policy_node	*policy_node;
+	struct stm_output	output;
+};
+
+#define to_stm_source_device(_d)				\
+	container_of((_d), struct stm_source_device, dev)
+
+#endif /* _STM_STM_H_ */