diff --git a/Documentation/ABI/testing/configfs-stp-policy b/Documentation/ABI/testing/configfs-stp-policy
new file mode 100644
index 0000000000000000000000000000000000000000..421ce6825c665bc1a46d557bb2d6ac8e9b6585c0
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-stp-policy
@@ -0,0 +1,48 @@
+What: /config/stp-policy
+Date: June 2015
+KernelVersion: 4.3
+Description:
+ This group contains policies mandating Master/Channel allocation
+ for software sources wishing to send trace data over an STM
+ device.
+
+What: /config/stp-policy/<device>.<policy>
+Date: June 2015
+KernelVersion: 4.3
+Description:
+ This group is the root of a policy; its name is a concatenation
+ of an stm device name to which this policy applies and an
+ arbitrary string. If <device> part doesn't match an existing
+ stm device, mkdir will fail with ENODEV; if that device already
+ has a policy assigned to it, mkdir will fail with EBUSY.
+
+What: /config/stp-policy/<device>.<policy>/device
+Date: June 2015
+KernelVersion: 4.3
+Description:
+ STM device to which this policy applies, read only. Same as the
+ <device> component of its parent directory.
+
+What: /config/stp-policy/<device>.<policy>/<node>
+Date: June 2015
+KernelVersion: 4.3
+Description:
+ Policy node is a string identifier that software clients will
+ use to request a master/channel to be allocated and assigned to
+ them.
+
+What: /config/stp-policy/<device>.<policy>/<node>/masters
+Date: June 2015
+KernelVersion: 4.3
+Description:
+ Range of masters from which to allocate for users of this node.
+ Write two numbers: the first master and the last master number.
+
+What: /config/stp-policy/<device>.<policy>/<node>/channels
+Date: June 2015
+KernelVersion: 4.3
+Description:
+ Range of channels from which to allocate for users of this node.
+ Write two numbers: the first channel and the last channel
+ number.
+
diff --git a/Documentation/ABI/testing/sysfs-class-stm b/Documentation/ABI/testing/sysfs-class-stm
new file mode 100644
index 0000000000000000000000000000000000000000..c9aa4f3fc9a71f7429210346a61a727753ed724e
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-stm
@@ -0,0 +1,14 @@
+What: /sys/class/stm/<stm>/masters
+Date: June 2015
+KernelVersion: 4.3
+Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
+Description:
+ Shows first and last available to software master numbers on
+ this STM device.
+
+What: /sys/class/stm/<stm>/channels
+Date: June 2015
+KernelVersion: 4.3
+Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
+Description:
+ Shows the number of channels per master on this STM device.
diff --git a/Documentation/ABI/testing/sysfs-class-stm_source b/Documentation/ABI/testing/sysfs-class-stm_source
new file mode 100644
index 0000000000000000000000000000000000000000..57b8dd39bbf7e6beddfd198fe3cbeed1ad47514f
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-stm_source
@@ -0,0 +1,11 @@
+What: /sys/class/stm_source/<stm_source>/stm_source_link
+Date: June 2015
+KernelVersion: 4.3
+Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
+Description:
+ stm_source device linkage to stm device, where its tracing data
+ is directed. Reads return an existing connection or "<none>" if
+ this stm_source is not connected to any stm device yet.
+ Write an existing (registered) stm device's name here to
+ connect that device. If a device is already connected to this
+ stm_source, it will first be disconnected.
diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index df1b25eb838296f8fbc09d98459ec674f507e4eb..3785b7e131f86e8d1869027ab46938ee66b177e2 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -81,6 +81,9 @@ Code Seq#(hex) Include File Comments
0x22 all scsi/sg.h
'#' 00-3F IEEE 1394 Subsystem Block for the entire subsystem
'$' 00-0F linux/perf_counter.h, linux/perf_event.h
+'%' 00-0F include/uapi/linux/stm.h
+ System Trace Module subsystem
+ <mailto:alexander.shishkin@linux.intel.com>
'&' 00-07 drivers/firewire/nosy-user.h
'1' 00-1F <linux/timepps.h> PPS kit from Ulrich Windl
<ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>
diff --git a/Documentation/trace/stm.txt b/Documentation/trace/stm.txt
new file mode 100644
index 0000000000000000000000000000000000000000..ea035f9dbfd737134fb90f1aba32f66799ea0101
--- /dev/null
+++ b/Documentation/trace/stm.txt
@@ -0,0 +1,80 @@
+System Trace Module
+===================
+
+System Trace Module (STM) is a device described in MIPI STP specs as
+STP trace stream generator. STP (System Trace Protocol) is a trace
+protocol multiplexing data from multiple trace sources, each one of
+which is assigned a unique pair of master and channel. While some of
+these masters and channels are statically allocated to certain
+hardware trace sources, others are available to software. Software
+trace sources are usually free to pick for themselves any
+master/channel combination from this pool.
+
+On the receiving end of this STP stream (the decoder side), trace
+sources can only be identified by master/channel combination, so in
+order for the decoder to be able to make sense of the trace that
+involves multiple trace sources, it needs to be able to map those
+master/channel pairs to the trace sources that it understands.
+
+For instance, it is helpful to know that syslog messages come on
+master 7 channel 15, while arbitrary user applications can use masters
+48 to 63 and channels 0 to 127.
+
+To solve this mapping problem, stm class provides a policy management
+mechanism via configfs, that allows defining rules that map string
+identifiers to ranges of masters and channels. If these rules (policy)
+are consistent with what decoder expects, it will be able to properly
+process the trace data.
+
+This policy is a tree structure containing rules (policy_node) that
+have a name (string identifier) and a range of masters and channels
+associated with it, located in "stp-policy" subsystem directory in
+configfs. The topmost directory's name (the policy) is formatted as
+the STM device name to which this policy applies and and arbitrary
+string identifier separated by a stop. From the examle above, a rule
+may look like this:
+
+$ ls /config/stp-policy/dummy_stm.my-policy/user
+channels masters
+$ cat /config/stp-policy/dummy_stm.my-policy/user/masters
+48 63
+$ cat /config/stp-policy/dummy_stm.my-policy/user/channels
+0 127
+
+which means that the master allocation pool for this rule consists of
+masters 48 through 63 and channel allocation pool has channels 0
+through 127 in it. Now, any producer (trace source) identifying itself
+with "user" identification string will be allocated a master and
+channel from within these ranges.
+
+These rules can be nested, for example, one can define a rule "dummy"
+under "user" directory from the example above and this new rule will
+be used for trace sources with the id string of "user/dummy".
+
+Trace sources have to open the stm class device's node and write their
+trace data into its file descriptor. In order to identify themselves
+to the policy, they need to do a STP_POLICY_ID_SET ioctl on this file
+descriptor providing their id string. Otherwise, they will be
+automatically allocated a master/channel pair upon first write to this
+file descriptor according to the "default" rule of the policy, if such
+exists.
+
+Some STM devices may allow direct mapping of the channel mmio regions
+to userspace for zero-copy writing. One mappable page (in terms of
+mmu) will usually contain multiple channels' mmios, so the user will
+need to allocate that many channels to themselves (via the
+aforementioned ioctl() call) to be able to do this. That is, if your
+stm device's channel mmio region is 64 bytes and hardware page size is
+4096 bytes, after a successful STP_POLICY_ID_SET ioctl() call with
+width==64, you should be able to mmap() one page on this file
+descriptor and obtain direct access to an mmio region for 64 channels.
+
+For kernel-based trace sources, there is "stm_source" device
+class. Devices of this class can be connected and disconnected to/from
+stm devices at runtime via a sysfs attribute.
+
+Examples of STM devices are Intel(R) Trace Hub [1] and Coresight STM
+[2].
+
+[1] https://software.intel.com/sites/default/files/managed/d3/3c/intel-th-developer-manual.pdf
+[2] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0444b/index.html
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 46b4a8e0f8598bb2216f74dac47cd58c7afa66d2..b6e1cea63f8195457a69eafb24509f137651398d 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -188,4 +188,6 @@ source "drivers/nvdimm/Kconfig"
source "drivers/nvmem/Kconfig"
+source "drivers/hwtracing/stm/Kconfig"
+
endmenu
diff --git a/drivers/Makefile b/drivers/Makefile
index b250b36b54f26690840ffdd47d0c96bfc3aec7b6..e71b5e2a2c71c18b93718379f55372835b9cc1e4 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -165,5 +165,6 @@ obj-$(CONFIG_PERF_EVENTS) += perf/
obj-$(CONFIG_RAS) += ras/
obj-$(CONFIG_THUNDERBOLT) += thunderbolt/
obj-$(CONFIG_CORESIGHT) += hwtracing/coresight/
+obj-$(CONFIG_STM) += hwtracing/stm/
obj-$(CONFIG_ANDROID) += android/
obj-$(CONFIG_NVMEM) += nvmem/
diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig
new file mode 100644
index 0000000000000000000000000000000000000000..e101cb4f8e43096059df7c820177f8007b7b82af
--- /dev/null
+++ b/drivers/hwtracing/stm/Kconfig
@@ -0,0 +1,8 @@
+config STM
+ tristate "System Trace Module devices"
+ help
+ A System Trace Module (STM) is a device exporting data in System
+ Trace Protocol (STP) format as defined by MIPI STP standards.
+ Examples of such devices are Intel(R) Trace Hub and Coresight STM.
+
+ Say Y here to enable System Trace Module device support.
diff --git a/drivers/hwtracing/stm/Makefile b/drivers/hwtracing/stm/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..adec7016499fad34564968ccb93afda3774aa5d3
--- /dev/null
+++ b/drivers/hwtracing/stm/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_STM) += stm_core.o
+
+stm_core-y := core.o policy.o
diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c
new file mode 100644
index 0000000000000000000000000000000000000000..b79c42c62557fea294e9156717024b5fd108159f
--- /dev/null
+++ b/drivers/hwtracing/stm/core.c
@@ -0,0 +1,1029 @@
+/*
+ * 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)
+{
+ spin_lock(&src->link_lock);
+ if (WARN_ON_ONCE(src->link != stm)) {
+ spin_unlock(&src->link_lock);
+ return;
+ }
+
+ stm_output_free(src->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(src->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/policy.c b/drivers/hwtracing/stm/policy.c
new file mode 100644
index 0000000000000000000000000000000000000000..6498a9dbb7bd184802c6f270548c417b24e38e2d
--- /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 0000000000000000000000000000000000000000..cf33bf976abed90e46cdfecd6532e6fc078d53b2
--- /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 *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_ */
diff --git a/include/linux/stm.h b/include/linux/stm.h
new file mode 100644
index 0000000000000000000000000000000000000000..9d0083d364e642b6ac68ae56cdae3bc197ffebde
--- /dev/null
+++ b/include/linux/stm.h
@@ -0,0 +1,126 @@
+/*
+ * System Trace Module (STM) infrastructure apis
+ * 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.
+ */
+
+#ifndef _STM_H_
+#define _STM_H_
+
+#include <linux/device.h>
+
+/**
+ * enum stp_packet_type - STP packets that an STM driver sends
+ */
+enum stp_packet_type {
+ STP_PACKET_DATA = 0,
+ STP_PACKET_FLAG,
+ STP_PACKET_USER,
+ STP_PACKET_MERR,
+ STP_PACKET_GERR,
+ STP_PACKET_TRIG,
+ STP_PACKET_XSYNC,
+};
+
+/**
+ * enum stp_packet_flags - STP packet modifiers
+ */
+enum stp_packet_flags {
+ STP_PACKET_MARKED = 0x1,
+ STP_PACKET_TIMESTAMPED = 0x2,
+};
+
+struct stp_policy;
+
+struct stm_device;
+
+/**
+ * struct stm_data - STM device description and callbacks
+ * @name: device name
+ * @stm: internal structure, only used by stm class code
+ * @sw_start: first STP master available to software
+ * @sw_end: last STP master available to software
+ * @sw_nchannels: number of STP channels per master
+ * @sw_mmiosz: size of one channel's IO space, for mmap, optional
+ * @packet: callback that sends an STP packet
+ * @mmio_addr: mmap callback, optional
+ * @link: called when a new stm_source gets linked to us, optional
+ * @unlink: likewise for unlinking, again optional
+ * @set_options: set device-specific options on a channel
+ *
+ * Fill out this structure before calling stm_register_device() to create
+ * an STM device and stm_unregister_device() to destroy it. It will also be
+ * passed back to @packet(), @mmio_addr(), @link(), @unlink() and @set_options()
+ * callbacks.
+ *
+ * Normally, an STM device will have a range of masters available to software
+ * and the rest being statically assigned to various hardware trace sources.
+ * The former is defined by the the range [@sw_start..@sw_end] of the device
+ * description. That is, the lowest master that can be allocated to software
+ * writers is @sw_start and data from this writer will appear is @sw_start
+ * master in the STP stream.
+ */
+struct stm_data {
+ const char *name;
+ struct stm_device *stm;
+ unsigned int sw_start;
+ unsigned int sw_end;
+ unsigned int sw_nchannels;
+ unsigned int sw_mmiosz;
+ ssize_t (*packet)(struct stm_data *, unsigned int,
+ unsigned int, unsigned int,
+ unsigned int, unsigned int,
+ const unsigned char *);
+ phys_addr_t (*mmio_addr)(struct stm_data *, unsigned int,
+ unsigned int, unsigned int);
+ int (*link)(struct stm_data *, unsigned int,
+ unsigned int);
+ void (*unlink)(struct stm_data *, unsigned int,
+ unsigned int);
+ long (*set_options)(struct stm_data *, unsigned int,
+ unsigned int, unsigned int,
+ unsigned long);
+};
+
+int stm_register_device(struct device *parent, struct stm_data *stm_data,
+ struct module *owner);
+void stm_unregister_device(struct stm_data *stm_data);
+
+struct stm_source_device;
+
+/**
+ * struct stm_source_data - STM source device description and callbacks
+ * @name: device name, will be used for policy lookup
+ * @src: internal structure, only used by stm class code
+ * @nr_chans: number of channels to allocate
+ * @link: called when this source gets linked to an STM device
+ * @unlink: called when this source is about to get unlinked from its STM
+ *
+ * Fill in this structure before calling stm_source_register_device() to
+ * register a source device. Also pass it to unregister and write calls.
+ */
+struct stm_source_data {
+ const char *name;
+ struct stm_source_device *src;
+ unsigned int percpu;
+ unsigned int nr_chans;
+ int (*link)(struct stm_source_data *data);
+ void (*unlink)(struct stm_source_data *data);
+};
+
+int stm_source_register_device(struct device *parent,
+ struct stm_source_data *data);
+void stm_source_unregister_device(struct stm_source_data *data);
+
+int stm_source_write(struct stm_source_data *data, unsigned int chan,
+ const char *buf, size_t count);
+
+#endif /* _STM_H_ */
diff --git a/include/uapi/linux/stm.h b/include/uapi/linux/stm.h
new file mode 100644
index 0000000000000000000000000000000000000000..626a8d3f63b573204e1ad8c85d789cf3dae940f0
--- /dev/null
+++ b/include/uapi/linux/stm.h
@@ -0,0 +1,50 @@
+/*
+ * System Trace Module (STM) userspace interfaces
+ * 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 _UAPI_LINUX_STM_H
+#define _UAPI_LINUX_STM_H
+
+#include <linux/types.h>
+
+/**
+ * struct stp_policy_id - identification for the STP policy
+ * @size: size of the structure including real id[] length
+ * @master: assigned master
+ * @channel: first assigned channel
+ * @width: number of requested channels
+ * @id: identification string
+ *
+ * User must calculate the total size of the structure and put it into
+ * @size field, fill out the @id and desired @width. In return, kernel
+ * fills out @master, @channel and @width.
+ */
+struct stp_policy_id {
+ __u32 size;
+ __u16 master;
+ __u16 channel;
+ __u16 width;
+ /* padding */
+ __u16 __reserved_0;
+ __u32 __reserved_1;
+ char id[0];
+};
+
+#define STP_POLICY_ID_SET _IOWR('%', 0, struct stp_policy_id)
+#define STP_POLICY_ID_GET _IOR('%', 1, struct stp_policy_id)
+#define STP_SET_OPTIONS _IOW('%', 2, __u64)
+
+#endif /* _UAPI_LINUX_STM_H */