stm class: Introduce an abstraction for System Trace Module devices

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. This abstraction provides a unified interface for software trace sources to send their data over an STM device to a debug host. In order to do that, such a trace source needs to be assigned a pair of master/channel identifiers that all the data from this source will be tagged with. The STP decoder on the debug host side will use these master/channel tags to distinguish different trace streams from one another inside one STP stream. This abstraction provides a configfs-based policy management mechanism for dynamic allocation of these master/channel pairs based on trace source-supplied string identifier. It has the flexibility of being defined at runtime and at the same time (provided that the policy definition is aligned with the decoding end) consistency. For userspace trace sources, this abstraction provides write()-based and mmap()-based (if the underlying stm device allows this) output mechanism. For kernel-side trace sources, we provide "stm_source" device class that can be connected to an stm device at run time.

Alexander Shishkin committed 11 years ago

Commit 7bd1d401 parent 9b7696814 files · +1991 −0Browse files

Unified · Split

14 files

Documentation/ABI/testing/configfs-stp-policy +48 −0
Documentation/ABI/testing/sysfs-class-stm +14 −0
Documentation/ABI/testing/sysfs-class-stm_source +11 −0
Documentation/ioctl/ioctl-number.txt +3 −0
Documentation/trace/stm.txt +80 −0
drivers/Kconfig +2 −0
drivers/Makefile +1 −0
drivers/hwtracing/stm/Kconfig +8 −0
drivers/hwtracing/stm/Makefile +3 −0
drivers/hwtracing/stm/core.c +1029 −0
drivers/hwtracing/stm/policy.c +529 −0
drivers/hwtracing/stm/stm.h +87 −0
include/linux/stm.h +126 −0
include/uapi/linux/stm.h +50 −0

Documentation/ABI/testing/configfs-stp-policy+48−0

@@ -0,0 +1,48 @@
	1	+What: /config/stp-policy
	2	+Date: June 2015
	3	+KernelVersion: 4.3
	4	+Description:
	5	+ This group contains policies mandating Master/Channel allocation
	6	+ for software sources wishing to send trace data over an STM
	7	+ device.
	8	+
	9	+What: /config/stp-policy/<device>.<policy>
	10	+Date: June 2015
	11	+KernelVersion: 4.3
	12	+Description:
	13	+ This group is the root of a policy; its name is a concatenation
	14	+ of an stm device name to which this policy applies and an
	15	+ arbitrary string. If <device> part doesn't match an existing
	16	+ stm device, mkdir will fail with ENODEV; if that device already
	17	+ has a policy assigned to it, mkdir will fail with EBUSY.
	18	+
	19	+What: /config/stp-policy/<device>.<policy>/device
	20	+Date: June 2015
	21	+KernelVersion: 4.3
	22	+Description:
	23	+ STM device to which this policy applies, read only. Same as the
	24	+ <device> component of its parent directory.
	25	+
	26	+What: /config/stp-policy/<device>.<policy>/<node>
	27	+Date: June 2015
	28	+KernelVersion: 4.3
	29	+Description:
	30	+ Policy node is a string identifier that software clients will
	31	+ use to request a master/channel to be allocated and assigned to
	32	+ them.
	33	+
	34	+What: /config/stp-policy/<device>.<policy>/<node>/masters
	35	+Date: June 2015
	36	+KernelVersion: 4.3
	37	+Description:
	38	+ Range of masters from which to allocate for users of this node.
	39	+ Write two numbers: the first master and the last master number.
	40	+
	41	+What: /config/stp-policy/<device>.<policy>/<node>/channels
	42	+Date: June 2015
	43	+KernelVersion: 4.3
	44	+Description:
	45	+ Range of channels from which to allocate for users of this node.
	46	+ Write two numbers: the first channel and the last channel
	47	+ number.
	48	+

Documentation/ABI/testing/sysfs-class-stm+14−0

@@ -0,0 +1,14 @@
	1	+What: /sys/class/stm/<stm>/masters
	2	+Date: June 2015
	3	+KernelVersion: 4.3
	4	+Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
	5	+Description:
	6	+ Shows first and last available to software master numbers on
	7	+ this STM device.
	8	+
	9	+What: /sys/class/stm/<stm>/channels
	10	+Date: June 2015
	11	+KernelVersion: 4.3
	12	+Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
	13	+Description:
	14	+ Shows the number of channels per master on this STM device.

Documentation/ABI/testing/sysfs-class-stm_source+11−0

@@ -0,0 +1,11 @@
	1	+What: /sys/class/stm_source/<stm_source>/stm_source_link
	2	+Date: June 2015
	3	+KernelVersion: 4.3
	4	+Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
	5	+Description:
	6	+ stm_source device linkage to stm device, where its tracing data
	7	+ is directed. Reads return an existing connection or "<none>" if
	8	+ this stm_source is not connected to any stm device yet.
	9	+ Write an existing (registered) stm device's name here to
	10	+ connect that device. If a device is already connected to this
	11	+ stm_source, it will first be disconnected.

Documentation/ioctl/ioctl-number.txt+3−0

@@ -81,6 +81,9 @@ Code Seq#(hex) Include File Comments · 80 unmodified lines
81	81	0x22 all scsi/sg.h
82	82	'#' 00-3F IEEE 1394 Subsystem Block for the entire subsystem
83	83	'$' 00-0F linux/perf_counter.h, linux/perf_event.h
	84	+'%' 00-0F include/uapi/linux/stm.h
	85	+ System Trace Module subsystem
	86	+ <mailto:alexander.shishkin@linux.intel.com>
84	87	'&' 00-07 drivers/firewire/nosy-user.h
85	88	'1' 00-1F <linux/timepps.h> PPS kit from Ulrich Windl
86	89	<ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>

Documentation/trace/stm.txt+80−0

@@ -0,0 +1,80 @@
	1	+System Trace Module
	2	+===================
	3	+
	4	+System Trace Module (STM) is a device described in MIPI STP specs as
	5	+STP trace stream generator. STP (System Trace Protocol) is a trace
	6	+protocol multiplexing data from multiple trace sources, each one of
	7	+which is assigned a unique pair of master and channel. While some of
	8	+these masters and channels are statically allocated to certain
	9	+hardware trace sources, others are available to software. Software
	10	+trace sources are usually free to pick for themselves any
	11	+master/channel combination from this pool.
	12	+
	13	+On the receiving end of this STP stream (the decoder side), trace
	14	+sources can only be identified by master/channel combination, so in
	15	+order for the decoder to be able to make sense of the trace that
	16	+involves multiple trace sources, it needs to be able to map those
	17	+master/channel pairs to the trace sources that it understands.
	18	+
	19	+For instance, it is helpful to know that syslog messages come on
	20	+master 7 channel 15, while arbitrary user applications can use masters
	21	+48 to 63 and channels 0 to 127.
	22	+
	23	+To solve this mapping problem, stm class provides a policy management
	24	+mechanism via configfs, that allows defining rules that map string
	25	+identifiers to ranges of masters and channels. If these rules (policy)
	26	+are consistent with what decoder expects, it will be able to properly
	27	+process the trace data.
	28	+
	29	+This policy is a tree structure containing rules (policy_node) that
	30	+have a name (string identifier) and a range of masters and channels
	31	+associated with it, located in "stp-policy" subsystem directory in
	32	+configfs. The topmost directory's name (the policy) is formatted as
	33	+the STM device name to which this policy applies and and arbitrary
	34	+string identifier separated by a stop. From the examle above, a rule
	35	+may look like this:
	36	+
	37	+$ ls /config/stp-policy/dummy_stm.my-policy/user
	38	+channels masters
	39	+$ cat /config/stp-policy/dummy_stm.my-policy/user/masters
	40	+48 63
	41	+$ cat /config/stp-policy/dummy_stm.my-policy/user/channels
	42	+0 127
	43	+
	44	+which means that the master allocation pool for this rule consists of
	45	+masters 48 through 63 and channel allocation pool has channels 0
	46	+through 127 in it. Now, any producer (trace source) identifying itself
	47	+with "user" identification string will be allocated a master and
	48	+channel from within these ranges.
	49	+
	50	+These rules can be nested, for example, one can define a rule "dummy"
	51	+under "user" directory from the example above and this new rule will
	52	+be used for trace sources with the id string of "user/dummy".
	53	+
	54	+Trace sources have to open the stm class device's node and write their
	55	+trace data into its file descriptor. In order to identify themselves
	56	+to the policy, they need to do a STP_POLICY_ID_SET ioctl on this file
	57	+descriptor providing their id string. Otherwise, they will be
	58	+automatically allocated a master/channel pair upon first write to this
	59	+file descriptor according to the "default" rule of the policy, if such
	60	+exists.
	61	+
	62	+Some STM devices may allow direct mapping of the channel mmio regions
	63	+to userspace for zero-copy writing. One mappable page (in terms of
	64	+mmu) will usually contain multiple channels' mmios, so the user will
	65	+need to allocate that many channels to themselves (via the
	66	+aforementioned ioctl() call) to be able to do this. That is, if your
	67	+stm device's channel mmio region is 64 bytes and hardware page size is
	68	+4096 bytes, after a successful STP_POLICY_ID_SET ioctl() call with
	69	+width==64, you should be able to mmap() one page on this file
	70	+descriptor and obtain direct access to an mmio region for 64 channels.
	71	+
	72	+For kernel-based trace sources, there is "stm_source" device
	73	+class. Devices of this class can be connected and disconnected to/from
	74	+stm devices at runtime via a sysfs attribute.
	75	+
	76	+Examples of STM devices are Intel(R) Trace Hub [1] and Coresight STM
	77	+[2].
	78	+
	79	+[1] https://software.intel.com/sites/default/files/managed/d3/3c/intel-th-developer-manual.pdf
	80	+[2] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0444b/index.html

drivers/Kconfig+2−0

@@ -188,4 +188,6 @@ source "drivers/nvdimm/Kconfig" · 187 unmodified lines
188	188
189	189	source "drivers/nvmem/Kconfig"
190	190
	191	+source "drivers/hwtracing/stm/Kconfig"
	192	+
191	193	endmenu

drivers/Makefile+1−0

@@ -165,5 +165,6 @@ obj-$(CONFIG_PERF_EVENTS) += perf/ · 164 unmodified lines
165	165	obj-$(CONFIG_RAS) += ras/
166	166	obj-$(CONFIG_THUNDERBOLT) += thunderbolt/
167	167	obj-$(CONFIG_CORESIGHT) += hwtracing/coresight/
	168	+obj-$(CONFIG_STM) += hwtracing/stm/
168	169	obj-$(CONFIG_ANDROID) += android/
169	170	obj-$(CONFIG_NVMEM) += nvmem/

drivers/hwtracing/stm/Kconfig+8−0

@@ -0,0 +1,8 @@
	1	+config STM
	2	+ tristate "System Trace Module devices"
	3	+ help
	4	+ A System Trace Module (STM) is a device exporting data in System
	5	+ Trace Protocol (STP) format as defined by MIPI STP standards.
	6	+ Examples of such devices are Intel(R) Trace Hub and Coresight STM.
	7	+
	8	+ Say Y here to enable System Trace Module device support.

drivers/hwtracing/stm/Makefile+3−0

@@ -0,0 +1,3 @@
	1	+obj-$(CONFIG_STM) += stm_core.o
	2	+
	3	+stm_core-y := core.o policy.o

drivers/hwtracing/stm/core.c+1029−0

@@ -0,0 +1,1029 @@
	1	+/*
	2	+ * System Trace Module (STM) infrastructure
	3	+ * Copyright (c) 2014, Intel Corporation.
	4	+ *
	5	+ * This program is free software; you can redistribute it and/or modify it
	6	+ * under the terms and conditions of the GNU General Public License,
	7	+ * version 2, as published by the Free Software Foundation.
	8	+ *
	9	+ * This program is distributed in the hope it will be useful, but WITHOUT
	10	+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	12	+ * more details.
	13	+ *
	14	+ * STM class implements generic infrastructure for System Trace Module devices
	15	+ * as defined in MIPI STPv2 specification.
	16	+ */
	17	+
	18	+#include <linux/uaccess.h>
	19	+#include <linux/kernel.h>
	20	+#include <linux/module.h>
	21	+#include <linux/device.h>
	22	+#include <linux/compat.h>
	23	+#include <linux/kdev_t.h>
	24	+#include <linux/srcu.h>
	25	+#include <linux/slab.h>
	26	+#include <linux/stm.h>
	27	+#include <linux/fs.h>
	28	+#include <linux/mm.h>
	29	+#include "stm.h"
	30	+
	31	+#include <uapi/linux/stm.h>
	32	+
	33	+static unsigned int stm_core_up;
	34	+
	35	+/*
	36	+ * The SRCU here makes sure that STM device doesn't disappear from under a
	37	+ * stm_source_write() caller, which may want to have as little overhead as
	38	+ * possible.
	39	+ */
	40	+static struct srcu_struct stm_source_srcu;
	41	+
	42	+static ssize_t masters_show(struct device *dev,
	43	+ struct device_attribute *attr,
	44	+ char *buf)
	45	+{
	46	+ struct stm_device *stm = to_stm_device(dev);
	47	+ int ret;
	48	+
	49	+ ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end);
	50	+
	51	+ return ret;
	52	+}
	53	+
	54	+static DEVICE_ATTR_RO(masters);
	55	+
	56	+static ssize_t channels_show(struct device *dev,
	57	+ struct device_attribute *attr,
	58	+ char *buf)
	59	+{
	60	+ struct stm_device *stm = to_stm_device(dev);
	61	+ int ret;
	62	+
	63	+ ret = sprintf(buf, "%u\n", stm->data->sw_nchannels);
	64	+
	65	+ return ret;
	66	+}
	67	+
	68	+static DEVICE_ATTR_RO(channels);
	69	+
	70	+static struct attribute *stm_attrs[] = {
	71	+ &dev_attr_masters.attr,
	72	+ &dev_attr_channels.attr,
	73	+ NULL,
	74	+};
	75	+
	76	+ATTRIBUTE_GROUPS(stm);
	77	+
	78	+static struct class stm_class = {
	79	+ .name = "stm",
	80	+ .dev_groups = stm_groups,
	81	+};
	82	+
	83	+static int stm_dev_match(struct device dev, const void data)
	84	+{
	85	+ const char *name = data;
	86	+
	87	+ return sysfs_streq(name, dev_name(dev));
	88	+}
	89	+
	90	+/**
	91	+ * stm_find_device() - find stm device by name
	92	+ * @buf: character buffer containing the name
	93	+ *
	94	+ * This is called when either policy gets assigned to an stm device or an
	95	+ * stm_source device gets linked to an stm device.
	96	+ *
	97	+ * This grabs device's reference (get_device()) and module reference, both
	98	+ * of which the calling path needs to make sure to drop with stm_put_device().
	99	+ *
	100	+ * Return: stm device pointer or null if lookup failed.
	101	+ */
	102	+struct stm_device stm_find_device(const char buf)
	103	+{
	104	+ struct stm_device *stm;
	105	+ struct device *dev;
	106	+
	107	+ if (!stm_core_up)
	108	+ return NULL;
	109	+
	110	+ dev = class_find_device(&stm_class, NULL, buf, stm_dev_match);
	111	+ if (!dev)
	112	+ return NULL;
	113	+
	114	+ stm = to_stm_device(dev);
	115	+ if (!try_module_get(stm->owner)) {
	116	+ put_device(dev);
	117	+ return NULL;
	118	+ }
	119	+
	120	+ return stm;
	121	+}
	122	+
	123	+/**
	124	+ * stm_put_device() - drop references on the stm device
	125	+ * @stm: stm device, previously acquired by stm_find_device()
	126	+ *
	127	+ * This drops the module reference and device reference taken by
	128	+ * stm_find_device().
	129	+ */
	130	+void stm_put_device(struct stm_device *stm)
	131	+{
	132	+ module_put(stm->owner);
	133	+ put_device(&stm->dev);
	134	+}
	135	+
	136	+/*
	137	+ * Internally we only care about software-writable masters here, that is the
	138	+ * ones in the range [stm_data->sw_start..stm_data..sw_end], however we need
	139	+ * original master numbers to be visible externally, since they are the ones
	140	+ * that will appear in the STP stream. Thus, the internal bookkeeping uses
	141	+ * $master - stm_data->sw_start to reference master descriptors and such.
	142	+ */
	143	+
	144	+#define __stm_master(_s, _m) \
	145	+ ((_s)->masters[(_m) - (_s)->data->sw_start])
	146	+
	147	+static inline struct stp_master *
	148	+stm_master(struct stm_device *stm, unsigned int idx)
	149	+{
	150	+ if (idx < stm->data->sw_start \|\| idx > stm->data->sw_end)
	151	+ return NULL;
	152	+
	153	+ return __stm_master(stm, idx);
	154	+}
	155	+
	156	+static int stp_master_alloc(struct stm_device *stm, unsigned int idx)
	157	+{
	158	+ struct stp_master *master;
	159	+ size_t size;
	160	+
	161	+ size = ALIGN(stm->data->sw_nchannels, 8) / 8;
	162	+ size += sizeof(struct stp_master);
	163	+ master = kzalloc(size, GFP_ATOMIC);
	164	+ if (!master)
	165	+ return -ENOMEM;
	166	+
	167	+ master->nr_free = stm->data->sw_nchannels;
	168	+ __stm_master(stm, idx) = master;
	169	+
	170	+ return 0;
	171	+}
	172	+
	173	+static void stp_master_free(struct stm_device *stm, unsigned int idx)
	174	+{
	175	+ struct stp_master *master = stm_master(stm, idx);
	176	+
	177	+ if (!master)
	178	+ return;
	179	+
	180	+ __stm_master(stm, idx) = NULL;
	181	+ kfree(master);
	182	+}
	183	+
	184	+static void stm_output_claim(struct stm_device stm, struct stm_output output)
	185	+{
	186	+ struct stp_master *master = stm_master(stm, output->master);
	187	+
	188	+ if (WARN_ON_ONCE(master->nr_free < output->nr_chans))
	189	+ return;
	190	+
	191	+ bitmap_allocate_region(&master->chan_map[0], output->channel,
	192	+ ilog2(output->nr_chans));
	193	+
	194	+ master->nr_free -= output->nr_chans;
	195	+}
	196	+
	197	+static void
	198	+stm_output_disclaim(struct stm_device stm, struct stm_output output)
	199	+{
	200	+ struct stp_master *master = stm_master(stm, output->master);
	201	+
	202	+ bitmap_release_region(&master->chan_map[0], output->channel,
	203	+ ilog2(output->nr_chans));
	204	+
	205	+ output->nr_chans = 0;
	206	+ master->nr_free += output->nr_chans;
	207	+}
	208	+
	209	+/*
	210	+ * This is like bitmap_find_free_region(), except it can ignore @start bits
	211	+ * at the beginning.
	212	+ */
	213	+static int find_free_channels(unsigned long *bitmap, unsigned int start,
	214	+ unsigned int end, unsigned int width)
	215	+{
	216	+ unsigned int pos;
	217	+ int i;
	218	+
	219	+ for (pos = start; pos < end + 1; pos = ALIGN(pos, width)) {
	220	+ pos = find_next_zero_bit(bitmap, end + 1, pos);
	221	+ if (pos + width > end + 1)
	222	+ break;
	223	+
	224	+ if (pos & (width - 1))
	225	+ continue;
	226	+
	227	+ for (i = 1; i < width && !test_bit(pos + i, bitmap); i++)
	228	+ ;
	229	+ if (i == width)
	230	+ return pos;
	231	+ }
	232	+
	233	+ return -1;
	234	+}
	235	+
	236	+static unsigned int
	237	+stm_find_master_chan(struct stm_device *stm, unsigned int width,
	238	+ unsigned int *mstart, unsigned int mend,
	239	+ unsigned int *cstart, unsigned int cend)
	240	+{
	241	+ struct stp_master *master;
	242	+ unsigned int midx;
	243	+ int pos, err;
	244	+
	245	+ for (midx = *mstart; midx <= mend; midx++) {
	246	+ if (!stm_master(stm, midx)) {
	247	+ err = stp_master_alloc(stm, midx);
	248	+ if (err)
	249	+ return err;
	250	+ }
	251	+
	252	+ master = stm_master(stm, midx);
	253	+
	254	+ if (!master->nr_free)
	255	+ continue;
	256	+
	257	+ pos = find_free_channels(master->chan_map, *cstart, cend,
	258	+ width);
	259	+ if (pos < 0)
	260	+ continue;
	261	+
	262	+ *mstart = midx;
	263	+ *cstart = pos;
	264	+ return 0;
	265	+ }
	266	+
	267	+ return -ENOSPC;
	268	+}
	269	+
	270	+static int stm_output_assign(struct stm_device *stm, unsigned int width,
	271	+ struct stp_policy_node *policy_node,
	272	+ struct stm_output *output)
	273	+{
	274	+ unsigned int midx, cidx, mend, cend;
	275	+ int ret = -EINVAL;
	276	+
	277	+ if (width > stm->data->sw_nchannels)
	278	+ return -EINVAL;
	279	+
	280	+ if (policy_node) {
	281	+ stp_policy_node_get_ranges(policy_node,
	282	+ &midx, &mend, &cidx, &cend);
	283	+ } else {
	284	+ midx = stm->data->sw_start;
	285	+ cidx = 0;
	286	+ mend = stm->data->sw_end;
	287	+ cend = stm->data->sw_nchannels - 1;
	288	+ }
	289	+
	290	+ spin_lock(&stm->mc_lock);
	291	+ /* output is already assigned -- shouldn't happen */
	292	+ if (WARN_ON_ONCE(output->nr_chans))
	293	+ goto unlock;
	294	+
	295	+ ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend);
	296	+ if (ret)
	297	+ goto unlock;
	298	+
	299	+ output->master = midx;
	300	+ output->channel = cidx;
	301	+ output->nr_chans = width;
	302	+ stm_output_claim(stm, output);
	303	+ dev_dbg(&stm->dev, "assigned %u:%u (+%u)\n", midx, cidx, width);
	304	+
	305	+ ret = 0;
	306	+unlock:
	307	+ spin_unlock(&stm->mc_lock);
	308	+
	309	+ return ret;
	310	+}
	311	+
	312	+static void stm_output_free(struct stm_device stm, struct stm_output output)
	313	+{
	314	+ spin_lock(&stm->mc_lock);
	315	+ if (output->nr_chans)
	316	+ stm_output_disclaim(stm, output);
	317	+ spin_unlock(&stm->mc_lock);
	318	+}
	319	+
	320	+static int major_match(struct device dev, const void data)
	321	+{
	322	+ unsigned int major = (unsigned int )data;
	323	+
	324	+ return MAJOR(dev->devt) == major;
	325	+}
	326	+
	327	+static int stm_char_open(struct inode inode, struct file file)
	328	+{
	329	+ struct stm_file *stmf;
	330	+ struct device *dev;
	331	+ unsigned int major = imajor(inode);
	332	+ int err = -ENODEV;
	333	+
	334	+ dev = class_find_device(&stm_class, NULL, &major, major_match);
	335	+ if (!dev)
	336	+ return -ENODEV;
	337	+
	338	+ stmf = kzalloc(sizeof(*stmf), GFP_KERNEL);
	339	+ if (!stmf)
	340	+ return -ENOMEM;
	341	+
	342	+ stmf->stm = to_stm_device(dev);
	343	+
	344	+ if (!try_module_get(stmf->stm->owner))
	345	+ goto err_free;
	346	+
	347	+ file->private_data = stmf;
	348	+
	349	+ return nonseekable_open(inode, file);
	350	+
	351	+err_free:
	352	+ kfree(stmf);
	353	+
	354	+ return err;
	355	+}
	356	+
	357	+static int stm_char_release(struct inode inode, struct file file)
	358	+{
	359	+ struct stm_file *stmf = file->private_data;
	360	+
	361	+ stm_output_free(stmf->stm, &stmf->output);
	362	+ stm_put_device(stmf->stm);
	363	+ kfree(stmf);
	364	+
	365	+ return 0;
	366	+}
	367	+
	368	+static int stm_file_assign(struct stm_file stmf, char id, unsigned int width)
	369	+{
	370	+ struct stm_device *stm = stmf->stm;
	371	+ int ret;
	372	+
	373	+ stmf->policy_node = stp_policy_node_lookup(stm, id);
	374	+
	375	+ ret = stm_output_assign(stm, width, stmf->policy_node, &stmf->output);
	376	+
	377	+ if (stmf->policy_node)
	378	+ stp_policy_node_put(stmf->policy_node);
	379	+
	380	+ return ret;
	381	+}
	382	+
	383	+static void stm_write(struct stm_data *data, unsigned int master,
	384	+ unsigned int channel, const char *buf, size_t count)
	385	+{
	386	+ unsigned int flags = STP_PACKET_TIMESTAMPED;
	387	+ const unsigned char *p = buf, nil = 0;
	388	+ size_t pos;
	389	+ ssize_t sz;
	390	+
	391	+ for (pos = 0, p = buf; count > pos; pos += sz, p += sz) {
	392	+ sz = min_t(unsigned int, count - pos, 8);
	393	+ sz = data->packet(data, master, channel, STP_PACKET_DATA, flags,
	394	+ sz, p);
	395	+ flags = 0;
	396	+ }
	397	+
	398	+ data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil);
	399	+}
	400	+
	401	+static ssize_t stm_char_write(struct file file, const char __user buf,
	402	+ size_t count, loff_t *ppos)
	403	+{
	404	+ struct stm_file *stmf = file->private_data;
	405	+ struct stm_device *stm = stmf->stm;
	406	+ char *kbuf;
	407	+ int err;
	408	+
	409	+ /*
	410	+ * if no m/c have been assigned to this writer up to this
	411	+ * point, use "default" policy entry
	412	+ */
	413	+ if (!stmf->output.nr_chans) {
	414	+ err = stm_file_assign(stmf, "default", 1);
	415	+ /*
	416	+ * EBUSY means that somebody else just assigned this
	417	+ * output, which is just fine for write()
	418	+ */
	419	+ if (err && err != -EBUSY)
	420	+ return err;
	421	+ }
	422	+
	423	+ kbuf = kmalloc(count + 1, GFP_KERNEL);
	424	+ if (!kbuf)
	425	+ return -ENOMEM;
	426	+
	427	+ err = copy_from_user(kbuf, buf, count);
	428	+ if (err) {
	429	+ kfree(kbuf);
	430	+ return -EFAULT;
	431	+ }
	432	+
	433	+ stm_write(stm->data, stmf->output.master, stmf->output.channel, kbuf,
	434	+ count);
	435	+
	436	+ kfree(kbuf);
	437	+
	438	+ return count;
	439	+}
	440	+
	441	+static int stm_char_mmap(struct file file, struct vm_area_struct vma)
	442	+{
	443	+ struct stm_file *stmf = file->private_data;
	444	+ struct stm_device *stm = stmf->stm;
	445	+ unsigned long size, phys;
	446	+
	447	+ if (!stm->data->mmio_addr)
	448	+ return -EOPNOTSUPP;
	449	+
	450	+ if (vma->vm_pgoff)
	451	+ return -EINVAL;
	452	+
	453	+ size = vma->vm_end - vma->vm_start;
	454	+
	455	+ if (stmf->output.nr_chans * stm->data->sw_mmiosz != size)
	456	+ return -EINVAL;
	457	+
	458	+ phys = stm->data->mmio_addr(stm->data, stmf->output.master,
	459	+ stmf->output.channel,
	460	+ stmf->output.nr_chans);
	461	+
	462	+ if (!phys)
	463	+ return -EINVAL;
	464	+
	465	+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	466	+ vma->vm_flags \|= VM_IO \| VM_DONTEXPAND \| VM_DONTDUMP;
	467	+ vm_iomap_memory(vma, phys, size);
	468	+
	469	+ return 0;
	470	+}
	471	+
	472	+static int stm_char_policy_set_ioctl(struct stm_file stmf, void __user arg)
	473	+{
	474	+ struct stm_device *stm = stmf->stm;
	475	+ struct stp_policy_id *id;
	476	+ int ret = -EINVAL;
	477	+ u32 size;
	478	+
	479	+ if (stmf->output.nr_chans)
	480	+ return -EBUSY;
	481	+
	482	+ if (copy_from_user(&size, arg, sizeof(size)))
	483	+ return -EFAULT;
	484	+
	485	+ if (size >= PATH_MAX + sizeof(*id))
	486	+ return -EINVAL;
	487	+
	488	+ /*
	489	+ * size + 1 to make sure the .id string at the bottom is terminated,
	490	+ * which is also why memdup_user() is not useful here
	491	+ */
	492	+ id = kzalloc(size + 1, GFP_KERNEL);
	493	+ if (!id)
	494	+ return -ENOMEM;
	495	+
	496	+ if (copy_from_user(id, arg, size)) {
	497	+ ret = -EFAULT;
	498	+ goto err_free;
	499	+ }
	500	+
	501	+ if (id->__reserved_0 \|\| id->__reserved_1)
	502	+ goto err_free;
	503	+
	504	+ if (id->width < 1 \|\|
	505	+ id->width > PAGE_SIZE / stm->data->sw_mmiosz)
	506	+ goto err_free;
	507	+
	508	+ ret = stm_file_assign(stmf, id->id, id->width);
	509	+ if (ret)
	510	+ goto err_free;
	511	+
	512	+ ret = 0;
	513	+
	514	+ if (stm->data->link)
	515	+ ret = stm->data->link(stm->data, stmf->output.master,
	516	+ stmf->output.channel);
	517	+
	518	+ if (ret) {
	519	+ stm_output_free(stmf->stm, &stmf->output);
	520	+ stm_put_device(stmf->stm);
	521	+ }
	522	+
	523	+err_free:
	524	+ kfree(id);
	525	+
	526	+ return ret;
	527	+}
	528	+
	529	+static int stm_char_policy_get_ioctl(struct stm_file stmf, void __user arg)
	530	+{
	531	+ struct stp_policy_id id = {
	532	+ .size = sizeof(id),
	533	+ .master = stmf->output.master,
	534	+ .channel = stmf->output.channel,
	535	+ .width = stmf->output.nr_chans,
	536	+ .__reserved_0 = 0,
	537	+ .__reserved_1 = 0,
	538	+ };
	539	+
	540	+ return copy_to_user(arg, &id, id.size) ? -EFAULT : 0;
	541	+}
	542	+
	543	+static long
	544	+stm_char_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	545	+{
	546	+ struct stm_file *stmf = file->private_data;
	547	+ struct stm_data *stm_data = stmf->stm->data;
	548	+ int err = -ENOTTY;
	549	+ u64 options;
	550	+
	551	+ switch (cmd) {
	552	+ case STP_POLICY_ID_SET:
	553	+ err = stm_char_policy_set_ioctl(stmf, (void __user *)arg);
	554	+ if (err)
	555	+ return err;
	556	+
	557	+ return stm_char_policy_get_ioctl(stmf, (void __user *)arg);
	558	+
	559	+ case STP_POLICY_ID_GET:
	560	+ return stm_char_policy_get_ioctl(stmf, (void __user *)arg);
	561	+
	562	+ case STP_SET_OPTIONS:
	563	+ if (copy_from_user(&options, (u64 __user *)arg, sizeof(u64)))
	564	+ return -EFAULT;
	565	+
	566	+ if (stm_data->set_options)
	567	+ err = stm_data->set_options(stm_data,
	568	+ stmf->output.master,
	569	+ stmf->output.channel,
	570	+ stmf->output.nr_chans,
	571	+ options);
	572	+
	573	+ break;
	574	+ default:
	575	+ break;
	576	+ }
	577	+
	578	+ return err;
	579	+}
	580	+
	581	+#ifdef CONFIG_COMPAT
	582	+static long
	583	+stm_char_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	584	+{
	585	+ return stm_char_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
	586	+}
	587	+#else
	588	+#define stm_char_compat_ioctl NULL
	589	+#endif
	590	+
	591	+static const struct file_operations stm_fops = {
	592	+ .open = stm_char_open,
	593	+ .release = stm_char_release,
	594	+ .write = stm_char_write,
	595	+ .mmap = stm_char_mmap,
	596	+ .unlocked_ioctl = stm_char_ioctl,
	597	+ .compat_ioctl = stm_char_compat_ioctl,
	598	+ .llseek = no_llseek,
	599	+};
	600	+
	601	+static void stm_device_release(struct device *dev)
	602	+{
	603	+ struct stm_device *stm = to_stm_device(dev);
	604	+
	605	+ kfree(stm);
	606	+}
	607	+
	608	+int stm_register_device(struct device parent, struct stm_data stm_data,
	609	+ struct module *owner)
	610	+{
	611	+ struct stm_device *stm;
	612	+ unsigned int nmasters;
	613	+ int err = -ENOMEM;
	614	+
	615	+ if (!stm_core_up)
	616	+ return -EPROBE_DEFER;
	617	+
	618	+ if (!stm_data->packet \|\| !stm_data->sw_nchannels)
	619	+ return -EINVAL;
	620	+
	621	+ nmasters = stm_data->sw_end - stm_data->sw_start;
	622	+ stm = kzalloc(sizeof(stm) + nmasters sizeof(void *), GFP_KERNEL);
	623	+ if (!stm)
	624	+ return -ENOMEM;
	625	+
	626	+ stm->major = register_chrdev(0, stm_data->name, &stm_fops);
	627	+ if (stm->major < 0)
	628	+ goto err_free;
	629	+
	630	+ device_initialize(&stm->dev);
	631	+ stm->dev.devt = MKDEV(stm->major, 0);
	632	+ stm->dev.class = &stm_class;
	633	+ stm->dev.parent = parent;
	634	+ stm->dev.release = stm_device_release;
	635	+
	636	+ err = kobject_set_name(&stm->dev.kobj, "%s", stm_data->name);
	637	+ if (err)
	638	+ goto err_device;
	639	+
	640	+ err = device_add(&stm->dev);
	641	+ if (err)
	642	+ goto err_device;
	643	+
	644	+ spin_lock_init(&stm->link_lock);
	645	+ INIT_LIST_HEAD(&stm->link_list);
	646	+
	647	+ spin_lock_init(&stm->mc_lock);
	648	+ mutex_init(&stm->policy_mutex);
	649	+ stm->sw_nmasters = nmasters;
	650	+ stm->owner = owner;
	651	+ stm->data = stm_data;
	652	+ stm_data->stm = stm;
	653	+
	654	+ return 0;
	655	+
	656	+err_device:
	657	+ put_device(&stm->dev);
	658	+err_free:
	659	+ kfree(stm);
	660	+
	661	+ return err;
	662	+}
	663	+EXPORT_SYMBOL_GPL(stm_register_device);
	664	+
	665	+static void __stm_source_link_drop(struct stm_source_device *src,
	666	+ struct stm_device *stm);
	667	+
	668	+void stm_unregister_device(struct stm_data *stm_data)
	669	+{
	670	+ struct stm_device *stm = stm_data->stm;
	671	+ struct stm_source_device src, iter;
	672	+ int i;
	673	+
	674	+ spin_lock(&stm->link_lock);
	675	+ list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) {
	676	+ __stm_source_link_drop(src, stm);
	677	+ }
	678	+ spin_unlock(&stm->link_lock);
	679	+
	680	+ synchronize_srcu(&stm_source_srcu);
	681	+
	682	+ unregister_chrdev(stm->major, stm_data->name);
	683	+
	684	+ mutex_lock(&stm->policy_mutex);
	685	+ if (stm->policy)
	686	+ stp_policy_unbind(stm->policy);
	687	+ mutex_unlock(&stm->policy_mutex);
	688	+
	689	+ for (i = 0; i < stm->sw_nmasters; i++)
	690	+ stp_master_free(stm, i);
	691	+
	692	+ device_unregister(&stm->dev);
	693	+ stm_data->stm = NULL;
	694	+}
	695	+EXPORT_SYMBOL_GPL(stm_unregister_device);
	696	+
	697	+/**
	698	+ * stm_source_link_add() - connect an stm_source device to an stm device
	699	+ * @src: stm_source device
	700	+ * @stm: stm device
	701	+ *
	702	+ * This function establishes a link from stm_source to an stm device so that
	703	+ * the former can send out trace data to the latter.
	704	+ *
	705	+ * Return: 0 on success, -errno otherwise.
	706	+ */
	707	+static int stm_source_link_add(struct stm_source_device *src,
	708	+ struct stm_device *stm)
	709	+{
	710	+ char *id;
	711	+ int err;
	712	+
	713	+ spin_lock(&stm->link_lock);
	714	+ spin_lock(&src->link_lock);
	715	+
	716	+ /* src->link is dereferenced under stm_source_srcu but not the list */
	717	+ rcu_assign_pointer(src->link, stm);
	718	+ list_add_tail(&src->link_entry, &stm->link_list);
	719	+
	720	+ spin_unlock(&src->link_lock);
	721	+ spin_unlock(&stm->link_lock);
	722	+
	723	+ id = kstrdup(src->data->name, GFP_KERNEL);
	724	+ if (id) {
	725	+ src->policy_node =
	726	+ stp_policy_node_lookup(stm, id);
	727	+
	728	+ kfree(id);
	729	+ }
	730	+
	731	+ err = stm_output_assign(stm, src->data->nr_chans,
	732	+ src->policy_node, &src->output);
	733	+
	734	+ if (src->policy_node)
	735	+ stp_policy_node_put(src->policy_node);
	736	+
	737	+ if (err)
	738	+ goto fail_detach;
	739	+
	740	+ /* this is to notify the STM device that a new link has been made */
	741	+ if (stm->data->link)
	742	+ err = stm->data->link(stm->data, src->output.master,
	743	+ src->output.channel);
	744	+
	745	+ if (err)
	746	+ goto fail_free_output;
	747	+
	748	+ /* this is to let the source carry out all necessary preparations */
	749	+ if (src->data->link)
	750	+ src->data->link(src->data);
	751	+
	752	+ return 0;
	753	+
	754	+fail_free_output:
	755	+ stm_output_free(stm, &src->output);
	756	+ stm_put_device(stm);
	757	+
	758	+fail_detach:
	759	+ spin_lock(&stm->link_lock);
	760	+ spin_lock(&src->link_lock);
	761	+
	762	+ rcu_assign_pointer(src->link, NULL);
	763	+ list_del_init(&src->link_entry);
	764	+
	765	+ spin_unlock(&src->link_lock);
	766	+ spin_unlock(&stm->link_lock);
	767	+
	768	+ return err;
	769	+}
	770	+
	771	+/**
	772	+ * __stm_source_link_drop() - detach stm_source from an stm device
	773	+ * @src: stm_source device
	774	+ * @stm: stm device
	775	+ *
	776	+ * If @stm is @src::link, disconnect them from one another and put the
	777	+ * reference on the @stm device.
	778	+ *
	779	+ * Caller must hold stm::link_lock.
	780	+ */
	781	+static void __stm_source_link_drop(struct stm_source_device *src,
	782	+ struct stm_device *stm)
	783	+{
	784	+ spin_lock(&src->link_lock);
	785	+ if (WARN_ON_ONCE(src->link != stm)) {
	786	+ spin_unlock(&src->link_lock);
	787	+ return;
	788	+ }
	789	+
	790	+ stm_output_free(src->link, &src->output);
	791	+ /* caller must hold stm::link_lock */
	792	+ list_del_init(&src->link_entry);
	793	+ /* matches stm_find_device() from stm_source_link_store() */
	794	+ stm_put_device(src->link);
	795	+ rcu_assign_pointer(src->link, NULL);
	796	+
	797	+ spin_unlock(&src->link_lock);
	798	+}
	799	+
	800	+/**
	801	+ * stm_source_link_drop() - detach stm_source from its stm device
	802	+ * @src: stm_source device
	803	+ *
	804	+ * Unlinking means disconnecting from source's STM device; after this
	805	+ * writes will be unsuccessful until it is linked to a new STM device.
	806	+ *
	807	+ * This will happen on "stm_source_link" sysfs attribute write to undo
	808	+ * the existing link (if any), or on linked STM device's de-registration.
	809	+ */
	810	+static void stm_source_link_drop(struct stm_source_device *src)
	811	+{
	812	+ struct stm_device *stm;
	813	+ int idx;
	814	+
	815	+ idx = srcu_read_lock(&stm_source_srcu);
	816	+ stm = srcu_dereference(src->link, &stm_source_srcu);
	817	+
	818	+ if (stm) {
	819	+ if (src->data->unlink)
	820	+ src->data->unlink(src->data);
	821	+
	822	+ spin_lock(&stm->link_lock);
	823	+ __stm_source_link_drop(src, stm);
	824	+ spin_unlock(&stm->link_lock);
	825	+ }
	826	+
	827	+ srcu_read_unlock(&stm_source_srcu, idx);
	828	+}
	829	+
	830	+static ssize_t stm_source_link_show(struct device *dev,
	831	+ struct device_attribute *attr,
	832	+ char *buf)
	833	+{
	834	+ struct stm_source_device *src = to_stm_source_device(dev);
	835	+ struct stm_device *stm;
	836	+ int idx, ret;
	837	+
	838	+ idx = srcu_read_lock(&stm_source_srcu);
	839	+ stm = srcu_dereference(src->link, &stm_source_srcu);
	840	+ ret = sprintf(buf, "%s\n",
	841	+ stm ? dev_name(&stm->dev) : "<none>");
	842	+ srcu_read_unlock(&stm_source_srcu, idx);
	843	+
	844	+ return ret;
	845	+}
	846	+
	847	+static ssize_t stm_source_link_store(struct device *dev,
	848	+ struct device_attribute *attr,
	849	+ const char *buf, size_t count)
	850	+{
	851	+ struct stm_source_device *src = to_stm_source_device(dev);
	852	+ struct stm_device *link;
	853	+ int err;
	854	+
	855	+ stm_source_link_drop(src);
	856	+
	857	+ link = stm_find_device(buf);
	858	+ if (!link)
	859	+ return -EINVAL;
	860	+
	861	+ err = stm_source_link_add(src, link);
	862	+ if (err)
	863	+ stm_put_device(link);
	864	+
	865	+ return err ? : count;
	866	+}
	867	+
	868	+static DEVICE_ATTR_RW(stm_source_link);
	869	+
	870	+static struct attribute *stm_source_attrs[] = {
	871	+ &dev_attr_stm_source_link.attr,
	872	+ NULL,
	873	+};
	874	+
	875	+ATTRIBUTE_GROUPS(stm_source);
	876	+
	877	+static struct class stm_source_class = {
	878	+ .name = "stm_source",
	879	+ .dev_groups = stm_source_groups,
	880	+};
	881	+
	882	+static void stm_source_device_release(struct device *dev)
	883	+{
	884	+ struct stm_source_device *src = to_stm_source_device(dev);
	885	+
	886	+ kfree(src);
	887	+}
	888	+
	889	+/**
	890	+ * stm_source_register_device() - register an stm_source device
	891	+ * @parent: parent device
	892	+ * @data: device description structure
	893	+ *
	894	+ * This will create a device of stm_source class that can write
	895	+ * data to an stm device once linked.
	896	+ *
	897	+ * Return: 0 on success, -errno otherwise.
	898	+ */
	899	+int stm_source_register_device(struct device *parent,
	900	+ struct stm_source_data *data)
	901	+{
	902	+ struct stm_source_device *src;
	903	+ int err;
	904	+
	905	+ if (!stm_core_up)
	906	+ return -EPROBE_DEFER;
	907	+
	908	+ src = kzalloc(sizeof(*src), GFP_KERNEL);
	909	+ if (!src)
	910	+ return -ENOMEM;
	911	+
	912	+ device_initialize(&src->dev);
	913	+ src->dev.class = &stm_source_class;
	914	+ src->dev.parent = parent;
	915	+ src->dev.release = stm_source_device_release;
	916	+
	917	+ err = kobject_set_name(&src->dev.kobj, "%s", data->name);
	918	+ if (err)
	919	+ goto err;
	920	+
	921	+ err = device_add(&src->dev);
	922	+ if (err)
	923	+ goto err;
	924	+
	925	+ spin_lock_init(&src->link_lock);
	926	+ INIT_LIST_HEAD(&src->link_entry);
	927	+ src->data = data;
	928	+ data->src = src;
	929	+
	930	+ return 0;
	931	+
	932	+err:
	933	+ put_device(&src->dev);
	934	+ kfree(src);
	935	+
	936	+ return err;
	937	+}
	938	+EXPORT_SYMBOL_GPL(stm_source_register_device);
	939	+
	940	+/**
	941	+ * stm_source_unregister_device() - unregister an stm_source device
	942	+ * @data: device description that was used to register the device
	943	+ *
	944	+ * This will remove a previously created stm_source device from the system.
	945	+ */
	946	+void stm_source_unregister_device(struct stm_source_data *data)
	947	+{
	948	+ struct stm_source_device *src = data->src;
	949	+
	950	+ stm_source_link_drop(src);
	951	+
	952	+ device_destroy(&stm_source_class, src->dev.devt);
	953	+}
	954	+EXPORT_SYMBOL_GPL(stm_source_unregister_device);
	955	+
	956	+int stm_source_write(struct stm_source_data *data, unsigned int chan,
	957	+ const char *buf, size_t count)
	958	+{
	959	+ struct stm_source_device *src = data->src;
	960	+ struct stm_device *stm;
	961	+ int idx;
	962	+
	963	+ if (!src->output.nr_chans)
	964	+ return -ENODEV;
	965	+
	966	+ if (chan >= src->output.nr_chans)
	967	+ return -EINVAL;
	968	+
	969	+ idx = srcu_read_lock(&stm_source_srcu);
	970	+
	971	+ stm = srcu_dereference(src->link, &stm_source_srcu);
	972	+ if (stm)
	973	+ stm_write(stm->data, src->output.master,
	974	+ src->output.channel + chan,
	975	+ buf, count);
	976	+ else
	977	+ count = -ENODEV;
	978	+
	979	+ srcu_read_unlock(&stm_source_srcu, idx);
	980	+
	981	+ return count;
	982	+}
	983	+EXPORT_SYMBOL_GPL(stm_source_write);
	984	+
	985	+static int __init stm_core_init(void)
	986	+{
	987	+ int err;
	988	+
	989	+ err = class_register(&stm_class);
	990	+ if (err)
	991	+ return err;
	992	+
	993	+ err = class_register(&stm_source_class);
	994	+ if (err)
	995	+ goto err_stm;
	996	+
	997	+ err = stp_configfs_init();
	998	+ if (err)
	999	+ goto err_src;
	1000	+
	1001	+ init_srcu_struct(&stm_source_srcu);
	1002	+
	1003	+ stm_core_up++;
	1004	+
	1005	+ return 0;
	1006	+
	1007	+err_src:
	1008	+ class_unregister(&stm_source_class);
	1009	+err_stm:
	1010	+ class_unregister(&stm_class);
	1011	+
	1012	+ return err;
	1013	+}
	1014	+
	1015	+module_init(stm_core_init);
	1016	+
	1017	+static void __exit stm_core_exit(void)
	1018	+{
	1019	+ cleanup_srcu_struct(&stm_source_srcu);
	1020	+ class_unregister(&stm_source_class);
	1021	+ class_unregister(&stm_class);
	1022	+ stp_configfs_exit();
	1023	+}
	1024	+
	1025	+module_exit(stm_core_exit);
	1026	+
	1027	+MODULE_LICENSE("GPL v2");
	1028	+MODULE_DESCRIPTION("System Trace Module device class");
	1029	+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");

drivers/hwtracing/stm/policy.c+529−0

@@ -0,0 +1,529 @@
	1	+/*
	2	+ * System Trace Module (STM) master/channel allocation policy management
	3	+ * Copyright (c) 2014, Intel Corporation.
	4	+ *
	5	+ * This program is free software; you can redistribute it and/or modify it
	6	+ * under the terms and conditions of the GNU General Public License,
	7	+ * version 2, as published by the Free Software Foundation.
	8	+ *
	9	+ * This program is distributed in the hope it will be useful, but WITHOUT
	10	+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	12	+ * more details.
	13	+ *
	14	+ * A master/channel allocation policy allows mapping string identifiers to
	15	+ * master and channel ranges, where allocation can be done.
	16	+ */
	17	+
	18	+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	19	+
	20	+#include <linux/types.h>
	21	+#include <linux/module.h>
	22	+#include <linux/device.h>
	23	+#include <linux/configfs.h>
	24	+#include <linux/slab.h>
	25	+#include <linux/stm.h>
	26	+#include "stm.h"
	27	+
	28	+/*
	29	+ * STP Master/Channel allocation policy configfs layout.
	30	+ */
	31	+
	32	+struct stp_policy {
	33	+ struct config_group group;
	34	+ struct stm_device *stm;
	35	+};
	36	+
	37	+struct stp_policy_node {
	38	+ struct config_group group;
	39	+ struct stp_policy *policy;
	40	+ unsigned int first_master;
	41	+ unsigned int last_master;
	42	+ unsigned int first_channel;
	43	+ unsigned int last_channel;
	44	+};
	45	+
	46	+static struct configfs_subsystem stp_policy_subsys;
	47	+
	48	+void stp_policy_node_get_ranges(struct stp_policy_node *policy_node,
	49	+ unsigned int mstart, unsigned int mend,
	50	+ unsigned int cstart, unsigned int cend)
	51	+{
	52	+ *mstart = policy_node->first_master;
	53	+ *mend = policy_node->last_master;
	54	+ *cstart = policy_node->first_channel;
	55	+ *cend = policy_node->last_channel;
	56	+}
	57	+
	58	+static inline char stp_policy_node_name(struct stp_policy_node policy_node)
	59	+{
	60	+ return policy_node->group.cg_item.ci_name ? : "<none>";
	61	+}
	62	+
	63	+static inline struct stp_policy to_stp_policy(struct config_item item)
	64	+{
	65	+ return item ?
	66	+ container_of(to_config_group(item), struct stp_policy, group) :
	67	+ NULL;
	68	+}
	69	+
	70	+static inline struct stp_policy_node *
	71	+to_stp_policy_node(struct config_item *item)
	72	+{
	73	+ return item ?
	74	+ container_of(to_config_group(item), struct stp_policy_node,
	75	+ group) :
	76	+ NULL;
	77	+}
	78	+
	79	+static ssize_t stp_policy_node_masters_show(struct stp_policy_node *policy_node,
	80	+ char *page)
	81	+{
	82	+ ssize_t count;
	83	+
	84	+ count = sprintf(page, "%u %u\n", policy_node->first_master,
	85	+ policy_node->last_master);
	86	+
	87	+ return count;
	88	+}
	89	+
	90	+static ssize_t
	91	+stp_policy_node_masters_store(struct stp_policy_node *policy_node,
	92	+ const char *page, size_t count)
	93	+{
	94	+ unsigned int first, last;
	95	+ struct stm_device *stm;
	96	+ char p = (char )page;
	97	+ ssize_t ret = -ENODEV;
	98	+
	99	+ if (sscanf(p, "%u %u", &first, &last) != 2)
	100	+ return -EINVAL;
	101	+
	102	+ mutex_lock(&stp_policy_subsys.su_mutex);
	103	+ stm = policy_node->policy->stm;
	104	+ if (!stm)
	105	+ goto unlock;
	106	+
	107	+ /* must be within [sw_start..sw_end], which is an inclusive range */
	108	+ if (first > INT_MAX \|\| last > INT_MAX \|\| first > last \|\|
	109	+ first < stm->data->sw_start \|\|
	110	+ last > stm->data->sw_end) {
	111	+ ret = -ERANGE;
	112	+ goto unlock;
	113	+ }
	114	+
	115	+ ret = count;
	116	+ policy_node->first_master = first;
	117	+ policy_node->last_master = last;
	118	+
	119	+unlock:
	120	+ mutex_unlock(&stp_policy_subsys.su_mutex);
	121	+
	122	+ return ret;
	123	+}
	124	+
	125	+static ssize_t
	126	+stp_policy_node_channels_show(struct stp_policy_node policy_node, char page)
	127	+{
	128	+ ssize_t count;
	129	+
	130	+ count = sprintf(page, "%u %u\n", policy_node->first_channel,
	131	+ policy_node->last_channel);
	132	+
	133	+ return count;
	134	+}
	135	+
	136	+static ssize_t
	137	+stp_policy_node_channels_store(struct stp_policy_node *policy_node,
	138	+ const char *page, size_t count)
	139	+{
	140	+ unsigned int first, last;
	141	+ struct stm_device *stm;
	142	+ char p = (char )page;
	143	+ ssize_t ret = -ENODEV;
	144	+
	145	+ if (sscanf(p, "%u %u", &first, &last) != 2)
	146	+ return -EINVAL;
	147	+
	148	+ mutex_lock(&stp_policy_subsys.su_mutex);
	149	+ stm = policy_node->policy->stm;
	150	+ if (!stm)
	151	+ goto unlock;
	152	+
	153	+ if (first > INT_MAX \|\| last > INT_MAX \|\| first > last \|\|
	154	+ last >= stm->data->sw_nchannels) {
	155	+ ret = -ERANGE;
	156	+ goto unlock;
	157	+ }
	158	+
	159	+ ret = count;
	160	+ policy_node->first_channel = first;
	161	+ policy_node->last_channel = last;
	162	+
	163	+unlock:
	164	+ mutex_unlock(&stp_policy_subsys.su_mutex);
	165	+
	166	+ return ret;
	167	+}
	168	+
	169	+static void stp_policy_node_release(struct config_item *item)
	170	+{
	171	+ kfree(to_stp_policy_node(item));
	172	+}
	173	+
	174	+struct stp_policy_node_attribute {
	175	+ struct configfs_attribute attr;
	176	+ ssize_t (show)(struct stp_policy_node , char *);
	177	+ ssize_t (store)(struct stp_policy_node , const char *, size_t);
	178	+};
	179	+
	180	+static ssize_t stp_policy_node_attr_show(struct config_item *item,
	181	+ struct configfs_attribute *attr,
	182	+ char *page)
	183	+{
	184	+ struct stp_policy_node *policy_node = to_stp_policy_node(item);
	185	+ struct stp_policy_node_attribute *pn_attr =
	186	+ container_of(attr, struct stp_policy_node_attribute, attr);
	187	+ ssize_t count = 0;
	188	+
	189	+ if (pn_attr->show)
	190	+ count = pn_attr->show(policy_node, page);
	191	+
	192	+ return count;
	193	+}
	194	+
	195	+static ssize_t stp_policy_node_attr_store(struct config_item *item,
	196	+ struct configfs_attribute *attr,
	197	+ const char *page, size_t len)
	198	+{
	199	+ struct stp_policy_node *policy_node = to_stp_policy_node(item);
	200	+ struct stp_policy_node_attribute *pn_attr =
	201	+ container_of(attr, struct stp_policy_node_attribute, attr);
	202	+ ssize_t count = -EINVAL;
	203	+
	204	+ if (pn_attr->store)
	205	+ count = pn_attr->store(policy_node, page, len);
	206	+
	207	+ return count;
	208	+}
	209	+
	210	+static struct configfs_item_operations stp_policy_node_item_ops = {
	211	+ .release = stp_policy_node_release,
	212	+ .show_attribute = stp_policy_node_attr_show,
	213	+ .store_attribute = stp_policy_node_attr_store,
	214	+};
	215	+
	216	+static struct stp_policy_node_attribute stp_policy_node_attr_range = {
	217	+ .attr = {
	218	+ .ca_owner = THIS_MODULE,
	219	+ .ca_name = "masters",
	220	+ .ca_mode = S_IRUGO \| S_IWUSR,
	221	+ },
	222	+ .show = stp_policy_node_masters_show,
	223	+ .store = stp_policy_node_masters_store,
	224	+};
	225	+
	226	+static struct stp_policy_node_attribute stp_policy_node_attr_channels = {
	227	+ .attr = {
	228	+ .ca_owner = THIS_MODULE,
	229	+ .ca_name = "channels",
	230	+ .ca_mode = S_IRUGO \| S_IWUSR,
	231	+ },
	232	+ .show = stp_policy_node_channels_show,
	233	+ .store = stp_policy_node_channels_store,
	234	+};
	235	+
	236	+static struct configfs_attribute *stp_policy_node_attrs[] = {
	237	+ &stp_policy_node_attr_range.attr,
	238	+ &stp_policy_node_attr_channels.attr,
	239	+ NULL,
	240	+};
	241	+
	242	+static struct config_item_type stp_policy_type;
	243	+static struct config_item_type stp_policy_node_type;
	244	+
	245	+static struct config_group *
	246	+stp_policy_node_make(struct config_group group, const char name)
	247	+{
	248	+ struct stp_policy_node policy_node, parent_node;
	249	+ struct stp_policy *policy;
	250	+
	251	+ if (group->cg_item.ci_type == &stp_policy_type) {
	252	+ policy = container_of(group, struct stp_policy, group);
	253	+ } else {
	254	+ parent_node = container_of(group, struct stp_policy_node,
	255	+ group);
	256	+ policy = parent_node->policy;
	257	+ }
	258	+
	259	+ if (!policy->stm)
	260	+ return ERR_PTR(-ENODEV);
	261	+
	262	+ policy_node = kzalloc(sizeof(struct stp_policy_node), GFP_KERNEL);
	263	+ if (!policy_node)
	264	+ return ERR_PTR(-ENOMEM);
	265	+
	266	+ config_group_init_type_name(&policy_node->group, name,
	267	+ &stp_policy_node_type);
	268	+
	269	+ policy_node->policy = policy;
	270	+
	271	+ /* default values for the attributes */
	272	+ policy_node->first_master = policy->stm->data->sw_start;
	273	+ policy_node->last_master = policy->stm->data->sw_end;
	274	+ policy_node->first_channel = 0;
	275	+ policy_node->last_channel = policy->stm->data->sw_nchannels - 1;
	276	+
	277	+ return &policy_node->group;
	278	+}
	279	+
	280	+static void
	281	+stp_policy_node_drop(struct config_group group, struct config_item item)
	282	+{
	283	+ config_item_put(item);
	284	+}
	285	+
	286	+static struct configfs_group_operations stp_policy_node_group_ops = {
	287	+ .make_group = stp_policy_node_make,
	288	+ .drop_item = stp_policy_node_drop,
	289	+};
	290	+
	291	+static struct config_item_type stp_policy_node_type = {
	292	+ .ct_item_ops = &stp_policy_node_item_ops,
	293	+ .ct_group_ops = &stp_policy_node_group_ops,
	294	+ .ct_attrs = stp_policy_node_attrs,
	295	+ .ct_owner = THIS_MODULE,
	296	+};
	297	+
	298	+/*
	299	+ * Root group: policies.
	300	+ */
	301	+static struct configfs_attribute stp_policy_attr_device = {
	302	+ .ca_owner = THIS_MODULE,
	303	+ .ca_name = "device",
	304	+ .ca_mode = S_IRUGO,
	305	+};
	306	+
	307	+static struct configfs_attribute *stp_policy_attrs[] = {
	308	+ &stp_policy_attr_device,
	309	+ NULL,
	310	+};
	311	+
	312	+static ssize_t stp_policy_attr_show(struct config_item *item,
	313	+ struct configfs_attribute *attr,
	314	+ char *page)
	315	+{
	316	+ struct stp_policy *policy = to_stp_policy(item);
	317	+ ssize_t count;
	318	+
	319	+ count = sprintf(page, "%s\n",
	320	+ (policy && policy->stm) ?
	321	+ policy->stm->data->name :
	322	+ "<none>");
	323	+
	324	+ return count;
	325	+}
	326	+
	327	+void stp_policy_unbind(struct stp_policy *policy)
	328	+{
	329	+ struct stm_device *stm = policy->stm;
	330	+
	331	+ if (WARN_ON_ONCE(!policy->stm))
	332	+ return;
	333	+
	334	+ mutex_lock(&stm->policy_mutex);
	335	+ stm->policy = NULL;
	336	+ mutex_unlock(&stm->policy_mutex);
	337	+
	338	+ policy->stm = NULL;
	339	+
	340	+ stm_put_device(stm);
	341	+}
	342	+
	343	+static void stp_policy_release(struct config_item *item)
	344	+{
	345	+ struct stp_policy *policy = to_stp_policy(item);
	346	+
	347	+ stp_policy_unbind(policy);
	348	+ kfree(policy);
	349	+}
	350	+
	351	+static struct configfs_item_operations stp_policy_item_ops = {
	352	+ .release = stp_policy_release,
	353	+ .show_attribute = stp_policy_attr_show,
	354	+};
	355	+
	356	+static struct configfs_group_operations stp_policy_group_ops = {
	357	+ .make_group = stp_policy_node_make,
	358	+};
	359	+
	360	+static struct config_item_type stp_policy_type = {
	361	+ .ct_item_ops = &stp_policy_item_ops,
	362	+ .ct_group_ops = &stp_policy_group_ops,
	363	+ .ct_attrs = stp_policy_attrs,
	364	+ .ct_owner = THIS_MODULE,
	365	+};
	366	+
	367	+static struct config_group *
	368	+stp_policies_make(struct config_group group, const char name)
	369	+{
	370	+ struct config_group *ret;
	371	+ struct stm_device *stm;
	372	+ char devname, p;
	373	+
	374	+ devname = kasprintf(GFP_KERNEL, "%s", name);
	375	+ if (!devname)
	376	+ return ERR_PTR(-ENOMEM);
	377	+
	378	+ /*
	379	+ * node must look like <device_name>.<policy_name>, where
	380	+ * <device_name> is the name of an existing stm device and
	381	+ * <policy_name> is an arbitrary string
	382	+ */
	383	+ p = strchr(devname, '.');
	384	+ if (!p) {
	385	+ kfree(devname);
	386	+ return ERR_PTR(-EINVAL);
	387	+ }
	388	+
	389	+ *p++ = '\0';
	390	+
	391	+ stm = stm_find_device(devname);
	392	+ kfree(devname);
	393	+
	394	+ if (!stm)
	395	+ return ERR_PTR(-ENODEV);
	396	+
	397	+ mutex_lock(&stm->policy_mutex);
	398	+ if (stm->policy) {
	399	+ ret = ERR_PTR(-EBUSY);
	400	+ goto unlock_policy;
	401	+ }
	402	+
	403	+ stm->policy = kzalloc(sizeof(*stm->policy), GFP_KERNEL);
	404	+ if (!stm->policy) {
	405	+ ret = ERR_PTR(-ENOMEM);
	406	+ goto unlock_policy;
	407	+ }
	408	+
	409	+ config_group_init_type_name(&stm->policy->group, name,
	410	+ &stp_policy_type);
	411	+ stm->policy->stm = stm;
	412	+
	413	+ ret = &stm->policy->group;
	414	+
	415	+unlock_policy:
	416	+ mutex_unlock(&stm->policy_mutex);
	417	+
	418	+ if (IS_ERR(ret))
	419	+ stm_put_device(stm);
	420	+
	421	+ return ret;
	422	+}
	423	+
	424	+static struct configfs_group_operations stp_policies_group_ops = {
	425	+ .make_group = stp_policies_make,
	426	+};
	427	+
	428	+static struct config_item_type stp_policies_type = {
	429	+ .ct_group_ops = &stp_policies_group_ops,
	430	+ .ct_owner = THIS_MODULE,
	431	+};
	432	+
	433	+static struct configfs_subsystem stp_policy_subsys = {
	434	+ .su_group = {
	435	+ .cg_item = {
	436	+ .ci_namebuf = "stp-policy",
	437	+ .ci_type = &stp_policies_type,
	438	+ },
	439	+ },
	440	+};
	441	+
	442	+/*
	443	+ * Lock the policy mutex from the outside
	444	+ */
	445	+static struct stp_policy_node *
	446	+__stp_policy_node_lookup(struct stp_policy policy, char s)
	447	+{
	448	+ struct stp_policy_node policy_node, ret;
	449	+ struct list_head *head = &policy->group.cg_children;
	450	+ struct config_item *item;
	451	+ char start, end = s;
	452	+
	453	+ if (list_empty(head))
	454	+ return NULL;
	455	+
	456	+ /* return the first entry if everything else fails */
	457	+ item = list_entry(head->next, struct config_item, ci_entry);
	458	+ ret = to_stp_policy_node(item);
	459	+
	460	+next:
	461	+ for (;;) {
	462	+ start = strsep(&end, "/");
	463	+ if (!start)
	464	+ break;
	465	+
	466	+ if (!*start)
	467	+ continue;
	468	+
	469	+ list_for_each_entry(item, head, ci_entry) {
	470	+ policy_node = to_stp_policy_node(item);
	471	+
	472	+ if (!strcmp(start,
	473	+ policy_node->group.cg_item.ci_name)) {
	474	+ ret = policy_node;
	475	+
	476	+ if (!end)
	477	+ goto out;
	478	+
	479	+ head = &policy_node->group.cg_children;
	480	+ goto next;
	481	+ }
	482	+ }
	483	+ break;
	484	+ }
	485	+
	486	+out:
	487	+ return ret;
	488	+}
	489	+
	490	+
	491	+struct stp_policy_node *
	492	+stp_policy_node_lookup(struct stm_device stm, char s)
	493	+{
	494	+ struct stp_policy_node *policy_node = NULL;
	495	+
	496	+ mutex_lock(&stp_policy_subsys.su_mutex);
	497	+
	498	+ mutex_lock(&stm->policy_mutex);
	499	+ if (stm->policy)
	500	+ policy_node = __stp_policy_node_lookup(stm->policy, s);
	501	+ mutex_unlock(&stm->policy_mutex);
	502	+
	503	+ if (policy_node)
	504	+ config_item_get(&policy_node->group.cg_item);
	505	+ mutex_unlock(&stp_policy_subsys.su_mutex);
	506	+
	507	+ return policy_node;
	508	+}
	509	+
	510	+void stp_policy_node_put(struct stp_policy_node *policy_node)
	511	+{
	512	+ config_item_put(&policy_node->group.cg_item);
	513	+}
	514	+
	515	+int __init stp_configfs_init(void)
	516	+{
	517	+ int err;
	518	+
	519	+ config_group_init(&stp_policy_subsys.su_group);
	520	+ mutex_init(&stp_policy_subsys.su_mutex);
	521	+ err = configfs_register_subsystem(&stp_policy_subsys);
	522	+
	523	+ return err;
	524	+}
	525	+
	526	+void __exit stp_configfs_exit(void)
	527	+{
	528	+ configfs_unregister_subsystem(&stp_policy_subsys);
	529	+}

drivers/hwtracing/stm/stm.h+87−0

@@ -0,0 +1,87 @@
	1	+/*
	2	+ * System Trace Module (STM) infrastructure
	3	+ * Copyright (c) 2014, Intel Corporation.
	4	+ *
	5	+ * This program is free software; you can redistribute it and/or modify it
	6	+ * under the terms and conditions of the GNU General Public License,
	7	+ * version 2, as published by the Free Software Foundation.
	8	+ *
	9	+ * This program is distributed in the hope it will be useful, but WITHOUT
	10	+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	12	+ * more details.
	13	+ *
	14	+ * STM class implements generic infrastructure for System Trace Module devices
	15	+ * as defined in MIPI STPv2 specification.
	16	+ */
	17	+
	18	+#ifndef _STM_STM_H_
	19	+#define _STM_STM_H_
	20	+
	21	+struct stp_policy;
	22	+struct stp_policy_node;
	23	+
	24	+struct stp_policy_node *
	25	+stp_policy_node_lookup(struct stm_device stm, char s);
	26	+void stp_policy_node_put(struct stp_policy_node *policy_node);
	27	+void stp_policy_unbind(struct stp_policy *policy);
	28	+
	29	+void stp_policy_node_get_ranges(struct stp_policy_node *policy_node,
	30	+ unsigned int mstart, unsigned int mend,
	31	+ unsigned int cstart, unsigned int cend);
	32	+int stp_configfs_init(void);
	33	+void stp_configfs_exit(void);
	34	+
	35	+struct stp_master {
	36	+ unsigned int nr_free;
	37	+ unsigned long chan_map[0];
	38	+};
	39	+
	40	+struct stm_device {
	41	+ struct device dev;
	42	+ struct module *owner;
	43	+ struct stp_policy *policy;
	44	+ struct mutex policy_mutex;
	45	+ int major;
	46	+ unsigned int sw_nmasters;
	47	+ struct stm_data *data;
	48	+ spinlock_t link_lock;
	49	+ struct list_head link_list;
	50	+ /* master allocation */
	51	+ spinlock_t mc_lock;
	52	+ struct stp_master *masters[0];
	53	+};
	54	+
	55	+#define to_stm_device(_d) \
	56	+ container_of((_d), struct stm_device, dev)
	57	+
	58	+struct stm_output {
	59	+ unsigned int master;
	60	+ unsigned int channel;
	61	+ unsigned int nr_chans;
	62	+};
	63	+
	64	+struct stm_file {
	65	+ struct stm_device *stm;
	66	+ struct stp_policy_node *policy_node;
	67	+ struct stm_output output;
	68	+};
	69	+
	70	+struct stm_device stm_find_device(const char name);
	71	+void stm_put_device(struct stm_device *stm);
	72	+
	73	+struct stm_source_device {
	74	+ struct device dev;
	75	+ struct stm_source_data *data;
	76	+ spinlock_t link_lock;
	77	+ struct stm_device *link;
	78	+ struct list_head link_entry;
	79	+ /* one output per stm_source device */
	80	+ struct stp_policy_node *policy_node;
	81	+ struct stm_output output;
	82	+};
	83	+
	84	+#define to_stm_source_device(_d) \
	85	+ container_of((_d), struct stm_source_device, dev)
	86	+
	87	+#endif /* _STM_STM_H_ */

include/linux/stm.h+126−0

@@ -0,0 +1,126 @@
	1	+/*
	2	+ * System Trace Module (STM) infrastructure apis
	3	+ * Copyright (C) 2014 Intel Corporation.
	4	+ *
	5	+ * This program is free software; you can redistribute it and/or modify it
	6	+ * under the terms and conditions of the GNU General Public License,
	7	+ * version 2, as published by the Free Software Foundation.
	8	+ *
	9	+ * This program is distributed in the hope it will be useful, but WITHOUT
	10	+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	12	+ * more details.
	13	+ */
	14	+
	15	+#ifndef _STM_H_
	16	+#define _STM_H_
	17	+
	18	+#include <linux/device.h>
	19	+
	20	+/**
	21	+ * enum stp_packet_type - STP packets that an STM driver sends
	22	+ */
	23	+enum stp_packet_type {
	24	+ STP_PACKET_DATA = 0,
	25	+ STP_PACKET_FLAG,
	26	+ STP_PACKET_USER,
	27	+ STP_PACKET_MERR,
	28	+ STP_PACKET_GERR,
	29	+ STP_PACKET_TRIG,
	30	+ STP_PACKET_XSYNC,
	31	+};
	32	+
	33	+/**
	34	+ * enum stp_packet_flags - STP packet modifiers
	35	+ */
	36	+enum stp_packet_flags {
	37	+ STP_PACKET_MARKED = 0x1,
	38	+ STP_PACKET_TIMESTAMPED = 0x2,
	39	+};
	40	+
	41	+struct stp_policy;
	42	+
	43	+struct stm_device;
	44	+
	45	+/**
	46	+ * struct stm_data - STM device description and callbacks
	47	+ * @name: device name
	48	+ * @stm: internal structure, only used by stm class code
	49	+ * @sw_start: first STP master available to software
	50	+ * @sw_end: last STP master available to software
	51	+ * @sw_nchannels: number of STP channels per master
	52	+ * @sw_mmiosz: size of one channel's IO space, for mmap, optional
	53	+ * @packet: callback that sends an STP packet
	54	+ * @mmio_addr: mmap callback, optional
	55	+ * @link: called when a new stm_source gets linked to us, optional
	56	+ * @unlink: likewise for unlinking, again optional
	57	+ * @set_options: set device-specific options on a channel
	58	+ *
	59	+ * Fill out this structure before calling stm_register_device() to create
	60	+ * an STM device and stm_unregister_device() to destroy it. It will also be
	61	+ * passed back to @packet(), @mmio_addr(), @link(), @unlink() and @set_options()
	62	+ * callbacks.
	63	+ *
	64	+ * Normally, an STM device will have a range of masters available to software
	65	+ * and the rest being statically assigned to various hardware trace sources.
	66	+ * The former is defined by the the range [@sw_start..@sw_end] of the device
	67	+ * description. That is, the lowest master that can be allocated to software
	68	+ * writers is @sw_start and data from this writer will appear is @sw_start
	69	+ * master in the STP stream.
	70	+ */
	71	+struct stm_data {
	72	+ const char *name;
	73	+ struct stm_device *stm;
	74	+ unsigned int sw_start;
	75	+ unsigned int sw_end;
	76	+ unsigned int sw_nchannels;
	77	+ unsigned int sw_mmiosz;
	78	+ ssize_t (packet)(struct stm_data , unsigned int,
	79	+ unsigned int, unsigned int,
	80	+ unsigned int, unsigned int,
	81	+ const unsigned char *);
	82	+ phys_addr_t (mmio_addr)(struct stm_data , unsigned int,
	83	+ unsigned int, unsigned int);
	84	+ int (link)(struct stm_data , unsigned int,
	85	+ unsigned int);
	86	+ void (unlink)(struct stm_data , unsigned int,
	87	+ unsigned int);
	88	+ long (set_options)(struct stm_data , unsigned int,
	89	+ unsigned int, unsigned int,
	90	+ unsigned long);
	91	+};
	92	+
	93	+int stm_register_device(struct device parent, struct stm_data stm_data,
	94	+ struct module *owner);
	95	+void stm_unregister_device(struct stm_data *stm_data);
	96	+
	97	+struct stm_source_device;
	98	+
	99	+/**
	100	+ * struct stm_source_data - STM source device description and callbacks
	101	+ * @name: device name, will be used for policy lookup
	102	+ * @src: internal structure, only used by stm class code
	103	+ * @nr_chans: number of channels to allocate
	104	+ * @link: called when this source gets linked to an STM device
	105	+ * @unlink: called when this source is about to get unlinked from its STM
	106	+ *
	107	+ * Fill in this structure before calling stm_source_register_device() to
	108	+ * register a source device. Also pass it to unregister and write calls.
	109	+ */
	110	+struct stm_source_data {
	111	+ const char *name;
	112	+ struct stm_source_device *src;
	113	+ unsigned int percpu;
	114	+ unsigned int nr_chans;
	115	+ int (link)(struct stm_source_data data);
	116	+ void (unlink)(struct stm_source_data data);
	117	+};
	118	+
	119	+int stm_source_register_device(struct device *parent,
	120	+ struct stm_source_data *data);
	121	+void stm_source_unregister_device(struct stm_source_data *data);
	122	+
	123	+int stm_source_write(struct stm_source_data *data, unsigned int chan,
	124	+ const char *buf, size_t count);
	125	+
	126	+#endif /* _STM_H_ */

include/uapi/linux/stm.h+50−0

@@ -0,0 +1,50 @@
	1	+/*
	2	+ * System Trace Module (STM) userspace interfaces
	3	+ * Copyright (c) 2014, Intel Corporation.
	4	+ *
	5	+ * This program is free software; you can redistribute it and/or modify it
	6	+ * under the terms and conditions of the GNU General Public License,
	7	+ * version 2, as published by the Free Software Foundation.
	8	+ *
	9	+ * This program is distributed in the hope it will be useful, but WITHOUT
	10	+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	12	+ * more details.
	13	+ *
	14	+ * STM class implements generic infrastructure for System Trace Module devices
	15	+ * as defined in MIPI STPv2 specification.
	16	+ */
	17	+
	18	+#ifndef _UAPI_LINUX_STM_H
	19	+#define _UAPI_LINUX_STM_H
	20	+
	21	+#include <linux/types.h>
	22	+
	23	+/**
	24	+ * struct stp_policy_id - identification for the STP policy
	25	+ * @size: size of the structure including real id[] length
	26	+ * @master: assigned master
	27	+ * @channel: first assigned channel
	28	+ * @width: number of requested channels
	29	+ * @id: identification string
	30	+ *
	31	+ * User must calculate the total size of the structure and put it into
	32	+ * @size field, fill out the @id and desired @width. In return, kernel
	33	+ * fills out @master, @channel and @width.
	34	+ */
	35	+struct stp_policy_id {
	36	+ __u32 size;
	37	+ __u16 master;
	38	+ __u16 channel;
	39	+ __u16 width;
	40	+ /* padding */
	41	+ __u16 __reserved_0;
	42	+ __u32 __reserved_1;
	43	+ char id[0];
	44	+};
	45	+
	46	+#define STP_POLICY_ID_SET _IOWR('%', 0, struct stp_policy_id)
	47	+#define STP_POLICY_ID_GET _IOR('%', 1, struct stp_policy_id)
	48	+#define STP_SET_OPTIONS _IOW('%', 2, __u64)
	49	+
	50	+#endif /* _UAPI_LINUX_STM_H */

stm class: Introduce an abstraction for System Trace Module devices

Keyboard shortcuts

General

Issues and pull requests

Issues, pull requests and Inbox

Repository code