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kernel
os
linux
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.
Cc: linux-api@vger.kernel.org
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
authored by
Alexander Shishkin
and committed by
Greg Kroah-Hartman
7bd1d409
9b76968d
+1991
+48
Documentation/ABI/testing/configfs-stp-policy
+48
Documentation/ABI/testing/configfs-stp-policy
···
1
+
What: /config/stp-policy
2
+
Date: June 2015
3
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KernelVersion: 4.3
4
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Description:
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This group contains policies mandating Master/Channel allocation
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for software sources wishing to send trace data over an STM
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device.
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+
9
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What: /config/stp-policy/<device>.<policy>
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Date: June 2015
11
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KernelVersion: 4.3
12
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Description:
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This group is the root of a policy; its name is a concatenation
14
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of an stm device name to which this policy applies and an
15
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arbitrary string. If <device> part doesn't match an existing
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stm device, mkdir will fail with ENODEV; if that device already
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has a policy assigned to it, mkdir will fail with EBUSY.
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What: /config/stp-policy/<device>.<policy>/device
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Date: June 2015
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KernelVersion: 4.3
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Description:
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STM device to which this policy applies, read only. Same as the
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<device> component of its parent directory.
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+
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What: /config/stp-policy/<device>.<policy>/<node>
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Date: June 2015
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KernelVersion: 4.3
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Description:
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Policy node is a string identifier that software clients will
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use to request a master/channel to be allocated and assigned to
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them.
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+
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What: /config/stp-policy/<device>.<policy>/<node>/masters
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Date: June 2015
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KernelVersion: 4.3
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Description:
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Range of masters from which to allocate for users of this node.
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Write two numbers: the first master and the last master number.
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What: /config/stp-policy/<device>.<policy>/<node>/channels
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Date: June 2015
43
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KernelVersion: 4.3
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Description:
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Range of channels from which to allocate for users of this node.
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Write two numbers: the first channel and the last channel
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number.
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+14
Documentation/ABI/testing/sysfs-class-stm
+14
Documentation/ABI/testing/sysfs-class-stm
···
1
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What: /sys/class/stm/<stm>/masters
2
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Date: June 2015
3
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KernelVersion: 4.3
4
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Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
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Description:
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Shows first and last available to software master numbers on
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this STM device.
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9
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What: /sys/class/stm/<stm>/channels
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Date: June 2015
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KernelVersion: 4.3
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Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
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Description:
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Shows the number of channels per master on this STM device.
+11
Documentation/ABI/testing/sysfs-class-stm_source
+11
Documentation/ABI/testing/sysfs-class-stm_source
···
1
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What: /sys/class/stm_source/<stm_source>/stm_source_link
2
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Date: June 2015
3
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KernelVersion: 4.3
4
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Contact: Alexander Shishkin <alexander.shishkin@linux.intel.com>
5
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Description:
6
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stm_source device linkage to stm device, where its tracing data
7
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is directed. Reads return an existing connection or "<none>" if
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this stm_source is not connected to any stm device yet.
9
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Write an existing (registered) stm device's name here to
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connect that device. If a device is already connected to this
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stm_source, it will first be disconnected.
+3
Documentation/ioctl/ioctl-number.txt
+3
Documentation/ioctl/ioctl-number.txt
···
81
81
0x22 all scsi/sg.h
82
82
'#' 00-3F IEEE 1394 Subsystem Block for the entire subsystem
83
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'$' 00-0F linux/perf_counter.h, linux/perf_event.h
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'%' 00-0F include/uapi/linux/stm.h
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System Trace Module subsystem
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<mailto:alexander.shishkin@linux.intel.com>
84
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'&' 00-07 drivers/firewire/nosy-user.h
85
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'1' 00-1F <linux/timepps.h> PPS kit from Ulrich Windl
86
89
<ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>
+80
Documentation/trace/stm.txt
+80
Documentation/trace/stm.txt
···
1
+
System Trace Module
2
+
===================
3
+
4
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System Trace Module (STM) is a device described in MIPI STP specs as
5
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STP trace stream generator. STP (System Trace Protocol) is a trace
6
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protocol multiplexing data from multiple trace sources, each one of
7
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which is assigned a unique pair of master and channel. While some of
8
+
these masters and channels are statically allocated to certain
9
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hardware trace sources, others are available to software. Software
10
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trace sources are usually free to pick for themselves any
11
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master/channel combination from this pool.
12
+
13
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On the receiving end of this STP stream (the decoder side), trace
14
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sources can only be identified by master/channel combination, so in
15
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order for the decoder to be able to make sense of the trace that
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involves multiple trace sources, it needs to be able to map those
17
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master/channel pairs to the trace sources that it understands.
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+
19
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For instance, it is helpful to know that syslog messages come on
20
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master 7 channel 15, while arbitrary user applications can use masters
21
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48 to 63 and channels 0 to 127.
22
+
23
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To solve this mapping problem, stm class provides a policy management
24
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mechanism via configfs, that allows defining rules that map string
25
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identifiers to ranges of masters and channels. If these rules (policy)
26
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are consistent with what decoder expects, it will be able to properly
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process the trace data.
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29
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This policy is a tree structure containing rules (policy_node) that
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have a name (string identifier) and a range of masters and channels
31
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associated with it, located in "stp-policy" subsystem directory in
32
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configfs. The topmost directory's name (the policy) is formatted as
33
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the STM device name to which this policy applies and and arbitrary
34
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string identifier separated by a stop. From the examle above, a rule
35
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may look like this:
36
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37
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$ ls /config/stp-policy/dummy_stm.my-policy/user
38
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channels masters
39
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$ cat /config/stp-policy/dummy_stm.my-policy/user/masters
40
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48 63
41
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$ cat /config/stp-policy/dummy_stm.my-policy/user/channels
42
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0 127
43
+
44
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which means that the master allocation pool for this rule consists of
45
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masters 48 through 63 and channel allocation pool has channels 0
46
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through 127 in it. Now, any producer (trace source) identifying itself
47
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with "user" identification string will be allocated a master and
48
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channel from within these ranges.
49
+
50
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These rules can be nested, for example, one can define a rule "dummy"
51
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under "user" directory from the example above and this new rule will
52
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be used for trace sources with the id string of "user/dummy".
53
+
54
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Trace sources have to open the stm class device's node and write their
55
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trace data into its file descriptor. In order to identify themselves
56
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to the policy, they need to do a STP_POLICY_ID_SET ioctl on this file
57
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descriptor providing their id string. Otherwise, they will be
58
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automatically allocated a master/channel pair upon first write to this
59
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file descriptor according to the "default" rule of the policy, if such
60
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exists.
61
+
62
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Some STM devices may allow direct mapping of the channel mmio regions
63
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to userspace for zero-copy writing. One mappable page (in terms of
64
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mmu) will usually contain multiple channels' mmios, so the user will
65
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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
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stm device's channel mmio region is 64 bytes and hardware page size is
68
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4096 bytes, after a successful STP_POLICY_ID_SET ioctl() call with
69
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width==64, you should be able to mmap() one page on this file
70
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descriptor and obtain direct access to an mmio region for 64 channels.
71
+
72
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For kernel-based trace sources, there is "stm_source" device
73
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class. Devices of this class can be connected and disconnected to/from
74
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stm devices at runtime via a sysfs attribute.
75
+
76
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Examples of STM devices are Intel(R) Trace Hub [1] and Coresight STM
77
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[2].
78
+
79
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[1] https://software.intel.com/sites/default/files/managed/d3/3c/intel-th-developer-manual.pdf
80
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[2] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0444b/index.html
+2
drivers/Kconfig
+2
drivers/Kconfig
+1
drivers/Makefile
+1
drivers/Makefile
+8
drivers/hwtracing/stm/Kconfig
+8
drivers/hwtracing/stm/Kconfig
···
1
+
config STM
2
+
tristate "System Trace Module devices"
3
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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.
+3
drivers/hwtracing/stm/Makefile
+3
drivers/hwtracing/stm/Makefile
+1029
drivers/hwtracing/stm/core.c
+1029
drivers/hwtracing/stm/core.c
···
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
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* 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
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* STM class implements generic infrastructure for System Trace Module devices
15
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* as defined in MIPI STPv2 specification.
16
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*/
17
+
18
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#include <linux/uaccess.h>
19
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#include <linux/kernel.h>
20
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#include <linux/module.h>
21
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#include <linux/device.h>
22
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#include <linux/compat.h>
23
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#include <linux/kdev_t.h>
24
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#include <linux/srcu.h>
25
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#include <linux/slab.h>
26
+
#include <linux/stm.h>
27
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#include <linux/fs.h>
28
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#include <linux/mm.h>
29
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#include "stm.h"
30
+
31
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#include <uapi/linux/stm.h>
32
+
33
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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
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static struct srcu_struct stm_source_srcu;
41
+
42
+
static ssize_t masters_show(struct device *dev,
43
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struct device_attribute *attr,
44
+
char *buf)
45
+
{
46
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struct stm_device *stm = to_stm_device(dev);
47
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int ret;
48
+
49
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ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end);
50
+
51
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return ret;
52
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}
53
+
54
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static DEVICE_ATTR_RO(masters);
55
+
56
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static ssize_t channels_show(struct device *dev,
57
+
struct device_attribute *attr,
58
+
char *buf)
59
+
{
60
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struct stm_device *stm = to_stm_device(dev);
61
+
int ret;
62
+
63
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ret = sprintf(buf, "%u\n", stm->data->sw_nchannels);
64
+
65
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return ret;
66
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}
67
+
68
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static DEVICE_ATTR_RO(channels);
69
+
70
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static struct attribute *stm_attrs[] = {
71
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&dev_attr_masters.attr,
72
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&dev_attr_channels.attr,
73
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NULL,
74
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};
75
+
76
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ATTRIBUTE_GROUPS(stm);
77
+
78
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static struct class stm_class = {
79
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.name = "stm",
80
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.dev_groups = stm_groups,
81
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};
82
+
83
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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
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* 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
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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
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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
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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>");
+529
drivers/hwtracing/stm/policy.c
+529
drivers/hwtracing/stm/policy.c
···
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
+
}
+87
drivers/hwtracing/stm/stm.h
+87
drivers/hwtracing/stm/stm.h
···
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_ */
+126
include/linux/stm.h
+126
include/linux/stm.h
···
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_ */
+50
include/uapi/linux/stm.h
+50
include/uapi/linux/stm.h
···
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 */