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Subject[PATCH] Documentation: coresight: covert txt to rst
Date
change the format file and adpate the text style

Signed-off-by: Phong Tran <tranmanphong@gmail.com>
---
.../trace/{coresight.txt => coresight.rst} | 296 ++++++++++++---------
Documentation/trace/index.rst | 1 +
2 files changed, 167 insertions(+), 130 deletions(-)
rename Documentation/trace/{coresight.txt => coresight.rst} (59%)

diff --git a/Documentation/trace/coresight.txt b/Documentation/trace/coresight.rst
similarity index 59%
rename from Documentation/trace/coresight.txt
rename to Documentation/trace/coresight.rst
index efbc832146e7..bea24e70cfba 100644
--- a/Documentation/trace/coresight.txt
+++ b/Documentation/trace/coresight.rst
@@ -1,5 +1,6 @@
- Coresight - HW Assisted Tracing on ARM
- ======================================
+======================================
+Coresight - HW Assisted Tracing on ARM
+======================================

Author: Mathieu Poirier <mathieu.poirier@linaro.org>
Date: September 11th, 2014
@@ -26,7 +27,7 @@ implementation, either storing the compressed stream in a memory buffer or
creating an interface to the outside world where data can be transferred to a
host without fear of filling up the onboard coresight memory buffer.

-At typical coresight system would look like this:
+At typical coresight system would look like this::

*****************************************************************
**************************** AMBA AXI ****************************===||
@@ -95,6 +96,7 @@ Acronyms and Classification

Acronyms:

+======== =============================================================
PTM: Program Trace Macrocell
ETM: Embedded Trace Macrocell
STM: System trace Macrocell
@@ -104,6 +106,7 @@ TPIU: Trace Port Interface Unit
TMC-ETR: Trace Memory Controller, configured as Embedded Trace Router
TMC-ETF: Trace Memory Controller, configured as Embedded Trace FIFO
CTI: Cross Trigger Interface
+======== =============================================================

Classification:

@@ -118,7 +121,7 @@ Misc:


Device Tree Bindings
-----------------------
+--------------------

See Documentation/devicetree/bindings/arm/coresight.txt for details.

@@ -133,57 +136,63 @@ The coresight framework provides a central point to represent, configure and
manage coresight devices on a platform. Any coresight compliant device can
register with the framework for as long as they use the right APIs:

-struct coresight_device *coresight_register(struct coresight_desc *desc);
-void coresight_unregister(struct coresight_device *csdev);
+.. c:function:: struct coresight_device *coresight_register(struct coresight_desc *desc);
+.. c:function:: void coresight_unregister(struct coresight_device *csdev);

-The registering function is taking a "struct coresight_device *csdev" and
+The registering function is taking a :code:`struct coresight_device *csdev` and
register the device with the core framework. The unregister function takes
-a reference to a "struct coresight_device", obtained at registration time.
+a reference to a :code:`struct coresight_device`, obtained at registration time.

If everything goes well during the registration process the new devices will
show up under /sys/bus/coresight/devices, as showns here for a TC2 platform:

-root:~# ls /sys/bus/coresight/devices/
-replicator 20030000.tpiu 2201c000.ptm 2203c000.etm 2203e000.etm
-20010000.etb 20040000.funnel 2201d000.ptm 2203d000.etm
-root:~#
+.. code:: console

-The functions take a "struct coresight_device", which looks like this:
+ root:~# ls /sys/bus/coresight/devices/
+ replicator 20030000.tpiu 2201c000.ptm 2203c000.etm 2203e000.etm
+ 20010000.etb 20040000.funnel 2201d000.ptm 2203d000.etm
+ root:~#

-struct coresight_desc {
- enum coresight_dev_type type;
- struct coresight_dev_subtype subtype;
- const struct coresight_ops *ops;
- struct coresight_platform_data *pdata;
- struct device *dev;
- const struct attribute_group **groups;
-};
+The functions take a :code:`struct coresight_device`, which looks like this:
+
+.. code:: c
+
+ struct coresight_desc {
+ enum coresight_dev_type type;
+ struct coresight_dev_subtype subtype;
+ const struct coresight_ops *ops;
+ struct coresight_platform_data *pdata;
+ struct device *dev;
+ const struct attribute_group **groups;
+ };


The "coresight_dev_type" identifies what the device is, i.e, source link or
sink while the "coresight_dev_subtype" will characterise that type further.

-The "struct coresight_ops" is mandatory and will tell the framework how to
+The :code:`struct coresight_ops` is mandatory and will tell the framework how to
perform base operations related to the components, each component having
-a different set of requirement. For that "struct coresight_ops_sink",
-"struct coresight_ops_link" and "struct coresight_ops_source" have been
+a different set of requirement. For that :code:`struct coresight_ops_sink,
+struct coresight_ops_link` and :code:`struct coresight_ops_source` have been
provided.

-The next field, "struct coresight_platform_data *pdata" is acquired by calling
-"of_get_coresight_platform_data()", as part of the driver's _probe routine and
-"struct device *dev" gets the device reference embedded in the "amba_device":
+The next field, :code:`struct coresight_platform_data *pdata` is acquired by calling
+:code:`of_get_coresight_platform_data()`, as part of the driver's _probe routine and
+:code:`struct device *dev` gets the device reference embedded in the :code:`amba_device`:

-static int etm_probe(struct amba_device *adev, const struct amba_id *id)
-{
- ...
- ...
- drvdata->dev = &adev->dev;
- ...
-}
+.. code:: c
+
+ static int etm_probe(struct amba_device *adev, const struct amba_id *id)
+ {
+ ...
+ ...
+ drvdata->dev = &adev->dev;
+ ...
+ }

Specific class of device (source, link, or sink) have generic operations
-that can be performed on them (see "struct coresight_ops"). The
-"**groups" is a list of sysfs entries pertaining to operations
+that can be performed on them (see :code:`struct coresight_ops`). The
+:code:`**groups` is a list of sysfs entries pertaining to operations
specific to that component only. "Implementation defined" customisations are
expected to be accessed and controlled using those entries.

@@ -204,49 +213,56 @@ There is no limit on the amount of sinks (nor sources) that can be enabled at
any given moment. As a generic operation, all device pertaining to the sink
class will have an "active" entry in sysfs:

-root:/sys/bus/coresight/devices# ls
-replicator 20030000.tpiu 2201c000.ptm 2203c000.etm 2203e000.etm
-20010000.etb 20040000.funnel 2201d000.ptm 2203d000.etm
-root:/sys/bus/coresight/devices# ls 20010000.etb
-enable_sink status trigger_cntr
-root:/sys/bus/coresight/devices# echo 1 > 20010000.etb/enable_sink
-root:/sys/bus/coresight/devices# cat 20010000.etb/enable_sink
-1
-root:/sys/bus/coresight/devices#
+.. code:: console
+
+ root:/sys/bus/coresight/devices# ls
+ replicator 20030000.tpiu 2201c000.ptm 2203c000.etm 2203e000.etm
+ 20010000.etb 20040000.funnel 2201d000.ptm 2203d000.etm
+ root:/sys/bus/coresight/devices# ls 20010000.etb
+ enable_sink status trigger_cntr
+ root:/sys/bus/coresight/devices# echo 1 > 20010000.etb/enable_sink
+ root:/sys/bus/coresight/devices# cat 20010000.etb/enable_sink
+ 1
+ root:/sys/bus/coresight/devices#

At boot time the current etm3x driver will configure the first address
comparator with "_stext" and "_etext", essentially tracing any instruction
that falls within that range. As such "enabling" a source will immediately
trigger a trace capture:

-root:/sys/bus/coresight/devices# echo 1 > 2201c000.ptm/enable_source
-root:/sys/bus/coresight/devices# cat 2201c000.ptm/enable_source
-1
-root:/sys/bus/coresight/devices# cat 20010000.etb/status
-Depth: 0x2000
-Status: 0x1
-RAM read ptr: 0x0
-RAM wrt ptr: 0x19d3 <----- The write pointer is moving
-Trigger cnt: 0x0
-Control: 0x1
-Flush status: 0x0
-Flush ctrl: 0x2001
-root:/sys/bus/coresight/devices#
+.. code:: console
+
+ root:/sys/bus/coresight/devices# echo 1 > 2201c000.ptm/enable_source
+ root:/sys/bus/coresight/devices# cat 2201c000.ptm/enable_source
+ 1
+ root:/sys/bus/coresight/devices# cat 20010000.etb/status
+ Depth: 0x2000
+ Status: 0x1
+ RAM read ptr: 0x0
+ RAM wrt ptr: 0x19d3 <----- The write pointer is moving
+ Trigger cnt: 0x0
+ Control: 0x1
+ Flush status: 0x0
+ Flush ctrl: 0x2001
+ root:/sys/bus/coresight/devices#

Trace collection is stopped the same way:

-root:/sys/bus/coresight/devices# echo 0 > 2201c000.ptm/enable_source
-root:/sys/bus/coresight/devices#
+.. code:: console
+
+ root:/sys/bus/coresight/devices# echo 0 > 2201c000.ptm/enable_source
+ root:/sys/bus/coresight/devices#

The content of the ETB buffer can be harvested directly from /dev:

-root:/sys/bus/coresight/devices# dd if=/dev/20010000.etb \
-of=~/cstrace.bin
+.. code:: console

-64+0 records in
-64+0 records out
-32768 bytes (33 kB) copied, 0.00125258 s, 26.2 MB/s
-root:/sys/bus/coresight/devices#
+ root:/sys/bus/coresight/devices# dd if=/dev/20010000.etb \
+ of=~/cstrace.bin
+ 64+0 records in
+ 64+0 records out
+ 32768 bytes (33 kB) copied, 0.00125258 s, 26.2 MB/s
+ root:/sys/bus/coresight/devices#

The file cstrace.bin can be decompressed using "ptm2human", DS-5 or Trace32.

@@ -254,55 +270,57 @@ Following is a DS-5 output of an experimental loop that increments a variable up
to a certain value. The example is simple and yet provides a glimpse of the
wealth of possibilities that coresight provides.

-Info Tracing enabled
-Instruction 106378866 0x8026B53C E52DE004 false PUSH {lr}
-Instruction 0 0x8026B540 E24DD00C false SUB sp,sp,#0xc
-Instruction 0 0x8026B544 E3A03000 false MOV r3,#0
-Instruction 0 0x8026B548 E58D3004 false STR r3,[sp,#4]
-Instruction 0 0x8026B54C E59D3004 false LDR r3,[sp,#4]
-Instruction 0 0x8026B550 E3530004 false CMP r3,#4
-Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1
-Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4]
-Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c
-Timestamp Timestamp: 17106715833
-Instruction 319 0x8026B54C E59D3004 false LDR r3,[sp,#4]
-Instruction 0 0x8026B550 E3530004 false CMP r3,#4
-Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1
-Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4]
-Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c
-Instruction 9 0x8026B54C E59D3004 false LDR r3,[sp,#4]
-Instruction 0 0x8026B550 E3530004 false CMP r3,#4
-Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1
-Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4]
-Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c
-Instruction 7 0x8026B54C E59D3004 false LDR r3,[sp,#4]
-Instruction 0 0x8026B550 E3530004 false CMP r3,#4
-Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1
-Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4]
-Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c
-Instruction 7 0x8026B54C E59D3004 false LDR r3,[sp,#4]
-Instruction 0 0x8026B550 E3530004 false CMP r3,#4
-Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1
-Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4]
-Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c
-Instruction 10 0x8026B54C E59D3004 false LDR r3,[sp,#4]
-Instruction 0 0x8026B550 E3530004 false CMP r3,#4
-Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1
-Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4]
-Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c
-Instruction 6 0x8026B560 EE1D3F30 false MRC p15,#0x0,r3,c13,c0,#1
-Instruction 0 0x8026B564 E1A0100D false MOV r1,sp
-Instruction 0 0x8026B568 E3C12D7F false BIC r2,r1,#0x1fc0
-Instruction 0 0x8026B56C E3C2203F false BIC r2,r2,#0x3f
-Instruction 0 0x8026B570 E59D1004 false LDR r1,[sp,#4]
-Instruction 0 0x8026B574 E59F0010 false LDR r0,[pc,#16] ; [0x8026B58C] = 0x80550368
-Instruction 0 0x8026B578 E592200C false LDR r2,[r2,#0xc]
-Instruction 0 0x8026B57C E59221D0 false LDR r2,[r2,#0x1d0]
-Instruction 0 0x8026B580 EB07A4CF true BL {pc}+0x1e9344 ; 0x804548c4
-Info Tracing enabled
-Instruction 13570831 0x8026B584 E28DD00C false ADD sp,sp,#0xc
-Instruction 0 0x8026B588 E8BD8000 true LDM sp!,{pc}
-Timestamp Timestamp: 17107041535
+.. code:: c
+
+ Info Tracing enabled
+ Instruction 106378866 0x8026B53C E52DE004 false PUSH {lr}
+ Instruction 0 0x8026B540 E24DD00C false SUB sp,sp,#0xc
+ Instruction 0 0x8026B544 E3A03000 false MOV r3,#0
+ Instruction 0 0x8026B548 E58D3004 false STR r3,[sp,#4]
+ Instruction 0 0x8026B54C E59D3004 false LDR r3,[sp,#4]
+ Instruction 0 0x8026B550 E3530004 false CMP r3,#4
+ Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1
+ Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4]
+ Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c
+ Timestamp Timestamp: 17106715833
+ Instruction 319 0x8026B54C E59D3004 false LDR r3,[sp,#4]
+ Instruction 0 0x8026B550 E3530004 false CMP r3,#4
+ Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1
+ Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4]
+ Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c
+ Instruction 9 0x8026B54C E59D3004 false LDR r3,[sp,#4]
+ Instruction 0 0x8026B550 E3530004 false CMP r3,#4
+ Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1
+ Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4]
+ Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c
+ Instruction 7 0x8026B54C E59D3004 false LDR r3,[sp,#4]
+ Instruction 0 0x8026B550 E3530004 false CMP r3,#4
+ Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1
+ Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4]
+ Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c
+ Instruction 7 0x8026B54C E59D3004 false LDR r3,[sp,#4]
+ Instruction 0 0x8026B550 E3530004 false CMP r3,#4
+ Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1
+ Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4]
+ Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c
+ Instruction 10 0x8026B54C E59D3004 false LDR r3,[sp,#4]
+ Instruction 0 0x8026B550 E3530004 false CMP r3,#4
+ Instruction 0 0x8026B554 E2833001 false ADD r3,r3,#1
+ Instruction 0 0x8026B558 E58D3004 false STR r3,[sp,#4]
+ Instruction 0 0x8026B55C DAFFFFFA true BLE {pc}-0x10 ; 0x8026b54c
+ Instruction 6 0x8026B560 EE1D3F30 false MRC p15,#0x0,r3,c13,c0,#1
+ Instruction 0 0x8026B564 E1A0100D false MOV r1,sp
+ Instruction 0 0x8026B568 E3C12D7F false BIC r2,r1,#0x1fc0
+ Instruction 0 0x8026B56C E3C2203F false BIC r2,r2,#0x3f
+ Instruction 0 0x8026B570 E59D1004 false LDR r1,[sp,#4]
+ Instruction 0 0x8026B574 E59F0010 false LDR r0,[pc,#16] ; [0x8026B58C] = 0x80550368
+ Instruction 0 0x8026B578 E592200C false LDR r2,[r2,#0xc]
+ Instruction 0 0x8026B57C E59221D0 false LDR r2,[r2,#0x1d0]
+ Instruction 0 0x8026B580 EB07A4CF true BL {pc}+0x1e9344 ; 0x804548c4
+ Info Tracing enabled
+ Instruction 13570831 0x8026B584 E28DD00C false ADD sp,sp,#0xc
+ Instruction 0 0x8026B588 E8BD8000 true LDM sp!,{pc}
+ Timestamp Timestamp: 17107041535

2) Using perf framework:

@@ -312,6 +330,8 @@ controlling when tracing gets enabled based on when the process of interest is
scheduled. When configured in a system, Coresight PMUs will be listed when
queried by the perf command line tool:

+.. code:: console
+
linaro@linaro-nano:~$ ./perf list pmu

List of pre-defined events (to be used in -e):
@@ -329,6 +349,8 @@ Coresight system will typically have more than one sink, the name of the sink to
work with needs to be specified as an event option. Names for sink to choose
from are listed in sysFS under ($SYSFS)/bus/coresight/devices:

+.. code:: console
+
root@linaro-nano:~# ls /sys/bus/coresight/devices/
20010000.etf 20040000.funnel 20100000.stm 22040000.etm
22140000.etm 230c0000.funnel 23240000.etm 20030000.tpiu
@@ -343,7 +365,7 @@ to use for the trace session.

More information on the above and other example on how to use Coresight with
the perf tools can be found in the "HOWTO.md" file of the openCSD gitHub
-repository [3].
+repository [#third]_.

2.1) AutoFDO analysis using the perf tools:

@@ -352,6 +374,8 @@ perf can be used to record and analyze trace of programs.
Execution can be recorded using 'perf record' with the cs_etm event,
specifying the name of the sink to record to, e.g:

+.. code:: console
+
perf record -e cs_etm/@20070000.etr/u --per-thread

The 'perf report' and 'perf script' commands can be used to analyze execution,
@@ -370,12 +394,16 @@ Generating coverage files for Feedback Directed Optimization: AutoFDO
'perf inject' accepts the --itrace option in which case tracing data is
removed and replaced with the synthesized events. e.g.

+.. code:: console
+
perf inject --itrace --strip -i perf.data -o perf.data.new

Below is an example of using ARM ETM for autoFDO. It requires autofdo
(https://github.com/google/autofdo) and gcc version 5. The bubble
sort example is from the AutoFDO tutorial (https://gcc.gnu.org/wiki/AutoFDO/Tutorial).

+.. code:: console
+
$ gcc-5 -O3 sort.c -o sort
$ taskset -c 2 ./sort
Bubble sorting array of 30000 elements
@@ -403,28 +431,36 @@ difference is that clients are driving the trace capture rather
than the program flow through the code.

As with any other CoreSight component, specifics about the STM tracer can be
-found in sysfs with more information on each entry being found in [1]:
+found in sysfs with more information on each entry being found in [#first]_:

-root@genericarmv8:~# ls /sys/bus/coresight/devices/20100000.stm
-enable_source hwevent_select port_enable subsystem uevent
-hwevent_enable mgmt port_select traceid
-root@genericarmv8:~#
+.. code:: console
+
+ root@genericarmv8:~# ls /sys/bus/coresight/devices/20100000.stm
+ enable_source hwevent_select port_enable subsystem uevent
+ hwevent_enable mgmt port_select traceid
+ root@genericarmv8:~#

Like any other source a sink needs to be identified and the STM enabled before
being used:

-root@genericarmv8:~# echo 1 > /sys/bus/coresight/devices/20010000.etf/enable_sink
-root@genericarmv8:~# echo 1 > /sys/bus/coresight/devices/20100000.stm/enable_source
+.. code:: console
+
+ root@genericarmv8:~# echo 1 > /sys/bus/coresight/devices/20010000.etf/enable_sink
+ root@genericarmv8:~# echo 1 > /sys/bus/coresight/devices/20100000.stm/enable_source

From there user space applications can request and use channels using the devfs
interface provided for that purpose by the generic STM API:

-root@genericarmv8:~# ls -l /dev/20100000.stm
-crw------- 1 root root 10, 61 Jan 3 18:11 /dev/20100000.stm
-root@genericarmv8:~#
+.. code:: console
+
+ root@genericarmv8:~# ls -l /dev/20100000.stm
+ crw------- 1 root root 10, 61 Jan 3 18:11 /dev/20100000.stm
+ root@genericarmv8:~#
+
+Details on how to use the generic STM API can be found here [#second]_.
+
+.. [#first] Documentation/ABI/testing/sysfs-bus-coresight-devices-stm

-Details on how to use the generic STM API can be found here [2].
+.. [#second] Documentation/trace/stm.rst

-[1]. Documentation/ABI/testing/sysfs-bus-coresight-devices-stm
-[2]. Documentation/trace/stm.rst
-[3]. https://github.com/Linaro/perf-opencsd
+.. [#third] https://github.com/Linaro/perf-opencsd
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index 6b4107cf4b98..3330c5456bcb 100644
--- a/Documentation/trace/index.rst
+++ b/Documentation/trace/index.rst
@@ -23,3 +23,4 @@ Linux Tracing Technologies
intel_th
stm
sys-t
+ coresight
--
2.11.0
\
 
 \ /
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