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authorLinus Torvalds <torvalds@linux-foundation.org>2016-05-20 21:20:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-20 21:20:31 -0700
commit5af2344013454640e0133bb62e8cf2e30190a472 (patch)
tree93495d1eb88d7498dac4747a3d28081c09a69a55 /Documentation/trace
parent19e36ad292ab24980db64a5ff17973d3118a8fb9 (diff)
parent725d0123dfff3d7b666cf57f5d29c50addfc99d3 (diff)
downloadop-kernel-dev-5af2344013454640e0133bb62e8cf2e30190a472.zip
op-kernel-dev-5af2344013454640e0133bb62e8cf2e30190a472.tar.gz
Merge tag 'char-misc-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char / misc driver updates from Greg KH: "Here's the big char and misc driver update for 4.7-rc1. Lots of different tiny driver subsystems have updates here with new drivers and functionality. Details in the shortlog. All have been in linux-next with no reported issues for a while" * tag 'char-misc-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (125 commits) mcb: Delete num_cells variable which is not required mcb: Fixed bar number assignment for the gdd mcb: Replace ioremap and request_region with the devm version mcb: Implement bus->dev.release callback mcb: export bus information via sysfs mcb: Correctly initialize the bus's device mei: bus: call mei_cl_read_start under device lock coresight: etb10: adjust read pointer only when needed coresight: configuring ETF in FIFO mode when acting as link coresight: tmc: implementing TMC-ETF AUX space API coresight: moving struct cs_buffers to header file coresight: tmc: keep track of memory width coresight: tmc: make sysFS and Perf mode mutually exclusive coresight: tmc: dump system memory content only when needed coresight: tmc: adding mode of operation for link/sinks coresight: tmc: getting rid of multiple read access coresight: tmc: allocating memory when needed coresight: tmc: making prepare/unprepare functions generic coresight: tmc: splitting driver in ETB/ETF and ETR components coresight: tmc: cleaning up header file ...
Diffstat (limited to 'Documentation/trace')
-rw-r--r--Documentation/trace/coresight.txt37
1 files changed, 35 insertions, 2 deletions
diff --git a/Documentation/trace/coresight.txt b/Documentation/trace/coresight.txt
index 0a5c329..a33c88c 100644
--- a/Documentation/trace/coresight.txt
+++ b/Documentation/trace/coresight.txt
@@ -190,8 +190,8 @@ expected to be accessed and controlled using those entries.
Last but not least, "struct module *owner" is expected to be set to reflect
the information carried in "THIS_MODULE".
-How to use
-----------
+How to use the tracer modules
+-----------------------------
Before trace collection can start, a coresight sink needs to be identify.
There is no limit on the amount of sinks (nor sources) that can be enabled at
@@ -297,3 +297,36 @@ Info Tracing enabled
Instruction 13570831 0x8026B584 E28DD00C false ADD sp,sp,#0xc
Instruction 0 0x8026B588 E8BD8000 true LDM sp!,{pc}
Timestamp Timestamp: 17107041535
+
+How to use the STM module
+-------------------------
+
+Using the System Trace Macrocell module is the same as the tracers - the only
+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]:
+
+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
+
+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:~#
+
+Details on how to use the generic STM API can be found here [2].
+
+[1]. Documentation/ABI/testing/sysfs-bus-coresight-devices-stm
+[2]. Documentation/trace/stm.txt
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