summaryrefslogtreecommitdiff
path: root/Documentation
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-bus-coresight-devices-stm53
-rw-r--r--Documentation/trace/coresight.txt37
2 files changed, 88 insertions, 2 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-stm b/Documentation/ABI/testing/sysfs-bus-coresight-devices-stm
new file mode 100644
index 000000000000..1dffabe7f48d
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-stm
@@ -0,0 +1,53 @@
+What: /sys/bus/coresight/devices/<memory_map>.stm/enable_source
+Date: April 2016
+KernelVersion: 4.7
+Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
+Description: (RW) Enable/disable tracing on this specific trace macrocell.
+ Enabling the trace macrocell implies it has been configured
+ properly and a sink has been identified for it. The path
+ of coresight components linking the source to the sink is
+ configured and managed automatically by the coresight framework.
+
+What: /sys/bus/coresight/devices/<memory_map>.stm/hwevent_enable
+Date: April 2016
+KernelVersion: 4.7
+Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
+Description: (RW) Provides access to the HW event enable register, used in
+ conjunction with HW event bank select register.
+
+What: /sys/bus/coresight/devices/<memory_map>.stm/hwevent_select
+Date: April 2016
+KernelVersion: 4.7
+Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
+Description: (RW) Gives access to the HW event block select register
+ (STMHEBSR) in order to configure up to 256 channels. Used in
+ conjunction with "hwevent_enable" register as described above.
+
+What: /sys/bus/coresight/devices/<memory_map>.stm/port_enable
+Date: April 2016
+KernelVersion: 4.7
+Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
+Description: (RW) Provides access to the stimulus port enable register
+ (STMSPER). Used in conjunction with "port_select" described
+ below.
+
+What: /sys/bus/coresight/devices/<memory_map>.stm/port_select
+Date: April 2016
+KernelVersion: 4.7
+Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
+Description: (RW) Used to determine which bank of stimulus port bit in
+ register STMSPER (see above) apply to.
+
+What: /sys/bus/coresight/devices/<memory_map>.stm/status
+Date: April 2016
+KernelVersion: 4.7
+Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
+Description: (R) List various control and status registers. The specific
+ layout and content is driver specific.
+
+What: /sys/bus/coresight/devices/<memory_map>.stm/traceid
+Date: April 2016
+KernelVersion: 4.7
+Contact: Mathieu Poirier <mathieu.poirier@linaro.org>
+Description: (RW) Holds the trace ID that will appear in the trace stream
+ coming from this trace entity.
diff --git a/Documentation/trace/coresight.txt b/Documentation/trace/coresight.txt
index 0a5c3290e732..a33c88cd5d1d 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