linux-kernel - [PATCH v3 2/2] coresight: etm4x: docs: Add documentation for 'ts

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Date:   Tue, 23 Aug 2022 17:06:50 +0100
From:   James Clark <james.clark@....com>
To:     suzuki.poulose@....com, coresight@...ts.linaro.org,
        mathieu.poirier@...aro.org
Cc:     mike.leach@...aro.org, leo.yan@...aro.org,
        linux-kernel@...r.kernel.org, german.gomez@....com,
        James Clark <james.clark@....com>,
        Jonathan Corbet <corbet@....net>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        linux-arm-kernel@...ts.infradead.org, linux-doc@...r.kernel.org
Subject: [PATCH v3 2/2] coresight: etm4x: docs: Add documentation for 'ts_source' sysfs interface

From: German Gomez <german.gomez@....com>

Sync sysfs documentation pages to include the new ts_source (timestamp
source) interface.

Signed-off-by: German Gomez <german.gomez@....com>
Signed-off-by: James Clark <james.clark@....com>
---
 .../ABI/testing/sysfs-bus-coresight-devices-etm4x  |  8 ++++++++
 .../trace/coresight/coresight-etm4x-reference.rst  | 14 ++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
index 8e53a32f8150..08b1964f27d3 100644
--- a/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
+++ b/Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x
@@ -516,3 +516,11 @@ Contact:	Mathieu Poirier <mathieu.poirier@...aro.org>
 Description:	(Read) Returns the number of special conditional P1 right-hand keys
 		that the trace unit can use (0x194).  The value is taken
 		directly from the HW.
+
+What:		/sys/bus/coresight/devices/etm<N>/ts_source
+Date:		October 2022
+KernelVersion:	6.1
+Contact:	Mathieu Poirier <mathieu.poirier@...aro.org> or Suzuki K Poulose <suzuki.poulose@....com>
+Description:	(Read) When FEAT_TRF is implemented, value of TRFCR_ELx.TS used for
+		trace session. Otherwise -1 indicates an unknown time source. Check
+		trcidr0.tssize to see if a global timestamp is available.
diff --git a/Documentation/trace/coresight/coresight-etm4x-reference.rst b/Documentation/trace/coresight/coresight-etm4x-reference.rst
index fb7578fd9372..70e34b8c81c1 100644
--- a/Documentation/trace/coresight/coresight-etm4x-reference.rst
+++ b/Documentation/trace/coresight/coresight-etm4x-reference.rst
@@ -71,6 +71,20 @@
 
 ----
 
+:File:            ``ts_source`` (ro)
+:Trace Registers: None.
+:Notes:
+    When FEAT_TRF is implemented, value of TRFCR_ELx.TS used for trace session. Otherwise -1
+    indicates an unknown time source. Check trcidr0.tssize to see if a global timestamp is
+    available.
+
+:Example:
+    ``$> cat ts_source``
+
+    ``$> 1``
+
+----
+
 :File:            ``addr_idx`` (rw)
 :Trace Registers: None.
 :Notes:
-- 
2.28.0