linux-kernel - [PATCH 2/2] Coresight: Set correct cs_mode for dummy source to fix disable issue

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Date: Wed, 26 Jun 2024 10:25:37 +0800
From: Jie Gan <quic_jiegan@...cinc.com>
To: Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suzuki K Poulose
	<suzuki.poulose@....com>,
        Alexander Shishkin
	<alexander.shishkin@...ux.intel.com>,
        Konrad Dybcio <konradybcio@...il.com>,
        Mike Leach <mike.leach@...aro.org>, Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
CC: Jinlong Mao <quic_jinlmao@...cinc.com>,
        Greg Kroah-Hartman
	<gregkh@...uxfoundation.org>,
        <coresight@...ts.linaro.org>, <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        Tingwei Zhang <quic_tingweiz@...cinc.com>,
        Yuanfang Zhang <quic_yuanfang@...cinc.com>,
        Tao Zhang
	<quic_taozha@...cinc.com>,
        Trilok Soni <quic_tsoni@...cinc.com>,
        Song Chai
	<quic_songchai@...cinc.com>,
        <linux-arm-msm@...r.kernel.org>, <andersson@...nel.org>,
        <quic_yijiyang@...cinc.com>, <quic_yuanjiey@...cinc.com>,
        <quic_liuxin@...cinc.com>, <quic_yanzl@...cinc.com>,
        <quic_xinlon@...cinc.com>, <quic_xueqnie@...cinc.com>,
        <quic_sijiwu@...cinc.com>
Subject: [PATCH 2/2] Coresight: Set correct cs_mode for dummy source to fix disable issue

The coresight_disable_source_sysfs function should verify the
mode of the coresight device before disabling the source.
However, the mode for the dummy source device is always set to
CS_MODE_DISABLED, resulting in the check consistently failing.
As a result, dummy source cannot be properly disabled.

Configure CS_MODE_SYSFS/CS_MODE_PERF during the enablement.
Configure CS_MODE_DISABLED during the disablement.

Fixes: 9d3ba0b6c056 ("Coresight: Add coresight dummy driver")
Signed-off-by: Jie Gan <quic_jiegan@...cinc.com>
---
 drivers/hwtracing/coresight/coresight-dummy.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-dummy.c b/drivers/hwtracing/coresight/coresight-dummy.c
index ac70c0b491be..dab389a5507c 100644
--- a/drivers/hwtracing/coresight/coresight-dummy.c
+++ b/drivers/hwtracing/coresight/coresight-dummy.c
@@ -23,6 +23,9 @@ DEFINE_CORESIGHT_DEVLIST(sink_devs, "dummy_sink");
 static int dummy_source_enable(struct coresight_device *csdev,
 			       struct perf_event *event, enum cs_mode mode)
 {
+	if (!coresight_take_mode(csdev, mode))
+		return -EBUSY;
+
 	dev_dbg(csdev->dev.parent, "Dummy source enabled\n");
 
 	return 0;
@@ -31,6 +34,7 @@ static int dummy_source_enable(struct coresight_device *csdev,
 static void dummy_source_disable(struct coresight_device *csdev,
 				 struct perf_event *event)
 {
+	coresight_set_mode(csdev, CS_MODE_DISABLED);
 	dev_dbg(csdev->dev.parent, "Dummy source disabled\n");
 }
 
-- 
2.34.1