linux-kernel - [PATCH] coresight: tmc: fix failure to disable/enable ETF after reading

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Message-Id: <20250423103744.475-1-jie.gan@oss.qualcomm.com>
Date: Wed, 23 Apr 2025 18:37:44 +0800
From: Jie Gan <jie.gan@....qualcomm.com>
To: Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>,
        James Clark <james.clark@...aro.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Yabin Cui <yabinc@...gle.com>
Cc: Tingwei Zhang <quic_tingweiz@...cinc.com>, coresight@...ts.linaro.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Yuanfang Zhang <quic_yuanfang@...cinc.com>
Subject: [PATCH] coresight: tmc: fix failure to disable/enable ETF after reading

From: Mao Jinlong <quic_jinlmao@...cinc.com>

From: Mao Jinlong <quic_jinlmao@...cinc.com>

ETF may fail to re-enable after reading, and driver->reading will
not be set to false, this will cause failure to enable/disable to ETF.
This change set driver->reading to false even if re-enabling fail.

Fixes: 669c4614236a7 ("coresight: tmc: Don't enable TMC when it's not ready.")
Co-developed-by: Yuanfang Zhang <quic_yuanfang@...cinc.com>
Signed-off-by: Yuanfang Zhang <quic_yuanfang@...cinc.com>
Signed-off-by: Mao Jinlong <quic_jinlmao@...cinc.com>
Signed-off-by: Jie Gan <jie.gan@....qualcomm.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etf.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index d858740001c2..8c9f14e36bc2 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -87,6 +87,12 @@ static void __tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
 {
 	CS_UNLOCK(drvdata->base);
 
+	/* Check if the etf already disabled*/
+	if (!(readl_relaxed(drvdata->base + TMC_CTL) & TMC_CTL_CAPT_EN)) {
+		CS_LOCK(drvdata->base);
+		return;
+	}
+
 	tmc_flush_and_stop(drvdata);
 	/*
 	 * When operating in sysFS mode the content of the buffer needs to be
@@ -747,7 +753,6 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
 	char *buf = NULL;
 	enum tmc_mode mode;
 	unsigned long flags;
-	int rc = 0;
 
 	/* config types are set a boot time and never change */
 	if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETB &&
@@ -773,11 +778,7 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
 		 * can't be NULL.
 		 */
 		memset(drvdata->buf, 0, drvdata->size);
-		rc = __tmc_etb_enable_hw(drvdata);
-		if (rc) {
-			raw_spin_unlock_irqrestore(&drvdata->spinlock, flags);
-			return rc;
-		}
+		__tmc_etb_enable_hw(drvdata);
 	} else {
 		/*
 		 * The ETB/ETF is not tracing and the buffer was just read.
-- 
2.34.1