linux-kernel - [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up

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Message-Id: <20201016101025.26505-1-saiprakash.ranjan@codeaurora.org>
Date:   Fri, 16 Oct 2020 15:40:25 +0530
From:   Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>
Cc:     coresight@...ts.linaro.org, Stephen Boyd <swboyd@...omium.org>,
        denik@...omium.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
Subject: [PATCH] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up

There is a bug on the systems supporting to skip power up
(qcom,skip-power-up) where setting LPOVERRIDE bit(low-power
state override behaviour) will result in CPU hangs/lockups
even on the implementations which supports it. So skip
setting the LPOVERRIDE bit for such platforms.

Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace unit power up")
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
---
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index abd706b216ac..6096d7abf80d 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -779,7 +779,7 @@ static void etm4_init_arch_data(void *info)
 	 * LPOVERRIDE, bit[23] implementation supports
 	 * low-power state override
 	 */
-	if (BMVAL(etmidr5, 23, 23))
+	if (BMVAL(etmidr5, 23, 23) && (!drvdata->skip_power_up))
 		drvdata->lpoverride = true;
 	else
 		drvdata->lpoverride = false;

base-commit: 3477326277451000bc667dfcc4fd0774c039184c
-- 
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