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From:   Mathieu Poirier <mathieu.poirier@linaro.org>
To:     gregkh@linuxfoundation.org
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH 01/15] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom,skip-power-up
Date:   Fri, 27 Nov 2020 10:52:42 -0700
Message-Id: <20201127175256.1092685-2-mathieu.poirier@linaro.org>
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From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>

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.

Cc: stable@vger.kernel.org
Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace unit power up")
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.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;
-- 
2.25.1