linux-kernel - [PATCH 5.10 19/40] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom, skip-power-up

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Date:   Wed, 23 Dec 2020 16:33:20 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Suzuki K Poulose <suzuki.poulose@....com>,
        Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>,
        Mathieu Poirier <mathieu.poirier@...aro.org>
Subject: [PATCH 5.10 19/40] coresight: etm4x: Skip setting LPOVERRIDE bit for qcom, skip-power-up

From: Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>

commit ac0f82b1b4956e348a6b2de8104308144ffb6ef7 upstream.

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")
Cc: stable@...r.kernel.org
Reviewed-by: Suzuki K Poulose <suzuki.poulose@....com>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
Link: https://lore.kernel.org/r/20201127175256.1092685-2-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/hwtracing/coresight/coresight-etm4x-core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- 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 *in
 	 * 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;