coresight: etm4x: Skip setting LPOVERRIDE bit for qcom, skip-power-up

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@vger.kernel.org
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20201127175256.1092685-2-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index abd706b..6096d7a 100644 (file)
--- 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;