[PATCH] coresight-etm4x: add isb() before reading the TRCSTATR

[yuanfang zhang]

From: Yuanfang Zhang <quic_yuanfang at quicinc.com>

As recommended by section 4.3.7 ("Synchronization when using system
instructions to progrom the trace unit") of ARM IHI 0064H.b, the
self-hosted trace analyzer must perform a Context synchronization
event between writing to the TRCPRGCTLR and reading the TRCSTATR.

Signed-off-by: Yuanfang Zhang <quic_yuanfang at quicinc.com>
---
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 66d44a404ad0..5da2c523c30a 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -906,6 +906,7 @@ static void etm4_disable_hw(void *info)
 	tsb_csync();
 	etm4x_relaxed_write32(csa, control, TRCPRGCTLR);
 
+	isb();
 	/* wait for TRCSTATR.PMSTABLE to go to '1' */
 	if (coresight_timeout(csa, TRCSTATR, TRCSTATR_PMSTABLE_BIT, 1))
 		dev_err(etm_dev,
-- 
2.34.1