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-rw-r--r--drivers/hwtracing/coresight/coresight-etm4x.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index 7ad15651e069..ec9468880c71 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -188,6 +188,13 @@ static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
dev_err(etm_dev,
"timeout while waiting for Idle Trace Status\n");
+ /*
+ * As recommended by section 4.3.7 ("Synchronization when using the
+ * memory-mapped interface") of ARM IHI 0064D
+ */
+ dsb(sy);
+ isb();
+
done:
CS_LOCK(drvdata->base);
@@ -453,8 +460,12 @@ static void etm4_disable_hw(void *info)
/* EN, bit[0] Trace unit enable bit */
control &= ~0x1;
- /* make sure everything completes before disabling */
- mb();
+ /*
+ * Make sure everything completes before disabling, as recommended
+ * by section 7.3.77 ("TRCVICTLR, ViewInst Main Control Register,
+ * SSTATUS") of ARM IHI 0064D
+ */
+ dsb(sy);
isb();
writel_relaxed(control, drvdata->base + TRCPRGCTLR);