[PATCH] coresight: replicator: Reset replicator if context is lost

From: Sai Prakash Ranjan
Date: Mon May 11 2020 - 04:34:41 EST


On some QCOM SoCs, replicators in Always-On domain loses its
context as soon as the clock is disabled. Currently as a part
of pm_runtime workqueue, clock is disabled after the replicator
is initialized by amba_pm_runtime_suspend assuming that context
is not lost which is not true for replicators with such
limitations. Hence check the replicator idfilter registers
in dynamic_replicator_enable() and reset again.

Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
---

More info here - https://lore.kernel.org/patchwork/patch/1231182/

---
drivers/hwtracing/coresight/coresight-replicator.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
index e7dc1c31d20d..11df63f51071 100644
--- a/drivers/hwtracing/coresight/coresight-replicator.c
+++ b/drivers/hwtracing/coresight/coresight-replicator.c
@@ -68,6 +68,17 @@ static int dynamic_replicator_enable(struct replicator_drvdata *drvdata,
int rc = 0;
u32 reg;

+ /*
+ * On some QCOM SoCs with replicators in Always-On domain, disabling
+ * clock will result in replicator losing its context. Currently
+ * as a part of pm_runtime workqueue, amba_pm_runtime_suspend disables
+ * clock assuming the context is not lost which is not true for cases
+ * with hardware limitations as the above.
+ */
+ if ((readl_relaxed(drvdata->base + REPLICATOR_IDFILTER0) == 0) &&
+ (readl_relaxed(drvdata->base + REPLICATOR_IDFILTER1) == 0))
+ dynamic_replicator_reset(drvdata);
+
switch (outport) {
case 0:
reg = REPLICATOR_IDFILTER0;
--
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