[PATCHv3 1/2] coresight: replicator: Reset replicator if context is lost

Sai Prakash Ranjan
2020-05-22T18:37:22Z

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. So add a new property "qcom,replicator-loses-context"
to identify such replicators and reset them.

Suggested-by: Mike Leach <mike.leach@linaro.org>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
---
.../coresight/coresight-replicator.c | 55 +++++++++++++------
1 file changed, 38 insertions(+), 17 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
index e7dc1c31d20d..9d3a8f915784 100644
--- a/drivers/hwtracing/coresight/coresight-replicator.c
+++ b/drivers/hwtracing/coresight/coresight-replicator.c
@@ -14,6 +14,7 @@
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>
+#include <linux/property.h>
#include <linux/clk.h>
#include <linux/of.h>
#include <linux/coresight.h>
@@ -32,12 +33,14 @@ DEFINE_CORESIGHT_DEVLIST(replicator_devs, "replicator");
* @atclk: optional clock for the core parts of the replicator.
* @csdev: component vitals needed by the framework
* @spinlock: serialize enable/disable operations.
+ * @check_idfilter_val: check if the context is lost upon clock removal.
*/
struct replicator_drvdata {
void __iomem *base;
struct clk *atclk;
struct coresight_device *csdev;
spinlock_t spinlock;
+ bool check_idfilter_val;
};

static void dynamic_replicator_reset(struct replicator_drvdata *drvdata)
@@ -66,29 +69,43 @@ static int dynamic_replicator_enable(struct replicator_drvdata *drvdata,
int inport, int outport)
{
int rc = 0;
- u32 reg;
-
- switch (outport) {
- case 0:
- reg = REPLICATOR_IDFILTER0;
- break;
- case 1:
- reg = REPLICATOR_IDFILTER1;
- break;
- default:
- WARN_ON(1);
- return -EINVAL;
- }
+ u32 id0val, id1val;

CS_UNLOCK(drvdata->base);

- if ((readl_relaxed(drvdata->base + REPLICATOR_IDFILTER0) == 0xff) &&
- (readl_relaxed(drvdata->base + REPLICATOR_IDFILTER1) == 0xff))
+ id0val = readl_relaxed(drvdata->base + REPLICATOR_IDFILTER0);
+ id1val = readl_relaxed(drvdata->base + REPLICATOR_IDFILTER1);
+
+ /*
+ * Some replicator designs lose context when AMBA clocks are removed,
+ * so have a check for this.
+ */
+ if (drvdata->check_idfilter_val && id0val == 0x0 && id1val == 0x0)
+ id0val = id1val = 0xff;
+
+ if (id0val == 0xff && id1val == 0xff)
rc = coresight_claim_device_unlocked(drvdata->base);

+ if (!rc) {
+ switch (outport) {
+ case 0:
+ id0val = 0x0;
+ break;
+ case 1:
+ id1val = 0x0;
+ break;
+ default:
+ WARN_ON(1);
+ rc = -EINVAL;
+ }
+ }
+
/* Ensure that the outport is enabled. */
- if (!rc)
- writel_relaxed(0x00, drvdata->base + reg);
+ if (!rc) {
+ writel_relaxed(id0val, drvdata->base + REPLICATOR_IDFILTER0);
+ writel_relaxed(id1val, drvdata->base + REPLICATOR_IDFILTER1);
+ }
+
CS_LOCK(drvdata->base);

return rc;
@@ -239,6 +256,10 @@ static int replicator_probe(struct device *dev, struct resource *res)
desc.groups = replicator_groups;
}

+ if (fwnode_property_present(dev_fwnode(dev),
+ "qcom,replicator-loses-context"))
+ drvdata->check_idfilter_val = true;
+
dev_set_drvdata(dev, drvdata);

pdata = coresight_get_platform_data(dev);
--
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