coresight: replicator: Reset replicator if context is lost

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>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200716175746.3338735-6-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
index c619b456f55acc73e37ad5e41bcb80b3f3129853..78acf29c49ca9c7c9b7221be074cf7d6c57b7e77 100644 (file)
--- 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);