linux-kernel - [PATCH 40/44] coresight: dynamic-replicator: Claim device for use

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Date:   Thu, 20 Sep 2018 13:18:15 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     gregkh@...uxfoundation.org
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH 40/44] coresight: dynamic-replicator: Claim device for use

From: Suzuki K Poulose <suzuki.poulose@....com>

Use CLAIM protocol to make sure the device is available for use.

Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
---
 .../coresight/coresight-dynamic-replicator.c       | 23 +++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-dynamic-replicator.c b/drivers/hwtracing/coresight/coresight-dynamic-replicator.c
index 97f4673452cb..299667b887fc 100644
--- a/drivers/hwtracing/coresight/coresight-dynamic-replicator.c
+++ b/drivers/hwtracing/coresight/coresight-dynamic-replicator.c
@@ -41,8 +41,11 @@ static void replicator_reset(struct replicator_state *drvdata)
 {
 	CS_UNLOCK(drvdata->base);
 
-	writel_relaxed(0xff, drvdata->base + REPLICATOR_IDFILTER0);
-	writel_relaxed(0xff, drvdata->base + REPLICATOR_IDFILTER1);
+	if (!coresight_claim_device_unlocked(drvdata->base)) {
+		writel_relaxed(0xff, drvdata->base + REPLICATOR_IDFILTER0);
+		writel_relaxed(0xff, drvdata->base + REPLICATOR_IDFILTER1);
+		coresight_disclaim_device_unlocked(drvdata->base);
+	}
 
 	CS_LOCK(drvdata->base);
 }
@@ -50,6 +53,7 @@ static void replicator_reset(struct replicator_state *drvdata)
 static int replicator_enable(struct coresight_device *csdev, int inport,
 			      int outport)
 {
+	int rc = 0;
 	u32 reg;
 	struct replicator_state *drvdata = dev_get_drvdata(csdev->dev.parent);
 
@@ -67,13 +71,19 @@ static int replicator_enable(struct coresight_device *csdev, int inport,
 
 	CS_UNLOCK(drvdata->base);
 
+	if ((readl_relaxed(drvdata->base + REPLICATOR_IDFILTER0) == 0xff) &&
+	    (readl_relaxed(drvdata->base + REPLICATOR_IDFILTER1) == 0xff))
+		rc = coresight_claim_device_unlocked(drvdata->base);
 
 	/* Ensure that the outport is enabled. */
-	writel_relaxed(0x00, drvdata->base + reg);
+	if (!rc) {
+		writel_relaxed(0x00, drvdata->base + reg);
+		dev_dbg(drvdata->dev, "REPLICATOR enabled\n");
+	}
+
 	CS_LOCK(drvdata->base);
 
-	dev_dbg(drvdata->dev, "REPLICATOR enabled\n");
-	return 0;
+	return rc;
 }
 
 static void replicator_disable(struct coresight_device *csdev, int inport,
@@ -99,6 +109,9 @@ static void replicator_disable(struct coresight_device *csdev, int inport,
 	/* disable the flow of ATB data through port */
 	writel_relaxed(0xff, drvdata->base + reg);
 
+	if ((readl_relaxed(drvdata->base + REPLICATOR_IDFILTER0) == 0xff) &&
+	    (readl_relaxed(drvdata->base + REPLICATOR_IDFILTER1) == 0xff))
+		coresight_disclaim_device_unlocked(drvdata->base);
 	CS_LOCK(drvdata->base);
 
 	dev_dbg(drvdata->dev, "REPLICATOR disabled\n");
-- 
2.7.4