1 files changed, 58 insertions, 35 deletions

diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index d0ab9933472b..afc57195ee52 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -32,6 +32,7 @@
 
 #include "coresight-etm.h"
 #include "coresight-etm-perf.h"
+#include "coresight-trace-id.h"
 
 /*
  * Not really modular but using module_param is the easiest way to
@@ -454,52 +455,59 @@ static int etm_cpu_id(struct coresight_device *csdev)
 	return drvdata->cpu;
 }
 
-int etm_get_trace_id(struct etm_drvdata *drvdata)
+int etm_read_alloc_trace_id(struct etm_drvdata *drvdata)
 {
-	unsigned long flags;
-	int trace_id = -1;
-	struct device *etm_dev;
+	int trace_id;
 
-	if (!drvdata)
-		goto out;
-
-	etm_dev = drvdata->csdev->dev.parent;
-	if (!local_read(&drvdata->mode))
-		return drvdata->traceid;
-
-	pm_runtime_get_sync(etm_dev);
-
-	spin_lock_irqsave(&drvdata->spinlock, flags);
-
-	CS_UNLOCK(drvdata->base);
-	trace_id = (etm_readl(drvdata, ETMTRACEIDR) & ETM_TRACEID_MASK);
-	CS_LOCK(drvdata->base);
-
-	spin_unlock_irqrestore(&drvdata->spinlock, flags);
-	pm_runtime_put(etm_dev);
-
-out:
+	/*
+	 * This will allocate a trace ID to the cpu,
+	 * or return the one currently allocated.
+	 *
+	 * trace id function has its own lock
+	 */
+	trace_id = coresight_trace_id_get_cpu_id(drvdata->cpu);
+	if (IS_VALID_CS_TRACE_ID(trace_id))
+		drvdata->traceid = (u8)trace_id;
+	else
+		dev_err(&drvdata->csdev->dev,
+			"Failed to allocate trace ID for %s on CPU%d\n",
+			dev_name(&drvdata->csdev->dev), drvdata->cpu);
 	return trace_id;
-
 }
 
-static int etm_trace_id(struct coresight_device *csdev)
+void etm_release_trace_id(struct etm_drvdata *drvdata)
 {
-	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
-
-	return etm_get_trace_id(drvdata);
+	coresight_trace_id_put_cpu_id(drvdata->cpu);
 }
 
 static int etm_enable_perf(struct coresight_device *csdev,
 			   struct perf_event *event)
 {
 	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	int trace_id;
 
 	if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id()))
 		return -EINVAL;
 
 	/* Configure the tracer based on the session's specifics */
 	etm_parse_event_config(drvdata, event);
+
+	/*
+	 * perf allocates cpu ids as part of _setup_aux() - device needs to use
+	 * the allocated ID. This reads the current version without allocation.
+	 *
+	 * This does not use the trace id lock to prevent lock_dep issues
+	 * with perf locks - we know the ID cannot change until perf shuts down
+	 * the session
+	 */
+	trace_id = coresight_trace_id_read_cpu_id(drvdata->cpu);
+	if (!IS_VALID_CS_TRACE_ID(trace_id)) {
+		dev_err(&drvdata->csdev->dev, "Failed to set trace ID for %s on CPU%d\n",
+			dev_name(&drvdata->csdev->dev), drvdata->cpu);
+		return -EINVAL;
+	}
+	drvdata->traceid = (u8)trace_id;
+
 	/* And enable it */
 	return etm_enable_hw(drvdata);
 }
@@ -512,6 +520,11 @@ static int etm_enable_sysfs(struct coresight_device *csdev)
 
 	spin_lock(&drvdata->spinlock);
 
+	/* sysfs needs to allocate and set a trace ID */
+	ret = etm_read_alloc_trace_id(drvdata);
+	if (ret < 0)
+		goto unlock_enable_sysfs;
+
 	/*
 	 * Configure the ETM only if the CPU is online.  If it isn't online
 	 * hw configuration will take place on the local CPU during bring up.
@@ -528,6 +541,10 @@ static int etm_enable_sysfs(struct coresight_device *csdev)
 		ret = -ENODEV;
 	}
 
+	if (ret)
+		etm_release_trace_id(drvdata);
+
+unlock_enable_sysfs:
 	spin_unlock(&drvdata->spinlock);
 
 	if (!ret)
@@ -611,6 +628,12 @@ static void etm_disable_perf(struct coresight_device *csdev)
 	coresight_disclaim_device_unlocked(csdev);
 
 	CS_LOCK(drvdata->base);
+
+	/*
+	 * perf will release trace ids when _free_aux()
+	 * is called at the end of the session
+	 */
+
 }
 
 static void etm_disable_sysfs(struct coresight_device *csdev)
@@ -635,6 +658,13 @@ static void etm_disable_sysfs(struct coresight_device *csdev)
 	spin_unlock(&drvdata->spinlock);
 	cpus_read_unlock();
 
+	/*
+	 * we only release trace IDs when resetting sysfs.
+	 * This permits sysfs users to read the trace ID after the trace
+	 * session has completed. This maintains operational behaviour with
+	 * prior trace id allocation method
+	 */
+
 	dev_dbg(&csdev->dev, "ETM tracing disabled\n");
 }
 
@@ -671,7 +701,6 @@ static void etm_disable(struct coresight_device *csdev,
 
 static const struct coresight_ops_source etm_source_ops = {
 	.cpu_id		= etm_cpu_id,
-	.trace_id	= etm_trace_id,
 	.enable		= etm_enable,
 	.disable	= etm_disable,
 };
@@ -781,11 +810,6 @@ static void etm_init_arch_data(void *info)
 	CS_LOCK(drvdata->base);
 }
 
-static void etm_init_trace_id(struct etm_drvdata *drvdata)
-{
-	drvdata->traceid = coresight_get_trace_id(drvdata->cpu);
-}
-
 static int __init etm_hp_setup(void)
 {
 	int ret;
@@ -871,7 +895,6 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id)
 	if (etm_arch_supported(drvdata->arch) == false)
 		return -EINVAL;
 
-	etm_init_trace_id(drvdata);
 	etm_set_default(&drvdata->config);
 
 	pdata = coresight_get_platform_data(dev);