Commit 9edf2910 authored by Mike Leach's avatar Mike Leach Committed by Suzuki K Poulose
Browse files

coresight: etm3x: Update ETM3 driver to use Trace ID API 



Use the TraceID API to allocate ETM trace IDs dynamically.

As with the etm4x we allocate on enable / disable for perf,
allocate on enable / reset for sysfs.

Additionally we allocate on sysfs file read as both perf and sysfs
can read the ID before enabling the hardware.

Remove sysfs option to write trace ID - which is inconsistent with
both the dynamic allocation method and the fixed allocation method
previously used.

Signed-off-by: default avatarMike Leach <mike.leach@linaro.org>
Reviewed-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230116124928.5440-7-mike.leach@linaro.org
parent df487120

Documentation/ABI/testing/sysfs-bus-coresight-devices-etm3x

+1 −1
Original line number Diff line number Diff line
@@ -236,7 +236,7 @@ What: /sys/bus/coresight/devices/<memory_map>.[etm|ptm]/traceid 
Date:		November 2014

KernelVersion:	3.19

Contact:	Mathieu Poirier <mathieu.poirier@linaro.org>

Description: 	(RW) Holds the trace ID that will appear in the trace stream

Description: 	(RO) Holds the trace ID that will appear in the trace stream

		coming from this trace entity.



What:		/sys/bus/coresight/devices/<memory_map>.[etm|ptm]/trigger_event

drivers/hwtracing/coresight/coresight-etm.h

+2 −0
Original line number Diff line number Diff line
@@ -287,4 +287,6 @@ int etm_get_trace_id(struct etm_drvdata *drvdata); 
void etm_set_default(struct etm_config *config);

void etm_config_trace_mode(struct etm_config *config);

struct etm_config *get_etm_config(struct etm_drvdata *drvdata);

int etm_read_alloc_trace_id(struct etm_drvdata *drvdata);

void etm_release_trace_id(struct etm_drvdata *drvdata);

#endif

drivers/hwtracing/coresight/coresight-etm3x-core.c

+66 −6
Original line number Diff line number Diff line
@@ -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
@@ -490,16 +491,59 @@ static int etm_trace_id(struct coresight_device *csdev) 
	return etm_get_trace_id(drvdata);

}



int etm_read_alloc_trace_id(struct etm_drvdata *drvdata)

{

	int trace_id;



	/*

	 * 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;

}



void etm_release_trace_id(struct etm_drvdata *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 +556,11 @@ 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 +577,10 @@ 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 +664,12 @@ 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 +694,13 @@ 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");

}
@@ -781,11 +847,6 @@ 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 +932,6 @@ 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);

drivers/hwtracing/coresight/coresight-etm3x-sysfs.c

+7 −20
Original line number Diff line number Diff line
@@ -85,6 +85,7 @@ static ssize_t reset_store(struct device *dev, 
		}



		etm_set_default(config);

		etm_release_trace_id(drvdata);

		spin_unlock(&drvdata->spinlock);

	}
@@ -1189,30 +1190,16 @@ static DEVICE_ATTR_RO(cpu); 
static ssize_t traceid_show(struct device *dev,

			    struct device_attribute *attr, char *buf)

{

	unsigned long val;

	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);



	val = etm_get_trace_id(drvdata);



	return sprintf(buf, "%#lx\n", val);

}



static ssize_t traceid_store(struct device *dev,

			     struct device_attribute *attr,

			     const char *buf, size_t size)

{

	int ret;

	unsigned long val;

	int trace_id;

	struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);



	ret = kstrtoul(buf, 16, &val);

	if (ret)

		return ret;

	trace_id = etm_read_alloc_trace_id(drvdata);

	if (trace_id < 0)

		return trace_id;



	drvdata->traceid = val & ETM_TRACEID_MASK;

	return size;

	return sysfs_emit(buf, "%#x\n", trace_id);

}

static DEVICE_ATTR_RW(traceid);

static DEVICE_ATTR_RO(traceid);



static struct attribute *coresight_etm_attrs[] = {

	&dev_attr_nr_addr_cmp.attr,