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Commit 1bbf6c88 authored by Rama Aparna Mallavarapu's avatar Rama Aparna Mallavarapu Committed by Gerrit - the friendly Code Review server
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coresight: add support to enable multiple coresight paths 



Current coresight implementation supports enabling of a
single path. This patch adds support to enable multiple source
to sink paths. We build a path from source to sink when any
source is enabled and store it in a list. When the source is
disabled, we fetch the corresponding path from the list and
decrement the refcount on each device in the path. The device
is disabled if the refcount reaches zero.

Change-Id: Idd3dcfd0346bdfd39f41ac13e8e53068907c14e4
Signed-off-by: default avatarSatyajit Desai <sadesai@codeaurora.org>
Signed-off-by: default avatarRama Aparna Mallavarapu <aparnam@codeaurora.org>
Signed-off-by: default avatarMulu He <muluhe@codeaurora.org>
parent 9aa6ee8b

drivers/hwtracing/coresight/coresight-etm-perf.c

+3 −1
Original line number Diff line number Diff line
@@ -111,6 +111,7 @@ static void free_event_data(struct work_struct *work) 
	cpumask_t *mask;

	struct etm_event_data *event_data;

	struct coresight_device *sink;

	struct coresight_device *source;



	event_data = container_of(work, struct etm_event_data, work);

	mask = &event_data->mask;
@@ -126,8 +127,9 @@ static void free_event_data(struct work_struct *work) 
	}



	for_each_cpu(cpu, mask) {

		source = coresight_get_source(event_data->path[cpu]);

		if (!(IS_ERR_OR_NULL(event_data->path[cpu])))

			coresight_release_path(event_data->path[cpu]);

			coresight_release_path(source, event_data->path[cpu]);

	}



	kfree(event_data->path);

drivers/hwtracing/coresight/coresight-priv.h

+3 −1
Original line number Diff line number Diff line
@@ -143,7 +143,9 @@ struct coresight_device *coresight_get_sink(struct list_head *path); 
struct coresight_device *coresight_get_enabled_sink(bool reset);

struct list_head *coresight_build_path(struct coresight_device *csdev,

				       struct coresight_device *sink);

void coresight_release_path(struct list_head *path);

struct coresight_device *coresight_get_source(struct list_head *path);

void coresight_release_path(struct coresight_device *csdev,

			    struct list_head *path);



#ifdef CONFIG_CORESIGHT_SOURCE_ETM3X

extern int etm_readl_cp14(u32 off, unsigned int *val);

drivers/hwtracing/coresight/coresight.c

+61 −53
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright (c) 2012, The Linux Foundation. All rights reserved.

 * Copyright (c) 2012, 2017, The Linux Foundation. All rights reserved.

 */



#include <linux/kernel.h>
@@ -33,18 +33,16 @@ struct coresight_node { 
};



/*

 * When operating Coresight drivers from the sysFS interface, only a single

 * path can exist from a tracer (associated to a CPU) to a sink.

 * struct coresight_path - path from source to sink

 * @path:	Address of path list.

 * @link:	hook to the list.

 */

static DEFINE_PER_CPU(struct list_head *, tracer_path);

struct coresight_path {

	struct list_head *path;

	struct list_head link;

};



/*

 * As of this writing only a single STM can be found in CS topologies.  Since

 * there is no way to know if we'll ever see more and what kind of

 * configuration they will enact, for the time being only define a single path

 * for STM.

 */

static struct list_head *stm_path;

static LIST_HEAD(cs_active_paths);



/*

 * When losing synchronisation a new barrier packet needs to be inserted at the
@@ -151,7 +149,7 @@ static void coresight_disable_sink(struct coresight_device *csdev) 
	if (atomic_dec_return(csdev->refcnt) == 0) {

		if (sink_ops(csdev)->disable) {

			sink_ops(csdev)->disable(csdev);

			csdev->enable = false;

			csdev->activated = false;

		}

	}

}
@@ -364,6 +362,20 @@ int coresight_enable_path(struct list_head *path, u32 mode) 
	goto out;

}



struct coresight_device *coresight_get_source(struct list_head *path)

{

	struct coresight_device *csdev;



	if (!path)

		return NULL;



	csdev = list_first_entry(path, struct coresight_node, link)->csdev;

	if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE)

		return NULL;



	return csdev;

}



struct coresight_device *coresight_get_sink(struct list_head *path)

{

	struct coresight_device *csdev;
@@ -543,15 +555,24 @@ struct list_head *coresight_build_path(struct coresight_device *source, 
/**

 * coresight_release_path - release a previously built path.

 * @path:	the path to release.

 * Remove coresight path entry from source device

 *

 * Go through all the elements of a path and 1) removed it from the list and

 * 2) free the memory allocated for each node.

 */

void coresight_release_path(struct list_head *path)

void coresight_release_path(struct coresight_device *csdev,

			    struct list_head *path)

{

	struct coresight_device *csdev;

	struct coresight_node *nd, *next;



	if (csdev != NULL && csdev->node != NULL) {

		/* Remove path entry from source device */

		list_del(&csdev->node->link);

		kfree(csdev->node);

		csdev->node = NULL;

	}



	/* Free the path */

	list_for_each_entry_safe(nd, next, path, link) {

		csdev = nd->csdev;
@@ -592,9 +613,25 @@ static int coresight_validate_source(struct coresight_device *csdev, 
	return 0;

}



int coresight_store_path(struct coresight_device *csdev, struct list_head *path)

{

	struct coresight_path *node;



	node = kzalloc(sizeof(struct coresight_path), GFP_KERNEL);

	if (!node)

		return -ENOMEM;



	node->path = path;

	list_add(&node->link, &cs_active_paths);



	csdev->node = node;



	return 0;

}



int coresight_enable(struct coresight_device *csdev)

{

	int cpu, ret = 0;

	int ret = 0;

	struct coresight_device *sink;

	struct list_head *path;

	enum coresight_dev_subtype_source subtype;
@@ -643,25 +680,9 @@ int coresight_enable(struct coresight_device *csdev) 
	if (ret)

		goto err_source;



	switch (subtype) {

	case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:

		/*

		 * When working from sysFS it is important to keep track

		 * of the paths that were created so that they can be

		 * undone in 'coresight_disable()'.  Since there can only

		 * be a single session per tracer (when working from sysFS)

		 * a per-cpu variable will do just fine.

		 */

		cpu = source_ops(csdev)->cpu_id(csdev);

		per_cpu(tracer_path, cpu) = path;

		break;

	case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:

		stm_path = path;

		break;

	default:

		/* We can't be here */

		break;

	}

	ret = coresight_store_path(csdev, path);

	if (ret)

		goto err_source;



out:

	mutex_unlock(&coresight_mutex);
@@ -671,15 +692,14 @@ int coresight_enable(struct coresight_device *csdev) 
	coresight_disable_path(path);



err_path:

	coresight_release_path(path);

	coresight_release_path(csdev, path);

	goto out;

}

EXPORT_SYMBOL_GPL(coresight_enable);



void coresight_disable(struct coresight_device *csdev)

{

	int cpu, ret;

	struct list_head *path = NULL;

	int  ret;



	mutex_lock(&coresight_mutex);
@@ -690,23 +710,11 @@ void coresight_disable(struct coresight_device *csdev) 
	if (!csdev->enable || !coresight_disable_source(csdev))

		goto out;



	switch (csdev->subtype.source_subtype) {

	case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:

		cpu = source_ops(csdev)->cpu_id(csdev);

		path = per_cpu(tracer_path, cpu);

		per_cpu(tracer_path, cpu) = NULL;

		break;

	case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:

		path = stm_path;

		stm_path = NULL;

		break;

	default:

		/* We can't be here */

		break;

	}

	if (csdev->node == NULL)

		goto out;



	coresight_disable_path(path);

	coresight_release_path(path);

	coresight_disable_path(csdev->node->path);

	coresight_release_path(csdev, csdev->node->path);



out:

	mutex_unlock(&coresight_mutex);

include/linux/coresight.h

+1 −0
Original line number Diff line number Diff line
@@ -171,6 +171,7 @@ struct coresight_device { 
	const struct coresight_ops *ops;

	struct device dev;

	atomic_t *refcnt;

	struct coresight_path *node;

	bool orphan;

	bool enable;	/* true only if configured as part of a path */

	bool activated;	/* true only if a sink is part of a path */