path: root/drivers/hwtracing/coresight/coresight.c

/* Copyright (c) 2012, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/clk.h>
#include <linux/coresight.h>
#include <linux/of_platform.h>
#include <linux/delay.h>
#include <linux/pm_runtime.h>

#include "coresight-priv.h"

static DEFINE_MUTEX(coresight_mutex);

/**
 * struct coresight_node - elements of a path, from source to sink
 * @csdev:	Address of an element.
 * @link:	hook to the list.
 */
struct coresight_node {
	struct coresight_device *csdev;
	struct list_head link;
};

/*
 * When operating Coresight drivers from the sysFS interface, only a single
 * path can exist from a tracer (associated to a CPU) to a sink.
 */
static DEFINE_PER_CPU(struct list_head *, tracer_path);

/*
 * 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 int coresight_id_match(struct device *dev, void *data)
{
	int trace_id, i_trace_id;
	struct coresight_device *csdev, *i_csdev;

	csdev = data;
	i_csdev = to_coresight_device(dev);

	/*
	 * No need to care about oneself and components that are not
	 * sources or not enabled
	 */
	if (i_csdev == csdev || !i_csdev->enable ||
	    i_csdev->type != CORESIGHT_DEV_TYPE_SOURCE)
		return 0;

	/* Get the source ID for both compoment */
	trace_id = source_ops(csdev)->trace_id(csdev);
	i_trace_id = source_ops(i_csdev)->trace_id(i_csdev);

	/* All you need is one */
	if (trace_id == i_trace_id)
		return 1;

	return 0;
}

static int coresight_source_is_unique(struct coresight_device *csdev)
{
	int trace_id = source_ops(csdev)->trace_id(csdev);

	/* this shouldn't happen */
	if (trace_id < 0)
		return 0;

	return !bus_for_each_dev(&coresight_bustype, NULL,
				 csdev, coresight_id_match);
}

static int coresight_find_link_inport(struct coresight_device *csdev,
				      struct coresight_device *parent)
{
	int i;
	struct coresight_connection *conn;

	for (i = 0; i < parent->nr_outport; i++) {
		conn = &parent->conns[i];
		if (conn->child_dev == csdev)
			return conn->child_port;
	}

	dev_err(&csdev->dev, "couldn't find inport, parent: %s, child: %s\n",
		dev_name(&parent->dev), dev_name(&csdev->dev));

	return 0;
}

static int coresight_find_link_outport(struct coresight_device *csdev,
				       struct coresight_device *child)
{
	int i;
	struct coresight_connection *conn;

	for (i = 0; i < csdev->nr_outport; i++) {
		conn = &csdev->conns[i];
		if (conn->child_dev == child)
			return conn->outport;
	}

	dev_err(&csdev->dev, "couldn't find outport, parent: %s, child: %s\n",
		dev_name(&csdev->dev), dev_name(&child->dev));

	return 0;
}

static int coresight_enable_sink(struct coresight_device *csdev, u32 mode)
{
	int ret;

	if (!csdev->enable) {
		if (sink_ops(csdev)->enable) {
			ret = sink_ops(csdev)->enable(csdev, mode);
			if (ret)
				return ret;
		}
		csdev->enable = true;
	}

	atomic_inc(csdev->refcnt);

	return 0;
}

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;
		}
	}
}

static int coresight_enable_link(struct coresight_device *csdev,
				 struct coresight_device *parent,
				 struct coresight_device *child)
{
	int ret;
	int link_subtype;
	int refport, inport, outport;

	if (!parent || !child)
		return -EINVAL;

	inport = coresight_find_link_inport(csdev, parent);
	outport = coresight_find_link_outport(csdev, child);
	link_subtype = csdev->subtype.link_subtype;

	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
		refport = inport;
	else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
		refport = outport;
	else
		refport = 0;

	if (atomic_inc_return(&csdev->refcnt[refport]) == 1) {
		if (link_ops(csdev)->enable) {
			ret = link_ops(