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

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2020 Linaro Limited, All rights reserved.
 * Author: Mike Leach <mike.leach@linaro.org>
 */

#include <linux/platform_device.h>
#include <linux/slab.h>

#include "coresight-config.h"
#include "coresight-etm-perf.h"
#include "coresight-syscfg.h"
#include "coresight-syscfg-configfs.h"

/*
 * cscfg_ API manages configurations and features for the entire coresight
 * infrastructure.
 *
 * It allows the loading of configurations and features, and loads these into
 * coresight devices as appropriate.
 */

/* protect the cscsg_data and device */
static DEFINE_MUTEX(cscfg_mutex);

/* only one of these */
static struct cscfg_manager *cscfg_mgr;

/* load features and configuations into the lists */

/* get name feature instance from a coresight device list of features */
static struct cscfg_feature_csdev *
cscfg_get_feat_csdev(struct coresight_device *csdev, const char *name)
{
	struct cscfg_feature_csdev *feat_csdev = NULL;

	list_for_each_entry(feat_csdev, &csdev->feature_csdev_list, node) {
		if (strcmp(feat_csdev->feat_desc->name, name) == 0)
			return feat_csdev;
	}
	return NULL;
}

/* allocate the device config instance - with max number of used features */
static struct cscfg_config_csdev *
cscfg_alloc_csdev_cfg(struct coresight_device *csdev, int nr_feats)
{
	struct cscfg_config_csdev *config_csdev = NULL;
	struct device *dev = csdev->dev.parent;

	/* this is being allocated using the devm for the coresight device */
	config_csdev = devm_kzalloc(dev,
				    offsetof(struct cscfg_config_csdev, feats_csdev[nr_feats]),
				    GFP_KERNEL);
	if (!config_csdev)
		return NULL;

	config_csdev->csdev = csdev;
	return config_csdev;
}

/* Load a config into a device if there are any feature matches between config and device */
static int cscfg_add_csdev_cfg(struct coresight_device *csdev,
			       struct cscfg_config_desc *config_desc)
{
	struct cscfg_config_csdev *config_csdev = NULL;
	struct cscfg_feature_csdev *feat_csdev;
	unsigned long flags;
	int i;

	/* look at each required feature and see if it matches any feature on the device */
	for (i = 0; i < config_desc->nr_feat_refs; i++) {
		/* look for a matching name */
		feat_csdev = cscfg_get_feat_csdev(csdev, config_desc->feat_ref_names[i]);
		if (feat_csdev) {
			/*
			 * At least one feature on this device matches the config
			 * add a config instance to the device and a reference to the feature.
			 */
			if (!config_csdev) {
				config_csdev = cscfg_alloc_csdev_cfg(csdev,
								     config_desc->nr_feat_refs);
				if (!config_csdev)
					return -ENOMEM;
				config_csdev->config_desc = config_desc;
			}
			config_csdev->feats_csdev[config_csdev->nr_feat++] = feat_csdev;
		}
	}
	/* if matched features, add config to device.*/
	if (config_csdev) {
		spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
		list_add(&config_csdev->node, &csdev->config_csdev_list);
		spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
	}

	return 0;
}

/*
 * Add the config to the set of registered devices - call with mutex locked.
 * Iterates through devices - any device that matches one or more of the
 * configuration features will load it, the others will ignore it.
 */
static int cscfg_add_cfg_to_csdevs(struct cscfg_config_desc *config_desc)
{
	struct cscfg_registered_csdev *csdev_item;
	int err;

	list_for_each_entry(