drivers/dca/dca-sysfs.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright(c) 2007 - 2009 Intel Corporation. All rights reserved.
 */

#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/idr.h>
#include <linux/kdev_t.h>
#include <linux/err.h>
#include <linux/dca.h>
#include <linux/gfp.h>
#include <linux/export.h>

static const struct class dca_class = {
	.name = "dca",
};
static struct idr dca_idr;
static spinlock_t dca_idr_lock;

int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot)
{
	struct device *cd;
	static int req_count;

	cd = device_create(&dca_class, dca->cd, MKDEV(0, slot + 1), NULL,
			   "requester%d", req_count++);
	return PTR_ERR_OR_ZERO(cd);
}

void dca_sysfs_remove_req(struct dca_provider *dca, int slot)
{
	device_destroy(&dca_class, MKDEV(0, slot + 1));
}

int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
{
	struct device *cd;
	int ret;

	idr_preload(GFP_KERNEL);
	spin_lock(&dca_idr_lock);

	ret = idr_alloc(&dca_idr, dca, 0, 0, GFP_NOWAIT);
	if (ret >= 0)
		dca->id = ret;

	spin_unlock(&dca_idr_lock);
	idr_preload_end();
	if (ret < 0)
		return ret;

	cd = device_create(&dca_class, dev, MKDEV(0, 0), NULL, "dca%d", dca->id);
	if (IS_ERR(cd)) {
		spin_lock(&dca_idr_lock);
		idr_remove(&dca_idr, dca->id);
		spin_unlock(&dca_idr_lock);
		return PTR_ERR(cd);
	}
	dca->cd = cd;
	return 0;
}

void dca_sysfs_remove_provider(struct dca_provider *dca)
{
	device_unregister(dca->cd);
	dca->cd = NULL;
	spin_lock(&dca_idr_lock);
	idr_remove(&dca_idr, dca->id);
	spin_unlock(&dca_idr_lock);
}

int __init dca_sysfs_init(void)
{
	int err;

	idr_init(&dca_idr);
	spin_lock_init(&dca_idr_lock);

	err = class_register(&dca_class);
	if (err) {
		idr_destroy(&dca_idr);
		return err;
	}
	return 0;
}

void __exit dca_sysfs_exit(void)
{
	class_unregister(&dca_class);
	idr_destroy(&dca_idr);
}