dca-sysfs.c

 1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 * Copyright(c) 2007 - 2009 Intel Corporation. All rights reserved.
 4 */
 5
 6#include <linux/kernel.h>
 7#include <linux/spinlock.h>
 8#include <linux/device.h>
 9#include <linux/idr.h>
10#include <linux/kdev_t.h>
11#include <linux/err.h>
12#include <linux/dca.h>
13#include <linux/gfp.h>
14#include <linux/export.h>
15
16static const struct class dca_class = {
17	.name = "dca",
18};
19static struct idr dca_idr;
20static spinlock_t dca_idr_lock;
21
22int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot)
23{
24	struct device *cd;
25	static int req_count;
26
27	cd = device_create(&dca_class, dca->cd, MKDEV(0, slot + 1), NULL,
28			   "requester%d", req_count++);
29	return PTR_ERR_OR_ZERO(cd);
30}
31
32void dca_sysfs_remove_req(struct dca_provider *dca, int slot)
33{
34	device_destroy(&dca_class, MKDEV(0, slot + 1));
35}
36
37int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
38{
39	struct device *cd;
40	int ret;
41
42	idr_preload(GFP_KERNEL);
43	spin_lock(&dca_idr_lock);
44
45	ret = idr_alloc(&dca_idr, dca, 0, 0, GFP_NOWAIT);
46	if (ret >= 0)
47		dca->id = ret;
48
49	spin_unlock(&dca_idr_lock);
50	idr_preload_end();
51	if (ret < 0)
52		return ret;
53
54	cd = device_create(&dca_class, dev, MKDEV(0, 0), NULL, "dca%d", dca->id);
55	if (IS_ERR(cd)) {
56		spin_lock(&dca_idr_lock);
57		idr_remove(&dca_idr, dca->id);
58		spin_unlock(&dca_idr_lock);
59		return PTR_ERR(cd);
60	}
61	dca->cd = cd;
62	return 0;
63}
64
65void dca_sysfs_remove_provider(struct dca_provider *dca)
66{
67	device_unregister(dca->cd);
68	dca->cd = NULL;
69	spin_lock(&dca_idr_lock);
70	idr_remove(&dca_idr, dca->id);
71	spin_unlock(&dca_idr_lock);
72}
73
74int __init dca_sysfs_init(void)
75{
76	int err;
77
78	idr_init(&dca_idr);
79	spin_lock_init(&dca_idr_lock);
80
81	err = class_register(&dca_class);
82	if (err) {
83		idr_destroy(&dca_idr);
84		return err;
85	}
86	return 0;
87}
88
89void __exit dca_sysfs_exit(void)
90{
91	class_unregister(&dca_class);
92	idr_destroy(&dca_idr);
93}
94