1 /*
2  * Copyright(c) 2007 - 2009 Intel Corporation. All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or modify it
5  * under the terms of the GNU General Public License as published by the Free
6  * Software Foundation; either version 2 of the License, or (at your option)
7  * any later version.
8  *
9  * This program is distributed in the hope that it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12  * more details.
13  *
14  * You should have received a copy of the GNU General Public License along with
15  * this program; if not, write to the Free Software Foundation, Inc., 59
16  * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
17  *
18  * The full GNU General Public License is included in this distribution in the
19  * file called COPYING.
20  */
21 
22 #include <linux/kernel.h>
23 #include <linux/spinlock.h>
24 #include <linux/device.h>
25 #include <linux/idr.h>
26 #include <linux/kdev_t.h>
27 #include <linux/err.h>
28 #include <linux/dca.h>
29 #include <linux/gfp.h>
30 #include <linux/export.h>
31 
32 static struct class *dca_class;
33 static struct idr dca_idr;
34 static spinlock_t dca_idr_lock;
35 
dca_sysfs_add_req(struct dca_provider * dca,struct device * dev,int slot)36 int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot)
37 {
38 	struct device *cd;
39 	static int req_count;
40 
41 	cd = device_create(dca_class, dca->cd, MKDEV(0, slot + 1), NULL,
42 			   "requester%d", req_count++);
43 	if (IS_ERR(cd))
44 		return PTR_ERR(cd);
45 	return 0;
46 }
47 
dca_sysfs_remove_req(struct dca_provider * dca,int slot)48 void dca_sysfs_remove_req(struct dca_provider *dca, int slot)
49 {
50 	device_destroy(dca_class, MKDEV(0, slot + 1));
51 }
52 
dca_sysfs_add_provider(struct dca_provider * dca,struct device * dev)53 int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
54 {
55 	struct device *cd;
56 	int err = 0;
57 
58 idr_try_again:
59 	if (!idr_pre_get(&dca_idr, GFP_KERNEL))
60 		return -ENOMEM;
61 	spin_lock(&dca_idr_lock);
62 	err = idr_get_new(&dca_idr, dca, &dca->id);
63 	spin_unlock(&dca_idr_lock);
64 	switch (err) {
65 	case 0:
66 		break;
67 	case -EAGAIN:
68 		goto idr_try_again;
69 	default:
70 		return err;
71 	}
72 
73 	cd = device_create(dca_class, dev, MKDEV(0, 0), NULL, "dca%d", dca->id);
74 	if (IS_ERR(cd)) {
75 		spin_lock(&dca_idr_lock);
76 		idr_remove(&dca_idr, dca->id);
77 		spin_unlock(&dca_idr_lock);
78 		return PTR_ERR(cd);
79 	}
80 	dca->cd = cd;
81 	return 0;
82 }
83 
dca_sysfs_remove_provider(struct dca_provider * dca)84 void dca_sysfs_remove_provider(struct dca_provider *dca)
85 {
86 	device_unregister(dca->cd);
87 	dca->cd = NULL;
88 	spin_lock(&dca_idr_lock);
89 	idr_remove(&dca_idr, dca->id);
90 	spin_unlock(&dca_idr_lock);
91 }
92 
dca_sysfs_init(void)93 int __init dca_sysfs_init(void)
94 {
95 	idr_init(&dca_idr);
96 	spin_lock_init(&dca_idr_lock);
97 
98 	dca_class = class_create(THIS_MODULE, "dca");
99 	if (IS_ERR(dca_class)) {
100 		idr_destroy(&dca_idr);
101 		return PTR_ERR(dca_class);
102 	}
103 	return 0;
104 }
105 
dca_sysfs_exit(void)106 void __exit dca_sysfs_exit(void)
107 {
108 	class_destroy(dca_class);
109 	idr_destroy(&dca_idr);
110 }
111 
112