Root/drivers/dca/dca-sysfs.c

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
31static struct class *dca_class;
32static struct idr dca_idr;
33static spinlock_t dca_idr_lock;
34
35int dca_sysfs_add_req(struct dca_provider *dca, struct device *dev, int slot)
36{
37    struct device *cd;
38    static int req_count;
39
40    cd = device_create(dca_class, dca->cd, MKDEV(0, slot + 1), NULL,
41               "requester%d", req_count++);
42    if (IS_ERR(cd))
43        return PTR_ERR(cd);
44    return 0;
45}
46
47void dca_sysfs_remove_req(struct dca_provider *dca, int slot)
48{
49    device_destroy(dca_class, MKDEV(0, slot + 1));
50}
51
52int dca_sysfs_add_provider(struct dca_provider *dca, struct device *dev)
53{
54    struct device *cd;
55    int err = 0;
56
57idr_try_again:
58    if (!idr_pre_get(&dca_idr, GFP_KERNEL))
59        return -ENOMEM;
60    spin_lock(&dca_idr_lock);
61    err = idr_get_new(&dca_idr, dca, &dca->id);
62    spin_unlock(&dca_idr_lock);
63    switch (err) {
64    case 0:
65        break;
66    case -EAGAIN:
67        goto idr_try_again;
68    default:
69        return err;
70    }
71
72    cd = device_create(dca_class, dev, MKDEV(0, 0), NULL, "dca%d", dca->id);
73    if (IS_ERR(cd)) {
74        spin_lock(&dca_idr_lock);
75        idr_remove(&dca_idr, dca->id);
76        spin_unlock(&dca_idr_lock);
77        return PTR_ERR(cd);
78    }
79    dca->cd = cd;
80    return 0;
81}
82
83void dca_sysfs_remove_provider(struct dca_provider *dca)
84{
85    device_unregister(dca->cd);
86    dca->cd = NULL;
87    spin_lock(&dca_idr_lock);
88    idr_remove(&dca_idr, dca->id);
89    spin_unlock(&dca_idr_lock);
90}
91
92int __init dca_sysfs_init(void)
93{
94    idr_init(&dca_idr);
95    spin_lock_init(&dca_idr_lock);
96
97    dca_class = class_create(THIS_MODULE, "dca");
98    if (IS_ERR(dca_class)) {
99        idr_destroy(&dca_idr);
100        return PTR_ERR(dca_class);
101    }
102    return 0;
103}
104
105void __exit dca_sysfs_exit(void)
106{
107    class_destroy(dca_class);
108    idr_destroy(&dca_idr);
109}
110
111

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