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1 | /* |
2 | * Copyright(c) 2007 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 | /* | |
23 | * This driver supports an interface for DCA clients and providers to meet. | |
24 | */ | |
25 | ||
26 | #include <linux/kernel.h> | |
27 | #include <linux/notifier.h> | |
28 | #include <linux/device.h> | |
29 | #include <linux/dca.h> | |
30 | ||
31 | MODULE_LICENSE("GPL"); | |
32 | ||
33 | /* For now we're assuming a single, global, DCA provider for the system. */ | |
34 | ||
35 | static DEFINE_SPINLOCK(dca_lock); | |
36 | ||
37 | static struct dca_provider *global_dca = NULL; | |
38 | ||
39 | /** | |
40 | * dca_add_requester - add a dca client to the list | |
41 | * @dev - the device that wants dca service | |
42 | */ | |
43 | int dca_add_requester(struct device *dev) | |
44 | { | |
45 | int err, slot; | |
46 | ||
47 | if (!global_dca) | |
48 | return -ENODEV; | |
49 | ||
50 | spin_lock(&dca_lock); | |
51 | slot = global_dca->ops->add_requester(global_dca, dev); | |
52 | spin_unlock(&dca_lock); | |
53 | if (slot < 0) | |
54 | return slot; | |
55 | ||
56 | err = dca_sysfs_add_req(global_dca, dev, slot); | |
57 | if (err) { | |
58 | spin_lock(&dca_lock); | |
59 | global_dca->ops->remove_requester(global_dca, dev); | |
60 | spin_unlock(&dca_lock); | |
61 | return err; | |
62 | } | |
63 | ||
64 | return 0; | |
65 | } | |
66 | EXPORT_SYMBOL_GPL(dca_add_requester); | |
67 | ||
68 | /** | |
69 | * dca_remove_requester - remove a dca client from the list | |
70 | * @dev - the device that wants dca service | |
71 | */ | |
72 | int dca_remove_requester(struct device *dev) | |
73 | { | |
74 | int slot; | |
75 | if (!global_dca) | |
76 | return -ENODEV; | |
77 | ||
78 | spin_lock(&dca_lock); | |
79 | slot = global_dca->ops->remove_requester(global_dca, dev); | |
80 | spin_unlock(&dca_lock); | |
81 | if (slot < 0) | |
82 | return slot; | |
83 | ||
84 | dca_sysfs_remove_req(global_dca, slot); | |
85 | return 0; | |
86 | } | |
87 | EXPORT_SYMBOL_GPL(dca_remove_requester); | |
88 | ||
89 | /** | |
90 | * dca_get_tag - return the dca tag for the given cpu | |
91 | * @cpu - the cpuid as returned by get_cpu() | |
92 | */ | |
93 | u8 dca_get_tag(int cpu) | |
94 | { | |
95 | if (!global_dca) | |
96 | return -ENODEV; | |
97 | return global_dca->ops->get_tag(global_dca, cpu); | |
98 | } | |
99 | EXPORT_SYMBOL_GPL(dca_get_tag); | |
100 | ||
101 | /** | |
102 | * alloc_dca_provider - get data struct for describing a dca provider | |
103 | * @ops - pointer to struct of dca operation function pointers | |
104 | * @priv_size - size of extra mem to be added for provider's needs | |
105 | */ | |
106 | struct dca_provider *alloc_dca_provider(struct dca_ops *ops, int priv_size) | |
107 | { | |
108 | struct dca_provider *dca; | |
109 | int alloc_size; | |
110 | ||
111 | alloc_size = (sizeof(*dca) + priv_size); | |
112 | dca = kzalloc(alloc_size, GFP_KERNEL); | |
113 | if (!dca) | |
114 | return NULL; | |
115 | dca->ops = ops; | |
116 | ||
117 | return dca; | |
118 | } | |
119 | EXPORT_SYMBOL_GPL(alloc_dca_provider); | |
120 | ||
121 | /** | |
122 | * free_dca_provider - release the dca provider data struct | |
123 | * @ops - pointer to struct of dca operation function pointers | |
124 | * @priv_size - size of extra mem to be added for provider's needs | |
125 | */ | |
126 | void free_dca_provider(struct dca_provider *dca) | |
127 | { | |
128 | kfree(dca); | |
129 | } | |
130 | EXPORT_SYMBOL_GPL(free_dca_provider); | |
131 | ||
132 | static BLOCKING_NOTIFIER_HEAD(dca_provider_chain); | |
133 | ||
134 | /** | |
135 | * register_dca_provider - register a dca provider | |
136 | * @dca - struct created by alloc_dca_provider() | |
137 | * @dev - device providing dca services | |
138 | */ | |
139 | int register_dca_provider(struct dca_provider *dca, struct device *dev) | |
140 | { | |
141 | int err; | |
142 | ||
143 | if (global_dca) | |
144 | return -EEXIST; | |
145 | err = dca_sysfs_add_provider(dca, dev); | |
146 | if (err) | |
147 | return err; | |
148 | global_dca = dca; | |
149 | blocking_notifier_call_chain(&dca_provider_chain, | |
150 | DCA_PROVIDER_ADD, NULL); | |
151 | return 0; | |
152 | } | |
153 | EXPORT_SYMBOL_GPL(register_dca_provider); | |
154 | ||
155 | /** | |
156 | * unregister_dca_provider - remove a dca provider | |
157 | * @dca - struct created by alloc_dca_provider() | |
158 | */ | |
159 | void unregister_dca_provider(struct dca_provider *dca) | |
160 | { | |
161 | if (!global_dca) | |
162 | return; | |
163 | blocking_notifier_call_chain(&dca_provider_chain, | |
164 | DCA_PROVIDER_REMOVE, NULL); | |
165 | global_dca = NULL; | |
166 | dca_sysfs_remove_provider(dca); | |
167 | } | |
168 | EXPORT_SYMBOL_GPL(unregister_dca_provider); | |
169 | ||
170 | /** | |
171 | * dca_register_notify - register a client's notifier callback | |
172 | */ | |
173 | void dca_register_notify(struct notifier_block *nb) | |
174 | { | |
175 | blocking_notifier_chain_register(&dca_provider_chain, nb); | |
176 | } | |
177 | EXPORT_SYMBOL_GPL(dca_register_notify); | |
178 | ||
179 | /** | |
180 | * dca_unregister_notify - remove a client's notifier callback | |
181 | */ | |
182 | void dca_unregister_notify(struct notifier_block *nb) | |
183 | { | |
184 | blocking_notifier_chain_unregister(&dca_provider_chain, nb); | |
185 | } | |
186 | EXPORT_SYMBOL_GPL(dca_unregister_notify); | |
187 | ||
188 | static int __init dca_init(void) | |
189 | { | |
190 | return dca_sysfs_init(); | |
191 | } | |
192 | ||
193 | static void __exit dca_exit(void) | |
194 | { | |
195 | dca_sysfs_exit(); | |
196 | } | |
197 | ||
198 | module_init(dca_init); | |
199 | module_exit(dca_exit); | |
200 |