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7589670f SN |
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 | ||
7f1b358a | 31 | #define DCA_VERSION "1.4" |
7589670f | 32 | |
7f1b358a MS |
33 | MODULE_VERSION(DCA_VERSION); |
34 | MODULE_LICENSE("GPL"); | |
35 | MODULE_AUTHOR("Intel Corporation"); | |
7589670f SN |
36 | |
37 | static DEFINE_SPINLOCK(dca_lock); | |
38 | ||
7f1b358a MS |
39 | static LIST_HEAD(dca_providers); |
40 | ||
41 | static struct dca_provider *dca_find_provider_by_dev(struct device *dev) | |
42 | { | |
43 | struct dca_provider *dca, *ret = NULL; | |
44 | ||
45 | list_for_each_entry(dca, &dca_providers, node) { | |
46 | if ((!dev) || (dca->ops->dev_managed(dca, dev))) { | |
47 | ret = dca; | |
48 | break; | |
49 | } | |
50 | } | |
51 | ||
52 | return ret; | |
53 | } | |
7589670f SN |
54 | |
55 | /** | |
56 | * dca_add_requester - add a dca client to the list | |
57 | * @dev - the device that wants dca service | |
58 | */ | |
59 | int dca_add_requester(struct device *dev) | |
60 | { | |
7f1b358a MS |
61 | struct dca_provider *dca; |
62 | int err, slot = -ENODEV; | |
7589670f | 63 | |
7f1b358a MS |
64 | if (!dev) |
65 | return -EFAULT; | |
7589670f SN |
66 | |
67 | spin_lock(&dca_lock); | |
7f1b358a MS |
68 | |
69 | /* check if the requester has not been added already */ | |
70 | dca = dca_find_provider_by_dev(dev); | |
71 | if (dca) { | |
72 | spin_unlock(&dca_lock); | |
73 | return -EEXIST; | |
74 | } | |
75 | ||
76 | list_for_each_entry(dca, &dca_providers, node) { | |
77 | slot = dca->ops->add_requester(dca, dev); | |
78 | if (slot >= 0) | |
79 | break; | |
80 | } | |
81 | if (slot < 0) { | |
82 | spin_unlock(&dca_lock); | |
7589670f | 83 | return slot; |
7f1b358a | 84 | } |
7589670f | 85 | |
7f1b358a | 86 | err = dca_sysfs_add_req(dca, dev, slot); |
7589670f | 87 | if (err) { |
7f1b358a | 88 | dca->ops->remove_requester(dca, dev); |
7589670f SN |
89 | spin_unlock(&dca_lock); |
90 | return err; | |
91 | } | |
92 | ||
7f1b358a | 93 | spin_unlock(&dca_lock); |
7589670f SN |
94 | return 0; |
95 | } | |
96 | EXPORT_SYMBOL_GPL(dca_add_requester); | |
97 | ||
98 | /** | |
99 | * dca_remove_requester - remove a dca client from the list | |
100 | * @dev - the device that wants dca service | |
101 | */ | |
102 | int dca_remove_requester(struct device *dev) | |
103 | { | |
7f1b358a | 104 | struct dca_provider *dca; |
7589670f | 105 | int slot; |
7f1b358a MS |
106 | |
107 | if (!dev) | |
108 | return -EFAULT; | |
7589670f SN |
109 | |
110 | spin_lock(&dca_lock); | |
7f1b358a MS |
111 | dca = dca_find_provider_by_dev(dev); |
112 | if (!dca) { | |
113 | spin_unlock(&dca_lock); | |
114 | return -ENODEV; | |
115 | } | |
116 | slot = dca->ops->remove_requester(dca, dev); | |
117 | if (slot < 0) { | |
118 | spin_unlock(&dca_lock); | |
7589670f | 119 | return slot; |
7f1b358a | 120 | } |
7589670f | 121 | |
7f1b358a MS |
122 | dca_sysfs_remove_req(dca, slot); |
123 | ||
124 | spin_unlock(&dca_lock); | |
7589670f SN |
125 | return 0; |
126 | } | |
127 | EXPORT_SYMBOL_GPL(dca_remove_requester); | |
128 | ||
129 | /** | |
7f1b358a MS |
130 | * dca_common_get_tag - return the dca tag (serves both new and old api) |
131 | * @dev - the device that wants dca service | |
7589670f SN |
132 | * @cpu - the cpuid as returned by get_cpu() |
133 | */ | |
7f1b358a | 134 | u8 dca_common_get_tag(struct device *dev, int cpu) |
7589670f | 135 | { |
7f1b358a MS |
136 | struct dca_provider *dca; |
137 | u8 tag; | |
138 | ||
139 | spin_lock(&dca_lock); | |
140 | ||
141 | dca = dca_find_provider_by_dev(dev); | |
142 | if (!dca) { | |
143 | spin_unlock(&dca_lock); | |
7589670f | 144 | return -ENODEV; |
7f1b358a MS |
145 | } |
146 | tag = dca->ops->get_tag(dca, dev, cpu); | |
147 | ||
148 | spin_unlock(&dca_lock); | |
149 | return tag; | |
150 | } | |
151 | ||
152 | /** | |
153 | * dca3_get_tag - return the dca tag to the requester device | |
154 | * for the given cpu (new api) | |
155 | * @dev - the device that wants dca service | |
156 | * @cpu - the cpuid as returned by get_cpu() | |
157 | */ | |
158 | u8 dca3_get_tag(struct device *dev, int cpu) | |
159 | { | |
160 | if (!dev) | |
161 | return -EFAULT; | |
162 | ||
163 | return dca_common_get_tag(dev, cpu); | |
164 | } | |
165 | EXPORT_SYMBOL_GPL(dca3_get_tag); | |
166 | ||
167 | /** | |
168 | * dca_get_tag - return the dca tag for the given cpu (old api) | |
169 | * @cpu - the cpuid as returned by get_cpu() | |
170 | */ | |
171 | u8 dca_get_tag(int cpu) | |
172 | { | |
173 | struct device *dev = NULL; | |
174 | ||
175 | return dca_common_get_tag(dev, cpu); | |
7589670f SN |
176 | } |
177 | EXPORT_SYMBOL_GPL(dca_get_tag); | |
178 | ||
179 | /** | |
180 | * alloc_dca_provider - get data struct for describing a dca provider | |
181 | * @ops - pointer to struct of dca operation function pointers | |
182 | * @priv_size - size of extra mem to be added for provider's needs | |
183 | */ | |
184 | struct dca_provider *alloc_dca_provider(struct dca_ops *ops, int priv_size) | |
185 | { | |
186 | struct dca_provider *dca; | |
187 | int alloc_size; | |
188 | ||
189 | alloc_size = (sizeof(*dca) + priv_size); | |
190 | dca = kzalloc(alloc_size, GFP_KERNEL); | |
191 | if (!dca) | |
192 | return NULL; | |
193 | dca->ops = ops; | |
194 | ||
195 | return dca; | |
196 | } | |
197 | EXPORT_SYMBOL_GPL(alloc_dca_provider); | |
198 | ||
199 | /** | |
200 | * free_dca_provider - release the dca provider data struct | |
201 | * @ops - pointer to struct of dca operation function pointers | |
202 | * @priv_size - size of extra mem to be added for provider's needs | |
203 | */ | |
204 | void free_dca_provider(struct dca_provider *dca) | |
205 | { | |
206 | kfree(dca); | |
207 | } | |
208 | EXPORT_SYMBOL_GPL(free_dca_provider); | |
209 | ||
210 | static BLOCKING_NOTIFIER_HEAD(dca_provider_chain); | |
211 | ||
212 | /** | |
213 | * register_dca_provider - register a dca provider | |
214 | * @dca - struct created by alloc_dca_provider() | |
215 | * @dev - device providing dca services | |
216 | */ | |
217 | int register_dca_provider(struct dca_provider *dca, struct device *dev) | |
218 | { | |
219 | int err; | |
220 | ||
7589670f SN |
221 | err = dca_sysfs_add_provider(dca, dev); |
222 | if (err) | |
223 | return err; | |
7f1b358a | 224 | list_add(&dca->node, &dca_providers); |
7589670f SN |
225 | blocking_notifier_call_chain(&dca_provider_chain, |
226 | DCA_PROVIDER_ADD, NULL); | |
227 | return 0; | |
228 | } | |
229 | EXPORT_SYMBOL_GPL(register_dca_provider); | |
230 | ||
231 | /** | |
232 | * unregister_dca_provider - remove a dca provider | |
233 | * @dca - struct created by alloc_dca_provider() | |
234 | */ | |
235 | void unregister_dca_provider(struct dca_provider *dca) | |
236 | { | |
7589670f SN |
237 | blocking_notifier_call_chain(&dca_provider_chain, |
238 | DCA_PROVIDER_REMOVE, NULL); | |
7f1b358a | 239 | list_del(&dca->node); |
7589670f SN |
240 | dca_sysfs_remove_provider(dca); |
241 | } | |
242 | EXPORT_SYMBOL_GPL(unregister_dca_provider); | |
243 | ||
244 | /** | |
245 | * dca_register_notify - register a client's notifier callback | |
246 | */ | |
247 | void dca_register_notify(struct notifier_block *nb) | |
248 | { | |
249 | blocking_notifier_chain_register(&dca_provider_chain, nb); | |
250 | } | |
251 | EXPORT_SYMBOL_GPL(dca_register_notify); | |
252 | ||
253 | /** | |
254 | * dca_unregister_notify - remove a client's notifier callback | |
255 | */ | |
256 | void dca_unregister_notify(struct notifier_block *nb) | |
257 | { | |
258 | blocking_notifier_chain_unregister(&dca_provider_chain, nb); | |
259 | } | |
260 | EXPORT_SYMBOL_GPL(dca_unregister_notify); | |
261 | ||
262 | static int __init dca_init(void) | |
263 | { | |
7f1b358a | 264 | printk(KERN_ERR "dca service started, version %s\n", DCA_VERSION); |
7589670f SN |
265 | return dca_sysfs_init(); |
266 | } | |
267 | ||
268 | static void __exit dca_exit(void) | |
269 | { | |
270 | dca_sysfs_exit(); | |
271 | } | |
272 | ||
273 | module_init(dca_init); | |
274 | module_exit(dca_exit); | |
275 |