Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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/*
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#include <linux/slab.h>
31
32#define DCA_VERSION "1.12.1"
33
34MODULE_VERSION(DCA_VERSION);
35MODULE_LICENSE("GPL");
36MODULE_AUTHOR("Intel Corporation");
37
38static DEFINE_SPINLOCK(dca_lock);
39
40static LIST_HEAD(dca_domains);
41
42static struct pci_bus *dca_pci_rc_from_dev(struct device *dev)
43{
44 struct pci_dev *pdev = to_pci_dev(dev);
45 struct pci_bus *bus = pdev->bus;
46
47 while (bus->parent)
48 bus = bus->parent;
49
50 return bus;
51}
52
53static struct dca_domain *dca_allocate_domain(struct pci_bus *rc)
54{
55 struct dca_domain *domain;
56
57 domain = kzalloc(sizeof(*domain), GFP_NOWAIT);
58 if (!domain)
59 return NULL;
60
61 INIT_LIST_HEAD(&domain->dca_providers);
62 domain->pci_rc = rc;
63
64 return domain;
65}
66
67static void dca_free_domain(struct dca_domain *domain)
68{
69 list_del(&domain->node);
70 kfree(domain);
71}
72
73static struct dca_domain *dca_find_domain(struct pci_bus *rc)
74{
75 struct dca_domain *domain;
76
77 list_for_each_entry(domain, &dca_domains, node)
78 if (domain->pci_rc == rc)
79 return domain;
80
81 return NULL;
82}
83
84static struct dca_domain *dca_get_domain(struct device *dev)
85{
86 struct pci_bus *rc;
87 struct dca_domain *domain;
88
89 rc = dca_pci_rc_from_dev(dev);
90 domain = dca_find_domain(rc);
91
92 if (!domain) {
93 domain = dca_allocate_domain(rc);
94 if (domain)
95 list_add(&domain->node, &dca_domains);
96 }
97
98 return domain;
99}
100
101static struct dca_provider *dca_find_provider_by_dev(struct device *dev)
102{
103 struct dca_provider *dca;
104 struct pci_bus *rc;
105 struct dca_domain *domain;
106
107 if (dev) {
108 rc = dca_pci_rc_from_dev(dev);
109 domain = dca_find_domain(rc);
110 if (!domain)
111 return NULL;
112 } else {
113 if (!list_empty(&dca_domains))
114 domain = list_first_entry(&dca_domains,
115 struct dca_domain,
116 node);
117 else
118 return NULL;
119 }
120
121 list_for_each_entry(dca, &domain->dca_providers, node)
122 if ((!dev) || (dca->ops->dev_managed(dca, dev)))
123 return dca;
124
125 return NULL;
126}
127
128/**
129 * dca_add_requester - add a dca client to the list
130 * @dev - the device that wants dca service
131 */
132int dca_add_requester(struct device *dev)
133{
134 struct dca_provider *dca;
135 int err, slot = -ENODEV;
136 unsigned long flags;
137 struct pci_bus *pci_rc;
138 struct dca_domain *domain;
139
140 if (!dev)
141 return -EFAULT;
142
143 spin_lock_irqsave(&dca_lock, flags);
144
145 /* check if the requester has not been added already */
146 dca = dca_find_provider_by_dev(dev);
147 if (dca) {
148 spin_unlock_irqrestore(&dca_lock, flags);
149 return -EEXIST;
150 }
151
152 pci_rc = dca_pci_rc_from_dev(dev);
153 domain = dca_find_domain(pci_rc);
154 if (!domain) {
155 spin_unlock_irqrestore(&dca_lock, flags);
156 return -ENODEV;
157 }
158
159 list_for_each_entry(dca, &domain->dca_providers, node) {
160 slot = dca->ops->add_requester(dca, dev);
161 if (slot >= 0)
162 break;
163 }
164
165 spin_unlock_irqrestore(&dca_lock, flags);
166
167 if (slot < 0)
168 return slot;
169
170 err = dca_sysfs_add_req(dca, dev, slot);
171 if (err) {
172 spin_lock_irqsave(&dca_lock, flags);
173 if (dca == dca_find_provider_by_dev(dev))
174 dca->ops->remove_requester(dca, dev);
175 spin_unlock_irqrestore(&dca_lock, flags);
176 return err;
177 }
178
179 return 0;
180}
181EXPORT_SYMBOL_GPL(dca_add_requester);
182
183/**
184 * dca_remove_requester - remove a dca client from the list
185 * @dev - the device that wants dca service
186 */
187int dca_remove_requester(struct device *dev)
188{
189 struct dca_provider *dca;
190 int slot;
191 unsigned long flags;
192
193 if (!dev)
194 return -EFAULT;
195
196 spin_lock_irqsave(&dca_lock, flags);
197 dca = dca_find_provider_by_dev(dev);
198 if (!dca) {
199 spin_unlock_irqrestore(&dca_lock, flags);
200 return -ENODEV;
201 }
202 slot = dca->ops->remove_requester(dca, dev);
203 spin_unlock_irqrestore(&dca_lock, flags);
204
205 if (slot < 0)
206 return slot;
207
208 dca_sysfs_remove_req(dca, slot);
209
210 return 0;
211}
212EXPORT_SYMBOL_GPL(dca_remove_requester);
213
214/**
215 * dca_common_get_tag - return the dca tag (serves both new and old api)
216 * @dev - the device that wants dca service
217 * @cpu - the cpuid as returned by get_cpu()
218 */
219u8 dca_common_get_tag(struct device *dev, int cpu)
220{
221 struct dca_provider *dca;
222 u8 tag;
223 unsigned long flags;
224
225 spin_lock_irqsave(&dca_lock, flags);
226
227 dca = dca_find_provider_by_dev(dev);
228 if (!dca) {
229 spin_unlock_irqrestore(&dca_lock, flags);
230 return -ENODEV;
231 }
232 tag = dca->ops->get_tag(dca, dev, cpu);
233
234 spin_unlock_irqrestore(&dca_lock, flags);
235 return tag;
236}
237
238/**
239 * dca3_get_tag - return the dca tag to the requester device
240 * for the given cpu (new api)
241 * @dev - the device that wants dca service
242 * @cpu - the cpuid as returned by get_cpu()
243 */
244u8 dca3_get_tag(struct device *dev, int cpu)
245{
246 if (!dev)
247 return -EFAULT;
248
249 return dca_common_get_tag(dev, cpu);
250}
251EXPORT_SYMBOL_GPL(dca3_get_tag);
252
253/**
254 * dca_get_tag - return the dca tag for the given cpu (old api)
255 * @cpu - the cpuid as returned by get_cpu()
256 */
257u8 dca_get_tag(int cpu)
258{
259 struct device *dev = NULL;
260
261 return dca_common_get_tag(dev, cpu);
262}
263EXPORT_SYMBOL_GPL(dca_get_tag);
264
265/**
266 * alloc_dca_provider - get data struct for describing a dca provider
267 * @ops - pointer to struct of dca operation function pointers
268 * @priv_size - size of extra mem to be added for provider's needs
269 */
270struct dca_provider *alloc_dca_provider(struct dca_ops *ops, int priv_size)
271{
272 struct dca_provider *dca;
273 int alloc_size;
274
275 alloc_size = (sizeof(*dca) + priv_size);
276 dca = kzalloc(alloc_size, GFP_KERNEL);
277 if (!dca)
278 return NULL;
279 dca->ops = ops;
280
281 return dca;
282}
283EXPORT_SYMBOL_GPL(alloc_dca_provider);
284
285/**
286 * free_dca_provider - release the dca provider data struct
287 * @ops - pointer to struct of dca operation function pointers
288 * @priv_size - size of extra mem to be added for provider's needs
289 */
290void free_dca_provider(struct dca_provider *dca)
291{
292 kfree(dca);
293}
294EXPORT_SYMBOL_GPL(free_dca_provider);
295
296static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);
297
298/**
299 * register_dca_provider - register a dca provider
300 * @dca - struct created by alloc_dca_provider()
301 * @dev - device providing dca services
302 */
303int register_dca_provider(struct dca_provider *dca, struct device *dev)
304{
305 int err;
306 unsigned long flags;
307 struct dca_domain *domain;
308
309 err = dca_sysfs_add_provider(dca, dev);
310 if (err)
311 return err;
312
313 spin_lock_irqsave(&dca_lock, flags);
314 domain = dca_get_domain(dev);
315 if (!domain) {
316 spin_unlock_irqrestore(&dca_lock, flags);
317 return -ENODEV;
318 }
319 list_add(&dca->node, &domain->dca_providers);
320 spin_unlock_irqrestore(&dca_lock, flags);
321
322 blocking_notifier_call_chain(&dca_provider_chain,
323 DCA_PROVIDER_ADD, NULL);
324 return 0;
325}
326EXPORT_SYMBOL_GPL(register_dca_provider);
327
328/**
329 * unregister_dca_provider - remove a dca provider
330 * @dca - struct created by alloc_dca_provider()
331 */
332void unregister_dca_provider(struct dca_provider *dca, struct device *dev)
333{
334 unsigned long flags;
335 struct pci_bus *pci_rc;
336 struct dca_domain *domain;
337
338 blocking_notifier_call_chain(&dca_provider_chain,
339 DCA_PROVIDER_REMOVE, NULL);
340
341 spin_lock_irqsave(&dca_lock, flags);
342
343 list_del(&dca->node);
344
345 pci_rc = dca_pci_rc_from_dev(dev);
346 domain = dca_find_domain(pci_rc);
347 if (list_empty(&domain->dca_providers))
348 dca_free_domain(domain);
349
350 spin_unlock_irqrestore(&dca_lock, flags);
351
352 dca_sysfs_remove_provider(dca);
353}
354EXPORT_SYMBOL_GPL(unregister_dca_provider);
355
356/**
357 * dca_register_notify - register a client's notifier callback
358 */
359void dca_register_notify(struct notifier_block *nb)
360{
361 blocking_notifier_chain_register(&dca_provider_chain, nb);
362}
363EXPORT_SYMBOL_GPL(dca_register_notify);
364
365/**
366 * dca_unregister_notify - remove a client's notifier callback
367 */
368void dca_unregister_notify(struct notifier_block *nb)
369{
370 blocking_notifier_chain_unregister(&dca_provider_chain, nb);
371}
372EXPORT_SYMBOL_GPL(dca_unregister_notify);
373
374static int __init dca_init(void)
375{
376 pr_info("dca service started, version %s\n", DCA_VERSION);
377 return dca_sysfs_init();
378}
379
380static void __exit dca_exit(void)
381{
382 dca_sysfs_exit();
383}
384
385arch_initcall(dca_init);
386module_exit(dca_exit);
387