Root/drivers/dca/dca-core.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/*
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
388

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