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#include <linux/module.h>
32
33#define DCA_VERSION "1.12.1"
34
35MODULE_VERSION(DCA_VERSION);
36MODULE_LICENSE("GPL");
37MODULE_AUTHOR("Intel Corporation");
38
39static DEFINE_RAW_SPINLOCK(dca_lock);
40
41static LIST_HEAD(dca_domains);
42
43static BLOCKING_NOTIFIER_HEAD(dca_provider_chain);
44
45static int dca_providers_blocked;
46
47static struct pci_bus *dca_pci_rc_from_dev(struct device *dev)
48{
49 struct pci_dev *pdev = to_pci_dev(dev);
50 struct pci_bus *bus = pdev->bus;
51
52 while (bus->parent)
53 bus = bus->parent;
54
55 return bus;
56}
57
58static struct dca_domain *dca_allocate_domain(struct pci_bus *rc)
59{
60 struct dca_domain *domain;
61
62 domain = kzalloc(sizeof(*domain), GFP_NOWAIT);
63 if (!domain)
64 return NULL;
65
66 INIT_LIST_HEAD(&domain->dca_providers);
67 domain->pci_rc = rc;
68
69 return domain;
70}
71
72static void dca_free_domain(struct dca_domain *domain)
73{
74 list_del(&domain->node);
75 kfree(domain);
76}
77
78static int dca_provider_ioat_ver_3_0(struct device *dev)
79{
80 struct pci_dev *pdev = to_pci_dev(dev);
81
82 return ((pdev->vendor == PCI_VENDOR_ID_INTEL) &&
83 ((pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG0) ||
84 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG1) ||
85 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG2) ||
86 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG3) ||
87 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG4) ||
88 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG5) ||
89 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG6) ||
90 (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG7)));
91}
92
93static void unregister_dca_providers(void)
94{
95 struct dca_provider *dca, *_dca;
96 struct list_head unregistered_providers;
97 struct dca_domain *domain;
98 unsigned long flags;
99
100 blocking_notifier_call_chain(&dca_provider_chain,
101 DCA_PROVIDER_REMOVE, NULL);
102
103 INIT_LIST_HEAD(&unregistered_providers);
104
105 raw_spin_lock_irqsave(&dca_lock, flags);
106
107 if (list_empty(&dca_domains)) {
108 raw_spin_unlock_irqrestore(&dca_lock, flags);
109 return;
110 }
111
112 /* at this point only one domain in the list is expected */
113 domain = list_first_entry(&dca_domains, struct dca_domain, node);
114
115 list_for_each_entry_safe(dca, _dca, &domain->dca_providers, node)
116 list_move(&dca->node, &unregistered_providers);
117
118 dca_free_domain(domain);
119
120 raw_spin_unlock_irqrestore(&dca_lock, flags);
121
122 list_for_each_entry_safe(dca, _dca, &unregistered_providers, node) {
123 dca_sysfs_remove_provider(dca);
124 list_del(&dca->node);
125 }
126}
127
128static struct dca_domain *dca_find_domain(struct pci_bus *rc)
129{
130 struct dca_domain *domain;
131
132 list_for_each_entry(domain, &dca_domains, node)
133 if (domain->pci_rc == rc)
134 return domain;
135
136 return NULL;
137}
138
139static struct dca_domain *dca_get_domain(struct device *dev)
140{
141 struct pci_bus *rc;
142 struct dca_domain *domain;
143
144 rc = dca_pci_rc_from_dev(dev);
145 domain = dca_find_domain(rc);
146
147 if (!domain) {
148 if (dca_provider_ioat_ver_3_0(dev) && !list_empty(&dca_domains))
149 dca_providers_blocked = 1;
150 }
151
152 return domain;
153}
154
155static struct dca_provider *dca_find_provider_by_dev(struct device *dev)
156{
157 struct dca_provider *dca;
158 struct pci_bus *rc;
159 struct dca_domain *domain;
160
161 if (dev) {
162 rc = dca_pci_rc_from_dev(dev);
163 domain = dca_find_domain(rc);
164 if (!domain)
165 return NULL;
166 } else {
167 if (!list_empty(&dca_domains))
168 domain = list_first_entry(&dca_domains,
169 struct dca_domain,
170 node);
171 else
172 return NULL;
173 }
174
175 list_for_each_entry(dca, &domain->dca_providers, node)
176 if ((!dev) || (dca->ops->dev_managed(dca, dev)))
177 return dca;
178
179 return NULL;
180}
181
182/**
183 * dca_add_requester - add a dca client to the list
184 * @dev - the device that wants dca service
185 */
186int dca_add_requester(struct device *dev)
187{
188 struct dca_provider *dca;
189 int err, slot = -ENODEV;
190 unsigned long flags;
191 struct pci_bus *pci_rc;
192 struct dca_domain *domain;
193
194 if (!dev)
195 return -EFAULT;
196
197 raw_spin_lock_irqsave(&dca_lock, flags);
198
199 /* check if the requester has not been added already */
200 dca = dca_find_provider_by_dev(dev);
201 if (dca) {
202 raw_spin_unlock_irqrestore(&dca_lock, flags);
203 return -EEXIST;
204 }
205
206 pci_rc = dca_pci_rc_from_dev(dev);
207 domain = dca_find_domain(pci_rc);
208 if (!domain) {
209 raw_spin_unlock_irqrestore(&dca_lock, flags);
210 return -ENODEV;
211 }
212
213 list_for_each_entry(dca, &domain->dca_providers, node) {
214 slot = dca->ops->add_requester(dca, dev);
215 if (slot >= 0)
216 break;
217 }
218
219 raw_spin_unlock_irqrestore(&dca_lock, flags);
220
221 if (slot < 0)
222 return slot;
223
224 err = dca_sysfs_add_req(dca, dev, slot);
225 if (err) {
226 raw_spin_lock_irqsave(&dca_lock, flags);
227 if (dca == dca_find_provider_by_dev(dev))
228 dca->ops->remove_requester(dca, dev);
229 raw_spin_unlock_irqrestore(&dca_lock, flags);
230 return err;
231 }
232
233 return 0;
234}
235EXPORT_SYMBOL_GPL(dca_add_requester);
236
237/**
238 * dca_remove_requester - remove a dca client from the list
239 * @dev - the device that wants dca service
240 */
241int dca_remove_requester(struct device *dev)
242{
243 struct dca_provider *dca;
244 int slot;
245 unsigned long flags;
246
247 if (!dev)
248 return -EFAULT;
249
250 raw_spin_lock_irqsave(&dca_lock, flags);
251 dca = dca_find_provider_by_dev(dev);
252 if (!dca) {
253 raw_spin_unlock_irqrestore(&dca_lock, flags);
254 return -ENODEV;
255 }
256 slot = dca->ops->remove_requester(dca, dev);
257 raw_spin_unlock_irqrestore(&dca_lock, flags);
258
259 if (slot < 0)
260 return slot;
261
262 dca_sysfs_remove_req(dca, slot);
263
264 return 0;
265}
266EXPORT_SYMBOL_GPL(dca_remove_requester);
267
268/**
269 * dca_common_get_tag - return the dca tag (serves both new and old api)
270 * @dev - the device that wants dca service
271 * @cpu - the cpuid as returned by get_cpu()
272 */
273static u8 dca_common_get_tag(struct device *dev, int cpu)
274{
275 struct dca_provider *dca;
276 u8 tag;
277 unsigned long flags;
278
279 raw_spin_lock_irqsave(&dca_lock, flags);
280
281 dca = dca_find_provider_by_dev(dev);
282 if (!dca) {
283 raw_spin_unlock_irqrestore(&dca_lock, flags);
284 return -ENODEV;
285 }
286 tag = dca->ops->get_tag(dca, dev, cpu);
287
288 raw_spin_unlock_irqrestore(&dca_lock, flags);
289 return tag;
290}
291
292/**
293 * dca3_get_tag - return the dca tag to the requester device
294 * for the given cpu (new api)
295 * @dev - the device that wants dca service
296 * @cpu - the cpuid as returned by get_cpu()
297 */
298u8 dca3_get_tag(struct device *dev, int cpu)
299{
300 if (!dev)
301 return -EFAULT;
302
303 return dca_common_get_tag(dev, cpu);
304}
305EXPORT_SYMBOL_GPL(dca3_get_tag);
306
307/**
308 * dca_get_tag - return the dca tag for the given cpu (old api)
309 * @cpu - the cpuid as returned by get_cpu()
310 */
311u8 dca_get_tag(int cpu)
312{
313 struct device *dev = NULL;
314
315 return dca_common_get_tag(dev, cpu);
316}
317EXPORT_SYMBOL_GPL(dca_get_tag);
318
319/**
320 * alloc_dca_provider - get data struct for describing a dca provider
321 * @ops - pointer to struct of dca operation function pointers
322 * @priv_size - size of extra mem to be added for provider's needs
323 */
324struct dca_provider *alloc_dca_provider(const struct dca_ops *ops,
325 int priv_size)
326{
327 struct dca_provider *dca;
328 int alloc_size;
329
330 alloc_size = (sizeof(*dca) + priv_size);
331 dca = kzalloc(alloc_size, GFP_KERNEL);
332 if (!dca)
333 return NULL;
334 dca->ops = ops;
335
336 return dca;
337}
338EXPORT_SYMBOL_GPL(alloc_dca_provider);
339
340/**
341 * free_dca_provider - release the dca provider data struct
342 * @ops - pointer to struct of dca operation function pointers
343 * @priv_size - size of extra mem to be added for provider's needs
344 */
345void free_dca_provider(struct dca_provider *dca)
346{
347 kfree(dca);
348}
349EXPORT_SYMBOL_GPL(free_dca_provider);
350
351/**
352 * register_dca_provider - register a dca provider
353 * @dca - struct created by alloc_dca_provider()
354 * @dev - device providing dca services
355 */
356int register_dca_provider(struct dca_provider *dca, struct device *dev)
357{
358 int err;
359 unsigned long flags;
360 struct dca_domain *domain, *newdomain = NULL;
361
362 raw_spin_lock_irqsave(&dca_lock, flags);
363 if (dca_providers_blocked) {
364 raw_spin_unlock_irqrestore(&dca_lock, flags);
365 return -ENODEV;
366 }
367 raw_spin_unlock_irqrestore(&dca_lock, flags);
368
369 err = dca_sysfs_add_provider(dca, dev);
370 if (err)
371 return err;
372
373 raw_spin_lock_irqsave(&dca_lock, flags);
374 domain = dca_get_domain(dev);
375 if (!domain) {
376 struct pci_bus *rc;
377
378 if (dca_providers_blocked) {
379 raw_spin_unlock_irqrestore(&dca_lock, flags);
380 dca_sysfs_remove_provider(dca);
381 unregister_dca_providers();
382 return -ENODEV;
383 }
384
385 raw_spin_unlock_irqrestore(&dca_lock, flags);
386 rc = dca_pci_rc_from_dev(dev);
387 newdomain = dca_allocate_domain(rc);
388 if (!newdomain)
389 return -ENODEV;
390 raw_spin_lock_irqsave(&dca_lock, flags);
391 /* Recheck, we might have raced after dropping the lock */
392 domain = dca_get_domain(dev);
393 if (!domain) {
394 domain = newdomain;
395 newdomain = NULL;
396 list_add(&domain->node, &dca_domains);
397 }
398 }
399 list_add(&dca->node, &domain->dca_providers);
400 raw_spin_unlock_irqrestore(&dca_lock, flags);
401
402 blocking_notifier_call_chain(&dca_provider_chain,
403 DCA_PROVIDER_ADD, NULL);
404 kfree(newdomain);
405 return 0;
406}
407EXPORT_SYMBOL_GPL(register_dca_provider);
408
409/**
410 * unregister_dca_provider - remove a dca provider
411 * @dca - struct created by alloc_dca_provider()
412 */
413void unregister_dca_provider(struct dca_provider *dca, struct device *dev)
414{
415 unsigned long flags;
416 struct pci_bus *pci_rc;
417 struct dca_domain *domain;
418
419 blocking_notifier_call_chain(&dca_provider_chain,
420 DCA_PROVIDER_REMOVE, NULL);
421
422 raw_spin_lock_irqsave(&dca_lock, flags);
423
424 if (list_empty(&dca_domains)) {
425 raw_spin_unlock_irqrestore(&dca_lock, flags);
426 return;
427 }
428
429 list_del(&dca->node);
430
431 pci_rc = dca_pci_rc_from_dev(dev);
432 domain = dca_find_domain(pci_rc);
433 if (list_empty(&domain->dca_providers))
434 dca_free_domain(domain);
435
436 raw_spin_unlock_irqrestore(&dca_lock, flags);
437
438 dca_sysfs_remove_provider(dca);
439}
440EXPORT_SYMBOL_GPL(unregister_dca_provider);
441
442/**
443 * dca_register_notify - register a client's notifier callback
444 */
445void dca_register_notify(struct notifier_block *nb)
446{
447 blocking_notifier_chain_register(&dca_provider_chain, nb);
448}
449EXPORT_SYMBOL_GPL(dca_register_notify);
450
451/**
452 * dca_unregister_notify - remove a client's notifier callback
453 */
454void dca_unregister_notify(struct notifier_block *nb)
455{
456 blocking_notifier_chain_unregister(&dca_provider_chain, nb);
457}
458EXPORT_SYMBOL_GPL(dca_unregister_notify);
459
460static int __init dca_init(void)
461{
462 pr_info("dca service started, version %s\n", DCA_VERSION);
463 return dca_sysfs_init();
464}
465
466static void __exit dca_exit(void)
467{
468 dca_sysfs_exit();
469}
470
471arch_initcall(dca_init);
472module_exit(dca_exit);
473
474