1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Copyright(c) 2007 - 2009 Intel Corporation. All rights reserved. |
4 | */ |
5 | |
6 | /* |
7 | * This driver supports an interface for DCA clients and providers to meet. |
8 | */ |
9 | |
10 | #include <linux/kernel.h> |
11 | #include <linux/notifier.h> |
12 | #include <linux/device.h> |
13 | #include <linux/dca.h> |
14 | #include <linux/slab.h> |
15 | #include <linux/module.h> |
16 | |
17 | #define DCA_VERSION "1.12.1" |
18 | |
19 | MODULE_VERSION(DCA_VERSION); |
20 | MODULE_LICENSE("GPL" ); |
21 | MODULE_AUTHOR("Intel Corporation" ); |
22 | |
23 | static DEFINE_RAW_SPINLOCK(dca_lock); |
24 | |
25 | static LIST_HEAD(dca_domains); |
26 | |
27 | static BLOCKING_NOTIFIER_HEAD(dca_provider_chain); |
28 | |
29 | static int dca_providers_blocked; |
30 | |
31 | static struct pci_bus *dca_pci_rc_from_dev(struct device *dev) |
32 | { |
33 | struct pci_dev *pdev = to_pci_dev(dev); |
34 | struct pci_bus *bus = pdev->bus; |
35 | |
36 | while (bus->parent) |
37 | bus = bus->parent; |
38 | |
39 | return bus; |
40 | } |
41 | |
42 | static struct dca_domain *dca_allocate_domain(struct pci_bus *rc) |
43 | { |
44 | struct dca_domain *domain; |
45 | |
46 | domain = kzalloc(size: sizeof(*domain), GFP_NOWAIT); |
47 | if (!domain) |
48 | return NULL; |
49 | |
50 | INIT_LIST_HEAD(list: &domain->dca_providers); |
51 | domain->pci_rc = rc; |
52 | |
53 | return domain; |
54 | } |
55 | |
56 | static void dca_free_domain(struct dca_domain *domain) |
57 | { |
58 | list_del(entry: &domain->node); |
59 | kfree(objp: domain); |
60 | } |
61 | |
62 | static int dca_provider_ioat_ver_3_0(struct device *dev) |
63 | { |
64 | struct pci_dev *pdev = to_pci_dev(dev); |
65 | |
66 | return ((pdev->vendor == PCI_VENDOR_ID_INTEL) && |
67 | ((pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG0) || |
68 | (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG1) || |
69 | (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG2) || |
70 | (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG3) || |
71 | (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG4) || |
72 | (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG5) || |
73 | (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG6) || |
74 | (pdev->device == PCI_DEVICE_ID_INTEL_IOAT_TBG7))); |
75 | } |
76 | |
77 | static void unregister_dca_providers(void) |
78 | { |
79 | struct dca_provider *dca, *_dca; |
80 | struct list_head unregistered_providers; |
81 | struct dca_domain *domain; |
82 | unsigned long flags; |
83 | |
84 | blocking_notifier_call_chain(nh: &dca_provider_chain, |
85 | DCA_PROVIDER_REMOVE, NULL); |
86 | |
87 | INIT_LIST_HEAD(list: &unregistered_providers); |
88 | |
89 | raw_spin_lock_irqsave(&dca_lock, flags); |
90 | |
91 | if (list_empty(head: &dca_domains)) { |
92 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
93 | return; |
94 | } |
95 | |
96 | /* at this point only one domain in the list is expected */ |
97 | domain = list_first_entry(&dca_domains, struct dca_domain, node); |
98 | |
99 | list_for_each_entry_safe(dca, _dca, &domain->dca_providers, node) |
100 | list_move(list: &dca->node, head: &unregistered_providers); |
101 | |
102 | dca_free_domain(domain); |
103 | |
104 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
105 | |
106 | list_for_each_entry_safe(dca, _dca, &unregistered_providers, node) { |
107 | dca_sysfs_remove_provider(dca); |
108 | list_del(entry: &dca->node); |
109 | } |
110 | } |
111 | |
112 | static struct dca_domain *dca_find_domain(struct pci_bus *rc) |
113 | { |
114 | struct dca_domain *domain; |
115 | |
116 | list_for_each_entry(domain, &dca_domains, node) |
117 | if (domain->pci_rc == rc) |
118 | return domain; |
119 | |
120 | return NULL; |
121 | } |
122 | |
123 | static struct dca_domain *dca_get_domain(struct device *dev) |
124 | { |
125 | struct pci_bus *rc; |
126 | struct dca_domain *domain; |
127 | |
128 | rc = dca_pci_rc_from_dev(dev); |
129 | domain = dca_find_domain(rc); |
130 | |
131 | if (!domain) { |
132 | if (dca_provider_ioat_ver_3_0(dev) && !list_empty(head: &dca_domains)) |
133 | dca_providers_blocked = 1; |
134 | } |
135 | |
136 | return domain; |
137 | } |
138 | |
139 | static struct dca_provider *dca_find_provider_by_dev(struct device *dev) |
140 | { |
141 | struct dca_provider *dca; |
142 | struct pci_bus *rc; |
143 | struct dca_domain *domain; |
144 | |
145 | if (dev) { |
146 | rc = dca_pci_rc_from_dev(dev); |
147 | domain = dca_find_domain(rc); |
148 | if (!domain) |
149 | return NULL; |
150 | } else { |
151 | if (!list_empty(head: &dca_domains)) |
152 | domain = list_first_entry(&dca_domains, |
153 | struct dca_domain, |
154 | node); |
155 | else |
156 | return NULL; |
157 | } |
158 | |
159 | list_for_each_entry(dca, &domain->dca_providers, node) |
160 | if ((!dev) || (dca->ops->dev_managed(dca, dev))) |
161 | return dca; |
162 | |
163 | return NULL; |
164 | } |
165 | |
166 | /** |
167 | * dca_add_requester - add a dca client to the list |
168 | * @dev - the device that wants dca service |
169 | */ |
170 | int dca_add_requester(struct device *dev) |
171 | { |
172 | struct dca_provider *dca; |
173 | int err, slot = -ENODEV; |
174 | unsigned long flags; |
175 | struct pci_bus *pci_rc; |
176 | struct dca_domain *domain; |
177 | |
178 | if (!dev) |
179 | return -EFAULT; |
180 | |
181 | raw_spin_lock_irqsave(&dca_lock, flags); |
182 | |
183 | /* check if the requester has not been added already */ |
184 | dca = dca_find_provider_by_dev(dev); |
185 | if (dca) { |
186 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
187 | return -EEXIST; |
188 | } |
189 | |
190 | pci_rc = dca_pci_rc_from_dev(dev); |
191 | domain = dca_find_domain(rc: pci_rc); |
192 | if (!domain) { |
193 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
194 | return -ENODEV; |
195 | } |
196 | |
197 | list_for_each_entry(dca, &domain->dca_providers, node) { |
198 | slot = dca->ops->add_requester(dca, dev); |
199 | if (slot >= 0) |
200 | break; |
201 | } |
202 | |
203 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
204 | |
205 | if (slot < 0) |
206 | return slot; |
207 | |
208 | err = dca_sysfs_add_req(dca, dev, slot); |
209 | if (err) { |
210 | raw_spin_lock_irqsave(&dca_lock, flags); |
211 | if (dca == dca_find_provider_by_dev(dev)) |
212 | dca->ops->remove_requester(dca, dev); |
213 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
214 | return err; |
215 | } |
216 | |
217 | return 0; |
218 | } |
219 | EXPORT_SYMBOL_GPL(dca_add_requester); |
220 | |
221 | /** |
222 | * dca_remove_requester - remove a dca client from the list |
223 | * @dev - the device that wants dca service |
224 | */ |
225 | int dca_remove_requester(struct device *dev) |
226 | { |
227 | struct dca_provider *dca; |
228 | int slot; |
229 | unsigned long flags; |
230 | |
231 | if (!dev) |
232 | return -EFAULT; |
233 | |
234 | raw_spin_lock_irqsave(&dca_lock, flags); |
235 | dca = dca_find_provider_by_dev(dev); |
236 | if (!dca) { |
237 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
238 | return -ENODEV; |
239 | } |
240 | slot = dca->ops->remove_requester(dca, dev); |
241 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
242 | |
243 | if (slot < 0) |
244 | return slot; |
245 | |
246 | dca_sysfs_remove_req(dca, slot); |
247 | |
248 | return 0; |
249 | } |
250 | EXPORT_SYMBOL_GPL(dca_remove_requester); |
251 | |
252 | /** |
253 | * dca_common_get_tag - return the dca tag (serves both new and old api) |
254 | * @dev - the device that wants dca service |
255 | * @cpu - the cpuid as returned by get_cpu() |
256 | */ |
257 | static u8 dca_common_get_tag(struct device *dev, int cpu) |
258 | { |
259 | struct dca_provider *dca; |
260 | u8 tag; |
261 | unsigned long flags; |
262 | |
263 | raw_spin_lock_irqsave(&dca_lock, flags); |
264 | |
265 | dca = dca_find_provider_by_dev(dev); |
266 | if (!dca) { |
267 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
268 | return -ENODEV; |
269 | } |
270 | tag = dca->ops->get_tag(dca, dev, cpu); |
271 | |
272 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
273 | return tag; |
274 | } |
275 | |
276 | /** |
277 | * dca3_get_tag - return the dca tag to the requester device |
278 | * for the given cpu (new api) |
279 | * @dev - the device that wants dca service |
280 | * @cpu - the cpuid as returned by get_cpu() |
281 | */ |
282 | u8 dca3_get_tag(struct device *dev, int cpu) |
283 | { |
284 | if (!dev) |
285 | return -EFAULT; |
286 | |
287 | return dca_common_get_tag(dev, cpu); |
288 | } |
289 | EXPORT_SYMBOL_GPL(dca3_get_tag); |
290 | |
291 | /** |
292 | * dca_get_tag - return the dca tag for the given cpu (old api) |
293 | * @cpu - the cpuid as returned by get_cpu() |
294 | */ |
295 | u8 dca_get_tag(int cpu) |
296 | { |
297 | return dca_common_get_tag(NULL, cpu); |
298 | } |
299 | EXPORT_SYMBOL_GPL(dca_get_tag); |
300 | |
301 | /** |
302 | * alloc_dca_provider - get data struct for describing a dca provider |
303 | * @ops - pointer to struct of dca operation function pointers |
304 | * @priv_size - size of extra mem to be added for provider's needs |
305 | */ |
306 | struct dca_provider *alloc_dca_provider(const struct dca_ops *ops, |
307 | int priv_size) |
308 | { |
309 | struct dca_provider *dca; |
310 | int alloc_size; |
311 | |
312 | alloc_size = (sizeof(*dca) + priv_size); |
313 | dca = kzalloc(size: alloc_size, GFP_KERNEL); |
314 | if (!dca) |
315 | return NULL; |
316 | dca->ops = ops; |
317 | |
318 | return dca; |
319 | } |
320 | EXPORT_SYMBOL_GPL(alloc_dca_provider); |
321 | |
322 | /** |
323 | * free_dca_provider - release the dca provider data struct |
324 | * @ops - pointer to struct of dca operation function pointers |
325 | * @priv_size - size of extra mem to be added for provider's needs |
326 | */ |
327 | void free_dca_provider(struct dca_provider *dca) |
328 | { |
329 | kfree(objp: dca); |
330 | } |
331 | EXPORT_SYMBOL_GPL(free_dca_provider); |
332 | |
333 | /** |
334 | * register_dca_provider - register a dca provider |
335 | * @dca - struct created by alloc_dca_provider() |
336 | * @dev - device providing dca services |
337 | */ |
338 | int register_dca_provider(struct dca_provider *dca, struct device *dev) |
339 | { |
340 | int err; |
341 | unsigned long flags; |
342 | struct dca_domain *domain, *newdomain = NULL; |
343 | |
344 | raw_spin_lock_irqsave(&dca_lock, flags); |
345 | if (dca_providers_blocked) { |
346 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
347 | return -ENODEV; |
348 | } |
349 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
350 | |
351 | err = dca_sysfs_add_provider(dca, dev); |
352 | if (err) |
353 | return err; |
354 | |
355 | raw_spin_lock_irqsave(&dca_lock, flags); |
356 | domain = dca_get_domain(dev); |
357 | if (!domain) { |
358 | struct pci_bus *rc; |
359 | |
360 | if (dca_providers_blocked) { |
361 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
362 | dca_sysfs_remove_provider(dca); |
363 | unregister_dca_providers(); |
364 | return -ENODEV; |
365 | } |
366 | |
367 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
368 | rc = dca_pci_rc_from_dev(dev); |
369 | newdomain = dca_allocate_domain(rc); |
370 | if (!newdomain) |
371 | return -ENODEV; |
372 | raw_spin_lock_irqsave(&dca_lock, flags); |
373 | /* Recheck, we might have raced after dropping the lock */ |
374 | domain = dca_get_domain(dev); |
375 | if (!domain) { |
376 | domain = newdomain; |
377 | newdomain = NULL; |
378 | list_add(new: &domain->node, head: &dca_domains); |
379 | } |
380 | } |
381 | list_add(new: &dca->node, head: &domain->dca_providers); |
382 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
383 | |
384 | blocking_notifier_call_chain(nh: &dca_provider_chain, |
385 | DCA_PROVIDER_ADD, NULL); |
386 | kfree(objp: newdomain); |
387 | return 0; |
388 | } |
389 | EXPORT_SYMBOL_GPL(register_dca_provider); |
390 | |
391 | /** |
392 | * unregister_dca_provider - remove a dca provider |
393 | * @dca - struct created by alloc_dca_provider() |
394 | */ |
395 | void unregister_dca_provider(struct dca_provider *dca, struct device *dev) |
396 | { |
397 | unsigned long flags; |
398 | struct pci_bus *pci_rc; |
399 | struct dca_domain *domain; |
400 | |
401 | blocking_notifier_call_chain(nh: &dca_provider_chain, |
402 | DCA_PROVIDER_REMOVE, NULL); |
403 | |
404 | raw_spin_lock_irqsave(&dca_lock, flags); |
405 | |
406 | if (list_empty(head: &dca_domains)) { |
407 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
408 | return; |
409 | } |
410 | |
411 | list_del(entry: &dca->node); |
412 | |
413 | pci_rc = dca_pci_rc_from_dev(dev); |
414 | domain = dca_find_domain(rc: pci_rc); |
415 | if (list_empty(head: &domain->dca_providers)) |
416 | dca_free_domain(domain); |
417 | |
418 | raw_spin_unlock_irqrestore(&dca_lock, flags); |
419 | |
420 | dca_sysfs_remove_provider(dca); |
421 | } |
422 | EXPORT_SYMBOL_GPL(unregister_dca_provider); |
423 | |
424 | /** |
425 | * dca_register_notify - register a client's notifier callback |
426 | */ |
427 | void dca_register_notify(struct notifier_block *nb) |
428 | { |
429 | blocking_notifier_chain_register(nh: &dca_provider_chain, nb); |
430 | } |
431 | EXPORT_SYMBOL_GPL(dca_register_notify); |
432 | |
433 | /** |
434 | * dca_unregister_notify - remove a client's notifier callback |
435 | */ |
436 | void dca_unregister_notify(struct notifier_block *nb) |
437 | { |
438 | blocking_notifier_chain_unregister(nh: &dca_provider_chain, nb); |
439 | } |
440 | EXPORT_SYMBOL_GPL(dca_unregister_notify); |
441 | |
442 | static int __init dca_init(void) |
443 | { |
444 | pr_info("dca service started, version %s\n" , DCA_VERSION); |
445 | return dca_sysfs_init(); |
446 | } |
447 | |
448 | static void __exit dca_exit(void) |
449 | { |
450 | dca_sysfs_exit(); |
451 | } |
452 | |
453 | arch_initcall(dca_init); |
454 | module_exit(dca_exit); |
455 | |
456 | |