Commit | Line | Data |
---|---|---|
f73f8173 AW |
1 | /* |
2 | * IRQ offload/bypass manager | |
3 | * | |
4 | * Copyright (C) 2015 Red Hat, Inc. | |
5 | * Copyright (c) 2015 Linaro Ltd. | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * Various virtualization hardware acceleration techniques allow bypassing or | |
12 | * offloading interrupts received from devices around the host kernel. Posted | |
13 | * Interrupts on Intel VT-d systems can allow interrupts to be received | |
14 | * directly by a virtual machine. ARM IRQ Forwarding allows forwarded physical | |
15 | * interrupts to be directly deactivated by the guest. This manager allows | |
16 | * interrupt producers and consumers to find each other to enable this sort of | |
17 | * bypass. | |
18 | */ | |
19 | ||
20 | #include <linux/irqbypass.h> | |
21 | #include <linux/list.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/mutex.h> | |
24 | ||
25 | MODULE_LICENSE("GPL v2"); | |
26 | MODULE_DESCRIPTION("IRQ bypass manager utility module"); | |
27 | ||
28 | static LIST_HEAD(producers); | |
29 | static LIST_HEAD(consumers); | |
30 | static DEFINE_MUTEX(lock); | |
31 | ||
32 | /* @lock must be held when calling connect */ | |
33 | static int __connect(struct irq_bypass_producer *prod, | |
34 | struct irq_bypass_consumer *cons) | |
35 | { | |
36 | int ret = 0; | |
37 | ||
38 | if (prod->stop) | |
39 | prod->stop(prod); | |
40 | if (cons->stop) | |
41 | cons->stop(cons); | |
42 | ||
43 | if (prod->add_consumer) | |
44 | ret = prod->add_consumer(prod, cons); | |
45 | ||
46 | if (!ret) { | |
47 | ret = cons->add_producer(cons, prod); | |
48 | if (ret && prod->del_consumer) | |
49 | prod->del_consumer(prod, cons); | |
50 | } | |
51 | ||
52 | if (cons->start) | |
53 | cons->start(cons); | |
54 | if (prod->start) | |
55 | prod->start(prod); | |
56 | ||
57 | return ret; | |
58 | } | |
59 | ||
60 | /* @lock must be held when calling disconnect */ | |
61 | static void __disconnect(struct irq_bypass_producer *prod, | |
62 | struct irq_bypass_consumer *cons) | |
63 | { | |
64 | if (prod->stop) | |
65 | prod->stop(prod); | |
66 | if (cons->stop) | |
67 | cons->stop(cons); | |
68 | ||
69 | cons->del_producer(cons, prod); | |
70 | ||
71 | if (prod->del_consumer) | |
72 | prod->del_consumer(prod, cons); | |
73 | ||
74 | if (cons->start) | |
75 | cons->start(cons); | |
76 | if (prod->start) | |
77 | prod->start(prod); | |
78 | } | |
79 | ||
80 | /** | |
81 | * irq_bypass_register_producer - register IRQ bypass producer | |
82 | * @producer: pointer to producer structure | |
83 | * | |
84 | * Add the provided IRQ producer to the list of producers and connect | |
85 | * with any matching token found on the IRQ consumers list. | |
86 | */ | |
87 | int irq_bypass_register_producer(struct irq_bypass_producer *producer) | |
88 | { | |
89 | struct irq_bypass_producer *tmp; | |
90 | struct irq_bypass_consumer *consumer; | |
91 | ||
b52f3ed0 AW |
92 | if (!producer->token) |
93 | return -EINVAL; | |
94 | ||
f73f8173 AW |
95 | might_sleep(); |
96 | ||
97 | if (!try_module_get(THIS_MODULE)) | |
98 | return -ENODEV; | |
99 | ||
100 | mutex_lock(&lock); | |
101 | ||
102 | list_for_each_entry(tmp, &producers, node) { | |
103 | if (tmp->token == producer->token) { | |
104 | mutex_unlock(&lock); | |
105 | module_put(THIS_MODULE); | |
106 | return -EBUSY; | |
107 | } | |
108 | } | |
109 | ||
110 | list_for_each_entry(consumer, &consumers, node) { | |
111 | if (consumer->token == producer->token) { | |
112 | int ret = __connect(producer, consumer); | |
113 | if (ret) { | |
114 | mutex_unlock(&lock); | |
115 | module_put(THIS_MODULE); | |
116 | return ret; | |
117 | } | |
118 | break; | |
119 | } | |
120 | } | |
121 | ||
122 | list_add(&producer->node, &producers); | |
123 | ||
124 | mutex_unlock(&lock); | |
125 | ||
126 | return 0; | |
127 | } | |
128 | EXPORT_SYMBOL_GPL(irq_bypass_register_producer); | |
129 | ||
130 | /** | |
131 | * irq_bypass_unregister_producer - unregister IRQ bypass producer | |
132 | * @producer: pointer to producer structure | |
133 | * | |
134 | * Remove a previously registered IRQ producer from the list of producers | |
135 | * and disconnect it from any connected IRQ consumer. | |
136 | */ | |
137 | void irq_bypass_unregister_producer(struct irq_bypass_producer *producer) | |
138 | { | |
139 | struct irq_bypass_producer *tmp; | |
140 | struct irq_bypass_consumer *consumer; | |
141 | ||
b52f3ed0 AW |
142 | if (!producer->token) |
143 | return; | |
144 | ||
f73f8173 AW |
145 | might_sleep(); |
146 | ||
147 | if (!try_module_get(THIS_MODULE)) | |
148 | return; /* nothing in the list anyway */ | |
149 | ||
150 | mutex_lock(&lock); | |
151 | ||
152 | list_for_each_entry(tmp, &producers, node) { | |
153 | if (tmp->token != producer->token) | |
154 | continue; | |
155 | ||
156 | list_for_each_entry(consumer, &consumers, node) { | |
157 | if (consumer->token == producer->token) { | |
158 | __disconnect(producer, consumer); | |
159 | break; | |
160 | } | |
161 | } | |
162 | ||
163 | list_del(&producer->node); | |
164 | module_put(THIS_MODULE); | |
165 | break; | |
166 | } | |
167 | ||
168 | mutex_unlock(&lock); | |
169 | ||
170 | module_put(THIS_MODULE); | |
171 | } | |
172 | EXPORT_SYMBOL_GPL(irq_bypass_unregister_producer); | |
173 | ||
174 | /** | |
175 | * irq_bypass_register_consumer - register IRQ bypass consumer | |
176 | * @consumer: pointer to consumer structure | |
177 | * | |
178 | * Add the provided IRQ consumer to the list of consumers and connect | |
179 | * with any matching token found on the IRQ producer list. | |
180 | */ | |
181 | int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer) | |
182 | { | |
183 | struct irq_bypass_consumer *tmp; | |
184 | struct irq_bypass_producer *producer; | |
185 | ||
b52f3ed0 AW |
186 | if (!consumer->token || |
187 | !consumer->add_producer || !consumer->del_producer) | |
f73f8173 AW |
188 | return -EINVAL; |
189 | ||
190 | might_sleep(); | |
191 | ||
192 | if (!try_module_get(THIS_MODULE)) | |
193 | return -ENODEV; | |
194 | ||
195 | mutex_lock(&lock); | |
196 | ||
197 | list_for_each_entry(tmp, &consumers, node) { | |
198 | if (tmp->token == consumer->token) { | |
199 | mutex_unlock(&lock); | |
200 | module_put(THIS_MODULE); | |
201 | return -EBUSY; | |
202 | } | |
203 | } | |
204 | ||
205 | list_for_each_entry(producer, &producers, node) { | |
206 | if (producer->token == consumer->token) { | |
207 | int ret = __connect(producer, consumer); | |
208 | if (ret) { | |
209 | mutex_unlock(&lock); | |
210 | module_put(THIS_MODULE); | |
211 | return ret; | |
212 | } | |
213 | break; | |
214 | } | |
215 | } | |
216 | ||
217 | list_add(&consumer->node, &consumers); | |
218 | ||
219 | mutex_unlock(&lock); | |
220 | ||
221 | return 0; | |
222 | } | |
223 | EXPORT_SYMBOL_GPL(irq_bypass_register_consumer); | |
224 | ||
225 | /** | |
226 | * irq_bypass_unregister_consumer - unregister IRQ bypass consumer | |
227 | * @consumer: pointer to consumer structure | |
228 | * | |
229 | * Remove a previously registered IRQ consumer from the list of consumers | |
230 | * and disconnect it from any connected IRQ producer. | |
231 | */ | |
232 | void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer) | |
233 | { | |
234 | struct irq_bypass_consumer *tmp; | |
235 | struct irq_bypass_producer *producer; | |
236 | ||
b52f3ed0 AW |
237 | if (!consumer->token) |
238 | return; | |
239 | ||
f73f8173 AW |
240 | might_sleep(); |
241 | ||
242 | if (!try_module_get(THIS_MODULE)) | |
243 | return; /* nothing in the list anyway */ | |
244 | ||
245 | mutex_lock(&lock); | |
246 | ||
247 | list_for_each_entry(tmp, &consumers, node) { | |
248 | if (tmp->token != consumer->token) | |
249 | continue; | |
250 | ||
251 | list_for_each_entry(producer, &producers, node) { | |
252 | if (producer->token == consumer->token) { | |
253 | __disconnect(producer, consumer); | |
254 | break; | |
255 | } | |
256 | } | |
257 | ||
258 | list_del(&consumer->node); | |
259 | module_put(THIS_MODULE); | |
260 | break; | |
261 | } | |
262 | ||
263 | mutex_unlock(&lock); | |
264 | ||
265 | module_put(THIS_MODULE); | |
266 | } | |
267 | EXPORT_SYMBOL_GPL(irq_bypass_unregister_consumer); |