Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/kernel/irq/manage.c | |
3 | * | |
a34db9b2 IM |
4 | * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar |
5 | * Copyright (C) 2005-2006 Thomas Gleixner | |
1da177e4 LT |
6 | * |
7 | * This file contains driver APIs to the irq subsystem. | |
8 | */ | |
9 | ||
10 | #include <linux/irq.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/random.h> | |
13 | #include <linux/interrupt.h> | |
14 | ||
15 | #include "internals.h" | |
16 | ||
17 | #ifdef CONFIG_SMP | |
18 | ||
1da177e4 LT |
19 | /** |
20 | * synchronize_irq - wait for pending IRQ handlers (on other CPUs) | |
1e5d5331 | 21 | * @irq: interrupt number to wait for |
1da177e4 LT |
22 | * |
23 | * This function waits for any pending IRQ handlers for this interrupt | |
24 | * to complete before returning. If you use this function while | |
25 | * holding a resource the IRQ handler may need you will deadlock. | |
26 | * | |
27 | * This function may be called - with care - from IRQ context. | |
28 | */ | |
29 | void synchronize_irq(unsigned int irq) | |
30 | { | |
31 | struct irq_desc *desc = irq_desc + irq; | |
32 | ||
c2b5a251 MW |
33 | if (irq >= NR_IRQS) |
34 | return; | |
35 | ||
1da177e4 LT |
36 | while (desc->status & IRQ_INPROGRESS) |
37 | cpu_relax(); | |
38 | } | |
1da177e4 LT |
39 | EXPORT_SYMBOL(synchronize_irq); |
40 | ||
41 | #endif | |
42 | ||
43 | /** | |
44 | * disable_irq_nosync - disable an irq without waiting | |
45 | * @irq: Interrupt to disable | |
46 | * | |
47 | * Disable the selected interrupt line. Disables and Enables are | |
48 | * nested. | |
49 | * Unlike disable_irq(), this function does not ensure existing | |
50 | * instances of the IRQ handler have completed before returning. | |
51 | * | |
52 | * This function may be called from IRQ context. | |
53 | */ | |
54 | void disable_irq_nosync(unsigned int irq) | |
55 | { | |
34ffdb72 | 56 | struct irq_desc *desc = irq_desc + irq; |
1da177e4 LT |
57 | unsigned long flags; |
58 | ||
c2b5a251 MW |
59 | if (irq >= NR_IRQS) |
60 | return; | |
61 | ||
1da177e4 LT |
62 | spin_lock_irqsave(&desc->lock, flags); |
63 | if (!desc->depth++) { | |
64 | desc->status |= IRQ_DISABLED; | |
d1bef4ed | 65 | desc->chip->disable(irq); |
1da177e4 LT |
66 | } |
67 | spin_unlock_irqrestore(&desc->lock, flags); | |
68 | } | |
1da177e4 LT |
69 | EXPORT_SYMBOL(disable_irq_nosync); |
70 | ||
71 | /** | |
72 | * disable_irq - disable an irq and wait for completion | |
73 | * @irq: Interrupt to disable | |
74 | * | |
75 | * Disable the selected interrupt line. Enables and Disables are | |
76 | * nested. | |
77 | * This function waits for any pending IRQ handlers for this interrupt | |
78 | * to complete before returning. If you use this function while | |
79 | * holding a resource the IRQ handler may need you will deadlock. | |
80 | * | |
81 | * This function may be called - with care - from IRQ context. | |
82 | */ | |
83 | void disable_irq(unsigned int irq) | |
84 | { | |
34ffdb72 | 85 | struct irq_desc *desc = irq_desc + irq; |
1da177e4 | 86 | |
c2b5a251 MW |
87 | if (irq >= NR_IRQS) |
88 | return; | |
89 | ||
1da177e4 LT |
90 | disable_irq_nosync(irq); |
91 | if (desc->action) | |
92 | synchronize_irq(irq); | |
93 | } | |
1da177e4 LT |
94 | EXPORT_SYMBOL(disable_irq); |
95 | ||
96 | /** | |
97 | * enable_irq - enable handling of an irq | |
98 | * @irq: Interrupt to enable | |
99 | * | |
100 | * Undoes the effect of one call to disable_irq(). If this | |
101 | * matches the last disable, processing of interrupts on this | |
102 | * IRQ line is re-enabled. | |
103 | * | |
104 | * This function may be called from IRQ context. | |
105 | */ | |
106 | void enable_irq(unsigned int irq) | |
107 | { | |
34ffdb72 | 108 | struct irq_desc *desc = irq_desc + irq; |
1da177e4 LT |
109 | unsigned long flags; |
110 | ||
c2b5a251 MW |
111 | if (irq >= NR_IRQS) |
112 | return; | |
113 | ||
1da177e4 LT |
114 | spin_lock_irqsave(&desc->lock, flags); |
115 | switch (desc->depth) { | |
116 | case 0: | |
e8c4b9d0 | 117 | printk(KERN_WARNING "Unbalanced enable for IRQ %d\n", irq); |
1da177e4 LT |
118 | WARN_ON(1); |
119 | break; | |
120 | case 1: { | |
3418d724 TG |
121 | unsigned int status = desc->status & ~IRQ_DISABLED; |
122 | ||
123 | /* Prevent probing on this irq: */ | |
124 | desc->status = status | IRQ_NOPROBE; | |
a4633adc | 125 | check_irq_resend(desc, irq); |
1da177e4 LT |
126 | /* fall-through */ |
127 | } | |
128 | default: | |
129 | desc->depth--; | |
130 | } | |
131 | spin_unlock_irqrestore(&desc->lock, flags); | |
132 | } | |
1da177e4 LT |
133 | EXPORT_SYMBOL(enable_irq); |
134 | ||
ba9a2331 TG |
135 | /** |
136 | * set_irq_wake - control irq power management wakeup | |
137 | * @irq: interrupt to control | |
138 | * @on: enable/disable power management wakeup | |
139 | * | |
140 | * Enable/disable power management wakeup mode | |
141 | */ | |
142 | int set_irq_wake(unsigned int irq, unsigned int on) | |
143 | { | |
144 | struct irq_desc *desc = irq_desc + irq; | |
145 | unsigned long flags; | |
146 | int ret = -ENXIO; | |
147 | ||
148 | spin_lock_irqsave(&desc->lock, flags); | |
149 | if (desc->chip->set_wake) | |
150 | ret = desc->chip->set_wake(irq, on); | |
151 | spin_unlock_irqrestore(&desc->lock, flags); | |
152 | return ret; | |
153 | } | |
154 | EXPORT_SYMBOL(set_irq_wake); | |
155 | ||
1da177e4 LT |
156 | /* |
157 | * Internal function that tells the architecture code whether a | |
158 | * particular irq has been exclusively allocated or is available | |
159 | * for driver use. | |
160 | */ | |
161 | int can_request_irq(unsigned int irq, unsigned long irqflags) | |
162 | { | |
163 | struct irqaction *action; | |
164 | ||
6550c775 | 165 | if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST) |
1da177e4 LT |
166 | return 0; |
167 | ||
168 | action = irq_desc[irq].action; | |
169 | if (action) | |
3cca53b0 | 170 | if (irqflags & action->flags & IRQF_SHARED) |
1da177e4 LT |
171 | action = NULL; |
172 | ||
173 | return !action; | |
174 | } | |
175 | ||
6a6de9ef TG |
176 | void compat_irq_chip_set_default_handler(struct irq_desc *desc) |
177 | { | |
178 | /* | |
179 | * If the architecture still has not overriden | |
180 | * the flow handler then zap the default. This | |
181 | * should catch incorrect flow-type setting. | |
182 | */ | |
183 | if (desc->handle_irq == &handle_bad_irq) | |
184 | desc->handle_irq = NULL; | |
185 | } | |
186 | ||
1da177e4 LT |
187 | /* |
188 | * Internal function to register an irqaction - typically used to | |
189 | * allocate special interrupts that are part of the architecture. | |
190 | */ | |
06fcb0c6 | 191 | int setup_irq(unsigned int irq, struct irqaction *new) |
1da177e4 LT |
192 | { |
193 | struct irq_desc *desc = irq_desc + irq; | |
194 | struct irqaction *old, **p; | |
195 | unsigned long flags; | |
196 | int shared = 0; | |
197 | ||
c2b5a251 MW |
198 | if (irq >= NR_IRQS) |
199 | return -EINVAL; | |
200 | ||
f1c2662c | 201 | if (desc->chip == &no_irq_chip) |
1da177e4 LT |
202 | return -ENOSYS; |
203 | /* | |
204 | * Some drivers like serial.c use request_irq() heavily, | |
205 | * so we have to be careful not to interfere with a | |
206 | * running system. | |
207 | */ | |
3cca53b0 | 208 | if (new->flags & IRQF_SAMPLE_RANDOM) { |
1da177e4 LT |
209 | /* |
210 | * This function might sleep, we want to call it first, | |
211 | * outside of the atomic block. | |
212 | * Yes, this might clear the entropy pool if the wrong | |
213 | * driver is attempted to be loaded, without actually | |
214 | * installing a new handler, but is this really a problem, | |
215 | * only the sysadmin is able to do this. | |
216 | */ | |
217 | rand_initialize_irq(irq); | |
218 | } | |
219 | ||
220 | /* | |
221 | * The following block of code has to be executed atomically | |
222 | */ | |
06fcb0c6 | 223 | spin_lock_irqsave(&desc->lock, flags); |
1da177e4 | 224 | p = &desc->action; |
06fcb0c6 IM |
225 | old = *p; |
226 | if (old) { | |
e76de9f8 TG |
227 | /* |
228 | * Can't share interrupts unless both agree to and are | |
229 | * the same type (level, edge, polarity). So both flag | |
3cca53b0 | 230 | * fields must have IRQF_SHARED set and the bits which |
e76de9f8 TG |
231 | * set the trigger type must match. |
232 | */ | |
3cca53b0 TG |
233 | if (!((old->flags & new->flags) & IRQF_SHARED) || |
234 | ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) | |
f5163427 DS |
235 | goto mismatch; |
236 | ||
3cca53b0 | 237 | #if defined(CONFIG_IRQ_PER_CPU) && defined(IRQF_PERCPU) |
f5163427 | 238 | /* All handlers must agree on per-cpuness */ |
3cca53b0 TG |
239 | if ((old->flags & IRQF_PERCPU) != |
240 | (new->flags & IRQF_PERCPU)) | |
f5163427 DS |
241 | goto mismatch; |
242 | #endif | |
1da177e4 LT |
243 | |
244 | /* add new interrupt at end of irq queue */ | |
245 | do { | |
246 | p = &old->next; | |
247 | old = *p; | |
248 | } while (old); | |
249 | shared = 1; | |
250 | } | |
251 | ||
252 | *p = new; | |
3cca53b0 TG |
253 | #if defined(CONFIG_IRQ_PER_CPU) && defined(IRQF_PERCPU) |
254 | if (new->flags & IRQF_PERCPU) | |
f5163427 DS |
255 | desc->status |= IRQ_PER_CPU; |
256 | #endif | |
1da177e4 | 257 | if (!shared) { |
6a6de9ef | 258 | irq_chip_set_defaults(desc->chip); |
e76de9f8 TG |
259 | |
260 | /* Setup the type (level, edge polarity) if configured: */ | |
3cca53b0 | 261 | if (new->flags & IRQF_TRIGGER_MASK) { |
e76de9f8 TG |
262 | if (desc->chip && desc->chip->set_type) |
263 | desc->chip->set_type(irq, | |
3cca53b0 | 264 | new->flags & IRQF_TRIGGER_MASK); |
e76de9f8 TG |
265 | else |
266 | /* | |
3cca53b0 | 267 | * IRQF_TRIGGER_* but the PIC does not support |
e76de9f8 TG |
268 | * multiple flow-types? |
269 | */ | |
3cca53b0 | 270 | printk(KERN_WARNING "No IRQF_TRIGGER set_type " |
e8c4b9d0 BH |
271 | "function for IRQ %d (%s)\n", irq, |
272 | desc->chip ? desc->chip->name : | |
273 | "unknown"); | |
e76de9f8 TG |
274 | } else |
275 | compat_irq_chip_set_default_handler(desc); | |
6a6de9ef | 276 | |
94d39e1f TG |
277 | desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING | |
278 | IRQ_INPROGRESS); | |
279 | ||
280 | if (!(desc->status & IRQ_NOAUTOEN)) { | |
281 | desc->depth = 0; | |
282 | desc->status &= ~IRQ_DISABLED; | |
283 | if (desc->chip->startup) | |
284 | desc->chip->startup(irq); | |
285 | else | |
286 | desc->chip->enable(irq); | |
e76de9f8 TG |
287 | } else |
288 | /* Undo nested disables: */ | |
289 | desc->depth = 1; | |
1da177e4 | 290 | } |
06fcb0c6 | 291 | spin_unlock_irqrestore(&desc->lock, flags); |
1da177e4 LT |
292 | |
293 | new->irq = irq; | |
294 | register_irq_proc(irq); | |
295 | new->dir = NULL; | |
296 | register_handler_proc(irq, new); | |
297 | ||
298 | return 0; | |
f5163427 DS |
299 | |
300 | mismatch: | |
301 | spin_unlock_irqrestore(&desc->lock, flags); | |
3cca53b0 | 302 | if (!(new->flags & IRQF_PROBE_SHARED)) { |
e8c4b9d0 | 303 | printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq); |
13e87ec6 AM |
304 | dump_stack(); |
305 | } | |
f5163427 | 306 | return -EBUSY; |
1da177e4 LT |
307 | } |
308 | ||
309 | /** | |
310 | * free_irq - free an interrupt | |
311 | * @irq: Interrupt line to free | |
312 | * @dev_id: Device identity to free | |
313 | * | |
314 | * Remove an interrupt handler. The handler is removed and if the | |
315 | * interrupt line is no longer in use by any driver it is disabled. | |
316 | * On a shared IRQ the caller must ensure the interrupt is disabled | |
317 | * on the card it drives before calling this function. The function | |
318 | * does not return until any executing interrupts for this IRQ | |
319 | * have completed. | |
320 | * | |
321 | * This function must not be called from interrupt context. | |
322 | */ | |
323 | void free_irq(unsigned int irq, void *dev_id) | |
324 | { | |
325 | struct irq_desc *desc; | |
326 | struct irqaction **p; | |
327 | unsigned long flags; | |
328 | ||
cd7b24bb | 329 | WARN_ON(in_interrupt()); |
1da177e4 LT |
330 | if (irq >= NR_IRQS) |
331 | return; | |
332 | ||
333 | desc = irq_desc + irq; | |
06fcb0c6 | 334 | spin_lock_irqsave(&desc->lock, flags); |
1da177e4 LT |
335 | p = &desc->action; |
336 | for (;;) { | |
06fcb0c6 | 337 | struct irqaction *action = *p; |
1da177e4 LT |
338 | |
339 | if (action) { | |
340 | struct irqaction **pp = p; | |
341 | ||
342 | p = &action->next; | |
343 | if (action->dev_id != dev_id) | |
344 | continue; | |
345 | ||
346 | /* Found it - now remove it from the list of entries */ | |
347 | *pp = action->next; | |
dbce706e | 348 | |
b77d6adc PBG |
349 | /* Currently used only by UML, might disappear one day.*/ |
350 | #ifdef CONFIG_IRQ_RELEASE_METHOD | |
d1bef4ed IM |
351 | if (desc->chip->release) |
352 | desc->chip->release(irq, dev_id); | |
b77d6adc | 353 | #endif |
dbce706e | 354 | |
1da177e4 LT |
355 | if (!desc->action) { |
356 | desc->status |= IRQ_DISABLED; | |
d1bef4ed IM |
357 | if (desc->chip->shutdown) |
358 | desc->chip->shutdown(irq); | |
1da177e4 | 359 | else |
d1bef4ed | 360 | desc->chip->disable(irq); |
1da177e4 | 361 | } |
06fcb0c6 | 362 | spin_unlock_irqrestore(&desc->lock, flags); |
1da177e4 LT |
363 | unregister_handler_proc(irq, action); |
364 | ||
365 | /* Make sure it's not being used on another CPU */ | |
366 | synchronize_irq(irq); | |
367 | kfree(action); | |
368 | return; | |
369 | } | |
e8c4b9d0 | 370 | printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq); |
06fcb0c6 | 371 | spin_unlock_irqrestore(&desc->lock, flags); |
1da177e4 LT |
372 | return; |
373 | } | |
374 | } | |
1da177e4 LT |
375 | EXPORT_SYMBOL(free_irq); |
376 | ||
377 | /** | |
378 | * request_irq - allocate an interrupt line | |
379 | * @irq: Interrupt line to allocate | |
380 | * @handler: Function to be called when the IRQ occurs | |
381 | * @irqflags: Interrupt type flags | |
382 | * @devname: An ascii name for the claiming device | |
383 | * @dev_id: A cookie passed back to the handler function | |
384 | * | |
385 | * This call allocates interrupt resources and enables the | |
386 | * interrupt line and IRQ handling. From the point this | |
387 | * call is made your handler function may be invoked. Since | |
388 | * your handler function must clear any interrupt the board | |
389 | * raises, you must take care both to initialise your hardware | |
390 | * and to set up the interrupt handler in the right order. | |
391 | * | |
392 | * Dev_id must be globally unique. Normally the address of the | |
393 | * device data structure is used as the cookie. Since the handler | |
394 | * receives this value it makes sense to use it. | |
395 | * | |
396 | * If your interrupt is shared you must pass a non NULL dev_id | |
397 | * as this is required when freeing the interrupt. | |
398 | * | |
399 | * Flags: | |
400 | * | |
3cca53b0 TG |
401 | * IRQF_SHARED Interrupt is shared |
402 | * IRQF_DISABLED Disable local interrupts while processing | |
403 | * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy | |
1da177e4 LT |
404 | * |
405 | */ | |
406 | int request_irq(unsigned int irq, | |
407 | irqreturn_t (*handler)(int, void *, struct pt_regs *), | |
06fcb0c6 | 408 | unsigned long irqflags, const char *devname, void *dev_id) |
1da177e4 | 409 | { |
06fcb0c6 | 410 | struct irqaction *action; |
1da177e4 LT |
411 | int retval; |
412 | ||
413 | /* | |
414 | * Sanity-check: shared interrupts must pass in a real dev-ID, | |
415 | * otherwise we'll have trouble later trying to figure out | |
416 | * which interrupt is which (messes up the interrupt freeing | |
417 | * logic etc). | |
418 | */ | |
3cca53b0 | 419 | if ((irqflags & IRQF_SHARED) && !dev_id) |
1da177e4 LT |
420 | return -EINVAL; |
421 | if (irq >= NR_IRQS) | |
422 | return -EINVAL; | |
6550c775 TG |
423 | if (irq_desc[irq].status & IRQ_NOREQUEST) |
424 | return -EINVAL; | |
1da177e4 LT |
425 | if (!handler) |
426 | return -EINVAL; | |
427 | ||
428 | action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC); | |
429 | if (!action) | |
430 | return -ENOMEM; | |
431 | ||
432 | action->handler = handler; | |
433 | action->flags = irqflags; | |
434 | cpus_clear(action->mask); | |
435 | action->name = devname; | |
436 | action->next = NULL; | |
437 | action->dev_id = dev_id; | |
438 | ||
eee45269 IK |
439 | select_smp_affinity(irq); |
440 | ||
1da177e4 LT |
441 | retval = setup_irq(irq, action); |
442 | if (retval) | |
443 | kfree(action); | |
444 | ||
445 | return retval; | |
446 | } | |
1da177e4 LT |
447 | EXPORT_SYMBOL(request_irq); |
448 |