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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 | * | |
15a647eb DB |
140 | * Enable/disable power management wakeup mode, which is |
141 | * disabled by default. Enables and disables must match, | |
142 | * just as they match for non-wakeup mode support. | |
143 | * | |
144 | * Wakeup mode lets this IRQ wake the system from sleep | |
145 | * states like "suspend to RAM". | |
ba9a2331 TG |
146 | */ |
147 | int set_irq_wake(unsigned int irq, unsigned int on) | |
148 | { | |
149 | struct irq_desc *desc = irq_desc + irq; | |
150 | unsigned long flags; | |
151 | int ret = -ENXIO; | |
15a647eb | 152 | int (*set_wake)(unsigned, unsigned) = desc->chip->set_wake; |
ba9a2331 | 153 | |
15a647eb DB |
154 | /* wakeup-capable irqs can be shared between drivers that |
155 | * don't need to have the same sleep mode behaviors. | |
156 | */ | |
ba9a2331 | 157 | spin_lock_irqsave(&desc->lock, flags); |
15a647eb DB |
158 | if (on) { |
159 | if (desc->wake_depth++ == 0) | |
160 | desc->status |= IRQ_WAKEUP; | |
161 | else | |
162 | set_wake = NULL; | |
163 | } else { | |
164 | if (desc->wake_depth == 0) { | |
165 | printk(KERN_WARNING "Unbalanced IRQ %d " | |
166 | "wake disable\n", irq); | |
167 | WARN_ON(1); | |
168 | } else if (--desc->wake_depth == 0) | |
169 | desc->status &= ~IRQ_WAKEUP; | |
170 | else | |
171 | set_wake = NULL; | |
172 | } | |
173 | if (set_wake) | |
ba9a2331 TG |
174 | ret = desc->chip->set_wake(irq, on); |
175 | spin_unlock_irqrestore(&desc->lock, flags); | |
176 | return ret; | |
177 | } | |
178 | EXPORT_SYMBOL(set_irq_wake); | |
179 | ||
1da177e4 LT |
180 | /* |
181 | * Internal function that tells the architecture code whether a | |
182 | * particular irq has been exclusively allocated or is available | |
183 | * for driver use. | |
184 | */ | |
185 | int can_request_irq(unsigned int irq, unsigned long irqflags) | |
186 | { | |
187 | struct irqaction *action; | |
188 | ||
6550c775 | 189 | if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST) |
1da177e4 LT |
190 | return 0; |
191 | ||
192 | action = irq_desc[irq].action; | |
193 | if (action) | |
3cca53b0 | 194 | if (irqflags & action->flags & IRQF_SHARED) |
1da177e4 LT |
195 | action = NULL; |
196 | ||
197 | return !action; | |
198 | } | |
199 | ||
6a6de9ef TG |
200 | void compat_irq_chip_set_default_handler(struct irq_desc *desc) |
201 | { | |
202 | /* | |
203 | * If the architecture still has not overriden | |
204 | * the flow handler then zap the default. This | |
205 | * should catch incorrect flow-type setting. | |
206 | */ | |
207 | if (desc->handle_irq == &handle_bad_irq) | |
208 | desc->handle_irq = NULL; | |
209 | } | |
210 | ||
1da177e4 LT |
211 | /* |
212 | * Internal function to register an irqaction - typically used to | |
213 | * allocate special interrupts that are part of the architecture. | |
214 | */ | |
06fcb0c6 | 215 | int setup_irq(unsigned int irq, struct irqaction *new) |
1da177e4 LT |
216 | { |
217 | struct irq_desc *desc = irq_desc + irq; | |
218 | struct irqaction *old, **p; | |
8b126b77 | 219 | const char *old_name = NULL; |
1da177e4 LT |
220 | unsigned long flags; |
221 | int shared = 0; | |
222 | ||
c2b5a251 MW |
223 | if (irq >= NR_IRQS) |
224 | return -EINVAL; | |
225 | ||
f1c2662c | 226 | if (desc->chip == &no_irq_chip) |
1da177e4 LT |
227 | return -ENOSYS; |
228 | /* | |
229 | * Some drivers like serial.c use request_irq() heavily, | |
230 | * so we have to be careful not to interfere with a | |
231 | * running system. | |
232 | */ | |
3cca53b0 | 233 | if (new->flags & IRQF_SAMPLE_RANDOM) { |
1da177e4 LT |
234 | /* |
235 | * This function might sleep, we want to call it first, | |
236 | * outside of the atomic block. | |
237 | * Yes, this might clear the entropy pool if the wrong | |
238 | * driver is attempted to be loaded, without actually | |
239 | * installing a new handler, but is this really a problem, | |
240 | * only the sysadmin is able to do this. | |
241 | */ | |
242 | rand_initialize_irq(irq); | |
243 | } | |
244 | ||
245 | /* | |
246 | * The following block of code has to be executed atomically | |
247 | */ | |
06fcb0c6 | 248 | spin_lock_irqsave(&desc->lock, flags); |
1da177e4 | 249 | p = &desc->action; |
06fcb0c6 IM |
250 | old = *p; |
251 | if (old) { | |
e76de9f8 TG |
252 | /* |
253 | * Can't share interrupts unless both agree to and are | |
254 | * the same type (level, edge, polarity). So both flag | |
3cca53b0 | 255 | * fields must have IRQF_SHARED set and the bits which |
e76de9f8 TG |
256 | * set the trigger type must match. |
257 | */ | |
3cca53b0 | 258 | if (!((old->flags & new->flags) & IRQF_SHARED) || |
8b126b77 AM |
259 | ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) { |
260 | old_name = old->name; | |
f5163427 | 261 | goto mismatch; |
8b126b77 | 262 | } |
f5163427 | 263 | |
284c6680 | 264 | #if defined(CONFIG_IRQ_PER_CPU) |
f5163427 | 265 | /* All handlers must agree on per-cpuness */ |
3cca53b0 TG |
266 | if ((old->flags & IRQF_PERCPU) != |
267 | (new->flags & IRQF_PERCPU)) | |
f5163427 DS |
268 | goto mismatch; |
269 | #endif | |
1da177e4 LT |
270 | |
271 | /* add new interrupt at end of irq queue */ | |
272 | do { | |
273 | p = &old->next; | |
274 | old = *p; | |
275 | } while (old); | |
276 | shared = 1; | |
277 | } | |
278 | ||
279 | *p = new; | |
284c6680 | 280 | #if defined(CONFIG_IRQ_PER_CPU) |
3cca53b0 | 281 | if (new->flags & IRQF_PERCPU) |
f5163427 DS |
282 | desc->status |= IRQ_PER_CPU; |
283 | #endif | |
950f4427 TG |
284 | /* Exclude IRQ from balancing */ |
285 | if (new->flags & IRQF_NOBALANCING) | |
286 | desc->status |= IRQ_NO_BALANCING; | |
287 | ||
1da177e4 | 288 | if (!shared) { |
6a6de9ef | 289 | irq_chip_set_defaults(desc->chip); |
e76de9f8 TG |
290 | |
291 | /* Setup the type (level, edge polarity) if configured: */ | |
3cca53b0 | 292 | if (new->flags & IRQF_TRIGGER_MASK) { |
e76de9f8 TG |
293 | if (desc->chip && desc->chip->set_type) |
294 | desc->chip->set_type(irq, | |
3cca53b0 | 295 | new->flags & IRQF_TRIGGER_MASK); |
e76de9f8 TG |
296 | else |
297 | /* | |
3cca53b0 | 298 | * IRQF_TRIGGER_* but the PIC does not support |
e76de9f8 TG |
299 | * multiple flow-types? |
300 | */ | |
3cca53b0 | 301 | printk(KERN_WARNING "No IRQF_TRIGGER set_type " |
e8c4b9d0 BH |
302 | "function for IRQ %d (%s)\n", irq, |
303 | desc->chip ? desc->chip->name : | |
304 | "unknown"); | |
e76de9f8 TG |
305 | } else |
306 | compat_irq_chip_set_default_handler(desc); | |
6a6de9ef | 307 | |
94d39e1f TG |
308 | desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING | |
309 | IRQ_INPROGRESS); | |
310 | ||
311 | if (!(desc->status & IRQ_NOAUTOEN)) { | |
312 | desc->depth = 0; | |
313 | desc->status &= ~IRQ_DISABLED; | |
314 | if (desc->chip->startup) | |
315 | desc->chip->startup(irq); | |
316 | else | |
317 | desc->chip->enable(irq); | |
e76de9f8 TG |
318 | } else |
319 | /* Undo nested disables: */ | |
320 | desc->depth = 1; | |
1da177e4 | 321 | } |
8528b0f1 LT |
322 | /* Reset broken irq detection when installing new handler */ |
323 | desc->irq_count = 0; | |
324 | desc->irqs_unhandled = 0; | |
06fcb0c6 | 325 | spin_unlock_irqrestore(&desc->lock, flags); |
1da177e4 LT |
326 | |
327 | new->irq = irq; | |
328 | register_irq_proc(irq); | |
329 | new->dir = NULL; | |
330 | register_handler_proc(irq, new); | |
331 | ||
332 | return 0; | |
f5163427 DS |
333 | |
334 | mismatch: | |
3f050447 | 335 | #ifdef CONFIG_DEBUG_SHIRQ |
3cca53b0 | 336 | if (!(new->flags & IRQF_PROBE_SHARED)) { |
e8c4b9d0 | 337 | printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq); |
8b126b77 AM |
338 | if (old_name) |
339 | printk(KERN_ERR "current handler: %s\n", old_name); | |
13e87ec6 AM |
340 | dump_stack(); |
341 | } | |
3f050447 | 342 | #endif |
8b126b77 | 343 | spin_unlock_irqrestore(&desc->lock, flags); |
f5163427 | 344 | return -EBUSY; |
1da177e4 LT |
345 | } |
346 | ||
347 | /** | |
348 | * free_irq - free an interrupt | |
349 | * @irq: Interrupt line to free | |
350 | * @dev_id: Device identity to free | |
351 | * | |
352 | * Remove an interrupt handler. The handler is removed and if the | |
353 | * interrupt line is no longer in use by any driver it is disabled. | |
354 | * On a shared IRQ the caller must ensure the interrupt is disabled | |
355 | * on the card it drives before calling this function. The function | |
356 | * does not return until any executing interrupts for this IRQ | |
357 | * have completed. | |
358 | * | |
359 | * This function must not be called from interrupt context. | |
360 | */ | |
361 | void free_irq(unsigned int irq, void *dev_id) | |
362 | { | |
363 | struct irq_desc *desc; | |
364 | struct irqaction **p; | |
365 | unsigned long flags; | |
a304e1b8 | 366 | irqreturn_t (*handler)(int, void *) = NULL; |
1da177e4 | 367 | |
cd7b24bb | 368 | WARN_ON(in_interrupt()); |
1da177e4 LT |
369 | if (irq >= NR_IRQS) |
370 | return; | |
371 | ||
372 | desc = irq_desc + irq; | |
06fcb0c6 | 373 | spin_lock_irqsave(&desc->lock, flags); |
1da177e4 LT |
374 | p = &desc->action; |
375 | for (;;) { | |
06fcb0c6 | 376 | struct irqaction *action = *p; |
1da177e4 LT |
377 | |
378 | if (action) { | |
379 | struct irqaction **pp = p; | |
380 | ||
381 | p = &action->next; | |
382 | if (action->dev_id != dev_id) | |
383 | continue; | |
384 | ||
385 | /* Found it - now remove it from the list of entries */ | |
386 | *pp = action->next; | |
dbce706e | 387 | |
b77d6adc PBG |
388 | /* Currently used only by UML, might disappear one day.*/ |
389 | #ifdef CONFIG_IRQ_RELEASE_METHOD | |
d1bef4ed IM |
390 | if (desc->chip->release) |
391 | desc->chip->release(irq, dev_id); | |
b77d6adc | 392 | #endif |
dbce706e | 393 | |
1da177e4 LT |
394 | if (!desc->action) { |
395 | desc->status |= IRQ_DISABLED; | |
d1bef4ed IM |
396 | if (desc->chip->shutdown) |
397 | desc->chip->shutdown(irq); | |
1da177e4 | 398 | else |
d1bef4ed | 399 | desc->chip->disable(irq); |
1da177e4 | 400 | } |
06fcb0c6 | 401 | spin_unlock_irqrestore(&desc->lock, flags); |
1da177e4 LT |
402 | unregister_handler_proc(irq, action); |
403 | ||
404 | /* Make sure it's not being used on another CPU */ | |
405 | synchronize_irq(irq); | |
a304e1b8 DW |
406 | if (action->flags & IRQF_SHARED) |
407 | handler = action->handler; | |
1da177e4 LT |
408 | kfree(action); |
409 | return; | |
410 | } | |
e8c4b9d0 | 411 | printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq); |
06fcb0c6 | 412 | spin_unlock_irqrestore(&desc->lock, flags); |
1da177e4 LT |
413 | return; |
414 | } | |
a304e1b8 DW |
415 | #ifdef CONFIG_DEBUG_SHIRQ |
416 | if (handler) { | |
417 | /* | |
418 | * It's a shared IRQ -- the driver ought to be prepared for it | |
419 | * to happen even now it's being freed, so let's make sure.... | |
420 | * We do this after actually deregistering it, to make sure that | |
421 | * a 'real' IRQ doesn't run in parallel with our fake | |
422 | */ | |
423 | handler(irq, dev_id); | |
424 | } | |
425 | #endif | |
1da177e4 | 426 | } |
1da177e4 LT |
427 | EXPORT_SYMBOL(free_irq); |
428 | ||
429 | /** | |
430 | * request_irq - allocate an interrupt line | |
431 | * @irq: Interrupt line to allocate | |
432 | * @handler: Function to be called when the IRQ occurs | |
433 | * @irqflags: Interrupt type flags | |
434 | * @devname: An ascii name for the claiming device | |
435 | * @dev_id: A cookie passed back to the handler function | |
436 | * | |
437 | * This call allocates interrupt resources and enables the | |
438 | * interrupt line and IRQ handling. From the point this | |
439 | * call is made your handler function may be invoked. Since | |
440 | * your handler function must clear any interrupt the board | |
441 | * raises, you must take care both to initialise your hardware | |
442 | * and to set up the interrupt handler in the right order. | |
443 | * | |
444 | * Dev_id must be globally unique. Normally the address of the | |
445 | * device data structure is used as the cookie. Since the handler | |
446 | * receives this value it makes sense to use it. | |
447 | * | |
448 | * If your interrupt is shared you must pass a non NULL dev_id | |
449 | * as this is required when freeing the interrupt. | |
450 | * | |
451 | * Flags: | |
452 | * | |
3cca53b0 TG |
453 | * IRQF_SHARED Interrupt is shared |
454 | * IRQF_DISABLED Disable local interrupts while processing | |
455 | * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy | |
1da177e4 LT |
456 | * |
457 | */ | |
da482792 | 458 | int request_irq(unsigned int irq, irq_handler_t handler, |
06fcb0c6 | 459 | unsigned long irqflags, const char *devname, void *dev_id) |
1da177e4 | 460 | { |
06fcb0c6 | 461 | struct irqaction *action; |
1da177e4 LT |
462 | int retval; |
463 | ||
fbb9ce95 IM |
464 | #ifdef CONFIG_LOCKDEP |
465 | /* | |
466 | * Lockdep wants atomic interrupt handlers: | |
467 | */ | |
38515e90 | 468 | irqflags |= IRQF_DISABLED; |
fbb9ce95 | 469 | #endif |
1da177e4 LT |
470 | /* |
471 | * Sanity-check: shared interrupts must pass in a real dev-ID, | |
472 | * otherwise we'll have trouble later trying to figure out | |
473 | * which interrupt is which (messes up the interrupt freeing | |
474 | * logic etc). | |
475 | */ | |
3cca53b0 | 476 | if ((irqflags & IRQF_SHARED) && !dev_id) |
1da177e4 LT |
477 | return -EINVAL; |
478 | if (irq >= NR_IRQS) | |
479 | return -EINVAL; | |
6550c775 TG |
480 | if (irq_desc[irq].status & IRQ_NOREQUEST) |
481 | return -EINVAL; | |
1da177e4 LT |
482 | if (!handler) |
483 | return -EINVAL; | |
484 | ||
485 | action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC); | |
486 | if (!action) | |
487 | return -ENOMEM; | |
488 | ||
489 | action->handler = handler; | |
490 | action->flags = irqflags; | |
491 | cpus_clear(action->mask); | |
492 | action->name = devname; | |
493 | action->next = NULL; | |
494 | action->dev_id = dev_id; | |
495 | ||
eee45269 IK |
496 | select_smp_affinity(irq); |
497 | ||
a304e1b8 DW |
498 | #ifdef CONFIG_DEBUG_SHIRQ |
499 | if (irqflags & IRQF_SHARED) { | |
500 | /* | |
501 | * It's a shared IRQ -- the driver ought to be prepared for it | |
502 | * to happen immediately, so let's make sure.... | |
503 | * We do this before actually registering it, to make sure that | |
504 | * a 'real' IRQ doesn't run in parallel with our fake | |
505 | */ | |
506 | if (irqflags & IRQF_DISABLED) { | |
507 | unsigned long flags; | |
508 | ||
509 | local_irq_save(flags); | |
510 | handler(irq, dev_id); | |
511 | local_irq_restore(flags); | |
512 | } else | |
513 | handler(irq, dev_id); | |
514 | } | |
515 | #endif | |
516 | ||
1da177e4 LT |
517 | retval = setup_irq(irq, action); |
518 | if (retval) | |
519 | kfree(action); | |
520 | ||
521 | return retval; | |
522 | } | |
1da177e4 | 523 | EXPORT_SYMBOL(request_irq); |