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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/kernel/irq/manage.c
3 *
Ingo Molnara34db9b2006-06-29 02:24:50 -07004 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5 * Copyright (C) 2005-2006 Thomas Gleixner
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 *
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070019/**
20 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
Randy Dunlap1e5d5332005-11-07 01:01:06 -080021 * @irq: interrupt number to wait for
Linus Torvalds1da177e2005-04-16 15:20:36 -070022 *
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 */
29void synchronize_irq(unsigned int irq)
30{
31 struct irq_desc *desc = irq_desc + irq;
32
Matthew Wilcoxc2b5a252005-11-03 07:51:18 -070033 if (irq >= NR_IRQS)
34 return;
35
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 while (desc->status & IRQ_INPROGRESS)
37 cpu_relax();
38}
Linus Torvalds1da177e2005-04-16 15:20:36 -070039EXPORT_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 */
54void disable_irq_nosync(unsigned int irq)
55{
Ingo Molnar34ffdb72006-06-29 02:24:40 -070056 struct irq_desc *desc = irq_desc + irq;
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 unsigned long flags;
58
Matthew Wilcoxc2b5a252005-11-03 07:51:18 -070059 if (irq >= NR_IRQS)
60 return;
61
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 spin_lock_irqsave(&desc->lock, flags);
63 if (!desc->depth++) {
64 desc->status |= IRQ_DISABLED;
Ingo Molnard1bef4e2006-06-29 02:24:36 -070065 desc->chip->disable(irq);
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 }
67 spin_unlock_irqrestore(&desc->lock, flags);
68}
Linus Torvalds1da177e2005-04-16 15:20:36 -070069EXPORT_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 */
83void disable_irq(unsigned int irq)
84{
Ingo Molnar34ffdb72006-06-29 02:24:40 -070085 struct irq_desc *desc = irq_desc + irq;
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
Matthew Wilcoxc2b5a252005-11-03 07:51:18 -070087 if (irq >= NR_IRQS)
88 return;
89
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 disable_irq_nosync(irq);
91 if (desc->action)
92 synchronize_irq(irq);
93}
Linus Torvalds1da177e2005-04-16 15:20:36 -070094EXPORT_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 */
106void enable_irq(unsigned int irq)
107{
Ingo Molnar34ffdb72006-06-29 02:24:40 -0700108 struct irq_desc *desc = irq_desc + irq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 unsigned long flags;
110
Matthew Wilcoxc2b5a252005-11-03 07:51:18 -0700111 if (irq >= NR_IRQS)
112 return;
113
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 spin_lock_irqsave(&desc->lock, flags);
115 switch (desc->depth) {
116 case 0:
Bjorn Helgaase8c4b9d2006-07-01 04:35:45 -0700117 printk(KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 WARN_ON(1);
119 break;
120 case 1: {
Thomas Gleixner3418d722006-06-29 02:24:49 -0700121 unsigned int status = desc->status & ~IRQ_DISABLED;
122
123 /* Prevent probing on this irq: */
124 desc->status = status | IRQ_NOPROBE;
Thomas Gleixnera4633adc2006-06-29 02:24:48 -0700125 check_irq_resend(desc, irq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 /* fall-through */
127 }
128 default:
129 desc->depth--;
130 }
131 spin_unlock_irqrestore(&desc->lock, flags);
132}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133EXPORT_SYMBOL(enable_irq);
134
Thomas Gleixnerba9a2332006-06-29 02:24:55 -0700135/**
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 */
142int 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}
154EXPORT_SYMBOL(set_irq_wake);
155
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156/*
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 */
161int can_request_irq(unsigned int irq, unsigned long irqflags)
162{
163 struct irqaction *action;
164
Thomas Gleixner6550c772006-06-29 02:24:49 -0700165 if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 return 0;
167
168 action = irq_desc[irq].action;
169 if (action)
170 if (irqflags & action->flags & SA_SHIRQ)
171 action = NULL;
172
173 return !action;
174}
175
Thomas Gleixner6a6de9e2006-06-29 02:24:51 -0700176void 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187/*
188 * Internal function to register an irqaction - typically used to
189 * allocate special interrupts that are part of the architecture.
190 */
Ingo Molnar06fcb0c2006-06-29 02:24:40 -0700191int setup_irq(unsigned int irq, struct irqaction *new)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192{
193 struct irq_desc *desc = irq_desc + irq;
194 struct irqaction *old, **p;
195 unsigned long flags;
196 int shared = 0;
197
Matthew Wilcoxc2b5a252005-11-03 07:51:18 -0700198 if (irq >= NR_IRQS)
199 return -EINVAL;
200
Ingo Molnarf1c26622006-06-29 02:24:57 -0700201 if (desc->chip == &no_irq_chip)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 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 */
208 if (new->flags & SA_SAMPLE_RANDOM) {
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 */
Ingo Molnar06fcb0c2006-06-29 02:24:40 -0700223 spin_lock_irqsave(&desc->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 p = &desc->action;
Ingo Molnar06fcb0c2006-06-29 02:24:40 -0700225 old = *p;
226 if (old) {
Thomas Gleixnere76de9f2006-06-29 02:24:56 -0700227 /*
228 * Can't share interrupts unless both agree to and are
229 * the same type (level, edge, polarity). So both flag
230 * fields must have SA_SHIRQ set and the bits which
231 * set the trigger type must match.
232 */
233 if (!((old->flags & new->flags) & SA_SHIRQ) ||
234 ((old->flags ^ new->flags) & SA_TRIGGER_MASK))
Dimitri Sivanichf5163422006-03-25 03:08:23 -0800235 goto mismatch;
236
Ingo Molnar0d7012a2006-06-29 02:24:43 -0700237#if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
Dimitri Sivanichf5163422006-03-25 03:08:23 -0800238 /* All handlers must agree on per-cpuness */
Bjorn Helgaas17311c02006-07-01 04:35:44 -0700239 if ((old->flags & SA_PERCPU_IRQ) !=
240 (new->flags & SA_PERCPU_IRQ))
Dimitri Sivanichf5163422006-03-25 03:08:23 -0800241 goto mismatch;
242#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243
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;
Ingo Molnar0d7012a2006-06-29 02:24:43 -0700253#if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
Dimitri Sivanichf5163422006-03-25 03:08:23 -0800254 if (new->flags & SA_PERCPU_IRQ)
255 desc->status |= IRQ_PER_CPU;
256#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 if (!shared) {
Thomas Gleixner6a6de9e2006-06-29 02:24:51 -0700258 irq_chip_set_defaults(desc->chip);
Thomas Gleixnere76de9f2006-06-29 02:24:56 -0700259
260 /* Setup the type (level, edge polarity) if configured: */
261 if (new->flags & SA_TRIGGER_MASK) {
262 if (desc->chip && desc->chip->set_type)
263 desc->chip->set_type(irq,
264 new->flags & SA_TRIGGER_MASK);
265 else
266 /*
267 * SA_TRIGGER_* but the PIC does not support
268 * multiple flow-types?
269 */
Bjorn Helgaase8c4b9d2006-07-01 04:35:45 -0700270 printk(KERN_WARNING "No SA_TRIGGER set_type "
271 "function for IRQ %d (%s)\n", irq,
272 desc->chip ? desc->chip->name :
273 "unknown");
Thomas Gleixnere76de9f2006-06-29 02:24:56 -0700274 } else
275 compat_irq_chip_set_default_handler(desc);
Thomas Gleixner6a6de9e2006-06-29 02:24:51 -0700276
Thomas Gleixner94d39e12006-06-29 02:24:50 -0700277 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);
Thomas Gleixnere76de9f2006-06-29 02:24:56 -0700287 } else
288 /* Undo nested disables: */
289 desc->depth = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 }
Ingo Molnar06fcb0c2006-06-29 02:24:40 -0700291 spin_unlock_irqrestore(&desc->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292
293 new->irq = irq;
294 register_irq_proc(irq);
295 new->dir = NULL;
296 register_handler_proc(irq, new);
297
298 return 0;
Dimitri Sivanichf5163422006-03-25 03:08:23 -0800299
300mismatch:
301 spin_unlock_irqrestore(&desc->lock, flags);
Andrew Morton13e87ec2006-04-27 18:39:18 -0700302 if (!(new->flags & SA_PROBEIRQ)) {
Bjorn Helgaase8c4b9d2006-07-01 04:35:45 -0700303 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
Andrew Morton13e87ec2006-04-27 18:39:18 -0700304 dump_stack();
305 }
Dimitri Sivanichf5163422006-03-25 03:08:23 -0800306 return -EBUSY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307}
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 */
323void free_irq(unsigned int irq, void *dev_id)
324{
325 struct irq_desc *desc;
326 struct irqaction **p;
327 unsigned long flags;
328
Ingo Molnarcd7b24b2006-03-26 01:36:54 -0800329 WARN_ON(in_interrupt());
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 if (irq >= NR_IRQS)
331 return;
332
333 desc = irq_desc + irq;
Ingo Molnar06fcb0c2006-06-29 02:24:40 -0700334 spin_lock_irqsave(&desc->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 p = &desc->action;
336 for (;;) {
Ingo Molnar06fcb0c2006-06-29 02:24:40 -0700337 struct irqaction *action = *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338
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;
Paolo 'Blaisorblade' Giarrussodbce7062005-06-21 17:16:19 -0700348
Paolo 'Blaisorblade' Giarrussob77d6ad2005-06-21 17:16:24 -0700349 /* Currently used only by UML, might disappear one day.*/
350#ifdef CONFIG_IRQ_RELEASE_METHOD
Ingo Molnard1bef4e2006-06-29 02:24:36 -0700351 if (desc->chip->release)
352 desc->chip->release(irq, dev_id);
Paolo 'Blaisorblade' Giarrussob77d6ad2005-06-21 17:16:24 -0700353#endif
Paolo 'Blaisorblade' Giarrussodbce7062005-06-21 17:16:19 -0700354
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 if (!desc->action) {
356 desc->status |= IRQ_DISABLED;
Ingo Molnard1bef4e2006-06-29 02:24:36 -0700357 if (desc->chip->shutdown)
358 desc->chip->shutdown(irq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 else
Ingo Molnard1bef4e2006-06-29 02:24:36 -0700360 desc->chip->disable(irq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 }
Ingo Molnar06fcb0c2006-06-29 02:24:40 -0700362 spin_unlock_irqrestore(&desc->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 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 }
Bjorn Helgaase8c4b9d2006-07-01 04:35:45 -0700370 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
Ingo Molnar06fcb0c2006-06-29 02:24:40 -0700371 spin_unlock_irqrestore(&desc->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 return;
373 }
374}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375EXPORT_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 *
401 * SA_SHIRQ Interrupt is shared
402 * SA_INTERRUPT Disable local interrupts while processing
403 * SA_SAMPLE_RANDOM The interrupt can be used for entropy
404 *
405 */
406int request_irq(unsigned int irq,
407 irqreturn_t (*handler)(int, void *, struct pt_regs *),
Ingo Molnar06fcb0c2006-06-29 02:24:40 -0700408 unsigned long irqflags, const char *devname, void *dev_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409{
Ingo Molnar06fcb0c2006-06-29 02:24:40 -0700410 struct irqaction *action;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 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 */
419 if ((irqflags & SA_SHIRQ) && !dev_id)
420 return -EINVAL;
421 if (irq >= NR_IRQS)
422 return -EINVAL;
Thomas Gleixner6550c772006-06-29 02:24:49 -0700423 if (irq_desc[irq].status & IRQ_NOREQUEST)
424 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 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
Ivan Kokshayskyeee45262006-01-06 00:12:21 -0800439 select_smp_affinity(irq);
440
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 retval = setup_irq(irq, action);
442 if (retval)
443 kfree(action);
444
445 return retval;
446}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447EXPORT_SYMBOL(request_irq);
448