xref: /openbmc/linux/kernel/irq/chip.c (revision 22246614)
1 /*
2  * linux/kernel/irq/chip.c
3  *
4  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5  * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
6  *
7  * This file contains the core interrupt handling code, for irq-chip
8  * based architectures.
9  *
10  * Detailed information is available in Documentation/DocBook/genericirq
11  */
12 
13 #include <linux/irq.h>
14 #include <linux/msi.h>
15 #include <linux/module.h>
16 #include <linux/interrupt.h>
17 #include <linux/kernel_stat.h>
18 
19 #include "internals.h"
20 
21 /**
22  *	dynamic_irq_init - initialize a dynamically allocated irq
23  *	@irq:	irq number to initialize
24  */
25 void dynamic_irq_init(unsigned int irq)
26 {
27 	struct irq_desc *desc;
28 	unsigned long flags;
29 
30 	if (irq >= NR_IRQS) {
31 		printk(KERN_ERR "Trying to initialize invalid IRQ%d\n", irq);
32 		WARN_ON(1);
33 		return;
34 	}
35 
36 	/* Ensure we don't have left over values from a previous use of this irq */
37 	desc = irq_desc + irq;
38 	spin_lock_irqsave(&desc->lock, flags);
39 	desc->status = IRQ_DISABLED;
40 	desc->chip = &no_irq_chip;
41 	desc->handle_irq = handle_bad_irq;
42 	desc->depth = 1;
43 	desc->msi_desc = NULL;
44 	desc->handler_data = NULL;
45 	desc->chip_data = NULL;
46 	desc->action = NULL;
47 	desc->irq_count = 0;
48 	desc->irqs_unhandled = 0;
49 #ifdef CONFIG_SMP
50 	cpus_setall(desc->affinity);
51 #endif
52 	spin_unlock_irqrestore(&desc->lock, flags);
53 }
54 
55 /**
56  *	dynamic_irq_cleanup - cleanup a dynamically allocated irq
57  *	@irq:	irq number to initialize
58  */
59 void dynamic_irq_cleanup(unsigned int irq)
60 {
61 	struct irq_desc *desc;
62 	unsigned long flags;
63 
64 	if (irq >= NR_IRQS) {
65 		printk(KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
66 		WARN_ON(1);
67 		return;
68 	}
69 
70 	desc = irq_desc + irq;
71 	spin_lock_irqsave(&desc->lock, flags);
72 	if (desc->action) {
73 		spin_unlock_irqrestore(&desc->lock, flags);
74 		printk(KERN_ERR "Destroying IRQ%d without calling free_irq\n",
75 			irq);
76 		WARN_ON(1);
77 		return;
78 	}
79 	desc->msi_desc = NULL;
80 	desc->handler_data = NULL;
81 	desc->chip_data = NULL;
82 	desc->handle_irq = handle_bad_irq;
83 	desc->chip = &no_irq_chip;
84 	spin_unlock_irqrestore(&desc->lock, flags);
85 }
86 
87 
88 /**
89  *	set_irq_chip - set the irq chip for an irq
90  *	@irq:	irq number
91  *	@chip:	pointer to irq chip description structure
92  */
93 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
94 {
95 	struct irq_desc *desc;
96 	unsigned long flags;
97 
98 	if (irq >= NR_IRQS) {
99 		printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
100 		WARN_ON(1);
101 		return -EINVAL;
102 	}
103 
104 	if (!chip)
105 		chip = &no_irq_chip;
106 
107 	desc = irq_desc + irq;
108 	spin_lock_irqsave(&desc->lock, flags);
109 	irq_chip_set_defaults(chip);
110 	desc->chip = chip;
111 	spin_unlock_irqrestore(&desc->lock, flags);
112 
113 	return 0;
114 }
115 EXPORT_SYMBOL(set_irq_chip);
116 
117 /**
118  *	set_irq_type - set the irq type for an irq
119  *	@irq:	irq number
120  *	@type:	interrupt type - see include/linux/interrupt.h
121  */
122 int set_irq_type(unsigned int irq, unsigned int type)
123 {
124 	struct irq_desc *desc;
125 	unsigned long flags;
126 	int ret = -ENXIO;
127 
128 	if (irq >= NR_IRQS) {
129 		printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
130 		return -ENODEV;
131 	}
132 
133 	desc = irq_desc + irq;
134 	if (desc->chip->set_type) {
135 		spin_lock_irqsave(&desc->lock, flags);
136 		ret = desc->chip->set_type(irq, type);
137 		spin_unlock_irqrestore(&desc->lock, flags);
138 	}
139 	return ret;
140 }
141 EXPORT_SYMBOL(set_irq_type);
142 
143 /**
144  *	set_irq_data - set irq type data for an irq
145  *	@irq:	Interrupt number
146  *	@data:	Pointer to interrupt specific data
147  *
148  *	Set the hardware irq controller data for an irq
149  */
150 int set_irq_data(unsigned int irq, void *data)
151 {
152 	struct irq_desc *desc;
153 	unsigned long flags;
154 
155 	if (irq >= NR_IRQS) {
156 		printk(KERN_ERR
157 		       "Trying to install controller data for IRQ%d\n", irq);
158 		return -EINVAL;
159 	}
160 
161 	desc = irq_desc + irq;
162 	spin_lock_irqsave(&desc->lock, flags);
163 	desc->handler_data = data;
164 	spin_unlock_irqrestore(&desc->lock, flags);
165 	return 0;
166 }
167 EXPORT_SYMBOL(set_irq_data);
168 
169 /**
170  *	set_irq_data - set irq type data for an irq
171  *	@irq:	Interrupt number
172  *	@entry:	Pointer to MSI descriptor data
173  *
174  *	Set the hardware irq controller data for an irq
175  */
176 int set_irq_msi(unsigned int irq, struct msi_desc *entry)
177 {
178 	struct irq_desc *desc;
179 	unsigned long flags;
180 
181 	if (irq >= NR_IRQS) {
182 		printk(KERN_ERR
183 		       "Trying to install msi data for IRQ%d\n", irq);
184 		return -EINVAL;
185 	}
186 	desc = irq_desc + irq;
187 	spin_lock_irqsave(&desc->lock, flags);
188 	desc->msi_desc = entry;
189 	if (entry)
190 		entry->irq = irq;
191 	spin_unlock_irqrestore(&desc->lock, flags);
192 	return 0;
193 }
194 
195 /**
196  *	set_irq_chip_data - set irq chip data for an irq
197  *	@irq:	Interrupt number
198  *	@data:	Pointer to chip specific data
199  *
200  *	Set the hardware irq chip data for an irq
201  */
202 int set_irq_chip_data(unsigned int irq, void *data)
203 {
204 	struct irq_desc *desc = irq_desc + irq;
205 	unsigned long flags;
206 
207 	if (irq >= NR_IRQS || !desc->chip) {
208 		printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
209 		return -EINVAL;
210 	}
211 
212 	spin_lock_irqsave(&desc->lock, flags);
213 	desc->chip_data = data;
214 	spin_unlock_irqrestore(&desc->lock, flags);
215 
216 	return 0;
217 }
218 EXPORT_SYMBOL(set_irq_chip_data);
219 
220 /*
221  * default enable function
222  */
223 static void default_enable(unsigned int irq)
224 {
225 	struct irq_desc *desc = irq_desc + irq;
226 
227 	desc->chip->unmask(irq);
228 	desc->status &= ~IRQ_MASKED;
229 }
230 
231 /*
232  * default disable function
233  */
234 static void default_disable(unsigned int irq)
235 {
236 }
237 
238 /*
239  * default startup function
240  */
241 static unsigned int default_startup(unsigned int irq)
242 {
243 	irq_desc[irq].chip->enable(irq);
244 
245 	return 0;
246 }
247 
248 /*
249  * default shutdown function
250  */
251 static void default_shutdown(unsigned int irq)
252 {
253 	struct irq_desc *desc = irq_desc + irq;
254 
255 	desc->chip->mask(irq);
256 	desc->status |= IRQ_MASKED;
257 }
258 
259 /*
260  * Fixup enable/disable function pointers
261  */
262 void irq_chip_set_defaults(struct irq_chip *chip)
263 {
264 	if (!chip->enable)
265 		chip->enable = default_enable;
266 	if (!chip->disable)
267 		chip->disable = default_disable;
268 	if (!chip->startup)
269 		chip->startup = default_startup;
270 	/*
271 	 * We use chip->disable, when the user provided its own. When
272 	 * we have default_disable set for chip->disable, then we need
273 	 * to use default_shutdown, otherwise the irq line is not
274 	 * disabled on free_irq():
275 	 */
276 	if (!chip->shutdown)
277 		chip->shutdown = chip->disable != default_disable ?
278 			chip->disable : default_shutdown;
279 	if (!chip->name)
280 		chip->name = chip->typename;
281 	if (!chip->end)
282 		chip->end = dummy_irq_chip.end;
283 }
284 
285 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
286 {
287 	if (desc->chip->mask_ack)
288 		desc->chip->mask_ack(irq);
289 	else {
290 		desc->chip->mask(irq);
291 		desc->chip->ack(irq);
292 	}
293 }
294 
295 /**
296  *	handle_simple_irq - Simple and software-decoded IRQs.
297  *	@irq:	the interrupt number
298  *	@desc:	the interrupt description structure for this irq
299  *
300  *	Simple interrupts are either sent from a demultiplexing interrupt
301  *	handler or come from hardware, where no interrupt hardware control
302  *	is necessary.
303  *
304  *	Note: The caller is expected to handle the ack, clear, mask and
305  *	unmask issues if necessary.
306  */
307 void
308 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
309 {
310 	struct irqaction *action;
311 	irqreturn_t action_ret;
312 	const unsigned int cpu = smp_processor_id();
313 
314 	spin_lock(&desc->lock);
315 
316 	if (unlikely(desc->status & IRQ_INPROGRESS))
317 		goto out_unlock;
318 	desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
319 	kstat_cpu(cpu).irqs[irq]++;
320 
321 	action = desc->action;
322 	if (unlikely(!action || (desc->status & IRQ_DISABLED)))
323 		goto out_unlock;
324 
325 	desc->status |= IRQ_INPROGRESS;
326 	spin_unlock(&desc->lock);
327 
328 	action_ret = handle_IRQ_event(irq, action);
329 	if (!noirqdebug)
330 		note_interrupt(irq, desc, action_ret);
331 
332 	spin_lock(&desc->lock);
333 	desc->status &= ~IRQ_INPROGRESS;
334 out_unlock:
335 	spin_unlock(&desc->lock);
336 }
337 
338 /**
339  *	handle_level_irq - Level type irq handler
340  *	@irq:	the interrupt number
341  *	@desc:	the interrupt description structure for this irq
342  *
343  *	Level type interrupts are active as long as the hardware line has
344  *	the active level. This may require to mask the interrupt and unmask
345  *	it after the associated handler has acknowledged the device, so the
346  *	interrupt line is back to inactive.
347  */
348 void
349 handle_level_irq(unsigned int irq, struct irq_desc *desc)
350 {
351 	unsigned int cpu = smp_processor_id();
352 	struct irqaction *action;
353 	irqreturn_t action_ret;
354 
355 	spin_lock(&desc->lock);
356 	mask_ack_irq(desc, irq);
357 
358 	if (unlikely(desc->status & IRQ_INPROGRESS))
359 		goto out_unlock;
360 	desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
361 	kstat_cpu(cpu).irqs[irq]++;
362 
363 	/*
364 	 * If its disabled or no action available
365 	 * keep it masked and get out of here
366 	 */
367 	action = desc->action;
368 	if (unlikely(!action || (desc->status & IRQ_DISABLED)))
369 		goto out_unlock;
370 
371 	desc->status |= IRQ_INPROGRESS;
372 	spin_unlock(&desc->lock);
373 
374 	action_ret = handle_IRQ_event(irq, action);
375 	if (!noirqdebug)
376 		note_interrupt(irq, desc, action_ret);
377 
378 	spin_lock(&desc->lock);
379 	desc->status &= ~IRQ_INPROGRESS;
380 	if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
381 		desc->chip->unmask(irq);
382 out_unlock:
383 	spin_unlock(&desc->lock);
384 }
385 
386 /**
387  *	handle_fasteoi_irq - irq handler for transparent controllers
388  *	@irq:	the interrupt number
389  *	@desc:	the interrupt description structure for this irq
390  *
391  *	Only a single callback will be issued to the chip: an ->eoi()
392  *	call when the interrupt has been serviced. This enables support
393  *	for modern forms of interrupt handlers, which handle the flow
394  *	details in hardware, transparently.
395  */
396 void
397 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
398 {
399 	unsigned int cpu = smp_processor_id();
400 	struct irqaction *action;
401 	irqreturn_t action_ret;
402 
403 	spin_lock(&desc->lock);
404 
405 	if (unlikely(desc->status & IRQ_INPROGRESS))
406 		goto out;
407 
408 	desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
409 	kstat_cpu(cpu).irqs[irq]++;
410 
411 	/*
412 	 * If its disabled or no action available
413 	 * then mask it and get out of here:
414 	 */
415 	action = desc->action;
416 	if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
417 		desc->status |= IRQ_PENDING;
418 		if (desc->chip->mask)
419 			desc->chip->mask(irq);
420 		goto out;
421 	}
422 
423 	desc->status |= IRQ_INPROGRESS;
424 	desc->status &= ~IRQ_PENDING;
425 	spin_unlock(&desc->lock);
426 
427 	action_ret = handle_IRQ_event(irq, action);
428 	if (!noirqdebug)
429 		note_interrupt(irq, desc, action_ret);
430 
431 	spin_lock(&desc->lock);
432 	desc->status &= ~IRQ_INPROGRESS;
433 out:
434 	desc->chip->eoi(irq);
435 
436 	spin_unlock(&desc->lock);
437 }
438 
439 /**
440  *	handle_edge_irq - edge type IRQ handler
441  *	@irq:	the interrupt number
442  *	@desc:	the interrupt description structure for this irq
443  *
444  *	Interrupt occures on the falling and/or rising edge of a hardware
445  *	signal. The occurence is latched into the irq controller hardware
446  *	and must be acked in order to be reenabled. After the ack another
447  *	interrupt can happen on the same source even before the first one
448  *	is handled by the assosiacted event handler. If this happens it
449  *	might be necessary to disable (mask) the interrupt depending on the
450  *	controller hardware. This requires to reenable the interrupt inside
451  *	of the loop which handles the interrupts which have arrived while
452  *	the handler was running. If all pending interrupts are handled, the
453  *	loop is left.
454  */
455 void
456 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
457 {
458 	const unsigned int cpu = smp_processor_id();
459 
460 	spin_lock(&desc->lock);
461 
462 	desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
463 
464 	/*
465 	 * If we're currently running this IRQ, or its disabled,
466 	 * we shouldn't process the IRQ. Mark it pending, handle
467 	 * the necessary masking and go out
468 	 */
469 	if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
470 		    !desc->action)) {
471 		desc->status |= (IRQ_PENDING | IRQ_MASKED);
472 		mask_ack_irq(desc, irq);
473 		goto out_unlock;
474 	}
475 
476 	kstat_cpu(cpu).irqs[irq]++;
477 
478 	/* Start handling the irq */
479 	desc->chip->ack(irq);
480 
481 	/* Mark the IRQ currently in progress.*/
482 	desc->status |= IRQ_INPROGRESS;
483 
484 	do {
485 		struct irqaction *action = desc->action;
486 		irqreturn_t action_ret;
487 
488 		if (unlikely(!action)) {
489 			desc->chip->mask(irq);
490 			goto out_unlock;
491 		}
492 
493 		/*
494 		 * When another irq arrived while we were handling
495 		 * one, we could have masked the irq.
496 		 * Renable it, if it was not disabled in meantime.
497 		 */
498 		if (unlikely((desc->status &
499 			       (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
500 			      (IRQ_PENDING | IRQ_MASKED))) {
501 			desc->chip->unmask(irq);
502 			desc->status &= ~IRQ_MASKED;
503 		}
504 
505 		desc->status &= ~IRQ_PENDING;
506 		spin_unlock(&desc->lock);
507 		action_ret = handle_IRQ_event(irq, action);
508 		if (!noirqdebug)
509 			note_interrupt(irq, desc, action_ret);
510 		spin_lock(&desc->lock);
511 
512 	} while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
513 
514 	desc->status &= ~IRQ_INPROGRESS;
515 out_unlock:
516 	spin_unlock(&desc->lock);
517 }
518 
519 /**
520  *	handle_percpu_IRQ - Per CPU local irq handler
521  *	@irq:	the interrupt number
522  *	@desc:	the interrupt description structure for this irq
523  *
524  *	Per CPU interrupts on SMP machines without locking requirements
525  */
526 void
527 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
528 {
529 	irqreturn_t action_ret;
530 
531 	kstat_this_cpu.irqs[irq]++;
532 
533 	if (desc->chip->ack)
534 		desc->chip->ack(irq);
535 
536 	action_ret = handle_IRQ_event(irq, desc->action);
537 	if (!noirqdebug)
538 		note_interrupt(irq, desc, action_ret);
539 
540 	if (desc->chip->eoi)
541 		desc->chip->eoi(irq);
542 }
543 
544 void
545 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
546 		  const char *name)
547 {
548 	struct irq_desc *desc;
549 	unsigned long flags;
550 
551 	if (irq >= NR_IRQS) {
552 		printk(KERN_ERR
553 		       "Trying to install type control for IRQ%d\n", irq);
554 		return;
555 	}
556 
557 	desc = irq_desc + irq;
558 
559 	if (!handle)
560 		handle = handle_bad_irq;
561 	else if (desc->chip == &no_irq_chip) {
562 		printk(KERN_WARNING "Trying to install %sinterrupt handler "
563 		       "for IRQ%d\n", is_chained ? "chained " : "", irq);
564 		/*
565 		 * Some ARM implementations install a handler for really dumb
566 		 * interrupt hardware without setting an irq_chip. This worked
567 		 * with the ARM no_irq_chip but the check in setup_irq would
568 		 * prevent us to setup the interrupt at all. Switch it to
569 		 * dummy_irq_chip for easy transition.
570 		 */
571 		desc->chip = &dummy_irq_chip;
572 	}
573 
574 	spin_lock_irqsave(&desc->lock, flags);
575 
576 	/* Uninstall? */
577 	if (handle == handle_bad_irq) {
578 		if (desc->chip != &no_irq_chip)
579 			mask_ack_irq(desc, irq);
580 		desc->status |= IRQ_DISABLED;
581 		desc->depth = 1;
582 	}
583 	desc->handle_irq = handle;
584 	desc->name = name;
585 
586 	if (handle != handle_bad_irq && is_chained) {
587 		desc->status &= ~IRQ_DISABLED;
588 		desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
589 		desc->depth = 0;
590 		desc->chip->unmask(irq);
591 	}
592 	spin_unlock_irqrestore(&desc->lock, flags);
593 }
594 
595 void
596 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
597 			 irq_flow_handler_t handle)
598 {
599 	set_irq_chip(irq, chip);
600 	__set_irq_handler(irq, handle, 0, NULL);
601 }
602 
603 void
604 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
605 			      irq_flow_handler_t handle, const char *name)
606 {
607 	set_irq_chip(irq, chip);
608 	__set_irq_handler(irq, handle, 0, name);
609 }
610 
611 void __init set_irq_noprobe(unsigned int irq)
612 {
613 	struct irq_desc *desc;
614 	unsigned long flags;
615 
616 	if (irq >= NR_IRQS) {
617 		printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
618 
619 		return;
620 	}
621 
622 	desc = irq_desc + irq;
623 
624 	spin_lock_irqsave(&desc->lock, flags);
625 	desc->status |= IRQ_NOPROBE;
626 	spin_unlock_irqrestore(&desc->lock, flags);
627 }
628 
629 void __init set_irq_probe(unsigned int irq)
630 {
631 	struct irq_desc *desc;
632 	unsigned long flags;
633 
634 	if (irq >= NR_IRQS) {
635 		printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
636 
637 		return;
638 	}
639 
640 	desc = irq_desc + irq;
641 
642 	spin_lock_irqsave(&desc->lock, flags);
643 	desc->status &= ~IRQ_NOPROBE;
644 	spin_unlock_irqrestore(&desc->lock, flags);
645 }
646