Merge commit 'v2.6.27-rc8' into genirq
[kernel.git] / kernel / irq / chip.c
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                 WARN(1, KERN_ERR "Trying to initialize invalid IRQ%d\n", irq);
32                 return;
33         }
34
35         /* Ensure we don't have left over values from a previous use of this irq */
36         desc = irq_desc + irq;
37         spin_lock_irqsave(&desc->lock, flags);
38         desc->status = IRQ_DISABLED;
39         desc->chip = &no_irq_chip;
40         desc->handle_irq = handle_bad_irq;
41         desc->depth = 1;
42         desc->msi_desc = NULL;
43         desc->handler_data = NULL;
44         desc->chip_data = NULL;
45         desc->action = NULL;
46         desc->irq_count = 0;
47         desc->irqs_unhandled = 0;
48 #ifdef CONFIG_SMP
49         cpus_setall(desc->affinity);
50 #endif
51         spin_unlock_irqrestore(&desc->lock, flags);
52 }
53
54 /**
55  *      dynamic_irq_cleanup - cleanup a dynamically allocated irq
56  *      @irq:   irq number to initialize
57  */
58 void dynamic_irq_cleanup(unsigned int irq)
59 {
60         struct irq_desc *desc;
61         unsigned long flags;
62
63         if (irq >= NR_IRQS) {
64                 WARN(1, KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
65                 return;
66         }
67
68         desc = irq_desc + irq;
69         spin_lock_irqsave(&desc->lock, flags);
70         if (desc->action) {
71                 spin_unlock_irqrestore(&desc->lock, flags);
72                 WARN(1, KERN_ERR "Destroying IRQ%d without calling free_irq\n",
73                         irq);
74                 return;
75         }
76         desc->msi_desc = NULL;
77         desc->handler_data = NULL;
78         desc->chip_data = NULL;
79         desc->handle_irq = handle_bad_irq;
80         desc->chip = &no_irq_chip;
81         spin_unlock_irqrestore(&desc->lock, flags);
82 }
83
84
85 /**
86  *      set_irq_chip - set the irq chip for an irq
87  *      @irq:   irq number
88  *      @chip:  pointer to irq chip description structure
89  */
90 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
91 {
92         struct irq_desc *desc;
93         unsigned long flags;
94
95         if (irq >= NR_IRQS) {
96                 WARN(1, KERN_ERR "Trying to install chip for IRQ%d\n", irq);
97                 return -EINVAL;
98         }
99
100         if (!chip)
101                 chip = &no_irq_chip;
102
103         desc = irq_desc + irq;
104         spin_lock_irqsave(&desc->lock, flags);
105         irq_chip_set_defaults(chip);
106         desc->chip = chip;
107         spin_unlock_irqrestore(&desc->lock, flags);
108
109         return 0;
110 }
111 EXPORT_SYMBOL(set_irq_chip);
112
113 /**
114  *      set_irq_type - set the irq type for an irq
115  *      @irq:   irq number
116  *      @type:  interrupt type - see include/linux/interrupt.h
117  */
118 int set_irq_type(unsigned int irq, unsigned int type)
119 {
120         struct irq_desc *desc;
121         unsigned long flags;
122         int ret = -ENXIO;
123
124         if (irq >= NR_IRQS) {
125                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
126                 return -ENODEV;
127         }
128
129         desc = irq_desc + irq;
130         if (desc->chip->set_type) {
131                 spin_lock_irqsave(&desc->lock, flags);
132                 ret = desc->chip->set_type(irq, type);
133                 spin_unlock_irqrestore(&desc->lock, flags);
134         }
135         return ret;
136 }
137 EXPORT_SYMBOL(set_irq_type);
138
139 /**
140  *      set_irq_data - set irq type data for an irq
141  *      @irq:   Interrupt number
142  *      @data:  Pointer to interrupt specific data
143  *
144  *      Set the hardware irq controller data for an irq
145  */
146 int set_irq_data(unsigned int irq, void *data)
147 {
148         struct irq_desc *desc;
149         unsigned long flags;
150
151         if (irq >= NR_IRQS) {
152                 printk(KERN_ERR
153                        "Trying to install controller data for IRQ%d\n", irq);
154                 return -EINVAL;
155         }
156
157         desc = irq_desc + irq;
158         spin_lock_irqsave(&desc->lock, flags);
159         desc->handler_data = data;
160         spin_unlock_irqrestore(&desc->lock, flags);
161         return 0;
162 }
163 EXPORT_SYMBOL(set_irq_data);
164
165 /**
166  *      set_irq_data - set irq type data for an irq
167  *      @irq:   Interrupt number
168  *      @entry: Pointer to MSI descriptor data
169  *
170  *      Set the hardware irq controller data for an irq
171  */
172 int set_irq_msi(unsigned int irq, struct msi_desc *entry)
173 {
174         struct irq_desc *desc;
175         unsigned long flags;
176
177         if (irq >= NR_IRQS) {
178                 printk(KERN_ERR
179                        "Trying to install msi data for IRQ%d\n", irq);
180                 return -EINVAL;
181         }
182         desc = irq_desc + irq;
183         spin_lock_irqsave(&desc->lock, flags);
184         desc->msi_desc = entry;
185         if (entry)
186                 entry->irq = irq;
187         spin_unlock_irqrestore(&desc->lock, flags);
188         return 0;
189 }
190
191 /**
192  *      set_irq_chip_data - set irq chip data for an irq
193  *      @irq:   Interrupt number
194  *      @data:  Pointer to chip specific data
195  *
196  *      Set the hardware irq chip data for an irq
197  */
198 int set_irq_chip_data(unsigned int irq, void *data)
199 {
200         struct irq_desc *desc = irq_desc + irq;
201         unsigned long flags;
202
203         if (irq >= NR_IRQS || !desc->chip) {
204                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
205                 return -EINVAL;
206         }
207
208         spin_lock_irqsave(&desc->lock, flags);
209         desc->chip_data = data;
210         spin_unlock_irqrestore(&desc->lock, flags);
211
212         return 0;
213 }
214 EXPORT_SYMBOL(set_irq_chip_data);
215
216 /*
217  * default enable function
218  */
219 static void default_enable(unsigned int irq)
220 {
221         struct irq_desc *desc = irq_desc + irq;
222
223         desc->chip->unmask(irq);
224         desc->status &= ~IRQ_MASKED;
225 }
226
227 /*
228  * default disable function
229  */
230 static void default_disable(unsigned int irq)
231 {
232 }
233
234 /*
235  * default startup function
236  */
237 static unsigned int default_startup(unsigned int irq)
238 {
239         irq_desc[irq].chip->enable(irq);
240
241         return 0;
242 }
243
244 /*
245  * default shutdown function
246  */
247 static void default_shutdown(unsigned int irq)
248 {
249         struct irq_desc *desc = irq_desc + irq;
250
251         desc->chip->mask(irq);
252         desc->status |= IRQ_MASKED;
253 }
254
255 /*
256  * Fixup enable/disable function pointers
257  */
258 void irq_chip_set_defaults(struct irq_chip *chip)
259 {
260         if (!chip->enable)
261                 chip->enable = default_enable;
262         if (!chip->disable)
263                 chip->disable = default_disable;
264         if (!chip->startup)
265                 chip->startup = default_startup;
266         /*
267          * We use chip->disable, when the user provided its own. When
268          * we have default_disable set for chip->disable, then we need
269          * to use default_shutdown, otherwise the irq line is not
270          * disabled on free_irq():
271          */
272         if (!chip->shutdown)
273                 chip->shutdown = chip->disable != default_disable ?
274                         chip->disable : default_shutdown;
275         if (!chip->name)
276                 chip->name = chip->typename;
277         if (!chip->end)
278                 chip->end = dummy_irq_chip.end;
279 }
280
281 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
282 {
283         if (desc->chip->mask_ack)
284                 desc->chip->mask_ack(irq);
285         else {
286                 desc->chip->mask(irq);
287                 desc->chip->ack(irq);
288         }
289 }
290
291 /**
292  *      handle_simple_irq - Simple and software-decoded IRQs.
293  *      @irq:   the interrupt number
294  *      @desc:  the interrupt description structure for this irq
295  *
296  *      Simple interrupts are either sent from a demultiplexing interrupt
297  *      handler or come from hardware, where no interrupt hardware control
298  *      is necessary.
299  *
300  *      Note: The caller is expected to handle the ack, clear, mask and
301  *      unmask issues if necessary.
302  */
303 void
304 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
305 {
306         struct irqaction *action;
307         irqreturn_t action_ret;
308         const unsigned int cpu = smp_processor_id();
309
310         spin_lock(&desc->lock);
311
312         if (unlikely(desc->status & IRQ_INPROGRESS))
313                 goto out_unlock;
314         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
315         kstat_cpu(cpu).irqs[irq]++;
316
317         action = desc->action;
318         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
319                 goto out_unlock;
320
321         desc->status |= IRQ_INPROGRESS;
322         spin_unlock(&desc->lock);
323
324         action_ret = handle_IRQ_event(irq, action);
325         if (!noirqdebug)
326                 note_interrupt(irq, desc, action_ret);
327
328         spin_lock(&desc->lock);
329         desc->status &= ~IRQ_INPROGRESS;
330 out_unlock:
331         spin_unlock(&desc->lock);
332 }
333
334 /**
335  *      handle_level_irq - Level type irq handler
336  *      @irq:   the interrupt number
337  *      @desc:  the interrupt description structure for this irq
338  *
339  *      Level type interrupts are active as long as the hardware line has
340  *      the active level. This may require to mask the interrupt and unmask
341  *      it after the associated handler has acknowledged the device, so the
342  *      interrupt line is back to inactive.
343  */
344 void
345 handle_level_irq(unsigned int irq, struct irq_desc *desc)
346 {
347         unsigned int cpu = smp_processor_id();
348         struct irqaction *action;
349         irqreturn_t action_ret;
350
351         spin_lock(&desc->lock);
352         mask_ack_irq(desc, irq);
353
354         if (unlikely(desc->status & IRQ_INPROGRESS))
355                 goto out_unlock;
356         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
357         kstat_cpu(cpu).irqs[irq]++;
358
359         /*
360          * If its disabled or no action available
361          * keep it masked and get out of here
362          */
363         action = desc->action;
364         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
365                 goto out_unlock;
366
367         desc->status |= IRQ_INPROGRESS;
368         spin_unlock(&desc->lock);
369
370         action_ret = handle_IRQ_event(irq, action);
371         if (!noirqdebug)
372                 note_interrupt(irq, desc, action_ret);
373
374         spin_lock(&desc->lock);
375         desc->status &= ~IRQ_INPROGRESS;
376         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
377                 desc->chip->unmask(irq);
378 out_unlock:
379         spin_unlock(&desc->lock);
380 }
381
382 /**
383  *      handle_fasteoi_irq - irq handler for transparent controllers
384  *      @irq:   the interrupt number
385  *      @desc:  the interrupt description structure for this irq
386  *
387  *      Only a single callback will be issued to the chip: an ->eoi()
388  *      call when the interrupt has been serviced. This enables support
389  *      for modern forms of interrupt handlers, which handle the flow
390  *      details in hardware, transparently.
391  */
392 void
393 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
394 {
395         unsigned int cpu = smp_processor_id();
396         struct irqaction *action;
397         irqreturn_t action_ret;
398
399         spin_lock(&desc->lock);
400
401         if (unlikely(desc->status & IRQ_INPROGRESS))
402                 goto out;
403
404         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
405         kstat_cpu(cpu).irqs[irq]++;
406
407         /*
408          * If its disabled or no action available
409          * then mask it and get out of here:
410          */
411         action = desc->action;
412         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
413                 desc->status |= IRQ_PENDING;
414                 if (desc->chip->mask)
415                         desc->chip->mask(irq);
416                 goto out;
417         }
418
419         desc->status |= IRQ_INPROGRESS;
420         desc->status &= ~IRQ_PENDING;
421         spin_unlock(&desc->lock);
422
423         action_ret = handle_IRQ_event(irq, action);
424         if (!noirqdebug)
425                 note_interrupt(irq, desc, action_ret);
426
427         spin_lock(&desc->lock);
428         desc->status &= ~IRQ_INPROGRESS;
429 out:
430         desc->chip->eoi(irq);
431
432         spin_unlock(&desc->lock);
433 }
434
435 /**
436  *      handle_edge_irq - edge type IRQ handler
437  *      @irq:   the interrupt number
438  *      @desc:  the interrupt description structure for this irq
439  *
440  *      Interrupt occures on the falling and/or rising edge of a hardware
441  *      signal. The occurence is latched into the irq controller hardware
442  *      and must be acked in order to be reenabled. After the ack another
443  *      interrupt can happen on the same source even before the first one
444  *      is handled by the assosiacted event handler. If this happens it
445  *      might be necessary to disable (mask) the interrupt depending on the
446  *      controller hardware. This requires to reenable the interrupt inside
447  *      of the loop which handles the interrupts which have arrived while
448  *      the handler was running. If all pending interrupts are handled, the
449  *      loop is left.
450  */
451 void
452 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
453 {
454         const unsigned int cpu = smp_processor_id();
455
456         spin_lock(&desc->lock);
457
458         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
459
460         /*
461          * If we're currently running this IRQ, or its disabled,
462          * we shouldn't process the IRQ. Mark it pending, handle
463          * the necessary masking and go out
464          */
465         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
466                     !desc->action)) {
467                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
468                 mask_ack_irq(desc, irq);
469                 goto out_unlock;
470         }
471
472         kstat_cpu(cpu).irqs[irq]++;
473
474         /* Start handling the irq */
475         desc->chip->ack(irq);
476
477         /* Mark the IRQ currently in progress.*/
478         desc->status |= IRQ_INPROGRESS;
479
480         do {
481                 struct irqaction *action = desc->action;
482                 irqreturn_t action_ret;
483
484                 if (unlikely(!action)) {
485                         desc->chip->mask(irq);
486                         goto out_unlock;
487                 }
488
489                 /*
490                  * When another irq arrived while we were handling
491                  * one, we could have masked the irq.
492                  * Renable it, if it was not disabled in meantime.
493                  */
494                 if (unlikely((desc->status &
495                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
496                               (IRQ_PENDING | IRQ_MASKED))) {
497                         desc->chip->unmask(irq);
498                         desc->status &= ~IRQ_MASKED;
499                 }
500
501                 desc->status &= ~IRQ_PENDING;
502                 spin_unlock(&desc->lock);
503                 action_ret = handle_IRQ_event(irq, action);
504                 if (!noirqdebug)
505                         note_interrupt(irq, desc, action_ret);
506                 spin_lock(&desc->lock);
507
508         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
509
510         desc->status &= ~IRQ_INPROGRESS;
511 out_unlock:
512         spin_unlock(&desc->lock);
513 }
514
515 /**
516  *      handle_percpu_IRQ - Per CPU local irq handler
517  *      @irq:   the interrupt number
518  *      @desc:  the interrupt description structure for this irq
519  *
520  *      Per CPU interrupts on SMP machines without locking requirements
521  */
522 void
523 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
524 {
525         irqreturn_t action_ret;
526
527         kstat_this_cpu.irqs[irq]++;
528
529         if (desc->chip->ack)
530                 desc->chip->ack(irq);
531
532         action_ret = handle_IRQ_event(irq, desc->action);
533         if (!noirqdebug)
534                 note_interrupt(irq, desc, action_ret);
535
536         if (desc->chip->eoi)
537                 desc->chip->eoi(irq);
538 }
539
540 void
541 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
542                   const char *name)
543 {
544         struct irq_desc *desc;
545         unsigned long flags;
546
547         if (irq >= NR_IRQS) {
548                 printk(KERN_ERR
549                        "Trying to install type control for IRQ%d\n", irq);
550                 return;
551         }
552
553         desc = irq_desc + irq;
554
555         if (!handle)
556                 handle = handle_bad_irq;
557         else if (desc->chip == &no_irq_chip) {
558                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
559                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
560                 /*
561                  * Some ARM implementations install a handler for really dumb
562                  * interrupt hardware without setting an irq_chip. This worked
563                  * with the ARM no_irq_chip but the check in setup_irq would
564                  * prevent us to setup the interrupt at all. Switch it to
565                  * dummy_irq_chip for easy transition.
566                  */
567                 desc->chip = &dummy_irq_chip;
568         }
569
570         spin_lock_irqsave(&desc->lock, flags);
571
572         /* Uninstall? */
573         if (handle == handle_bad_irq) {
574                 if (desc->chip != &no_irq_chip)
575                         mask_ack_irq(desc, irq);
576                 desc->status |= IRQ_DISABLED;
577                 desc->depth = 1;
578         }
579         desc->handle_irq = handle;
580         desc->name = name;
581
582         if (handle != handle_bad_irq && is_chained) {
583                 desc->status &= ~IRQ_DISABLED;
584                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
585                 desc->depth = 0;
586                 desc->chip->startup(irq);
587         }
588         spin_unlock_irqrestore(&desc->lock, flags);
589 }
590
591 void
592 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
593                          irq_flow_handler_t handle)
594 {
595         set_irq_chip(irq, chip);
596         __set_irq_handler(irq, handle, 0, NULL);
597 }
598
599 void
600 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
601                               irq_flow_handler_t handle, const char *name)
602 {
603         set_irq_chip(irq, chip);
604         __set_irq_handler(irq, handle, 0, name);
605 }
606
607 void __init set_irq_noprobe(unsigned int irq)
608 {
609         struct irq_desc *desc;
610         unsigned long flags;
611
612         if (irq >= NR_IRQS) {
613                 printk(KERN_ERR "Trying to mark IRQ%d non-probeable\n", irq);
614
615                 return;
616         }
617
618         desc = irq_desc + irq;
619
620         spin_lock_irqsave(&desc->lock, flags);
621         desc->status |= IRQ_NOPROBE;
622         spin_unlock_irqrestore(&desc->lock, flags);
623 }
624
625 void __init set_irq_probe(unsigned int irq)
626 {
627         struct irq_desc *desc;
628         unsigned long flags;
629
630         if (irq >= NR_IRQS) {
631                 printk(KERN_ERR "Trying to mark IRQ%d probeable\n", irq);
632
633                 return;
634         }
635
636         desc = irq_desc + irq;
637
638         spin_lock_irqsave(&desc->lock, flags);
639         desc->status &= ~IRQ_NOPROBE;
640         spin_unlock_irqrestore(&desc->lock, flags);
641 }