genirq: fix devres.o build for GENERIC_HARDIRQS=n
[linux-2.6.git] / kernel / irq / handle.c
1 /*
2  * linux/kernel/irq/handle.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.
8  *
9  * Detailed information is available in Documentation/DocBook/genericirq
10  *
11  */
12
13 #include <linux/irq.h>
14 #include <linux/module.h>
15 #include <linux/random.h>
16 #include <linux/interrupt.h>
17 #include <linux/kernel_stat.h>
18 #include <linux/rculist.h>
19 #include <linux/hash.h>
20 #include <linux/bootmem.h>
21
22 #include "internals.h"
23
24 /*
25  * lockdep: we want to handle all irq_desc locks as a single lock-class:
26  */
27 struct lock_class_key irq_desc_lock_class;
28
29 /**
30  * handle_bad_irq - handle spurious and unhandled irqs
31  * @irq:       the interrupt number
32  * @desc:      description of the interrupt
33  *
34  * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
35  */
36 void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
37 {
38         print_irq_desc(irq, desc);
39         kstat_incr_irqs_this_cpu(irq, desc);
40         ack_bad_irq(irq);
41 }
42
43 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
44 static void __init init_irq_default_affinity(void)
45 {
46         alloc_bootmem_cpumask_var(&irq_default_affinity);
47         cpumask_setall(irq_default_affinity);
48 }
49 #else
50 static void __init init_irq_default_affinity(void)
51 {
52 }
53 #endif
54
55 /*
56  * Linux has a controller-independent interrupt architecture.
57  * Every controller has a 'controller-template', that is used
58  * by the main code to do the right thing. Each driver-visible
59  * interrupt source is transparently wired to the appropriate
60  * controller. Thus drivers need not be aware of the
61  * interrupt-controller.
62  *
63  * The code is designed to be easily extended with new/different
64  * interrupt controllers, without having to do assembly magic or
65  * having to touch the generic code.
66  *
67  * Controller mappings for all interrupt sources:
68  */
69 int nr_irqs = NR_IRQS;
70 EXPORT_SYMBOL_GPL(nr_irqs);
71
72 #ifdef CONFIG_SPARSE_IRQ
73
74 static struct irq_desc irq_desc_init = {
75         .irq        = -1,
76         .status     = IRQ_DISABLED,
77         .chip       = &no_irq_chip,
78         .handle_irq = handle_bad_irq,
79         .depth      = 1,
80         .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
81 };
82
83 void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
84 {
85         int node;
86         void *ptr;
87
88         node = cpu_to_node(cpu);
89         ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs), GFP_ATOMIC, node);
90
91         /*
92          * don't overwite if can not get new one
93          * init_copy_kstat_irqs() could still use old one
94          */
95         if (ptr) {
96                 printk(KERN_DEBUG "  alloc kstat_irqs on cpu %d node %d\n",
97                          cpu, node);
98                 desc->kstat_irqs = ptr;
99         }
100 }
101
102 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
103 {
104         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
105
106         spin_lock_init(&desc->lock);
107         desc->irq = irq;
108 #ifdef CONFIG_SMP
109         desc->cpu = cpu;
110 #endif
111         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
112         init_kstat_irqs(desc, cpu, nr_cpu_ids);
113         if (!desc->kstat_irqs) {
114                 printk(KERN_ERR "can not alloc kstat_irqs\n");
115                 BUG_ON(1);
116         }
117         if (!init_alloc_desc_masks(desc, cpu, false)) {
118                 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
119                 BUG_ON(1);
120         }
121         arch_init_chip_data(desc, cpu);
122 }
123
124 /*
125  * Protect the sparse_irqs:
126  */
127 DEFINE_SPINLOCK(sparse_irq_lock);
128
129 struct irq_desc **irq_desc_ptrs __read_mostly;
130
131 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
132         [0 ... NR_IRQS_LEGACY-1] = {
133                 .irq        = -1,
134                 .status     = IRQ_DISABLED,
135                 .chip       = &no_irq_chip,
136                 .handle_irq = handle_bad_irq,
137                 .depth      = 1,
138                 .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
139         }
140 };
141
142 static unsigned int *kstat_irqs_legacy;
143
144 int __init early_irq_init(void)
145 {
146         struct irq_desc *desc;
147         int legacy_count;
148         int i;
149
150         init_irq_default_affinity();
151
152          /* initialize nr_irqs based on nr_cpu_ids */
153         arch_probe_nr_irqs();
154         printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
155
156         desc = irq_desc_legacy;
157         legacy_count = ARRAY_SIZE(irq_desc_legacy);
158
159         /* allocate irq_desc_ptrs array based on nr_irqs */
160         irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));
161
162         /* allocate based on nr_cpu_ids */
163         /* FIXME: invert kstat_irgs, and it'd be a per_cpu_alloc'd thing */
164         kstat_irqs_legacy = alloc_bootmem(NR_IRQS_LEGACY * nr_cpu_ids *
165                                           sizeof(int));
166
167         for (i = 0; i < legacy_count; i++) {
168                 desc[i].irq = i;
169                 desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
170                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
171                 init_alloc_desc_masks(&desc[i], 0, true);
172                 irq_desc_ptrs[i] = desc + i;
173         }
174
175         for (i = legacy_count; i < nr_irqs; i++)
176                 irq_desc_ptrs[i] = NULL;
177
178         return arch_early_irq_init();
179 }
180
181 struct irq_desc *irq_to_desc(unsigned int irq)
182 {
183         if (irq_desc_ptrs && irq < nr_irqs)
184                 return irq_desc_ptrs[irq];
185
186         return NULL;
187 }
188
189 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
190 {
191         struct irq_desc *desc;
192         unsigned long flags;
193         int node;
194
195         if (irq >= nr_irqs) {
196                 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
197                         irq, nr_irqs);
198                 return NULL;
199         }
200
201         desc = irq_desc_ptrs[irq];
202         if (desc)
203                 return desc;
204
205         spin_lock_irqsave(&sparse_irq_lock, flags);
206
207         /* We have to check it to avoid races with another CPU */
208         desc = irq_desc_ptrs[irq];
209         if (desc)
210                 goto out_unlock;
211
212         node = cpu_to_node(cpu);
213         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
214         printk(KERN_DEBUG "  alloc irq_desc for %d on cpu %d node %d\n",
215                  irq, cpu, node);
216         if (!desc) {
217                 printk(KERN_ERR "can not alloc irq_desc\n");
218                 BUG_ON(1);
219         }
220         init_one_irq_desc(irq, desc, cpu);
221
222         irq_desc_ptrs[irq] = desc;
223
224 out_unlock:
225         spin_unlock_irqrestore(&sparse_irq_lock, flags);
226
227         return desc;
228 }
229
230 #else /* !CONFIG_SPARSE_IRQ */
231
232 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
233         [0 ... NR_IRQS-1] = {
234                 .status = IRQ_DISABLED,
235                 .chip = &no_irq_chip,
236                 .handle_irq = handle_bad_irq,
237                 .depth = 1,
238                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
239         }
240 };
241
242 static unsigned int kstat_irqs_all[NR_IRQS][NR_CPUS];
243 int __init early_irq_init(void)
244 {
245         struct irq_desc *desc;
246         int count;
247         int i;
248
249         init_irq_default_affinity();
250
251         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
252
253         desc = irq_desc;
254         count = ARRAY_SIZE(irq_desc);
255
256         for (i = 0; i < count; i++) {
257                 desc[i].irq = i;
258                 init_alloc_desc_masks(&desc[i], 0, true);
259                 desc[i].kstat_irqs = kstat_irqs_all[i];
260         }
261         return arch_early_irq_init();
262 }
263
264 struct irq_desc *irq_to_desc(unsigned int irq)
265 {
266         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
267 }
268
269 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
270 {
271         return irq_to_desc(irq);
272 }
273 #endif /* !CONFIG_SPARSE_IRQ */
274
275 void clear_kstat_irqs(struct irq_desc *desc)
276 {
277         memset(desc->kstat_irqs, 0, nr_cpu_ids * sizeof(*(desc->kstat_irqs)));
278 }
279
280 /*
281  * What should we do if we get a hw irq event on an illegal vector?
282  * Each architecture has to answer this themself.
283  */
284 static void ack_bad(unsigned int irq)
285 {
286         struct irq_desc *desc = irq_to_desc(irq);
287
288         print_irq_desc(irq, desc);
289         ack_bad_irq(irq);
290 }
291
292 /*
293  * NOP functions
294  */
295 static void noop(unsigned int irq)
296 {
297 }
298
299 static unsigned int noop_ret(unsigned int irq)
300 {
301         return 0;
302 }
303
304 /*
305  * Generic no controller implementation
306  */
307 struct irq_chip no_irq_chip = {
308         .name           = "none",
309         .startup        = noop_ret,
310         .shutdown       = noop,
311         .enable         = noop,
312         .disable        = noop,
313         .ack            = ack_bad,
314         .end            = noop,
315 };
316
317 /*
318  * Generic dummy implementation which can be used for
319  * real dumb interrupt sources
320  */
321 struct irq_chip dummy_irq_chip = {
322         .name           = "dummy",
323         .startup        = noop_ret,
324         .shutdown       = noop,
325         .enable         = noop,
326         .disable        = noop,
327         .ack            = noop,
328         .mask           = noop,
329         .unmask         = noop,
330         .end            = noop,
331 };
332
333 /*
334  * Special, empty irq handler:
335  */
336 irqreturn_t no_action(int cpl, void *dev_id)
337 {
338         return IRQ_NONE;
339 }
340
341 static void warn_no_thread(unsigned int irq, struct irqaction *action)
342 {
343         if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
344                 return;
345
346         printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
347                "but no thread function available.", irq, action->name);
348 }
349
350 /**
351  * handle_IRQ_event - irq action chain handler
352  * @irq:        the interrupt number
353  * @action:     the interrupt action chain for this irq
354  *
355  * Handles the action chain of an irq event
356  */
357 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
358 {
359         irqreturn_t ret, retval = IRQ_NONE;
360         unsigned int status = 0;
361
362         WARN_ONCE(!in_irq(), "BUG: IRQ handler called from non-hardirq context!");
363
364         if (!(action->flags & IRQF_DISABLED))
365                 local_irq_enable_in_hardirq();
366
367         do {
368                 ret = action->handler(irq, action->dev_id);
369
370                 switch (ret) {
371                 case IRQ_WAKE_THREAD:
372                         /*
373                          * Set result to handled so the spurious check
374                          * does not trigger.
375                          */
376                         ret = IRQ_HANDLED;
377
378                         /*
379                          * Catch drivers which return WAKE_THREAD but
380                          * did not set up a thread function
381                          */
382                         if (unlikely(!action->thread_fn)) {
383                                 warn_no_thread(irq, action);
384                                 break;
385                         }
386
387                         /*
388                          * Wake up the handler thread for this
389                          * action. In case the thread crashed and was
390                          * killed we just pretend that we handled the
391                          * interrupt. The hardirq handler above has
392                          * disabled the device interrupt, so no irq
393                          * storm is lurking.
394                          */
395                         if (likely(!test_bit(IRQTF_DIED,
396                                              &action->thread_flags))) {
397                                 set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
398                                 wake_up_process(action->thread);
399                         }
400
401                         /* Fall through to add to randomness */
402                 case IRQ_HANDLED:
403                         status |= action->flags;
404                         break;
405
406                 default:
407                         break;
408                 }
409
410                 retval |= ret;
411                 action = action->next;
412         } while (action);
413
414         if (status & IRQF_SAMPLE_RANDOM)
415                 add_interrupt_randomness(irq);
416         local_irq_disable();
417
418         return retval;
419 }
420
421 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
422
423 #ifdef CONFIG_ENABLE_WARN_DEPRECATED
424 # warning __do_IRQ is deprecated. Please convert to proper flow handlers
425 #endif
426
427 /**
428  * __do_IRQ - original all in one highlevel IRQ handler
429  * @irq:        the interrupt number
430  *
431  * __do_IRQ handles all normal device IRQ's (the special
432  * SMP cross-CPU interrupts have their own specific
433  * handlers).
434  *
435  * This is the original x86 implementation which is used for every
436  * interrupt type.
437  */
438 unsigned int __do_IRQ(unsigned int irq)
439 {
440         struct irq_desc *desc = irq_to_desc(irq);
441         struct irqaction *action;
442         unsigned int status;
443
444         kstat_incr_irqs_this_cpu(irq, desc);
445
446         if (CHECK_IRQ_PER_CPU(desc->status)) {
447                 irqreturn_t action_ret;
448
449                 /*
450                  * No locking required for CPU-local interrupts:
451                  */
452                 if (desc->chip->ack) {
453                         desc->chip->ack(irq);
454                         /* get new one */
455                         desc = irq_remap_to_desc(irq, desc);
456                 }
457                 if (likely(!(desc->status & IRQ_DISABLED))) {
458                         action_ret = handle_IRQ_event(irq, desc->action);
459                         if (!noirqdebug)
460                                 note_interrupt(irq, desc, action_ret);
461                 }
462                 desc->chip->end(irq);
463                 return 1;
464         }
465
466         spin_lock(&desc->lock);
467         if (desc->chip->ack) {
468                 desc->chip->ack(irq);
469                 desc = irq_remap_to_desc(irq, desc);
470         }
471         /*
472          * REPLAY is when Linux resends an IRQ that was dropped earlier
473          * WAITING is used by probe to mark irqs that are being tested
474          */
475         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
476         status |= IRQ_PENDING; /* we _want_ to handle it */
477
478         /*
479          * If the IRQ is disabled for whatever reason, we cannot
480          * use the action we have.
481          */
482         action = NULL;
483         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
484                 action = desc->action;
485                 status &= ~IRQ_PENDING; /* we commit to handling */
486                 status |= IRQ_INPROGRESS; /* we are handling it */
487         }
488         desc->status = status;
489
490         /*
491          * If there is no IRQ handler or it was disabled, exit early.
492          * Since we set PENDING, if another processor is handling
493          * a different instance of this same irq, the other processor
494          * will take care of it.
495          */
496         if (unlikely(!action))
497                 goto out;
498
499         /*
500          * Edge triggered interrupts need to remember
501          * pending events.
502          * This applies to any hw interrupts that allow a second
503          * instance of the same irq to arrive while we are in do_IRQ
504          * or in the handler. But the code here only handles the _second_
505          * instance of the irq, not the third or fourth. So it is mostly
506          * useful for irq hardware that does not mask cleanly in an
507          * SMP environment.
508          */
509         for (;;) {
510                 irqreturn_t action_ret;
511
512                 spin_unlock(&desc->lock);
513
514                 action_ret = handle_IRQ_event(irq, action);
515                 if (!noirqdebug)
516                         note_interrupt(irq, desc, action_ret);
517
518                 spin_lock(&desc->lock);
519                 if (likely(!(desc->status & IRQ_PENDING)))
520                         break;
521                 desc->status &= ~IRQ_PENDING;
522         }
523         desc->status &= ~IRQ_INPROGRESS;
524
525 out:
526         /*
527          * The ->end() handler has to deal with interrupts which got
528          * disabled while the handler was running.
529          */
530         desc->chip->end(irq);
531         spin_unlock(&desc->lock);
532
533         return 1;
534 }
535 #endif
536
537 void early_init_irq_lock_class(void)
538 {
539         struct irq_desc *desc;
540         int i;
541
542         for_each_irq_desc(i, desc) {
543                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
544         }
545 }
546
547 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
548 {
549         struct irq_desc *desc = irq_to_desc(irq);
550         return desc ? desc->kstat_irqs[cpu] : 0;
551 }
552 EXPORT_SYMBOL(kstat_irqs_cpu);
553