48299a8a22f8cfe16384e432416b88d5f91f6f9b
[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
21 #include "internals.h"
22
23 /*
24  * lockdep: we want to handle all irq_desc locks as a single lock-class:
25  */
26 struct lock_class_key irq_desc_lock_class;
27
28 /**
29  * handle_bad_irq - handle spurious and unhandled irqs
30  * @irq:       the interrupt number
31  * @desc:      description of the interrupt
32  *
33  * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
34  */
35 void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
36 {
37         print_irq_desc(irq, desc);
38         kstat_incr_irqs_this_cpu(irq, desc);
39         ack_bad_irq(irq);
40 }
41
42 /*
43  * Linux has a controller-independent interrupt architecture.
44  * Every controller has a 'controller-template', that is used
45  * by the main code to do the right thing. Each driver-visible
46  * interrupt source is transparently wired to the appropriate
47  * controller. Thus drivers need not be aware of the
48  * interrupt-controller.
49  *
50  * The code is designed to be easily extended with new/different
51  * interrupt controllers, without having to do assembly magic or
52  * having to touch the generic code.
53  *
54  * Controller mappings for all interrupt sources:
55  */
56 int nr_irqs = NR_IRQS;
57 EXPORT_SYMBOL_GPL(nr_irqs);
58
59 #ifdef CONFIG_SPARSE_IRQ
60 static struct irq_desc irq_desc_init = {
61         .irq        = -1,
62         .status     = IRQ_DISABLED,
63         .chip       = &no_irq_chip,
64         .handle_irq = handle_bad_irq,
65         .depth      = 1,
66         .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
67 #ifdef CONFIG_SMP
68         .affinity   = CPU_MASK_ALL
69 #endif
70 };
71
72 void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
73 {
74         unsigned long bytes;
75         char *ptr;
76         int node;
77
78         /* Compute how many bytes we need per irq and allocate them */
79         bytes = nr * sizeof(unsigned int);
80
81         node = cpu_to_node(cpu);
82         ptr = kzalloc_node(bytes, GFP_ATOMIC, node);
83         printk(KERN_DEBUG "  alloc kstat_irqs on cpu %d node %d\n", cpu, node);
84
85         if (ptr)
86                 desc->kstat_irqs = (unsigned int *)ptr;
87 }
88
89 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
90 {
91         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
92
93         spin_lock_init(&desc->lock);
94         desc->irq = irq;
95 #ifdef CONFIG_SMP
96         desc->cpu = cpu;
97 #endif
98         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
99         init_kstat_irqs(desc, cpu, nr_cpu_ids);
100         if (!desc->kstat_irqs) {
101                 printk(KERN_ERR "can not alloc kstat_irqs\n");
102                 BUG_ON(1);
103         }
104         arch_init_chip_data(desc, cpu);
105 }
106
107 /*
108  * Protect the sparse_irqs:
109  */
110 DEFINE_SPINLOCK(sparse_irq_lock);
111
112 struct irq_desc *irq_desc_ptrs[NR_IRQS] __read_mostly;
113
114 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
115         [0 ... NR_IRQS_LEGACY-1] = {
116                 .irq        = -1,
117                 .status     = IRQ_DISABLED,
118                 .chip       = &no_irq_chip,
119                 .handle_irq = handle_bad_irq,
120                 .depth      = 1,
121                 .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
122 #ifdef CONFIG_SMP
123                 .affinity   = CPU_MASK_ALL
124 #endif
125         }
126 };
127
128 /* FIXME: use bootmem alloc ...*/
129 static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS];
130
131 int __init early_irq_init(void)
132 {
133         struct irq_desc *desc;
134         int legacy_count;
135         int i;
136
137         desc = irq_desc_legacy;
138         legacy_count = ARRAY_SIZE(irq_desc_legacy);
139
140         for (i = 0; i < legacy_count; i++) {
141                 desc[i].irq = i;
142                 desc[i].kstat_irqs = kstat_irqs_legacy[i];
143                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
144
145                 irq_desc_ptrs[i] = desc + i;
146         }
147
148         for (i = legacy_count; i < NR_IRQS; i++)
149                 irq_desc_ptrs[i] = NULL;
150
151         return arch_early_irq_init();
152 }
153
154 struct irq_desc *irq_to_desc(unsigned int irq)
155 {
156         return (irq < NR_IRQS) ? irq_desc_ptrs[irq] : NULL;
157 }
158
159 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
160 {
161         struct irq_desc *desc;
162         unsigned long flags;
163         int node;
164
165         if (irq >= NR_IRQS) {
166                 printk(KERN_WARNING "irq >= NR_IRQS in irq_to_desc_alloc: %d %d\n",
167                                 irq, NR_IRQS);
168                 WARN_ON(1);
169                 return NULL;
170         }
171
172         desc = irq_desc_ptrs[irq];
173         if (desc)
174                 return desc;
175
176         spin_lock_irqsave(&sparse_irq_lock, flags);
177
178         /* We have to check it to avoid races with another CPU */
179         desc = irq_desc_ptrs[irq];
180         if (desc)
181                 goto out_unlock;
182
183         node = cpu_to_node(cpu);
184         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
185         printk(KERN_DEBUG "  alloc irq_desc for %d on cpu %d node %d\n",
186                  irq, cpu, node);
187         if (!desc) {
188                 printk(KERN_ERR "can not alloc irq_desc\n");
189                 BUG_ON(1);
190         }
191         init_one_irq_desc(irq, desc, cpu);
192
193         irq_desc_ptrs[irq] = desc;
194
195 out_unlock:
196         spin_unlock_irqrestore(&sparse_irq_lock, flags);
197
198         return desc;
199 }
200
201 #else /* !CONFIG_SPARSE_IRQ */
202
203 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
204         [0 ... NR_IRQS-1] = {
205                 .status = IRQ_DISABLED,
206                 .chip = &no_irq_chip,
207                 .handle_irq = handle_bad_irq,
208                 .depth = 1,
209                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
210 #ifdef CONFIG_SMP
211                 .affinity = CPU_MASK_ALL
212 #endif
213         }
214 };
215
216 static unsigned int kstat_irqs_all[NR_IRQS][NR_CPUS];
217 int __init early_irq_init(void)
218 {
219         struct irq_desc *desc;
220         int count;
221         int i;
222
223         desc = irq_desc;
224         count = ARRAY_SIZE(irq_desc);
225
226         for (i = 0; i < count; i++) {
227                 desc[i].irq = i;
228                 desc[i].kstat_irqs = kstat_irqs_all[i];
229         }
230
231         return arch_early_irq_init();
232 }
233
234 struct irq_desc *irq_to_desc(unsigned int irq)
235 {
236         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
237 }
238
239 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
240 {
241         return irq_to_desc(irq);
242 }
243 #endif /* !CONFIG_SPARSE_IRQ */
244
245 /*
246  * What should we do if we get a hw irq event on an illegal vector?
247  * Each architecture has to answer this themself.
248  */
249 static void ack_bad(unsigned int irq)
250 {
251         struct irq_desc *desc = irq_to_desc(irq);
252
253         print_irq_desc(irq, desc);
254         ack_bad_irq(irq);
255 }
256
257 /*
258  * NOP functions
259  */
260 static void noop(unsigned int irq)
261 {
262 }
263
264 static unsigned int noop_ret(unsigned int irq)
265 {
266         return 0;
267 }
268
269 /*
270  * Generic no controller implementation
271  */
272 struct irq_chip no_irq_chip = {
273         .name           = "none",
274         .startup        = noop_ret,
275         .shutdown       = noop,
276         .enable         = noop,
277         .disable        = noop,
278         .ack            = ack_bad,
279         .end            = noop,
280 };
281
282 /*
283  * Generic dummy implementation which can be used for
284  * real dumb interrupt sources
285  */
286 struct irq_chip dummy_irq_chip = {
287         .name           = "dummy",
288         .startup        = noop_ret,
289         .shutdown       = noop,
290         .enable         = noop,
291         .disable        = noop,
292         .ack            = noop,
293         .mask           = noop,
294         .unmask         = noop,
295         .end            = noop,
296 };
297
298 /*
299  * Special, empty irq handler:
300  */
301 irqreturn_t no_action(int cpl, void *dev_id)
302 {
303         return IRQ_NONE;
304 }
305
306 /**
307  * handle_IRQ_event - irq action chain handler
308  * @irq:        the interrupt number
309  * @action:     the interrupt action chain for this irq
310  *
311  * Handles the action chain of an irq event
312  */
313 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
314 {
315         irqreturn_t ret, retval = IRQ_NONE;
316         unsigned int status = 0;
317
318         if (!(action->flags & IRQF_DISABLED))
319                 local_irq_enable_in_hardirq();
320
321         do {
322                 ret = action->handler(irq, action->dev_id);
323                 if (ret == IRQ_HANDLED)
324                         status |= action->flags;
325                 retval |= ret;
326                 action = action->next;
327         } while (action);
328
329         if (status & IRQF_SAMPLE_RANDOM)
330                 add_interrupt_randomness(irq);
331         local_irq_disable();
332
333         return retval;
334 }
335
336 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
337 /**
338  * __do_IRQ - original all in one highlevel IRQ handler
339  * @irq:        the interrupt number
340  *
341  * __do_IRQ handles all normal device IRQ's (the special
342  * SMP cross-CPU interrupts have their own specific
343  * handlers).
344  *
345  * This is the original x86 implementation which is used for every
346  * interrupt type.
347  */
348 unsigned int __do_IRQ(unsigned int irq)
349 {
350         struct irq_desc *desc = irq_to_desc(irq);
351         struct irqaction *action;
352         unsigned int status;
353
354         kstat_incr_irqs_this_cpu(irq, desc);
355
356         if (CHECK_IRQ_PER_CPU(desc->status)) {
357                 irqreturn_t action_ret;
358
359                 /*
360                  * No locking required for CPU-local interrupts:
361                  */
362                 if (desc->chip->ack) {
363                         desc->chip->ack(irq);
364                         /* get new one */
365                         desc = irq_remap_to_desc(irq, desc);
366                 }
367                 if (likely(!(desc->status & IRQ_DISABLED))) {
368                         action_ret = handle_IRQ_event(irq, desc->action);
369                         if (!noirqdebug)
370                                 note_interrupt(irq, desc, action_ret);
371                 }
372                 desc->chip->end(irq);
373                 return 1;
374         }
375
376         spin_lock(&desc->lock);
377         if (desc->chip->ack) {
378                 desc->chip->ack(irq);
379                 desc = irq_remap_to_desc(irq, desc);
380         }
381         /*
382          * REPLAY is when Linux resends an IRQ that was dropped earlier
383          * WAITING is used by probe to mark irqs that are being tested
384          */
385         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
386         status |= IRQ_PENDING; /* we _want_ to handle it */
387
388         /*
389          * If the IRQ is disabled for whatever reason, we cannot
390          * use the action we have.
391          */
392         action = NULL;
393         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
394                 action = desc->action;
395                 status &= ~IRQ_PENDING; /* we commit to handling */
396                 status |= IRQ_INPROGRESS; /* we are handling it */
397         }
398         desc->status = status;
399
400         /*
401          * If there is no IRQ handler or it was disabled, exit early.
402          * Since we set PENDING, if another processor is handling
403          * a different instance of this same irq, the other processor
404          * will take care of it.
405          */
406         if (unlikely(!action))
407                 goto out;
408
409         /*
410          * Edge triggered interrupts need to remember
411          * pending events.
412          * This applies to any hw interrupts that allow a second
413          * instance of the same irq to arrive while we are in do_IRQ
414          * or in the handler. But the code here only handles the _second_
415          * instance of the irq, not the third or fourth. So it is mostly
416          * useful for irq hardware that does not mask cleanly in an
417          * SMP environment.
418          */
419         for (;;) {
420                 irqreturn_t action_ret;
421
422                 spin_unlock(&desc->lock);
423
424                 action_ret = handle_IRQ_event(irq, action);
425                 if (!noirqdebug)
426                         note_interrupt(irq, desc, action_ret);
427
428                 spin_lock(&desc->lock);
429                 if (likely(!(desc->status & IRQ_PENDING)))
430                         break;
431                 desc->status &= ~IRQ_PENDING;
432         }
433         desc->status &= ~IRQ_INPROGRESS;
434
435 out:
436         /*
437          * The ->end() handler has to deal with interrupts which got
438          * disabled while the handler was running.
439          */
440         desc->chip->end(irq);
441         spin_unlock(&desc->lock);
442
443         return 1;
444 }
445 #endif
446
447 void early_init_irq_lock_class(void)
448 {
449         struct irq_desc *desc;
450         int i;
451
452         for_each_irq_desc(i, desc) {
453                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
454         }
455 }
456
457 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
458 {
459         struct irq_desc *desc = irq_to_desc(irq);
460         return desc ? desc->kstat_irqs[cpu] : 0;
461 }
462 EXPORT_SYMBOL(kstat_irqs_cpu);
463