8aa09547f5efe77e9104d02fad0e2f077123887f
[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 static 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 void __init __attribute__((weak)) arch_early_irq_init(void)
60 {
61 }
62
63 #ifdef CONFIG_SPARSE_IRQ
64 static struct irq_desc irq_desc_init = {
65         .irq        = -1,
66         .status     = IRQ_DISABLED,
67         .chip       = &no_irq_chip,
68         .handle_irq = handle_bad_irq,
69         .depth      = 1,
70         .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
71 #ifdef CONFIG_SMP
72         .affinity   = CPU_MASK_ALL
73 #endif
74 };
75
76 static void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
77 {
78         unsigned long bytes;
79         char *ptr;
80         int node;
81
82         /* Compute how many bytes we need per irq and allocate them */
83         bytes = nr * sizeof(unsigned int);
84
85         node = cpu_to_node(cpu);
86         ptr = kzalloc_node(bytes, GFP_ATOMIC, node);
87         printk(KERN_DEBUG "  alloc kstat_irqs on cpu %d node %d\n", cpu, node);
88
89         if (ptr)
90                 desc->kstat_irqs = (unsigned int *)ptr;
91 }
92
93 void __attribute__((weak)) arch_init_chip_data(struct irq_desc *desc, int cpu)
94 {
95 }
96
97 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
98 {
99         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
100         desc->irq = irq;
101 #ifdef CONFIG_SMP
102         desc->cpu = cpu;
103 #endif
104         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
105         init_kstat_irqs(desc, cpu, nr_cpu_ids);
106         if (!desc->kstat_irqs) {
107                 printk(KERN_ERR "can not alloc kstat_irqs\n");
108                 BUG_ON(1);
109         }
110         arch_init_chip_data(desc, cpu);
111 }
112
113 /*
114  * Protect the sparse_irqs:
115  */
116 static DEFINE_SPINLOCK(sparse_irq_lock);
117
118 struct irq_desc *irq_desc_ptrs[NR_IRQS] __read_mostly;
119
120 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
121         [0 ... NR_IRQS_LEGACY-1] = {
122                 .irq        = -1,
123                 .status     = IRQ_DISABLED,
124                 .chip       = &no_irq_chip,
125                 .handle_irq = handle_bad_irq,
126                 .depth      = 1,
127                 .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
128 #ifdef CONFIG_SMP
129                 .affinity   = CPU_MASK_ALL
130 #endif
131         }
132 };
133
134 /* FIXME: use bootmem alloc ...*/
135 static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS];
136
137 void __init early_irq_init(void)
138 {
139         struct irq_desc *desc;
140         int legacy_count;
141         int i;
142
143         desc = irq_desc_legacy;
144         legacy_count = ARRAY_SIZE(irq_desc_legacy);
145
146         for (i = 0; i < legacy_count; i++) {
147                 desc[i].irq = i;
148                 desc[i].kstat_irqs = kstat_irqs_legacy[i];
149
150                 irq_desc_ptrs[i] = desc + i;
151         }
152
153         for (i = legacy_count; i < NR_IRQS; i++)
154                 irq_desc_ptrs[i] = NULL;
155
156         arch_early_irq_init();
157 }
158
159 struct irq_desc *irq_to_desc(unsigned int irq)
160 {
161         return (irq < NR_IRQS) ? irq_desc_ptrs[irq] : NULL;
162 }
163
164 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
165 {
166         struct irq_desc *desc;
167         unsigned long flags;
168         int node;
169
170         if (irq >= NR_IRQS) {
171                 printk(KERN_WARNING "irq >= NR_IRQS in irq_to_desc_alloc: %d %d\n",
172                                 irq, NR_IRQS);
173                 WARN_ON(1);
174                 return NULL;
175         }
176
177         desc = irq_desc_ptrs[irq];
178         if (desc)
179                 return desc;
180
181         spin_lock_irqsave(&sparse_irq_lock, flags);
182
183         /* We have to check it to avoid races with another CPU */
184         desc = irq_desc_ptrs[irq];
185         if (desc)
186                 goto out_unlock;
187
188         node = cpu_to_node(cpu);
189         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
190         printk(KERN_DEBUG "  alloc irq_desc for %d on cpu %d node %d\n",
191                  irq, cpu, node);
192         if (!desc) {
193                 printk(KERN_ERR "can not alloc irq_desc\n");
194                 BUG_ON(1);
195         }
196         init_one_irq_desc(irq, desc, cpu);
197
198         irq_desc_ptrs[irq] = desc;
199
200 out_unlock:
201         spin_unlock_irqrestore(&sparse_irq_lock, flags);
202
203         return desc;
204 }
205
206 #else
207
208 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
209         [0 ... NR_IRQS-1] = {
210                 .status = IRQ_DISABLED,
211                 .chip = &no_irq_chip,
212                 .handle_irq = handle_bad_irq,
213                 .depth = 1,
214                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
215 #ifdef CONFIG_SMP
216                 .affinity = CPU_MASK_ALL
217 #endif
218         }
219 };
220
221 #endif
222
223 /*
224  * What should we do if we get a hw irq event on an illegal vector?
225  * Each architecture has to answer this themself.
226  */
227 static void ack_bad(unsigned int irq)
228 {
229         struct irq_desc *desc = irq_to_desc(irq);
230
231         print_irq_desc(irq, desc);
232         ack_bad_irq(irq);
233 }
234
235 /*
236  * NOP functions
237  */
238 static void noop(unsigned int irq)
239 {
240 }
241
242 static unsigned int noop_ret(unsigned int irq)
243 {
244         return 0;
245 }
246
247 /*
248  * Generic no controller implementation
249  */
250 struct irq_chip no_irq_chip = {
251         .name           = "none",
252         .startup        = noop_ret,
253         .shutdown       = noop,
254         .enable         = noop,
255         .disable        = noop,
256         .ack            = ack_bad,
257         .end            = noop,
258 };
259
260 /*
261  * Generic dummy implementation which can be used for
262  * real dumb interrupt sources
263  */
264 struct irq_chip dummy_irq_chip = {
265         .name           = "dummy",
266         .startup        = noop_ret,
267         .shutdown       = noop,
268         .enable         = noop,
269         .disable        = noop,
270         .ack            = noop,
271         .mask           = noop,
272         .unmask         = noop,
273         .end            = noop,
274 };
275
276 /*
277  * Special, empty irq handler:
278  */
279 irqreturn_t no_action(int cpl, void *dev_id)
280 {
281         return IRQ_NONE;
282 }
283
284 /**
285  * handle_IRQ_event - irq action chain handler
286  * @irq:        the interrupt number
287  * @action:     the interrupt action chain for this irq
288  *
289  * Handles the action chain of an irq event
290  */
291 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
292 {
293         irqreturn_t ret, retval = IRQ_NONE;
294         unsigned int status = 0;
295
296         if (!(action->flags & IRQF_DISABLED))
297                 local_irq_enable_in_hardirq();
298
299         do {
300                 ret = action->handler(irq, action->dev_id);
301                 if (ret == IRQ_HANDLED)
302                         status |= action->flags;
303                 retval |= ret;
304                 action = action->next;
305         } while (action);
306
307         if (status & IRQF_SAMPLE_RANDOM)
308                 add_interrupt_randomness(irq);
309         local_irq_disable();
310
311         return retval;
312 }
313
314 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
315 /**
316  * __do_IRQ - original all in one highlevel IRQ handler
317  * @irq:        the interrupt number
318  *
319  * __do_IRQ handles all normal device IRQ's (the special
320  * SMP cross-CPU interrupts have their own specific
321  * handlers).
322  *
323  * This is the original x86 implementation which is used for every
324  * interrupt type.
325  */
326 unsigned int __do_IRQ(unsigned int irq)
327 {
328         struct irq_desc *desc = irq_to_desc(irq);
329         struct irqaction *action;
330         unsigned int status;
331
332         kstat_incr_irqs_this_cpu(irq, desc);
333
334         if (CHECK_IRQ_PER_CPU(desc->status)) {
335                 irqreturn_t action_ret;
336
337                 /*
338                  * No locking required for CPU-local interrupts:
339                  */
340                 if (desc->chip->ack)
341                         desc->chip->ack(irq);
342                 if (likely(!(desc->status & IRQ_DISABLED))) {
343                         action_ret = handle_IRQ_event(irq, desc->action);
344                         if (!noirqdebug)
345                                 note_interrupt(irq, desc, action_ret);
346                 }
347                 desc->chip->end(irq);
348                 return 1;
349         }
350
351         spin_lock(&desc->lock);
352         if (desc->chip->ack)
353                 desc->chip->ack(irq);
354         /*
355          * REPLAY is when Linux resends an IRQ that was dropped earlier
356          * WAITING is used by probe to mark irqs that are being tested
357          */
358         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
359         status |= IRQ_PENDING; /* we _want_ to handle it */
360
361         /*
362          * If the IRQ is disabled for whatever reason, we cannot
363          * use the action we have.
364          */
365         action = NULL;
366         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
367                 action = desc->action;
368                 status &= ~IRQ_PENDING; /* we commit to handling */
369                 status |= IRQ_INPROGRESS; /* we are handling it */
370         }
371         desc->status = status;
372
373         /*
374          * If there is no IRQ handler or it was disabled, exit early.
375          * Since we set PENDING, if another processor is handling
376          * a different instance of this same irq, the other processor
377          * will take care of it.
378          */
379         if (unlikely(!action))
380                 goto out;
381
382         /*
383          * Edge triggered interrupts need to remember
384          * pending events.
385          * This applies to any hw interrupts that allow a second
386          * instance of the same irq to arrive while we are in do_IRQ
387          * or in the handler. But the code here only handles the _second_
388          * instance of the irq, not the third or fourth. So it is mostly
389          * useful for irq hardware that does not mask cleanly in an
390          * SMP environment.
391          */
392         for (;;) {
393                 irqreturn_t action_ret;
394
395                 spin_unlock(&desc->lock);
396
397                 action_ret = handle_IRQ_event(irq, action);
398                 if (!noirqdebug)
399                         note_interrupt(irq, desc, action_ret);
400
401                 spin_lock(&desc->lock);
402                 if (likely(!(desc->status & IRQ_PENDING)))
403                         break;
404                 desc->status &= ~IRQ_PENDING;
405         }
406         desc->status &= ~IRQ_INPROGRESS;
407
408 out:
409         /*
410          * The ->end() handler has to deal with interrupts which got
411          * disabled while the handler was running.
412          */
413         desc->chip->end(irq);
414         spin_unlock(&desc->lock);
415
416         return 1;
417 }
418 #endif
419
420
421 #ifdef CONFIG_TRACE_IRQFLAGS
422 void early_init_irq_lock_class(void)
423 {
424 #ifndef CONFIG_SPARSE_IRQ
425         struct irq_desc *desc;
426         int i;
427
428         for_each_irq_desc(i, desc) {
429                 if (!desc)
430                         continue;
431
432                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
433         }
434 #endif
435 }
436 #endif
437
438 #ifdef CONFIG_SPARSE_IRQ
439 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
440 {
441         struct irq_desc *desc = irq_to_desc(irq);
442         return desc->kstat_irqs[cpu];
443 }
444 #endif
445 EXPORT_SYMBOL(kstat_irqs_cpu);
446