06b05a4d30078dc173d10bd6ead90bc52101f8e8
[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 void __attribute__((weak)) arch_init_chip_data(struct irq_desc *desc, int cpu)
90 {
91 }
92
93 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
94 {
95         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
96         desc->irq = irq;
97 #ifdef CONFIG_SMP
98         desc->cpu = cpu;
99 #endif
100         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
101         init_kstat_irqs(desc, cpu, nr_cpu_ids);
102         if (!desc->kstat_irqs) {
103                 printk(KERN_ERR "can not alloc kstat_irqs\n");
104                 BUG_ON(1);
105         }
106         arch_init_chip_data(desc, cpu);
107 }
108
109 /*
110  * Protect the sparse_irqs:
111  */
112 DEFINE_SPINLOCK(sparse_irq_lock);
113
114 struct irq_desc *irq_desc_ptrs[NR_IRQS] __read_mostly;
115
116 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
117         [0 ... NR_IRQS_LEGACY-1] = {
118                 .irq        = -1,
119                 .status     = IRQ_DISABLED,
120                 .chip       = &no_irq_chip,
121                 .handle_irq = handle_bad_irq,
122                 .depth      = 1,
123                 .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
124 #ifdef CONFIG_SMP
125                 .affinity   = CPU_MASK_ALL
126 #endif
127         }
128 };
129
130 /* FIXME: use bootmem alloc ...*/
131 static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS];
132
133 void __init early_irq_init(void)
134 {
135         struct irq_desc *desc;
136         int legacy_count;
137         int i;
138
139         desc = irq_desc_legacy;
140         legacy_count = ARRAY_SIZE(irq_desc_legacy);
141
142         for (i = 0; i < legacy_count; i++) {
143                 desc[i].irq = i;
144                 desc[i].kstat_irqs = kstat_irqs_legacy[i];
145
146                 irq_desc_ptrs[i] = desc + i;
147         }
148
149         for (i = legacy_count; i < NR_IRQS; i++)
150                 irq_desc_ptrs[i] = NULL;
151
152         arch_early_irq_init();
153 }
154
155 struct irq_desc *irq_to_desc(unsigned int irq)
156 {
157         return (irq < NR_IRQS) ? irq_desc_ptrs[irq] : NULL;
158 }
159
160 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
161 {
162         struct irq_desc *desc;
163         unsigned long flags;
164         int node;
165
166         if (irq >= NR_IRQS) {
167                 printk(KERN_WARNING "irq >= NR_IRQS in irq_to_desc_alloc: %d %d\n",
168                                 irq, NR_IRQS);
169                 WARN_ON(1);
170                 return NULL;
171         }
172
173         desc = irq_desc_ptrs[irq];
174         if (desc)
175                 return desc;
176
177         spin_lock_irqsave(&sparse_irq_lock, flags);
178
179         /* We have to check it to avoid races with another CPU */
180         desc = irq_desc_ptrs[irq];
181         if (desc)
182                 goto out_unlock;
183
184         node = cpu_to_node(cpu);
185         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
186         printk(KERN_DEBUG "  alloc irq_desc for %d on cpu %d node %d\n",
187                  irq, cpu, node);
188         if (!desc) {
189                 printk(KERN_ERR "can not alloc irq_desc\n");
190                 BUG_ON(1);
191         }
192         init_one_irq_desc(irq, desc, cpu);
193
194         irq_desc_ptrs[irq] = desc;
195
196 out_unlock:
197         spin_unlock_irqrestore(&sparse_irq_lock, flags);
198
199         return desc;
200 }
201
202 #else /* !CONFIG_SPARSE_IRQ */
203
204 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
205         [0 ... NR_IRQS-1] = {
206                 .status = IRQ_DISABLED,
207                 .chip = &no_irq_chip,
208                 .handle_irq = handle_bad_irq,
209                 .depth = 1,
210                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
211 #ifdef CONFIG_SMP
212                 .affinity = CPU_MASK_ALL
213 #endif
214         }
215 };
216
217 struct irq_desc *irq_to_desc(unsigned int irq)
218 {
219         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
220 }
221
222 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
223 {
224         return irq_to_desc(irq);
225 }
226 #endif /* !CONFIG_SPARSE_IRQ */
227
228 /*
229  * What should we do if we get a hw irq event on an illegal vector?
230  * Each architecture has to answer this themself.
231  */
232 static void ack_bad(unsigned int irq)
233 {
234         struct irq_desc *desc = irq_to_desc(irq);
235
236         print_irq_desc(irq, desc);
237         ack_bad_irq(irq);
238 }
239
240 /*
241  * NOP functions
242  */
243 static void noop(unsigned int irq)
244 {
245 }
246
247 static unsigned int noop_ret(unsigned int irq)
248 {
249         return 0;
250 }
251
252 /*
253  * Generic no controller implementation
254  */
255 struct irq_chip no_irq_chip = {
256         .name           = "none",
257         .startup        = noop_ret,
258         .shutdown       = noop,
259         .enable         = noop,
260         .disable        = noop,
261         .ack            = ack_bad,
262         .end            = noop,
263 };
264
265 /*
266  * Generic dummy implementation which can be used for
267  * real dumb interrupt sources
268  */
269 struct irq_chip dummy_irq_chip = {
270         .name           = "dummy",
271         .startup        = noop_ret,
272         .shutdown       = noop,
273         .enable         = noop,
274         .disable        = noop,
275         .ack            = noop,
276         .mask           = noop,
277         .unmask         = noop,
278         .end            = noop,
279 };
280
281 /*
282  * Special, empty irq handler:
283  */
284 irqreturn_t no_action(int cpl, void *dev_id)
285 {
286         return IRQ_NONE;
287 }
288
289 /**
290  * handle_IRQ_event - irq action chain handler
291  * @irq:        the interrupt number
292  * @action:     the interrupt action chain for this irq
293  *
294  * Handles the action chain of an irq event
295  */
296 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
297 {
298         irqreturn_t ret, retval = IRQ_NONE;
299         unsigned int status = 0;
300
301         if (!(action->flags & IRQF_DISABLED))
302                 local_irq_enable_in_hardirq();
303
304         do {
305                 ret = action->handler(irq, action->dev_id);
306                 if (ret == IRQ_HANDLED)
307                         status |= action->flags;
308                 retval |= ret;
309                 action = action->next;
310         } while (action);
311
312         if (status & IRQF_SAMPLE_RANDOM)
313                 add_interrupt_randomness(irq);
314         local_irq_disable();
315
316         return retval;
317 }
318
319 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
320 /**
321  * __do_IRQ - original all in one highlevel IRQ handler
322  * @irq:        the interrupt number
323  *
324  * __do_IRQ handles all normal device IRQ's (the special
325  * SMP cross-CPU interrupts have their own specific
326  * handlers).
327  *
328  * This is the original x86 implementation which is used for every
329  * interrupt type.
330  */
331 unsigned int __do_IRQ(unsigned int irq)
332 {
333         struct irq_desc *desc = irq_to_desc(irq);
334         struct irqaction *action;
335         unsigned int status;
336
337         kstat_incr_irqs_this_cpu(irq, desc);
338
339         if (CHECK_IRQ_PER_CPU(desc->status)) {
340                 irqreturn_t action_ret;
341
342                 /*
343                  * No locking required for CPU-local interrupts:
344                  */
345                 if (desc->chip->ack) {
346                         desc->chip->ack(irq);
347                         /* get new one */
348                         desc = irq_remap_to_desc(irq, desc);
349                 }
350                 if (likely(!(desc->status & IRQ_DISABLED))) {
351                         action_ret = handle_IRQ_event(irq, desc->action);
352                         if (!noirqdebug)
353                                 note_interrupt(irq, desc, action_ret);
354                 }
355                 desc->chip->end(irq);
356                 return 1;
357         }
358
359         spin_lock(&desc->lock);
360         if (desc->chip->ack) {
361                 desc->chip->ack(irq);
362                 desc = irq_remap_to_desc(irq, desc);
363         }
364         /*
365          * REPLAY is when Linux resends an IRQ that was dropped earlier
366          * WAITING is used by probe to mark irqs that are being tested
367          */
368         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
369         status |= IRQ_PENDING; /* we _want_ to handle it */
370
371         /*
372          * If the IRQ is disabled for whatever reason, we cannot
373          * use the action we have.
374          */
375         action = NULL;
376         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
377                 action = desc->action;
378                 status &= ~IRQ_PENDING; /* we commit to handling */
379                 status |= IRQ_INPROGRESS; /* we are handling it */
380         }
381         desc->status = status;
382
383         /*
384          * If there is no IRQ handler or it was disabled, exit early.
385          * Since we set PENDING, if another processor is handling
386          * a different instance of this same irq, the other processor
387          * will take care of it.
388          */
389         if (unlikely(!action))
390                 goto out;
391
392         /*
393          * Edge triggered interrupts need to remember
394          * pending events.
395          * This applies to any hw interrupts that allow a second
396          * instance of the same irq to arrive while we are in do_IRQ
397          * or in the handler. But the code here only handles the _second_
398          * instance of the irq, not the third or fourth. So it is mostly
399          * useful for irq hardware that does not mask cleanly in an
400          * SMP environment.
401          */
402         for (;;) {
403                 irqreturn_t action_ret;
404
405                 spin_unlock(&desc->lock);
406
407                 action_ret = handle_IRQ_event(irq, action);
408                 if (!noirqdebug)
409                         note_interrupt(irq, desc, action_ret);
410
411                 spin_lock(&desc->lock);
412                 if (likely(!(desc->status & IRQ_PENDING)))
413                         break;
414                 desc->status &= ~IRQ_PENDING;
415         }
416         desc->status &= ~IRQ_INPROGRESS;
417
418 out:
419         /*
420          * The ->end() handler has to deal with interrupts which got
421          * disabled while the handler was running.
422          */
423         desc->chip->end(irq);
424         spin_unlock(&desc->lock);
425
426         return 1;
427 }
428 #endif
429
430 void early_init_irq_lock_class(void)
431 {
432         struct irq_desc *desc;
433         int i;
434
435         for_each_irq_desc(i, desc) {
436                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
437         }
438 }
439
440 #ifdef CONFIG_SPARSE_IRQ
441 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
442 {
443         struct irq_desc *desc = irq_to_desc(irq);
444         return desc ? desc->kstat_irqs[cpu] : 0;
445 }
446 #endif
447 EXPORT_SYMBOL(kstat_irqs_cpu);
448