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