[SCSI] iscsi class: add session scanning
[linux-2.6] / kernel / irq / chip.c
1 /*
2  * linux/kernel/irq/chip.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, for irq-chip
8  * based architectures.
9  *
10  * Detailed information is available in Documentation/DocBook/genericirq
11  */
12
13 #include <linux/irq.h>
14 #include <linux/msi.h>
15 #include <linux/module.h>
16 #include <linux/interrupt.h>
17 #include <linux/kernel_stat.h>
18
19 #include "internals.h"
20
21 /**
22  *      dynamic_irq_init - initialize a dynamically allocated irq
23  *      @irq:   irq number to initialize
24  */
25 void dynamic_irq_init(unsigned int irq)
26 {
27         struct irq_desc *desc;
28         unsigned long flags;
29
30         if (irq >= NR_IRQS) {
31                 printk(KERN_ERR "Trying to initialize invalid IRQ%d\n", irq);
32                 WARN_ON(1);
33                 return;
34         }
35
36         /* Ensure we don't have left over values from a previous use of this irq */
37         desc = irq_desc + irq;
38         spin_lock_irqsave(&desc->lock, flags);
39         desc->status = IRQ_DISABLED;
40         desc->chip = &no_irq_chip;
41         desc->handle_irq = handle_bad_irq;
42         desc->depth = 1;
43         desc->msi_desc = NULL;
44         desc->handler_data = NULL;
45         desc->chip_data = NULL;
46         desc->action = NULL;
47         desc->irq_count = 0;
48         desc->irqs_unhandled = 0;
49 #ifdef CONFIG_SMP
50         desc->affinity = CPU_MASK_ALL;
51 #endif
52         spin_unlock_irqrestore(&desc->lock, flags);
53 }
54
55 /**
56  *      dynamic_irq_cleanup - cleanup a dynamically allocated irq
57  *      @irq:   irq number to initialize
58  */
59 void dynamic_irq_cleanup(unsigned int irq)
60 {
61         struct irq_desc *desc;
62         unsigned long flags;
63
64         if (irq >= NR_IRQS) {
65                 printk(KERN_ERR "Trying to cleanup invalid IRQ%d\n", irq);
66                 WARN_ON(1);
67                 return;
68         }
69
70         desc = irq_desc + irq;
71         spin_lock_irqsave(&desc->lock, flags);
72         if (desc->action) {
73                 spin_unlock_irqrestore(&desc->lock, flags);
74                 printk(KERN_ERR "Destroying IRQ%d without calling free_irq\n",
75                         irq);
76                 WARN_ON(1);
77                 return;
78         }
79         desc->msi_desc = NULL;
80         desc->handler_data = NULL;
81         desc->chip_data = NULL;
82         desc->handle_irq = handle_bad_irq;
83         desc->chip = &no_irq_chip;
84         spin_unlock_irqrestore(&desc->lock, flags);
85 }
86
87
88 /**
89  *      set_irq_chip - set the irq chip for an irq
90  *      @irq:   irq number
91  *      @chip:  pointer to irq chip description structure
92  */
93 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
94 {
95         struct irq_desc *desc;
96         unsigned long flags;
97
98         if (irq >= NR_IRQS) {
99                 printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
100                 WARN_ON(1);
101                 return -EINVAL;
102         }
103
104         if (!chip)
105                 chip = &no_irq_chip;
106
107         desc = irq_desc + irq;
108         spin_lock_irqsave(&desc->lock, flags);
109         irq_chip_set_defaults(chip);
110         desc->chip = chip;
111         spin_unlock_irqrestore(&desc->lock, flags);
112
113         return 0;
114 }
115 EXPORT_SYMBOL(set_irq_chip);
116
117 /**
118  *      set_irq_type - set the irq type for an irq
119  *      @irq:   irq number
120  *      @type:  interrupt type - see include/linux/interrupt.h
121  */
122 int set_irq_type(unsigned int irq, unsigned int type)
123 {
124         struct irq_desc *desc;
125         unsigned long flags;
126         int ret = -ENXIO;
127
128         if (irq >= NR_IRQS) {
129                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
130                 return -ENODEV;
131         }
132
133         desc = irq_desc + irq;
134         if (desc->chip->set_type) {
135                 spin_lock_irqsave(&desc->lock, flags);
136                 ret = desc->chip->set_type(irq, type);
137                 spin_unlock_irqrestore(&desc->lock, flags);
138         }
139         return ret;
140 }
141 EXPORT_SYMBOL(set_irq_type);
142
143 /**
144  *      set_irq_data - set irq type data for an irq
145  *      @irq:   Interrupt number
146  *      @data:  Pointer to interrupt specific data
147  *
148  *      Set the hardware irq controller data for an irq
149  */
150 int set_irq_data(unsigned int irq, void *data)
151 {
152         struct irq_desc *desc;
153         unsigned long flags;
154
155         if (irq >= NR_IRQS) {
156                 printk(KERN_ERR
157                        "Trying to install controller data for IRQ%d\n", irq);
158                 return -EINVAL;
159         }
160
161         desc = irq_desc + irq;
162         spin_lock_irqsave(&desc->lock, flags);
163         desc->handler_data = data;
164         spin_unlock_irqrestore(&desc->lock, flags);
165         return 0;
166 }
167 EXPORT_SYMBOL(set_irq_data);
168
169 /**
170  *      set_irq_data - set irq type data for an irq
171  *      @irq:   Interrupt number
172  *      @entry: Pointer to MSI descriptor data
173  *
174  *      Set the hardware irq controller data for an irq
175  */
176 int set_irq_msi(unsigned int irq, struct msi_desc *entry)
177 {
178         struct irq_desc *desc;
179         unsigned long flags;
180
181         if (irq >= NR_IRQS) {
182                 printk(KERN_ERR
183                        "Trying to install msi data for IRQ%d\n", irq);
184                 return -EINVAL;
185         }
186         desc = irq_desc + irq;
187         spin_lock_irqsave(&desc->lock, flags);
188         desc->msi_desc = entry;
189         if (entry)
190                 entry->irq = irq;
191         spin_unlock_irqrestore(&desc->lock, flags);
192         return 0;
193 }
194
195 /**
196  *      set_irq_chip_data - set irq chip data for an irq
197  *      @irq:   Interrupt number
198  *      @data:  Pointer to chip specific data
199  *
200  *      Set the hardware irq chip data for an irq
201  */
202 int set_irq_chip_data(unsigned int irq, void *data)
203 {
204         struct irq_desc *desc = irq_desc + irq;
205         unsigned long flags;
206
207         if (irq >= NR_IRQS || !desc->chip) {
208                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
209                 return -EINVAL;
210         }
211
212         spin_lock_irqsave(&desc->lock, flags);
213         desc->chip_data = data;
214         spin_unlock_irqrestore(&desc->lock, flags);
215
216         return 0;
217 }
218 EXPORT_SYMBOL(set_irq_chip_data);
219
220 /*
221  * default enable function
222  */
223 static void default_enable(unsigned int irq)
224 {
225         struct irq_desc *desc = irq_desc + irq;
226
227         desc->chip->unmask(irq);
228         desc->status &= ~IRQ_MASKED;
229 }
230
231 /*
232  * default disable function
233  */
234 static void default_disable(unsigned int irq)
235 {
236 }
237
238 /*
239  * default startup function
240  */
241 static unsigned int default_startup(unsigned int irq)
242 {
243         irq_desc[irq].chip->enable(irq);
244
245         return 0;
246 }
247
248 /*
249  * Fixup enable/disable function pointers
250  */
251 void irq_chip_set_defaults(struct irq_chip *chip)
252 {
253         if (!chip->enable)
254                 chip->enable = default_enable;
255         if (!chip->disable)
256                 chip->disable = default_disable;
257         if (!chip->startup)
258                 chip->startup = default_startup;
259         if (!chip->shutdown)
260                 chip->shutdown = chip->disable;
261         if (!chip->name)
262                 chip->name = chip->typename;
263         if (!chip->end)
264                 chip->end = dummy_irq_chip.end;
265 }
266
267 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
268 {
269         if (desc->chip->mask_ack)
270                 desc->chip->mask_ack(irq);
271         else {
272                 desc->chip->mask(irq);
273                 desc->chip->ack(irq);
274         }
275 }
276
277 /**
278  *      handle_simple_irq - Simple and software-decoded IRQs.
279  *      @irq:   the interrupt number
280  *      @desc:  the interrupt description structure for this irq
281  *
282  *      Simple interrupts are either sent from a demultiplexing interrupt
283  *      handler or come from hardware, where no interrupt hardware control
284  *      is necessary.
285  *
286  *      Note: The caller is expected to handle the ack, clear, mask and
287  *      unmask issues if necessary.
288  */
289 void fastcall
290 handle_simple_irq(unsigned int irq, struct irq_desc *desc)
291 {
292         struct irqaction *action;
293         irqreturn_t action_ret;
294         const unsigned int cpu = smp_processor_id();
295
296         spin_lock(&desc->lock);
297
298         if (unlikely(desc->status & IRQ_INPROGRESS))
299                 goto out_unlock;
300         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
301         kstat_cpu(cpu).irqs[irq]++;
302
303         action = desc->action;
304         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
305                 goto out_unlock;
306
307         desc->status |= IRQ_INPROGRESS;
308         spin_unlock(&desc->lock);
309
310         action_ret = handle_IRQ_event(irq, action);
311         if (!noirqdebug)
312                 note_interrupt(irq, desc, action_ret);
313
314         spin_lock(&desc->lock);
315         desc->status &= ~IRQ_INPROGRESS;
316 out_unlock:
317         spin_unlock(&desc->lock);
318 }
319
320 /**
321  *      handle_level_irq - Level type irq handler
322  *      @irq:   the interrupt number
323  *      @desc:  the interrupt description structure for this irq
324  *
325  *      Level type interrupts are active as long as the hardware line has
326  *      the active level. This may require to mask the interrupt and unmask
327  *      it after the associated handler has acknowledged the device, so the
328  *      interrupt line is back to inactive.
329  */
330 void fastcall
331 handle_level_irq(unsigned int irq, struct irq_desc *desc)
332 {
333         unsigned int cpu = smp_processor_id();
334         struct irqaction *action;
335         irqreturn_t action_ret;
336
337         spin_lock(&desc->lock);
338         mask_ack_irq(desc, irq);
339
340         if (unlikely(desc->status & IRQ_INPROGRESS))
341                 goto out_unlock;
342         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
343         kstat_cpu(cpu).irqs[irq]++;
344
345         /*
346          * If its disabled or no action available
347          * keep it masked and get out of here
348          */
349         action = desc->action;
350         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
351                 goto out_unlock;
352
353         desc->status |= IRQ_INPROGRESS;
354         spin_unlock(&desc->lock);
355
356         action_ret = handle_IRQ_event(irq, action);
357         if (!noirqdebug)
358                 note_interrupt(irq, desc, action_ret);
359
360         spin_lock(&desc->lock);
361         desc->status &= ~IRQ_INPROGRESS;
362         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
363                 desc->chip->unmask(irq);
364 out_unlock:
365         spin_unlock(&desc->lock);
366 }
367
368 /**
369  *      handle_fasteoi_irq - irq handler for transparent controllers
370  *      @irq:   the interrupt number
371  *      @desc:  the interrupt description structure for this irq
372  *
373  *      Only a single callback will be issued to the chip: an ->eoi()
374  *      call when the interrupt has been serviced. This enables support
375  *      for modern forms of interrupt handlers, which handle the flow
376  *      details in hardware, transparently.
377  */
378 void fastcall
379 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
380 {
381         unsigned int cpu = smp_processor_id();
382         struct irqaction *action;
383         irqreturn_t action_ret;
384
385         spin_lock(&desc->lock);
386
387         if (unlikely(desc->status & IRQ_INPROGRESS))
388                 goto out;
389
390         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
391         kstat_cpu(cpu).irqs[irq]++;
392
393         /*
394          * If its disabled or no action available
395          * then mask it and get out of here:
396          */
397         action = desc->action;
398         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
399                 desc->status |= IRQ_PENDING;
400                 if (desc->chip->mask)
401                         desc->chip->mask(irq);
402                 goto out;
403         }
404
405         desc->status |= IRQ_INPROGRESS;
406         desc->status &= ~IRQ_PENDING;
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         desc->status &= ~IRQ_INPROGRESS;
415 out:
416         desc->chip->eoi(irq);
417
418         spin_unlock(&desc->lock);
419 }
420
421 /**
422  *      handle_edge_irq - edge type IRQ handler
423  *      @irq:   the interrupt number
424  *      @desc:  the interrupt description structure for this irq
425  *
426  *      Interrupt occures on the falling and/or rising edge of a hardware
427  *      signal. The occurence is latched into the irq controller hardware
428  *      and must be acked in order to be reenabled. After the ack another
429  *      interrupt can happen on the same source even before the first one
430  *      is handled by the assosiacted event handler. If this happens it
431  *      might be necessary to disable (mask) the interrupt depending on the
432  *      controller hardware. This requires to reenable the interrupt inside
433  *      of the loop which handles the interrupts which have arrived while
434  *      the handler was running. If all pending interrupts are handled, the
435  *      loop is left.
436  */
437 void fastcall
438 handle_edge_irq(unsigned int irq, struct irq_desc *desc)
439 {
440         const unsigned int cpu = smp_processor_id();
441
442         spin_lock(&desc->lock);
443
444         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
445
446         /*
447          * If we're currently running this IRQ, or its disabled,
448          * we shouldn't process the IRQ. Mark it pending, handle
449          * the necessary masking and go out
450          */
451         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
452                     !desc->action)) {
453                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
454                 mask_ack_irq(desc, irq);
455                 goto out_unlock;
456         }
457
458         kstat_cpu(cpu).irqs[irq]++;
459
460         /* Start handling the irq */
461         desc->chip->ack(irq);
462
463         /* Mark the IRQ currently in progress.*/
464         desc->status |= IRQ_INPROGRESS;
465
466         do {
467                 struct irqaction *action = desc->action;
468                 irqreturn_t action_ret;
469
470                 if (unlikely(!action)) {
471                         desc->chip->mask(irq);
472                         goto out_unlock;
473                 }
474
475                 /*
476                  * When another irq arrived while we were handling
477                  * one, we could have masked the irq.
478                  * Renable it, if it was not disabled in meantime.
479                  */
480                 if (unlikely((desc->status &
481                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
482                               (IRQ_PENDING | IRQ_MASKED))) {
483                         desc->chip->unmask(irq);
484                         desc->status &= ~IRQ_MASKED;
485                 }
486
487                 desc->status &= ~IRQ_PENDING;
488                 spin_unlock(&desc->lock);
489                 action_ret = handle_IRQ_event(irq, action);
490                 if (!noirqdebug)
491                         note_interrupt(irq, desc, action_ret);
492                 spin_lock(&desc->lock);
493
494         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
495
496         desc->status &= ~IRQ_INPROGRESS;
497 out_unlock:
498         spin_unlock(&desc->lock);
499 }
500
501 /**
502  *      handle_percpu_IRQ - Per CPU local irq handler
503  *      @irq:   the interrupt number
504  *      @desc:  the interrupt description structure for this irq
505  *
506  *      Per CPU interrupts on SMP machines without locking requirements
507  */
508 void fastcall
509 handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
510 {
511         irqreturn_t action_ret;
512
513         kstat_this_cpu.irqs[irq]++;
514
515         if (desc->chip->ack)
516                 desc->chip->ack(irq);
517
518         action_ret = handle_IRQ_event(irq, desc->action);
519         if (!noirqdebug)
520                 note_interrupt(irq, desc, action_ret);
521
522         if (desc->chip->eoi)
523                 desc->chip->eoi(irq);
524 }
525
526 void
527 __set_irq_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
528                   const char *name)
529 {
530         struct irq_desc *desc;
531         unsigned long flags;
532
533         if (irq >= NR_IRQS) {
534                 printk(KERN_ERR
535                        "Trying to install type control for IRQ%d\n", irq);
536                 return;
537         }
538
539         desc = irq_desc + irq;
540
541         if (!handle)
542                 handle = handle_bad_irq;
543         else if (desc->chip == &no_irq_chip) {
544                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
545                        "for IRQ%d\n", is_chained ? "chained " : "", irq);
546                 /*
547                  * Some ARM implementations install a handler for really dumb
548                  * interrupt hardware without setting an irq_chip. This worked
549                  * with the ARM no_irq_chip but the check in setup_irq would
550                  * prevent us to setup the interrupt at all. Switch it to
551                  * dummy_irq_chip for easy transition.
552                  */
553                 desc->chip = &dummy_irq_chip;
554         }
555
556         spin_lock_irqsave(&desc->lock, flags);
557
558         /* Uninstall? */
559         if (handle == handle_bad_irq) {
560                 if (desc->chip != &no_irq_chip)
561                         mask_ack_irq(desc, irq);
562                 desc->status |= IRQ_DISABLED;
563                 desc->depth = 1;
564         }
565         desc->handle_irq = handle;
566         desc->name = name;
567
568         if (handle != handle_bad_irq && is_chained) {
569                 desc->status &= ~IRQ_DISABLED;
570                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
571                 desc->depth = 0;
572                 desc->chip->unmask(irq);
573         }
574         spin_unlock_irqrestore(&desc->lock, flags);
575 }
576
577 void
578 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
579                          irq_flow_handler_t handle)
580 {
581         set_irq_chip(irq, chip);
582         __set_irq_handler(irq, handle, 0, NULL);
583 }
584
585 void
586 set_irq_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
587                               irq_flow_handler_t handle, const char *name)
588 {
589         set_irq_chip(irq, chip);
590         __set_irq_handler(irq, handle, 0, name);
591 }