[PATCH] genirq: add genirq sw IRQ-retrigger
[deliverable/linux.git] / kernel / irq / manage.c
CommitLineData
1da177e4
LT
1/*
2 * linux/kernel/irq/manage.c
3 *
4 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
5 *
6 * This file contains driver APIs to the irq subsystem.
7 */
8
b77d6adc 9#include <linux/config.h>
1da177e4
LT
10#include <linux/irq.h>
11#include <linux/module.h>
12#include <linux/random.h>
13#include <linux/interrupt.h>
14
15#include "internals.h"
16
17#ifdef CONFIG_SMP
18
1da177e4
LT
19/**
20 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
1e5d5331 21 * @irq: interrupt number to wait for
1da177e4
LT
22 *
23 * This function waits for any pending IRQ handlers for this interrupt
24 * to complete before returning. If you use this function while
25 * holding a resource the IRQ handler may need you will deadlock.
26 *
27 * This function may be called - with care - from IRQ context.
28 */
29void synchronize_irq(unsigned int irq)
30{
31 struct irq_desc *desc = irq_desc + irq;
32
c2b5a251
MW
33 if (irq >= NR_IRQS)
34 return;
35
1da177e4
LT
36 while (desc->status & IRQ_INPROGRESS)
37 cpu_relax();
38}
1da177e4
LT
39EXPORT_SYMBOL(synchronize_irq);
40
41#endif
42
43/**
44 * disable_irq_nosync - disable an irq without waiting
45 * @irq: Interrupt to disable
46 *
47 * Disable the selected interrupt line. Disables and Enables are
48 * nested.
49 * Unlike disable_irq(), this function does not ensure existing
50 * instances of the IRQ handler have completed before returning.
51 *
52 * This function may be called from IRQ context.
53 */
54void disable_irq_nosync(unsigned int irq)
55{
34ffdb72 56 struct irq_desc *desc = irq_desc + irq;
1da177e4
LT
57 unsigned long flags;
58
c2b5a251
MW
59 if (irq >= NR_IRQS)
60 return;
61
1da177e4
LT
62 spin_lock_irqsave(&desc->lock, flags);
63 if (!desc->depth++) {
64 desc->status |= IRQ_DISABLED;
d1bef4ed 65 desc->chip->disable(irq);
1da177e4
LT
66 }
67 spin_unlock_irqrestore(&desc->lock, flags);
68}
1da177e4
LT
69EXPORT_SYMBOL(disable_irq_nosync);
70
71/**
72 * disable_irq - disable an irq and wait for completion
73 * @irq: Interrupt to disable
74 *
75 * Disable the selected interrupt line. Enables and Disables are
76 * nested.
77 * This function waits for any pending IRQ handlers for this interrupt
78 * to complete before returning. If you use this function while
79 * holding a resource the IRQ handler may need you will deadlock.
80 *
81 * This function may be called - with care - from IRQ context.
82 */
83void disable_irq(unsigned int irq)
84{
34ffdb72 85 struct irq_desc *desc = irq_desc + irq;
1da177e4 86
c2b5a251
MW
87 if (irq >= NR_IRQS)
88 return;
89
1da177e4
LT
90 disable_irq_nosync(irq);
91 if (desc->action)
92 synchronize_irq(irq);
93}
1da177e4
LT
94EXPORT_SYMBOL(disable_irq);
95
96/**
97 * enable_irq - enable handling of an irq
98 * @irq: Interrupt to enable
99 *
100 * Undoes the effect of one call to disable_irq(). If this
101 * matches the last disable, processing of interrupts on this
102 * IRQ line is re-enabled.
103 *
104 * This function may be called from IRQ context.
105 */
106void enable_irq(unsigned int irq)
107{
34ffdb72 108 struct irq_desc *desc = irq_desc + irq;
1da177e4
LT
109 unsigned long flags;
110
c2b5a251
MW
111 if (irq >= NR_IRQS)
112 return;
113
1da177e4
LT
114 spin_lock_irqsave(&desc->lock, flags);
115 switch (desc->depth) {
116 case 0:
096c8131 117 printk(KERN_WARNING "Unablanced enable_irq(%d)\n", irq);
1da177e4
LT
118 WARN_ON(1);
119 break;
120 case 1: {
a4633adc 121 check_irq_resend(desc, irq);
1da177e4
LT
122 /* fall-through */
123 }
124 default:
125 desc->depth--;
126 }
127 spin_unlock_irqrestore(&desc->lock, flags);
128}
1da177e4
LT
129EXPORT_SYMBOL(enable_irq);
130
131/*
132 * Internal function that tells the architecture code whether a
133 * particular irq has been exclusively allocated or is available
134 * for driver use.
135 */
136int can_request_irq(unsigned int irq, unsigned long irqflags)
137{
138 struct irqaction *action;
139
140 if (irq >= NR_IRQS)
141 return 0;
142
143 action = irq_desc[irq].action;
144 if (action)
145 if (irqflags & action->flags & SA_SHIRQ)
146 action = NULL;
147
148 return !action;
149}
150
151/*
152 * Internal function to register an irqaction - typically used to
153 * allocate special interrupts that are part of the architecture.
154 */
06fcb0c6 155int setup_irq(unsigned int irq, struct irqaction *new)
1da177e4
LT
156{
157 struct irq_desc *desc = irq_desc + irq;
158 struct irqaction *old, **p;
159 unsigned long flags;
160 int shared = 0;
161
c2b5a251
MW
162 if (irq >= NR_IRQS)
163 return -EINVAL;
164
d1bef4ed 165 if (desc->chip == &no_irq_type)
1da177e4
LT
166 return -ENOSYS;
167 /*
168 * Some drivers like serial.c use request_irq() heavily,
169 * so we have to be careful not to interfere with a
170 * running system.
171 */
172 if (new->flags & SA_SAMPLE_RANDOM) {
173 /*
174 * This function might sleep, we want to call it first,
175 * outside of the atomic block.
176 * Yes, this might clear the entropy pool if the wrong
177 * driver is attempted to be loaded, without actually
178 * installing a new handler, but is this really a problem,
179 * only the sysadmin is able to do this.
180 */
181 rand_initialize_irq(irq);
182 }
183
184 /*
185 * The following block of code has to be executed atomically
186 */
06fcb0c6 187 spin_lock_irqsave(&desc->lock, flags);
1da177e4 188 p = &desc->action;
06fcb0c6
IM
189 old = *p;
190 if (old) {
1da177e4 191 /* Can't share interrupts unless both agree to */
f5163427
DS
192 if (!(old->flags & new->flags & SA_SHIRQ))
193 goto mismatch;
194
0d7012a9 195#if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
f5163427
DS
196 /* All handlers must agree on per-cpuness */
197 if ((old->flags & IRQ_PER_CPU) != (new->flags & IRQ_PER_CPU))
198 goto mismatch;
199#endif
1da177e4
LT
200
201 /* add new interrupt at end of irq queue */
202 do {
203 p = &old->next;
204 old = *p;
205 } while (old);
206 shared = 1;
207 }
208
209 *p = new;
0d7012a9 210#if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ)
f5163427
DS
211 if (new->flags & SA_PERCPU_IRQ)
212 desc->status |= IRQ_PER_CPU;
213#endif
1da177e4
LT
214 if (!shared) {
215 desc->depth = 0;
216 desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT |
217 IRQ_WAITING | IRQ_INPROGRESS);
d1bef4ed
IM
218 if (desc->chip->startup)
219 desc->chip->startup(irq);
1da177e4 220 else
d1bef4ed 221 desc->chip->enable(irq);
1da177e4 222 }
06fcb0c6 223 spin_unlock_irqrestore(&desc->lock, flags);
1da177e4
LT
224
225 new->irq = irq;
226 register_irq_proc(irq);
227 new->dir = NULL;
228 register_handler_proc(irq, new);
229
230 return 0;
f5163427
DS
231
232mismatch:
233 spin_unlock_irqrestore(&desc->lock, flags);
13e87ec6
AM
234 if (!(new->flags & SA_PROBEIRQ)) {
235 printk(KERN_ERR "%s: irq handler mismatch\n", __FUNCTION__);
236 dump_stack();
237 }
f5163427 238 return -EBUSY;
1da177e4
LT
239}
240
241/**
242 * free_irq - free an interrupt
243 * @irq: Interrupt line to free
244 * @dev_id: Device identity to free
245 *
246 * Remove an interrupt handler. The handler is removed and if the
247 * interrupt line is no longer in use by any driver it is disabled.
248 * On a shared IRQ the caller must ensure the interrupt is disabled
249 * on the card it drives before calling this function. The function
250 * does not return until any executing interrupts for this IRQ
251 * have completed.
252 *
253 * This function must not be called from interrupt context.
254 */
255void free_irq(unsigned int irq, void *dev_id)
256{
257 struct irq_desc *desc;
258 struct irqaction **p;
259 unsigned long flags;
260
cd7b24bb 261 WARN_ON(in_interrupt());
1da177e4
LT
262 if (irq >= NR_IRQS)
263 return;
264
265 desc = irq_desc + irq;
06fcb0c6 266 spin_lock_irqsave(&desc->lock, flags);
1da177e4
LT
267 p = &desc->action;
268 for (;;) {
06fcb0c6 269 struct irqaction *action = *p;
1da177e4
LT
270
271 if (action) {
272 struct irqaction **pp = p;
273
274 p = &action->next;
275 if (action->dev_id != dev_id)
276 continue;
277
278 /* Found it - now remove it from the list of entries */
279 *pp = action->next;
dbce706e 280
b77d6adc
PBG
281 /* Currently used only by UML, might disappear one day.*/
282#ifdef CONFIG_IRQ_RELEASE_METHOD
d1bef4ed
IM
283 if (desc->chip->release)
284 desc->chip->release(irq, dev_id);
b77d6adc 285#endif
dbce706e 286
1da177e4
LT
287 if (!desc->action) {
288 desc->status |= IRQ_DISABLED;
d1bef4ed
IM
289 if (desc->chip->shutdown)
290 desc->chip->shutdown(irq);
1da177e4 291 else
d1bef4ed 292 desc->chip->disable(irq);
1da177e4 293 }
06fcb0c6 294 spin_unlock_irqrestore(&desc->lock, flags);
1da177e4
LT
295 unregister_handler_proc(irq, action);
296
297 /* Make sure it's not being used on another CPU */
298 synchronize_irq(irq);
299 kfree(action);
300 return;
301 }
06fcb0c6
IM
302 printk(KERN_ERR "Trying to free free IRQ%d\n", irq);
303 spin_unlock_irqrestore(&desc->lock, flags);
1da177e4
LT
304 return;
305 }
306}
1da177e4
LT
307EXPORT_SYMBOL(free_irq);
308
309/**
310 * request_irq - allocate an interrupt line
311 * @irq: Interrupt line to allocate
312 * @handler: Function to be called when the IRQ occurs
313 * @irqflags: Interrupt type flags
314 * @devname: An ascii name for the claiming device
315 * @dev_id: A cookie passed back to the handler function
316 *
317 * This call allocates interrupt resources and enables the
318 * interrupt line and IRQ handling. From the point this
319 * call is made your handler function may be invoked. Since
320 * your handler function must clear any interrupt the board
321 * raises, you must take care both to initialise your hardware
322 * and to set up the interrupt handler in the right order.
323 *
324 * Dev_id must be globally unique. Normally the address of the
325 * device data structure is used as the cookie. Since the handler
326 * receives this value it makes sense to use it.
327 *
328 * If your interrupt is shared you must pass a non NULL dev_id
329 * as this is required when freeing the interrupt.
330 *
331 * Flags:
332 *
333 * SA_SHIRQ Interrupt is shared
334 * SA_INTERRUPT Disable local interrupts while processing
335 * SA_SAMPLE_RANDOM The interrupt can be used for entropy
336 *
337 */
338int request_irq(unsigned int irq,
339 irqreturn_t (*handler)(int, void *, struct pt_regs *),
06fcb0c6 340 unsigned long irqflags, const char *devname, void *dev_id)
1da177e4 341{
06fcb0c6 342 struct irqaction *action;
1da177e4
LT
343 int retval;
344
345 /*
346 * Sanity-check: shared interrupts must pass in a real dev-ID,
347 * otherwise we'll have trouble later trying to figure out
348 * which interrupt is which (messes up the interrupt freeing
349 * logic etc).
350 */
351 if ((irqflags & SA_SHIRQ) && !dev_id)
352 return -EINVAL;
353 if (irq >= NR_IRQS)
354 return -EINVAL;
355 if (!handler)
356 return -EINVAL;
357
358 action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
359 if (!action)
360 return -ENOMEM;
361
362 action->handler = handler;
363 action->flags = irqflags;
364 cpus_clear(action->mask);
365 action->name = devname;
366 action->next = NULL;
367 action->dev_id = dev_id;
368
eee45269
IK
369 select_smp_affinity(irq);
370
1da177e4
LT
371 retval = setup_irq(irq, action);
372 if (retval)
373 kfree(action);
374
375 return retval;
376}
1da177e4
LT
377EXPORT_SYMBOL(request_irq);
378
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