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1da177e4 LT |
1 | /* |
2 | * linux/kernel/irq/manage.c | |
3 | * | |
a34db9b2 IM |
4 | * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar |
5 | * Copyright (C) 2005-2006 Thomas Gleixner | |
1da177e4 LT |
6 | * |
7 | * This file contains driver APIs to the irq subsystem. | |
8 | */ | |
9 | ||
b77d6adc | 10 | #include <linux/config.h> |
1da177e4 LT |
11 | #include <linux/irq.h> |
12 | #include <linux/module.h> | |
13 | #include <linux/random.h> | |
14 | #include <linux/interrupt.h> | |
15 | ||
16 | #include "internals.h" | |
17 | ||
18 | #ifdef CONFIG_SMP | |
19 | ||
1da177e4 LT |
20 | /** |
21 | * synchronize_irq - wait for pending IRQ handlers (on other CPUs) | |
1e5d5331 | 22 | * @irq: interrupt number to wait for |
1da177e4 LT |
23 | * |
24 | * This function waits for any pending IRQ handlers for this interrupt | |
25 | * to complete before returning. If you use this function while | |
26 | * holding a resource the IRQ handler may need you will deadlock. | |
27 | * | |
28 | * This function may be called - with care - from IRQ context. | |
29 | */ | |
30 | void synchronize_irq(unsigned int irq) | |
31 | { | |
32 | struct irq_desc *desc = irq_desc + irq; | |
33 | ||
c2b5a251 MW |
34 | if (irq >= NR_IRQS) |
35 | return; | |
36 | ||
1da177e4 LT |
37 | while (desc->status & IRQ_INPROGRESS) |
38 | cpu_relax(); | |
39 | } | |
1da177e4 LT |
40 | EXPORT_SYMBOL(synchronize_irq); |
41 | ||
42 | #endif | |
43 | ||
44 | /** | |
45 | * disable_irq_nosync - disable an irq without waiting | |
46 | * @irq: Interrupt to disable | |
47 | * | |
48 | * Disable the selected interrupt line. Disables and Enables are | |
49 | * nested. | |
50 | * Unlike disable_irq(), this function does not ensure existing | |
51 | * instances of the IRQ handler have completed before returning. | |
52 | * | |
53 | * This function may be called from IRQ context. | |
54 | */ | |
55 | void disable_irq_nosync(unsigned int irq) | |
56 | { | |
34ffdb72 | 57 | struct irq_desc *desc = irq_desc + irq; |
1da177e4 LT |
58 | unsigned long flags; |
59 | ||
c2b5a251 MW |
60 | if (irq >= NR_IRQS) |
61 | return; | |
62 | ||
1da177e4 LT |
63 | spin_lock_irqsave(&desc->lock, flags); |
64 | if (!desc->depth++) { | |
65 | desc->status |= IRQ_DISABLED; | |
d1bef4ed | 66 | desc->chip->disable(irq); |
1da177e4 LT |
67 | } |
68 | spin_unlock_irqrestore(&desc->lock, flags); | |
69 | } | |
1da177e4 LT |
70 | EXPORT_SYMBOL(disable_irq_nosync); |
71 | ||
72 | /** | |
73 | * disable_irq - disable an irq and wait for completion | |
74 | * @irq: Interrupt to disable | |
75 | * | |
76 | * Disable the selected interrupt line. Enables and Disables are | |
77 | * nested. | |
78 | * This function waits for any pending IRQ handlers for this interrupt | |
79 | * to complete before returning. If you use this function while | |
80 | * holding a resource the IRQ handler may need you will deadlock. | |
81 | * | |
82 | * This function may be called - with care - from IRQ context. | |
83 | */ | |
84 | void disable_irq(unsigned int irq) | |
85 | { | |
34ffdb72 | 86 | struct irq_desc *desc = irq_desc + irq; |
1da177e4 | 87 | |
c2b5a251 MW |
88 | if (irq >= NR_IRQS) |
89 | return; | |
90 | ||
1da177e4 LT |
91 | disable_irq_nosync(irq); |
92 | if (desc->action) | |
93 | synchronize_irq(irq); | |
94 | } | |
1da177e4 LT |
95 | EXPORT_SYMBOL(disable_irq); |
96 | ||
97 | /** | |
98 | * enable_irq - enable handling of an irq | |
99 | * @irq: Interrupt to enable | |
100 | * | |
101 | * Undoes the effect of one call to disable_irq(). If this | |
102 | * matches the last disable, processing of interrupts on this | |
103 | * IRQ line is re-enabled. | |
104 | * | |
105 | * This function may be called from IRQ context. | |
106 | */ | |
107 | void enable_irq(unsigned int irq) | |
108 | { | |
34ffdb72 | 109 | struct irq_desc *desc = irq_desc + irq; |
1da177e4 LT |
110 | unsigned long flags; |
111 | ||
c2b5a251 MW |
112 | if (irq >= NR_IRQS) |
113 | return; | |
114 | ||
1da177e4 LT |
115 | spin_lock_irqsave(&desc->lock, flags); |
116 | switch (desc->depth) { | |
117 | case 0: | |
096c8131 | 118 | printk(KERN_WARNING "Unablanced enable_irq(%d)\n", irq); |
1da177e4 LT |
119 | WARN_ON(1); |
120 | break; | |
121 | case 1: { | |
3418d724 TG |
122 | unsigned int status = desc->status & ~IRQ_DISABLED; |
123 | ||
124 | /* Prevent probing on this irq: */ | |
125 | desc->status = status | IRQ_NOPROBE; | |
a4633adc | 126 | check_irq_resend(desc, irq); |
1da177e4 LT |
127 | /* fall-through */ |
128 | } | |
129 | default: | |
130 | desc->depth--; | |
131 | } | |
132 | spin_unlock_irqrestore(&desc->lock, flags); | |
133 | } | |
1da177e4 LT |
134 | EXPORT_SYMBOL(enable_irq); |
135 | ||
ba9a2331 TG |
136 | /** |
137 | * set_irq_wake - control irq power management wakeup | |
138 | * @irq: interrupt to control | |
139 | * @on: enable/disable power management wakeup | |
140 | * | |
141 | * Enable/disable power management wakeup mode | |
142 | */ | |
143 | int set_irq_wake(unsigned int irq, unsigned int on) | |
144 | { | |
145 | struct irq_desc *desc = irq_desc + irq; | |
146 | unsigned long flags; | |
147 | int ret = -ENXIO; | |
148 | ||
149 | spin_lock_irqsave(&desc->lock, flags); | |
150 | if (desc->chip->set_wake) | |
151 | ret = desc->chip->set_wake(irq, on); | |
152 | spin_unlock_irqrestore(&desc->lock, flags); | |
153 | return ret; | |
154 | } | |
155 | EXPORT_SYMBOL(set_irq_wake); | |
156 | ||
1da177e4 LT |
157 | /* |
158 | * Internal function that tells the architecture code whether a | |
159 | * particular irq has been exclusively allocated or is available | |
160 | * for driver use. | |
161 | */ | |
162 | int can_request_irq(unsigned int irq, unsigned long irqflags) | |
163 | { | |
164 | struct irqaction *action; | |
165 | ||
6550c775 | 166 | if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST) |
1da177e4 LT |
167 | return 0; |
168 | ||
169 | action = irq_desc[irq].action; | |
170 | if (action) | |
171 | if (irqflags & action->flags & SA_SHIRQ) | |
172 | action = NULL; | |
173 | ||
174 | return !action; | |
175 | } | |
176 | ||
6a6de9ef TG |
177 | void compat_irq_chip_set_default_handler(struct irq_desc *desc) |
178 | { | |
179 | /* | |
180 | * If the architecture still has not overriden | |
181 | * the flow handler then zap the default. This | |
182 | * should catch incorrect flow-type setting. | |
183 | */ | |
184 | if (desc->handle_irq == &handle_bad_irq) | |
185 | desc->handle_irq = NULL; | |
186 | } | |
187 | ||
1da177e4 LT |
188 | /* |
189 | * Internal function to register an irqaction - typically used to | |
190 | * allocate special interrupts that are part of the architecture. | |
191 | */ | |
06fcb0c6 | 192 | int setup_irq(unsigned int irq, struct irqaction *new) |
1da177e4 LT |
193 | { |
194 | struct irq_desc *desc = irq_desc + irq; | |
195 | struct irqaction *old, **p; | |
196 | unsigned long flags; | |
197 | int shared = 0; | |
198 | ||
c2b5a251 MW |
199 | if (irq >= NR_IRQS) |
200 | return -EINVAL; | |
201 | ||
d1bef4ed | 202 | if (desc->chip == &no_irq_type) |
1da177e4 LT |
203 | return -ENOSYS; |
204 | /* | |
205 | * Some drivers like serial.c use request_irq() heavily, | |
206 | * so we have to be careful not to interfere with a | |
207 | * running system. | |
208 | */ | |
209 | if (new->flags & SA_SAMPLE_RANDOM) { | |
210 | /* | |
211 | * This function might sleep, we want to call it first, | |
212 | * outside of the atomic block. | |
213 | * Yes, this might clear the entropy pool if the wrong | |
214 | * driver is attempted to be loaded, without actually | |
215 | * installing a new handler, but is this really a problem, | |
216 | * only the sysadmin is able to do this. | |
217 | */ | |
218 | rand_initialize_irq(irq); | |
219 | } | |
220 | ||
221 | /* | |
222 | * The following block of code has to be executed atomically | |
223 | */ | |
06fcb0c6 | 224 | spin_lock_irqsave(&desc->lock, flags); |
1da177e4 | 225 | p = &desc->action; |
06fcb0c6 IM |
226 | old = *p; |
227 | if (old) { | |
1da177e4 | 228 | /* Can't share interrupts unless both agree to */ |
f5163427 DS |
229 | if (!(old->flags & new->flags & SA_SHIRQ)) |
230 | goto mismatch; | |
231 | ||
0d7012a9 | 232 | #if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ) |
f5163427 DS |
233 | /* All handlers must agree on per-cpuness */ |
234 | if ((old->flags & IRQ_PER_CPU) != (new->flags & IRQ_PER_CPU)) | |
235 | goto mismatch; | |
236 | #endif | |
1da177e4 LT |
237 | |
238 | /* add new interrupt at end of irq queue */ | |
239 | do { | |
240 | p = &old->next; | |
241 | old = *p; | |
242 | } while (old); | |
243 | shared = 1; | |
244 | } | |
245 | ||
246 | *p = new; | |
0d7012a9 | 247 | #if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ) |
f5163427 DS |
248 | if (new->flags & SA_PERCPU_IRQ) |
249 | desc->status |= IRQ_PER_CPU; | |
250 | #endif | |
1da177e4 | 251 | if (!shared) { |
6a6de9ef TG |
252 | irq_chip_set_defaults(desc->chip); |
253 | compat_irq_chip_set_default_handler(desc); | |
254 | ||
94d39e1f TG |
255 | desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING | |
256 | IRQ_INPROGRESS); | |
257 | ||
258 | if (!(desc->status & IRQ_NOAUTOEN)) { | |
259 | desc->depth = 0; | |
260 | desc->status &= ~IRQ_DISABLED; | |
261 | if (desc->chip->startup) | |
262 | desc->chip->startup(irq); | |
263 | else | |
264 | desc->chip->enable(irq); | |
265 | } | |
1da177e4 | 266 | } |
06fcb0c6 | 267 | spin_unlock_irqrestore(&desc->lock, flags); |
1da177e4 LT |
268 | |
269 | new->irq = irq; | |
270 | register_irq_proc(irq); | |
271 | new->dir = NULL; | |
272 | register_handler_proc(irq, new); | |
273 | ||
274 | return 0; | |
f5163427 DS |
275 | |
276 | mismatch: | |
277 | spin_unlock_irqrestore(&desc->lock, flags); | |
13e87ec6 AM |
278 | if (!(new->flags & SA_PROBEIRQ)) { |
279 | printk(KERN_ERR "%s: irq handler mismatch\n", __FUNCTION__); | |
280 | dump_stack(); | |
281 | } | |
f5163427 | 282 | return -EBUSY; |
1da177e4 LT |
283 | } |
284 | ||
285 | /** | |
286 | * free_irq - free an interrupt | |
287 | * @irq: Interrupt line to free | |
288 | * @dev_id: Device identity to free | |
289 | * | |
290 | * Remove an interrupt handler. The handler is removed and if the | |
291 | * interrupt line is no longer in use by any driver it is disabled. | |
292 | * On a shared IRQ the caller must ensure the interrupt is disabled | |
293 | * on the card it drives before calling this function. The function | |
294 | * does not return until any executing interrupts for this IRQ | |
295 | * have completed. | |
296 | * | |
297 | * This function must not be called from interrupt context. | |
298 | */ | |
299 | void free_irq(unsigned int irq, void *dev_id) | |
300 | { | |
301 | struct irq_desc *desc; | |
302 | struct irqaction **p; | |
303 | unsigned long flags; | |
304 | ||
cd7b24bb | 305 | WARN_ON(in_interrupt()); |
1da177e4 LT |
306 | if (irq >= NR_IRQS) |
307 | return; | |
308 | ||
309 | desc = irq_desc + irq; | |
06fcb0c6 | 310 | spin_lock_irqsave(&desc->lock, flags); |
1da177e4 LT |
311 | p = &desc->action; |
312 | for (;;) { | |
06fcb0c6 | 313 | struct irqaction *action = *p; |
1da177e4 LT |
314 | |
315 | if (action) { | |
316 | struct irqaction **pp = p; | |
317 | ||
318 | p = &action->next; | |
319 | if (action->dev_id != dev_id) | |
320 | continue; | |
321 | ||
322 | /* Found it - now remove it from the list of entries */ | |
323 | *pp = action->next; | |
dbce706e | 324 | |
b77d6adc PBG |
325 | /* Currently used only by UML, might disappear one day.*/ |
326 | #ifdef CONFIG_IRQ_RELEASE_METHOD | |
d1bef4ed IM |
327 | if (desc->chip->release) |
328 | desc->chip->release(irq, dev_id); | |
b77d6adc | 329 | #endif |
dbce706e | 330 | |
1da177e4 LT |
331 | if (!desc->action) { |
332 | desc->status |= IRQ_DISABLED; | |
d1bef4ed IM |
333 | if (desc->chip->shutdown) |
334 | desc->chip->shutdown(irq); | |
1da177e4 | 335 | else |
d1bef4ed | 336 | desc->chip->disable(irq); |
1da177e4 | 337 | } |
06fcb0c6 | 338 | spin_unlock_irqrestore(&desc->lock, flags); |
1da177e4 LT |
339 | unregister_handler_proc(irq, action); |
340 | ||
341 | /* Make sure it's not being used on another CPU */ | |
342 | synchronize_irq(irq); | |
343 | kfree(action); | |
344 | return; | |
345 | } | |
06fcb0c6 IM |
346 | printk(KERN_ERR "Trying to free free IRQ%d\n", irq); |
347 | spin_unlock_irqrestore(&desc->lock, flags); | |
1da177e4 LT |
348 | return; |
349 | } | |
350 | } | |
1da177e4 LT |
351 | EXPORT_SYMBOL(free_irq); |
352 | ||
353 | /** | |
354 | * request_irq - allocate an interrupt line | |
355 | * @irq: Interrupt line to allocate | |
356 | * @handler: Function to be called when the IRQ occurs | |
357 | * @irqflags: Interrupt type flags | |
358 | * @devname: An ascii name for the claiming device | |
359 | * @dev_id: A cookie passed back to the handler function | |
360 | * | |
361 | * This call allocates interrupt resources and enables the | |
362 | * interrupt line and IRQ handling. From the point this | |
363 | * call is made your handler function may be invoked. Since | |
364 | * your handler function must clear any interrupt the board | |
365 | * raises, you must take care both to initialise your hardware | |
366 | * and to set up the interrupt handler in the right order. | |
367 | * | |
368 | * Dev_id must be globally unique. Normally the address of the | |
369 | * device data structure is used as the cookie. Since the handler | |
370 | * receives this value it makes sense to use it. | |
371 | * | |
372 | * If your interrupt is shared you must pass a non NULL dev_id | |
373 | * as this is required when freeing the interrupt. | |
374 | * | |
375 | * Flags: | |
376 | * | |
377 | * SA_SHIRQ Interrupt is shared | |
378 | * SA_INTERRUPT Disable local interrupts while processing | |
379 | * SA_SAMPLE_RANDOM The interrupt can be used for entropy | |
380 | * | |
381 | */ | |
382 | int request_irq(unsigned int irq, | |
383 | irqreturn_t (*handler)(int, void *, struct pt_regs *), | |
06fcb0c6 | 384 | unsigned long irqflags, const char *devname, void *dev_id) |
1da177e4 | 385 | { |
06fcb0c6 | 386 | struct irqaction *action; |
1da177e4 LT |
387 | int retval; |
388 | ||
389 | /* | |
390 | * Sanity-check: shared interrupts must pass in a real dev-ID, | |
391 | * otherwise we'll have trouble later trying to figure out | |
392 | * which interrupt is which (messes up the interrupt freeing | |
393 | * logic etc). | |
394 | */ | |
395 | if ((irqflags & SA_SHIRQ) && !dev_id) | |
396 | return -EINVAL; | |
397 | if (irq >= NR_IRQS) | |
398 | return -EINVAL; | |
6550c775 TG |
399 | if (irq_desc[irq].status & IRQ_NOREQUEST) |
400 | return -EINVAL; | |
1da177e4 LT |
401 | if (!handler) |
402 | return -EINVAL; | |
403 | ||
404 | action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC); | |
405 | if (!action) | |
406 | return -ENOMEM; | |
407 | ||
408 | action->handler = handler; | |
409 | action->flags = irqflags; | |
410 | cpus_clear(action->mask); | |
411 | action->name = devname; | |
412 | action->next = NULL; | |
413 | action->dev_id = dev_id; | |
414 | ||
eee45269 IK |
415 | select_smp_affinity(irq); |
416 | ||
1da177e4 LT |
417 | retval = setup_irq(irq, action); |
418 | if (retval) | |
419 | kfree(action); | |
420 | ||
421 | return retval; | |
422 | } | |
1da177e4 LT |
423 | EXPORT_SYMBOL(request_irq); |
424 |