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Commit | Line | Data |
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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 | */ | |
29 | void 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 |
39 | EXPORT_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 | */ | |
54 | void 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 |
69 | EXPORT_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 | */ | |
83 | void 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 |
94 | EXPORT_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 | */ | |
106 | void 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: { | |
3418d724 TG |
121 | unsigned int status = desc->status & ~IRQ_DISABLED; |
122 | ||
123 | /* Prevent probing on this irq: */ | |
124 | desc->status = status | IRQ_NOPROBE; | |
a4633adc | 125 | check_irq_resend(desc, irq); |
1da177e4 LT |
126 | /* fall-through */ |
127 | } | |
128 | default: | |
129 | desc->depth--; | |
130 | } | |
131 | spin_unlock_irqrestore(&desc->lock, flags); | |
132 | } | |
1da177e4 LT |
133 | EXPORT_SYMBOL(enable_irq); |
134 | ||
135 | /* | |
136 | * Internal function that tells the architecture code whether a | |
137 | * particular irq has been exclusively allocated or is available | |
138 | * for driver use. | |
139 | */ | |
140 | int can_request_irq(unsigned int irq, unsigned long irqflags) | |
141 | { | |
142 | struct irqaction *action; | |
143 | ||
6550c775 | 144 | if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST) |
1da177e4 LT |
145 | return 0; |
146 | ||
147 | action = irq_desc[irq].action; | |
148 | if (action) | |
149 | if (irqflags & action->flags & SA_SHIRQ) | |
150 | action = NULL; | |
151 | ||
152 | return !action; | |
153 | } | |
154 | ||
155 | /* | |
156 | * Internal function to register an irqaction - typically used to | |
157 | * allocate special interrupts that are part of the architecture. | |
158 | */ | |
06fcb0c6 | 159 | int setup_irq(unsigned int irq, struct irqaction *new) |
1da177e4 LT |
160 | { |
161 | struct irq_desc *desc = irq_desc + irq; | |
162 | struct irqaction *old, **p; | |
163 | unsigned long flags; | |
164 | int shared = 0; | |
165 | ||
c2b5a251 MW |
166 | if (irq >= NR_IRQS) |
167 | return -EINVAL; | |
168 | ||
d1bef4ed | 169 | if (desc->chip == &no_irq_type) |
1da177e4 LT |
170 | return -ENOSYS; |
171 | /* | |
172 | * Some drivers like serial.c use request_irq() heavily, | |
173 | * so we have to be careful not to interfere with a | |
174 | * running system. | |
175 | */ | |
176 | if (new->flags & SA_SAMPLE_RANDOM) { | |
177 | /* | |
178 | * This function might sleep, we want to call it first, | |
179 | * outside of the atomic block. | |
180 | * Yes, this might clear the entropy pool if the wrong | |
181 | * driver is attempted to be loaded, without actually | |
182 | * installing a new handler, but is this really a problem, | |
183 | * only the sysadmin is able to do this. | |
184 | */ | |
185 | rand_initialize_irq(irq); | |
186 | } | |
187 | ||
188 | /* | |
189 | * The following block of code has to be executed atomically | |
190 | */ | |
06fcb0c6 | 191 | spin_lock_irqsave(&desc->lock, flags); |
1da177e4 | 192 | p = &desc->action; |
06fcb0c6 IM |
193 | old = *p; |
194 | if (old) { | |
1da177e4 | 195 | /* Can't share interrupts unless both agree to */ |
f5163427 DS |
196 | if (!(old->flags & new->flags & SA_SHIRQ)) |
197 | goto mismatch; | |
198 | ||
0d7012a9 | 199 | #if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ) |
f5163427 DS |
200 | /* All handlers must agree on per-cpuness */ |
201 | if ((old->flags & IRQ_PER_CPU) != (new->flags & IRQ_PER_CPU)) | |
202 | goto mismatch; | |
203 | #endif | |
1da177e4 LT |
204 | |
205 | /* add new interrupt at end of irq queue */ | |
206 | do { | |
207 | p = &old->next; | |
208 | old = *p; | |
209 | } while (old); | |
210 | shared = 1; | |
211 | } | |
212 | ||
213 | *p = new; | |
0d7012a9 | 214 | #if defined(CONFIG_IRQ_PER_CPU) && defined(SA_PERCPU_IRQ) |
f5163427 DS |
215 | if (new->flags & SA_PERCPU_IRQ) |
216 | desc->status |= IRQ_PER_CPU; | |
217 | #endif | |
1da177e4 LT |
218 | if (!shared) { |
219 | desc->depth = 0; | |
220 | desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | | |
221 | IRQ_WAITING | IRQ_INPROGRESS); | |
d1bef4ed IM |
222 | if (desc->chip->startup) |
223 | desc->chip->startup(irq); | |
1da177e4 | 224 | else |
d1bef4ed | 225 | desc->chip->enable(irq); |
1da177e4 | 226 | } |
06fcb0c6 | 227 | spin_unlock_irqrestore(&desc->lock, flags); |
1da177e4 LT |
228 | |
229 | new->irq = irq; | |
230 | register_irq_proc(irq); | |
231 | new->dir = NULL; | |
232 | register_handler_proc(irq, new); | |
233 | ||
234 | return 0; | |
f5163427 DS |
235 | |
236 | mismatch: | |
237 | spin_unlock_irqrestore(&desc->lock, flags); | |
13e87ec6 AM |
238 | if (!(new->flags & SA_PROBEIRQ)) { |
239 | printk(KERN_ERR "%s: irq handler mismatch\n", __FUNCTION__); | |
240 | dump_stack(); | |
241 | } | |
f5163427 | 242 | return -EBUSY; |
1da177e4 LT |
243 | } |
244 | ||
245 | /** | |
246 | * free_irq - free an interrupt | |
247 | * @irq: Interrupt line to free | |
248 | * @dev_id: Device identity to free | |
249 | * | |
250 | * Remove an interrupt handler. The handler is removed and if the | |
251 | * interrupt line is no longer in use by any driver it is disabled. | |
252 | * On a shared IRQ the caller must ensure the interrupt is disabled | |
253 | * on the card it drives before calling this function. The function | |
254 | * does not return until any executing interrupts for this IRQ | |
255 | * have completed. | |
256 | * | |
257 | * This function must not be called from interrupt context. | |
258 | */ | |
259 | void free_irq(unsigned int irq, void *dev_id) | |
260 | { | |
261 | struct irq_desc *desc; | |
262 | struct irqaction **p; | |
263 | unsigned long flags; | |
264 | ||
cd7b24bb | 265 | WARN_ON(in_interrupt()); |
1da177e4 LT |
266 | if (irq >= NR_IRQS) |
267 | return; | |
268 | ||
269 | desc = irq_desc + irq; | |
06fcb0c6 | 270 | spin_lock_irqsave(&desc->lock, flags); |
1da177e4 LT |
271 | p = &desc->action; |
272 | for (;;) { | |
06fcb0c6 | 273 | struct irqaction *action = *p; |
1da177e4 LT |
274 | |
275 | if (action) { | |
276 | struct irqaction **pp = p; | |
277 | ||
278 | p = &action->next; | |
279 | if (action->dev_id != dev_id) | |
280 | continue; | |
281 | ||
282 | /* Found it - now remove it from the list of entries */ | |
283 | *pp = action->next; | |
dbce706e | 284 | |
b77d6adc PBG |
285 | /* Currently used only by UML, might disappear one day.*/ |
286 | #ifdef CONFIG_IRQ_RELEASE_METHOD | |
d1bef4ed IM |
287 | if (desc->chip->release) |
288 | desc->chip->release(irq, dev_id); | |
b77d6adc | 289 | #endif |
dbce706e | 290 | |
1da177e4 LT |
291 | if (!desc->action) { |
292 | desc->status |= IRQ_DISABLED; | |
d1bef4ed IM |
293 | if (desc->chip->shutdown) |
294 | desc->chip->shutdown(irq); | |
1da177e4 | 295 | else |
d1bef4ed | 296 | desc->chip->disable(irq); |
1da177e4 | 297 | } |
06fcb0c6 | 298 | spin_unlock_irqrestore(&desc->lock, flags); |
1da177e4 LT |
299 | unregister_handler_proc(irq, action); |
300 | ||
301 | /* Make sure it's not being used on another CPU */ | |
302 | synchronize_irq(irq); | |
303 | kfree(action); | |
304 | return; | |
305 | } | |
06fcb0c6 IM |
306 | printk(KERN_ERR "Trying to free free IRQ%d\n", irq); |
307 | spin_unlock_irqrestore(&desc->lock, flags); | |
1da177e4 LT |
308 | return; |
309 | } | |
310 | } | |
1da177e4 LT |
311 | EXPORT_SYMBOL(free_irq); |
312 | ||
313 | /** | |
314 | * request_irq - allocate an interrupt line | |
315 | * @irq: Interrupt line to allocate | |
316 | * @handler: Function to be called when the IRQ occurs | |
317 | * @irqflags: Interrupt type flags | |
318 | * @devname: An ascii name for the claiming device | |
319 | * @dev_id: A cookie passed back to the handler function | |
320 | * | |
321 | * This call allocates interrupt resources and enables the | |
322 | * interrupt line and IRQ handling. From the point this | |
323 | * call is made your handler function may be invoked. Since | |
324 | * your handler function must clear any interrupt the board | |
325 | * raises, you must take care both to initialise your hardware | |
326 | * and to set up the interrupt handler in the right order. | |
327 | * | |
328 | * Dev_id must be globally unique. Normally the address of the | |
329 | * device data structure is used as the cookie. Since the handler | |
330 | * receives this value it makes sense to use it. | |
331 | * | |
332 | * If your interrupt is shared you must pass a non NULL dev_id | |
333 | * as this is required when freeing the interrupt. | |
334 | * | |
335 | * Flags: | |
336 | * | |
337 | * SA_SHIRQ Interrupt is shared | |
338 | * SA_INTERRUPT Disable local interrupts while processing | |
339 | * SA_SAMPLE_RANDOM The interrupt can be used for entropy | |
340 | * | |
341 | */ | |
342 | int request_irq(unsigned int irq, | |
343 | irqreturn_t (*handler)(int, void *, struct pt_regs *), | |
06fcb0c6 | 344 | unsigned long irqflags, const char *devname, void *dev_id) |
1da177e4 | 345 | { |
06fcb0c6 | 346 | struct irqaction *action; |
1da177e4 LT |
347 | int retval; |
348 | ||
349 | /* | |
350 | * Sanity-check: shared interrupts must pass in a real dev-ID, | |
351 | * otherwise we'll have trouble later trying to figure out | |
352 | * which interrupt is which (messes up the interrupt freeing | |
353 | * logic etc). | |
354 | */ | |
355 | if ((irqflags & SA_SHIRQ) && !dev_id) | |
356 | return -EINVAL; | |
357 | if (irq >= NR_IRQS) | |
358 | return -EINVAL; | |
6550c775 TG |
359 | if (irq_desc[irq].status & IRQ_NOREQUEST) |
360 | return -EINVAL; | |
1da177e4 LT |
361 | if (!handler) |
362 | return -EINVAL; | |
363 | ||
364 | action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC); | |
365 | if (!action) | |
366 | return -ENOMEM; | |
367 | ||
368 | action->handler = handler; | |
369 | action->flags = irqflags; | |
370 | cpus_clear(action->mask); | |
371 | action->name = devname; | |
372 | action->next = NULL; | |
373 | action->dev_id = dev_id; | |
374 | ||
eee45269 IK |
375 | select_smp_affinity(irq); |
376 | ||
1da177e4 LT |
377 | retval = setup_irq(irq, action); |
378 | if (retval) | |
379 | kfree(action); | |
380 | ||
381 | return retval; | |
382 | } | |
1da177e4 LT |
383 | EXPORT_SYMBOL(request_irq); |
384 |