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: { | |
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 |
129 | EXPORT_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 | */ | |
136 | int 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 | 155 | int 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 | |
232 | mismatch: | |
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 | */ | |
255 | void 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 |
307 | EXPORT_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 | */ | |
338 | int 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 |
377 | EXPORT_SYMBOL(request_irq); |
378 |