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1da177e4 LT |
1 | /* |
2 | * linux/kernel/irq/handle.c | |
3 | * | |
a34db9b2 IM |
4 | * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar |
5 | * Copyright (C) 2005-2006, Thomas Gleixner, Russell King | |
1da177e4 LT |
6 | * |
7 | * This file contains the core interrupt handling code. | |
a34db9b2 IM |
8 | * |
9 | * Detailed information is available in Documentation/DocBook/genericirq | |
10 | * | |
1da177e4 LT |
11 | */ |
12 | ||
13 | #include <linux/irq.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/random.h> | |
16 | #include <linux/interrupt.h> | |
17 | #include <linux/kernel_stat.h> | |
18 | ||
19 | #include "internals.h" | |
20 | ||
6a6de9ef TG |
21 | /** |
22 | * handle_bad_irq - handle spurious and unhandled irqs | |
43a1dd50 HK |
23 | * @irq: the interrupt number |
24 | * @desc: description of the interrupt | |
43a1dd50 HK |
25 | * |
26 | * Handles spurious and unhandled IRQ's. It also prints a debugmessage. | |
6a6de9ef TG |
27 | */ |
28 | void fastcall | |
7d12e780 | 29 | handle_bad_irq(unsigned int irq, struct irq_desc *desc) |
6a6de9ef | 30 | { |
43f77759 | 31 | print_irq_desc(irq, desc); |
6a6de9ef TG |
32 | kstat_this_cpu.irqs[irq]++; |
33 | ack_bad_irq(irq); | |
34 | } | |
35 | ||
1da177e4 LT |
36 | /* |
37 | * Linux has a controller-independent interrupt architecture. | |
38 | * Every controller has a 'controller-template', that is used | |
39 | * by the main code to do the right thing. Each driver-visible | |
06fcb0c6 | 40 | * interrupt source is transparently wired to the appropriate |
1da177e4 LT |
41 | * controller. Thus drivers need not be aware of the |
42 | * interrupt-controller. | |
43 | * | |
44 | * The code is designed to be easily extended with new/different | |
45 | * interrupt controllers, without having to do assembly magic or | |
46 | * having to touch the generic code. | |
47 | * | |
48 | * Controller mappings for all interrupt sources: | |
49 | */ | |
e729aa16 | 50 | struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = { |
1da177e4 | 51 | [0 ... NR_IRQS-1] = { |
4f167fb4 | 52 | .status = IRQ_DISABLED, |
f1c2662c | 53 | .chip = &no_irq_chip, |
7a55713a | 54 | .handle_irq = handle_bad_irq, |
94d39e1f | 55 | .depth = 1, |
6cfd76a2 | 56 | .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock), |
a53da52f IM |
57 | #ifdef CONFIG_SMP |
58 | .affinity = CPU_MASK_ALL | |
59 | #endif | |
1da177e4 LT |
60 | } |
61 | }; | |
62 | ||
63 | /* | |
77a5afec IM |
64 | * What should we do if we get a hw irq event on an illegal vector? |
65 | * Each architecture has to answer this themself. | |
1da177e4 | 66 | */ |
77a5afec | 67 | static void ack_bad(unsigned int irq) |
1da177e4 | 68 | { |
43f77759 | 69 | print_irq_desc(irq, irq_desc + irq); |
1da177e4 LT |
70 | ack_bad_irq(irq); |
71 | } | |
72 | ||
77a5afec IM |
73 | /* |
74 | * NOP functions | |
75 | */ | |
76 | static void noop(unsigned int irq) | |
77 | { | |
78 | } | |
79 | ||
80 | static unsigned int noop_ret(unsigned int irq) | |
81 | { | |
82 | return 0; | |
83 | } | |
84 | ||
85 | /* | |
86 | * Generic no controller implementation | |
87 | */ | |
f1c2662c IM |
88 | struct irq_chip no_irq_chip = { |
89 | .name = "none", | |
77a5afec IM |
90 | .startup = noop_ret, |
91 | .shutdown = noop, | |
92 | .enable = noop, | |
93 | .disable = noop, | |
94 | .ack = ack_bad, | |
95 | .end = noop, | |
1da177e4 LT |
96 | }; |
97 | ||
f8b5473f TG |
98 | /* |
99 | * Generic dummy implementation which can be used for | |
100 | * real dumb interrupt sources | |
101 | */ | |
102 | struct irq_chip dummy_irq_chip = { | |
103 | .name = "dummy", | |
104 | .startup = noop_ret, | |
105 | .shutdown = noop, | |
106 | .enable = noop, | |
107 | .disable = noop, | |
108 | .ack = noop, | |
109 | .mask = noop, | |
110 | .unmask = noop, | |
111 | .end = noop, | |
112 | }; | |
113 | ||
1da177e4 LT |
114 | /* |
115 | * Special, empty irq handler: | |
116 | */ | |
7d12e780 | 117 | irqreturn_t no_action(int cpl, void *dev_id) |
1da177e4 LT |
118 | { |
119 | return IRQ_NONE; | |
120 | } | |
121 | ||
8d28bc75 IM |
122 | /** |
123 | * handle_IRQ_event - irq action chain handler | |
124 | * @irq: the interrupt number | |
8d28bc75 IM |
125 | * @action: the interrupt action chain for this irq |
126 | * | |
127 | * Handles the action chain of an irq event | |
1da177e4 | 128 | */ |
7d12e780 | 129 | irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action) |
1da177e4 | 130 | { |
908dcecd JB |
131 | irqreturn_t ret, retval = IRQ_NONE; |
132 | unsigned int status = 0; | |
1da177e4 | 133 | |
d061daa0 | 134 | handle_dynamic_tick(action); |
a2166abd | 135 | |
3cca53b0 | 136 | if (!(action->flags & IRQF_DISABLED)) |
366c7f55 | 137 | local_irq_enable_in_hardirq(); |
1da177e4 LT |
138 | |
139 | do { | |
7d12e780 | 140 | ret = action->handler(irq, action->dev_id); |
1da177e4 LT |
141 | if (ret == IRQ_HANDLED) |
142 | status |= action->flags; | |
143 | retval |= ret; | |
144 | action = action->next; | |
145 | } while (action); | |
146 | ||
3cca53b0 | 147 | if (status & IRQF_SAMPLE_RANDOM) |
1da177e4 LT |
148 | add_interrupt_randomness(irq); |
149 | local_irq_disable(); | |
150 | ||
151 | return retval; | |
152 | } | |
153 | ||
af8c65b5 | 154 | #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ |
8d28bc75 IM |
155 | /** |
156 | * __do_IRQ - original all in one highlevel IRQ handler | |
157 | * @irq: the interrupt number | |
8d28bc75 IM |
158 | * |
159 | * __do_IRQ handles all normal device IRQ's (the special | |
1da177e4 LT |
160 | * SMP cross-CPU interrupts have their own specific |
161 | * handlers). | |
8d28bc75 IM |
162 | * |
163 | * This is the original x86 implementation which is used for every | |
164 | * interrupt type. | |
1da177e4 | 165 | */ |
7d12e780 | 166 | fastcall unsigned int __do_IRQ(unsigned int irq) |
1da177e4 | 167 | { |
34ffdb72 | 168 | struct irq_desc *desc = irq_desc + irq; |
06fcb0c6 | 169 | struct irqaction *action; |
1da177e4 LT |
170 | unsigned int status; |
171 | ||
172 | kstat_this_cpu.irqs[irq]++; | |
f26fdd59 | 173 | if (CHECK_IRQ_PER_CPU(desc->status)) { |
1da177e4 LT |
174 | irqreturn_t action_ret; |
175 | ||
176 | /* | |
177 | * No locking required for CPU-local interrupts: | |
178 | */ | |
d1bef4ed IM |
179 | if (desc->chip->ack) |
180 | desc->chip->ack(irq); | |
7d12e780 | 181 | action_ret = handle_IRQ_event(irq, desc->action); |
d85a60d8 BW |
182 | if (!noirqdebug) |
183 | note_interrupt(irq, desc, action_ret); | |
d1bef4ed | 184 | desc->chip->end(irq); |
1da177e4 LT |
185 | return 1; |
186 | } | |
187 | ||
188 | spin_lock(&desc->lock); | |
d1bef4ed IM |
189 | if (desc->chip->ack) |
190 | desc->chip->ack(irq); | |
1da177e4 LT |
191 | /* |
192 | * REPLAY is when Linux resends an IRQ that was dropped earlier | |
193 | * WAITING is used by probe to mark irqs that are being tested | |
194 | */ | |
195 | status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING); | |
196 | status |= IRQ_PENDING; /* we _want_ to handle it */ | |
197 | ||
198 | /* | |
199 | * If the IRQ is disabled for whatever reason, we cannot | |
200 | * use the action we have. | |
201 | */ | |
202 | action = NULL; | |
203 | if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) { | |
204 | action = desc->action; | |
205 | status &= ~IRQ_PENDING; /* we commit to handling */ | |
206 | status |= IRQ_INPROGRESS; /* we are handling it */ | |
207 | } | |
208 | desc->status = status; | |
209 | ||
210 | /* | |
211 | * If there is no IRQ handler or it was disabled, exit early. | |
212 | * Since we set PENDING, if another processor is handling | |
213 | * a different instance of this same irq, the other processor | |
214 | * will take care of it. | |
215 | */ | |
216 | if (unlikely(!action)) | |
217 | goto out; | |
218 | ||
219 | /* | |
220 | * Edge triggered interrupts need to remember | |
221 | * pending events. | |
222 | * This applies to any hw interrupts that allow a second | |
223 | * instance of the same irq to arrive while we are in do_IRQ | |
224 | * or in the handler. But the code here only handles the _second_ | |
225 | * instance of the irq, not the third or fourth. So it is mostly | |
226 | * useful for irq hardware that does not mask cleanly in an | |
227 | * SMP environment. | |
228 | */ | |
229 | for (;;) { | |
230 | irqreturn_t action_ret; | |
231 | ||
232 | spin_unlock(&desc->lock); | |
233 | ||
7d12e780 | 234 | action_ret = handle_IRQ_event(irq, action); |
1da177e4 | 235 | if (!noirqdebug) |
7d12e780 | 236 | note_interrupt(irq, desc, action_ret); |
b42172fc LT |
237 | |
238 | spin_lock(&desc->lock); | |
1da177e4 LT |
239 | if (likely(!(desc->status & IRQ_PENDING))) |
240 | break; | |
241 | desc->status &= ~IRQ_PENDING; | |
242 | } | |
243 | desc->status &= ~IRQ_INPROGRESS; | |
244 | ||
245 | out: | |
246 | /* | |
247 | * The ->end() handler has to deal with interrupts which got | |
248 | * disabled while the handler was running. | |
249 | */ | |
d1bef4ed | 250 | desc->chip->end(irq); |
1da177e4 LT |
251 | spin_unlock(&desc->lock); |
252 | ||
253 | return 1; | |
254 | } | |
af8c65b5 | 255 | #endif |
1da177e4 | 256 | |
243c7621 IM |
257 | #ifdef CONFIG_TRACE_IRQFLAGS |
258 | ||
259 | /* | |
260 | * lockdep: we want to handle all irq_desc locks as a single lock-class: | |
261 | */ | |
262 | static struct lock_class_key irq_desc_lock_class; | |
263 | ||
264 | void early_init_irq_lock_class(void) | |
265 | { | |
266 | int i; | |
267 | ||
268 | for (i = 0; i < NR_IRQS; i++) | |
269 | lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class); | |
270 | } | |
271 | ||
272 | #endif |