Commit | Line | Data |
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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 | ||
a2166abd TG |
19 | #if defined(CONFIG_NO_IDLE_HZ) && defined(CONFIG_ARM) |
20 | #include <asm/dyntick.h> | |
21 | #endif | |
22 | ||
1da177e4 LT |
23 | #include "internals.h" |
24 | ||
6a6de9ef TG |
25 | /** |
26 | * handle_bad_irq - handle spurious and unhandled irqs | |
27 | */ | |
28 | void fastcall | |
29 | handle_bad_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs) | |
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 | */ | |
34ffdb72 | 50 | struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned = { |
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, |
a53da52f IM |
56 | .lock = SPIN_LOCK_UNLOCKED, |
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 | */ | |
117 | irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs) | |
118 | { | |
119 | return IRQ_NONE; | |
120 | } | |
121 | ||
8d28bc75 IM |
122 | /** |
123 | * handle_IRQ_event - irq action chain handler | |
124 | * @irq: the interrupt number | |
125 | * @regs: pointer to a register structure | |
126 | * @action: the interrupt action chain for this irq | |
127 | * | |
128 | * Handles the action chain of an irq event | |
1da177e4 | 129 | */ |
2e60bbb6 IM |
130 | irqreturn_t handle_IRQ_event(unsigned int irq, struct pt_regs *regs, |
131 | struct irqaction *action) | |
1da177e4 | 132 | { |
908dcecd JB |
133 | irqreturn_t ret, retval = IRQ_NONE; |
134 | unsigned int status = 0; | |
1da177e4 | 135 | |
a2166abd TG |
136 | #if defined(CONFIG_NO_IDLE_HZ) && defined(CONFIG_ARM) |
137 | if (!(action->flags & SA_TIMER) && system_timer->dyn_tick != NULL) { | |
138 | write_seqlock(&xtime_lock); | |
139 | if (system_timer->dyn_tick->state & DYN_TICK_ENABLED) | |
140 | system_timer->dyn_tick->handler(irq, 0, regs); | |
141 | write_sequnlock(&xtime_lock); | |
142 | } | |
143 | #endif | |
144 | ||
3cca53b0 | 145 | if (!(action->flags & IRQF_DISABLED)) |
1da177e4 LT |
146 | local_irq_enable(); |
147 | ||
148 | do { | |
149 | ret = action->handler(irq, action->dev_id, regs); | |
150 | if (ret == IRQ_HANDLED) | |
151 | status |= action->flags; | |
152 | retval |= ret; | |
153 | action = action->next; | |
154 | } while (action); | |
155 | ||
3cca53b0 | 156 | if (status & IRQF_SAMPLE_RANDOM) |
1da177e4 LT |
157 | add_interrupt_randomness(irq); |
158 | local_irq_disable(); | |
159 | ||
160 | return retval; | |
161 | } | |
162 | ||
8d28bc75 IM |
163 | /** |
164 | * __do_IRQ - original all in one highlevel IRQ handler | |
165 | * @irq: the interrupt number | |
166 | * @regs: pointer to a register structure | |
167 | * | |
168 | * __do_IRQ handles all normal device IRQ's (the special | |
1da177e4 LT |
169 | * SMP cross-CPU interrupts have their own specific |
170 | * handlers). | |
8d28bc75 IM |
171 | * |
172 | * This is the original x86 implementation which is used for every | |
173 | * interrupt type. | |
1da177e4 LT |
174 | */ |
175 | fastcall unsigned int __do_IRQ(unsigned int irq, struct pt_regs *regs) | |
176 | { | |
34ffdb72 | 177 | struct irq_desc *desc = irq_desc + irq; |
06fcb0c6 | 178 | struct irqaction *action; |
1da177e4 LT |
179 | unsigned int status; |
180 | ||
181 | kstat_this_cpu.irqs[irq]++; | |
f26fdd59 | 182 | if (CHECK_IRQ_PER_CPU(desc->status)) { |
1da177e4 LT |
183 | irqreturn_t action_ret; |
184 | ||
185 | /* | |
186 | * No locking required for CPU-local interrupts: | |
187 | */ | |
d1bef4ed IM |
188 | if (desc->chip->ack) |
189 | desc->chip->ack(irq); | |
1da177e4 | 190 | action_ret = handle_IRQ_event(irq, regs, desc->action); |
d1bef4ed | 191 | desc->chip->end(irq); |
1da177e4 LT |
192 | return 1; |
193 | } | |
194 | ||
195 | spin_lock(&desc->lock); | |
d1bef4ed IM |
196 | if (desc->chip->ack) |
197 | desc->chip->ack(irq); | |
1da177e4 LT |
198 | /* |
199 | * REPLAY is when Linux resends an IRQ that was dropped earlier | |
200 | * WAITING is used by probe to mark irqs that are being tested | |
201 | */ | |
202 | status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING); | |
203 | status |= IRQ_PENDING; /* we _want_ to handle it */ | |
204 | ||
205 | /* | |
206 | * If the IRQ is disabled for whatever reason, we cannot | |
207 | * use the action we have. | |
208 | */ | |
209 | action = NULL; | |
210 | if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) { | |
211 | action = desc->action; | |
212 | status &= ~IRQ_PENDING; /* we commit to handling */ | |
213 | status |= IRQ_INPROGRESS; /* we are handling it */ | |
214 | } | |
215 | desc->status = status; | |
216 | ||
217 | /* | |
218 | * If there is no IRQ handler or it was disabled, exit early. | |
219 | * Since we set PENDING, if another processor is handling | |
220 | * a different instance of this same irq, the other processor | |
221 | * will take care of it. | |
222 | */ | |
223 | if (unlikely(!action)) | |
224 | goto out; | |
225 | ||
226 | /* | |
227 | * Edge triggered interrupts need to remember | |
228 | * pending events. | |
229 | * This applies to any hw interrupts that allow a second | |
230 | * instance of the same irq to arrive while we are in do_IRQ | |
231 | * or in the handler. But the code here only handles the _second_ | |
232 | * instance of the irq, not the third or fourth. So it is mostly | |
233 | * useful for irq hardware that does not mask cleanly in an | |
234 | * SMP environment. | |
235 | */ | |
236 | for (;;) { | |
237 | irqreturn_t action_ret; | |
238 | ||
239 | spin_unlock(&desc->lock); | |
240 | ||
241 | action_ret = handle_IRQ_event(irq, regs, action); | |
242 | ||
243 | spin_lock(&desc->lock); | |
244 | if (!noirqdebug) | |
200803df | 245 | note_interrupt(irq, desc, action_ret, regs); |
1da177e4 LT |
246 | if (likely(!(desc->status & IRQ_PENDING))) |
247 | break; | |
248 | desc->status &= ~IRQ_PENDING; | |
249 | } | |
250 | desc->status &= ~IRQ_INPROGRESS; | |
251 | ||
252 | out: | |
253 | /* | |
254 | * The ->end() handler has to deal with interrupts which got | |
255 | * disabled while the handler was running. | |
256 | */ | |
d1bef4ed | 257 | desc->chip->end(irq); |
1da177e4 LT |
258 | spin_unlock(&desc->lock); |
259 | ||
260 | return 1; | |
261 | } | |
262 |