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1da177e4 LT |
1 | /* |
2 | * linux/kernel/irq/handle.c | |
3 | * | |
4 | * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar | |
5 | * | |
6 | * This file contains the core interrupt handling code. | |
7 | */ | |
8 | ||
9 | #include <linux/irq.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/random.h> | |
12 | #include <linux/interrupt.h> | |
13 | #include <linux/kernel_stat.h> | |
14 | ||
15 | #include "internals.h" | |
16 | ||
17 | /* | |
18 | * Linux has a controller-independent interrupt architecture. | |
19 | * Every controller has a 'controller-template', that is used | |
20 | * by the main code to do the right thing. Each driver-visible | |
06fcb0c6 | 21 | * interrupt source is transparently wired to the appropriate |
1da177e4 LT |
22 | * controller. Thus drivers need not be aware of the |
23 | * interrupt-controller. | |
24 | * | |
25 | * The code is designed to be easily extended with new/different | |
26 | * interrupt controllers, without having to do assembly magic or | |
27 | * having to touch the generic code. | |
28 | * | |
29 | * Controller mappings for all interrupt sources: | |
30 | */ | |
34ffdb72 | 31 | struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned = { |
1da177e4 | 32 | [0 ... NR_IRQS-1] = { |
4f167fb4 | 33 | .status = IRQ_DISABLED, |
d1bef4ed | 34 | .chip = &no_irq_type, |
a53da52f IM |
35 | .lock = SPIN_LOCK_UNLOCKED, |
36 | #ifdef CONFIG_SMP | |
37 | .affinity = CPU_MASK_ALL | |
38 | #endif | |
1da177e4 LT |
39 | } |
40 | }; | |
41 | ||
42 | /* | |
77a5afec IM |
43 | * What should we do if we get a hw irq event on an illegal vector? |
44 | * Each architecture has to answer this themself. | |
1da177e4 | 45 | */ |
77a5afec | 46 | static void ack_bad(unsigned int irq) |
1da177e4 | 47 | { |
1da177e4 LT |
48 | ack_bad_irq(irq); |
49 | } | |
50 | ||
77a5afec IM |
51 | /* |
52 | * NOP functions | |
53 | */ | |
54 | static void noop(unsigned int irq) | |
55 | { | |
56 | } | |
57 | ||
58 | static unsigned int noop_ret(unsigned int irq) | |
59 | { | |
60 | return 0; | |
61 | } | |
62 | ||
63 | /* | |
64 | * Generic no controller implementation | |
65 | */ | |
1da177e4 | 66 | struct hw_interrupt_type no_irq_type = { |
77a5afec IM |
67 | .typename = "none", |
68 | .startup = noop_ret, | |
69 | .shutdown = noop, | |
70 | .enable = noop, | |
71 | .disable = noop, | |
72 | .ack = ack_bad, | |
73 | .end = noop, | |
1da177e4 LT |
74 | }; |
75 | ||
76 | /* | |
77 | * Special, empty irq handler: | |
78 | */ | |
79 | irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs) | |
80 | { | |
81 | return IRQ_NONE; | |
82 | } | |
83 | ||
8d28bc75 IM |
84 | /** |
85 | * handle_IRQ_event - irq action chain handler | |
86 | * @irq: the interrupt number | |
87 | * @regs: pointer to a register structure | |
88 | * @action: the interrupt action chain for this irq | |
89 | * | |
90 | * Handles the action chain of an irq event | |
1da177e4 | 91 | */ |
2e60bbb6 IM |
92 | irqreturn_t handle_IRQ_event(unsigned int irq, struct pt_regs *regs, |
93 | struct irqaction *action) | |
1da177e4 | 94 | { |
908dcecd JB |
95 | irqreturn_t ret, retval = IRQ_NONE; |
96 | unsigned int status = 0; | |
1da177e4 LT |
97 | |
98 | if (!(action->flags & SA_INTERRUPT)) | |
99 | local_irq_enable(); | |
100 | ||
101 | do { | |
102 | ret = action->handler(irq, action->dev_id, regs); | |
103 | if (ret == IRQ_HANDLED) | |
104 | status |= action->flags; | |
105 | retval |= ret; | |
106 | action = action->next; | |
107 | } while (action); | |
108 | ||
109 | if (status & SA_SAMPLE_RANDOM) | |
110 | add_interrupt_randomness(irq); | |
111 | local_irq_disable(); | |
112 | ||
113 | return retval; | |
114 | } | |
115 | ||
8d28bc75 IM |
116 | /** |
117 | * __do_IRQ - original all in one highlevel IRQ handler | |
118 | * @irq: the interrupt number | |
119 | * @regs: pointer to a register structure | |
120 | * | |
121 | * __do_IRQ handles all normal device IRQ's (the special | |
1da177e4 LT |
122 | * SMP cross-CPU interrupts have their own specific |
123 | * handlers). | |
8d28bc75 IM |
124 | * |
125 | * This is the original x86 implementation which is used for every | |
126 | * interrupt type. | |
1da177e4 LT |
127 | */ |
128 | fastcall unsigned int __do_IRQ(unsigned int irq, struct pt_regs *regs) | |
129 | { | |
34ffdb72 | 130 | struct irq_desc *desc = irq_desc + irq; |
06fcb0c6 | 131 | struct irqaction *action; |
1da177e4 LT |
132 | unsigned int status; |
133 | ||
134 | kstat_this_cpu.irqs[irq]++; | |
f26fdd59 | 135 | if (CHECK_IRQ_PER_CPU(desc->status)) { |
1da177e4 LT |
136 | irqreturn_t action_ret; |
137 | ||
138 | /* | |
139 | * No locking required for CPU-local interrupts: | |
140 | */ | |
d1bef4ed IM |
141 | if (desc->chip->ack) |
142 | desc->chip->ack(irq); | |
1da177e4 | 143 | action_ret = handle_IRQ_event(irq, regs, desc->action); |
d1bef4ed | 144 | desc->chip->end(irq); |
1da177e4 LT |
145 | return 1; |
146 | } | |
147 | ||
148 | spin_lock(&desc->lock); | |
d1bef4ed IM |
149 | if (desc->chip->ack) |
150 | desc->chip->ack(irq); | |
1da177e4 LT |
151 | /* |
152 | * REPLAY is when Linux resends an IRQ that was dropped earlier | |
153 | * WAITING is used by probe to mark irqs that are being tested | |
154 | */ | |
155 | status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING); | |
156 | status |= IRQ_PENDING; /* we _want_ to handle it */ | |
157 | ||
158 | /* | |
159 | * If the IRQ is disabled for whatever reason, we cannot | |
160 | * use the action we have. | |
161 | */ | |
162 | action = NULL; | |
163 | if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) { | |
164 | action = desc->action; | |
165 | status &= ~IRQ_PENDING; /* we commit to handling */ | |
166 | status |= IRQ_INPROGRESS; /* we are handling it */ | |
167 | } | |
168 | desc->status = status; | |
169 | ||
170 | /* | |
171 | * If there is no IRQ handler or it was disabled, exit early. | |
172 | * Since we set PENDING, if another processor is handling | |
173 | * a different instance of this same irq, the other processor | |
174 | * will take care of it. | |
175 | */ | |
176 | if (unlikely(!action)) | |
177 | goto out; | |
178 | ||
179 | /* | |
180 | * Edge triggered interrupts need to remember | |
181 | * pending events. | |
182 | * This applies to any hw interrupts that allow a second | |
183 | * instance of the same irq to arrive while we are in do_IRQ | |
184 | * or in the handler. But the code here only handles the _second_ | |
185 | * instance of the irq, not the third or fourth. So it is mostly | |
186 | * useful for irq hardware that does not mask cleanly in an | |
187 | * SMP environment. | |
188 | */ | |
189 | for (;;) { | |
190 | irqreturn_t action_ret; | |
191 | ||
192 | spin_unlock(&desc->lock); | |
193 | ||
194 | action_ret = handle_IRQ_event(irq, regs, action); | |
195 | ||
196 | spin_lock(&desc->lock); | |
197 | if (!noirqdebug) | |
200803df | 198 | note_interrupt(irq, desc, action_ret, regs); |
1da177e4 LT |
199 | if (likely(!(desc->status & IRQ_PENDING))) |
200 | break; | |
201 | desc->status &= ~IRQ_PENDING; | |
202 | } | |
203 | desc->status &= ~IRQ_INPROGRESS; | |
204 | ||
205 | out: | |
206 | /* | |
207 | * The ->end() handler has to deal with interrupts which got | |
208 | * disabled while the handler was running. | |
209 | */ | |
d1bef4ed | 210 | desc->chip->end(irq); |
1da177e4 LT |
211 | spin_unlock(&desc->lock); |
212 | ||
213 | return 1; | |
214 | } | |
215 |