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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /kernel/irq/handle.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'kernel/irq/handle.c')
-rw-r--r--kernel/irq/handle.c193
1 files changed, 193 insertions, 0 deletions
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
new file mode 100644
index 000000000000..2fb0e46e11f3
--- /dev/null
+++ b/kernel/irq/handle.c
@@ -0,0 +1,193 @@
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
21 * interrupt source is transparently wired to the apropriate
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 */
31irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = {
32 [0 ... NR_IRQS-1] = {
33 .handler = &no_irq_type,
34 .lock = SPIN_LOCK_UNLOCKED
35 }
36};
37
38/*
39 * Generic 'no controller' code
40 */
41static void end_none(unsigned int irq) { }
42static void enable_none(unsigned int irq) { }
43static void disable_none(unsigned int irq) { }
44static void shutdown_none(unsigned int irq) { }
45static unsigned int startup_none(unsigned int irq) { return 0; }
46
47static void ack_none(unsigned int irq)
48{
49 /*
50 * 'what should we do if we get a hw irq event on an illegal vector'.
51 * each architecture has to answer this themself.
52 */
53 ack_bad_irq(irq);
54}
55
56struct hw_interrupt_type no_irq_type = {
57 .typename = "none",
58 .startup = startup_none,
59 .shutdown = shutdown_none,
60 .enable = enable_none,
61 .disable = disable_none,
62 .ack = ack_none,
63 .end = end_none,
64 .set_affinity = NULL
65};
66
67/*
68 * Special, empty irq handler:
69 */
70irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs)
71{
72 return IRQ_NONE;
73}
74
75/*
76 * Have got an event to handle:
77 */
78fastcall int handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
79 struct irqaction *action)
80{
81 int ret, retval = 0, status = 0;
82
83 if (!(action->flags & SA_INTERRUPT))
84 local_irq_enable();
85
86 do {
87 ret = action->handler(irq, action->dev_id, regs);
88 if (ret == IRQ_HANDLED)
89 status |= action->flags;
90 retval |= ret;
91 action = action->next;
92 } while (action);
93
94 if (status & SA_SAMPLE_RANDOM)
95 add_interrupt_randomness(irq);
96 local_irq_disable();
97
98 return retval;
99}
100
101/*
102 * do_IRQ handles all normal device IRQ's (the special
103 * SMP cross-CPU interrupts have their own specific
104 * handlers).
105 */
106fastcall unsigned int __do_IRQ(unsigned int irq, struct pt_regs *regs)
107{
108 irq_desc_t *desc = irq_desc + irq;
109 struct irqaction * action;
110 unsigned int status;
111
112 kstat_this_cpu.irqs[irq]++;
113 if (desc->status & IRQ_PER_CPU) {
114 irqreturn_t action_ret;
115
116 /*
117 * No locking required for CPU-local interrupts:
118 */
119 desc->handler->ack(irq);
120 action_ret = handle_IRQ_event(irq, regs, desc->action);
121 if (!noirqdebug)
122 note_interrupt(irq, desc, action_ret);
123 desc->handler->end(irq);
124 return 1;
125 }
126
127 spin_lock(&desc->lock);
128 desc->handler->ack(irq);
129 /*
130 * REPLAY is when Linux resends an IRQ that was dropped earlier
131 * WAITING is used by probe to mark irqs that are being tested
132 */
133 status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
134 status |= IRQ_PENDING; /* we _want_ to handle it */
135
136 /*
137 * If the IRQ is disabled for whatever reason, we cannot
138 * use the action we have.
139 */
140 action = NULL;
141 if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
142 action = desc->action;
143 status &= ~IRQ_PENDING; /* we commit to handling */
144 status |= IRQ_INPROGRESS; /* we are handling it */
145 }
146 desc->status = status;
147
148 /*
149 * If there is no IRQ handler or it was disabled, exit early.
150 * Since we set PENDING, if another processor is handling
151 * a different instance of this same irq, the other processor
152 * will take care of it.
153 */
154 if (unlikely(!action))
155 goto out;
156
157 /*
158 * Edge triggered interrupts need to remember
159 * pending events.
160 * This applies to any hw interrupts that allow a second
161 * instance of the same irq to arrive while we are in do_IRQ
162 * or in the handler. But the code here only handles the _second_
163 * instance of the irq, not the third or fourth. So it is mostly
164 * useful for irq hardware that does not mask cleanly in an
165 * SMP environment.
166 */
167 for (;;) {
168 irqreturn_t action_ret;
169
170 spin_unlock(&desc->lock);
171
172 action_ret = handle_IRQ_event(irq, regs, action);
173
174 spin_lock(&desc->lock);
175 if (!noirqdebug)
176 note_interrupt(irq, desc, action_ret);
177 if (likely(!(desc->status & IRQ_PENDING)))
178 break;
179 desc->status &= ~IRQ_PENDING;
180 }
181 desc->status &= ~IRQ_INPROGRESS;
182
183out:
184 /*
185 * The ->end() handler has to deal with interrupts which got
186 * disabled while the handler was running.
187 */
188 desc->handler->end(irq);
189 spin_unlock(&desc->lock);
190
191 return 1;
192}
193