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1/*
2 * linux/kernel/irq/autoprobe.c
3 *
4 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
5 *
6 * This file contains the interrupt probing code and driver APIs.
7 */
8
9#include <linux/irq.h>
10#include <linux/module.h>
11#include <linux/interrupt.h>
12#include <linux/delay.h>
13#include <linux/async.h>
14
15#include "internals.h"
16
17/*
18 * Autodetection depends on the fact that any interrupt that
19 * comes in on to an unassigned handler will get stuck with
20 * "IRQS_WAITING" cleared and the interrupt disabled.
21 */
22static DEFINE_MUTEX(probing_active);
23
24/**
25 * probe_irq_on - begin an interrupt autodetect
26 *
27 * Commence probing for an interrupt. The interrupts are scanned
28 * and a mask of potential interrupt lines is returned.
29 *
30 */
31unsigned long probe_irq_on(void)
32{
33 struct irq_desc *desc;
34 unsigned long mask = 0;
35 int i;
36
37 /*
38 * quiesce the kernel, or at least the asynchronous portion
39 */
40 async_synchronize_full();
41 mutex_lock(&probing_active);
42 /*
43 * something may have generated an irq long ago and we want to
44 * flush such a longstanding irq before considering it as spurious.
45 */
46 for_each_irq_desc_reverse(i, desc) {
47 raw_spin_lock_irq(&desc->lock);
48 if (!desc->action && irq_settings_can_probe(desc)) {
49 /*
50 * Some chips need to know about probing in
51 * progress:
52 */
53 if (desc->irq_data.chip->irq_set_type)
54 desc->irq_data.chip->irq_set_type(&desc->irq_data,
55 IRQ_TYPE_PROBE);
56 irq_startup(desc, false);
57 }
58 raw_spin_unlock_irq(&desc->lock);
59 }
60
61 /* Wait for longstanding interrupts to trigger. */
62 msleep(20);
63
64 /*
65 * enable any unassigned irqs
66 * (we must startup again here because if a longstanding irq
67 * happened in the previous stage, it may have masked itself)
68 */
69 for_each_irq_desc_reverse(i, desc) {
70 raw_spin_lock_irq(&desc->lock);
71 if (!desc->action && irq_settings_can_probe(desc)) {
72 desc->istate |= IRQS_AUTODETECT | IRQS_WAITING;
73 if (irq_startup(desc, false))
74 desc->istate |= IRQS_PENDING;
75 }
76 raw_spin_unlock_irq(&desc->lock);
77 }
78
79 /*
80 * Wait for spurious interrupts to trigger
81 */
82 msleep(100);
83
84 /*
85 * Now filter out any obviously spurious interrupts
86 */
87 for_each_irq_desc(i, desc) {
88 raw_spin_lock_irq(&desc->lock);
89
90 if (desc->istate & IRQS_AUTODETECT) {
91 /* It triggered already - consider it spurious. */
92 if (!(desc->istate & IRQS_WAITING)) {
93 desc->istate &= ~IRQS_AUTODETECT;
94 irq_shutdown(desc);
95 } else
96 if (i < 32)
97 mask |= 1 << i;
98 }
99 raw_spin_unlock_irq(&desc->lock);
100 }
101
102 return mask;
103}
104EXPORT_SYMBOL(probe_irq_on);
105
106/**
107 * probe_irq_mask - scan a bitmap of interrupt lines
108 * @val: mask of interrupts to consider
109 *
110 * Scan the interrupt lines and return a bitmap of active
111 * autodetect interrupts. The interrupt probe logic state
112 * is then returned to its previous value.
113 *
114 * Note: we need to scan all the irq's even though we will
115 * only return autodetect irq numbers - just so that we reset
116 * them all to a known state.
117 */
118unsigned int probe_irq_mask(unsigned long val)
119{
120 unsigned int mask = 0;
121 struct irq_desc *desc;
122 int i;
123
124 for_each_irq_desc(i, desc) {
125 raw_spin_lock_irq(&desc->lock);
126 if (desc->istate & IRQS_AUTODETECT) {
127 if (i < 16 && !(desc->istate & IRQS_WAITING))
128 mask |= 1 << i;
129
130 desc->istate &= ~IRQS_AUTODETECT;
131 irq_shutdown(desc);
132 }
133 raw_spin_unlock_irq(&desc->lock);
134 }
135 mutex_unlock(&probing_active);
136
137 return mask & val;
138}
139EXPORT_SYMBOL(probe_irq_mask);
140
141/**
142 * probe_irq_off - end an interrupt autodetect
143 * @val: mask of potential interrupts (unused)
144 *
145 * Scans the unused interrupt lines and returns the line which
146 * appears to have triggered the interrupt. If no interrupt was
147 * found then zero is returned. If more than one interrupt is
148 * found then minus the first candidate is returned to indicate
149 * their is doubt.
150 *
151 * The interrupt probe logic state is returned to its previous
152 * value.
153 *
154 * BUGS: When used in a module (which arguably shouldn't happen)
155 * nothing prevents two IRQ probe callers from overlapping. The
156 * results of this are non-optimal.
157 */
158int probe_irq_off(unsigned long val)
159{
160 int i, irq_found = 0, nr_of_irqs = 0;
161 struct irq_desc *desc;
162
163 for_each_irq_desc(i, desc) {
164 raw_spin_lock_irq(&desc->lock);
165
166 if (desc->istate & IRQS_AUTODETECT) {
167 if (!(desc->istate & IRQS_WAITING)) {
168 if (!nr_of_irqs)
169 irq_found = i;
170 nr_of_irqs++;
171 }
172 desc->istate &= ~IRQS_AUTODETECT;
173 irq_shutdown(desc);
174 }
175 raw_spin_unlock_irq(&desc->lock);
176 }
177 mutex_unlock(&probing_active);
178
179 if (nr_of_irqs > 1)
180 irq_found = -irq_found;
181
182 return irq_found;
183}
184EXPORT_SYMBOL(probe_irq_off);
185
1/*
2 * linux/kernel/irq/autoprobe.c
3 *
4 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
5 *
6 * This file contains the interrupt probing code and driver APIs.
7 */
8
9#include <linux/irq.h>
10#include <linux/module.h>
11#include <linux/interrupt.h>
12#include <linux/delay.h>
13#include <linux/async.h>
14
15#include "internals.h"
16
17/*
18 * Autodetection depends on the fact that any interrupt that
19 * comes in on to an unassigned handler will get stuck with
20 * "IRQS_WAITING" cleared and the interrupt disabled.
21 */
22static DEFINE_MUTEX(probing_active);
23
24/**
25 * probe_irq_on - begin an interrupt autodetect
26 *
27 * Commence probing for an interrupt. The interrupts are scanned
28 * and a mask of potential interrupt lines is returned.
29 *
30 */
31unsigned long probe_irq_on(void)
32{
33 struct irq_desc *desc;
34 unsigned long mask = 0;
35 int i;
36
37 /*
38 * quiesce the kernel, or at least the asynchronous portion
39 */
40 async_synchronize_full();
41 mutex_lock(&probing_active);
42 /*
43 * something may have generated an irq long ago and we want to
44 * flush such a longstanding irq before considering it as spurious.
45 */
46 for_each_irq_desc_reverse(i, desc) {
47 raw_spin_lock_irq(&desc->lock);
48 if (!desc->action && irq_settings_can_probe(desc)) {
49 /*
50 * Some chips need to know about probing in
51 * progress:
52 */
53 if (desc->irq_data.chip->irq_set_type)
54 desc->irq_data.chip->irq_set_type(&desc->irq_data,
55 IRQ_TYPE_PROBE);
56 irq_startup(desc);
57 }
58 raw_spin_unlock_irq(&desc->lock);
59 }
60
61 /* Wait for longstanding interrupts to trigger. */
62 msleep(20);
63
64 /*
65 * enable any unassigned irqs
66 * (we must startup again here because if a longstanding irq
67 * happened in the previous stage, it may have masked itself)
68 */
69 for_each_irq_desc_reverse(i, desc) {
70 raw_spin_lock_irq(&desc->lock);
71 if (!desc->action && irq_settings_can_probe(desc)) {
72 desc->istate |= IRQS_AUTODETECT | IRQS_WAITING;
73 if (irq_startup(desc))
74 desc->istate |= IRQS_PENDING;
75 }
76 raw_spin_unlock_irq(&desc->lock);
77 }
78
79 /*
80 * Wait for spurious interrupts to trigger
81 */
82 msleep(100);
83
84 /*
85 * Now filter out any obviously spurious interrupts
86 */
87 for_each_irq_desc(i, desc) {
88 raw_spin_lock_irq(&desc->lock);
89
90 if (desc->istate & IRQS_AUTODETECT) {
91 /* It triggered already - consider it spurious. */
92 if (!(desc->istate & IRQS_WAITING)) {
93 desc->istate &= ~IRQS_AUTODETECT;
94 irq_shutdown(desc);
95 } else
96 if (i < 32)
97 mask |= 1 << i;
98 }
99 raw_spin_unlock_irq(&desc->lock);
100 }
101
102 return mask;
103}
104EXPORT_SYMBOL(probe_irq_on);
105
106/**
107 * probe_irq_mask - scan a bitmap of interrupt lines
108 * @val: mask of interrupts to consider
109 *
110 * Scan the interrupt lines and return a bitmap of active
111 * autodetect interrupts. The interrupt probe logic state
112 * is then returned to its previous value.
113 *
114 * Note: we need to scan all the irq's even though we will
115 * only return autodetect irq numbers - just so that we reset
116 * them all to a known state.
117 */
118unsigned int probe_irq_mask(unsigned long val)
119{
120 unsigned int mask = 0;
121 struct irq_desc *desc;
122 int i;
123
124 for_each_irq_desc(i, desc) {
125 raw_spin_lock_irq(&desc->lock);
126 if (desc->istate & IRQS_AUTODETECT) {
127 if (i < 16 && !(desc->istate & IRQS_WAITING))
128 mask |= 1 << i;
129
130 desc->istate &= ~IRQS_AUTODETECT;
131 irq_shutdown(desc);
132 }
133 raw_spin_unlock_irq(&desc->lock);
134 }
135 mutex_unlock(&probing_active);
136
137 return mask & val;
138}
139EXPORT_SYMBOL(probe_irq_mask);
140
141/**
142 * probe_irq_off - end an interrupt autodetect
143 * @val: mask of potential interrupts (unused)
144 *
145 * Scans the unused interrupt lines and returns the line which
146 * appears to have triggered the interrupt. If no interrupt was
147 * found then zero is returned. If more than one interrupt is
148 * found then minus the first candidate is returned to indicate
149 * their is doubt.
150 *
151 * The interrupt probe logic state is returned to its previous
152 * value.
153 *
154 * BUGS: When used in a module (which arguably shouldn't happen)
155 * nothing prevents two IRQ probe callers from overlapping. The
156 * results of this are non-optimal.
157 */
158int probe_irq_off(unsigned long val)
159{
160 int i, irq_found = 0, nr_of_irqs = 0;
161 struct irq_desc *desc;
162
163 for_each_irq_desc(i, desc) {
164 raw_spin_lock_irq(&desc->lock);
165
166 if (desc->istate & IRQS_AUTODETECT) {
167 if (!(desc->istate & IRQS_WAITING)) {
168 if (!nr_of_irqs)
169 irq_found = i;
170 nr_of_irqs++;
171 }
172 desc->istate &= ~IRQS_AUTODETECT;
173 irq_shutdown(desc);
174 }
175 raw_spin_unlock_irq(&desc->lock);
176 }
177 mutex_unlock(&probing_active);
178
179 if (nr_of_irqs > 1)
180 irq_found = -irq_found;
181
182 return irq_found;
183}
184EXPORT_SYMBOL(probe_irq_off);
185