1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
>> 2 * linux/kernel/irq/autoprobe.c
>> 3 *
3 * Copyright (C) 1992, 1998-2004 Linus Torvald 4 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
4 * 5 *
5 * This file contains the interrupt probing co 6 * This file contains the interrupt probing code and driver APIs.
6 */ 7 */
7 8
8 #include <linux/irq.h> 9 #include <linux/irq.h>
9 #include <linux/module.h> 10 #include <linux/module.h>
10 #include <linux/interrupt.h> 11 #include <linux/interrupt.h>
11 #include <linux/delay.h> 12 #include <linux/delay.h>
12 #include <linux/async.h> 13 #include <linux/async.h>
13 14
14 #include "internals.h" 15 #include "internals.h"
15 16
16 /* 17 /*
17 * Autodetection depends on the fact that any 18 * Autodetection depends on the fact that any interrupt that
18 * comes in on to an unassigned handler will g 19 * comes in on to an unassigned handler will get stuck with
19 * "IRQS_WAITING" cleared and the interrupt di 20 * "IRQS_WAITING" cleared and the interrupt disabled.
20 */ 21 */
21 static DEFINE_MUTEX(probing_active); 22 static DEFINE_MUTEX(probing_active);
22 23
23 /** 24 /**
24 * probe_irq_on - begin an interrupt a 25 * probe_irq_on - begin an interrupt autodetect
25 * 26 *
26 * Commence probing for an interrupt. The 27 * Commence probing for an interrupt. The interrupts are scanned
27 * and a mask of potential interrupt line 28 * and a mask of potential interrupt lines is returned.
28 * 29 *
29 */ 30 */
30 unsigned long probe_irq_on(void) 31 unsigned long probe_irq_on(void)
31 { 32 {
32 struct irq_desc *desc; 33 struct irq_desc *desc;
33 unsigned long mask = 0; 34 unsigned long mask = 0;
34 int i; 35 int i;
35 36
36 /* 37 /*
37 * quiesce the kernel, or at least the 38 * quiesce the kernel, or at least the asynchronous portion
38 */ 39 */
39 async_synchronize_full(); 40 async_synchronize_full();
40 mutex_lock(&probing_active); 41 mutex_lock(&probing_active);
41 /* 42 /*
42 * something may have generated an irq 43 * something may have generated an irq long ago and we want to
43 * flush such a longstanding irq befor 44 * flush such a longstanding irq before considering it as spurious.
44 */ 45 */
45 for_each_irq_desc_reverse(i, desc) { 46 for_each_irq_desc_reverse(i, desc) {
46 raw_spin_lock_irq(&desc->lock) 47 raw_spin_lock_irq(&desc->lock);
47 if (!desc->action && irq_setti 48 if (!desc->action && irq_settings_can_probe(desc)) {
48 /* 49 /*
49 * Some chips need to 50 * Some chips need to know about probing in
50 * progress: 51 * progress:
51 */ 52 */
52 if (desc->irq_data.chi 53 if (desc->irq_data.chip->irq_set_type)
53 desc->irq_data 54 desc->irq_data.chip->irq_set_type(&desc->irq_data,
54 55 IRQ_TYPE_PROBE);
55 irq_activate_and_start !! 56 irq_startup(desc, IRQ_NORESEND, IRQ_START_FORCE);
56 } 57 }
57 raw_spin_unlock_irq(&desc->loc 58 raw_spin_unlock_irq(&desc->lock);
58 } 59 }
59 60
60 /* Wait for longstanding interrupts to 61 /* Wait for longstanding interrupts to trigger. */
61 msleep(20); 62 msleep(20);
62 63
63 /* 64 /*
64 * enable any unassigned irqs 65 * enable any unassigned irqs
65 * (we must startup again here because 66 * (we must startup again here because if a longstanding irq
66 * happened in the previous stage, it 67 * happened in the previous stage, it may have masked itself)
67 */ 68 */
68 for_each_irq_desc_reverse(i, desc) { 69 for_each_irq_desc_reverse(i, desc) {
69 raw_spin_lock_irq(&desc->lock) 70 raw_spin_lock_irq(&desc->lock);
70 if (!desc->action && irq_setti 71 if (!desc->action && irq_settings_can_probe(desc)) {
71 desc->istate |= IRQS_A 72 desc->istate |= IRQS_AUTODETECT | IRQS_WAITING;
72 if (irq_activate_and_s !! 73 if (irq_startup(desc, IRQ_NORESEND, IRQ_START_FORCE))
73 desc->istate | 74 desc->istate |= IRQS_PENDING;
74 } 75 }
75 raw_spin_unlock_irq(&desc->loc 76 raw_spin_unlock_irq(&desc->lock);
76 } 77 }
77 78
78 /* 79 /*
79 * Wait for spurious interrupts to tri 80 * Wait for spurious interrupts to trigger
80 */ 81 */
81 msleep(100); 82 msleep(100);
82 83
83 /* 84 /*
84 * Now filter out any obviously spurio 85 * Now filter out any obviously spurious interrupts
85 */ 86 */
86 for_each_irq_desc(i, desc) { 87 for_each_irq_desc(i, desc) {
87 raw_spin_lock_irq(&desc->lock) 88 raw_spin_lock_irq(&desc->lock);
88 89
89 if (desc->istate & IRQS_AUTODE 90 if (desc->istate & IRQS_AUTODETECT) {
90 /* It triggered alread 91 /* It triggered already - consider it spurious. */
91 if (!(desc->istate & I 92 if (!(desc->istate & IRQS_WAITING)) {
92 desc->istate & 93 desc->istate &= ~IRQS_AUTODETECT;
93 irq_shutdown_a !! 94 irq_shutdown(desc);
94 } else 95 } else
95 if (i < 32) 96 if (i < 32)
96 mask | 97 mask |= 1 << i;
97 } 98 }
98 raw_spin_unlock_irq(&desc->loc 99 raw_spin_unlock_irq(&desc->lock);
99 } 100 }
100 101
101 return mask; 102 return mask;
102 } 103 }
103 EXPORT_SYMBOL(probe_irq_on); 104 EXPORT_SYMBOL(probe_irq_on);
104 105
105 /** 106 /**
106 * probe_irq_mask - scan a bitmap of inte 107 * probe_irq_mask - scan a bitmap of interrupt lines
107 * @val: mask of interrupts to consider 108 * @val: mask of interrupts to consider
108 * 109 *
109 * Scan the interrupt lines and return a 110 * Scan the interrupt lines and return a bitmap of active
110 * autodetect interrupts. The interrupt p 111 * autodetect interrupts. The interrupt probe logic state
111 * is then returned to its previous value 112 * is then returned to its previous value.
112 * 113 *
113 * Note: we need to scan all the irq's ev 114 * Note: we need to scan all the irq's even though we will
114 * only return autodetect irq numbers - j 115 * only return autodetect irq numbers - just so that we reset
115 * them all to a known state. 116 * them all to a known state.
116 */ 117 */
117 unsigned int probe_irq_mask(unsigned long val) 118 unsigned int probe_irq_mask(unsigned long val)
118 { 119 {
119 unsigned int mask = 0; 120 unsigned int mask = 0;
120 struct irq_desc *desc; 121 struct irq_desc *desc;
121 int i; 122 int i;
122 123
123 for_each_irq_desc(i, desc) { 124 for_each_irq_desc(i, desc) {
124 raw_spin_lock_irq(&desc->lock) 125 raw_spin_lock_irq(&desc->lock);
125 if (desc->istate & IRQS_AUTODE 126 if (desc->istate & IRQS_AUTODETECT) {
126 if (i < 16 && !(desc-> 127 if (i < 16 && !(desc->istate & IRQS_WAITING))
127 mask |= 1 << i 128 mask |= 1 << i;
128 129
129 desc->istate &= ~IRQS_ 130 desc->istate &= ~IRQS_AUTODETECT;
130 irq_shutdown_and_deact !! 131 irq_shutdown(desc);
131 } 132 }
132 raw_spin_unlock_irq(&desc->loc 133 raw_spin_unlock_irq(&desc->lock);
133 } 134 }
134 mutex_unlock(&probing_active); 135 mutex_unlock(&probing_active);
135 136
136 return mask & val; 137 return mask & val;
137 } 138 }
138 EXPORT_SYMBOL(probe_irq_mask); 139 EXPORT_SYMBOL(probe_irq_mask);
139 140
140 /** 141 /**
141 * probe_irq_off - end an interrupt aut 142 * probe_irq_off - end an interrupt autodetect
142 * @val: mask of potential interrupts (un 143 * @val: mask of potential interrupts (unused)
143 * 144 *
144 * Scans the unused interrupt lines and r 145 * Scans the unused interrupt lines and returns the line which
145 * appears to have triggered the interrup 146 * appears to have triggered the interrupt. If no interrupt was
146 * found then zero is returned. If more t 147 * found then zero is returned. If more than one interrupt is
147 * found then minus the first candidate i 148 * found then minus the first candidate is returned to indicate
148 * their is doubt. 149 * their is doubt.
149 * 150 *
150 * The interrupt probe logic state is ret 151 * The interrupt probe logic state is returned to its previous
151 * value. 152 * value.
152 * 153 *
153 * BUGS: When used in a module (which arg 154 * BUGS: When used in a module (which arguably shouldn't happen)
154 * nothing prevents two IRQ probe callers 155 * nothing prevents two IRQ probe callers from overlapping. The
155 * results of this are non-optimal. 156 * results of this are non-optimal.
156 */ 157 */
157 int probe_irq_off(unsigned long val) 158 int probe_irq_off(unsigned long val)
158 { 159 {
159 int i, irq_found = 0, nr_of_irqs = 0; 160 int i, irq_found = 0, nr_of_irqs = 0;
160 struct irq_desc *desc; 161 struct irq_desc *desc;
161 162
162 for_each_irq_desc(i, desc) { 163 for_each_irq_desc(i, desc) {
163 raw_spin_lock_irq(&desc->lock) 164 raw_spin_lock_irq(&desc->lock);
164 165
165 if (desc->istate & IRQS_AUTODE 166 if (desc->istate & IRQS_AUTODETECT) {
166 if (!(desc->istate & I 167 if (!(desc->istate & IRQS_WAITING)) {
167 if (!nr_of_irq 168 if (!nr_of_irqs)
168 irq_fo 169 irq_found = i;
169 nr_of_irqs++; 170 nr_of_irqs++;
170 } 171 }
171 desc->istate &= ~IRQS_ 172 desc->istate &= ~IRQS_AUTODETECT;
172 irq_shutdown_and_deact !! 173 irq_shutdown(desc);
173 } 174 }
174 raw_spin_unlock_irq(&desc->loc 175 raw_spin_unlock_irq(&desc->lock);
175 } 176 }
176 mutex_unlock(&probing_active); 177 mutex_unlock(&probing_active);
177 178
178 if (nr_of_irqs > 1) 179 if (nr_of_irqs > 1)
179 irq_found = -irq_found; 180 irq_found = -irq_found;
180 181
181 return irq_found; 182 return irq_found;
182 } 183 }
183 EXPORT_SYMBOL(probe_irq_off); 184 EXPORT_SYMBOL(probe_irq_off);
184 185
185 186
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