xref: /openbmc/linux/kernel/irq/pm.c (revision 565d76cb)
1 /*
2  * linux/kernel/irq/pm.c
3  *
4  * Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
5  *
6  * This file contains power management functions related to interrupts.
7  */
8 
9 #include <linux/irq.h>
10 #include <linux/module.h>
11 #include <linux/interrupt.h>
12 
13 #include "internals.h"
14 
15 /**
16  * suspend_device_irqs - disable all currently enabled interrupt lines
17  *
18  * During system-wide suspend or hibernation device drivers need to be prevented
19  * from receiving interrupts and this function is provided for this purpose.
20  * It marks all interrupt lines in use, except for the timer ones, as disabled
21  * and sets the IRQS_SUSPENDED flag for each of them.
22  */
23 void suspend_device_irqs(void)
24 {
25 	struct irq_desc *desc;
26 	int irq;
27 
28 	for_each_irq_desc(irq, desc) {
29 		unsigned long flags;
30 
31 		raw_spin_lock_irqsave(&desc->lock, flags);
32 		__disable_irq(desc, irq, true);
33 		raw_spin_unlock_irqrestore(&desc->lock, flags);
34 	}
35 
36 	for_each_irq_desc(irq, desc)
37 		if (desc->istate & IRQS_SUSPENDED)
38 			synchronize_irq(irq);
39 }
40 EXPORT_SYMBOL_GPL(suspend_device_irqs);
41 
42 /**
43  * resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
44  *
45  * Enable all interrupt lines previously disabled by suspend_device_irqs() that
46  * have the IRQS_SUSPENDED flag set.
47  */
48 void resume_device_irqs(void)
49 {
50 	struct irq_desc *desc;
51 	int irq;
52 
53 	for_each_irq_desc(irq, desc) {
54 		unsigned long flags;
55 
56 		raw_spin_lock_irqsave(&desc->lock, flags);
57 		__enable_irq(desc, irq, true);
58 		raw_spin_unlock_irqrestore(&desc->lock, flags);
59 	}
60 }
61 EXPORT_SYMBOL_GPL(resume_device_irqs);
62 
63 /**
64  * check_wakeup_irqs - check if any wake-up interrupts are pending
65  */
66 int check_wakeup_irqs(void)
67 {
68 	struct irq_desc *desc;
69 	int irq;
70 
71 	for_each_irq_desc(irq, desc) {
72 		if (irqd_is_wakeup_set(&desc->irq_data)) {
73 			if (desc->istate & IRQS_PENDING)
74 				return -EBUSY;
75 			continue;
76 		}
77 		/*
78 		 * Check the non wakeup interrupts whether they need
79 		 * to be masked before finally going into suspend
80 		 * state. That's for hardware which has no wakeup
81 		 * source configuration facility. The chip
82 		 * implementation indicates that with
83 		 * IRQCHIP_MASK_ON_SUSPEND.
84 		 */
85 		if (desc->istate & IRQS_SUSPENDED &&
86 		    irq_desc_get_chip(desc)->flags & IRQCHIP_MASK_ON_SUSPEND)
87 			mask_irq(desc);
88 	}
89 
90 	return 0;
91 }
92