1 /*
2  * MPIC timer wakeup driver
3  *
4  * Copyright 2013 Freescale Semiconductor, Inc.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License as published by the
8  * Free Software Foundation; either version 2 of the License, or (at your
9  * option) any later version.
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/errno.h>
15 #include <linux/module.h>
16 #include <linux/interrupt.h>
17 #include <linux/device.h>
18 
19 #include <asm/mpic_timer.h>
20 #include <asm/mpic.h>
21 
22 struct fsl_mpic_timer_wakeup {
23 	struct mpic_timer *timer;
24 	struct work_struct free_work;
25 };
26 
27 static struct fsl_mpic_timer_wakeup *fsl_wakeup;
28 static DEFINE_MUTEX(sysfs_lock);
29 
30 static void fsl_free_resource(struct work_struct *ws)
31 {
32 	struct fsl_mpic_timer_wakeup *wakeup =
33 		container_of(ws, struct fsl_mpic_timer_wakeup, free_work);
34 
35 	mutex_lock(&sysfs_lock);
36 
37 	if (wakeup->timer) {
38 		disable_irq_wake(wakeup->timer->irq);
39 		mpic_free_timer(wakeup->timer);
40 	}
41 
42 	wakeup->timer = NULL;
43 	mutex_unlock(&sysfs_lock);
44 }
45 
46 static irqreturn_t fsl_mpic_timer_irq(int irq, void *dev_id)
47 {
48 	struct fsl_mpic_timer_wakeup *wakeup = dev_id;
49 
50 	schedule_work(&wakeup->free_work);
51 
52 	return wakeup->timer ? IRQ_HANDLED : IRQ_NONE;
53 }
54 
55 static ssize_t fsl_timer_wakeup_show(struct device *dev,
56 				struct device_attribute *attr,
57 				char *buf)
58 {
59 	time64_t interval = 0;
60 
61 	mutex_lock(&sysfs_lock);
62 	if (fsl_wakeup->timer) {
63 		mpic_get_remain_time(fsl_wakeup->timer, &interval);
64 		interval++;
65 	}
66 	mutex_unlock(&sysfs_lock);
67 
68 	return sprintf(buf, "%lld\n", interval);
69 }
70 
71 static ssize_t fsl_timer_wakeup_store(struct device *dev,
72 				struct device_attribute *attr,
73 				const char *buf,
74 				size_t count)
75 {
76 	time64_t interval;
77 	int ret;
78 
79 	if (kstrtoll(buf, 0, &interval))
80 		return -EINVAL;
81 
82 	mutex_lock(&sysfs_lock);
83 
84 	if (fsl_wakeup->timer) {
85 		disable_irq_wake(fsl_wakeup->timer->irq);
86 		mpic_free_timer(fsl_wakeup->timer);
87 		fsl_wakeup->timer = NULL;
88 	}
89 
90 	if (!interval) {
91 		mutex_unlock(&sysfs_lock);
92 		return count;
93 	}
94 
95 	fsl_wakeup->timer = mpic_request_timer(fsl_mpic_timer_irq,
96 						fsl_wakeup, interval);
97 	if (!fsl_wakeup->timer) {
98 		mutex_unlock(&sysfs_lock);
99 		return -EINVAL;
100 	}
101 
102 	ret = enable_irq_wake(fsl_wakeup->timer->irq);
103 	if (ret) {
104 		mpic_free_timer(fsl_wakeup->timer);
105 		fsl_wakeup->timer = NULL;
106 		mutex_unlock(&sysfs_lock);
107 
108 		return ret;
109 	}
110 
111 	mpic_start_timer(fsl_wakeup->timer);
112 
113 	mutex_unlock(&sysfs_lock);
114 
115 	return count;
116 }
117 
118 static struct device_attribute mpic_attributes = __ATTR(timer_wakeup, 0644,
119 			fsl_timer_wakeup_show, fsl_timer_wakeup_store);
120 
121 static int __init fsl_wakeup_sys_init(void)
122 {
123 	int ret;
124 
125 	fsl_wakeup = kzalloc(sizeof(struct fsl_mpic_timer_wakeup), GFP_KERNEL);
126 	if (!fsl_wakeup)
127 		return -ENOMEM;
128 
129 	INIT_WORK(&fsl_wakeup->free_work, fsl_free_resource);
130 
131 	ret = device_create_file(mpic_subsys.dev_root, &mpic_attributes);
132 	if (ret)
133 		kfree(fsl_wakeup);
134 
135 	return ret;
136 }
137 
138 static void __exit fsl_wakeup_sys_exit(void)
139 {
140 	device_remove_file(mpic_subsys.dev_root, &mpic_attributes);
141 
142 	mutex_lock(&sysfs_lock);
143 
144 	if (fsl_wakeup->timer) {
145 		disable_irq_wake(fsl_wakeup->timer->irq);
146 		mpic_free_timer(fsl_wakeup->timer);
147 	}
148 
149 	kfree(fsl_wakeup);
150 
151 	mutex_unlock(&sysfs_lock);
152 }
153 
154 module_init(fsl_wakeup_sys_init);
155 module_exit(fsl_wakeup_sys_exit);
156 
157 MODULE_DESCRIPTION("Freescale MPIC global timer wakeup driver");
158 MODULE_LICENSE("GPL v2");
159 MODULE_AUTHOR("Wang Dongsheng <dongsheng.wang@freescale.com>");
160