1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * MPIC timer wakeup driver
4  *
5  * Copyright 2013 Freescale Semiconductor, Inc.
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/slab.h>
10 #include <linux/errno.h>
11 #include <linux/module.h>
12 #include <linux/interrupt.h>
13 #include <linux/device.h>
14 
15 #include <asm/mpic_timer.h>
16 #include <asm/mpic.h>
17 
18 struct fsl_mpic_timer_wakeup {
19 	struct mpic_timer *timer;
20 	struct work_struct free_work;
21 };
22 
23 static struct fsl_mpic_timer_wakeup *fsl_wakeup;
24 static DEFINE_MUTEX(sysfs_lock);
25 
26 static void fsl_free_resource(struct work_struct *ws)
27 {
28 	struct fsl_mpic_timer_wakeup *wakeup =
29 		container_of(ws, struct fsl_mpic_timer_wakeup, free_work);
30 
31 	mutex_lock(&sysfs_lock);
32 
33 	if (wakeup->timer) {
34 		disable_irq_wake(wakeup->timer->irq);
35 		mpic_free_timer(wakeup->timer);
36 	}
37 
38 	wakeup->timer = NULL;
39 	mutex_unlock(&sysfs_lock);
40 }
41 
42 static irqreturn_t fsl_mpic_timer_irq(int irq, void *dev_id)
43 {
44 	struct fsl_mpic_timer_wakeup *wakeup = dev_id;
45 
46 	schedule_work(&wakeup->free_work);
47 
48 	return wakeup->timer ? IRQ_HANDLED : IRQ_NONE;
49 }
50 
51 static ssize_t fsl_timer_wakeup_show(struct device *dev,
52 				struct device_attribute *attr,
53 				char *buf)
54 {
55 	time64_t interval = 0;
56 
57 	mutex_lock(&sysfs_lock);
58 	if (fsl_wakeup->timer) {
59 		mpic_get_remain_time(fsl_wakeup->timer, &interval);
60 		interval++;
61 	}
62 	mutex_unlock(&sysfs_lock);
63 
64 	return sprintf(buf, "%lld\n", interval);
65 }
66 
67 static ssize_t fsl_timer_wakeup_store(struct device *dev,
68 				struct device_attribute *attr,
69 				const char *buf,
70 				size_t count)
71 {
72 	time64_t interval;
73 	int ret;
74 
75 	if (kstrtoll(buf, 0, &interval))
76 		return -EINVAL;
77 
78 	mutex_lock(&sysfs_lock);
79 
80 	if (fsl_wakeup->timer) {
81 		disable_irq_wake(fsl_wakeup->timer->irq);
82 		mpic_free_timer(fsl_wakeup->timer);
83 		fsl_wakeup->timer = NULL;
84 	}
85 
86 	if (!interval) {
87 		mutex_unlock(&sysfs_lock);
88 		return count;
89 	}
90 
91 	fsl_wakeup->timer = mpic_request_timer(fsl_mpic_timer_irq,
92 						fsl_wakeup, interval);
93 	if (!fsl_wakeup->timer) {
94 		mutex_unlock(&sysfs_lock);
95 		return -EINVAL;
96 	}
97 
98 	ret = enable_irq_wake(fsl_wakeup->timer->irq);
99 	if (ret) {
100 		mpic_free_timer(fsl_wakeup->timer);
101 		fsl_wakeup->timer = NULL;
102 		mutex_unlock(&sysfs_lock);
103 
104 		return ret;
105 	}
106 
107 	mpic_start_timer(fsl_wakeup->timer);
108 
109 	mutex_unlock(&sysfs_lock);
110 
111 	return count;
112 }
113 
114 static struct device_attribute mpic_attributes = __ATTR(timer_wakeup, 0644,
115 			fsl_timer_wakeup_show, fsl_timer_wakeup_store);
116 
117 static int __init fsl_wakeup_sys_init(void)
118 {
119 	struct device *dev_root;
120 	int ret = -EINVAL;
121 
122 	fsl_wakeup = kzalloc(sizeof(struct fsl_mpic_timer_wakeup), GFP_KERNEL);
123 	if (!fsl_wakeup)
124 		return -ENOMEM;
125 
126 	INIT_WORK(&fsl_wakeup->free_work, fsl_free_resource);
127 
128 	dev_root = bus_get_dev_root(&mpic_subsys);
129 	if (dev_root) {
130 		ret = device_create_file(dev_root, &mpic_attributes);
131 		put_device(dev_root);
132 		if (ret)
133 			kfree(fsl_wakeup);
134 	}
135 
136 	return ret;
137 }
138 
139 static void __exit fsl_wakeup_sys_exit(void)
140 {
141 	struct device *dev_root;
142 
143 	dev_root = bus_get_dev_root(&mpic_subsys);
144 	if (dev_root) {
145 		device_remove_file(dev_root, &mpic_attributes);
146 		put_device(dev_root);
147 	}
148 
149 	mutex_lock(&sysfs_lock);
150 
151 	if (fsl_wakeup->timer) {
152 		disable_irq_wake(fsl_wakeup->timer->irq);
153 		mpic_free_timer(fsl_wakeup->timer);
154 	}
155 
156 	kfree(fsl_wakeup);
157 
158 	mutex_unlock(&sysfs_lock);
159 }
160 
161 module_init(fsl_wakeup_sys_init);
162 module_exit(fsl_wakeup_sys_exit);
163 
164 MODULE_DESCRIPTION("Freescale MPIC global timer wakeup driver");
165 MODULE_LICENSE("GPL v2");
166 MODULE_AUTHOR("Wang Dongsheng <dongsheng.wang@freescale.com>");
167