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
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