1 /*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License version 2 as
4 * published by the Free Software Foundation.
5 *
6 * This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 * GNU General Public License for more details.
10 *
11 * Copyright (C) 2012 ARM Limited
12 */
13
14 #include <linux/delay.h>
15 #include <linux/notifier.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/platform_device.h>
19 #include <linux/reboot.h>
20 #include <linux/stat.h>
21 #include <linux/vexpress.h>
22
vexpress_reset_do(struct device * dev,const char * what)23 static void vexpress_reset_do(struct device *dev, const char *what)
24 {
25 int err = -ENOENT;
26 struct regmap *reg = dev_get_drvdata(dev);
27
28 if (reg) {
29 err = regmap_write(reg, 0, 0);
30 if (!err)
31 mdelay(1000);
32 }
33
34 dev_emerg(dev, "Unable to %s (%d)\n", what, err);
35 }
36
37 static struct device *vexpress_power_off_device;
38 static atomic_t vexpress_restart_nb_refcnt = ATOMIC_INIT(0);
39
vexpress_power_off(void)40 static void vexpress_power_off(void)
41 {
42 vexpress_reset_do(vexpress_power_off_device, "power off");
43 }
44
45 static struct device *vexpress_restart_device;
46
vexpress_restart(struct notifier_block * this,unsigned long mode,void * cmd)47 static int vexpress_restart(struct notifier_block *this, unsigned long mode,
48 void *cmd)
49 {
50 vexpress_reset_do(vexpress_restart_device, "restart");
51
52 return NOTIFY_DONE;
53 }
54
55 static struct notifier_block vexpress_restart_nb = {
56 .notifier_call = vexpress_restart,
57 .priority = 128,
58 };
59
vexpress_reset_active_show(struct device * dev,struct device_attribute * attr,char * buf)60 static ssize_t vexpress_reset_active_show(struct device *dev,
61 struct device_attribute *attr, char *buf)
62 {
63 return sprintf(buf, "%d\n", vexpress_restart_device == dev);
64 }
65
vexpress_reset_active_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)66 static ssize_t vexpress_reset_active_store(struct device *dev,
67 struct device_attribute *attr, const char *buf, size_t count)
68 {
69 long value;
70 int err = kstrtol(buf, 0, &value);
71
72 if (!err && value)
73 vexpress_restart_device = dev;
74
75 return err ? err : count;
76 }
77
78 static DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,
79 vexpress_reset_active_store);
80
81
82 enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };
83
84 static const struct of_device_id vexpress_reset_of_match[] = {
85 {
86 .compatible = "arm,vexpress-reset",
87 .data = (void *)FUNC_RESET,
88 }, {
89 .compatible = "arm,vexpress-shutdown",
90 .data = (void *)FUNC_SHUTDOWN
91 }, {
92 .compatible = "arm,vexpress-reboot",
93 .data = (void *)FUNC_REBOOT
94 },
95 {}
96 };
97
_vexpress_register_restart_handler(struct device * dev)98 static int _vexpress_register_restart_handler(struct device *dev)
99 {
100 int err;
101
102 vexpress_restart_device = dev;
103 if (atomic_inc_return(&vexpress_restart_nb_refcnt) == 1) {
104 err = register_restart_handler(&vexpress_restart_nb);
105 if (err) {
106 dev_err(dev, "cannot register restart handler (err=%d)\n", err);
107 atomic_dec(&vexpress_restart_nb_refcnt);
108 return err;
109 }
110 }
111 device_create_file(dev, &dev_attr_active);
112
113 return 0;
114 }
115
vexpress_reset_probe(struct platform_device * pdev)116 static int vexpress_reset_probe(struct platform_device *pdev)
117 {
118 const struct of_device_id *match =
119 of_match_device(vexpress_reset_of_match, &pdev->dev);
120 struct regmap *regmap;
121 int ret = 0;
122
123 if (!match)
124 return -EINVAL;
125
126 regmap = devm_regmap_init_vexpress_config(&pdev->dev);
127 if (IS_ERR(regmap))
128 return PTR_ERR(regmap);
129 dev_set_drvdata(&pdev->dev, regmap);
130
131 switch ((enum vexpress_reset_func)match->data) {
132 case FUNC_SHUTDOWN:
133 vexpress_power_off_device = &pdev->dev;
134 pm_power_off = vexpress_power_off;
135 break;
136 case FUNC_RESET:
137 if (!vexpress_restart_device)
138 ret = _vexpress_register_restart_handler(&pdev->dev);
139 break;
140 case FUNC_REBOOT:
141 ret = _vexpress_register_restart_handler(&pdev->dev);
142 break;
143 };
144
145 return ret;
146 }
147
148 static struct platform_driver vexpress_reset_driver = {
149 .probe = vexpress_reset_probe,
150 .driver = {
151 .name = "vexpress-reset",
152 .of_match_table = vexpress_reset_of_match,
153 },
154 };
155
vexpress_reset_init(void)156 static int __init vexpress_reset_init(void)
157 {
158 return platform_driver_register(&vexpress_reset_driver);
159 }
160 device_initcall(vexpress_reset_init);
161
