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7#include <linux/delay.h>
8#include <linux/notifier.h>
9#include <linux/of.h>
10#include <linux/of_device.h>
11#include <linux/platform_device.h>
12#include <linux/reboot.h>
13#include <linux/stat.h>
14#include <linux/vexpress.h>
15
16static void vexpress_reset_do(struct device *dev, const char *what)
17{
18 int err = -ENOENT;
19 struct regmap *reg = dev_get_drvdata(dev);
20
21 if (reg) {
22 err = regmap_write(reg, 0, 0);
23 if (!err)
24 mdelay(1000);
25 }
26
27 dev_emerg(dev, "Unable to %s (%d)\n", what, err);
28}
29
30static struct device *vexpress_power_off_device;
31static atomic_t vexpress_restart_nb_refcnt = ATOMIC_INIT(0);
32
33static void vexpress_power_off(void)
34{
35 vexpress_reset_do(vexpress_power_off_device, "power off");
36}
37
38static struct device *vexpress_restart_device;
39
40static int vexpress_restart(struct notifier_block *this, unsigned long mode,
41 void *cmd)
42{
43 vexpress_reset_do(vexpress_restart_device, "restart");
44
45 return NOTIFY_DONE;
46}
47
48static struct notifier_block vexpress_restart_nb = {
49 .notifier_call = vexpress_restart,
50 .priority = 128,
51};
52
53static ssize_t vexpress_reset_active_show(struct device *dev,
54 struct device_attribute *attr, char *buf)
55{
56 return sprintf(buf, "%d\n", vexpress_restart_device == dev);
57}
58
59static ssize_t vexpress_reset_active_store(struct device *dev,
60 struct device_attribute *attr, const char *buf, size_t count)
61{
62 long value;
63 int err = kstrtol(buf, 0, &value);
64
65 if (!err && value)
66 vexpress_restart_device = dev;
67
68 return err ? err : count;
69}
70
71static DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,
72 vexpress_reset_active_store);
73
74
75enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };
76
77static const struct of_device_id vexpress_reset_of_match[] = {
78 {
79 .compatible = "arm,vexpress-reset",
80 .data = (void *)FUNC_RESET,
81 }, {
82 .compatible = "arm,vexpress-shutdown",
83 .data = (void *)FUNC_SHUTDOWN
84 }, {
85 .compatible = "arm,vexpress-reboot",
86 .data = (void *)FUNC_REBOOT
87 },
88 {}
89};
90
91static int _vexpress_register_restart_handler(struct device *dev)
92{
93 int err;
94
95 vexpress_restart_device = dev;
96 if (atomic_inc_return(&vexpress_restart_nb_refcnt) == 1) {
97 err = register_restart_handler(&vexpress_restart_nb);
98 if (err) {
99 dev_err(dev, "cannot register restart handler (err=%d)\n", err);
100 atomic_dec(&vexpress_restart_nb_refcnt);
101 return err;
102 }
103 }
104 device_create_file(dev, &dev_attr_active);
105
106 return 0;
107}
108
109static int vexpress_reset_probe(struct platform_device *pdev)
110{
111 const struct of_device_id *match =
112 of_match_device(vexpress_reset_of_match, &pdev->dev);
113 struct regmap *regmap;
114 int ret = 0;
115
116 if (!match)
117 return -EINVAL;
118
119 regmap = devm_regmap_init_vexpress_config(&pdev->dev);
120 if (IS_ERR(regmap))
121 return PTR_ERR(regmap);
122 dev_set_drvdata(&pdev->dev, regmap);
123
124 switch ((enum vexpress_reset_func)match->data) {
125 case FUNC_SHUTDOWN:
126 vexpress_power_off_device = &pdev->dev;
127 pm_power_off = vexpress_power_off;
128 break;
129 case FUNC_RESET:
130 if (!vexpress_restart_device)
131 ret = _vexpress_register_restart_handler(&pdev->dev);
132 break;
133 case FUNC_REBOOT:
134 ret = _vexpress_register_restart_handler(&pdev->dev);
135 break;
136 }
137
138 return ret;
139}
140
141static struct platform_driver vexpress_reset_driver = {
142 .probe = vexpress_reset_probe,
143 .driver = {
144 .name = "vexpress-reset",
145 .of_match_table = vexpress_reset_of_match,
146 .suppress_bind_attrs = true,
147 },
148};
149builtin_platform_driver(vexpress_reset_driver);
150
