1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * |
4 | * Copyright (C) 2012 ARM Limited |
5 | */ |
6 | |
7 | #include <linux/delay.h> |
8 | #include <linux/notifier.h> |
9 | #include <linux/of.h> |
10 | #include <linux/platform_device.h> |
11 | #include <linux/property.h> |
12 | #include <linux/reboot.h> |
13 | #include <linux/stat.h> |
14 | #include <linux/vexpress.h> |
15 | |
16 | static 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(map: reg, reg: 0, val: 0); |
23 | if (!err) |
24 | mdelay(1000); |
25 | } |
26 | |
27 | dev_emerg(dev, "Unable to %s (%d)\n" , what, err); |
28 | } |
29 | |
30 | static struct device *vexpress_power_off_device; |
31 | static atomic_t vexpress_restart_nb_refcnt = ATOMIC_INIT(0); |
32 | |
33 | static void vexpress_power_off(void) |
34 | { |
35 | vexpress_reset_do(dev: vexpress_power_off_device, what: "power off" ); |
36 | } |
37 | |
38 | static struct device *vexpress_restart_device; |
39 | |
40 | static int vexpress_restart(struct notifier_block *this, unsigned long mode, |
41 | void *cmd) |
42 | { |
43 | vexpress_reset_do(dev: vexpress_restart_device, what: "restart" ); |
44 | |
45 | return NOTIFY_DONE; |
46 | } |
47 | |
48 | static struct notifier_block vexpress_restart_nb = { |
49 | .notifier_call = vexpress_restart, |
50 | .priority = 128, |
51 | }; |
52 | |
53 | static ssize_t vexpress_reset_active_show(struct device *dev, |
54 | struct device_attribute *attr, char *buf) |
55 | { |
56 | return sprintf(buf, fmt: "%d\n" , vexpress_restart_device == dev); |
57 | } |
58 | |
59 | static 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(s: buf, base: 0, res: &value); |
64 | |
65 | if (!err && value) |
66 | vexpress_restart_device = dev; |
67 | |
68 | return err ? err : count; |
69 | } |
70 | |
71 | static DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show, |
72 | vexpress_reset_active_store); |
73 | |
74 | |
75 | enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT }; |
76 | |
77 | static 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 | |
91 | static int _vexpress_register_restart_handler(struct device *dev) |
92 | { |
93 | int err; |
94 | |
95 | vexpress_restart_device = dev; |
96 | if (atomic_inc_return(v: &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(v: &vexpress_restart_nb_refcnt); |
101 | return err; |
102 | } |
103 | } |
104 | device_create_file(device: dev, entry: &dev_attr_active); |
105 | |
106 | return 0; |
107 | } |
108 | |
109 | static int vexpress_reset_probe(struct platform_device *pdev) |
110 | { |
111 | enum vexpress_reset_func func; |
112 | struct regmap *regmap; |
113 | int ret = 0; |
114 | |
115 | regmap = devm_regmap_init_vexpress_config(dev: &pdev->dev); |
116 | if (IS_ERR(ptr: regmap)) |
117 | return PTR_ERR(ptr: regmap); |
118 | dev_set_drvdata(dev: &pdev->dev, data: regmap); |
119 | |
120 | func = (uintptr_t)device_get_match_data(dev: &pdev->dev); |
121 | switch (func) { |
122 | case FUNC_SHUTDOWN: |
123 | vexpress_power_off_device = &pdev->dev; |
124 | pm_power_off = vexpress_power_off; |
125 | break; |
126 | case FUNC_RESET: |
127 | if (!vexpress_restart_device) |
128 | ret = _vexpress_register_restart_handler(dev: &pdev->dev); |
129 | break; |
130 | case FUNC_REBOOT: |
131 | ret = _vexpress_register_restart_handler(dev: &pdev->dev); |
132 | break; |
133 | } |
134 | |
135 | return ret; |
136 | } |
137 | |
138 | static struct platform_driver vexpress_reset_driver = { |
139 | .probe = vexpress_reset_probe, |
140 | .driver = { |
141 | .name = "vexpress-reset" , |
142 | .of_match_table = vexpress_reset_of_match, |
143 | .suppress_bind_attrs = true, |
144 | }, |
145 | }; |
146 | builtin_platform_driver(vexpress_reset_driver); |
147 | |