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/jiffies.h>
15 #include <linux/of.h>
16 #include <linux/of_device.h>
17 #include <linux/platform_device.h>
18 #include <linux/stat.h>
19 #include <linux/vexpress.h>
20 
21 static void vexpress_reset_do(struct device *dev, const char *what)
22 {
23 	int err = -ENOENT;
24 	struct vexpress_config_func *func =
25 			vexpress_config_func_get_by_dev(dev);
26 
27 	if (func) {
28 		unsigned long timeout;
29 
30 		err = vexpress_config_write(func, 0, 0);
31 
32 		timeout = jiffies + HZ;
33 		while (time_before(jiffies, timeout))
34 			cpu_relax();
35 	}
36 
37 	dev_emerg(dev, "Unable to %s (%d)\n", what, err);
38 }
39 
40 static struct device *vexpress_power_off_device;
41 
42 void vexpress_power_off(void)
43 {
44 	vexpress_reset_do(vexpress_power_off_device, "power off");
45 }
46 
47 static struct device *vexpress_restart_device;
48 
49 void vexpress_restart(char str, const char *cmd)
50 {
51 	vexpress_reset_do(vexpress_restart_device, "restart");
52 }
53 
54 static ssize_t vexpress_reset_active_show(struct device *dev,
55 		struct device_attribute *attr, char *buf)
56 {
57 	return sprintf(buf, "%d\n", vexpress_restart_device == dev);
58 }
59 
60 static ssize_t vexpress_reset_active_store(struct device *dev,
61 		struct device_attribute *attr, const char *buf, size_t count)
62 {
63 	long value;
64 	int err = kstrtol(buf, 0, &value);
65 
66 	if (!err && value)
67 		vexpress_restart_device = dev;
68 
69 	return err ? err : count;
70 }
71 
72 DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,
73 		vexpress_reset_active_store);
74 
75 
76 enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };
77 
78 static struct of_device_id vexpress_reset_of_match[] = {
79 	{
80 		.compatible = "arm,vexpress-reset",
81 		.data = (void *)FUNC_RESET,
82 	}, {
83 		.compatible = "arm,vexpress-shutdown",
84 		.data = (void *)FUNC_SHUTDOWN
85 	}, {
86 		.compatible = "arm,vexpress-reboot",
87 		.data = (void *)FUNC_REBOOT
88 	},
89 	{}
90 };
91 
92 static int vexpress_reset_probe(struct platform_device *pdev)
93 {
94 	enum vexpress_reset_func func;
95 	const struct of_device_id *match =
96 			of_match_device(vexpress_reset_of_match, &pdev->dev);
97 
98 	if (match)
99 		func = (enum vexpress_reset_func)match->data;
100 	else
101 		func = pdev->id_entry->driver_data;
102 
103 	switch (func) {
104 	case FUNC_SHUTDOWN:
105 		vexpress_power_off_device = &pdev->dev;
106 		break;
107 	case FUNC_RESET:
108 		if (!vexpress_restart_device)
109 			vexpress_restart_device = &pdev->dev;
110 		device_create_file(&pdev->dev, &dev_attr_active);
111 		break;
112 	case FUNC_REBOOT:
113 		vexpress_restart_device = &pdev->dev;
114 		device_create_file(&pdev->dev, &dev_attr_active);
115 		break;
116 	};
117 
118 	return 0;
119 }
120 
121 static const struct platform_device_id vexpress_reset_id_table[] = {
122 	{ .name = "vexpress-reset", .driver_data = FUNC_RESET, },
123 	{ .name = "vexpress-shutdown", .driver_data = FUNC_SHUTDOWN, },
124 	{ .name = "vexpress-reboot", .driver_data = FUNC_REBOOT, },
125 	{}
126 };
127 
128 static struct platform_driver vexpress_reset_driver = {
129 	.probe = vexpress_reset_probe,
130 	.driver = {
131 		.name = "vexpress-reset",
132 		.of_match_table = vexpress_reset_of_match,
133 	},
134 	.id_table = vexpress_reset_id_table,
135 };
136 
137 static int __init vexpress_reset_init(void)
138 {
139 	return platform_driver_register(&vexpress_reset_driver);
140 }
141 device_initcall(vexpress_reset_init);
142