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 #include <asm/system_misc.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 vexpress_config_func *func =
27 vexpress_config_func_get_by_dev(dev);
28
29 if (func) {
30 unsigned long timeout;
31
32 err = vexpress_config_write(func, 0, 0);
33
34 timeout = jiffies + HZ;
35 while (time_before(jiffies, timeout))
36 cpu_relax();
37 }
38
39 dev_emerg(dev, "Unable to %s (%d)\n", what, err);
40 }
41
42 static struct device *vexpress_power_off_device;
43
vexpress_power_off(void)44 static void vexpress_power_off(void)
45 {
46 vexpress_reset_do(vexpress_power_off_device, "power off");
47 }
48
49 static struct device *vexpress_restart_device;
50
vexpress_restart(char str,const char * cmd)51 static void vexpress_restart(char str, const char *cmd)
52 {
53 vexpress_reset_do(vexpress_restart_device, "restart");
54 }
55
vexpress_reset_active_show(struct device * dev,struct device_attribute * attr,char * buf)56 static ssize_t vexpress_reset_active_show(struct device *dev,
57 struct device_attribute *attr, char *buf)
58 {
59 return sprintf(buf, "%d\n", vexpress_restart_device == dev);
60 }
61
vexpress_reset_active_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)62 static ssize_t vexpress_reset_active_store(struct device *dev,
63 struct device_attribute *attr, const char *buf, size_t count)
64 {
65 long value;
66 int err = kstrtol(buf, 0, &value);
67
68 if (!err && value)
69 vexpress_restart_device = dev;
70
71 return err ? err : count;
72 }
73
74 DEVICE_ATTR(active, S_IRUGO | S_IWUSR, vexpress_reset_active_show,
75 vexpress_reset_active_store);
76
77
78 enum vexpress_reset_func { FUNC_RESET, FUNC_SHUTDOWN, FUNC_REBOOT };
79
80 static struct of_device_id vexpress_reset_of_match[] = {
81 {
82 .compatible = "arm,vexpress-reset",
83 .data = (void *)FUNC_RESET,
84 }, {
85 .compatible = "arm,vexpress-shutdown",
86 .data = (void *)FUNC_SHUTDOWN
87 }, {
88 .compatible = "arm,vexpress-reboot",
89 .data = (void *)FUNC_REBOOT
90 },
91 {}
92 };
93
vexpress_reset_probe(struct platform_device * pdev)94 static int vexpress_reset_probe(struct platform_device *pdev)
95 {
96 enum vexpress_reset_func func;
97 const struct of_device_id *match =
98 of_match_device(vexpress_reset_of_match, &pdev->dev);
99
100 if (match)
101 func = (enum vexpress_reset_func)match->data;
102 else
103 func = pdev->id_entry->driver_data;
104
105 switch (func) {
106 case FUNC_SHUTDOWN:
107 vexpress_power_off_device = &pdev->dev;
108 pm_power_off = vexpress_power_off;
109 break;
110 case FUNC_RESET:
111 if (!vexpress_restart_device)
112 vexpress_restart_device = &pdev->dev;
113 arm_pm_restart = vexpress_restart;
114 device_create_file(&pdev->dev, &dev_attr_active);
115 break;
116 case FUNC_REBOOT:
117 vexpress_restart_device = &pdev->dev;
118 arm_pm_restart = vexpress_restart;
119 device_create_file(&pdev->dev, &dev_attr_active);
120 break;
121 };
122
123 return 0;
124 }
125
126 static const struct platform_device_id vexpress_reset_id_table[] = {
127 { .name = "vexpress-reset", .driver_data = FUNC_RESET, },
128 { .name = "vexpress-shutdown", .driver_data = FUNC_SHUTDOWN, },
129 { .name = "vexpress-reboot", .driver_data = FUNC_REBOOT, },
130 {}
131 };
132
133 static struct platform_driver vexpress_reset_driver = {
134 .probe = vexpress_reset_probe,
135 .driver = {
136 .name = "vexpress-reset",
137 .of_match_table = vexpress_reset_of_match,
138 },
139 .id_table = vexpress_reset_id_table,
140 };
141
vexpress_reset_init(void)142 static int __init vexpress_reset_init(void)
143 {
144 return platform_driver_register(&vexpress_reset_driver);
145 }
146 device_initcall(vexpress_reset_init);
147