aboutsummaryrefslogtreecommitdiff
path: root/drivers/watchdog/orion5x_wdt.c
blob: 144776314989a1378602c2f4d6c3b65f6f38d3b6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
/*
 * drivers/watchdog/orion5x_wdt.c
 *
 * Watchdog driver for Orion5x processors
 *
 * Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
 *
 * This file is licensed under  the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/uaccess.h>
#include <linux/io.h>

/*
 * Watchdog timer block registers.
 */
#define TIMER_CTRL		(TIMER_VIRT_BASE + 0x0000)
#define  WDT_EN			0x0010
#define WDT_VAL			(TIMER_VIRT_BASE + 0x0024)

#define WDT_MAX_DURATION	(0xffffffff / ORION5X_TCLK)
#define WDT_IN_USE		0
#define WDT_OK_TO_CLOSE		1

static int nowayout = WATCHDOG_NOWAYOUT;
static int heartbeat =  WDT_MAX_DURATION;	/* (seconds) */
static unsigned long wdt_status;

static void wdt_enable(void)
{
	u32 reg;

	/* Set watchdog duration */
	writel(ORION5X_TCLK * heartbeat, WDT_VAL);

	/* Clear watchdog timer interrupt */
	reg = readl(BRIDGE_CAUSE);
	reg &= ~WDT_INT_REQ;
	writel(reg, BRIDGE_CAUSE);

	/* Enable watchdog timer */
	reg = readl(TIMER_CTRL);
	reg |= WDT_EN;
	writel(reg, TIMER_CTRL);

	/* Enable reset on watchdog */
	reg = readl(CPU_RESET_MASK);
	reg |= WDT_RESET;
	writel(reg, CPU_RESET_MASK);
}

static void wdt_disable(void)
{
	u32 reg;

	/* Disable reset on watchdog */
	reg = readl(CPU_RESET_MASK);
	reg &= ~WDT_RESET;
	writel(reg, CPU_RESET_MASK);

	/* Disable watchdog timer */
	reg = readl(TIMER_CTRL);
	reg &= ~WDT_EN;
	writel(reg, TIMER_CTRL);
}

static int orion5x_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
		return -EBUSY;
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	wdt_enable();
	return nonseekable_open(inode, file);
}

static int orion5x_wdt_get_timeleft(int *time_left)
{
	*time_left = readl(WDT_VAL) / ORION5X_TCLK;
	return 0;
}

static ssize_t orion5x_wdt_write(struct file *file, const char *data,
					size_t len, loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
			for (i = 0; i != len; i++) {
				char c;

				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					set_bit(WDT_OK_TO_CLOSE, &wdt_status);
			}
		}
		wdt_enable();
	}
	return len;
}

static struct watchdog_info ident = {
	.options	= WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
			  WDIOF_KEEPALIVEPING,
	.identity	= "Orion5x Watchdog",
};


static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
				unsigned long arg)
{
	int ret = -ENOTTY;
	int time;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		ret = copy_to_user((struct watchdog_info *)arg, &ident,
				   sizeof(ident)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		ret = put_user(0, (int *)arg);
		break;

	case WDIOC_KEEPALIVE:
		wdt_enable();
		ret = 0;
		break;

	case WDIOC_SETTIMEOUT:
		ret = get_user(time, (int *)arg);
		if (ret)
			break;

		if (time <= 0 || time > WDT_MAX_DURATION) {
			ret = -EINVAL;
			break;
		}
		heartbeat = time;
		wdt_enable();
		/* Fall through */

	case WDIOC_GETTIMEOUT:
		ret = put_user(heartbeat, (int *)arg);
		break;

	case WDIOC_GETTIMELEFT:
		if (orion5x_wdt_get_timeleft(&time)) {
			ret = -EINVAL;
			break;
		}
		ret = put_user(time, (int *)arg);
		break;
	}
	return ret;
}

static int orion5x_wdt_release(struct inode *inode, struct file *file)
{
	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
		wdt_disable();
	else
		printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
					"timer will not stop\n");
	clear_bit(WDT_IN_USE, &wdt_status);
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

	return 0;
}


static const struct file_operations orion5x_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= orion5x_wdt_write,
	.unlocked_ioctl	= orion5x_wdt_ioctl,
	.open		= orion5x_wdt_open,
	.release	= orion5x_wdt_release,
};

static struct miscdevice orion5x_wdt_miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &orion5x_wdt_fops,
};

static int __init orion5x_wdt_init(void)
{
	int ret;

	ret = misc_register(&orion5x_wdt_miscdev);
	if (ret == 0)
		printk("Orion5x Watchdog Timer: heartbeat %d sec\n",
								heartbeat);

	return ret;
}

static void __exit orion5x_wdt_exit(void)
{
	misc_deregister(&orion5x_wdt_miscdev);
}

module_init(orion5x_wdt_init);
module_exit(orion5x_wdt_exit);

MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
MODULE_DESCRIPTION("Orion5x Processor Watchdog");

module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default is "
					__MODULE_STRING(WDT_MAX_DURATION) ")");

module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");

MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);