aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/pika_wdt.c
blob: 435ec2aed4fe49b8eb956d94301648de350d84e2 (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
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
/*
 * PIKA FPGA based Watchdog Timer
 *
 * Copyright (c) 2008 PIKA Technologies
 *   Sean MacLennan <smaclennan@pikatech.com>
 */

#include <linux/init.h>
#include <linux/errno.h>
#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/reboot.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/of_platform.h>

#define DRV_NAME "PIKA-WDT"
#define PFX DRV_NAME ": "

/* Hardware timeout in seconds */
#define WDT_HW_TIMEOUT 2

/* Timer heartbeat (500ms) */
#define WDT_TIMEOUT	(HZ/2)

/* User land timeout */
#define WDT_HEARTBEAT 15
static int heartbeat = WDT_HEARTBEAT;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
	"(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");

static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static struct {
	void __iomem *fpga;
	unsigned long next_heartbeat;	/* the next_heartbeat for the timer */
	unsigned long open;
	char expect_close;
	int bootstatus;
	struct timer_list timer;	/* The timer that pings the watchdog */
} pikawdt_private;

static const struct watchdog_info ident = {
	.identity	= DRV_NAME,
	.options	= WDIOF_CARDRESET |
			  WDIOF_SETTIMEOUT |
			  WDIOF_KEEPALIVEPING |
			  WDIOF_MAGICCLOSE,
};

/*
 * Reload the watchdog timer.  (ie, pat the watchdog)
 */
static inline void pikawdt_reset(void)
{
	/* -- FPGA: Reset Control Register (32bit R/W) (Offset: 0x14) --
	 * Bit 7,    WTCHDG_EN: When set to 1, the watchdog timer is enabled.
	 *           Once enabled, it cannot be disabled. The watchdog can be
	 *           kicked by performing any write access to the reset
	 *           control register (this register).
	 * Bit 8-11, WTCHDG_TIMEOUT_SEC: Sets the watchdog timeout value in
	 *           seconds. Valid ranges are 1 to 15 seconds. The value can
	 *           be modified dynamically.
	 */
	unsigned reset = in_be32(pikawdt_private.fpga + 0x14);
	/* enable with max timeout - 15 seconds */
	reset |= (1 << 7) + (WDT_HW_TIMEOUT << 8);
	out_be32(pikawdt_private.fpga + 0x14, reset);
}

/*
 * Timer tick
 */
static void pikawdt_ping(unsigned long data)
{
	if (time_before(jiffies, pikawdt_private.next_heartbeat) ||
			(!nowayout && !pikawdt_private.open)) {
		pikawdt_reset();
		mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
	} else
		printk(KERN_CRIT PFX "I will reset your machine !\n");
}


static void pikawdt_keepalive(void)
{
	pikawdt_private.next_heartbeat = jiffies + heartbeat * HZ;
}

static void pikawdt_start(void)
{
	pikawdt_keepalive();
	mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
}

/*
 * Watchdog device is opened, and watchdog starts running.
 */
static int pikawdt_open(struct inode *inode, struct file *file)
{
	/* /dev/watchdog can only be opened once */
	if (test_and_set_bit(0, &pikawdt_private.open))
		return -EBUSY;

	pikawdt_start();

	return nonseekable_open(inode, file);
}

/*
 * Close the watchdog device.
 */
static int pikawdt_release(struct inode *inode, struct file *file)
{
	/* stop internal ping */
	if (!pikawdt_private.expect_close)
		del_timer(&pikawdt_private.timer);

	clear_bit(0, &pikawdt_private.open);
	pikawdt_private.expect_close = 0;
	return 0;
}

/*
 * Pat the watchdog whenever device is written to.
 */
static ssize_t pikawdt_write(struct file *file, const char __user *data,
			     size_t len, loff_t *ppos)
{
	if (!len)
		return 0;

	/* Scan for magic character */
	if (!nowayout) {
		size_t i;

		pikawdt_private.expect_close = 0;

		for (i = 0; i < len; i++) {
			char c;
			if (get_user(c, data + i))
				return -EFAULT;
			if (c == 'V') {
				pikawdt_private.expect_close = 42;
				break;
			}
		}
	}

	pikawdt_keepalive();

	return len;
}

/*
 * Handle commands from user-space.
 */
static long pikawdt_ioctl(struct file *file,
		unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int new_value;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;

	case WDIOC_GETSTATUS:
		return put_user(0, p);

	case WDIOC_GETBOOTSTATUS:
		return put_user(pikawdt_private.bootstatus, p);

	case WDIOC_KEEPALIVE:
		pikawdt_keepalive();
		return 0;

	case WDIOC_SETTIMEOUT:
		if (get_user(new_value, p))
			return -EFAULT;

		heartbeat = new_value;
		pikawdt_keepalive();

		return put_user(new_value, p);  /* return current value */

	case WDIOC_GETTIMEOUT:
		return put_user(heartbeat, p);
	}
	return -ENOTTY;
}


static const struct file_operations pikawdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.open		= pikawdt_open,
	.release	= pikawdt_release,
	.write		= pikawdt_write,
	.unlocked_ioctl	= pikawdt_ioctl,
};

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

static int __init pikawdt_init(void)
{
	struct device_node *np;
	void __iomem *fpga;
	static u32 post1;
	int ret;

	np = of_find_compatible_node(NULL, NULL, "pika,fpga");
	if (np == NULL) {
		printk(KERN_ERR PFX "Unable to find fpga.\n");
		return -ENOENT;
	}

	pikawdt_private.fpga = of_iomap(np, 0);
	of_node_put(np);
	if (pikawdt_private.fpga == NULL) {
		printk(KERN_ERR PFX "Unable to map fpga.\n");
		return -ENOMEM;
	}

	ident.firmware_version = in_be32(pikawdt_private.fpga + 0x1c) & 0xffff;

	/* POST information is in the sd area. */
	np = of_find_compatible_node(NULL, NULL, "pika,fpga-sd");
	if (np == NULL) {
		printk(KERN_ERR PFX "Unable to find fpga-sd.\n");
		ret = -ENOENT;
		goto out;
	}

	fpga = of_iomap(np, 0);
	of_node_put(np);
	if (fpga == NULL) {
		printk(KERN_ERR PFX "Unable to map fpga-sd.\n");
		ret = -ENOMEM;
		goto out;
	}

	/* -- FPGA: POST Test Results Register 1 (32bit R/W) (Offset: 0x4040) --
	 * Bit 31,   WDOG: Set to 1 when the last reset was caused by a watchdog
	 *           timeout.
	 */
	post1 = in_be32(fpga + 0x40);
	if (post1 & 0x80000000)
		pikawdt_private.bootstatus = WDIOF_CARDRESET;

	iounmap(fpga);

	setup_timer(&pikawdt_private.timer, pikawdt_ping, 0);

	ret = misc_register(&pikawdt_miscdev);
	if (ret) {
		printk(KERN_ERR PFX "Unable to register miscdev.\n");
		goto out;
	}

	printk(KERN_INFO PFX "initialized. heartbeat=%d sec (nowayout=%d)\n",
							heartbeat, nowayout);
	return 0;

out:
	iounmap(pikawdt_private.fpga);
	return ret;
}

static void __exit pikawdt_exit(void)
{
	misc_deregister(&pikawdt_miscdev);

	iounmap(pikawdt_private.fpga);
}

module_init(pikawdt_init);
module_exit(pikawdt_exit);

MODULE_AUTHOR("Sean MacLennan <smaclennan@pikatech.com>");
MODULE_DESCRIPTION("PIKA FPGA based Watchdog Timer");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);