aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/rc32434_wdt.c
blob: f78bc008cbb71b5695b00b5e6c4edec4509f2175 (plain) (blame)
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
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
/*
 *  IDT Interprise 79RC32434 watchdog driver
 *
 *  Copyright (C) 2006, Ondrej Zajicek <santiago@crfreenet.org>
 *  Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
 *
 *  based on
 *  SoftDog 0.05:	A Software Watchdog Device
 *
 *  (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
 *					All Rights Reserved.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>		/* For module specific items */
#include <linux/moduleparam.h>		/* For new moduleparam's */
#include <linux/types.h>		/* For standard types (like size_t) */
#include <linux/errno.h>		/* For the -ENODEV/... values */
#include <linux/kernel.h>		/* For printk/panic/... */
#include <linux/fs.h>			/* For file operations */
#include <linux/miscdevice.h>		/* For MODULE_ALIAS_MISCDEV
							(WATCHDOG_MINOR) */
#include <linux/watchdog.h>		/* For the watchdog specific items */
#include <linux/init.h>			/* For __init/__exit/... */
#include <linux/platform_device.h>	/* For platform_driver framework */
#include <linux/spinlock.h>		/* For spin_lock/spin_unlock/... */
#include <linux/uaccess.h>		/* For copy_to_user/put_user/... */

#include <asm/mach-rc32434/integ.h>	/* For the Watchdog registers */

#define VERSION "1.0"

static struct {
	unsigned long inuse;
	spinlock_t io_lock;
} rc32434_wdt_device;

static struct integ __iomem *wdt_reg;

static int expect_close;

/* Board internal clock speed in Hz,
 * the watchdog timer ticks at. */
extern unsigned int idt_cpu_freq;

/* translate wtcompare value to seconds and vice versa */
#define WTCOMP2SEC(x)	(x / idt_cpu_freq)
#define SEC2WTCOMP(x)	(x * idt_cpu_freq)

/* Use a default timeout of 20s. This should be
 * safe for CPU clock speeds up to 400MHz, as
 * ((2 ^ 32) - 1) / (400MHz / 2) = 21s.  */
#define WATCHDOG_TIMEOUT 20

static int timeout = WATCHDOG_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout value, in seconds (default="
		__MODULE_STRING(WATCHDOG_TIMEOUT) ")");

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

/* apply or and nand masks to data read from addr and write back */
#define SET_BITS(addr, or, nand) \
	writel((readl(&addr) | or) & ~nand, &addr)

static int rc32434_wdt_set(int new_timeout)
{
	int max_to = WTCOMP2SEC((u32)-1);

	if (new_timeout < 0 || new_timeout > max_to) {
		pr_err("timeout value must be between 0 and %d\n", max_to);
		return -EINVAL;
	}
	timeout = new_timeout;
	spin_lock(&rc32434_wdt_device.io_lock);
	writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare);
	spin_unlock(&rc32434_wdt_device.io_lock);

	return 0;
}

static void rc32434_wdt_start(void)
{
	u32 or, nand;

	spin_lock(&rc32434_wdt_device.io_lock);

	/* zero the counter before enabling */
	writel(0, &wdt_reg->wtcount);

	/* don't generate a non-maskable interrupt,
	 * do a warm reset instead */
	nand = 1 << RC32434_ERR_WNE;
	or = 1 << RC32434_ERR_WRE;

	/* reset the ERRCS timeout bit in case it's set */
	nand |= 1 << RC32434_ERR_WTO;

	SET_BITS(wdt_reg->errcs, or, nand);

	/* set the timeout (either default or based on module param) */
	rc32434_wdt_set(timeout);

	/* reset WTC timeout bit and enable WDT */
	nand = 1 << RC32434_WTC_TO;
	or = 1 << RC32434_WTC_EN;

	SET_BITS(wdt_reg->wtc, or, nand);

	spin_unlock(&rc32434_wdt_device.io_lock);
	pr_info("Started watchdog timer\n");
}

static void rc32434_wdt_stop(void)
{
	spin_lock(&rc32434_wdt_device.io_lock);

	/* Disable WDT */
	SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN);

	spin_unlock(&rc32434_wdt_device.io_lock);
	pr_info("Stopped watchdog timer\n");
}

static void rc32434_wdt_ping(void)
{
	spin_lock(&rc32434_wdt_device.io_lock);
	writel(0, &wdt_reg->wtcount);
	spin_unlock(&rc32434_wdt_device.io_lock);
}

static int rc32434_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &rc32434_wdt_device.inuse))
		return -EBUSY;

	if (nowayout)
		__module_get(THIS_MODULE);

	rc32434_wdt_start();
	rc32434_wdt_ping();

	return nonseekable_open(inode, file);
}

static int rc32434_wdt_release(struct inode *inode, struct file *file)
{
	if (expect_close == 42) {
		rc32434_wdt_stop();
		module_put(THIS_MODULE);
	} else {
		pr_crit("device closed unexpectedly. WDT will not stop!\n");
		rc32434_wdt_ping();
	}
	clear_bit(0, &rc32434_wdt_device.inuse);
	return 0;
}

static ssize_t rc32434_wdt_write(struct file *file, const char *data,
				size_t len, loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			/* In case it was set long ago */
			expect_close = 0;

			for (i = 0; i != len; i++) {
				char c;
				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					expect_close = 42;
			}
		}
		rc32434_wdt_ping();
		return len;
	}
	return 0;
}

static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd,
				unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int new_timeout;
	unsigned int value;
	static const struct watchdog_info ident = {
		.options =		WDIOF_SETTIMEOUT |
					WDIOF_KEEPALIVEPING |
					WDIOF_MAGICCLOSE,
		.identity =		"RC32434_WDT Watchdog",
	};
	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &ident, sizeof(ident)))
			return -EFAULT;
		break;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		value = 0;
		if (copy_to_user(argp, &value, sizeof(int)))
			return -EFAULT;
		break;
	case WDIOC_SETOPTIONS:
		if (copy_from_user(&value, argp, sizeof(int)))
			return -EFAULT;
		switch (value) {
		case WDIOS_ENABLECARD:
			rc32434_wdt_start();
			break;
		case WDIOS_DISABLECARD:
			rc32434_wdt_stop();
			break;
		default:
			return -EINVAL;
		}
		break;
	case WDIOC_KEEPALIVE:
		rc32434_wdt_ping();
		break;
	case WDIOC_SETTIMEOUT:
		if (copy_from_user(&new_timeout, argp, sizeof(int)))
			return -EFAULT;
		if (rc32434_wdt_set(new_timeout))
			return -EINVAL;
		/* Fall through */
	case WDIOC_GETTIMEOUT:
		return copy_to_user(argp, &timeout, sizeof(int));
	default:
		return -ENOTTY;
	}

	return 0;
}

static const struct file_operations rc32434_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= rc32434_wdt_write,
	.unlocked_ioctl	= rc32434_wdt_ioctl,
	.open		= rc32434_wdt_open,
	.release	= rc32434_wdt_release,
};

static struct miscdevice rc32434_wdt_miscdev = {
	.minor	= WATCHDOG_MINOR,
	.name	= "watchdog",
	.fops	= &rc32434_wdt_fops,
};

static int rc32434_wdt_probe(struct platform_device *pdev)
{
	int ret;
	struct resource *r;

	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb532_wdt_res");
	if (!r) {
		pr_err("failed to retrieve resources\n");
		return -ENODEV;
	}

	wdt_reg = ioremap_nocache(r->start, resource_size(r));
	if (!wdt_reg) {
		pr_err("failed to remap I/O resources\n");
		return -ENXIO;
	}

	spin_lock_init(&rc32434_wdt_device.io_lock);

	/* Make sure the watchdog is not running */
	rc32434_wdt_stop();

	/* Check that the heartbeat value is within it's range;
	 * if not reset to the default */
	if (rc32434_wdt_set(timeout)) {
		rc32434_wdt_set(WATCHDOG_TIMEOUT);
		pr_info("timeout value must be between 0 and %d\n",
			WTCOMP2SEC((u32)-1));
	}

	ret = misc_register(&rc32434_wdt_miscdev);
	if (ret < 0) {
		pr_err("failed to register watchdog device\n");
		goto unmap;
	}

	pr_info("Watchdog Timer version " VERSION ", timer margin: %d sec\n",
		timeout);

	return 0;

unmap:
	iounmap(wdt_reg);
	return ret;
}

static int rc32434_wdt_remove(struct platform_device *pdev)
{
	misc_deregister(&rc32434_wdt_miscdev);
	iounmap(wdt_reg);
	return 0;
}

static void rc32434_wdt_shutdown(struct platform_device *pdev)
{
	rc32434_wdt_stop();
}

static struct platform_driver rc32434_wdt_driver = {
	.probe		= rc32434_wdt_probe,
	.remove		= rc32434_wdt_remove,
	.shutdown	= rc32434_wdt_shutdown,
	.driver		= {
			.name = "rc32434_wdt",
	}
};

module_platform_driver(rc32434_wdt_driver);

MODULE_AUTHOR("Ondrej Zajicek <santiago@crfreenet.org>,"
		"Florian Fainelli <florian@openwrt.org>");
MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);