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  • only in /asuswrt-rt-n18u-9.0.0.4.380.2695/release/src-rt-6.x.4708/linux/linux-2.6/drivers/watchdog/
1/*
2 *  Watchdog driver for Broadcom BCM47XX
3 *
4 *  Copyright (C) 2008 Aleksandar Radovanovic <biblbroks@sezampro.rs>
5 *  Copyright (C) 2009 Matthieu CASTET <castet.matthieu@free.fr>
6 *
7 *  This program is free software; you can redistribute it and/or
8 *  modify it under the terms of the GNU General Public License
9 *  as published by the Free Software Foundation; either version
10 *  2 of the License, or (at your option) any later version.
11 */
12
13#include <linux/bitops.h>
14#include <linux/errno.h>
15#include <linux/fs.h>
16#include <linux/init.h>
17#include <linux/kernel.h>
18#include <linux/miscdevice.h>
19#include <linux/module.h>
20#include <linux/moduleparam.h>
21#include <linux/reboot.h>
22#include <linux/types.h>
23#include <linux/uaccess.h>
24#include <linux/watchdog.h>
25#include <linux/timer.h>
26#include <linux/jiffies.h>
27#include <linux/ssb/ssb_embedded.h>
28#include <asm/mach-bcm47xx/bcm47xx.h>
29
30#define DRV_NAME		"bcm47xx_wdt"
31
32#define WDT_DEFAULT_TIME	30	/* seconds */
33#define WDT_MAX_TIME		255	/* seconds */
34
35static int wdt_time = WDT_DEFAULT_TIME;
36static int nowayout = WATCHDOG_NOWAYOUT;
37
38module_param(wdt_time, int, 0);
39MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
40				__MODULE_STRING(WDT_DEFAULT_TIME) ")");
41
42#ifdef CONFIG_WATCHDOG_NOWAYOUT
43module_param(nowayout, int, 0);
44MODULE_PARM_DESC(nowayout,
45		"Watchdog cannot be stopped once started (default="
46				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
47#endif
48
49static unsigned long bcm47xx_wdt_busy;
50static char expect_release;
51static struct timer_list wdt_timer;
52static atomic_t ticks;
53
54static inline void bcm47xx_wdt_hw_start(void)
55{
56	/* this is 2,5s on 100Mhz clock  and 2s on 133 Mhz */
57	ssb_watchdog_timer_set(&ssb_bcm47xx, 0xfffffff);
58}
59
60static inline int bcm47xx_wdt_hw_stop(void)
61{
62	return ssb_watchdog_timer_set(&ssb_bcm47xx, 0);
63}
64
65static void bcm47xx_timer_tick(unsigned long unused)
66{
67	if (!atomic_dec_and_test(&ticks)) {
68		bcm47xx_wdt_hw_start();
69		mod_timer(&wdt_timer, jiffies + HZ);
70	} else {
71		printk(KERN_CRIT DRV_NAME "Watchdog will fire soon!!!\n");
72	}
73}
74
75static inline void bcm47xx_wdt_pet(void)
76{
77	atomic_set(&ticks, wdt_time);
78}
79
80static void bcm47xx_wdt_start(void)
81{
82	bcm47xx_wdt_pet();
83	bcm47xx_timer_tick(0);
84}
85
86static void bcm47xx_wdt_pause(void)
87{
88	del_timer_sync(&wdt_timer);
89	bcm47xx_wdt_hw_stop();
90}
91
92static void bcm47xx_wdt_stop(void)
93{
94	bcm47xx_wdt_pause();
95}
96
97static int bcm47xx_wdt_settimeout(int new_time)
98{
99	if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
100		return -EINVAL;
101
102	wdt_time = new_time;
103	return 0;
104}
105
106static int bcm47xx_wdt_open(struct inode *inode, struct file *file)
107{
108	if (test_and_set_bit(0, &bcm47xx_wdt_busy))
109		return -EBUSY;
110
111	bcm47xx_wdt_start();
112	return nonseekable_open(inode, file);
113}
114
115static int bcm47xx_wdt_release(struct inode *inode, struct file *file)
116{
117	if (expect_release == 42) {
118		bcm47xx_wdt_stop();
119	} else {
120		printk(KERN_CRIT DRV_NAME
121			": Unexpected close, not stopping watchdog!\n");
122		bcm47xx_wdt_start();
123	}
124
125	clear_bit(0, &bcm47xx_wdt_busy);
126	expect_release = 0;
127	return 0;
128}
129
130static ssize_t bcm47xx_wdt_write(struct file *file, const char __user *data,
131				size_t len, loff_t *ppos)
132{
133	if (len) {
134		if (!nowayout) {
135			size_t i;
136
137			expect_release = 0;
138
139			for (i = 0; i != len; i++) {
140				char c;
141				if (get_user(c, data + i))
142					return -EFAULT;
143				if (c == 'V')
144					expect_release = 42;
145			}
146		}
147		bcm47xx_wdt_pet();
148	}
149	return len;
150}
151
152static const struct watchdog_info bcm47xx_wdt_info = {
153	.identity 	= DRV_NAME,
154	.options 	= WDIOF_SETTIMEOUT |
155				WDIOF_KEEPALIVEPING |
156				WDIOF_MAGICCLOSE,
157};
158
159static long bcm47xx_wdt_ioctl(struct file *file,
160					unsigned int cmd, unsigned long arg)
161{
162	void __user *argp = (void __user *)arg;
163	int __user *p = argp;
164	int new_value, retval = -EINVAL;
165
166	switch (cmd) {
167	case WDIOC_GETSUPPORT:
168		return copy_to_user(argp, &bcm47xx_wdt_info,
169				sizeof(bcm47xx_wdt_info)) ? -EFAULT : 0;
170
171	case WDIOC_GETSTATUS:
172	case WDIOC_GETBOOTSTATUS:
173		return put_user(0, p);
174
175	case WDIOC_SETOPTIONS:
176		if (get_user(new_value, p))
177			return -EFAULT;
178
179		if (new_value & WDIOS_DISABLECARD) {
180			bcm47xx_wdt_stop();
181			retval = 0;
182		}
183
184		if (new_value & WDIOS_ENABLECARD) {
185			bcm47xx_wdt_start();
186			retval = 0;
187		}
188
189		return retval;
190
191	case WDIOC_KEEPALIVE:
192		bcm47xx_wdt_pet();
193		return 0;
194
195	case WDIOC_SETTIMEOUT:
196		if (get_user(new_value, p))
197			return -EFAULT;
198
199		if (bcm47xx_wdt_settimeout(new_value))
200			return -EINVAL;
201
202		bcm47xx_wdt_pet();
203
204	case WDIOC_GETTIMEOUT:
205		return put_user(wdt_time, p);
206
207	default:
208		return -ENOTTY;
209	}
210}
211
212static int bcm47xx_wdt_notify_sys(struct notifier_block *this,
213	unsigned long code, void *unused)
214{
215	if (code == SYS_DOWN || code == SYS_HALT)
216		bcm47xx_wdt_stop();
217	return NOTIFY_DONE;
218}
219
220static const struct file_operations bcm47xx_wdt_fops = {
221	.owner		= THIS_MODULE,
222	.llseek		= no_llseek,
223	.unlocked_ioctl	= bcm47xx_wdt_ioctl,
224	.open		= bcm47xx_wdt_open,
225	.release	= bcm47xx_wdt_release,
226	.write		= bcm47xx_wdt_write,
227};
228
229static struct miscdevice bcm47xx_wdt_miscdev = {
230	.minor		= WATCHDOG_MINOR,
231	.name		= "watchdog",
232	.fops		= &bcm47xx_wdt_fops,
233};
234
235static struct notifier_block bcm47xx_wdt_notifier = {
236	.notifier_call = bcm47xx_wdt_notify_sys,
237};
238
239static int __init bcm47xx_wdt_init(void)
240{
241	int ret;
242
243	if (bcm47xx_wdt_hw_stop() < 0)
244		return -ENODEV;
245
246	setup_timer(&wdt_timer, bcm47xx_timer_tick, 0L);
247
248	if (bcm47xx_wdt_settimeout(wdt_time)) {
249		bcm47xx_wdt_settimeout(WDT_DEFAULT_TIME);
250		printk(KERN_INFO DRV_NAME ": "
251			"wdt_time value must be 0 < wdt_time < %d, using %d\n",
252			(WDT_MAX_TIME + 1), wdt_time);
253	}
254
255	ret = register_reboot_notifier(&bcm47xx_wdt_notifier);
256	if (ret)
257		return ret;
258
259	ret = misc_register(&bcm47xx_wdt_miscdev);
260	if (ret) {
261		unregister_reboot_notifier(&bcm47xx_wdt_notifier);
262		return ret;
263	}
264
265	printk(KERN_INFO "BCM47xx Watchdog Timer enabled (%d seconds%s)\n",
266				wdt_time, nowayout ? ", nowayout" : "");
267	return 0;
268}
269
270static void __exit bcm47xx_wdt_exit(void)
271{
272	if (!nowayout)
273		bcm47xx_wdt_stop();
274
275	misc_deregister(&bcm47xx_wdt_miscdev);
276
277	unregister_reboot_notifier(&bcm47xx_wdt_notifier);
278}
279
280module_init(bcm47xx_wdt_init);
281module_exit(bcm47xx_wdt_exit);
282
283MODULE_AUTHOR("Aleksandar Radovanovic");
284MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
285MODULE_LICENSE("GPL");
286MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
287