xref: /linux/drivers/watchdog/bcm47xx_wdt.c (revision f2ee442115c9b6219083c019939a9cc0c9abb2f8) 
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 
35 static int wdt_time = WDT_DEFAULT_TIME;
36 static int nowayout = WATCHDOG_NOWAYOUT;
37 
38 module_param(wdt_time, int, 0);
39 MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
40 				__MODULE_STRING(WDT_DEFAULT_TIME) ")");
41 
42 #ifdef CONFIG_WATCHDOG_NOWAYOUT
43 module_param(nowayout, int, 0);
44 MODULE_PARM_DESC(nowayout,
45 		"Watchdog cannot be stopped once started (default="
46 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
47 #endif
48 
49 static unsigned long bcm47xx_wdt_busy;
50 static char expect_release;
51 static struct timer_list wdt_timer;
52 static atomic_t ticks;
53 
54 static inline void bcm47xx_wdt_hw_start(void)
55 {
56 	/* this is 2,5s on 100Mhz clock  and 2s on 133 Mhz */
57 	switch (bcm47xx_bus_type) {
58 #ifdef CONFIG_BCM47XX_SSB
59 	case BCM47XX_BUS_TYPE_SSB:
60 		ssb_watchdog_timer_set(&bcm47xx_bus.ssb, 0xfffffff);
61 		break;
62 #endif
63 #ifdef CONFIG_BCM47XX_BCMA
64 	case BCM47XX_BUS_TYPE_BCMA:
65 		bcma_chipco_watchdog_timer_set(&bcm47xx_bus.bcma.bus.drv_cc,
66 					       0xfffffff);
67 		break;
68 #endif
69 	}
70 }
71 
72 static inline int bcm47xx_wdt_hw_stop(void)
73 {
74 	switch (bcm47xx_bus_type) {
75 #ifdef CONFIG_BCM47XX_SSB
76 	case BCM47XX_BUS_TYPE_SSB:
77 		return ssb_watchdog_timer_set(&bcm47xx_bus.ssb, 0);
78 #endif
79 #ifdef CONFIG_BCM47XX_BCMA
80 	case BCM47XX_BUS_TYPE_BCMA:
81 		bcma_chipco_watchdog_timer_set(&bcm47xx_bus.bcma.bus.drv_cc, 0);
82 		return 0;
83 #endif
84 	}
85 	return -EINVAL;
86 }
87 
88 static void bcm47xx_timer_tick(unsigned long unused)
89 {
90 	if (!atomic_dec_and_test(&ticks)) {
91 		bcm47xx_wdt_hw_start();
92 		mod_timer(&wdt_timer, jiffies + HZ);
93 	} else {
94 		printk(KERN_CRIT DRV_NAME "Watchdog will fire soon!!!\n");
95 	}
96 }
97 
98 static inline void bcm47xx_wdt_pet(void)
99 {
100 	atomic_set(&ticks, wdt_time);
101 }
102 
103 static void bcm47xx_wdt_start(void)
104 {
105 	bcm47xx_wdt_pet();
106 	bcm47xx_timer_tick(0);
107 }
108 
109 static void bcm47xx_wdt_pause(void)
110 {
111 	del_timer_sync(&wdt_timer);
112 	bcm47xx_wdt_hw_stop();
113 }
114 
115 static void bcm47xx_wdt_stop(void)
116 {
117 	bcm47xx_wdt_pause();
118 }
119 
120 static int bcm47xx_wdt_settimeout(int new_time)
121 {
122 	if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
123 		return -EINVAL;
124 
125 	wdt_time = new_time;
126 	return 0;
127 }
128 
129 static int bcm47xx_wdt_open(struct inode *inode, struct file *file)
130 {
131 	if (test_and_set_bit(0, &bcm47xx_wdt_busy))
132 		return -EBUSY;
133 
134 	bcm47xx_wdt_start();
135 	return nonseekable_open(inode, file);
136 }
137 
138 static int bcm47xx_wdt_release(struct inode *inode, struct file *file)
139 {
140 	if (expect_release == 42) {
141 		bcm47xx_wdt_stop();
142 	} else {
143 		printk(KERN_CRIT DRV_NAME
144 			": Unexpected close, not stopping watchdog!\n");
145 		bcm47xx_wdt_start();
146 	}
147 
148 	clear_bit(0, &bcm47xx_wdt_busy);
149 	expect_release = 0;
150 	return 0;
151 }
152 
153 static ssize_t bcm47xx_wdt_write(struct file *file, const char __user *data,
154 				size_t len, loff_t *ppos)
155 {
156 	if (len) {
157 		if (!nowayout) {
158 			size_t i;
159 
160 			expect_release = 0;
161 
162 			for (i = 0; i != len; i++) {
163 				char c;
164 				if (get_user(c, data + i))
165 					return -EFAULT;
166 				if (c == 'V')
167 					expect_release = 42;
168 			}
169 		}
170 		bcm47xx_wdt_pet();
171 	}
172 	return len;
173 }
174 
175 static const struct watchdog_info bcm47xx_wdt_info = {
176 	.identity	= DRV_NAME,
177 	.options	= WDIOF_SETTIMEOUT |
178 				WDIOF_KEEPALIVEPING |
179 				WDIOF_MAGICCLOSE,
180 };
181 
182 static long bcm47xx_wdt_ioctl(struct file *file,
183 					unsigned int cmd, unsigned long arg)
184 {
185 	void __user *argp = (void __user *)arg;
186 	int __user *p = argp;
187 	int new_value, retval = -EINVAL;
188 
189 	switch (cmd) {
190 	case WDIOC_GETSUPPORT:
191 		return copy_to_user(argp, &bcm47xx_wdt_info,
192 				sizeof(bcm47xx_wdt_info)) ? -EFAULT : 0;
193 
194 	case WDIOC_GETSTATUS:
195 	case WDIOC_GETBOOTSTATUS:
196 		return put_user(0, p);
197 
198 	case WDIOC_SETOPTIONS:
199 		if (get_user(new_value, p))
200 			return -EFAULT;
201 
202 		if (new_value & WDIOS_DISABLECARD) {
203 			bcm47xx_wdt_stop();
204 			retval = 0;
205 		}
206 
207 		if (new_value & WDIOS_ENABLECARD) {
208 			bcm47xx_wdt_start();
209 			retval = 0;
210 		}
211 
212 		return retval;
213 
214 	case WDIOC_KEEPALIVE:
215 		bcm47xx_wdt_pet();
216 		return 0;
217 
218 	case WDIOC_SETTIMEOUT:
219 		if (get_user(new_value, p))
220 			return -EFAULT;
221 
222 		if (bcm47xx_wdt_settimeout(new_value))
223 			return -EINVAL;
224 
225 		bcm47xx_wdt_pet();
226 
227 	case WDIOC_GETTIMEOUT:
228 		return put_user(wdt_time, p);
229 
230 	default:
231 		return -ENOTTY;
232 	}
233 }
234 
235 static int bcm47xx_wdt_notify_sys(struct notifier_block *this,
236 	unsigned long code, void *unused)
237 {
238 	if (code == SYS_DOWN || code == SYS_HALT)
239 		bcm47xx_wdt_stop();
240 	return NOTIFY_DONE;
241 }
242 
243 static const struct file_operations bcm47xx_wdt_fops = {
244 	.owner		= THIS_MODULE,
245 	.llseek		= no_llseek,
246 	.unlocked_ioctl	= bcm47xx_wdt_ioctl,
247 	.open		= bcm47xx_wdt_open,
248 	.release	= bcm47xx_wdt_release,
249 	.write		= bcm47xx_wdt_write,
250 };
251 
252 static struct miscdevice bcm47xx_wdt_miscdev = {
253 	.minor		= WATCHDOG_MINOR,
254 	.name		= "watchdog",
255 	.fops		= &bcm47xx_wdt_fops,
256 };
257 
258 static struct notifier_block bcm47xx_wdt_notifier = {
259 	.notifier_call = bcm47xx_wdt_notify_sys,
260 };
261 
262 static int __init bcm47xx_wdt_init(void)
263 {
264 	int ret;
265 
266 	if (bcm47xx_wdt_hw_stop() < 0)
267 		return -ENODEV;
268 
269 	setup_timer(&wdt_timer, bcm47xx_timer_tick, 0L);
270 
271 	if (bcm47xx_wdt_settimeout(wdt_time)) {
272 		bcm47xx_wdt_settimeout(WDT_DEFAULT_TIME);
273 		printk(KERN_INFO DRV_NAME ": "
274 			"wdt_time value must be 0 < wdt_time < %d, using %d\n",
275 			(WDT_MAX_TIME + 1), wdt_time);
276 	}
277 
278 	ret = register_reboot_notifier(&bcm47xx_wdt_notifier);
279 	if (ret)
280 		return ret;
281 
282 	ret = misc_register(&bcm47xx_wdt_miscdev);
283 	if (ret) {
284 		unregister_reboot_notifier(&bcm47xx_wdt_notifier);
285 		return ret;
286 	}
287 
288 	printk(KERN_INFO "BCM47xx Watchdog Timer enabled (%d seconds%s)\n",
289 				wdt_time, nowayout ? ", nowayout" : "");
290 	return 0;
291 }
292 
293 static void __exit bcm47xx_wdt_exit(void)
294 {
295 	if (!nowayout)
296 		bcm47xx_wdt_stop();
297 
298 	misc_deregister(&bcm47xx_wdt_miscdev);
299 
300 	unregister_reboot_notifier(&bcm47xx_wdt_notifier);
301 }
302 
303 module_init(bcm47xx_wdt_init);
304 module_exit(bcm47xx_wdt_exit);
305 
306 MODULE_AUTHOR("Aleksandar Radovanovic");
307 MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
308 MODULE_LICENSE("GPL");
309 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
310