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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/* Watchdog timer for machines with the CS5535/CS5536 companion chip
2 *
3 * Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
4 * Copyright (C) 2009  Andres Salomon <dilinger@collabora.co.uk>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12
13#include <linux/module.h>
14#include <linux/moduleparam.h>
15#include <linux/types.h>
16#include <linux/miscdevice.h>
17#include <linux/watchdog.h>
18#include <linux/fs.h>
19#include <linux/platform_device.h>
20#include <linux/reboot.h>
21#include <linux/uaccess.h>
22
23#include <linux/cs5535.h>
24
25#define GEODEWDT_HZ 500
26#define GEODEWDT_SCALE 6
27#define GEODEWDT_MAX_SECONDS 131
28
29#define WDT_FLAGS_OPEN 1
30#define WDT_FLAGS_ORPHAN 2
31
32#define DRV_NAME "geodewdt"
33#define WATCHDOG_NAME "Geode GX/LX WDT"
34#define WATCHDOG_TIMEOUT 60
35
36static int timeout = WATCHDOG_TIMEOUT;
37module_param(timeout, int, 0);
38MODULE_PARM_DESC(timeout,
39	"Watchdog timeout in seconds. 1<= timeout <=131, default="
40				__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
41
42static int nowayout = 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
48static struct platform_device *geodewdt_platform_device;
49static unsigned long wdt_flags;
50static struct cs5535_mfgpt_timer *wdt_timer;
51static int safe_close;
52
53static void geodewdt_ping(void)
54{
55	/* Stop the counter */
56	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
57
58	/* Reset the counter */
59	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
60
61	/* Enable the counter */
62	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
63}
64
65static void geodewdt_disable(void)
66{
67	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
68	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
69}
70
71static int geodewdt_set_heartbeat(int val)
72{
73	if (val < 1 || val > GEODEWDT_MAX_SECONDS)
74		return -EINVAL;
75
76	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
77	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
78	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
79	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
80
81	timeout = val;
82	return 0;
83}
84
85static int geodewdt_open(struct inode *inode, struct file *file)
86{
87	if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
88		return -EBUSY;
89
90	if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
91		__module_get(THIS_MODULE);
92
93	geodewdt_ping();
94	return nonseekable_open(inode, file);
95}
96
97static int geodewdt_release(struct inode *inode, struct file *file)
98{
99	if (safe_close) {
100		geodewdt_disable();
101		module_put(THIS_MODULE);
102	} else {
103		printk(KERN_CRIT "Unexpected close - watchdog is not stopping.\n");
104		geodewdt_ping();
105
106		set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
107	}
108
109	clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
110	safe_close = 0;
111	return 0;
112}
113
114static ssize_t geodewdt_write(struct file *file, const char __user *data,
115				size_t len, loff_t *ppos)
116{
117	if (len) {
118		if (!nowayout) {
119			size_t i;
120			safe_close = 0;
121
122			for (i = 0; i != len; i++) {
123				char c;
124
125				if (get_user(c, data + i))
126					return -EFAULT;
127
128				if (c == 'V')
129					safe_close = 1;
130			}
131		}
132
133		geodewdt_ping();
134	}
135	return len;
136}
137
138static long geodewdt_ioctl(struct file *file, unsigned int cmd,
139				unsigned long arg)
140{
141	void __user *argp = (void __user *)arg;
142	int __user *p = argp;
143	int interval;
144
145	static const struct watchdog_info ident = {
146		.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
147		| WDIOF_MAGICCLOSE,
148		.firmware_version =     1,
149		.identity =             WATCHDOG_NAME,
150	};
151
152	switch (cmd) {
153	case WDIOC_GETSUPPORT:
154		return copy_to_user(argp, &ident,
155				    sizeof(ident)) ? -EFAULT : 0;
156		break;
157
158	case WDIOC_GETSTATUS:
159	case WDIOC_GETBOOTSTATUS:
160		return put_user(0, p);
161
162	case WDIOC_SETOPTIONS:
163	{
164		int options, ret = -EINVAL;
165
166		if (get_user(options, p))
167			return -EFAULT;
168
169		if (options & WDIOS_DISABLECARD) {
170			geodewdt_disable();
171			ret = 0;
172		}
173
174		if (options & WDIOS_ENABLECARD) {
175			geodewdt_ping();
176			ret = 0;
177		}
178
179		return ret;
180	}
181	case WDIOC_KEEPALIVE:
182		geodewdt_ping();
183		return 0;
184
185	case WDIOC_SETTIMEOUT:
186		if (get_user(interval, p))
187			return -EFAULT;
188
189		if (geodewdt_set_heartbeat(interval))
190			return -EINVAL;
191	/* Fall through */
192	case WDIOC_GETTIMEOUT:
193		return put_user(timeout, p);
194
195	default:
196		return -ENOTTY;
197	}
198
199	return 0;
200}
201
202static const struct file_operations geodewdt_fops = {
203	.owner          = THIS_MODULE,
204	.llseek         = no_llseek,
205	.write          = geodewdt_write,
206	.unlocked_ioctl = geodewdt_ioctl,
207	.open           = geodewdt_open,
208	.release        = geodewdt_release,
209};
210
211static struct miscdevice geodewdt_miscdev = {
212	.minor = WATCHDOG_MINOR,
213	.name = "watchdog",
214	.fops = &geodewdt_fops,
215};
216
217static int __devinit geodewdt_probe(struct platform_device *dev)
218{
219	int ret;
220
221	wdt_timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
222	if (!wdt_timer) {
223		printk(KERN_ERR "geodewdt:  No timers were available\n");
224		return -ENODEV;
225	}
226
227	/* Set up the timer */
228
229	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
230			  GEODEWDT_SCALE | (3 << 8));
231
232	/* Set up comparator 2 to reset when the event fires */
233	cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);
234
235	/* Set up the initial timeout */
236
237	cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
238		timeout * GEODEWDT_HZ);
239
240	ret = misc_register(&geodewdt_miscdev);
241
242	return ret;
243}
244
245static int __devexit geodewdt_remove(struct platform_device *dev)
246{
247	misc_deregister(&geodewdt_miscdev);
248	return 0;
249}
250
251static void geodewdt_shutdown(struct platform_device *dev)
252{
253	geodewdt_disable();
254}
255
256static struct platform_driver geodewdt_driver = {
257	.probe		= geodewdt_probe,
258	.remove		= __devexit_p(geodewdt_remove),
259	.shutdown	= geodewdt_shutdown,
260	.driver		= {
261		.owner	= THIS_MODULE,
262		.name	= DRV_NAME,
263	},
264};
265
266static int __init geodewdt_init(void)
267{
268	int ret;
269
270	ret = platform_driver_register(&geodewdt_driver);
271	if (ret)
272		return ret;
273
274	geodewdt_platform_device = platform_device_register_simple(DRV_NAME,
275								-1, NULL, 0);
276	if (IS_ERR(geodewdt_platform_device)) {
277		ret = PTR_ERR(geodewdt_platform_device);
278		goto err;
279	}
280
281	return 0;
282err:
283	platform_driver_unregister(&geodewdt_driver);
284	return ret;
285}
286
287static void __exit geodewdt_exit(void)
288{
289	platform_device_unregister(geodewdt_platform_device);
290	platform_driver_unregister(&geodewdt_driver);
291}
292
293module_init(geodewdt_init);
294module_exit(geodewdt_exit);
295
296MODULE_AUTHOR("Advanced Micro Devices, Inc");
297MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
298MODULE_LICENSE("GPL");
299MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
300