cris: add arch/cris/include/asm/serial.h
[linux-2.6/next.git] / drivers / watchdog / ep93xx_wdt.c
blob726b7df61fd08b366a728fb5be0c793235b4d585
1 /*
2 * Watchdog driver for Cirrus Logic EP93xx family of devices.
4 * Copyright (c) 2004 Ray Lehtiniemi
5 * Copyright (c) 2006 Tower Technologies
6 * Based on ep93xx driver, bits from alim7101_wdt.c
8 * Authors: Ray Lehtiniemi <rayl@mail.com>,
9 * Alessandro Zummo <a.zummo@towertech.it>
11 * This file is licensed under the terms of the GNU General Public
12 * License version 2. This program is licensed "as is" without any
13 * warranty of any kind, whether express or implied.
15 * This watchdog fires after 250msec, which is a too short interval
16 * for us to rely on the user space daemon alone. So we ping the
17 * wdt each ~200msec and eventually stop doing it if the user space
18 * daemon dies.
20 * TODO:
22 * - Test last reset from watchdog status
23 * - Add a few missing ioctls
26 #include <linux/module.h>
27 #include <linux/fs.h>
28 #include <linux/miscdevice.h>
29 #include <linux/watchdog.h>
30 #include <linux/timer.h>
31 #include <linux/uaccess.h>
32 #include <linux/io.h>
33 #include <mach/hardware.h>
35 #define WDT_VERSION "0.3"
36 #define PFX "ep93xx_wdt: "
38 /* default timeout (secs) */
39 #define WDT_TIMEOUT 30
41 static int nowayout = WATCHDOG_NOWAYOUT;
42 static int timeout = WDT_TIMEOUT;
44 static struct timer_list timer;
45 static unsigned long next_heartbeat;
46 static unsigned long wdt_status;
47 static unsigned long boot_status;
49 #define WDT_IN_USE 0
50 #define WDT_OK_TO_CLOSE 1
52 #define EP93XX_WDT_REG(x) (EP93XX_WATCHDOG_BASE + (x))
53 #define EP93XX_WDT_WATCHDOG EP93XX_WDT_REG(0x00)
54 #define EP93XX_WDT_WDSTATUS EP93XX_WDT_REG(0x04)
56 /* reset the wdt every ~200ms */
57 #define WDT_INTERVAL (HZ/5)
59 static void wdt_enable(void)
61 __raw_writew(0xaaaa, EP93XX_WDT_WATCHDOG);
64 static void wdt_disable(void)
66 __raw_writew(0xaa55, EP93XX_WDT_WATCHDOG);
69 static inline void wdt_ping(void)
71 __raw_writew(0x5555, EP93XX_WDT_WATCHDOG);
74 static void wdt_startup(void)
76 next_heartbeat = jiffies + (timeout * HZ);
78 wdt_enable();
79 mod_timer(&timer, jiffies + WDT_INTERVAL);
82 static void wdt_shutdown(void)
84 del_timer_sync(&timer);
85 wdt_disable();
88 static void wdt_keepalive(void)
90 /* user land ping */
91 next_heartbeat = jiffies + (timeout * HZ);
94 static int ep93xx_wdt_open(struct inode *inode, struct file *file)
96 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
97 return -EBUSY;
99 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
101 wdt_startup();
103 return nonseekable_open(inode, file);
106 static ssize_t
107 ep93xx_wdt_write(struct file *file, const char __user *data, size_t len,
108 loff_t *ppos)
110 if (len) {
111 if (!nowayout) {
112 size_t i;
114 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
116 for (i = 0; i != len; i++) {
117 char c;
119 if (get_user(c, data + i))
120 return -EFAULT;
122 if (c == 'V')
123 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
124 else
125 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
128 wdt_keepalive();
131 return len;
134 static const struct watchdog_info ident = {
135 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE,
136 .identity = "EP93xx Watchdog",
139 static long ep93xx_wdt_ioctl(struct file *file,
140 unsigned int cmd, unsigned long arg)
142 int ret = -ENOTTY;
144 switch (cmd) {
145 case WDIOC_GETSUPPORT:
146 ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
147 sizeof(ident)) ? -EFAULT : 0;
148 break;
150 case WDIOC_GETSTATUS:
151 ret = put_user(0, (int __user *)arg);
152 break;
154 case WDIOC_GETBOOTSTATUS:
155 ret = put_user(boot_status, (int __user *)arg);
156 break;
158 case WDIOC_KEEPALIVE:
159 wdt_keepalive();
160 ret = 0;
161 break;
163 case WDIOC_GETTIMEOUT:
164 /* actually, it is 0.250 seconds.... */
165 ret = put_user(1, (int __user *)arg);
166 break;
168 return ret;
171 static int ep93xx_wdt_release(struct inode *inode, struct file *file)
173 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
174 wdt_shutdown();
175 else
176 printk(KERN_CRIT PFX
177 "Device closed unexpectedly - timer will not stop\n");
179 clear_bit(WDT_IN_USE, &wdt_status);
180 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
182 return 0;
185 static const struct file_operations ep93xx_wdt_fops = {
186 .owner = THIS_MODULE,
187 .write = ep93xx_wdt_write,
188 .unlocked_ioctl = ep93xx_wdt_ioctl,
189 .open = ep93xx_wdt_open,
190 .release = ep93xx_wdt_release,
191 .llseek = no_llseek,
194 static struct miscdevice ep93xx_wdt_miscdev = {
195 .minor = WATCHDOG_MINOR,
196 .name = "watchdog",
197 .fops = &ep93xx_wdt_fops,
200 static void ep93xx_timer_ping(unsigned long data)
202 if (time_before(jiffies, next_heartbeat))
203 wdt_ping();
205 /* Re-set the timer interval */
206 mod_timer(&timer, jiffies + WDT_INTERVAL);
209 static int __init ep93xx_wdt_init(void)
211 int err;
213 err = misc_register(&ep93xx_wdt_miscdev);
215 boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0;
217 printk(KERN_INFO PFX "EP93XX watchdog, driver version "
218 WDT_VERSION "%s\n",
219 (__raw_readl(EP93XX_WDT_WATCHDOG) & 0x08)
220 ? " (nCS1 disable detected)" : "");
222 if (timeout < 1 || timeout > 3600) {
223 timeout = WDT_TIMEOUT;
224 printk(KERN_INFO PFX
225 "timeout value must be 1<=x<=3600, using %d\n",
226 timeout);
229 setup_timer(&timer, ep93xx_timer_ping, 1);
230 return err;
233 static void __exit ep93xx_wdt_exit(void)
235 wdt_shutdown();
236 misc_deregister(&ep93xx_wdt_miscdev);
239 module_init(ep93xx_wdt_init);
240 module_exit(ep93xx_wdt_exit);
242 module_param(nowayout, int, 0);
243 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
245 module_param(timeout, int, 0);
246 MODULE_PARM_DESC(timeout,
247 "Watchdog timeout in seconds. (1<=timeout<=3600, default="
248 __MODULE_STRING(WDT_TIMEOUT) ")");
250 MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>,"
251 "Alessandro Zummo <a.zummo@towertech.it>");
252 MODULE_DESCRIPTION("EP93xx Watchdog");
253 MODULE_LICENSE("GPL");
254 MODULE_VERSION(WDT_VERSION);
255 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);