2 * Watchdog driver for the BCM963xx devices
4 * Copyright (C) 2007 OpenWrt.org
5 * Florian Fainelli <florian@openwrt.org>
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
13 #include <linux/module.h>
14 #include <linux/types.h>
15 #include <linux/errno.h>
16 #include <linux/miscdevice.h>
18 #include <linux/init.h>
19 #include <linux/notifier.h>
20 #include <linux/watchdog.h>
21 #include <linux/timer.h>
22 #include <linux/jiffies.h>
23 #include <linux/completion.h>
24 #include <linux/ioport.h>
26 typedef struct bcm963xx_timer {
27 unsigned short unused0;
28 unsigned char timer_mask;
32 unsigned char timer_ints;
37 unsigned long timer_ctl0;
38 unsigned long timer_ctl1;
39 unsigned long timer_ctl2;
40 #define TIMERENABLE 0x80000000
41 #define RSTCNTCLR 0x40000000
42 unsigned long timer_cnt0;
43 unsigned long timer_cnt1;
44 unsigned long timer_cnt2;
45 unsigned long wdt_def_count;
47 /* Write 0xff00 0x00ff to Start timer
48 * Write 0xee00 0x00ee to Stop and re-load default count
49 * Read from this register returns current watch dog count
51 unsigned long wdt_ctl;
53 /* Number of 40-MHz ticks for WD Reset pulse to last */
54 unsigned long wdt_rst_count;
57 static struct bcm963xx_wdt_device {
58 struct completion stop;
60 struct timer_list timer;
64 } bcm963xx_wdt_device;
66 static int ticks = 1000;
68 #define WDT_BASE 0xfffe0200
69 #define WDT ((volatile bcm963xx_timer * const) WDT_BASE)
71 #define BCM963XX_INTERVAL (HZ/10+1)
73 static void bcm963xx_wdt_trigger(unsigned long unused)
75 if (bcm963xx_wdt_device.running)
78 /* Load the default ticking value into the reset counter register */
79 WDT->wdt_rst_count = bcm963xx_wdt_device.default_ticks;
81 if (bcm963xx_wdt_device.queue && ticks) {
82 bcm963xx_wdt_device.timer.expires = jiffies + BCM963XX_INTERVAL;
83 add_timer(&bcm963xx_wdt_device.timer);
86 complete(&bcm963xx_wdt_device.stop);
90 static void bcm963xx_wdt_reset(void)
92 ticks = bcm963xx_wdt_device.default_ticks;
93 /* Also reload default count */
94 WDT->wdt_def_count = ticks;
95 WDT->wdt_ctl = 0xee00;
96 WDT->wdt_ctl = 0x00ee;
99 static void bcm963xx_wdt_start(void)
101 if (!bcm963xx_wdt_device.queue) {
102 bcm963xx_wdt_device.queue;
103 /* Enable the watchdog by writing 0xff00 ,then 0x00ff to the control register */
104 WDT->wdt_ctl = 0xff00;
105 WDT->wdt_ctl = 0x00ff;
106 bcm963xx_wdt_device.timer.expires = jiffies + BCM963XX_INTERVAL;
107 add_timer(&bcm963xx_wdt_device.timer);
109 bcm963xx_wdt_device.running++;
112 static int bcm963xx_wdt_stop(void)
114 if (bcm963xx_wdt_device.running)
115 bcm963xx_wdt_device.running = 0;
117 ticks = bcm963xx_wdt_device.default_ticks;
119 /* Stop the watchdog by writing 0xee00 then 0x00ee to the control register */
120 WDT->wdt_ctl = 0xee00;
121 WDT->wdt_ctl = 0x00ee;
126 static int bcm963xx_wdt_open(struct inode *inode, struct file *file)
128 if (test_and_set_bit(0, &bcm963xx_wdt_device.inuse))
130 return nonseekable_open(inode, file);
133 static int bcm963xx_wdt_release(struct inode *inode, struct file *file)
135 clear_bit(0, &bcm963xx_wdt_device.inuse);
139 static int bcm963xx_wdt_ioctl(struct inode *inode, struct file *file,
140 unsigned int cmd, unsigned long arg)
142 void __user *argp = (void __user *)arg;
145 static struct watchdog_info ident = {
146 .options = WDIOF_CARDRESET,
147 .identity = "BCM963xx WDT",
151 case WDIOC_KEEPALIVE:
152 bcm963xx_wdt_reset();
154 case WDIOC_GETSTATUS:
155 /* Reading from the control register will return the current value */
156 value = WDT->wdt_ctl;
157 if ( copy_to_user(argp, &value, sizeof(int)) )
160 case WDIOC_GETSUPPORT:
161 if ( copy_to_user(argp, &ident, sizeof(ident)) )
164 case WDIOC_SETOPTIONS:
165 if ( copy_from_user(&value, argp, sizeof(int)) )
168 case WDIOS_ENABLECARD:
169 bcm963xx_wdt_start();
171 case WDIOS_DISABLECARD:
184 static int bcm963xx_wdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
188 bcm963xx_wdt_reset();
192 static const struct file_operations bcm963xx_wdt_fops = {
193 .owner = THIS_MODULE,
195 .write = bcm963xx_wdt_write,
196 .ioctl = bcm963xx_wdt_ioctl,
197 .open = bcm963xx_wdt_open,
198 .release = bcm963xx_wdt_release,
201 static struct miscdevice bcm963xx_wdt_miscdev = {
202 .minor = WATCHDOG_MINOR,
204 .fops = &bcm963xx_wdt_fops,
207 static void __exit bcm963xx_wdt_exit(void)
209 if (bcm963xx_wdt_device.queue ){
210 bcm963xx_wdt_device.queue = 0;
211 wait_for_completion(&bcm963xx_wdt_device.stop);
213 misc_deregister(&bcm963xx_wdt_miscdev);
216 static int __init bcm963xx_wdt_init(void)
220 printk("Broadcom BCM963xx Watchdog timer\n");
222 ret = misc_register(&bcm963xx_wdt_miscdev);
224 printk(KERN_CRIT "Cannot register miscdev on minor=%d (err=%d)\n", WATCHDOG_MINOR, ret);
227 init_completion(&bcm963xx_wdt_device.stop);
228 bcm963xx_wdt_device.queue = 0;
230 clear_bit(0, &bcm963xx_wdt_device.inuse);
232 init_timer(&bcm963xx_wdt_device.timer);
233 bcm963xx_wdt_device.timer.function = bcm963xx_wdt_trigger;
234 bcm963xx_wdt_device.timer.data = 0;
236 bcm963xx_wdt_device.default_ticks = ticks;
241 module_init(bcm963xx_wdt_init);
242 module_exit(bcm963xx_wdt_exit);
244 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
245 MODULE_DESCRIPTION("Broadcom BCM963xx Watchdog driver");
246 MODULE_LICENSE("GPL");