2 * drivers/char/watchdog/ixp2000_wdt.c
4 * Watchdog driver for Intel IXP2000 network processors
6 * Adapted from the IXP4xx watchdog driver by Lennert Buytenhek.
7 * The original version carries these notices:
9 * Author: Deepak Saxena <dsaxena@plexity.net>
11 * Copyright 2004 (c) MontaVista, Software, Inc.
12 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
14 * This file is licensed under the terms of the GNU General Public
15 * License version 2. This program is licensed "as is" without any
16 * warranty of any kind, whether express or implied.
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/types.h>
24 #include <linux/timer.h>
25 #include <linux/kernel.h>
27 #include <linux/miscdevice.h>
28 #include <linux/watchdog.h>
29 #include <linux/init.h>
30 #include <linux/bitops.h>
31 #include <linux/uaccess.h>
32 #include <mach/hardware.h>
34 static bool nowayout = WATCHDOG_NOWAYOUT;
35 static unsigned int heartbeat = 60; /* (secs) Default is 1 minute */
36 static unsigned long wdt_status;
37 static DEFINE_SPINLOCK(wdt_lock);
40 #define WDT_OK_TO_CLOSE 1
42 static unsigned long wdt_tick_rate;
44 static void wdt_enable(void)
47 ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) | WDT_RESET_ENABLE);
48 ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
49 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
50 ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 | TIMER_ENABLE);
51 spin_unlock(&wdt_lock);
54 static void wdt_disable(void)
57 ixp2000_reg_write(IXP2000_T4_CTL, 0);
58 spin_unlock(&wdt_lock);
61 static void wdt_keepalive(void)
64 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
65 spin_unlock(&wdt_lock);
68 static int ixp2000_wdt_open(struct inode *inode, struct file *file)
70 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
73 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
77 return nonseekable_open(inode, file);
80 static ssize_t ixp2000_wdt_write(struct file *file, const char *data,
81 size_t len, loff_t *ppos)
87 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
89 for (i = 0; i != len; i++) {
92 if (get_user(c, data + i))
95 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
105 static const struct watchdog_info ident = {
106 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
108 .identity = "IXP2000 Watchdog",
111 static long ixp2000_wdt_ioctl(struct file *file, unsigned int cmd,
118 case WDIOC_GETSUPPORT:
119 ret = copy_to_user((struct watchdog_info *)arg, &ident,
120 sizeof(ident)) ? -EFAULT : 0;
123 case WDIOC_GETSTATUS:
124 ret = put_user(0, (int *)arg);
127 case WDIOC_GETBOOTSTATUS:
128 ret = put_user(0, (int *)arg);
131 case WDIOC_KEEPALIVE:
136 case WDIOC_SETTIMEOUT:
137 ret = get_user(time, (int *)arg);
141 if (time <= 0 || time > 60) {
150 case WDIOC_GETTIMEOUT:
151 ret = put_user(heartbeat, (int *)arg);
158 static int ixp2000_wdt_release(struct inode *inode, struct file *file)
160 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
163 pr_crit("Device closed unexpectedly - timer will not stop\n");
164 clear_bit(WDT_IN_USE, &wdt_status);
165 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
171 static const struct file_operations ixp2000_wdt_fops = {
172 .owner = THIS_MODULE,
174 .write = ixp2000_wdt_write,
175 .unlocked_ioctl = ixp2000_wdt_ioctl,
176 .open = ixp2000_wdt_open,
177 .release = ixp2000_wdt_release,
180 static struct miscdevice ixp2000_wdt_miscdev = {
181 .minor = WATCHDOG_MINOR,
183 .fops = &ixp2000_wdt_fops,
186 static int __init ixp2000_wdt_init(void)
188 if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
189 pr_info("Unable to use IXP2000 watchdog due to IXP2800 erratum #25\n");
192 wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256;
193 return misc_register(&ixp2000_wdt_miscdev);
196 static void __exit ixp2000_wdt_exit(void)
198 misc_deregister(&ixp2000_wdt_miscdev);
201 module_init(ixp2000_wdt_init);
202 module_exit(ixp2000_wdt_exit);
204 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
205 MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");
207 module_param(heartbeat, int, 0);
208 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
210 module_param(nowayout, bool, 0);
211 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
213 MODULE_LICENSE("GPL");
214 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);