1 /*
2 * drivers/char/watchdog/ixp2000_wdt.c
3 *
4 * Watchdog driver for Intel IXP2000 network processors
5 *
6 * Adapted from the IXP4xx watchdog driver by Lennert Buytenhek.
7 * The original version carries these notices:
8 *
9 * Author: Deepak Saxena <dsaxena@plexity.net>
10 *
11 * Copyright 2004 (c) MontaVista, Software, Inc.
12 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
13 *
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.
17 */
18
19 #include <linux/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/types.h>
22 #include <linux/timer.h>
23 #include <linux/kernel.h>
24 #include <linux/fs.h>
25 #include <linux/miscdevice.h>
26 #include <linux/watchdog.h>
27 #include <linux/init.h>
28 #include <linux/bitops.h>
29 #include <linux/uaccess.h>
30 #include <mach/hardware.h>
31
32 static int nowayout = WATCHDOG_NOWAYOUT;
33 static unsigned int heartbeat = 60; /* (secs) Default is 1 minute */
34 static unsigned long wdt_status;
35 static DEFINE_SPINLOCK(wdt_lock);
36
37 #define WDT_IN_USE 0
38 #define WDT_OK_TO_CLOSE 1
39
40 static unsigned long wdt_tick_rate;
41
wdt_enable(void)42 static void wdt_enable(void)
43 {
44 spin_lock(&wdt_lock);
45 ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) | WDT_RESET_ENABLE);
46 ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
47 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
48 ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 | TIMER_ENABLE);
49 spin_unlock(&wdt_lock);
50 }
51
wdt_disable(void)52 static void wdt_disable(void)
53 {
54 spin_lock(&wdt_lock);
55 ixp2000_reg_write(IXP2000_T4_CTL, 0);
56 spin_unlock(&wdt_lock);
57 }
58
wdt_keepalive(void)59 static void wdt_keepalive(void)
60 {
61 spin_lock(&wdt_lock);
62 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
63 spin_unlock(&wdt_lock);
64 }
65
ixp2000_wdt_open(struct inode * inode,struct file * file)66 static int ixp2000_wdt_open(struct inode *inode, struct file *file)
67 {
68 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
69 return -EBUSY;
70
71 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
72
73 wdt_enable();
74
75 return nonseekable_open(inode, file);
76 }
77
ixp2000_wdt_write(struct file * file,const char * data,size_t len,loff_t * ppos)78 static ssize_t ixp2000_wdt_write(struct file *file, const char *data,
79 size_t len, loff_t *ppos)
80 {
81 if (len) {
82 if (!nowayout) {
83 size_t i;
84
85 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
86
87 for (i = 0; i != len; i++) {
88 char c;
89
90 if (get_user(c, data + i))
91 return -EFAULT;
92 if (c == 'V')
93 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
94 }
95 }
96 wdt_keepalive();
97 }
98
99 return len;
100 }
101
102
103 static const struct watchdog_info ident = {
104 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
105 WDIOF_KEEPALIVEPING,
106 .identity = "IXP2000 Watchdog",
107 };
108
ixp2000_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)109 static long ixp2000_wdt_ioctl(struct file *file, unsigned int cmd,
110 unsigned long arg)
111 {
112 int ret = -ENOTTY;
113 int time;
114
115 switch (cmd) {
116 case WDIOC_GETSUPPORT:
117 ret = copy_to_user((struct watchdog_info *)arg, &ident,
118 sizeof(ident)) ? -EFAULT : 0;
119 break;
120
121 case WDIOC_GETSTATUS:
122 ret = put_user(0, (int *)arg);
123 break;
124
125 case WDIOC_GETBOOTSTATUS:
126 ret = put_user(0, (int *)arg);
127 break;
128
129 case WDIOC_KEEPALIVE:
130 wdt_enable();
131 ret = 0;
132 break;
133
134 case WDIOC_SETTIMEOUT:
135 ret = get_user(time, (int *)arg);
136 if (ret)
137 break;
138
139 if (time <= 0 || time > 60) {
140 ret = -EINVAL;
141 break;
142 }
143
144 heartbeat = time;
145 wdt_keepalive();
146 /* Fall through */
147
148 case WDIOC_GETTIMEOUT:
149 ret = put_user(heartbeat, (int *)arg);
150 break;
151 }
152
153 return ret;
154 }
155
ixp2000_wdt_release(struct inode * inode,struct file * file)156 static int ixp2000_wdt_release(struct inode *inode, struct file *file)
157 {
158 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
159 wdt_disable();
160 else
161 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
162 "timer will not stop\n");
163 clear_bit(WDT_IN_USE, &wdt_status);
164 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
165
166 return 0;
167 }
168
169
170 static const struct file_operations ixp2000_wdt_fops = {
171 .owner = THIS_MODULE,
172 .llseek = no_llseek,
173 .write = ixp2000_wdt_write,
174 .unlocked_ioctl = ixp2000_wdt_ioctl,
175 .open = ixp2000_wdt_open,
176 .release = ixp2000_wdt_release,
177 };
178
179 static struct miscdevice ixp2000_wdt_miscdev = {
180 .minor = WATCHDOG_MINOR,
181 .name = "watchdog",
182 .fops = &ixp2000_wdt_fops,
183 };
184
ixp2000_wdt_init(void)185 static int __init ixp2000_wdt_init(void)
186 {
187 if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
188 printk(KERN_INFO "Unable to use IXP2000 watchdog due to IXP2800 erratum #25.\n");
189 return -EIO;
190 }
191 wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256;
192 return misc_register(&ixp2000_wdt_miscdev);
193 }
194
ixp2000_wdt_exit(void)195 static void __exit ixp2000_wdt_exit(void)
196 {
197 misc_deregister(&ixp2000_wdt_miscdev);
198 }
199
200 module_init(ixp2000_wdt_init);
201 module_exit(ixp2000_wdt_exit);
202
203 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
204 MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");
205
206 module_param(heartbeat, int, 0);
207 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
208
209 module_param(nowayout, int, 0);
210 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
211
212 MODULE_LICENSE("GPL");
213 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
214
215