1 /*
2 * drivers/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/config.h>
20 #include <linux/module.h>
21 #include <linux/moduleparam.h>
22 #include <linux/types.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
30 #include <asm/hardware.h>
31 #include <asm/uaccess.h>
32
33 static int nowayout = WATCHDOG_NOWAYOUT;
34 static unsigned int heartbeat = 60; /* (secs) Default is 1 minute */
35 static unsigned long wdt_status;
36
37 #define WDT_IN_USE 0
38 #define WDT_OK_TO_CLOSE 1
39
40 static unsigned long wdt_tick_rate;
41
42 static void
43 wdt_enable(void)
44 {
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 }
50
51 static void
52 wdt_disable(void)
53 {
54 ixp2000_reg_write(IXP2000_T4_CTL, 0);
55 }
56
57 static void
58 wdt_keepalive(void)
59 {
60 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
61 }
62
63 static int
64 ixp2000_wdt_open(struct inode *inode, struct file *file)
65 {
66 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
67 return -EBUSY;
68
69 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
70
71 wdt_enable();
72
73 return nonseekable_open(inode, file);
74 }
75
76 static ssize_t
77 ixp2000_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
78 {
79 if (len) {
80 if (!nowayout) {
81 size_t i;
82
83 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
84
85 for (i = 0; i != len; i++) {
86 char c;
87
88 if (get_user(c, data + i))
89 return -EFAULT;
90 if (c == 'V')
91 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
92 }
93 }
94 wdt_keepalive();
95 }
96
97 return len;
98 }
99
100
101 static struct watchdog_info ident = {
102 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
103 WDIOF_KEEPALIVEPING,
104 .identity = "IXP2000 Watchdog",
105 };
106
107 static int
108 ixp2000_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
109 unsigned long arg)
110 {
111 int ret = -ENOIOCTLCMD;
112 int time;
113
114 switch (cmd) {
115 case WDIOC_GETSUPPORT:
116 ret = copy_to_user((struct watchdog_info *)arg, &ident,
117 sizeof(ident)) ? -EFAULT : 0;
118 break;
119
120 case WDIOC_GETSTATUS:
121 ret = put_user(0, (int *)arg);
122 break;
123
124 case WDIOC_GETBOOTSTATUS:
125 ret = put_user(0, (int *)arg);
126 break;
127
128 case WDIOC_SETTIMEOUT:
129 ret = get_user(time, (int *)arg);
130 if (ret)
131 break;
132
133 if (time <= 0 || time > 60) {
134 ret = -EINVAL;
135 break;
136 }
137
138 heartbeat = time;
139 wdt_keepalive();
140 /* Fall through */
141
142 case WDIOC_GETTIMEOUT:
143 ret = put_user(heartbeat, (int *)arg);
144 break;
145
146 case WDIOC_KEEPALIVE:
147 wdt_enable();
148 ret = 0;
149 break;
150 }
151
152 return ret;
153 }
154
155 static int
156 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 }
164
165 clear_bit(WDT_IN_USE, &wdt_status);
166 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
167
168 return 0;
169 }
170
171
172 static struct file_operations ixp2000_wdt_fops =
173 {
174 .owner = THIS_MODULE,
175 .llseek = no_llseek,
176 .write = ixp2000_wdt_write,
177 .ioctl = ixp2000_wdt_ioctl,
178 .open = ixp2000_wdt_open,
179 .release = ixp2000_wdt_release,
180 };
181
182 static struct miscdevice ixp2000_wdt_miscdev =
183 {
184 .minor = WATCHDOG_MINOR,
185 .name = "watchdog",
186 .fops = &ixp2000_wdt_fops,
187 };
188
189 static int __init ixp2000_wdt_init(void)
190 {
191 if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
192 printk(KERN_INFO "Unable to use IXP2000 watchdog due to IXP2800 erratum #25.\n");
193 return -EIO;
194 }
195
196 wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256;
197
198 return misc_register(&ixp2000_wdt_miscdev);
199 }
200
201 static void __exit ixp2000_wdt_exit(void)
202 {
203 misc_deregister(&ixp2000_wdt_miscdev);
204 }
205
206 module_init(ixp2000_wdt_init);
207 module_exit(ixp2000_wdt_exit);
208
209 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net">);
210 MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");
211
212 module_param(heartbeat, int, 0);
213 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
214
215 module_param(nowayout, int, 0);
216 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
217
218 MODULE_LICENSE("GPL");
219 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
220
221
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