Remove obsolete #include <linux/config.h>
[linux-3.10.git] / drivers / char / watchdog / ixp2000_wdt.c
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/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/types.h>
22 #include <linux/kernel.h>
23 #include <linux/fs.h>
24 #include <linux/miscdevice.h>
25 #include <linux/watchdog.h>
26 #include <linux/init.h>
27 #include <linux/bitops.h>
28
29 #include <asm/hardware.h>
30 #include <asm/uaccess.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
36 #define WDT_IN_USE              0
37 #define WDT_OK_TO_CLOSE         1
38
39 static unsigned long wdt_tick_rate;
40
41 static void
42 wdt_enable(void)
43 {
44         ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) | WDT_RESET_ENABLE);
45         ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
46         ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
47         ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 | TIMER_ENABLE);
48 }
49
50 static void
51 wdt_disable(void)
52 {
53         ixp2000_reg_write(IXP2000_T4_CTL, 0);
54 }
55
56 static void
57 wdt_keepalive(void)
58 {
59         ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
60 }
61
62 static int
63 ixp2000_wdt_open(struct inode *inode, struct file *file)
64 {
65         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
66                 return -EBUSY;
67
68         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
69
70         wdt_enable();
71
72         return nonseekable_open(inode, file);
73 }
74
75 static ssize_t
76 ixp2000_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
77 {
78         if (len) {
79                 if (!nowayout) {
80                         size_t i;
81
82                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
83
84                         for (i = 0; i != len; i++) {
85                                 char c;
86
87                                 if (get_user(c, data + i))
88                                         return -EFAULT;
89                                 if (c == 'V')
90                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
91                         }
92                 }
93                 wdt_keepalive();
94         }
95
96         return len;
97 }
98
99
100 static struct watchdog_info ident = {
101         .options        = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
102                                 WDIOF_KEEPALIVEPING,
103         .identity       = "IXP2000 Watchdog",
104 };
105
106 static int
107 ixp2000_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
108                         unsigned long arg)
109 {
110         int ret = -ENOIOCTLCMD;
111         int time;
112
113         switch (cmd) {
114         case WDIOC_GETSUPPORT:
115                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
116                                    sizeof(ident)) ? -EFAULT : 0;
117                 break;
118
119         case WDIOC_GETSTATUS:
120                 ret = put_user(0, (int *)arg);
121                 break;
122
123         case WDIOC_GETBOOTSTATUS:
124                 ret = put_user(0, (int *)arg);
125                 break;
126
127         case WDIOC_SETTIMEOUT:
128                 ret = get_user(time, (int *)arg);
129                 if (ret)
130                         break;
131
132                 if (time <= 0 || time > 60) {
133                         ret = -EINVAL;
134                         break;
135                 }
136
137                 heartbeat = time;
138                 wdt_keepalive();
139                 /* Fall through */
140
141         case WDIOC_GETTIMEOUT:
142                 ret = put_user(heartbeat, (int *)arg);
143                 break;
144
145         case WDIOC_KEEPALIVE:
146                 wdt_enable();
147                 ret = 0;
148                 break;
149         }
150
151         return ret;
152 }
153
154 static int
155 ixp2000_wdt_release(struct inode *inode, struct file *file)
156 {
157         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
158                 wdt_disable();
159         } else {
160                 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
161                                         "timer will not stop\n");
162         }
163
164         clear_bit(WDT_IN_USE, &wdt_status);
165         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
166
167         return 0;
168 }
169
170
171 static struct file_operations ixp2000_wdt_fops =
172 {
173         .owner          = THIS_MODULE,
174         .llseek         = no_llseek,
175         .write          = ixp2000_wdt_write,
176         .ioctl          = ixp2000_wdt_ioctl,
177         .open           = ixp2000_wdt_open,
178         .release        = ixp2000_wdt_release,
179 };
180
181 static struct miscdevice ixp2000_wdt_miscdev =
182 {
183         .minor          = WATCHDOG_MINOR,
184         .name           = "watchdog",
185         .fops           = &ixp2000_wdt_fops,
186 };
187
188 static int __init ixp2000_wdt_init(void)
189 {
190         if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
191                 printk(KERN_INFO "Unable to use IXP2000 watchdog due to IXP2800 erratum #25.\n");
192                 return -EIO;
193         }
194
195         wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256;
196
197         return misc_register(&ixp2000_wdt_miscdev);
198 }
199
200 static void __exit ixp2000_wdt_exit(void)
201 {
202         misc_deregister(&ixp2000_wdt_miscdev);
203 }
204
205 module_init(ixp2000_wdt_init);
206 module_exit(ixp2000_wdt_exit);
207
208 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net">);
209 MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");
210
211 module_param(heartbeat, int, 0);
212 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
213
214 module_param(nowayout, int, 0);
215 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
216
217 MODULE_LICENSE("GPL");
218 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
219