4fc2e9ac26f7c818768c0e6f1a05a78b789cd7e7
[sfrench/cifs-2.6.git] / drivers / watchdog / ixp4xx_wdt.c
1 /*
2  * drivers/char/watchdog/ixp4xx_wdt.c
3  *
4  * Watchdog driver for Intel IXP4xx network processors
5  *
6  * Author: Deepak Saxena <dsaxena@plexity.net>
7  *
8  * Copyright 2004 (c) MontaVista, Software, Inc.
9  * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
10  *
11  * This file is licensed under  the terms of the GNU General Public
12  * License version 2. This program is licensed "as is" without any
13  * warranty of any kind, whether express or implied.
14  */
15
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/types.h>
19 #include <linux/kernel.h>
20 #include <linux/fs.h>
21 #include <linux/miscdevice.h>
22 #include <linux/watchdog.h>
23 #include <linux/init.h>
24 #include <linux/bitops.h>
25 #include <linux/uaccess.h>
26 #include <mach/hardware.h>
27
28 static int nowayout = WATCHDOG_NOWAYOUT;
29 static int heartbeat = 60;      /* (secs) Default is 1 minute */
30 static unsigned long wdt_status;
31 static unsigned long boot_status;
32 static DEFINE_SPINLOCK(wdt_lock);
33
34 #define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
35
36 #define WDT_IN_USE              0
37 #define WDT_OK_TO_CLOSE         1
38
39 static void wdt_enable(void)
40 {
41         spin_lock(&wdt_lock);
42         *IXP4XX_OSWK = IXP4XX_WDT_KEY;
43         *IXP4XX_OSWE = 0;
44         *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
45         *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
46         *IXP4XX_OSWK = 0;
47         spin_unlock(&wdt_lock);
48 }
49
50 static void wdt_disable(void)
51 {
52         spin_lock(&wdt_lock);
53         *IXP4XX_OSWK = IXP4XX_WDT_KEY;
54         *IXP4XX_OSWE = 0;
55         *IXP4XX_OSWK = 0;
56         spin_unlock(&wdt_lock);
57 }
58
59 static int ixp4xx_wdt_open(struct inode *inode, struct file *file)
60 {
61         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
62                 return -EBUSY;
63
64         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
65         wdt_enable();
66         return nonseekable_open(inode, file);
67 }
68
69 static ssize_t
70 ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
71 {
72         if (len) {
73                 if (!nowayout) {
74                         size_t i;
75
76                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
77
78                         for (i = 0; i != len; i++) {
79                                 char c;
80
81                                 if (get_user(c, data + i))
82                                         return -EFAULT;
83                                 if (c == 'V')
84                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
85                         }
86                 }
87                 wdt_enable();
88         }
89         return len;
90 }
91
92 static const struct watchdog_info ident = {
93         .options        = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
94                           WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
95         .identity       = "IXP4xx Watchdog",
96 };
97
98
99 static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
100                                                         unsigned long arg)
101 {
102         int ret = -ENOTTY;
103         int time;
104
105         switch (cmd) {
106         case WDIOC_GETSUPPORT:
107                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
108                                    sizeof(ident)) ? -EFAULT : 0;
109                 break;
110
111         case WDIOC_GETSTATUS:
112                 ret = put_user(0, (int *)arg);
113                 break;
114
115         case WDIOC_GETBOOTSTATUS:
116                 ret = put_user(boot_status, (int *)arg);
117                 break;
118
119         case WDIOC_KEEPALIVE:
120                 wdt_enable();
121                 ret = 0;
122                 break;
123
124         case WDIOC_SETTIMEOUT:
125                 ret = get_user(time, (int *)arg);
126                 if (ret)
127                         break;
128
129                 if (time <= 0 || time > 60) {
130                         ret = -EINVAL;
131                         break;
132                 }
133
134                 heartbeat = time;
135                 wdt_enable();
136                 /* Fall through */
137
138         case WDIOC_GETTIMEOUT:
139                 ret = put_user(heartbeat, (int *)arg);
140                 break;
141         }
142         return ret;
143 }
144
145 static int ixp4xx_wdt_release(struct inode *inode, struct file *file)
146 {
147         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
148                 wdt_disable();
149         else
150                 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
151                                         "timer will not stop\n");
152         clear_bit(WDT_IN_USE, &wdt_status);
153         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
154
155         return 0;
156 }
157
158
159 static const struct file_operations ixp4xx_wdt_fops = {
160         .owner          = THIS_MODULE,
161         .llseek         = no_llseek,
162         .write          = ixp4xx_wdt_write,
163         .unlocked_ioctl = ixp4xx_wdt_ioctl,
164         .open           = ixp4xx_wdt_open,
165         .release        = ixp4xx_wdt_release,
166 };
167
168 static struct miscdevice ixp4xx_wdt_miscdev = {
169         .minor          = WATCHDOG_MINOR,
170         .name           = "watchdog",
171         .fops           = &ixp4xx_wdt_fops,
172 };
173
174 static int __init ixp4xx_wdt_init(void)
175 {
176         int ret;
177
178         if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
179                 printk(KERN_ERR "IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected"
180                         " - watchdog disabled\n");
181
182                 return -ENODEV;
183         }
184         boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
185                         WDIOF_CARDRESET : 0;
186         ret = misc_register(&ixp4xx_wdt_miscdev);
187         if (ret == 0)
188                 printk(KERN_INFO "IXP4xx Watchdog Timer: heartbeat %d sec\n",
189                         heartbeat);
190         return ret;
191 }
192
193 static void __exit ixp4xx_wdt_exit(void)
194 {
195         misc_deregister(&ixp4xx_wdt_miscdev);
196 }
197
198
199 module_init(ixp4xx_wdt_init);
200 module_exit(ixp4xx_wdt_exit);
201
202 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
203 MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
204
205 module_param(heartbeat, int, 0);
206 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
207
208 module_param(nowayout, int, 0);
209 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
210
211 MODULE_LICENSE("GPL");
212 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
213