watchdog: nowayout is bool
[linux-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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/types.h>
21 #include <linux/kernel.h>
22 #include <linux/fs.h>
23 #include <linux/miscdevice.h>
24 #include <linux/watchdog.h>
25 #include <linux/init.h>
26 #include <linux/bitops.h>
27 #include <linux/uaccess.h>
28 #include <mach/hardware.h>
29
30 static bool nowayout = WATCHDOG_NOWAYOUT;
31 static int heartbeat = 60;      /* (secs) Default is 1 minute */
32 static unsigned long wdt_status;
33 static unsigned long boot_status;
34 static DEFINE_SPINLOCK(wdt_lock);
35
36 #define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
37
38 #define WDT_IN_USE              0
39 #define WDT_OK_TO_CLOSE         1
40
41 static void wdt_enable(void)
42 {
43         spin_lock(&wdt_lock);
44         *IXP4XX_OSWK = IXP4XX_WDT_KEY;
45         *IXP4XX_OSWE = 0;
46         *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
47         *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
48         *IXP4XX_OSWK = 0;
49         spin_unlock(&wdt_lock);
50 }
51
52 static void wdt_disable(void)
53 {
54         spin_lock(&wdt_lock);
55         *IXP4XX_OSWK = IXP4XX_WDT_KEY;
56         *IXP4XX_OSWE = 0;
57         *IXP4XX_OSWK = 0;
58         spin_unlock(&wdt_lock);
59 }
60
61 static int ixp4xx_wdt_open(struct inode *inode, struct file *file)
62 {
63         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
64                 return -EBUSY;
65
66         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
67         wdt_enable();
68         return nonseekable_open(inode, file);
69 }
70
71 static ssize_t
72 ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
73 {
74         if (len) {
75                 if (!nowayout) {
76                         size_t i;
77
78                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
79
80                         for (i = 0; i != len; i++) {
81                                 char c;
82
83                                 if (get_user(c, data + i))
84                                         return -EFAULT;
85                                 if (c == 'V')
86                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
87                         }
88                 }
89                 wdt_enable();
90         }
91         return len;
92 }
93
94 static const struct watchdog_info ident = {
95         .options        = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
96                           WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
97         .identity       = "IXP4xx Watchdog",
98 };
99
100
101 static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
102                                                         unsigned long arg)
103 {
104         int ret = -ENOTTY;
105         int time;
106
107         switch (cmd) {
108         case WDIOC_GETSUPPORT:
109                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
110                                    sizeof(ident)) ? -EFAULT : 0;
111                 break;
112
113         case WDIOC_GETSTATUS:
114                 ret = put_user(0, (int *)arg);
115                 break;
116
117         case WDIOC_GETBOOTSTATUS:
118                 ret = put_user(boot_status, (int *)arg);
119                 break;
120
121         case WDIOC_KEEPALIVE:
122                 wdt_enable();
123                 ret = 0;
124                 break;
125
126         case WDIOC_SETTIMEOUT:
127                 ret = get_user(time, (int *)arg);
128                 if (ret)
129                         break;
130
131                 if (time <= 0 || time > 60) {
132                         ret = -EINVAL;
133                         break;
134                 }
135
136                 heartbeat = time;
137                 wdt_enable();
138                 /* Fall through */
139
140         case WDIOC_GETTIMEOUT:
141                 ret = put_user(heartbeat, (int *)arg);
142                 break;
143         }
144         return ret;
145 }
146
147 static int ixp4xx_wdt_release(struct inode *inode, struct file *file)
148 {
149         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
150                 wdt_disable();
151         else
152                 pr_crit("Device closed unexpectedly - timer will not stop\n");
153         clear_bit(WDT_IN_USE, &wdt_status);
154         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
155
156         return 0;
157 }
158
159
160 static const struct file_operations ixp4xx_wdt_fops = {
161         .owner          = THIS_MODULE,
162         .llseek         = no_llseek,
163         .write          = ixp4xx_wdt_write,
164         .unlocked_ioctl = ixp4xx_wdt_ioctl,
165         .open           = ixp4xx_wdt_open,
166         .release        = ixp4xx_wdt_release,
167 };
168
169 static struct miscdevice ixp4xx_wdt_miscdev = {
170         .minor          = WATCHDOG_MINOR,
171         .name           = "watchdog",
172         .fops           = &ixp4xx_wdt_fops,
173 };
174
175 static int __init ixp4xx_wdt_init(void)
176 {
177         int ret;
178
179         if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
180                 pr_err("Rev. A0 IXP42x CPU detected - 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                 pr_info("timer heartbeat %d sec\n", heartbeat);
189         return ret;
190 }
191
192 static void __exit ixp4xx_wdt_exit(void)
193 {
194         misc_deregister(&ixp4xx_wdt_miscdev);
195 }
196
197
198 module_init(ixp4xx_wdt_init);
199 module_exit(ixp4xx_wdt_exit);
200
201 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
202 MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
203
204 module_param(heartbeat, int, 0);
205 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
206
207 module_param(nowayout, bool, 0);
208 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
209
210 MODULE_LICENSE("GPL");
211 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
212