]> err.no Git - linux-2.6/blob - drivers/watchdog/ixp4xx_wdt.c
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
[linux-2.6] / 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
26 #include <asm/hardware.h>
27 #include <asm/uaccess.h>
28
29 static int nowayout = WATCHDOG_NOWAYOUT;
30 static int heartbeat = 60;      /* (secs) Default is 1 minute */
31 static unsigned long wdt_status;
32 static unsigned long boot_status;
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
40 wdt_enable(void)
41 {
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 }
48
49 static void
50 wdt_disable(void)
51 {
52         *IXP4XX_OSWK = IXP4XX_WDT_KEY;
53         *IXP4XX_OSWE = 0;
54         *IXP4XX_OSWK = 0;
55 }
56
57 static int
58 ixp4xx_wdt_open(struct inode *inode, struct file *file)
59 {
60         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
61                 return -EBUSY;
62
63         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
64
65         wdt_enable();
66
67         return nonseekable_open(inode, file);
68 }
69
70 static ssize_t
71 ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
72 {
73         if (len) {
74                 if (!nowayout) {
75                         size_t i;
76
77                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
78
79                         for (i = 0; i != len; i++) {
80                                 char c;
81
82                                 if (get_user(c, data + i))
83                                         return -EFAULT;
84                                 if (c == 'V')
85                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
86                         }
87                 }
88                 wdt_enable();
89         }
90
91         return len;
92 }
93
94 static struct watchdog_info ident = {
95         .options        = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
96                           WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
97         .identity       = "IXP4xx Watchdog",
98 };
99
100
101 static int
102 ixp4xx_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
103                         unsigned long arg)
104 {
105         int ret = -ENOTTY;
106         int time;
107
108         switch (cmd) {
109         case WDIOC_GETSUPPORT:
110                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
111                                    sizeof(ident)) ? -EFAULT : 0;
112                 break;
113
114         case WDIOC_GETSTATUS:
115                 ret = put_user(0, (int *)arg);
116                 break;
117
118         case WDIOC_GETBOOTSTATUS:
119                 ret = put_user(boot_status, (int *)arg);
120                 break;
121
122         case WDIOC_SETTIMEOUT:
123                 ret = get_user(time, (int *)arg);
124                 if (ret)
125                         break;
126
127                 if (time <= 0 || time > 60) {
128                         ret = -EINVAL;
129                         break;
130                 }
131
132                 heartbeat = time;
133                 wdt_enable();
134                 /* Fall through */
135
136         case WDIOC_GETTIMEOUT:
137                 ret = put_user(heartbeat, (int *)arg);
138                 break;
139
140         case WDIOC_KEEPALIVE:
141                 wdt_enable();
142                 ret = 0;
143                 break;
144         }
145         return ret;
146 }
147
148 static int
149 ixp4xx_wdt_release(struct inode *inode, struct file *file)
150 {
151         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
152                 wdt_disable();
153         } else {
154                 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
155                                         "timer will not stop\n");
156         }
157
158         clear_bit(WDT_IN_USE, &wdt_status);
159         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
160
161         return 0;
162 }
163
164
165 static const struct file_operations ixp4xx_wdt_fops =
166 {
167         .owner          = THIS_MODULE,
168         .llseek         = no_llseek,
169         .write          = ixp4xx_wdt_write,
170         .ioctl          = ixp4xx_wdt_ioctl,
171         .open           = ixp4xx_wdt_open,
172         .release        = ixp4xx_wdt_release,
173 };
174
175 static struct miscdevice ixp4xx_wdt_miscdev =
176 {
177         .minor          = WATCHDOG_MINOR,
178         .name           = "watchdog",
179         .fops           = &ixp4xx_wdt_fops,
180 };
181
182 static int __init ixp4xx_wdt_init(void)
183 {
184         int ret;
185         unsigned long processor_id;
186
187         asm("mrc p15, 0, %0, cr0, cr0, 0;" : "=r"(processor_id) :);
188         if (!(processor_id & 0xf) && !cpu_is_ixp46x()) {
189                 printk("IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected - "
190                         "watchdog disabled\n");
191
192                 return -ENODEV;
193         }
194
195         ret = misc_register(&ixp4xx_wdt_miscdev);
196         if (ret == 0)
197                 printk("IXP4xx Watchdog Timer: heartbeat %d sec\n", heartbeat);
198
199         boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
200                         WDIOF_CARDRESET : 0;
201
202         return ret;
203 }
204
205 static void __exit ixp4xx_wdt_exit(void)
206 {
207         misc_deregister(&ixp4xx_wdt_miscdev);
208 }
209
210
211 module_init(ixp4xx_wdt_init);
212 module_exit(ixp4xx_wdt_exit);
213
214 MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
215 MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
216
217 module_param(heartbeat, int, 0);
218 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
219
220 module_param(nowayout, int, 0);
221 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
222
223 MODULE_LICENSE("GPL");
224 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
225