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1da177e4 LT |
1 | /* |
2 | * Intel 21285 watchdog driver | |
3 | * Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998 | |
4 | * | |
5 | * based on | |
6 | * | |
7 | * SoftDog 0.05: A Software Watchdog Device | |
8 | * | |
9 | * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. | |
10 | * | |
11 | * This program is free software; you can redistribute it and/or | |
12 | * modify it under the terms of the GNU General Public License | |
13 | * as published by the Free Software Foundation; either version | |
14 | * 2 of the License, or (at your option) any later version. | |
15 | * | |
16 | */ | |
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/mm.h> | |
24 | #include <linux/miscdevice.h> | |
25 | #include <linux/watchdog.h> | |
26 | #include <linux/reboot.h> | |
27 | #include <linux/init.h> | |
28 | #include <linux/interrupt.h> | |
29 | ||
30 | #include <asm/irq.h> | |
31 | #include <asm/uaccess.h> | |
32 | #include <asm/hardware.h> | |
33 | #include <asm/mach-types.h> | |
34 | #include <asm/hardware/dec21285.h> | |
35 | ||
36 | /* | |
37 | * Define this to stop the watchdog actually rebooting the machine. | |
38 | */ | |
39 | #undef ONLY_TESTING | |
40 | ||
41 | static unsigned int soft_margin = 60; /* in seconds */ | |
42 | static unsigned int reload; | |
43 | static unsigned long timer_alive; | |
44 | ||
45 | #ifdef ONLY_TESTING | |
46 | /* | |
47 | * If the timer expires.. | |
48 | */ | |
7d12e780 | 49 | static void watchdog_fire(int irq, void *dev_id) |
1da177e4 LT |
50 | { |
51 | printk(KERN_CRIT "Watchdog: Would Reboot.\n"); | |
52 | *CSR_TIMER4_CNTL = 0; | |
53 | *CSR_TIMER4_CLR = 0; | |
54 | } | |
55 | #endif | |
56 | ||
57 | /* | |
58 | * Refresh the timer. | |
59 | */ | |
60 | static void watchdog_ping(void) | |
61 | { | |
62 | *CSR_TIMER4_LOAD = reload; | |
63 | } | |
64 | ||
65 | /* | |
66 | * Allow only one person to hold it open | |
67 | */ | |
68 | static int watchdog_open(struct inode *inode, struct file *file) | |
69 | { | |
70 | int ret; | |
71 | ||
72 | if (*CSR_SA110_CNTL & (1 << 13)) | |
73 | return -EBUSY; | |
74 | ||
75 | if (test_and_set_bit(1, &timer_alive)) | |
76 | return -EBUSY; | |
77 | ||
78 | reload = soft_margin * (mem_fclk_21285 / 256); | |
79 | ||
80 | *CSR_TIMER4_CLR = 0; | |
81 | watchdog_ping(); | |
82 | *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD | |
83 | | TIMER_CNTL_DIV256; | |
84 | ||
85 | #ifdef ONLY_TESTING | |
86 | ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL); | |
87 | if (ret) { | |
88 | *CSR_TIMER4_CNTL = 0; | |
89 | clear_bit(1, &timer_alive); | |
90 | } | |
91 | #else | |
92 | /* | |
93 | * Setting this bit is irreversible; once enabled, there is | |
94 | * no way to disable the watchdog. | |
95 | */ | |
96 | *CSR_SA110_CNTL |= 1 << 13; | |
97 | ||
98 | ret = 0; | |
99 | #endif | |
100 | nonseekable_open(inode, file); | |
101 | return ret; | |
102 | } | |
103 | ||
104 | /* | |
105 | * Shut off the timer. | |
106 | * Note: if we really have enabled the watchdog, there | |
107 | * is no way to turn off. | |
108 | */ | |
109 | static int watchdog_release(struct inode *inode, struct file *file) | |
110 | { | |
111 | #ifdef ONLY_TESTING | |
112 | free_irq(IRQ_TIMER4, NULL); | |
113 | clear_bit(1, &timer_alive); | |
114 | #endif | |
115 | return 0; | |
116 | } | |
117 | ||
118 | static ssize_t | |
119 | watchdog_write(struct file *file, const char *data, size_t len, loff_t *ppos) | |
120 | { | |
121 | /* | |
122 | * Refresh the timer. | |
123 | */ | |
124 | if (len) | |
125 | watchdog_ping(); | |
126 | ||
127 | return len; | |
128 | } | |
129 | ||
130 | static struct watchdog_info ident = { | |
131 | .options = WDIOF_SETTIMEOUT, | |
132 | .identity = "Footbridge Watchdog", | |
133 | }; | |
134 | ||
135 | static int | |
136 | watchdog_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | |
137 | unsigned long arg) | |
138 | { | |
139 | unsigned int new_margin; | |
795b89d2 | 140 | int ret = -ENOTTY; |
1da177e4 LT |
141 | |
142 | switch(cmd) { | |
143 | case WDIOC_GETSUPPORT: | |
144 | ret = 0; | |
145 | if (copy_to_user((void *)arg, &ident, sizeof(ident))) | |
146 | ret = -EFAULT; | |
147 | break; | |
148 | ||
149 | case WDIOC_GETSTATUS: | |
150 | case WDIOC_GETBOOTSTATUS: | |
151 | ret = put_user(0,(int *)arg); | |
152 | break; | |
153 | ||
154 | case WDIOC_KEEPALIVE: | |
155 | watchdog_ping(); | |
156 | ret = 0; | |
157 | break; | |
158 | ||
159 | case WDIOC_SETTIMEOUT: | |
160 | ret = get_user(new_margin, (int *)arg); | |
161 | if (ret) | |
162 | break; | |
163 | ||
164 | /* Arbitrary, can't find the card's limits */ | |
165 | if (new_margin < 0 || new_margin > 60) { | |
166 | ret = -EINVAL; | |
167 | break; | |
168 | } | |
169 | ||
170 | soft_margin = new_margin; | |
171 | reload = soft_margin * (mem_fclk_21285 / 256); | |
172 | watchdog_ping(); | |
173 | /* Fall */ | |
174 | case WDIOC_GETTIMEOUT: | |
175 | ret = put_user(soft_margin, (int *)arg); | |
176 | break; | |
177 | } | |
178 | return ret; | |
179 | } | |
180 | ||
62322d25 | 181 | static const struct file_operations watchdog_fops = { |
1da177e4 LT |
182 | .owner = THIS_MODULE, |
183 | .llseek = no_llseek, | |
184 | .write = watchdog_write, | |
185 | .ioctl = watchdog_ioctl, | |
186 | .open = watchdog_open, | |
187 | .release = watchdog_release, | |
188 | }; | |
189 | ||
190 | static struct miscdevice watchdog_miscdev = { | |
191 | .minor = WATCHDOG_MINOR, | |
192 | .name = "watchdog", | |
193 | .fops = &watchdog_fops, | |
194 | }; | |
195 | ||
196 | static int __init footbridge_watchdog_init(void) | |
197 | { | |
198 | int retval; | |
199 | ||
200 | if (machine_is_netwinder()) | |
201 | return -ENODEV; | |
202 | ||
203 | retval = misc_register(&watchdog_miscdev); | |
204 | if (retval < 0) | |
205 | return retval; | |
206 | ||
207 | printk("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n", | |
208 | soft_margin); | |
209 | ||
210 | if (machine_is_cats()) | |
211 | printk("Warning: Watchdog reset may not work on this machine.\n"); | |
212 | return 0; | |
213 | } | |
214 | ||
215 | static void __exit footbridge_watchdog_exit(void) | |
216 | { | |
217 | misc_deregister(&watchdog_miscdev); | |
218 | } | |
219 | ||
220 | MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>"); | |
221 | MODULE_DESCRIPTION("Footbridge watchdog driver"); | |
222 | MODULE_LICENSE("GPL"); | |
223 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
224 | ||
225 | module_param(soft_margin, int, 0); | |
226 | MODULE_PARM_DESC(soft_margin,"Watchdog timeout in seconds"); | |
227 | ||
228 | module_init(footbridge_watchdog_init); | |
229 | module_exit(footbridge_watchdog_exit); |