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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@lxorguk.ukuu.org.uk>, |
10 | * All Rights Reserved. |
11 | * |
12 | * This program is free software; you can redistribute it and/or |
13 | * modify it under the terms of the GNU General Public License |
14 | * as published by the Free Software Foundation; either version |
15 | * 2 of the License, or (at your option) any later version. |
16 | * |
17 | */ |
18 | |
19 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
20 | |
21 | #include <linux/module.h> |
22 | #include <linux/moduleparam.h> |
23 | #include <linux/types.h> |
24 | #include <linux/kernel.h> |
25 | #include <linux/fs.h> |
26 | #include <linux/mm.h> |
27 | #include <linux/miscdevice.h> |
28 | #include <linux/watchdog.h> |
29 | #include <linux/reboot.h> |
30 | #include <linux/init.h> |
31 | #include <linux/interrupt.h> |
32 | #include <linux/uaccess.h> |
33 | #include <linux/irq.h> |
34 | #include <mach/hardware.h> |
35 | |
36 | #include <asm/mach-types.h> |
37 | #include <asm/system_info.h> |
38 | #include <asm/hardware/dec21285.h> |
39 | |
40 | /* |
41 | * Define this to stop the watchdog actually rebooting the machine. |
42 | */ |
43 | #undef ONLY_TESTING |
44 | |
45 | static unsigned int soft_margin = 60; /* in seconds */ |
46 | static unsigned int reload; |
47 | static unsigned long timer_alive; |
48 | |
49 | #ifdef ONLY_TESTING |
50 | /* |
51 | * If the timer expires.. |
52 | */ |
53 | static void watchdog_fire(int irq, void *dev_id) |
54 | { |
55 | pr_crit("Would Reboot\n"); |
56 | *CSR_TIMER4_CNTL = 0; |
57 | *CSR_TIMER4_CLR = 0; |
58 | } |
59 | #endif |
60 | |
61 | /* |
62 | * Refresh the timer. |
63 | */ |
64 | static void watchdog_ping(void) |
65 | { |
66 | *CSR_TIMER4_LOAD = reload; |
67 | } |
68 | |
69 | /* |
70 | * Allow only one person to hold it open |
71 | */ |
72 | static int watchdog_open(struct inode *inode, struct file *file) |
73 | { |
74 | int ret; |
75 | |
76 | if (*CSR_SA110_CNTL & (1 << 13)) |
77 | return -EBUSY; |
78 | |
79 | if (test_and_set_bit(1, &timer_alive)) |
80 | return -EBUSY; |
81 | |
82 | reload = soft_margin * (mem_fclk_21285 / 256); |
83 | |
84 | *CSR_TIMER4_CLR = 0; |
85 | watchdog_ping(); |
86 | *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD |
87 | | TIMER_CNTL_DIV256; |
88 | |
89 | #ifdef ONLY_TESTING |
90 | ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL); |
91 | if (ret) { |
92 | *CSR_TIMER4_CNTL = 0; |
93 | clear_bit(1, &timer_alive); |
94 | } |
95 | #else |
96 | /* |
97 | * Setting this bit is irreversible; once enabled, there is |
98 | * no way to disable the watchdog. |
99 | */ |
100 | *CSR_SA110_CNTL |= 1 << 13; |
101 | |
102 | ret = 0; |
103 | #endif |
104 | nonseekable_open(inode, file); |
105 | return ret; |
106 | } |
107 | |
108 | /* |
109 | * Shut off the timer. |
110 | * Note: if we really have enabled the watchdog, there |
111 | * is no way to turn off. |
112 | */ |
113 | static int watchdog_release(struct inode *inode, struct file *file) |
114 | { |
115 | #ifdef ONLY_TESTING |
116 | free_irq(IRQ_TIMER4, NULL); |
117 | clear_bit(1, &timer_alive); |
118 | #endif |
119 | return 0; |
120 | } |
121 | |
122 | static ssize_t watchdog_write(struct file *file, const char __user *data, |
123 | size_t len, loff_t *ppos) |
124 | { |
125 | /* |
126 | * Refresh the timer. |
127 | */ |
128 | if (len) |
129 | watchdog_ping(); |
130 | |
131 | return len; |
132 | } |
133 | |
134 | static const struct watchdog_info ident = { |
135 | .options = WDIOF_SETTIMEOUT, |
136 | .identity = "Footbridge Watchdog", |
137 | }; |
138 | |
139 | static long watchdog_ioctl(struct file *file, unsigned int cmd, |
140 | unsigned long arg) |
141 | { |
142 | unsigned int new_margin; |
143 | int __user *int_arg = (int __user *)arg; |
144 | int ret = -ENOTTY; |
145 | |
146 | switch (cmd) { |
147 | case WDIOC_GETSUPPORT: |
148 | ret = 0; |
149 | if (copy_to_user((void __user *)arg, &ident, sizeof(ident))) |
150 | ret = -EFAULT; |
151 | break; |
152 | |
153 | case WDIOC_GETSTATUS: |
154 | case WDIOC_GETBOOTSTATUS: |
155 | ret = put_user(0, int_arg); |
156 | break; |
157 | |
158 | case WDIOC_KEEPALIVE: |
159 | watchdog_ping(); |
160 | ret = 0; |
161 | break; |
162 | |
163 | case WDIOC_SETTIMEOUT: |
164 | ret = get_user(new_margin, int_arg); |
165 | if (ret) |
166 | break; |
167 | |
168 | /* Arbitrary, can't find the card's limits */ |
169 | if (new_margin < 0 || new_margin > 60) { |
170 | ret = -EINVAL; |
171 | break; |
172 | } |
173 | |
174 | soft_margin = new_margin; |
175 | reload = soft_margin * (mem_fclk_21285 / 256); |
176 | watchdog_ping(); |
177 | /* Fall */ |
178 | case WDIOC_GETTIMEOUT: |
179 | ret = put_user(soft_margin, int_arg); |
180 | break; |
181 | } |
182 | return ret; |
183 | } |
184 | |
185 | static const struct file_operations watchdog_fops = { |
186 | .owner = THIS_MODULE, |
187 | .llseek = no_llseek, |
188 | .write = watchdog_write, |
189 | .unlocked_ioctl = watchdog_ioctl, |
190 | .open = watchdog_open, |
191 | .release = watchdog_release, |
192 | }; |
193 | |
194 | static struct miscdevice watchdog_miscdev = { |
195 | .minor = WATCHDOG_MINOR, |
196 | .name = "watchdog", |
197 | .fops = &watchdog_fops, |
198 | }; |
199 | |
200 | static int __init footbridge_watchdog_init(void) |
201 | { |
202 | int retval; |
203 | |
204 | if (machine_is_netwinder()) |
205 | return -ENODEV; |
206 | |
207 | retval = misc_register(&watchdog_miscdev); |
208 | if (retval < 0) |
209 | return retval; |
210 | |
211 | pr_info("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n", |
212 | soft_margin); |
213 | |
214 | if (machine_is_cats()) |
215 | pr_warn("Warning: Watchdog reset may not work on this machine\n"); |
216 | return 0; |
217 | } |
218 | |
219 | static void __exit footbridge_watchdog_exit(void) |
220 | { |
221 | misc_deregister(&watchdog_miscdev); |
222 | } |
223 | |
224 | MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>"); |
225 | MODULE_DESCRIPTION("Footbridge watchdog driver"); |
226 | MODULE_LICENSE("GPL"); |
227 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
228 | |
229 | module_param(soft_margin, int, 0); |
230 | MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds"); |
231 | |
232 | module_init(footbridge_watchdog_init); |
233 | module_exit(footbridge_watchdog_exit); |
234 |
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