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1/* drivers/char/watchdog/scx200_wdt.c
2
3 National Semiconductor SCx200 Watchdog support
4
5 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
6
7 Some code taken from:
8 National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
9 (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>
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 as
13 published by the Free Software Foundation; either version 2 of the
14 License, or (at your option) any later version.
15
16 The author(s) of this software shall not be held liable for damages
17 of any nature resulting due to the use of this software. This
18 software is provided AS-IS with no warranties. */
19
20#include <linux/module.h>
21#include <linux/moduleparam.h>
22#include <linux/init.h>
23#include <linux/miscdevice.h>
24#include <linux/watchdog.h>
25#include <linux/notifier.h>
26#include <linux/reboot.h>
27#include <linux/fs.h>
28#include <linux/ioport.h>
29#include <linux/scx200.h>
30#include <linux/uaccess.h>
31#include <linux/io.h>
32
33#define NAME "scx200_wdt"
34
35MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
36MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
37MODULE_LICENSE("GPL");
38MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
39
40static int margin = 60; /* in seconds */
41module_param(margin, int, 0);
42MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
43
44static int nowayout = WATCHDOG_NOWAYOUT;
45module_param(nowayout, int, 0);
46MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
47
48static u16 wdto_restart;
49static char expect_close;
50static unsigned long open_lock;
51static DEFINE_SPINLOCK(scx_lock);
52
53/* Bits of the WDCNFG register */
54#define W_ENABLE 0x00fa /* Enable watchdog */
55#define W_DISABLE 0x0000 /* Disable watchdog */
56
57/* The scaling factor for the timer, this depends on the value of W_ENABLE */
58#define W_SCALE (32768/1024)
59
60static void scx200_wdt_ping(void)
61{
62 spin_lock(&scx_lock);
63 outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
64 spin_unlock(&scx_lock);
65}
66
67static void scx200_wdt_update_margin(void)
68{
69 printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
70 wdto_restart = margin * W_SCALE;
71}
72
73static void scx200_wdt_enable(void)
74{
75 printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n",
76 wdto_restart);
77
78 spin_lock(&scx_lock);
79 outw(0, scx200_cb_base + SCx200_WDT_WDTO);
80 outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
81 outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
82 spin_unlock(&scx_lock);
83
84 scx200_wdt_ping();
85}
86
87static void scx200_wdt_disable(void)
88{
89 printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
90
91 spin_lock(&scx_lock);
92 outw(0, scx200_cb_base + SCx200_WDT_WDTO);
93 outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
94 outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
95 spin_unlock(&scx_lock);
96}
97
98static int scx200_wdt_open(struct inode *inode, struct file *file)
99{
100 /* only allow one at a time */
101 if (test_and_set_bit(0, &open_lock))
102 return -EBUSY;
103 scx200_wdt_enable();
104
105 return nonseekable_open(inode, file);
106}
107
108static int scx200_wdt_release(struct inode *inode, struct file *file)
109{
110 if (expect_close != 42)
111 printk(KERN_WARNING NAME
112 ": watchdog device closed unexpectedly, "
113 "will not disable the watchdog timer\n");
114 else if (!nowayout)
115 scx200_wdt_disable();
116 expect_close = 0;
117 clear_bit(0, &open_lock);
118
119 return 0;
120}
121
122static int scx200_wdt_notify_sys(struct notifier_block *this,
123 unsigned long code, void *unused)
124{
125 if (code == SYS_HALT || code == SYS_POWER_OFF)
126 if (!nowayout)
127 scx200_wdt_disable();
128
129 return NOTIFY_DONE;
130}
131
132static struct notifier_block scx200_wdt_notifier = {
133 .notifier_call = scx200_wdt_notify_sys,
134};
135
136static ssize_t scx200_wdt_write(struct file *file, const char __user *data,
137 size_t len, loff_t *ppos)
138{
139 /* check for a magic close character */
140 if (len) {
141 size_t i;
142
143 scx200_wdt_ping();
144
145 expect_close = 0;
146 for (i = 0; i < len; ++i) {
147 char c;
148 if (get_user(c, data + i))
149 return -EFAULT;
150 if (c == 'V')
151 expect_close = 42;
152 }
153
154 return len;
155 }
156
157 return 0;
158}
159
160static long scx200_wdt_ioctl(struct file *file, unsigned int cmd,
161 unsigned long arg)
162{
163 void __user *argp = (void __user *)arg;
164 int __user *p = argp;
165 static const struct watchdog_info ident = {
166 .identity = "NatSemi SCx200 Watchdog",
167 .firmware_version = 1,
168 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
169 WDIOF_MAGICCLOSE,
170 };
171 int new_margin;
172
173 switch (cmd) {
174 case WDIOC_GETSUPPORT:
175 if (copy_to_user(argp, &ident, sizeof(ident)))
176 return -EFAULT;
177 return 0;
178 case WDIOC_GETSTATUS:
179 case WDIOC_GETBOOTSTATUS:
180 if (put_user(0, p))
181 return -EFAULT;
182 return 0;
183 case WDIOC_KEEPALIVE:
184 scx200_wdt_ping();
185 return 0;
186 case WDIOC_SETTIMEOUT:
187 if (get_user(new_margin, p))
188 return -EFAULT;
189 if (new_margin < 1)
190 return -EINVAL;
191 margin = new_margin;
192 scx200_wdt_update_margin();
193 scx200_wdt_ping();
194 case WDIOC_GETTIMEOUT:
195 if (put_user(margin, p))
196 return -EFAULT;
197 return 0;
198 default:
199 return -ENOTTY;
200 }
201}
202
203static const struct file_operations scx200_wdt_fops = {
204 .owner = THIS_MODULE,
205 .llseek = no_llseek,
206 .write = scx200_wdt_write,
207 .unlocked_ioctl = scx200_wdt_ioctl,
208 .open = scx200_wdt_open,
209 .release = scx200_wdt_release,
210};
211
212static struct miscdevice scx200_wdt_miscdev = {
213 .minor = WATCHDOG_MINOR,
214 .name = "watchdog",
215 .fops = &scx200_wdt_fops,
216};
217
218static int __init scx200_wdt_init(void)
219{
220 int r;
221
222 printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n");
223
224 /* check that we have found the configuration block */
225 if (!scx200_cb_present())
226 return -ENODEV;
227
228 if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
229 SCx200_WDT_SIZE,
230 "NatSemi SCx200 Watchdog")) {
231 printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
232 return -EBUSY;
233 }
234
235 scx200_wdt_update_margin();
236 scx200_wdt_disable();
237
238 r = register_reboot_notifier(&scx200_wdt_notifier);
239 if (r) {
240 printk(KERN_ERR NAME ": unable to register reboot notifier");
241 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
242 SCx200_WDT_SIZE);
243 return r;
244 }
245
246 r = misc_register(&scx200_wdt_miscdev);
247 if (r) {
248 unregister_reboot_notifier(&scx200_wdt_notifier);
249 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
250 SCx200_WDT_SIZE);
251 return r;
252 }
253
254 return 0;
255}
256
257static void __exit scx200_wdt_cleanup(void)
258{
259 misc_deregister(&scx200_wdt_miscdev);
260 unregister_reboot_notifier(&scx200_wdt_notifier);
261 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
262 SCx200_WDT_SIZE);
263}
264
265module_init(scx200_wdt_init);
266module_exit(scx200_wdt_cleanup);
267
268/*
269 Local variables:
270 compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
271 c-basic-offset: 8
272 End:
273*/
1/* drivers/char/watchdog/scx200_wdt.c
2
3 National Semiconductor SCx200 Watchdog support
4
5 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
6
7 Some code taken from:
8 National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
9 (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>
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 as
13 published by the Free Software Foundation; either version 2 of the
14 License, or (at your option) any later version.
15
16 The author(s) of this software shall not be held liable for damages
17 of any nature resulting due to the use of this software. This
18 software is provided AS-IS with no warranties. */
19
20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22#include <linux/module.h>
23#include <linux/moduleparam.h>
24#include <linux/init.h>
25#include <linux/miscdevice.h>
26#include <linux/watchdog.h>
27#include <linux/notifier.h>
28#include <linux/reboot.h>
29#include <linux/fs.h>
30#include <linux/ioport.h>
31#include <linux/scx200.h>
32#include <linux/uaccess.h>
33#include <linux/io.h>
34
35#define DEBUG
36
37MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
38MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
39MODULE_LICENSE("GPL");
40
41static int margin = 60; /* in seconds */
42module_param(margin, int, 0);
43MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
44
45static bool nowayout = WATCHDOG_NOWAYOUT;
46module_param(nowayout, bool, 0);
47MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
48
49static u16 wdto_restart;
50static char expect_close;
51static unsigned long open_lock;
52static DEFINE_SPINLOCK(scx_lock);
53
54/* Bits of the WDCNFG register */
55#define W_ENABLE 0x00fa /* Enable watchdog */
56#define W_DISABLE 0x0000 /* Disable watchdog */
57
58/* The scaling factor for the timer, this depends on the value of W_ENABLE */
59#define W_SCALE (32768/1024)
60
61static void scx200_wdt_ping(void)
62{
63 spin_lock(&scx_lock);
64 outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
65 spin_unlock(&scx_lock);
66}
67
68static void scx200_wdt_update_margin(void)
69{
70 pr_info("timer margin %d seconds\n", margin);
71 wdto_restart = margin * W_SCALE;
72}
73
74static void scx200_wdt_enable(void)
75{
76 pr_debug("enabling watchdog timer, wdto_restart = %d\n", wdto_restart);
77
78 spin_lock(&scx_lock);
79 outw(0, scx200_cb_base + SCx200_WDT_WDTO);
80 outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
81 outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
82 spin_unlock(&scx_lock);
83
84 scx200_wdt_ping();
85}
86
87static void scx200_wdt_disable(void)
88{
89 pr_debug("disabling watchdog timer\n");
90
91 spin_lock(&scx_lock);
92 outw(0, scx200_cb_base + SCx200_WDT_WDTO);
93 outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
94 outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
95 spin_unlock(&scx_lock);
96}
97
98static int scx200_wdt_open(struct inode *inode, struct file *file)
99{
100 /* only allow one at a time */
101 if (test_and_set_bit(0, &open_lock))
102 return -EBUSY;
103 scx200_wdt_enable();
104
105 return nonseekable_open(inode, file);
106}
107
108static int scx200_wdt_release(struct inode *inode, struct file *file)
109{
110 if (expect_close != 42)
111 pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
112 else if (!nowayout)
113 scx200_wdt_disable();
114 expect_close = 0;
115 clear_bit(0, &open_lock);
116
117 return 0;
118}
119
120static int scx200_wdt_notify_sys(struct notifier_block *this,
121 unsigned long code, void *unused)
122{
123 if (code == SYS_HALT || code == SYS_POWER_OFF)
124 if (!nowayout)
125 scx200_wdt_disable();
126
127 return NOTIFY_DONE;
128}
129
130static struct notifier_block scx200_wdt_notifier = {
131 .notifier_call = scx200_wdt_notify_sys,
132};
133
134static ssize_t scx200_wdt_write(struct file *file, const char __user *data,
135 size_t len, loff_t *ppos)
136{
137 /* check for a magic close character */
138 if (len) {
139 size_t i;
140
141 scx200_wdt_ping();
142
143 expect_close = 0;
144 for (i = 0; i < len; ++i) {
145 char c;
146 if (get_user(c, data + i))
147 return -EFAULT;
148 if (c == 'V')
149 expect_close = 42;
150 }
151
152 return len;
153 }
154
155 return 0;
156}
157
158static long scx200_wdt_ioctl(struct file *file, unsigned int cmd,
159 unsigned long arg)
160{
161 void __user *argp = (void __user *)arg;
162 int __user *p = argp;
163 static const struct watchdog_info ident = {
164 .identity = "NatSemi SCx200 Watchdog",
165 .firmware_version = 1,
166 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
167 WDIOF_MAGICCLOSE,
168 };
169 int new_margin;
170
171 switch (cmd) {
172 case WDIOC_GETSUPPORT:
173 if (copy_to_user(argp, &ident, sizeof(ident)))
174 return -EFAULT;
175 return 0;
176 case WDIOC_GETSTATUS:
177 case WDIOC_GETBOOTSTATUS:
178 if (put_user(0, p))
179 return -EFAULT;
180 return 0;
181 case WDIOC_KEEPALIVE:
182 scx200_wdt_ping();
183 return 0;
184 case WDIOC_SETTIMEOUT:
185 if (get_user(new_margin, p))
186 return -EFAULT;
187 if (new_margin < 1)
188 return -EINVAL;
189 margin = new_margin;
190 scx200_wdt_update_margin();
191 scx200_wdt_ping();
192 case WDIOC_GETTIMEOUT:
193 if (put_user(margin, p))
194 return -EFAULT;
195 return 0;
196 default:
197 return -ENOTTY;
198 }
199}
200
201static const struct file_operations scx200_wdt_fops = {
202 .owner = THIS_MODULE,
203 .llseek = no_llseek,
204 .write = scx200_wdt_write,
205 .unlocked_ioctl = scx200_wdt_ioctl,
206 .open = scx200_wdt_open,
207 .release = scx200_wdt_release,
208};
209
210static struct miscdevice scx200_wdt_miscdev = {
211 .minor = WATCHDOG_MINOR,
212 .name = "watchdog",
213 .fops = &scx200_wdt_fops,
214};
215
216static int __init scx200_wdt_init(void)
217{
218 int r;
219
220 pr_debug("NatSemi SCx200 Watchdog Driver\n");
221
222 /* check that we have found the configuration block */
223 if (!scx200_cb_present())
224 return -ENODEV;
225
226 if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
227 SCx200_WDT_SIZE,
228 "NatSemi SCx200 Watchdog")) {
229 pr_warn("watchdog I/O region busy\n");
230 return -EBUSY;
231 }
232
233 scx200_wdt_update_margin();
234 scx200_wdt_disable();
235
236 r = register_reboot_notifier(&scx200_wdt_notifier);
237 if (r) {
238 pr_err("unable to register reboot notifier\n");
239 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
240 SCx200_WDT_SIZE);
241 return r;
242 }
243
244 r = misc_register(&scx200_wdt_miscdev);
245 if (r) {
246 unregister_reboot_notifier(&scx200_wdt_notifier);
247 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
248 SCx200_WDT_SIZE);
249 return r;
250 }
251
252 return 0;
253}
254
255static void __exit scx200_wdt_cleanup(void)
256{
257 misc_deregister(&scx200_wdt_miscdev);
258 unregister_reboot_notifier(&scx200_wdt_notifier);
259 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
260 SCx200_WDT_SIZE);
261}
262
263module_init(scx200_wdt_init);
264module_exit(scx200_wdt_cleanup);
265
266/*
267 Local variables:
268 compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
269 c-basic-offset: 8
270 End:
271*/