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1da177e4 LT |
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 | ||
27c766aa JP |
20 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
21 | ||
1da177e4 LT |
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> | |
6473d160 | 30 | #include <linux/ioport.h> |
1da177e4 | 31 | #include <linux/scx200.h> |
9b748ed0 AC |
32 | #include <linux/uaccess.h> |
33 | #include <linux/io.h> | |
1da177e4 | 34 | |
27c766aa | 35 | #define DEBUG |
1da177e4 LT |
36 | |
37 | MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); | |
38 | MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver"); | |
39 | MODULE_LICENSE("GPL"); | |
40 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
41 | ||
1da177e4 LT |
42 | static int margin = 60; /* in seconds */ |
43 | module_param(margin, int, 0); | |
44 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds"); | |
45 | ||
86a1e189 WVS |
46 | static bool nowayout = WATCHDOG_NOWAYOUT; |
47 | module_param(nowayout, bool, 0); | |
1da177e4 LT |
48 | MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); |
49 | ||
50 | static u16 wdto_restart; | |
1da177e4 | 51 | static char expect_close; |
9b748ed0 AC |
52 | static unsigned long open_lock; |
53 | static DEFINE_SPINLOCK(scx_lock); | |
1da177e4 LT |
54 | |
55 | /* Bits of the WDCNFG register */ | |
56 | #define W_ENABLE 0x00fa /* Enable watchdog */ | |
57 | #define W_DISABLE 0x0000 /* Disable watchdog */ | |
58 | ||
59 | /* The scaling factor for the timer, this depends on the value of W_ENABLE */ | |
60 | #define W_SCALE (32768/1024) | |
61 | ||
62 | static void scx200_wdt_ping(void) | |
63 | { | |
9b748ed0 | 64 | spin_lock(&scx_lock); |
1da177e4 | 65 | outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO); |
9b748ed0 | 66 | spin_unlock(&scx_lock); |
1da177e4 LT |
67 | } |
68 | ||
69 | static void scx200_wdt_update_margin(void) | |
70 | { | |
27c766aa | 71 | pr_info("timer margin %d seconds\n", margin); |
1da177e4 LT |
72 | wdto_restart = margin * W_SCALE; |
73 | } | |
74 | ||
75 | static void scx200_wdt_enable(void) | |
76 | { | |
27c766aa | 77 | pr_debug("enabling watchdog timer, wdto_restart = %d\n", wdto_restart); |
1da177e4 | 78 | |
9b748ed0 | 79 | spin_lock(&scx_lock); |
1da177e4 LT |
80 | outw(0, scx200_cb_base + SCx200_WDT_WDTO); |
81 | outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS); | |
82 | outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG); | |
9b748ed0 | 83 | spin_unlock(&scx_lock); |
1da177e4 LT |
84 | |
85 | scx200_wdt_ping(); | |
86 | } | |
87 | ||
88 | static void scx200_wdt_disable(void) | |
89 | { | |
27c766aa | 90 | pr_debug("disabling watchdog timer\n"); |
1da177e4 | 91 | |
9b748ed0 | 92 | spin_lock(&scx_lock); |
1da177e4 LT |
93 | outw(0, scx200_cb_base + SCx200_WDT_WDTO); |
94 | outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS); | |
95 | outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG); | |
9b748ed0 | 96 | spin_unlock(&scx_lock); |
1da177e4 LT |
97 | } |
98 | ||
99 | static int scx200_wdt_open(struct inode *inode, struct file *file) | |
100 | { | |
101 | /* only allow one at a time */ | |
9b748ed0 | 102 | if (test_and_set_bit(0, &open_lock)) |
1da177e4 LT |
103 | return -EBUSY; |
104 | scx200_wdt_enable(); | |
105 | ||
106 | return nonseekable_open(inode, file); | |
107 | } | |
108 | ||
109 | static int scx200_wdt_release(struct inode *inode, struct file *file) | |
110 | { | |
9b748ed0 | 111 | if (expect_close != 42) |
27c766aa | 112 | pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n"); |
9b748ed0 | 113 | else if (!nowayout) |
1da177e4 | 114 | scx200_wdt_disable(); |
1da177e4 | 115 | expect_close = 0; |
9b748ed0 | 116 | clear_bit(0, &open_lock); |
1da177e4 LT |
117 | |
118 | return 0; | |
119 | } | |
120 | ||
121 | static int scx200_wdt_notify_sys(struct notifier_block *this, | |
122 | unsigned long code, void *unused) | |
123 | { | |
124 | if (code == SYS_HALT || code == SYS_POWER_OFF) | |
125 | if (!nowayout) | |
126 | scx200_wdt_disable(); | |
127 | ||
128 | return NOTIFY_DONE; | |
129 | } | |
130 | ||
9b748ed0 | 131 | static struct notifier_block scx200_wdt_notifier = { |
1da177e4 LT |
132 | .notifier_call = scx200_wdt_notify_sys, |
133 | }; | |
134 | ||
135 | static ssize_t scx200_wdt_write(struct file *file, const char __user *data, | |
136 | size_t len, loff_t *ppos) | |
137 | { | |
138 | /* check for a magic close character */ | |
9b748ed0 | 139 | if (len) { |
1da177e4 LT |
140 | size_t i; |
141 | ||
142 | scx200_wdt_ping(); | |
143 | ||
144 | expect_close = 0; | |
145 | for (i = 0; i < len; ++i) { | |
146 | char c; | |
7944d3a5 | 147 | if (get_user(c, data + i)) |
1da177e4 LT |
148 | return -EFAULT; |
149 | if (c == 'V') | |
150 | expect_close = 42; | |
151 | } | |
152 | ||
153 | return len; | |
154 | } | |
155 | ||
156 | return 0; | |
157 | } | |
158 | ||
9b748ed0 AC |
159 | static long scx200_wdt_ioctl(struct file *file, unsigned int cmd, |
160 | unsigned long arg) | |
1da177e4 LT |
161 | { |
162 | void __user *argp = (void __user *)arg; | |
163 | int __user *p = argp; | |
9b748ed0 | 164 | static const struct watchdog_info ident = { |
1da177e4 LT |
165 | .identity = "NatSemi SCx200 Watchdog", |
166 | .firmware_version = 1, | |
e73a7802 WVS |
167 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
168 | WDIOF_MAGICCLOSE, | |
1da177e4 LT |
169 | }; |
170 | int new_margin; | |
171 | ||
172 | switch (cmd) { | |
1da177e4 | 173 | case WDIOC_GETSUPPORT: |
9b748ed0 | 174 | if (copy_to_user(argp, &ident, sizeof(ident))) |
1da177e4 LT |
175 | return -EFAULT; |
176 | return 0; | |
177 | case WDIOC_GETSTATUS: | |
178 | case WDIOC_GETBOOTSTATUS: | |
179 | if (put_user(0, p)) | |
180 | return -EFAULT; | |
181 | return 0; | |
182 | case WDIOC_KEEPALIVE: | |
183 | scx200_wdt_ping(); | |
184 | return 0; | |
185 | case WDIOC_SETTIMEOUT: | |
186 | if (get_user(new_margin, p)) | |
187 | return -EFAULT; | |
188 | if (new_margin < 1) | |
189 | return -EINVAL; | |
190 | margin = new_margin; | |
191 | scx200_wdt_update_margin(); | |
192 | scx200_wdt_ping(); | |
193 | case WDIOC_GETTIMEOUT: | |
194 | if (put_user(margin, p)) | |
195 | return -EFAULT; | |
196 | return 0; | |
0c06090c WVS |
197 | default: |
198 | return -ENOTTY; | |
1da177e4 LT |
199 | } |
200 | } | |
201 | ||
62322d25 | 202 | static const struct file_operations scx200_wdt_fops = { |
9b748ed0 AC |
203 | .owner = THIS_MODULE, |
204 | .llseek = no_llseek, | |
205 | .write = scx200_wdt_write, | |
206 | .unlocked_ioctl = scx200_wdt_ioctl, | |
207 | .open = scx200_wdt_open, | |
1da177e4 LT |
208 | .release = scx200_wdt_release, |
209 | }; | |
210 | ||
211 | static struct miscdevice scx200_wdt_miscdev = { | |
212 | .minor = WATCHDOG_MINOR, | |
9b748ed0 AC |
213 | .name = "watchdog", |
214 | .fops = &scx200_wdt_fops, | |
1da177e4 LT |
215 | }; |
216 | ||
217 | static int __init scx200_wdt_init(void) | |
218 | { | |
219 | int r; | |
220 | ||
27c766aa | 221 | pr_debug("NatSemi SCx200 Watchdog Driver\n"); |
1da177e4 LT |
222 | |
223 | /* check that we have found the configuration block */ | |
224 | if (!scx200_cb_present()) | |
225 | return -ENODEV; | |
226 | ||
227 | if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET, | |
228 | SCx200_WDT_SIZE, | |
229 | "NatSemi SCx200 Watchdog")) { | |
27c766aa | 230 | pr_warn("watchdog I/O region busy\n"); |
1da177e4 LT |
231 | return -EBUSY; |
232 | } | |
233 | ||
234 | scx200_wdt_update_margin(); | |
235 | scx200_wdt_disable(); | |
236 | ||
c6cb13ae | 237 | r = register_reboot_notifier(&scx200_wdt_notifier); |
1da177e4 | 238 | if (r) { |
27c766aa | 239 | pr_err("unable to register reboot notifier\n"); |
1da177e4 LT |
240 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
241 | SCx200_WDT_SIZE); | |
242 | return r; | |
243 | } | |
244 | ||
c6cb13ae | 245 | r = misc_register(&scx200_wdt_miscdev); |
1da177e4 | 246 | if (r) { |
c6cb13ae | 247 | unregister_reboot_notifier(&scx200_wdt_notifier); |
1da177e4 LT |
248 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
249 | SCx200_WDT_SIZE); | |
250 | return r; | |
251 | } | |
252 | ||
253 | return 0; | |
254 | } | |
255 | ||
256 | static void __exit scx200_wdt_cleanup(void) | |
257 | { | |
1da177e4 | 258 | misc_deregister(&scx200_wdt_miscdev); |
c6cb13ae | 259 | unregister_reboot_notifier(&scx200_wdt_notifier); |
1da177e4 LT |
260 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
261 | SCx200_WDT_SIZE); | |
262 | } | |
263 | ||
264 | module_init(scx200_wdt_init); | |
265 | module_exit(scx200_wdt_cleanup); | |
266 | ||
267 | /* | |
268 | Local variables: | |
9b748ed0 AC |
269 | compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules" |
270 | c-basic-offset: 8 | |
1da177e4 LT |
271 | End: |
272 | */ |