Commit | Line | Data |
---|---|---|
2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* drivers/char/watchdog/scx200_wdt.c |
3 | ||
4 | National Semiconductor SCx200 Watchdog support | |
5 | ||
6 | Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> | |
7 | ||
8 | Some code taken from: | |
9 | National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver | |
10 | (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com> | |
11 | ||
1da177e4 LT |
12 | |
13 | The author(s) of this software shall not be held liable for damages | |
14 | of any nature resulting due to the use of this software. This | |
15 | software is provided AS-IS with no warranties. */ | |
16 | ||
27c766aa JP |
17 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
18 | ||
1da177e4 LT |
19 | #include <linux/module.h> |
20 | #include <linux/moduleparam.h> | |
21 | #include <linux/init.h> | |
22 | #include <linux/miscdevice.h> | |
23 | #include <linux/watchdog.h> | |
24 | #include <linux/notifier.h> | |
25 | #include <linux/reboot.h> | |
26 | #include <linux/fs.h> | |
6473d160 | 27 | #include <linux/ioport.h> |
1da177e4 | 28 | #include <linux/scx200.h> |
9b748ed0 AC |
29 | #include <linux/uaccess.h> |
30 | #include <linux/io.h> | |
1da177e4 | 31 | |
27c766aa | 32 | #define DEBUG |
1da177e4 LT |
33 | |
34 | MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); | |
35 | MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver"); | |
36 | MODULE_LICENSE("GPL"); | |
1da177e4 | 37 | |
1da177e4 LT |
38 | static int margin = 60; /* in seconds */ |
39 | module_param(margin, int, 0); | |
40 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds"); | |
41 | ||
86a1e189 WVS |
42 | static bool nowayout = WATCHDOG_NOWAYOUT; |
43 | module_param(nowayout, bool, 0); | |
1da177e4 LT |
44 | MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); |
45 | ||
46 | static u16 wdto_restart; | |
1da177e4 | 47 | static char expect_close; |
9b748ed0 AC |
48 | static unsigned long open_lock; |
49 | static DEFINE_SPINLOCK(scx_lock); | |
1da177e4 LT |
50 | |
51 | /* Bits of the WDCNFG register */ | |
52 | #define W_ENABLE 0x00fa /* Enable watchdog */ | |
53 | #define W_DISABLE 0x0000 /* Disable watchdog */ | |
54 | ||
55 | /* The scaling factor for the timer, this depends on the value of W_ENABLE */ | |
56 | #define W_SCALE (32768/1024) | |
57 | ||
58 | static void scx200_wdt_ping(void) | |
59 | { | |
9b748ed0 | 60 | spin_lock(&scx_lock); |
1da177e4 | 61 | outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO); |
9b748ed0 | 62 | spin_unlock(&scx_lock); |
1da177e4 LT |
63 | } |
64 | ||
65 | static void scx200_wdt_update_margin(void) | |
66 | { | |
27c766aa | 67 | pr_info("timer margin %d seconds\n", margin); |
1da177e4 LT |
68 | wdto_restart = margin * W_SCALE; |
69 | } | |
70 | ||
71 | static void scx200_wdt_enable(void) | |
72 | { | |
27c766aa | 73 | pr_debug("enabling watchdog timer, wdto_restart = %d\n", wdto_restart); |
1da177e4 | 74 | |
9b748ed0 | 75 | spin_lock(&scx_lock); |
1da177e4 LT |
76 | outw(0, scx200_cb_base + SCx200_WDT_WDTO); |
77 | outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS); | |
78 | outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG); | |
9b748ed0 | 79 | spin_unlock(&scx_lock); |
1da177e4 LT |
80 | |
81 | scx200_wdt_ping(); | |
82 | } | |
83 | ||
84 | static void scx200_wdt_disable(void) | |
85 | { | |
27c766aa | 86 | pr_debug("disabling watchdog timer\n"); |
1da177e4 | 87 | |
9b748ed0 | 88 | spin_lock(&scx_lock); |
1da177e4 LT |
89 | outw(0, scx200_cb_base + SCx200_WDT_WDTO); |
90 | outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS); | |
91 | outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG); | |
9b748ed0 | 92 | spin_unlock(&scx_lock); |
1da177e4 LT |
93 | } |
94 | ||
95 | static int scx200_wdt_open(struct inode *inode, struct file *file) | |
96 | { | |
97 | /* only allow one at a time */ | |
9b748ed0 | 98 | if (test_and_set_bit(0, &open_lock)) |
1da177e4 LT |
99 | return -EBUSY; |
100 | scx200_wdt_enable(); | |
101 | ||
c5bf68fe | 102 | return stream_open(inode, file); |
1da177e4 LT |
103 | } |
104 | ||
105 | static int scx200_wdt_release(struct inode *inode, struct file *file) | |
106 | { | |
9b748ed0 | 107 | if (expect_close != 42) |
27c766aa | 108 | pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n"); |
9b748ed0 | 109 | else if (!nowayout) |
1da177e4 | 110 | scx200_wdt_disable(); |
1da177e4 | 111 | expect_close = 0; |
9b748ed0 | 112 | clear_bit(0, &open_lock); |
1da177e4 LT |
113 | |
114 | return 0; | |
115 | } | |
116 | ||
117 | static int scx200_wdt_notify_sys(struct notifier_block *this, | |
118 | unsigned long code, void *unused) | |
119 | { | |
120 | if (code == SYS_HALT || code == SYS_POWER_OFF) | |
121 | if (!nowayout) | |
122 | scx200_wdt_disable(); | |
123 | ||
124 | return NOTIFY_DONE; | |
125 | } | |
126 | ||
9b748ed0 | 127 | static struct notifier_block scx200_wdt_notifier = { |
1da177e4 LT |
128 | .notifier_call = scx200_wdt_notify_sys, |
129 | }; | |
130 | ||
131 | static ssize_t scx200_wdt_write(struct file *file, const char __user *data, | |
132 | size_t len, loff_t *ppos) | |
133 | { | |
134 | /* check for a magic close character */ | |
9b748ed0 | 135 | if (len) { |
1da177e4 LT |
136 | size_t i; |
137 | ||
138 | scx200_wdt_ping(); | |
139 | ||
140 | expect_close = 0; | |
141 | for (i = 0; i < len; ++i) { | |
142 | char c; | |
7944d3a5 | 143 | if (get_user(c, data + i)) |
1da177e4 LT |
144 | return -EFAULT; |
145 | if (c == 'V') | |
146 | expect_close = 42; | |
147 | } | |
148 | ||
149 | return len; | |
150 | } | |
151 | ||
152 | return 0; | |
153 | } | |
154 | ||
9b748ed0 AC |
155 | static long scx200_wdt_ioctl(struct file *file, unsigned int cmd, |
156 | unsigned long arg) | |
1da177e4 LT |
157 | { |
158 | void __user *argp = (void __user *)arg; | |
159 | int __user *p = argp; | |
9b748ed0 | 160 | static const struct watchdog_info ident = { |
1da177e4 LT |
161 | .identity = "NatSemi SCx200 Watchdog", |
162 | .firmware_version = 1, | |
e73a7802 WVS |
163 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
164 | WDIOF_MAGICCLOSE, | |
1da177e4 LT |
165 | }; |
166 | int new_margin; | |
167 | ||
168 | switch (cmd) { | |
1da177e4 | 169 | case WDIOC_GETSUPPORT: |
9b748ed0 | 170 | if (copy_to_user(argp, &ident, sizeof(ident))) |
1da177e4 LT |
171 | return -EFAULT; |
172 | return 0; | |
173 | case WDIOC_GETSTATUS: | |
174 | case WDIOC_GETBOOTSTATUS: | |
175 | if (put_user(0, p)) | |
176 | return -EFAULT; | |
177 | return 0; | |
178 | case WDIOC_KEEPALIVE: | |
179 | scx200_wdt_ping(); | |
180 | return 0; | |
181 | case WDIOC_SETTIMEOUT: | |
182 | if (get_user(new_margin, p)) | |
183 | return -EFAULT; | |
184 | if (new_margin < 1) | |
185 | return -EINVAL; | |
186 | margin = new_margin; | |
187 | scx200_wdt_update_margin(); | |
188 | scx200_wdt_ping(); | |
55a1b87e | 189 | fallthrough; |
1da177e4 LT |
190 | case WDIOC_GETTIMEOUT: |
191 | if (put_user(margin, p)) | |
192 | return -EFAULT; | |
193 | return 0; | |
0c06090c WVS |
194 | default: |
195 | return -ENOTTY; | |
1da177e4 LT |
196 | } |
197 | } | |
198 | ||
62322d25 | 199 | static const struct file_operations scx200_wdt_fops = { |
9b748ed0 AC |
200 | .owner = THIS_MODULE, |
201 | .llseek = no_llseek, | |
202 | .write = scx200_wdt_write, | |
203 | .unlocked_ioctl = scx200_wdt_ioctl, | |
b6dfb247 | 204 | .compat_ioctl = compat_ptr_ioctl, |
9b748ed0 | 205 | .open = scx200_wdt_open, |
1da177e4 LT |
206 | .release = scx200_wdt_release, |
207 | }; | |
208 | ||
209 | static struct miscdevice scx200_wdt_miscdev = { | |
210 | .minor = WATCHDOG_MINOR, | |
9b748ed0 AC |
211 | .name = "watchdog", |
212 | .fops = &scx200_wdt_fops, | |
1da177e4 LT |
213 | }; |
214 | ||
215 | static int __init scx200_wdt_init(void) | |
216 | { | |
217 | int r; | |
218 | ||
27c766aa | 219 | pr_debug("NatSemi SCx200 Watchdog Driver\n"); |
1da177e4 LT |
220 | |
221 | /* check that we have found the configuration block */ | |
222 | if (!scx200_cb_present()) | |
223 | return -ENODEV; | |
224 | ||
225 | if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET, | |
226 | SCx200_WDT_SIZE, | |
227 | "NatSemi SCx200 Watchdog")) { | |
27c766aa | 228 | pr_warn("watchdog I/O region busy\n"); |
1da177e4 LT |
229 | return -EBUSY; |
230 | } | |
231 | ||
232 | scx200_wdt_update_margin(); | |
233 | scx200_wdt_disable(); | |
234 | ||
c6cb13ae | 235 | r = register_reboot_notifier(&scx200_wdt_notifier); |
1da177e4 | 236 | if (r) { |
27c766aa | 237 | pr_err("unable to register reboot notifier\n"); |
1da177e4 LT |
238 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
239 | SCx200_WDT_SIZE); | |
240 | return r; | |
241 | } | |
242 | ||
c6cb13ae | 243 | r = misc_register(&scx200_wdt_miscdev); |
1da177e4 | 244 | if (r) { |
c6cb13ae | 245 | unregister_reboot_notifier(&scx200_wdt_notifier); |
1da177e4 LT |
246 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
247 | SCx200_WDT_SIZE); | |
248 | return r; | |
249 | } | |
250 | ||
251 | return 0; | |
252 | } | |
253 | ||
254 | static void __exit scx200_wdt_cleanup(void) | |
255 | { | |
1da177e4 | 256 | misc_deregister(&scx200_wdt_miscdev); |
c6cb13ae | 257 | unregister_reboot_notifier(&scx200_wdt_notifier); |
1da177e4 LT |
258 | release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
259 | SCx200_WDT_SIZE); | |
260 | } | |
261 | ||
262 | module_init(scx200_wdt_init); | |
263 | module_exit(scx200_wdt_cleanup); |