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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* 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
Joe Perches27c766a2012-02-15 15:06:19 -080020#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#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>
Jean Delvare6473d162007-03-06 02:45:12 -080030#include <linux/ioport.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#include <linux/scx200.h>
Alan Cox9b748ed2008-05-19 14:08:49 +010032#include <linux/uaccess.h>
33#include <linux/io.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Joe Perches27c766a2012-02-15 15:06:19 -080035#define DEBUG
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
37MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
38MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
39MODULE_LICENSE("GPL");
40MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
41
Linus Torvalds1da177e2005-04-16 15:20:36 -070042static int margin = 60; /* in seconds */
43module_param(margin, int, 0);
44MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
45
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010046static bool nowayout = WATCHDOG_NOWAYOUT;
47module_param(nowayout, bool, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070048MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
49
50static u16 wdto_restart;
Linus Torvalds1da177e2005-04-16 15:20:36 -070051static char expect_close;
Alan Cox9b748ed2008-05-19 14:08:49 +010052static unsigned long open_lock;
53static DEFINE_SPINLOCK(scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
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
62static void scx200_wdt_ping(void)
63{
Alan Cox9b748ed2008-05-19 14:08:49 +010064 spin_lock(&scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
Alan Cox9b748ed2008-05-19 14:08:49 +010066 spin_unlock(&scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067}
68
69static void scx200_wdt_update_margin(void)
70{
Joe Perches27c766a2012-02-15 15:06:19 -080071 pr_info("timer margin %d seconds\n", margin);
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 wdto_restart = margin * W_SCALE;
73}
74
75static void scx200_wdt_enable(void)
76{
Joe Perches27c766a2012-02-15 15:06:19 -080077 pr_debug("enabling watchdog timer, wdto_restart = %d\n", wdto_restart);
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
Alan Cox9b748ed2008-05-19 14:08:49 +010079 spin_lock(&scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080 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);
Alan Cox9b748ed2008-05-19 14:08:49 +010083 spin_unlock(&scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
85 scx200_wdt_ping();
86}
87
88static void scx200_wdt_disable(void)
89{
Joe Perches27c766a2012-02-15 15:06:19 -080090 pr_debug("disabling watchdog timer\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
Alan Cox9b748ed2008-05-19 14:08:49 +010092 spin_lock(&scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 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);
Alan Cox9b748ed2008-05-19 14:08:49 +010096 spin_unlock(&scx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070097}
98
99static int scx200_wdt_open(struct inode *inode, struct file *file)
100{
101 /* only allow one at a time */
Alan Cox9b748ed2008-05-19 14:08:49 +0100102 if (test_and_set_bit(0, &open_lock))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 return -EBUSY;
104 scx200_wdt_enable();
105
106 return nonseekable_open(inode, file);
107}
108
109static int scx200_wdt_release(struct inode *inode, struct file *file)
110{
Alan Cox9b748ed2008-05-19 14:08:49 +0100111 if (expect_close != 42)
Joe Perches27c766a2012-02-15 15:06:19 -0800112 pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
Alan Cox9b748ed2008-05-19 14:08:49 +0100113 else if (!nowayout)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 scx200_wdt_disable();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 expect_close = 0;
Alan Cox9b748ed2008-05-19 14:08:49 +0100116 clear_bit(0, &open_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117
118 return 0;
119}
120
121static 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
Alan Cox9b748ed2008-05-19 14:08:49 +0100131static struct notifier_block scx200_wdt_notifier = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 .notifier_call = scx200_wdt_notify_sys,
133};
134
135static 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 */
Alan Cox9b748ed2008-05-19 14:08:49 +0100139 if (len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 size_t i;
141
142 scx200_wdt_ping();
143
144 expect_close = 0;
145 for (i = 0; i < len; ++i) {
146 char c;
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000147 if (get_user(c, data + i))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 return -EFAULT;
149 if (c == 'V')
150 expect_close = 42;
151 }
152
153 return len;
154 }
155
156 return 0;
157}
158
Alan Cox9b748ed2008-05-19 14:08:49 +0100159static long scx200_wdt_ioctl(struct file *file, unsigned int cmd,
160 unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161{
162 void __user *argp = (void __user *)arg;
163 int __user *p = argp;
Alan Cox9b748ed2008-05-19 14:08:49 +0100164 static const struct watchdog_info ident = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 .identity = "NatSemi SCx200 Watchdog",
166 .firmware_version = 1,
Wim Van Sebroecke73a7802009-05-11 18:33:00 +0000167 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
168 WDIOF_MAGICCLOSE,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 };
170 int new_margin;
171
172 switch (cmd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 case WDIOC_GETSUPPORT:
Alan Cox9b748ed2008-05-19 14:08:49 +0100174 if (copy_to_user(argp, &ident, sizeof(ident)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 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;
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000197 default:
198 return -ENOTTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 }
200}
201
Arjan van de Ven62322d22006-07-03 00:24:21 -0700202static const struct file_operations scx200_wdt_fops = {
Alan Cox9b748ed2008-05-19 14:08:49 +0100203 .owner = THIS_MODULE,
204 .llseek = no_llseek,
205 .write = scx200_wdt_write,
206 .unlocked_ioctl = scx200_wdt_ioctl,
207 .open = scx200_wdt_open,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 .release = scx200_wdt_release,
209};
210
211static struct miscdevice scx200_wdt_miscdev = {
212 .minor = WATCHDOG_MINOR,
Alan Cox9b748ed2008-05-19 14:08:49 +0100213 .name = "watchdog",
214 .fops = &scx200_wdt_fops,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215};
216
217static int __init scx200_wdt_init(void)
218{
219 int r;
220
Joe Perches27c766a2012-02-15 15:06:19 -0800221 pr_debug("NatSemi SCx200 Watchdog Driver\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222
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")) {
Joe Perches27c766a2012-02-15 15:06:19 -0800230 pr_warn("watchdog I/O region busy\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 return -EBUSY;
232 }
233
234 scx200_wdt_update_margin();
235 scx200_wdt_disable();
236
Wim Van Sebroeckc6cb13a2007-12-26 20:32:51 +0000237 r = register_reboot_notifier(&scx200_wdt_notifier);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 if (r) {
Joe Perches27c766a2012-02-15 15:06:19 -0800239 pr_err("unable to register reboot notifier\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
241 SCx200_WDT_SIZE);
242 return r;
243 }
244
Wim Van Sebroeckc6cb13a2007-12-26 20:32:51 +0000245 r = misc_register(&scx200_wdt_miscdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 if (r) {
Wim Van Sebroeckc6cb13a2007-12-26 20:32:51 +0000247 unregister_reboot_notifier(&scx200_wdt_notifier);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
249 SCx200_WDT_SIZE);
250 return r;
251 }
252
253 return 0;
254}
255
256static void __exit scx200_wdt_cleanup(void)
257{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 misc_deregister(&scx200_wdt_miscdev);
Wim Van Sebroeckc6cb13a2007-12-26 20:32:51 +0000259 unregister_reboot_notifier(&scx200_wdt_notifier);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 release_region(scx200_cb_base + SCx200_WDT_OFFSET,
261 SCx200_WDT_SIZE);
262}
263
264module_init(scx200_wdt_init);
265module_exit(scx200_wdt_cleanup);
266
267/*
268 Local variables:
Alan Cox9b748ed2008-05-19 14:08:49 +0100269 compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
270 c-basic-offset: 8
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 End:
272*/