1 /* drivers/char/watchdog/scx200_wdt.c
3 National Semiconductor SCx200 Watchdog support
5 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
8 National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
9 (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>
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.
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. */
20 #include <linux/config.h>
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/init.h>
24 #include <linux/miscdevice.h>
25 #include <linux/watchdog.h>
26 #include <linux/notifier.h>
27 #include <linux/reboot.h>
29 #include <linux/pci.h>
30 #include <linux/scx200.h>
32 #include <asm/uaccess.h>
35 #define NAME "scx200_wdt"
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);
42 #ifndef CONFIG_WATCHDOG_NOWAYOUT
43 #define CONFIG_WATCHDOG_NOWAYOUT 0
46 static int margin = 60; /* in seconds */
47 module_param(margin, int, 0);
48 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
50 static int nowayout = CONFIG_WATCHDOG_NOWAYOUT;
51 module_param(nowayout, int, 0);
52 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
54 static u16 wdto_restart;
55 static struct semaphore open_semaphore;
56 static char expect_close;
58 /* Bits of the WDCNFG register */
59 #define W_ENABLE 0x00fa /* Enable watchdog */
60 #define W_DISABLE 0x0000 /* Disable watchdog */
62 /* The scaling factor for the timer, this depends on the value of W_ENABLE */
63 #define W_SCALE (32768/1024)
65 static void scx200_wdt_ping(void)
67 outw(wdto_restart, SCx200_CB_BASE + SCx200_WDT_WDTO);
70 static void scx200_wdt_update_margin(void)
72 printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
73 wdto_restart = margin * W_SCALE;
76 static void scx200_wdt_enable(void)
78 printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n",
81 outw(0, SCx200_CB_BASE + SCx200_WDT_WDTO);
82 outb(SCx200_WDT_WDSTS_WDOVF, SCx200_CB_BASE + SCx200_WDT_WDSTS);
83 outw(W_ENABLE, SCx200_CB_BASE + SCx200_WDT_WDCNFG);
88 static void scx200_wdt_disable(void)
90 printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
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);
97 static int scx200_wdt_open(struct inode *inode, struct file *file)
99 /* only allow one at a time */
100 if (down_trylock(&open_semaphore))
107 static int scx200_wdt_release(struct inode *inode, struct file *file)
109 if (expect_close != 42) {
110 printk(KERN_WARNING NAME ": watchdog device closed unexpectedly, will not disable the watchdog timer\n");
111 } else if (!nowayout) {
112 scx200_wdt_disable();
120 static int scx200_wdt_notify_sys(struct notifier_block *this,
121 unsigned long code, void *unused)
123 if (code == SYS_HALT || code == SYS_POWER_OFF)
125 scx200_wdt_disable();
130 static struct notifier_block scx200_wdt_notifier =
132 .notifier_call = scx200_wdt_notify_sys,
135 static ssize_t scx200_wdt_write(struct file *file, const char __user *data,
136 size_t len, loff_t *ppos)
138 if (ppos != &file->f_pos)
141 /* check for a magic close character */
149 for (i = 0; i < len; ++i) {
151 if (get_user(c, data+i))
163 static int scx200_wdt_ioctl(struct inode *inode, struct file *file,
164 unsigned int cmd, unsigned long arg)
166 void __user *argp = (void __user *)arg;
167 int __user *p = argp;
168 static struct watchdog_info ident = {
169 .identity = "NatSemi SCx200 Watchdog",
170 .firmware_version = 1,
171 .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING),
178 case WDIOC_GETSUPPORT:
179 if(copy_to_user(argp, &ident, sizeof(ident)))
182 case WDIOC_GETSTATUS:
183 case WDIOC_GETBOOTSTATUS:
187 case WDIOC_KEEPALIVE:
190 case WDIOC_SETTIMEOUT:
191 if (get_user(new_margin, p))
196 scx200_wdt_update_margin();
198 case WDIOC_GETTIMEOUT:
199 if (put_user(margin, p))
205 static struct file_operations scx200_wdt_fops = {
206 .owner = THIS_MODULE,
207 .write = scx200_wdt_write,
208 .ioctl = scx200_wdt_ioctl,
209 .open = scx200_wdt_open,
210 .release = scx200_wdt_release,
213 static struct miscdevice scx200_wdt_miscdev = {
214 .minor = WATCHDOG_MINOR,
216 .fops = &scx200_wdt_fops,
219 static int __init scx200_wdt_init(void)
223 printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n");
226 * First check that this really is a NatSemi SCx200 CPU or a Geode
229 if ((pci_find_device(PCI_VENDOR_ID_NS,
230 PCI_DEVICE_ID_NS_SCx200_BRIDGE,
232 && (pci_find_device(PCI_VENDOR_ID_NS,
233 PCI_DEVICE_ID_NS_SC1100_BRIDGE,
237 /* More sanity checks, verify that the configuration block is there */
238 if (!scx200_cb_probe(SCx200_CB_BASE)) {
239 printk(KERN_WARNING NAME ": no configuration block found\n");
243 if (!request_region(SCx200_CB_BASE + SCx200_WDT_OFFSET,
245 "NatSemi SCx200 Watchdog")) {
246 printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
250 scx200_wdt_update_margin();
251 scx200_wdt_disable();
253 sema_init(&open_semaphore, 1);
255 r = misc_register(&scx200_wdt_miscdev);
257 release_region(SCx200_CB_BASE + SCx200_WDT_OFFSET,
262 r = register_reboot_notifier(&scx200_wdt_notifier);
264 printk(KERN_ERR NAME ": unable to register reboot notifier");
265 misc_deregister(&scx200_wdt_miscdev);
266 release_region(SCx200_CB_BASE + SCx200_WDT_OFFSET,
274 static void __exit scx200_wdt_cleanup(void)
276 unregister_reboot_notifier(&scx200_wdt_notifier);
277 misc_deregister(&scx200_wdt_miscdev);
278 release_region(SCx200_CB_BASE + SCx200_WDT_OFFSET,
282 module_init(scx200_wdt_init);
283 module_exit(scx200_wdt_cleanup);
287 compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"