| /* |
| * IB700 Single Board Computer WDT driver for Linux 2.4.x |
| * |
| * (c) Copyright 2001 Charles Howes <chowes@vsol.net> |
| * |
| * Based on advantechwdt.c which is based on acquirewdt.c which |
| * is based on wdt.c. |
| * |
| * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl> |
| * |
| * Based on acquirewdt.c which is based on wdt.c. |
| * Original copyright messages: |
| * |
| * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. |
| * http://www.redhat.com |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide |
| * warranty for any of this software. This material is provided |
| * "AS-IS" and at no charge. |
| * |
| * (c) Copyright 1995 Alan Cox <alan@redhat.com> |
| * |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/module.h> |
| #include <linux/version.h> |
| #include <linux/types.h> |
| #include <linux/errno.h> |
| #include <linux/kernel.h> |
| #include <linux/sched.h> |
| #include <linux/miscdevice.h> |
| #include <linux/watchdog.h> |
| #include <linux/slab.h> |
| #include <linux/ioport.h> |
| #include <linux/fcntl.h> |
| #include <asm/io.h> |
| #include <asm/uaccess.h> |
| #include <asm/system.h> |
| #include <linux/notifier.h> |
| #include <linux/reboot.h> |
| #include <linux/init.h> |
| #include <linux/spinlock.h> |
| #include <linux/smp_lock.h> |
| |
| static int ibwdt_is_open; |
| static spinlock_t ibwdt_lock; |
| static int expect_close = 0; |
| |
| /* |
| * |
| * Watchdog Timer Configuration |
| * |
| * The function of the watchdog timer is to reset the system |
| * automatically and is defined at I/O port 0443H. To enable the |
| * watchdog timer and allow the system to reset, write I/O port 0443H. |
| * To disable the timer, write I/O port 0441H for the system to stop the |
| * watchdog function. The timer has a tolerance of 20% for its |
| * intervals. |
| * |
| * The following describes how the timer should be programmed. |
| * |
| * Enabling Watchdog: |
| * MOV AX,000FH (Choose the values from 0 to F) |
| * MOV DX,0443H |
| * OUT DX,AX |
| * |
| * Disabling Watchdog: |
| * MOV AX,000FH (Any value is fine.) |
| * MOV DX,0441H |
| * OUT DX,AX |
| * |
| * Watchdog timer control table: |
| * Level Value Time/sec | Level Value Time/sec |
| * 1 F 0 | 9 7 16 |
| * 2 E 2 | 10 6 18 |
| * 3 D 4 | 11 5 20 |
| * 4 C 6 | 12 4 22 |
| * 5 B 8 | 13 3 24 |
| * 6 A 10 | 14 2 26 |
| * 7 9 12 | 15 1 28 |
| * 8 8 14 | 16 0 30 |
| * |
| */ |
| |
| static int wd_times[] = { |
| 30, /* 0x0 */ |
| 28, /* 0x1 */ |
| 26, /* 0x2 */ |
| 24, /* 0x3 */ |
| 22, /* 0x4 */ |
| 20, /* 0x5 */ |
| 18, /* 0x6 */ |
| 16, /* 0x7 */ |
| 14, /* 0x8 */ |
| 12, /* 0x9 */ |
| 10, /* 0xA */ |
| 8, /* 0xB */ |
| 6, /* 0xC */ |
| 4, /* 0xD */ |
| 2, /* 0xE */ |
| 0, /* 0xF */ |
| }; |
| |
| #define WDT_STOP 0x441 |
| #define WDT_START 0x443 |
| |
| /* Default timeout */ |
| #define WD_TIMO 0 /* 30 seconds +/- 20%, from table */ |
| |
| static int wd_margin = WD_TIMO; |
| |
| #ifdef CONFIG_WATCHDOG_NOWAYOUT |
| static int nowayout = 1; |
| #else |
| static int nowayout = 0; |
| #endif |
| |
| MODULE_PARM(nowayout,"i"); |
| MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); |
| |
| |
| /* |
| * Kernel methods. |
| */ |
| |
| static void |
| ibwdt_ping(void) |
| { |
| /* Write a watchdog value */ |
| outb_p(wd_margin, WDT_START); |
| } |
| |
| static ssize_t |
| ibwdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos) |
| { |
| /* Can't seek (pwrite) on this device */ |
| if (ppos != &file->f_pos) |
| return -ESPIPE; |
| |
| if (count) { |
| if (!nowayout) { |
| size_t i; |
| |
| /* In case it was set long ago */ |
| expect_close = 0; |
| |
| for (i = 0; i != count; i++) { |
| char c; |
| if (get_user(c, buf + i)) |
| return -EFAULT; |
| if (c == 'V') |
| expect_close = 1; |
| } |
| } |
| ibwdt_ping(); |
| return 1; |
| } |
| return 0; |
| } |
| |
| static ssize_t |
| ibwdt_read(struct file *file, char *buf, size_t count, loff_t *ppos) |
| { |
| return -EINVAL; |
| } |
| |
| static int |
| ibwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, |
| unsigned long arg) |
| { |
| int i, new_margin; |
| |
| static struct watchdog_info ident = { |
| WDIOF_KEEPALIVEPING | |
| WDIOF_SETTIMEOUT | |
| WDIOF_MAGICCLOSE, |
| 1, "IB700 WDT" |
| }; |
| |
| switch (cmd) { |
| case WDIOC_GETSUPPORT: |
| if (copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident))) |
| return -EFAULT; |
| break; |
| |
| case WDIOC_GETSTATUS: |
| if (copy_to_user((int *)arg, &ibwdt_is_open, sizeof(int))) |
| return -EFAULT; |
| break; |
| |
| case WDIOC_KEEPALIVE: |
| ibwdt_ping(); |
| break; |
| |
| case WDIOC_SETTIMEOUT: |
| if (get_user(new_margin, (int *)arg)) |
| return -EFAULT; |
| if ((new_margin < 0) || (new_margin > 30)) |
| return -EINVAL; |
| for (i = 0x0F; i > -1; i--) |
| if (wd_times[i] > new_margin) |
| break; |
| wd_margin = i; |
| ibwdt_ping(); |
| /* Fall */ |
| |
| case WDIOC_GETTIMEOUT: |
| return put_user(wd_times[wd_margin], (int *)arg); |
| break; |
| |
| default: |
| return -ENOTTY; |
| } |
| return 0; |
| } |
| |
| static int |
| ibwdt_open(struct inode *inode, struct file *file) |
| { |
| switch (MINOR(inode->i_rdev)) { |
| case WATCHDOG_MINOR: |
| spin_lock(&ibwdt_lock); |
| if (ibwdt_is_open) { |
| spin_unlock(&ibwdt_lock); |
| return -EBUSY; |
| } |
| /* |
| * Activate |
| */ |
| |
| ibwdt_is_open = 1; |
| ibwdt_ping(); |
| spin_unlock(&ibwdt_lock); |
| return 0; |
| default: |
| return -ENODEV; |
| } |
| } |
| |
| static int |
| ibwdt_close(struct inode *inode, struct file *file) |
| { |
| lock_kernel(); |
| if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) { |
| spin_lock(&ibwdt_lock); |
| if (expect_close) { |
| outb_p(wd_times[wd_margin], WDT_STOP); |
| } else { |
| printk(KERN_CRIT "WDT device closed unexpectedly. WDT will not stop!\n"); |
| } |
| ibwdt_is_open = 0; |
| spin_unlock(&ibwdt_lock); |
| } |
| unlock_kernel(); |
| return 0; |
| } |
| |
| /* |
| * Notifier for system down |
| */ |
| |
| static int |
| ibwdt_notify_sys(struct notifier_block *this, unsigned long code, |
| void *unused) |
| { |
| if (code == SYS_DOWN || code == SYS_HALT) { |
| /* Turn the WDT off */ |
| outb_p(wd_times[wd_margin], WDT_STOP); |
| } |
| return NOTIFY_DONE; |
| } |
| |
| /* |
| * Kernel Interfaces |
| */ |
| |
| static struct file_operations ibwdt_fops = { |
| owner: THIS_MODULE, |
| read: ibwdt_read, |
| write: ibwdt_write, |
| ioctl: ibwdt_ioctl, |
| open: ibwdt_open, |
| release: ibwdt_close, |
| }; |
| |
| static struct miscdevice ibwdt_miscdev = { |
| WATCHDOG_MINOR, |
| "watchdog", |
| &ibwdt_fops |
| }; |
| |
| /* |
| * The WDT needs to learn about soft shutdowns in order to |
| * turn the timebomb registers off. |
| */ |
| |
| static struct notifier_block ibwdt_notifier = { |
| ibwdt_notify_sys, |
| NULL, |
| 0 |
| }; |
| |
| static int __init |
| ibwdt_init(void) |
| { |
| printk("WDT driver for IB700 single board computer initialising.\n"); |
| |
| spin_lock_init(&ibwdt_lock); |
| misc_register(&ibwdt_miscdev); |
| #if WDT_START != WDT_STOP |
| request_region(WDT_STOP, 1, "IB700 WDT"); |
| #endif |
| request_region(WDT_START, 1, "IB700 WDT"); |
| register_reboot_notifier(&ibwdt_notifier); |
| return 0; |
| } |
| |
| static void __exit |
| ibwdt_exit(void) |
| { |
| misc_deregister(&ibwdt_miscdev); |
| unregister_reboot_notifier(&ibwdt_notifier); |
| #if WDT_START != WDT_STOP |
| release_region(WDT_STOP,1); |
| #endif |
| release_region(WDT_START,1); |
| } |
| |
| module_init(ibwdt_init); |
| module_exit(ibwdt_exit); |
| |
| MODULE_AUTHOR("Charles Howes <chowes@vsol.net>"); |
| MODULE_DESCRIPTION("IB700 SBC watchdog driver"); |
| MODULE_LICENSE("GPL"); |
| |
| /* end of ib700wdt.c */ |