diff options
Diffstat (limited to 'drivers/char/watchdog/acquirewdt.c')
| -rw-r--r-- | drivers/char/watchdog/acquirewdt.c | 332 |
1 files changed, 332 insertions, 0 deletions
diff --git a/drivers/char/watchdog/acquirewdt.c b/drivers/char/watchdog/acquirewdt.c new file mode 100644 index 00000000000..8f302121741 --- /dev/null +++ b/drivers/char/watchdog/acquirewdt.c @@ -0,0 +1,332 @@ +/* + * Acquire Single Board Computer Watchdog Timer driver + * + * 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> + * + * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> + * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT + * Can't add timeout - driver doesn't allow changing value + */ + +/* + * Theory of Operation: + * The Watch-Dog Timer is provided to ensure that standalone + * Systems can always recover from catastrophic conditions that + * caused the CPU to crash. This condition may have occured by + * external EMI or a software bug. When the CPU stops working + * correctly, hardware on the board will either perform a hardware + * reset (cold boot) or a non-maskable interrupt (NMI) to bring the + * system back to a known state. + * + * The Watch-Dog Timer is controlled by two I/O Ports. + * 443 hex - Read - Enable or refresh the Watch-Dog Timer + * 043 hex - Read - Disable the Watch-Dog Timer + * + * To enable the Watch-Dog Timer, a read from I/O port 443h must + * be performed. This will enable and activate the countdown timer + * which will eventually time out and either reset the CPU or cause + * an NMI depending on the setting of a jumper. To ensure that this + * reset condition does not occur, the Watch-Dog Timer must be + * periodically refreshed by reading the same I/O port 443h. + * The Watch-Dog Timer is disabled by reading I/O port 043h. + * + * The Watch-Dog Timer Time-Out Period is set via jumpers. + * It can be 1, 2, 10, 20, 110 or 220 seconds. + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/fs.h> +#include <linux/ioport.h> +#include <linux/notifier.h> +#include <linux/reboot.h> +#include <linux/init.h> + +#include <asm/io.h> +#include <asm/uaccess.h> +#include <asm/system.h> + +#define WATCHDOG_NAME "Acquire WDT" +#define PFX WATCHDOG_NAME ": " +#define WATCHDOG_HEARTBEAT 0 /* There is no way to see what the correct time-out period is */ + +static unsigned long acq_is_open; +static char expect_close; + +/* + * You must set these - there is no sane way to probe for this board. + */ + +static int wdt_stop = 0x43; +module_param(wdt_stop, int, 0); +MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)"); + +static int wdt_start = 0x443; +module_param(wdt_start, int, 0); +MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)"); + +#ifdef CONFIG_WATCHDOG_NOWAYOUT +static int nowayout = 1; +#else +static int nowayout = 0; +#endif + +module_param(nowayout, int, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); + +/* + * Kernel methods. + */ + +static void acq_keepalive(void) +{ + /* Write a watchdog value */ + inb_p(wdt_start); +} + +static void acq_stop(void) +{ + /* Turn the card off */ + inb_p(wdt_stop); +} + +/* + * /dev/watchdog handling. + */ + +static ssize_t acq_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) +{ + /* See if we got the magic character 'V' and reload the timer */ + if(count) { + if (!nowayout) { + size_t i; + + /* note: just in case someone wrote the magic character + * five months ago... */ + expect_close = 0; + + /* scan to see whether or not we got the magic character */ + for (i = 0; i != count; i++) { + char c; + if (get_user(c, buf + i)) + return -EFAULT; + if (c == 'V') + expect_close = 42; + } + } + + /* Well, anyhow someone wrote to us, we should return that favour */ + acq_keepalive(); + } + return count; +} + +static int acq_ioctl(struct inode *inode, struct file *file, unsigned int cmd, + unsigned long arg) +{ + int options, retval = -EINVAL; + void __user *argp = (void __user *)arg; + int __user *p = argp; + static struct watchdog_info ident = + { + .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, + .firmware_version = 1, + .identity = "Acquire WDT", + }; + + switch(cmd) + { + case WDIOC_GETSUPPORT: + return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; + + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, p); + + case WDIOC_KEEPALIVE: + acq_keepalive(); + return 0; + + case WDIOC_GETTIMEOUT: + return put_user(WATCHDOG_HEARTBEAT, p); + + case WDIOC_SETOPTIONS: + { + if (get_user(options, p)) + return -EFAULT; + + if (options & WDIOS_DISABLECARD) + { + acq_stop(); + retval = 0; + } + + if (options & WDIOS_ENABLECARD) + { + acq_keepalive(); + retval = 0; + } + + return retval; + } + + default: + return -ENOIOCTLCMD; + } +} + +static int acq_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(0, &acq_is_open)) + return -EBUSY; + + if (nowayout) + __module_get(THIS_MODULE); + + /* Activate */ + acq_keepalive(); + return nonseekable_open(inode, file); +} + +static int acq_close(struct inode *inode, struct file *file) +{ + if (expect_close == 42) { + acq_stop(); + } else { + printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); + acq_keepalive(); + } + clear_bit(0, &acq_is_open); + expect_close = 0; + return 0; +} + +/* + * Notifier for system down + */ + +static int acq_notify_sys(struct notifier_block *this, unsigned long code, + void *unused) +{ + if(code==SYS_DOWN || code==SYS_HALT) { + /* Turn the WDT off */ + acq_stop(); + } + return NOTIFY_DONE; +} + +/* + * Kernel Interfaces + */ + +static struct file_operations acq_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = acq_write, + .ioctl = acq_ioctl, + .open = acq_open, + .release = acq_close, +}; + +static struct miscdevice acq_miscdev= +{ + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &acq_fops, +}; + +/* + * The WDT card needs to learn about soft shutdowns in order to + * turn the timebomb registers off. + */ + +static struct notifier_block acq_notifier = +{ + .notifier_call = acq_notify_sys, +}; + +static int __init acq_init(void) +{ + int ret; + + printk(KERN_INFO "WDT driver for Acquire single board computer initialising.\n"); + + if (wdt_stop != wdt_start) { + if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) { + printk (KERN_ERR PFX "I/O address 0x%04x already in use\n", + wdt_stop); + ret = -EIO; + goto out; + } + } + + if (!request_region(wdt_start, 1, WATCHDOG_NAME)) { + printk (KERN_ERR PFX "I/O address 0x%04x already in use\n", + wdt_start); + ret = -EIO; + goto unreg_stop; + } + + ret = register_reboot_notifier(&acq_notifier); + if (ret != 0) { + printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", + ret); + goto unreg_regions; + } + + ret = misc_register(&acq_miscdev); + if (ret != 0) { + printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", + WATCHDOG_MINOR, ret); + goto unreg_reboot; + } + + printk (KERN_INFO PFX "initialized. (nowayout=%d)\n", + nowayout); + + return 0; + +unreg_reboot: + unregister_reboot_notifier(&acq_notifier); +unreg_regions: + release_region(wdt_start, 1); +unreg_stop: + if (wdt_stop != wdt_start) + release_region(wdt_stop, 1); +out: + return ret; +} + +static void __exit acq_exit(void) +{ + misc_deregister(&acq_miscdev); + unregister_reboot_notifier(&acq_notifier); + if(wdt_stop != wdt_start) + release_region(wdt_stop,1); + release_region(wdt_start,1); +} + +module_init(acq_init); +module_exit(acq_exit); + +MODULE_AUTHOR("David Woodhouse"); +MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |