diff options
Diffstat (limited to 'drivers/char/watchdog/wdt285.c')
| -rw-r--r-- | drivers/char/watchdog/wdt285.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/drivers/char/watchdog/wdt285.c b/drivers/char/watchdog/wdt285.c new file mode 100644 index 00000000000..52825a1f177 --- /dev/null +++ b/drivers/char/watchdog/wdt285.c @@ -0,0 +1,229 @@ +/* + * Intel 21285 watchdog driver + * Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998 + * + * based on + * + * SoftDog 0.05: A Software Watchdog Device + * + * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. + * + * 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. + * + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/reboot.h> +#include <linux/init.h> +#include <linux/interrupt.h> + +#include <asm/irq.h> +#include <asm/uaccess.h> +#include <asm/hardware.h> +#include <asm/mach-types.h> +#include <asm/hardware/dec21285.h> + +/* + * Define this to stop the watchdog actually rebooting the machine. + */ +#undef ONLY_TESTING + +static unsigned int soft_margin = 60; /* in seconds */ +static unsigned int reload; +static unsigned long timer_alive; + +#ifdef ONLY_TESTING +/* + * If the timer expires.. + */ +static void watchdog_fire(int irq, void *dev_id, struct pt_regs *regs) +{ + printk(KERN_CRIT "Watchdog: Would Reboot.\n"); + *CSR_TIMER4_CNTL = 0; + *CSR_TIMER4_CLR = 0; +} +#endif + +/* + * Refresh the timer. + */ +static void watchdog_ping(void) +{ + *CSR_TIMER4_LOAD = reload; +} + +/* + * Allow only one person to hold it open + */ +static int watchdog_open(struct inode *inode, struct file *file) +{ + int ret; + + if (*CSR_SA110_CNTL & (1 << 13)) + return -EBUSY; + + if (test_and_set_bit(1, &timer_alive)) + return -EBUSY; + + reload = soft_margin * (mem_fclk_21285 / 256); + + *CSR_TIMER4_CLR = 0; + watchdog_ping(); + *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD + | TIMER_CNTL_DIV256; + +#ifdef ONLY_TESTING + ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL); + if (ret) { + *CSR_TIMER4_CNTL = 0; + clear_bit(1, &timer_alive); + } +#else + /* + * Setting this bit is irreversible; once enabled, there is + * no way to disable the watchdog. + */ + *CSR_SA110_CNTL |= 1 << 13; + + ret = 0; +#endif + nonseekable_open(inode, file); + return ret; +} + +/* + * Shut off the timer. + * Note: if we really have enabled the watchdog, there + * is no way to turn off. + */ +static int watchdog_release(struct inode *inode, struct file *file) +{ +#ifdef ONLY_TESTING + free_irq(IRQ_TIMER4, NULL); + clear_bit(1, &timer_alive); +#endif + return 0; +} + +static ssize_t +watchdog_write(struct file *file, const char *data, size_t len, loff_t *ppos) +{ + /* + * Refresh the timer. + */ + if (len) + watchdog_ping(); + + return len; +} + +static struct watchdog_info ident = { + .options = WDIOF_SETTIMEOUT, + .identity = "Footbridge Watchdog", +}; + +static int +watchdog_ioctl(struct inode *inode, struct file *file, unsigned int cmd, + unsigned long arg) +{ + unsigned int new_margin; + int ret = -ENOIOCTLCMD; + + switch(cmd) { + case WDIOC_GETSUPPORT: + ret = 0; + if (copy_to_user((void *)arg, &ident, sizeof(ident))) + ret = -EFAULT; + break; + + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + ret = put_user(0,(int *)arg); + break; + + case WDIOC_KEEPALIVE: + watchdog_ping(); + ret = 0; + break; + + case WDIOC_SETTIMEOUT: + ret = get_user(new_margin, (int *)arg); + if (ret) + break; + + /* Arbitrary, can't find the card's limits */ + if (new_margin < 0 || new_margin > 60) { + ret = -EINVAL; + break; + } + + soft_margin = new_margin; + reload = soft_margin * (mem_fclk_21285 / 256); + watchdog_ping(); + /* Fall */ + case WDIOC_GETTIMEOUT: + ret = put_user(soft_margin, (int *)arg); + break; + } + return ret; +} + +static struct file_operations watchdog_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = watchdog_write, + .ioctl = watchdog_ioctl, + .open = watchdog_open, + .release = watchdog_release, +}; + +static struct miscdevice watchdog_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &watchdog_fops, +}; + +static int __init footbridge_watchdog_init(void) +{ + int retval; + + if (machine_is_netwinder()) + return -ENODEV; + + retval = misc_register(&watchdog_miscdev); + if (retval < 0) + return retval; + + printk("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n", + soft_margin); + + if (machine_is_cats()) + printk("Warning: Watchdog reset may not work on this machine.\n"); + return 0; +} + +static void __exit footbridge_watchdog_exit(void) +{ + misc_deregister(&watchdog_miscdev); +} + +MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>"); +MODULE_DESCRIPTION("Footbridge watchdog driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); + +module_param(soft_margin, int, 0); +MODULE_PARM_DESC(soft_margin,"Watchdog timeout in seconds"); + +module_init(footbridge_watchdog_init); +module_exit(footbridge_watchdog_exit); |