diff options
Diffstat (limited to 'drivers/char/wdt285.c')
| -rw-r--r-- | drivers/char/wdt285.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/drivers/char/wdt285.c b/drivers/char/wdt285.c new file mode 100644 index 000000000..b5dc94e2f --- /dev/null +++ b/drivers/char/wdt285.c @@ -0,0 +1,204 @@ +/* + * 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@cymru.net>, All Rights Reserved. + * http://www.cymru.net + * + * 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/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/system.h> +#include <asm/dec21285.h> + +/* + * Define this to stop the watchdog actually rebooting the machine. + */ +#undef ONLY_TESTING + +#define TIMER_MARGIN 60 /* (secs) Default is 1 minute */ + +#define FCLK (50*1000*1000) /* 50MHz */ + +static int soft_margin = TIMER_MARGIN; /* in seconds */ +static int timer_alive = 0; + +#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 + +static void watchdog_ping(void) +{ + /* + * Refresh the timer. + */ + *CSR_TIMER4_LOAD = soft_margin * (FCLK / 256); +} + +/* + * Allow only one person to hold it open + */ + +static int watchdog_open(struct inode *inode, struct file *file) +{ + if(timer_alive) + return -EBUSY; + MOD_INC_USE_COUNT; + /* + * Ahead watchdog factor ten, Mr Sulu + */ + *CSR_TIMER4_CLR = 0; + watchdog_ping(); + *CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD + | TIMER_CNTL_DIV256; +#ifdef ONLY_TESTING + request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL); +#else + *CSR_SA110_CNTL |= 1 << 13; +#endif + timer_alive = 1; + return 0; +} + +static int watchdog_release(struct inode *inode, struct file *file) +{ +#ifdef ONLY_TESTING + free_irq(IRQ_TIMER4, NULL); + timer_alive = 0; + MOD_DEC_USE_COUNT; +#else + /* + * It's irreversible! + */ +#endif + return 0; +} + +static ssize_t watchdog_write(struct file *file, const char *data, size_t len, loff_t *ppos) +{ + /* Can't seek (pwrite) on this device */ + if (ppos != &file->f_pos) + return -ESPIPE; + + /* + * Refresh the timer. + */ + if(len) + { + watchdog_ping(); + return 1; + } + return 0; +} + +static int watchdog_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg) +{ + int i; + static struct watchdog_info ident= + { + 0, + 0, + "Footbridge Watchdog" + }; + switch(cmd) + { + default: + return -ENOIOCTLCMD; + case WDIOC_GETSUPPORT: + i = verify_area(VERIFY_WRITE, (void*) arg, sizeof(struct watchdog_info)); + if (i) + return i; + else + return copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)); + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0,(int *)arg); + case WDIOC_KEEPALIVE: + watchdog_ping(); + return 0; + } +} + +static struct file_operations watchdog_fops= +{ + NULL, /* Seek */ + NULL, /* Read */ + watchdog_write, /* Write */ + NULL, /* Readdir */ + NULL, /* Select */ + watchdog_ioctl, /* Ioctl */ + NULL, /* MMap */ + watchdog_open, + NULL, /* flush */ + watchdog_release, + NULL, + NULL /* Fasync */ +}; + +static struct miscdevice watchdog_miscdev= +{ + WATCHDOG_MINOR, + "watchdog", + &watchdog_fops +}; + +static int __init footbridge_watchdog_init(void) +{ + if (machine_is_netwinder()) + return -ENODEV; + + misc_register(&watchdog_miscdev); + 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); +} + +EXPORT_NO_SYMBOLS; + +MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>"); +MODULE_DESCRIPTION("21285 watchdog driver"); + +MODULE_PARM(soft_margin,"i"); +MODULE_PARM_DESC(soft_margin,"Watchdog timeout in seconds"); + +module_init(footbridge_watchdog_init); +module_exit(footbridge_watchdog_exit); |