diff options
Diffstat (limited to 'drivers/watchdog/indydog.c')
| -rw-r--r-- | drivers/watchdog/indydog.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/drivers/watchdog/indydog.c b/drivers/watchdog/indydog.c new file mode 100644 index 000000000..9857bb74a --- /dev/null +++ b/drivers/watchdog/indydog.c @@ -0,0 +1,204 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * IndyDog 0.3 A Hardware Watchdog Device for SGI IP22 + * + * (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>, + * All Rights Reserved. + * + * based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#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/notifier.h> +#include <linux/reboot.h> +#include <linux/init.h> +#include <linux/uaccess.h> +#include <asm/sgi/mc.h> + +static unsigned long indydog_alive; +static DEFINE_SPINLOCK(indydog_lock); + +#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, + "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +static void indydog_start(void) +{ + spin_lock(&indydog_lock); + sgimc->cpuctrl0 |= SGIMC_CCTRL0_WDOG; + spin_unlock(&indydog_lock); +} + +static void indydog_stop(void) +{ + spin_lock(&indydog_lock); + sgimc->cpuctrl0 &= ~SGIMC_CCTRL0_WDOG; + spin_unlock(&indydog_lock); + + pr_info("Stopped watchdog timer\n"); +} + +static void indydog_ping(void) +{ + sgimc->watchdogt = 0; +} + +/* + * Allow only one person to hold it open + */ +static int indydog_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(0, &indydog_alive)) + return -EBUSY; + + if (nowayout) + __module_get(THIS_MODULE); + + /* Activate timer */ + indydog_start(); + indydog_ping(); + + pr_info("Started watchdog timer\n"); + + return stream_open(inode, file); +} + +static int indydog_release(struct inode *inode, struct file *file) +{ + /* Shut off the timer. + * Lock it in if it's a module and we defined ...NOWAYOUT */ + if (!nowayout) + indydog_stop(); /* Turn the WDT off */ + clear_bit(0, &indydog_alive); + return 0; +} + +static ssize_t indydog_write(struct file *file, const char *data, + size_t len, loff_t *ppos) +{ + /* Refresh the timer. */ + if (len) + indydog_ping(); + return len; +} + +static long indydog_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + int options, retval = -EINVAL; + static const struct watchdog_info ident = { + .options = WDIOF_KEEPALIVEPING, + .firmware_version = 0, + .identity = "Hardware Watchdog for SGI IP22", + }; + + switch (cmd) { + case WDIOC_GETSUPPORT: + if (copy_to_user((struct watchdog_info *)arg, + &ident, sizeof(ident))) + return -EFAULT; + return 0; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, (int *)arg); + case WDIOC_SETOPTIONS: + { + if (get_user(options, (int *)arg)) + return -EFAULT; + if (options & WDIOS_DISABLECARD) { + indydog_stop(); + retval = 0; + } + if (options & WDIOS_ENABLECARD) { + indydog_start(); + retval = 0; + } + return retval; + } + case WDIOC_KEEPALIVE: + indydog_ping(); + return 0; + case WDIOC_GETTIMEOUT: + return put_user(WATCHDOG_TIMEOUT, (int *)arg); + default: + return -ENOTTY; + } +} + +static int indydog_notify_sys(struct notifier_block *this, + unsigned long code, void *unused) +{ + if (code == SYS_DOWN || code == SYS_HALT) + indydog_stop(); /* Turn the WDT off */ + + return NOTIFY_DONE; +} + +static const struct file_operations indydog_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = indydog_write, + .unlocked_ioctl = indydog_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .open = indydog_open, + .release = indydog_release, +}; + +static struct miscdevice indydog_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &indydog_fops, +}; + +static struct notifier_block indydog_notifier = { + .notifier_call = indydog_notify_sys, +}; + +static int __init watchdog_init(void) +{ + int ret; + + ret = register_reboot_notifier(&indydog_notifier); + if (ret) { + pr_err("cannot register reboot notifier (err=%d)\n", ret); + return ret; + } + + ret = misc_register(&indydog_miscdev); + if (ret) { + pr_err("cannot register miscdev on minor=%d (err=%d)\n", + WATCHDOG_MINOR, ret); + unregister_reboot_notifier(&indydog_notifier); + return ret; + } + + pr_info("Hardware Watchdog Timer for SGI IP22: 0.3\n"); + + return 0; +} + +static void __exit watchdog_exit(void) +{ + misc_deregister(&indydog_miscdev); + unregister_reboot_notifier(&indydog_notifier); +} + +module_init(watchdog_init); +module_exit(watchdog_exit); + +MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>"); +MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22"); +MODULE_LICENSE("GPL"); |