diff options
Diffstat (limited to 'drivers/watchdog/sbc_epx_c3.c')
| -rw-r--r-- | drivers/watchdog/sbc_epx_c3.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/drivers/watchdog/sbc_epx_c3.c b/drivers/watchdog/sbc_epx_c3.c new file mode 100644 index 000000000..5e3a9ddb9 --- /dev/null +++ b/drivers/watchdog/sbc_epx_c3.c @@ -0,0 +1,219 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX-C3 + * single board computer + * + * (c) Copyright 2006 Calin A. Culianu <calin@ajvar.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/ioport.h> +#include <linux/uaccess.h> +#include <linux/io.h> + +static int epx_c3_alive; + +#define WATCHDOG_TIMEOUT 1 /* 1 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) ")"); + +#define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */ +#define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */ + +static void epx_c3_start(void) +{ + outb(1, EPXC3_WATCHDOG_CTL_REG); +} + +static void epx_c3_stop(void) +{ + + outb(0, EPXC3_WATCHDOG_CTL_REG); + + pr_info("Stopped watchdog timer\n"); +} + +static void epx_c3_pet(void) +{ + outb(1, EPXC3_WATCHDOG_PET_REG); +} + +/* + * Allow only one person to hold it open + */ +static int epx_c3_open(struct inode *inode, struct file *file) +{ + if (epx_c3_alive) + return -EBUSY; + + if (nowayout) + __module_get(THIS_MODULE); + + /* Activate timer */ + epx_c3_start(); + epx_c3_pet(); + + epx_c3_alive = 1; + pr_info("Started watchdog timer\n"); + + return stream_open(inode, file); +} + +static int epx_c3_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) + epx_c3_stop(); /* Turn the WDT off */ + + epx_c3_alive = 0; + + return 0; +} + +static ssize_t epx_c3_write(struct file *file, const char __user *data, + size_t len, loff_t *ppos) +{ + /* Refresh the timer. */ + if (len) + epx_c3_pet(); + return len; +} + +static long epx_c3_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + int options, retval = -EINVAL; + int __user *argp = (void __user *)arg; + static const struct watchdog_info ident = { + .options = WDIOF_KEEPALIVEPING, + .firmware_version = 0, + .identity = "Winsystems EPX-C3 H/W Watchdog", + }; + + switch (cmd) { + case WDIOC_GETSUPPORT: + if (copy_to_user(argp, &ident, sizeof(ident))) + return -EFAULT; + return 0; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, argp); + case WDIOC_SETOPTIONS: + if (get_user(options, argp)) + return -EFAULT; + + if (options & WDIOS_DISABLECARD) { + epx_c3_stop(); + retval = 0; + } + + if (options & WDIOS_ENABLECARD) { + epx_c3_start(); + retval = 0; + } + + return retval; + case WDIOC_KEEPALIVE: + epx_c3_pet(); + return 0; + case WDIOC_GETTIMEOUT: + return put_user(WATCHDOG_TIMEOUT, argp); + default: + return -ENOTTY; + } +} + +static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code, + void *unused) +{ + if (code == SYS_DOWN || code == SYS_HALT) + epx_c3_stop(); /* Turn the WDT off */ + + return NOTIFY_DONE; +} + +static const struct file_operations epx_c3_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = epx_c3_write, + .unlocked_ioctl = epx_c3_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .open = epx_c3_open, + .release = epx_c3_release, +}; + +static struct miscdevice epx_c3_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &epx_c3_fops, +}; + +static struct notifier_block epx_c3_notifier = { + .notifier_call = epx_c3_notify_sys, +}; + +static int __init watchdog_init(void) +{ + int ret; + + if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog")) + return -EBUSY; + + ret = register_reboot_notifier(&epx_c3_notifier); + if (ret) { + pr_err("cannot register reboot notifier (err=%d)\n", ret); + goto out; + } + + ret = misc_register(&epx_c3_miscdev); + if (ret) { + pr_err("cannot register miscdev on minor=%d (err=%d)\n", + WATCHDOG_MINOR, ret); + unregister_reboot_notifier(&epx_c3_notifier); + goto out; + } + + pr_info("Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n"); + + return 0; + +out: + release_region(EPXC3_WATCHDOG_CTL_REG, 2); + return ret; +} + +static void __exit watchdog_exit(void) +{ + misc_deregister(&epx_c3_miscdev); + unregister_reboot_notifier(&epx_c3_notifier); + release_region(EPXC3_WATCHDOG_CTL_REG, 2); +} + +module_init(watchdog_init); +module_exit(watchdog_exit); + +MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>"); +MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. " + "Note that there is no way to probe for this device -- " + "so only use it if you are *sure* you are running on this specific " + "SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!"); +MODULE_LICENSE("GPL"); |