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219 lines
4.8 KiB
219 lines
4.8 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX-C3 |
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* single board computer |
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* |
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* (c) Copyright 2006 Calin A. Culianu <[email protected]>, All Rights |
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* Reserved. |
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* |
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* based on softdog.c by Alan Cox <[email protected]> |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/fs.h> |
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#include <linux/mm.h> |
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#include <linux/miscdevice.h> |
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#include <linux/watchdog.h> |
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#include <linux/notifier.h> |
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#include <linux/reboot.h> |
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#include <linux/init.h> |
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#include <linux/ioport.h> |
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#include <linux/uaccess.h> |
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#include <linux/io.h> |
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static int epx_c3_alive; |
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#define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */ |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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module_param(nowayout, bool, 0); |
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
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#define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */ |
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#define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */ |
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static void epx_c3_start(void) |
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{ |
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outb(1, EPXC3_WATCHDOG_CTL_REG); |
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} |
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static void epx_c3_stop(void) |
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{ |
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outb(0, EPXC3_WATCHDOG_CTL_REG); |
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pr_info("Stopped watchdog timer\n"); |
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} |
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static void epx_c3_pet(void) |
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{ |
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outb(1, EPXC3_WATCHDOG_PET_REG); |
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} |
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/* |
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* Allow only one person to hold it open |
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*/ |
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static int epx_c3_open(struct inode *inode, struct file *file) |
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{ |
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if (epx_c3_alive) |
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return -EBUSY; |
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if (nowayout) |
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__module_get(THIS_MODULE); |
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/* Activate timer */ |
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epx_c3_start(); |
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epx_c3_pet(); |
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epx_c3_alive = 1; |
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pr_info("Started watchdog timer\n"); |
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return stream_open(inode, file); |
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} |
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static int epx_c3_release(struct inode *inode, struct file *file) |
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{ |
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/* Shut off the timer. |
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* Lock it in if it's a module and we defined ...NOWAYOUT */ |
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if (!nowayout) |
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epx_c3_stop(); /* Turn the WDT off */ |
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epx_c3_alive = 0; |
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return 0; |
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} |
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static ssize_t epx_c3_write(struct file *file, const char __user *data, |
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size_t len, loff_t *ppos) |
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{ |
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/* Refresh the timer. */ |
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if (len) |
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epx_c3_pet(); |
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return len; |
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} |
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static long epx_c3_ioctl(struct file *file, unsigned int cmd, |
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unsigned long arg) |
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{ |
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int options, retval = -EINVAL; |
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int __user *argp = (void __user *)arg; |
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static const struct watchdog_info ident = { |
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.options = WDIOF_KEEPALIVEPING, |
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.firmware_version = 0, |
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.identity = "Winsystems EPX-C3 H/W Watchdog", |
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}; |
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switch (cmd) { |
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case WDIOC_GETSUPPORT: |
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if (copy_to_user(argp, &ident, sizeof(ident))) |
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return -EFAULT; |
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return 0; |
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case WDIOC_GETSTATUS: |
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case WDIOC_GETBOOTSTATUS: |
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return put_user(0, argp); |
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case WDIOC_SETOPTIONS: |
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if (get_user(options, argp)) |
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return -EFAULT; |
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if (options & WDIOS_DISABLECARD) { |
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epx_c3_stop(); |
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retval = 0; |
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} |
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if (options & WDIOS_ENABLECARD) { |
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epx_c3_start(); |
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retval = 0; |
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} |
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return retval; |
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case WDIOC_KEEPALIVE: |
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epx_c3_pet(); |
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return 0; |
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case WDIOC_GETTIMEOUT: |
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return put_user(WATCHDOG_TIMEOUT, argp); |
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default: |
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return -ENOTTY; |
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} |
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} |
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static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code, |
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void *unused) |
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{ |
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if (code == SYS_DOWN || code == SYS_HALT) |
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epx_c3_stop(); /* Turn the WDT off */ |
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return NOTIFY_DONE; |
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} |
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static const struct file_operations epx_c3_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.write = epx_c3_write, |
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.unlocked_ioctl = epx_c3_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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.open = epx_c3_open, |
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.release = epx_c3_release, |
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}; |
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static struct miscdevice epx_c3_miscdev = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &epx_c3_fops, |
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}; |
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static struct notifier_block epx_c3_notifier = { |
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.notifier_call = epx_c3_notify_sys, |
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}; |
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static int __init watchdog_init(void) |
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{ |
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int ret; |
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if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog")) |
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return -EBUSY; |
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ret = register_reboot_notifier(&epx_c3_notifier); |
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if (ret) { |
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pr_err("cannot register reboot notifier (err=%d)\n", ret); |
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goto out; |
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} |
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ret = misc_register(&epx_c3_miscdev); |
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if (ret) { |
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pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
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WATCHDOG_MINOR, ret); |
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unregister_reboot_notifier(&epx_c3_notifier); |
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goto out; |
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} |
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pr_info("Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n"); |
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return 0; |
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out: |
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release_region(EPXC3_WATCHDOG_CTL_REG, 2); |
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return ret; |
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} |
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static void __exit watchdog_exit(void) |
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{ |
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misc_deregister(&epx_c3_miscdev); |
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unregister_reboot_notifier(&epx_c3_notifier); |
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release_region(EPXC3_WATCHDOG_CTL_REG, 2); |
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} |
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module_init(watchdog_init); |
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module_exit(watchdog_exit); |
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MODULE_AUTHOR("Calin A. Culianu <[email protected]>"); |
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MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. " |
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"Note that there is no way to probe for this device -- " |
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"so only use it if you are *sure* you are running on this specific " |
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"SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!"); |
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MODULE_LICENSE("GPL");
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