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323 lines
6.9 KiB
323 lines
6.9 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* ICP Wafer 5823 Single Board Computer WDT driver |
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* http://www.icpamerica.com/wafer_5823.php |
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* May also work on other similar models |
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* |
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* (c) Copyright 2002 Justin Cormack <[email protected]> |
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* |
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* Release 0.02 |
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* |
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* Based on advantechwdt.c which is based on wdt.c. |
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* Original copyright messages: |
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* |
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* (c) Copyright 1996-1997 Alan Cox <[email protected]>, |
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* All Rights Reserved. |
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* |
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* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide |
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* warranty for any of this software. This material is provided |
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* "AS-IS" and at no charge. |
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* |
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* (c) Copyright 1995 Alan Cox <[email protected]> |
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* |
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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/miscdevice.h> |
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#include <linux/watchdog.h> |
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#include <linux/fs.h> |
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#include <linux/ioport.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/spinlock.h> |
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#include <linux/io.h> |
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#include <linux/uaccess.h> |
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#define WATCHDOG_NAME "Wafer 5823 WDT" |
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#define PFX WATCHDOG_NAME ": " |
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#define WD_TIMO 60 /* 60 sec default timeout */ |
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static unsigned long wafwdt_is_open; |
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static char expect_close; |
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static DEFINE_SPINLOCK(wafwdt_lock); |
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/* |
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* You must set these - there is no sane way to probe for this board. |
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* |
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* To enable, write the timeout value in seconds (1 to 255) to I/O |
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* port WDT_START, then read the port to start the watchdog. To pat |
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* the dog, read port WDT_STOP to stop the timer, then read WDT_START |
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* to restart it again. |
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*/ |
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static int wdt_stop = 0x843; |
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static int wdt_start = 0x443; |
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static int timeout = WD_TIMO; /* in seconds */ |
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module_param(timeout, int, 0); |
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MODULE_PARM_DESC(timeout, |
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"Watchdog timeout in seconds. 1 <= timeout <= 255, default=" |
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__MODULE_STRING(WD_TIMO) "."); |
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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, |
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"Watchdog cannot be stopped once started (default=" |
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
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static void wafwdt_ping(void) |
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{ |
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/* pat watchdog */ |
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spin_lock(&wafwdt_lock); |
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inb_p(wdt_stop); |
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inb_p(wdt_start); |
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spin_unlock(&wafwdt_lock); |
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} |
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static void wafwdt_start(void) |
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{ |
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/* start up watchdog */ |
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outb_p(timeout, wdt_start); |
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inb_p(wdt_start); |
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} |
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static void wafwdt_stop(void) |
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{ |
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/* stop watchdog */ |
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inb_p(wdt_stop); |
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} |
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static ssize_t wafwdt_write(struct file *file, const char __user *buf, |
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size_t count, loff_t *ppos) |
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{ |
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/* See if we got the magic character 'V' and reload the timer */ |
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if (count) { |
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if (!nowayout) { |
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size_t i; |
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/* In case it was set long ago */ |
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expect_close = 0; |
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/* scan to see whether or not we got the magic |
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character */ |
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for (i = 0; i != count; i++) { |
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char c; |
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if (get_user(c, buf + i)) |
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return -EFAULT; |
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if (c == 'V') |
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expect_close = 42; |
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} |
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} |
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/* Well, anyhow someone wrote to us, we should |
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return that favour */ |
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wafwdt_ping(); |
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} |
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return count; |
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} |
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static long wafwdt_ioctl(struct file *file, unsigned int cmd, |
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unsigned long arg) |
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{ |
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int new_timeout; |
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void __user *argp = (void __user *)arg; |
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int __user *p = argp; |
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static const struct watchdog_info ident = { |
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.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | |
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WDIOF_MAGICCLOSE, |
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.firmware_version = 1, |
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.identity = "Wafer 5823 WDT", |
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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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break; |
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case WDIOC_GETSTATUS: |
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case WDIOC_GETBOOTSTATUS: |
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return put_user(0, p); |
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case WDIOC_SETOPTIONS: |
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{ |
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int options, retval = -EINVAL; |
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if (get_user(options, p)) |
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return -EFAULT; |
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if (options & WDIOS_DISABLECARD) { |
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wafwdt_stop(); |
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retval = 0; |
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} |
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if (options & WDIOS_ENABLECARD) { |
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wafwdt_start(); |
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retval = 0; |
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} |
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return retval; |
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} |
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case WDIOC_KEEPALIVE: |
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wafwdt_ping(); |
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break; |
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case WDIOC_SETTIMEOUT: |
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if (get_user(new_timeout, p)) |
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return -EFAULT; |
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if ((new_timeout < 1) || (new_timeout > 255)) |
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return -EINVAL; |
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timeout = new_timeout; |
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wafwdt_stop(); |
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wafwdt_start(); |
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fallthrough; |
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case WDIOC_GETTIMEOUT: |
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return put_user(timeout, p); |
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default: |
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return -ENOTTY; |
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} |
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return 0; |
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} |
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static int wafwdt_open(struct inode *inode, struct file *file) |
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{ |
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if (test_and_set_bit(0, &wafwdt_is_open)) |
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return -EBUSY; |
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/* |
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* Activate |
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*/ |
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wafwdt_start(); |
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return stream_open(inode, file); |
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} |
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static int wafwdt_close(struct inode *inode, struct file *file) |
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{ |
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if (expect_close == 42) |
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wafwdt_stop(); |
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else { |
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pr_crit("WDT device closed unexpectedly. WDT will not stop!\n"); |
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wafwdt_ping(); |
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} |
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clear_bit(0, &wafwdt_is_open); |
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expect_close = 0; |
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return 0; |
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} |
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/* |
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* Notifier for system down |
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*/ |
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static int wafwdt_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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wafwdt_stop(); |
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return NOTIFY_DONE; |
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} |
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/* |
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* Kernel Interfaces |
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*/ |
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static const struct file_operations wafwdt_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.write = wafwdt_write, |
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.unlocked_ioctl = wafwdt_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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.open = wafwdt_open, |
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.release = wafwdt_close, |
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}; |
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static struct miscdevice wafwdt_miscdev = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &wafwdt_fops, |
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}; |
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/* |
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* The WDT needs to learn about soft shutdowns in order to |
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* turn the timebomb registers off. |
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*/ |
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static struct notifier_block wafwdt_notifier = { |
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.notifier_call = wafwdt_notify_sys, |
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}; |
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static int __init wafwdt_init(void) |
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{ |
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int ret; |
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pr_info("WDT driver for Wafer 5823 single board computer initialising\n"); |
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if (timeout < 1 || timeout > 255) { |
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timeout = WD_TIMO; |
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pr_info("timeout value must be 1 <= x <= 255, using %d\n", |
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timeout); |
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} |
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if (wdt_stop != wdt_start) { |
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if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) { |
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pr_err("I/O address 0x%04x already in use\n", wdt_stop); |
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ret = -EIO; |
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goto error; |
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} |
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} |
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if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) { |
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pr_err("I/O address 0x%04x already in use\n", wdt_start); |
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ret = -EIO; |
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goto error2; |
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} |
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ret = register_reboot_notifier(&wafwdt_notifier); |
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if (ret != 0) { |
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pr_err("cannot register reboot notifier (err=%d)\n", ret); |
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goto error3; |
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} |
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ret = misc_register(&wafwdt_miscdev); |
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if (ret != 0) { |
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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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goto error4; |
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} |
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pr_info("initialized. timeout=%d sec (nowayout=%d)\n", |
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timeout, nowayout); |
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return ret; |
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error4: |
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unregister_reboot_notifier(&wafwdt_notifier); |
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error3: |
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release_region(wdt_start, 1); |
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error2: |
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if (wdt_stop != wdt_start) |
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release_region(wdt_stop, 1); |
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error: |
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return ret; |
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} |
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static void __exit wafwdt_exit(void) |
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{ |
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misc_deregister(&wafwdt_miscdev); |
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unregister_reboot_notifier(&wafwdt_notifier); |
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if (wdt_stop != wdt_start) |
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release_region(wdt_stop, 1); |
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release_region(wdt_start, 1); |
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} |
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module_init(wafwdt_init); |
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module_exit(wafwdt_exit); |
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MODULE_AUTHOR("Justin Cormack"); |
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MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver"); |
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MODULE_LICENSE("GPL"); |
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/* end of wafer5823wdt.c */
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