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263 lines
6.2 KiB
263 lines
6.2 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* drivers/char/watchdog/scx200_wdt.c |
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National Semiconductor SCx200 Watchdog support |
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Copyright (c) 2001,2002 Christer Weinigel <[email protected]> |
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Some code taken from: |
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National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver |
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(c) Copyright 2002 Zwane Mwaikambo <[email protected]> |
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The author(s) of this software shall not be held liable for damages |
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of any nature resulting due to the use of this software. This |
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software is provided AS-IS with no warranties. */ |
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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/init.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/fs.h> |
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#include <linux/ioport.h> |
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#include <linux/scx200.h> |
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#include <linux/uaccess.h> |
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#include <linux/io.h> |
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#define DEBUG |
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MODULE_AUTHOR("Christer Weinigel <[email protected]>"); |
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MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver"); |
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MODULE_LICENSE("GPL"); |
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static int margin = 60; /* in seconds */ |
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module_param(margin, int, 0); |
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MODULE_PARM_DESC(margin, "Watchdog margin in seconds"); |
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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, "Disable watchdog shutdown on close"); |
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static u16 wdto_restart; |
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static char expect_close; |
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static unsigned long open_lock; |
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static DEFINE_SPINLOCK(scx_lock); |
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/* Bits of the WDCNFG register */ |
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#define W_ENABLE 0x00fa /* Enable watchdog */ |
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#define W_DISABLE 0x0000 /* Disable watchdog */ |
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/* The scaling factor for the timer, this depends on the value of W_ENABLE */ |
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#define W_SCALE (32768/1024) |
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static void scx200_wdt_ping(void) |
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{ |
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spin_lock(&scx_lock); |
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outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO); |
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spin_unlock(&scx_lock); |
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} |
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static void scx200_wdt_update_margin(void) |
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{ |
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pr_info("timer margin %d seconds\n", margin); |
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wdto_restart = margin * W_SCALE; |
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} |
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static void scx200_wdt_enable(void) |
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{ |
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pr_debug("enabling watchdog timer, wdto_restart = %d\n", wdto_restart); |
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spin_lock(&scx_lock); |
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outw(0, scx200_cb_base + SCx200_WDT_WDTO); |
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outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS); |
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outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG); |
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spin_unlock(&scx_lock); |
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scx200_wdt_ping(); |
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} |
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static void scx200_wdt_disable(void) |
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{ |
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pr_debug("disabling watchdog timer\n"); |
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spin_lock(&scx_lock); |
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outw(0, scx200_cb_base + SCx200_WDT_WDTO); |
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outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS); |
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outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG); |
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spin_unlock(&scx_lock); |
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} |
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static int scx200_wdt_open(struct inode *inode, struct file *file) |
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{ |
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/* only allow one at a time */ |
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if (test_and_set_bit(0, &open_lock)) |
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return -EBUSY; |
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scx200_wdt_enable(); |
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return stream_open(inode, file); |
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} |
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static int scx200_wdt_release(struct inode *inode, struct file *file) |
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{ |
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if (expect_close != 42) |
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pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n"); |
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else if (!nowayout) |
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scx200_wdt_disable(); |
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expect_close = 0; |
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clear_bit(0, &open_lock); |
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return 0; |
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} |
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static int scx200_wdt_notify_sys(struct notifier_block *this, |
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unsigned long code, void *unused) |
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{ |
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if (code == SYS_HALT || code == SYS_POWER_OFF) |
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if (!nowayout) |
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scx200_wdt_disable(); |
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return NOTIFY_DONE; |
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} |
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static struct notifier_block scx200_wdt_notifier = { |
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.notifier_call = scx200_wdt_notify_sys, |
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}; |
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static ssize_t scx200_wdt_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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/* check for a magic close character */ |
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if (len) { |
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size_t i; |
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scx200_wdt_ping(); |
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expect_close = 0; |
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for (i = 0; i < len; ++i) { |
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char c; |
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if (get_user(c, data + 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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return len; |
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} |
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return 0; |
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} |
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static long scx200_wdt_ioctl(struct file *file, unsigned int cmd, |
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unsigned long arg) |
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{ |
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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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.identity = "NatSemi SCx200 Watchdog", |
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.firmware_version = 1, |
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
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WDIOF_MAGICCLOSE, |
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}; |
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int new_margin; |
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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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if (put_user(0, p)) |
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return -EFAULT; |
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return 0; |
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case WDIOC_KEEPALIVE: |
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scx200_wdt_ping(); |
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return 0; |
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case WDIOC_SETTIMEOUT: |
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if (get_user(new_margin, p)) |
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return -EFAULT; |
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if (new_margin < 1) |
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return -EINVAL; |
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margin = new_margin; |
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scx200_wdt_update_margin(); |
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scx200_wdt_ping(); |
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fallthrough; |
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case WDIOC_GETTIMEOUT: |
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if (put_user(margin, p)) |
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return -EFAULT; |
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return 0; |
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default: |
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return -ENOTTY; |
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} |
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} |
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static const struct file_operations scx200_wdt_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.write = scx200_wdt_write, |
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.unlocked_ioctl = scx200_wdt_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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.open = scx200_wdt_open, |
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.release = scx200_wdt_release, |
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}; |
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static struct miscdevice scx200_wdt_miscdev = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &scx200_wdt_fops, |
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}; |
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static int __init scx200_wdt_init(void) |
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{ |
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int r; |
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pr_debug("NatSemi SCx200 Watchdog Driver\n"); |
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/* check that we have found the configuration block */ |
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if (!scx200_cb_present()) |
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return -ENODEV; |
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if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET, |
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SCx200_WDT_SIZE, |
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"NatSemi SCx200 Watchdog")) { |
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pr_warn("watchdog I/O region busy\n"); |
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return -EBUSY; |
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} |
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scx200_wdt_update_margin(); |
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scx200_wdt_disable(); |
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r = register_reboot_notifier(&scx200_wdt_notifier); |
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if (r) { |
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pr_err("unable to register reboot notifier\n"); |
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release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
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SCx200_WDT_SIZE); |
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return r; |
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} |
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r = misc_register(&scx200_wdt_miscdev); |
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if (r) { |
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unregister_reboot_notifier(&scx200_wdt_notifier); |
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release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
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SCx200_WDT_SIZE); |
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return r; |
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} |
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return 0; |
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} |
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static void __exit scx200_wdt_cleanup(void) |
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{ |
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misc_deregister(&scx200_wdt_miscdev); |
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unregister_reboot_notifier(&scx200_wdt_notifier); |
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release_region(scx200_cb_base + SCx200_WDT_OFFSET, |
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SCx200_WDT_SIZE); |
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} |
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module_init(scx200_wdt_init); |
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module_exit(scx200_wdt_cleanup);
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