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405 lines
9.8 KiB
405 lines
9.8 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* W83877F Computer Watchdog Timer driver |
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* |
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* Based on acquirewdt.c by Alan Cox, |
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* and sbc60xxwdt.c by Jakob Oestergaard <[email protected]> |
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* |
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* The authors do NOT admit liability nor provide warranty for |
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* any of this software. This material is provided "AS-IS" in |
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* the hope that it may be useful for others. |
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* |
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* (c) Copyright 2001 Scott Jennings <[email protected]> |
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* |
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* 4/19 - 2001 [Initial revision] |
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* 9/27 - 2001 Added spinlocking |
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* 4/12 - 2002 [[email protected]] Eliminate extra comments |
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* Eliminate fop_read |
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* Eliminate extra spin_unlock |
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* Added KERN_* tags to printks |
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* add CONFIG_WATCHDOG_NOWAYOUT support |
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* fix possible wdt_is_open race |
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* changed watchdog_info to correctly reflect what |
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* the driver offers |
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* added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS, |
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* WDIOC_SETTIMEOUT, |
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* WDIOC_GETTIMEOUT, and WDIOC_SETOPTIONS ioctls |
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* 09/8 - 2003 [[email protected]] cleanup of trailing spaces |
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* added extra printk's for startup problems |
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* use module_param |
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* made timeout (the emulated heartbeat) a |
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* module_param |
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* made the keepalive ping an internal subroutine |
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* |
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* This WDT driver is different from most other Linux WDT |
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* drivers in that the driver will ping the watchdog by itself, |
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* because this particular WDT has a very short timeout (1.6 |
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* seconds) and it would be insane to count on any userspace |
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* daemon always getting scheduled within that time frame. |
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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/timer.h> |
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#include <linux/jiffies.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/io.h> |
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#include <linux/uaccess.h> |
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#define OUR_NAME "w83877f_wdt" |
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#define ENABLE_W83877F_PORT 0x3F0 |
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#define ENABLE_W83877F 0x87 |
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#define DISABLE_W83877F 0xAA |
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#define WDT_PING 0x443 |
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#define WDT_REGISTER 0x14 |
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#define WDT_ENABLE 0x9C |
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#define WDT_DISABLE 0x8C |
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/* |
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* The W83877F seems to be fixed at 1.6s timeout (at least on the |
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* EMACS PC-104 board I'm using). If we reset the watchdog every |
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* ~250ms we should be safe. */ |
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#define WDT_INTERVAL (HZ/4+1) |
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/* |
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* We must not require too good response from the userspace daemon. |
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* Here we require the userspace daemon to send us a heartbeat |
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* char to /dev/watchdog every 30 seconds. |
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*/ |
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#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ |
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/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */ |
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static int timeout = WATCHDOG_TIMEOUT; |
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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<=3600, default=" |
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__MODULE_STRING(WATCHDOG_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, |
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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 wdt_timer_ping(struct timer_list *); |
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static DEFINE_TIMER(timer, wdt_timer_ping); |
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static unsigned long next_heartbeat; |
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static unsigned long wdt_is_open; |
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static char wdt_expect_close; |
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static DEFINE_SPINLOCK(wdt_spinlock); |
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/* |
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* Whack the dog |
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*/ |
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static void wdt_timer_ping(struct timer_list *unused) |
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{ |
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/* If we got a heartbeat pulse within the WDT_US_INTERVAL |
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* we agree to ping the WDT |
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*/ |
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if (time_before(jiffies, next_heartbeat)) { |
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/* Ping the WDT */ |
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spin_lock(&wdt_spinlock); |
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/* Ping the WDT by reading from WDT_PING */ |
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inb_p(WDT_PING); |
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/* Re-set the timer interval */ |
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mod_timer(&timer, jiffies + WDT_INTERVAL); |
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spin_unlock(&wdt_spinlock); |
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} else |
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pr_warn("Heartbeat lost! Will not ping the watchdog\n"); |
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} |
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/* |
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* Utility routines |
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*/ |
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static void wdt_change(int writeval) |
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{ |
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unsigned long flags; |
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spin_lock_irqsave(&wdt_spinlock, flags); |
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/* buy some time */ |
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inb_p(WDT_PING); |
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/* make W83877F available */ |
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outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); |
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outb_p(ENABLE_W83877F, ENABLE_W83877F_PORT); |
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/* enable watchdog */ |
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outb_p(WDT_REGISTER, ENABLE_W83877F_PORT); |
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outb_p(writeval, ENABLE_W83877F_PORT+1); |
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/* lock the W8387FF away */ |
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outb_p(DISABLE_W83877F, ENABLE_W83877F_PORT); |
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spin_unlock_irqrestore(&wdt_spinlock, flags); |
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} |
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static void wdt_startup(void) |
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{ |
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next_heartbeat = jiffies + (timeout * HZ); |
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/* Start the timer */ |
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mod_timer(&timer, jiffies + WDT_INTERVAL); |
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wdt_change(WDT_ENABLE); |
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pr_info("Watchdog timer is now enabled\n"); |
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} |
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static void wdt_turnoff(void) |
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{ |
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/* Stop the timer */ |
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del_timer_sync(&timer); |
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wdt_change(WDT_DISABLE); |
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pr_info("Watchdog timer is now disabled...\n"); |
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} |
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static void wdt_keepalive(void) |
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{ |
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/* user land ping */ |
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next_heartbeat = jiffies + (timeout * HZ); |
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} |
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/* |
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* /dev/watchdog handling |
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*/ |
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static ssize_t fop_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 ofs; |
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/* note: just in case someone wrote the magic |
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character five months ago... */ |
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wdt_expect_close = 0; |
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/* scan to see whether or not we got the |
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magic character */ |
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for (ofs = 0; ofs != count; ofs++) { |
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char c; |
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if (get_user(c, buf + ofs)) |
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return -EFAULT; |
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if (c == 'V') |
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wdt_expect_close = 42; |
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} |
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} |
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/* someone wrote to us, we should restart timer */ |
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wdt_keepalive(); |
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} |
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return count; |
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} |
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static int fop_open(struct inode *inode, struct file *file) |
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{ |
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/* Just in case we're already talking to someone... */ |
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if (test_and_set_bit(0, &wdt_is_open)) |
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return -EBUSY; |
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/* Good, fire up the show */ |
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wdt_startup(); |
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return stream_open(inode, file); |
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} |
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static int fop_close(struct inode *inode, struct file *file) |
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{ |
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if (wdt_expect_close == 42) |
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wdt_turnoff(); |
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else { |
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del_timer(&timer); |
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pr_crit("device file closed unexpectedly. Will not stop the WDT!\n"); |
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} |
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clear_bit(0, &wdt_is_open); |
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wdt_expect_close = 0; |
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return 0; |
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} |
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static long fop_ioctl(struct file *file, unsigned int cmd, 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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.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
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| WDIOF_MAGICCLOSE, |
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.firmware_version = 1, |
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.identity = "W83877F", |
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}; |
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switch (cmd) { |
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case WDIOC_GETSUPPORT: |
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return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
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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 new_options, retval = -EINVAL; |
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if (get_user(new_options, p)) |
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return -EFAULT; |
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if (new_options & WDIOS_DISABLECARD) { |
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wdt_turnoff(); |
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retval = 0; |
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} |
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if (new_options & WDIOS_ENABLECARD) { |
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wdt_startup(); |
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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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wdt_keepalive(); |
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return 0; |
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case WDIOC_SETTIMEOUT: |
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{ |
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int new_timeout; |
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if (get_user(new_timeout, p)) |
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return -EFAULT; |
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/* arbitrary upper limit */ |
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if (new_timeout < 1 || new_timeout > 3600) |
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return -EINVAL; |
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timeout = new_timeout; |
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wdt_keepalive(); |
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} |
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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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} |
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static const struct file_operations wdt_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.write = fop_write, |
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.open = fop_open, |
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.release = fop_close, |
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.unlocked_ioctl = fop_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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}; |
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static struct miscdevice wdt_miscdev = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &wdt_fops, |
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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 wdt_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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wdt_turnoff(); |
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return NOTIFY_DONE; |
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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 wdt_notifier = { |
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.notifier_call = wdt_notify_sys, |
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}; |
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static void __exit w83877f_wdt_unload(void) |
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{ |
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wdt_turnoff(); |
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/* Deregister */ |
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misc_deregister(&wdt_miscdev); |
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unregister_reboot_notifier(&wdt_notifier); |
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release_region(WDT_PING, 1); |
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release_region(ENABLE_W83877F_PORT, 2); |
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} |
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static int __init w83877f_wdt_init(void) |
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{ |
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int rc = -EBUSY; |
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if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */ |
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timeout = WATCHDOG_TIMEOUT; |
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pr_info("timeout value must be 1 <= x <= 3600, using %d\n", |
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timeout); |
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} |
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if (!request_region(ENABLE_W83877F_PORT, 2, "W83877F WDT")) { |
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pr_err("I/O address 0x%04x already in use\n", |
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ENABLE_W83877F_PORT); |
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rc = -EIO; |
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goto err_out; |
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} |
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if (!request_region(WDT_PING, 1, "W8387FF WDT")) { |
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pr_err("I/O address 0x%04x already in use\n", WDT_PING); |
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rc = -EIO; |
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goto err_out_region1; |
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} |
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rc = register_reboot_notifier(&wdt_notifier); |
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if (rc) { |
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pr_err("cannot register reboot notifier (err=%d)\n", rc); |
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goto err_out_region2; |
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} |
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rc = misc_register(&wdt_miscdev); |
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if (rc) { |
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pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
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wdt_miscdev.minor, rc); |
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goto err_out_reboot; |
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} |
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pr_info("WDT driver for W83877F initialised. timeout=%d sec (nowayout=%d)\n", |
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timeout, nowayout); |
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return 0; |
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err_out_reboot: |
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unregister_reboot_notifier(&wdt_notifier); |
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err_out_region2: |
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release_region(WDT_PING, 1); |
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err_out_region1: |
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release_region(ENABLE_W83877F_PORT, 2); |
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err_out: |
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return rc; |
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} |
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module_init(w83877f_wdt_init); |
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module_exit(w83877f_wdt_unload); |
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MODULE_AUTHOR("Scott and Bill Jennings"); |
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MODULE_DESCRIPTION("Driver for watchdog timer in w83877f chip"); |
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MODULE_LICENSE("GPL");
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