62322d2554
Mark the static struct file_operations in drivers/char as const. Making them const prevents accidental bugs, and moves them to the .rodata section so that they no longer do any false sharing; in addition with the proper debug option they are then protected against corruption.. [akpm@osdl.org: build fix] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
413 lines
10 KiB
C
413 lines
10 KiB
C
/*
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* SBC8360 Watchdog driver
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*
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* (c) Copyright 2005 Webcon, Inc.
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*
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* Based on ib700wdt.c, which is based on advantechwdt.c which is based
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* on acquirewdt.c which is based on wdt.c.
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*
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* (c) Copyright 2001 Charles Howes <chowes@vsol.net>
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*
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* Based on advantechwdt.c which is based on acquirewdt.c which
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* is based on wdt.c.
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*
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* (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
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*
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* Based on acquirewdt.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 Alan Cox <alan@redhat.com>, All Rights Reserved.
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* http://www.redhat.com
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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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 <alan@redhat.com>
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*
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* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
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* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
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* Added timeout module option to override default
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*
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/ioport.h>
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#include <linux/delay.h>
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#include <linux/notifier.h>
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#include <linux/fs.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/moduleparam.h>
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#include <asm/io.h>
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#include <asm/uaccess.h>
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#include <asm/system.h>
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static unsigned long sbc8360_is_open;
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static spinlock_t sbc8360_lock;
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static char expect_close;
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#define PFX "sbc8360: "
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/*
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*
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* Watchdog Timer Configuration
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*
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* The function of the watchdog timer is to reset the system automatically
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* and is defined at I/O port 0120H and 0121H. To enable the watchdog timer
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* and allow the system to reset, write appropriate values from the table
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* below to I/O port 0120H and 0121H. To disable the timer, write a zero
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* value to I/O port 0121H for the system to stop the watchdog function.
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*
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* The following describes how the timer should be programmed (according to
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* the vendor documentation)
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*
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* Enabling Watchdog:
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* MOV AX,000AH (enable, phase I)
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* MOV DX,0120H
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* OUT DX,AX
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* MOV AX,000BH (enable, phase II)
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* MOV DX,0120H
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* OUT DX,AX
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* MOV AX,000nH (set multiplier n, from 1-4)
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* MOV DX,0120H
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* OUT DX,AX
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* MOV AX,000mH (set base timer m, from 0-F)
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* MOV DX,0121H
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* OUT DX,AX
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*
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* Reset timer:
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* MOV AX,000mH (same as set base timer, above)
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* MOV DX,0121H
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* OUT DX,AX
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*
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* Disabling Watchdog:
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* MOV AX,0000H (a zero value)
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* MOV DX,0120H
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* OUT DX,AX
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*
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* Watchdog timeout configuration values:
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* N
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* M | 1 2 3 4
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* --|----------------------------------
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* 0 | 0.5s 5s 50s 100s
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* 1 | 1s 10s 100s 200s
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* 2 | 1.5s 15s 150s 300s
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* 3 | 2s 20s 200s 400s
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* 4 | 2.5s 25s 250s 500s
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* 5 | 3s 30s 300s 600s
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* 6 | 3.5s 35s 350s 700s
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* 7 | 4s 40s 400s 800s
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* 8 | 4.5s 45s 450s 900s
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* 9 | 5s 50s 500s 1000s
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* A | 5.5s 55s 550s 1100s
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* B | 6s 60s 600s 1200s
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* C | 6.5s 65s 650s 1300s
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* D | 7s 70s 700s 1400s
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* E | 7.5s 75s 750s 1500s
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* F | 8s 80s 800s 1600s
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*
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* Another way to say the same things is:
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* For N=1, Timeout = (M+1) * 0.5s
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* For N=2, Timeout = (M+1) * 5s
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* For N=3, Timeout = (M+1) * 50s
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* For N=4, Timeout = (M+1) * 100s
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*
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*/
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static int wd_times[64][2] = {
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{0, 1}, /* 0 = 0.5s */
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{1, 1}, /* 1 = 1s */
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{2, 1}, /* 2 = 1.5s */
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{3, 1}, /* 3 = 2s */
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{4, 1}, /* 4 = 2.5s */
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{5, 1}, /* 5 = 3s */
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{6, 1}, /* 6 = 3.5s */
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{7, 1}, /* 7 = 4s */
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{8, 1}, /* 8 = 4.5s */
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{9, 1}, /* 9 = 5s */
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{0xA, 1}, /* 10 = 5.5s */
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{0xB, 1}, /* 11 = 6s */
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{0xC, 1}, /* 12 = 6.5s */
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{0xD, 1}, /* 13 = 7s */
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{0xE, 1}, /* 14 = 7.5s */
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{0xF, 1}, /* 15 = 8s */
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{0, 2}, /* 16 = 5s */
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{1, 2}, /* 17 = 10s */
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{2, 2}, /* 18 = 15s */
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{3, 2}, /* 19 = 20s */
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{4, 2}, /* 20 = 25s */
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{5, 2}, /* 21 = 30s */
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{6, 2}, /* 22 = 35s */
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{7, 2}, /* 23 = 40s */
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{8, 2}, /* 24 = 45s */
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{9, 2}, /* 25 = 50s */
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{0xA, 2}, /* 26 = 55s */
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{0xB, 2}, /* 27 = 60s */
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{0xC, 2}, /* 28 = 65s */
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{0xD, 2}, /* 29 = 70s */
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{0xE, 2}, /* 30 = 75s */
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{0xF, 2}, /* 31 = 80s */
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{0, 3}, /* 32 = 50s */
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{1, 3}, /* 33 = 100s */
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{2, 3}, /* 34 = 150s */
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{3, 3}, /* 35 = 200s */
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{4, 3}, /* 36 = 250s */
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{5, 3}, /* 37 = 300s */
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{6, 3}, /* 38 = 350s */
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{7, 3}, /* 39 = 400s */
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{8, 3}, /* 40 = 450s */
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{9, 3}, /* 41 = 500s */
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{0xA, 3}, /* 42 = 550s */
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{0xB, 3}, /* 43 = 600s */
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{0xC, 3}, /* 44 = 650s */
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{0xD, 3}, /* 45 = 700s */
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{0xE, 3}, /* 46 = 750s */
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{0xF, 3}, /* 47 = 800s */
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{0, 4}, /* 48 = 100s */
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{1, 4}, /* 49 = 200s */
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{2, 4}, /* 50 = 300s */
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{3, 4}, /* 51 = 400s */
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{4, 4}, /* 52 = 500s */
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{5, 4}, /* 53 = 600s */
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{6, 4}, /* 54 = 700s */
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{7, 4}, /* 55 = 800s */
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{8, 4}, /* 56 = 900s */
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{9, 4}, /* 57 = 1000s */
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{0xA, 4}, /* 58 = 1100s */
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{0xB, 4}, /* 59 = 1200s */
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{0xC, 4}, /* 60 = 1300s */
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{0xD, 4}, /* 61 = 1400s */
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{0xE, 4}, /* 62 = 1500s */
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{0xF, 4} /* 63 = 1600s */
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};
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#define SBC8360_ENABLE 0x120
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#define SBC8360_BASETIME 0x121
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static int timeout = 27;
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static int wd_margin = 0xB;
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static int wd_multiplier = 2;
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static int nowayout = WATCHDOG_NOWAYOUT;
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module_param(timeout, int, 27);
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MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))");
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout,
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"Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
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/*
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* Kernel methods.
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*/
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/* Activate and pre-configure watchdog */
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static void sbc8360_activate(void)
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{
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/* Enable the watchdog */
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outb(0x0A, SBC8360_ENABLE);
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msleep_interruptible(100);
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outb(0x0B, SBC8360_ENABLE);
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msleep_interruptible(100);
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/* Set timeout multiplier */
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outb(wd_multiplier, SBC8360_ENABLE);
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msleep_interruptible(100);
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/* Nothing happens until first sbc8360_ping() */
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}
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/* Kernel pings watchdog */
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static void sbc8360_ping(void)
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{
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/* Write the base timer register */
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outb(wd_margin, SBC8360_BASETIME);
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}
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/* Userspace pings kernel driver, or requests clean close */
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static ssize_t sbc8360_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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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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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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sbc8360_ping();
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}
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return count;
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}
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static int sbc8360_open(struct inode *inode, struct file *file)
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{
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spin_lock(&sbc8360_lock);
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if (test_and_set_bit(0, &sbc8360_is_open)) {
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spin_unlock(&sbc8360_lock);
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return -EBUSY;
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}
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if (nowayout)
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__module_get(THIS_MODULE);
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/* Activate and ping once to start the countdown */
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spin_unlock(&sbc8360_lock);
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sbc8360_activate();
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sbc8360_ping();
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return nonseekable_open(inode, file);
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}
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static int sbc8360_close(struct inode *inode, struct file *file)
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{
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spin_lock(&sbc8360_lock);
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if (expect_close == 42)
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outb(0, SBC8360_ENABLE);
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else
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printk(KERN_CRIT PFX
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"SBC8360 device closed unexpectedly. SBC8360 will not stop!\n");
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clear_bit(0, &sbc8360_is_open);
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expect_close = 0;
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spin_unlock(&sbc8360_lock);
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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 sbc8360_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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/* Disable the SBC8360 Watchdog */
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outb(0, SBC8360_ENABLE);
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}
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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 sbc8360_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = sbc8360_write,
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.open = sbc8360_open,
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.release = sbc8360_close,
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};
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static struct miscdevice sbc8360_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &sbc8360_fops,
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};
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/*
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* The SBC8360 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 sbc8360_notifier = {
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.notifier_call = sbc8360_notify_sys,
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};
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static int __init sbc8360_init(void)
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{
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int res;
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unsigned long int mseconds = 60000;
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spin_lock_init(&sbc8360_lock);
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res = misc_register(&sbc8360_miscdev);
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if (res) {
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printk(KERN_ERR PFX "failed to register misc device\n");
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goto out_nomisc;
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}
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if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) {
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printk(KERN_ERR PFX "ENABLE method I/O %X is not available.\n",
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SBC8360_ENABLE);
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res = -EIO;
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goto out_noenablereg;
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}
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if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) {
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printk(KERN_ERR PFX
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"BASETIME method I/O %X is not available.\n",
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SBC8360_BASETIME);
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res = -EIO;
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goto out_nobasetimereg;
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}
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res = register_reboot_notifier(&sbc8360_notifier);
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if (res) {
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printk(KERN_ERR PFX "Failed to register reboot notifier.\n");
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goto out_noreboot;
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}
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if (timeout < 0 || timeout > 63) {
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printk(KERN_ERR PFX "Invalid timeout index (must be 0-63).\n");
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res = -EINVAL;
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goto out_noreboot;
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}
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wd_margin = wd_times[timeout][0];
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wd_multiplier = wd_times[timeout][1];
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if (wd_multiplier == 1)
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mseconds = (wd_margin + 1) * 500;
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else if (wd_multiplier == 2)
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mseconds = (wd_margin + 1) * 5000;
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else if (wd_multiplier == 3)
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mseconds = (wd_margin + 1) * 50000;
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else if (wd_multiplier == 4)
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mseconds = (wd_margin + 1) * 100000;
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/* My kingdom for the ability to print "0.5 seconds" in the kernel! */
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printk(KERN_INFO PFX "Timeout set at %ld ms.\n", mseconds);
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return 0;
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out_noreboot:
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release_region(SBC8360_ENABLE, 1);
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release_region(SBC8360_BASETIME, 1);
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out_noenablereg:
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out_nobasetimereg:
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misc_deregister(&sbc8360_miscdev);
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out_nomisc:
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return res;
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}
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static void __exit sbc8360_exit(void)
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{
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misc_deregister(&sbc8360_miscdev);
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unregister_reboot_notifier(&sbc8360_notifier);
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release_region(SBC8360_ENABLE, 1);
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release_region(SBC8360_BASETIME, 1);
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}
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module_init(sbc8360_init);
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module_exit(sbc8360_exit);
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MODULE_AUTHOR("Ian E. Morgan <imorgan@webcon.ca>");
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MODULE_DESCRIPTION("SBC8360 watchdog driver");
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MODULE_LICENSE("GPL");
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MODULE_VERSION("1.0");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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/* end of sbc8360.c */
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