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404 lines
9.6 KiB
404 lines
9.6 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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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 <[email protected]> |
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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 <[email protected]> |
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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 <[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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* 14-Dec-2001 Matt Domsch <[email protected]> |
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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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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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 <linux/io.h> |
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#include <linux/uaccess.h> |
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static unsigned long sbc8360_is_open; |
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static char expect_close; |
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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 bool nowayout = WATCHDOG_NOWAYOUT; |
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module_param(timeout, int, 0); |
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MODULE_PARM_DESC(timeout, "Index into timeout table (0-63) (default=27 (60s))"); |
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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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/* |
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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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/* stop watchdog */ |
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static void sbc8360_stop(void) |
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{ |
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/* De-activate the watchdog */ |
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outb(0, SBC8360_ENABLE); |
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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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if (test_and_set_bit(0, &sbc8360_is_open)) |
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return -EBUSY; |
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if (nowayout) |
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__module_get(THIS_MODULE); |
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/* Activate and ping once to start the countdown */ |
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sbc8360_activate(); |
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sbc8360_ping(); |
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return stream_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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if (expect_close == 42) |
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sbc8360_stop(); |
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else |
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pr_crit("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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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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sbc8360_stop(); /* Disable the SBC8360 Watchdog */ |
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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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if (timeout < 0 || timeout > 63) { |
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pr_err("Invalid timeout index (must be 0-63)\n"); |
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res = -EINVAL; |
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goto out; |
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} |
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if (!request_region(SBC8360_ENABLE, 1, "SBC8360")) { |
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pr_err("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; |
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} |
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if (!request_region(SBC8360_BASETIME, 1, "SBC8360")) { |
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pr_err("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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pr_err("Failed to register reboot notifier\n"); |
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goto out_noreboot; |
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} |
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res = misc_register(&sbc8360_miscdev); |
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if (res) { |
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pr_err("failed to register misc device\n"); |
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goto out_nomisc; |
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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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pr_info("Timeout set at %ld ms\n", mseconds); |
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return 0; |
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out_nomisc: |
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unregister_reboot_notifier(&sbc8360_notifier); |
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out_noreboot: |
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release_region(SBC8360_BASETIME, 1); |
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out_nobasetimereg: |
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release_region(SBC8360_ENABLE, 1); |
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out: |
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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 <[email protected]>"); |
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MODULE_DESCRIPTION("SBC8360 watchdog driver"); |
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MODULE_LICENSE("GPL"); |
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MODULE_VERSION("1.01"); |
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/* end of sbc8360.c */
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