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615 lines
15 KiB
615 lines
15 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* SMsC 37B787 Watchdog Timer driver for Linux 2.6.x.x |
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* |
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* Based on acquirewdt.c by Alan Cox <[email protected]> |
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* and some other existing drivers |
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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 2003-2006 Sven Anders <[email protected]> |
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* |
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* History: |
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* 2003 - Created version 1.0 for Linux 2.4.x. |
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* 2006 - Ported to Linux 2.6, added nowayout and MAGICCLOSE |
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* features. Released version 1.1 |
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* |
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* Theory of operation: |
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* |
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* A Watchdog Timer (WDT) is a hardware circuit that can |
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* reset the computer system in case of a software fault. |
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* You probably knew that already. |
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* |
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* Usually a userspace daemon will notify the kernel WDT driver |
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* via the /dev/watchdog special device file that userspace is |
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* still alive, at regular intervals. When such a notification |
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* occurs, the driver will usually tell the hardware watchdog |
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* that everything is in order, and that the watchdog should wait |
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* for yet another little while to reset the system. |
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* If userspace fails (RAM error, kernel bug, whatever), the |
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* notifications cease to occur, and the hardware watchdog will |
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* reset the system (causing a reboot) after the timeout occurs. |
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* |
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* Create device with: |
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* mknod /dev/watchdog c 10 130 |
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* |
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* For an example userspace keep-alive daemon, see: |
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* Documentation/watchdog/wdt.rst |
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*/ |
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|
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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|
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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/miscdevice.h> |
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#include <linux/watchdog.h> |
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#include <linux/delay.h> |
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#include <linux/fs.h> |
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#include <linux/ioport.h> |
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#include <linux/notifier.h> |
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#include <linux/reboot.h> |
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#include <linux/init.h> |
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#include <linux/spinlock.h> |
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#include <linux/io.h> |
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#include <linux/uaccess.h> |
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/* enable support for minutes as units? */ |
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/* (does not always work correctly, so disabled by default!) */ |
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#define SMSC_SUPPORT_MINUTES |
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#undef SMSC_SUPPORT_MINUTES |
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#define MAX_TIMEOUT 255 |
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#define UNIT_SECOND 0 |
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#define UNIT_MINUTE 1 |
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#define VERSION "1.1" |
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#define IOPORT 0x3F0 |
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#define IOPORT_SIZE 2 |
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#define IODEV_NO 8 |
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static int unit = UNIT_SECOND; /* timer's unit */ |
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static int timeout = 60; /* timeout value: default is 60 "units" */ |
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static unsigned long timer_enabled; /* is the timer enabled? */ |
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|
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static char expect_close; /* is the close expected? */ |
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static DEFINE_SPINLOCK(io_lock);/* to guard the watchdog from io races */ |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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|
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/* -- Low level function ----------------------------------------*/ |
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|
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/* unlock the IO chip */ |
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static inline void open_io_config(void) |
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{ |
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outb(0x55, IOPORT); |
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mdelay(1); |
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outb(0x55, IOPORT); |
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} |
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|
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/* lock the IO chip */ |
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static inline void close_io_config(void) |
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{ |
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outb(0xAA, IOPORT); |
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} |
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/* select the IO device */ |
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static inline void select_io_device(unsigned char devno) |
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{ |
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outb(0x07, IOPORT); |
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outb(devno, IOPORT+1); |
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} |
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/* write to the control register */ |
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static inline void write_io_cr(unsigned char reg, unsigned char data) |
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{ |
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outb(reg, IOPORT); |
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outb(data, IOPORT+1); |
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} |
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/* read from the control register */ |
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static inline char read_io_cr(unsigned char reg) |
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{ |
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outb(reg, IOPORT); |
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return inb(IOPORT+1); |
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} |
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/* -- Medium level functions ------------------------------------*/ |
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static inline void gpio_bit12(unsigned char reg) |
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{ |
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/* -- General Purpose I/O Bit 1.2 -- |
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* Bit 0, In/Out: 0 = Output, 1 = Input |
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* Bit 1, Polarity: 0 = No Invert, 1 = Invert |
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* Bit 2, Group Enable Intr.: 0 = Disable, 1 = Enable |
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* Bit 3/4, Function select: 00 = GPI/O, 01 = WDT, 10 = P17, |
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* 11 = Either Edge Triggered Intr. 2 |
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* Bit 5/6 (Reserved) |
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* Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain |
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*/ |
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write_io_cr(0xE2, reg); |
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} |
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static inline void gpio_bit13(unsigned char reg) |
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{ |
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/* -- General Purpose I/O Bit 1.3 -- |
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* Bit 0, In/Out: 0 = Output, 1 = Input |
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* Bit 1, Polarity: 0 = No Invert, 1 = Invert |
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* Bit 2, Group Enable Intr.: 0 = Disable, 1 = Enable |
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* Bit 3, Function select: 0 = GPI/O, 1 = LED |
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* Bit 4-6 (Reserved) |
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* Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain |
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*/ |
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write_io_cr(0xE3, reg); |
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} |
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static inline void wdt_timer_units(unsigned char new_units) |
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{ |
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/* -- Watchdog timer units -- |
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* Bit 0-6 (Reserved) |
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* Bit 7, WDT Time-out Value Units Select |
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* (0 = Minutes, 1 = Seconds) |
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*/ |
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write_io_cr(0xF1, new_units); |
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} |
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static inline void wdt_timeout_value(unsigned char new_timeout) |
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{ |
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/* -- Watchdog Timer Time-out Value -- |
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* Bit 0-7 Binary coded units (0=Disabled, 1..255) |
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*/ |
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write_io_cr(0xF2, new_timeout); |
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} |
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static inline void wdt_timer_conf(unsigned char conf) |
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{ |
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/* -- Watchdog timer configuration -- |
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* Bit 0 Joystick enable: 0* = No Reset, 1 = Reset WDT upon |
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* Gameport I/O |
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* Bit 1 Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr. |
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* Bit 2 Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr |
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* Bit 3 Reset the timer |
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* (Wrong in SMsC documentation? Given as: PowerLED Timout |
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* Enabled) |
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* Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled, |
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* 0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15) |
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*/ |
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write_io_cr(0xF3, conf); |
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} |
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static inline void wdt_timer_ctrl(unsigned char reg) |
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{ |
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/* -- Watchdog timer control -- |
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* Bit 0 Status Bit: 0 = Timer counting, 1 = Timeout occurred |
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* Bit 1 Power LED Toggle: 0 = Disable Toggle, 1 = Toggle at 1 Hz |
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* Bit 2 Force Timeout: 1 = Forces WD timeout event (self-cleaning) |
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* Bit 3 P20 Force Timeout enabled: |
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* 0 = P20 activity does not generate the WD timeout event |
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* 1 = P20 Allows rising edge of P20, from the keyboard |
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* controller, to force the WD timeout event. |
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* Bit 4 (Reserved) |
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* -- Soft power management -- |
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* Bit 5 Stop Counter: 1 = Stop software power down counter |
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* set via register 0xB8, (self-cleaning) |
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* (Upon read: 0 = Counter running, 1 = Counter stopped) |
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* Bit 6 Restart Counter: 1 = Restart software power down counter |
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* set via register 0xB8, (self-cleaning) |
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* Bit 7 SPOFF: 1 = Force software power down (self-cleaning) |
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*/ |
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write_io_cr(0xF4, reg); |
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} |
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/* -- Higher level functions ------------------------------------*/ |
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/* initialize watchdog */ |
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static void wb_smsc_wdt_initialize(void) |
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{ |
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unsigned char old; |
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spin_lock(&io_lock); |
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open_io_config(); |
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select_io_device(IODEV_NO); |
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/* enable the watchdog */ |
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gpio_bit13(0x08); /* Select pin 80 = LED not GPIO */ |
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gpio_bit12(0x0A); /* Set pin 79 = WDT not |
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GPIO/Output/Polarity=Invert */ |
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/* disable the timeout */ |
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wdt_timeout_value(0); |
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/* reset control register */ |
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wdt_timer_ctrl(0x00); |
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/* reset configuration register */ |
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wdt_timer_conf(0x00); |
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/* read old (timer units) register */ |
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old = read_io_cr(0xF1) & 0x7F; |
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if (unit == UNIT_SECOND) |
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old |= 0x80; /* set to seconds */ |
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/* set the watchdog timer units */ |
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wdt_timer_units(old); |
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close_io_config(); |
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spin_unlock(&io_lock); |
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} |
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/* shutdown the watchdog */ |
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static void wb_smsc_wdt_shutdown(void) |
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{ |
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spin_lock(&io_lock); |
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open_io_config(); |
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select_io_device(IODEV_NO); |
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/* disable the watchdog */ |
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gpio_bit13(0x09); |
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gpio_bit12(0x09); |
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/* reset watchdog config register */ |
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wdt_timer_conf(0x00); |
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/* reset watchdog control register */ |
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wdt_timer_ctrl(0x00); |
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/* disable timeout */ |
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wdt_timeout_value(0x00); |
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close_io_config(); |
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spin_unlock(&io_lock); |
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} |
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/* set timeout => enable watchdog */ |
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static void wb_smsc_wdt_set_timeout(unsigned char new_timeout) |
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{ |
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spin_lock(&io_lock); |
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open_io_config(); |
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select_io_device(IODEV_NO); |
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/* set Power LED to blink, if we enable the timeout */ |
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wdt_timer_ctrl((new_timeout == 0) ? 0x00 : 0x02); |
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/* set timeout value */ |
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wdt_timeout_value(new_timeout); |
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close_io_config(); |
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spin_unlock(&io_lock); |
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} |
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/* get timeout */ |
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static unsigned char wb_smsc_wdt_get_timeout(void) |
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{ |
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unsigned char set_timeout; |
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spin_lock(&io_lock); |
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open_io_config(); |
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select_io_device(IODEV_NO); |
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set_timeout = read_io_cr(0xF2); |
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close_io_config(); |
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spin_unlock(&io_lock); |
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return set_timeout; |
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} |
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/* disable watchdog */ |
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static void wb_smsc_wdt_disable(void) |
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{ |
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/* set the timeout to 0 to disable the watchdog */ |
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wb_smsc_wdt_set_timeout(0); |
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} |
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/* enable watchdog by setting the current timeout */ |
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static void wb_smsc_wdt_enable(void) |
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{ |
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/* set the current timeout... */ |
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wb_smsc_wdt_set_timeout(timeout); |
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} |
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/* reset the timer */ |
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static void wb_smsc_wdt_reset_timer(void) |
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{ |
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spin_lock(&io_lock); |
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open_io_config(); |
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select_io_device(IODEV_NO); |
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/* reset the timer */ |
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wdt_timeout_value(timeout); |
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wdt_timer_conf(0x08); |
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close_io_config(); |
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spin_unlock(&io_lock); |
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} |
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/* return, if the watchdog is enabled (timeout is set...) */ |
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static int wb_smsc_wdt_status(void) |
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{ |
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return (wb_smsc_wdt_get_timeout() == 0) ? 0 : WDIOF_KEEPALIVEPING; |
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} |
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/* -- File operations -------------------------------------------*/ |
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/* open => enable watchdog and set initial timeout */ |
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static int wb_smsc_wdt_open(struct inode *inode, struct file *file) |
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{ |
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/* /dev/watchdog can only be opened once */ |
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if (test_and_set_bit(0, &timer_enabled)) |
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return -EBUSY; |
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if (nowayout) |
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__module_get(THIS_MODULE); |
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/* Reload and activate timer */ |
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wb_smsc_wdt_enable(); |
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pr_info("Watchdog enabled. Timeout set to %d %s\n", |
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timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)"); |
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return stream_open(inode, file); |
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} |
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/* close => shut off the timer */ |
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static int wb_smsc_wdt_release(struct inode *inode, struct file *file) |
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{ |
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/* Shut off the timer. */ |
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if (expect_close == 42) { |
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wb_smsc_wdt_disable(); |
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pr_info("Watchdog disabled, sleeping again...\n"); |
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} else { |
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pr_crit("Unexpected close, not stopping watchdog!\n"); |
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wb_smsc_wdt_reset_timer(); |
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} |
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clear_bit(0, &timer_enabled); |
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expect_close = 0; |
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return 0; |
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} |
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/* write => update the timer to keep the machine alive */ |
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static ssize_t wb_smsc_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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/* See if we got the magic character 'V' and reload the timer */ |
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if (len) { |
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if (!nowayout) { |
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size_t i; |
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/* reset expect flag */ |
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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 (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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} |
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/* someone wrote to us, we should reload the timer */ |
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wb_smsc_wdt_reset_timer(); |
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} |
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return len; |
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} |
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/* ioctl => control interface */ |
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static long wb_smsc_wdt_ioctl(struct file *file, |
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unsigned int cmd, unsigned long arg) |
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{ |
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int new_timeout; |
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union { |
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struct watchdog_info __user *ident; |
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int __user *i; |
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} uarg; |
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static const struct watchdog_info ident = { |
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.options = WDIOF_KEEPALIVEPING | |
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WDIOF_SETTIMEOUT | |
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WDIOF_MAGICCLOSE, |
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.firmware_version = 0, |
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.identity = "SMsC 37B787 Watchdog", |
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}; |
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uarg.i = (int __user *)arg; |
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switch (cmd) { |
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case WDIOC_GETSUPPORT: |
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return copy_to_user(uarg.ident, &ident, sizeof(ident)) |
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? -EFAULT : 0; |
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case WDIOC_GETSTATUS: |
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return put_user(wb_smsc_wdt_status(), uarg.i); |
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case WDIOC_GETBOOTSTATUS: |
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return put_user(0, uarg.i); |
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case WDIOC_SETOPTIONS: |
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{ |
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int options, retval = -EINVAL; |
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if (get_user(options, uarg.i)) |
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return -EFAULT; |
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if (options & WDIOS_DISABLECARD) { |
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wb_smsc_wdt_disable(); |
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retval = 0; |
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} |
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if (options & WDIOS_ENABLECARD) { |
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wb_smsc_wdt_enable(); |
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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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wb_smsc_wdt_reset_timer(); |
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return 0; |
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case WDIOC_SETTIMEOUT: |
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if (get_user(new_timeout, uarg.i)) |
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return -EFAULT; |
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/* the API states this is given in secs */ |
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if (unit == UNIT_MINUTE) |
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new_timeout /= 60; |
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if (new_timeout < 0 || new_timeout > MAX_TIMEOUT) |
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return -EINVAL; |
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timeout = new_timeout; |
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wb_smsc_wdt_set_timeout(timeout); |
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fallthrough; /* and return the new timeout */ |
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case WDIOC_GETTIMEOUT: |
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new_timeout = timeout; |
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if (unit == UNIT_MINUTE) |
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new_timeout *= 60; |
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return put_user(new_timeout, uarg.i); |
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default: |
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return -ENOTTY; |
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} |
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} |
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/* -- Notifier funtions -----------------------------------------*/ |
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static int wb_smsc_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_DOWN || code == SYS_HALT) { |
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/* set timeout to 0, to avoid possible race-condition */ |
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timeout = 0; |
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wb_smsc_wdt_disable(); |
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} |
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return NOTIFY_DONE; |
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} |
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/* -- Module's structures ---------------------------------------*/ |
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|
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static const struct file_operations wb_smsc_wdt_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.write = wb_smsc_wdt_write, |
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.unlocked_ioctl = wb_smsc_wdt_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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.open = wb_smsc_wdt_open, |
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.release = wb_smsc_wdt_release, |
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}; |
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static struct notifier_block wb_smsc_wdt_notifier = { |
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.notifier_call = wb_smsc_wdt_notify_sys, |
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}; |
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static struct miscdevice wb_smsc_wdt_miscdev = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &wb_smsc_wdt_fops, |
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}; |
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/* -- Module init functions -------------------------------------*/ |
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/* module's "constructor" */ |
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static int __init wb_smsc_wdt_init(void) |
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{ |
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int ret; |
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pr_info("SMsC 37B787 watchdog component driver " |
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VERSION " initialising...\n"); |
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if (!request_region(IOPORT, IOPORT_SIZE, "SMsC 37B787 watchdog")) { |
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pr_err("Unable to register IO port %#x\n", IOPORT); |
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ret = -EBUSY; |
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goto out_pnp; |
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} |
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/* set new maximum, if it's too big */ |
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if (timeout > MAX_TIMEOUT) |
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timeout = MAX_TIMEOUT; |
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/* init the watchdog timer */ |
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wb_smsc_wdt_initialize(); |
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ret = register_reboot_notifier(&wb_smsc_wdt_notifier); |
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if (ret) { |
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pr_err("Unable to register reboot notifier err = %d\n", ret); |
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goto out_io; |
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} |
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ret = misc_register(&wb_smsc_wdt_miscdev); |
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if (ret) { |
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pr_err("Unable to register miscdev on minor %d\n", |
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WATCHDOG_MINOR); |
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goto out_rbt; |
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} |
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/* output info */ |
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pr_info("Timeout set to %d %s\n", |
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timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)"); |
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pr_info("Watchdog initialized and sleeping (nowayout=%d)...\n", |
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nowayout); |
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out_clean: |
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return ret; |
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out_rbt: |
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unregister_reboot_notifier(&wb_smsc_wdt_notifier); |
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out_io: |
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release_region(IOPORT, IOPORT_SIZE); |
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out_pnp: |
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goto out_clean; |
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} |
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/* module's "destructor" */ |
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static void __exit wb_smsc_wdt_exit(void) |
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{ |
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/* Stop the timer before we leave */ |
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if (!nowayout) { |
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wb_smsc_wdt_shutdown(); |
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pr_info("Watchdog disabled\n"); |
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} |
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misc_deregister(&wb_smsc_wdt_miscdev); |
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unregister_reboot_notifier(&wb_smsc_wdt_notifier); |
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release_region(IOPORT, IOPORT_SIZE); |
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|
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pr_info("SMsC 37B787 watchdog component driver removed\n"); |
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} |
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module_init(wb_smsc_wdt_init); |
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module_exit(wb_smsc_wdt_exit); |
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|
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MODULE_AUTHOR("Sven Anders <[email protected]>"); |
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MODULE_DESCRIPTION("Driver for SMsC 37B787 watchdog component (Version " |
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VERSION ")"); |
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MODULE_LICENSE("GPL"); |
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#ifdef SMSC_SUPPORT_MINUTES |
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module_param(unit, int, 0); |
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MODULE_PARM_DESC(unit, |
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"set unit to use, 0=seconds or 1=minutes, default is 0"); |
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#endif |
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module_param(timeout, int, 0); |
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MODULE_PARM_DESC(timeout, "range is 1-255 units, default is 60"); |
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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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