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450 lines
9.8 KiB
450 lines
9.8 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* IT8712F "Smart Guardian" Watchdog support |
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* |
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* Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <[email protected]> |
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* |
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* Based on info and code taken from: |
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* |
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* drivers/char/watchdog/scx200_wdt.c |
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* drivers/hwmon/it87.c |
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* IT8712F EC-LPC I/O Preliminary Specification 0.8.2 |
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* IT8712F EC-LPC I/O Preliminary Specification 0.9.3 |
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* |
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* The author(s) of this software shall not be held liable for damages |
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* of any nature resulting due to the use of this software. This |
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* software is provided AS-IS with no warranties. |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/init.h> |
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#include <linux/miscdevice.h> |
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#include <linux/watchdog.h> |
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#include <linux/notifier.h> |
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#include <linux/reboot.h> |
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#include <linux/fs.h> |
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#include <linux/spinlock.h> |
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#include <linux/uaccess.h> |
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#include <linux/io.h> |
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#include <linux/ioport.h> |
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#define NAME "it8712f_wdt" |
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MODULE_AUTHOR("Jorge Boncompte - DTI2 <[email protected]>"); |
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MODULE_DESCRIPTION("IT8712F Watchdog Driver"); |
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MODULE_LICENSE("GPL"); |
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static int max_units = 255; |
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static int margin = 60; /* in seconds */ |
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module_param(margin, int, 0); |
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MODULE_PARM_DESC(margin, "Watchdog margin in seconds"); |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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module_param(nowayout, bool, 0); |
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MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); |
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static unsigned long wdt_open; |
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static unsigned expect_close; |
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static unsigned char revision; |
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/* Dog Food address - We use the game port address */ |
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static unsigned short address; |
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#define REG 0x2e /* The register to read/write */ |
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#define VAL 0x2f /* The value to read/write */ |
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#define LDN 0x07 /* Register: Logical device select */ |
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#define DEVID 0x20 /* Register: Device ID */ |
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#define DEVREV 0x22 /* Register: Device Revision */ |
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#define ACT_REG 0x30 /* LDN Register: Activation */ |
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#define BASE_REG 0x60 /* LDN Register: Base address */ |
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#define IT8712F_DEVID 0x8712 |
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#define LDN_GPIO 0x07 /* GPIO and Watch Dog Timer */ |
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#define LDN_GAME 0x09 /* Game Port */ |
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#define WDT_CONTROL 0x71 /* WDT Register: Control */ |
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#define WDT_CONFIG 0x72 /* WDT Register: Configuration */ |
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#define WDT_TIMEOUT 0x73 /* WDT Register: Timeout Value */ |
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#define WDT_RESET_GAME 0x10 /* Reset timer on read or write to game port */ |
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#define WDT_RESET_KBD 0x20 /* Reset timer on keyboard interrupt */ |
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#define WDT_RESET_MOUSE 0x40 /* Reset timer on mouse interrupt */ |
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#define WDT_RESET_CIR 0x80 /* Reset timer on consumer IR interrupt */ |
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#define WDT_UNIT_SEC 0x80 /* If 0 in MINUTES */ |
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#define WDT_OUT_PWROK 0x10 /* Pulse PWROK on timeout */ |
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#define WDT_OUT_KRST 0x40 /* Pulse reset on timeout */ |
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static int wdt_control_reg = WDT_RESET_GAME; |
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module_param(wdt_control_reg, int, 0); |
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MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control " |
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"register. The default WDT_RESET_GAME resets the timer on " |
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"game port reads that this driver generates. You can also " |
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"use KBD, MOUSE or CIR if you have some external way to " |
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"generate those interrupts."); |
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static int superio_inb(int reg) |
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{ |
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outb(reg, REG); |
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return inb(VAL); |
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} |
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static void superio_outb(int val, int reg) |
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{ |
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outb(reg, REG); |
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outb(val, VAL); |
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} |
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static int superio_inw(int reg) |
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{ |
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int val; |
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outb(reg++, REG); |
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val = inb(VAL) << 8; |
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outb(reg, REG); |
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val |= inb(VAL); |
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return val; |
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} |
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static inline void superio_select(int ldn) |
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{ |
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outb(LDN, REG); |
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outb(ldn, VAL); |
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} |
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static inline int superio_enter(void) |
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{ |
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/* |
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* Try to reserve REG and REG + 1 for exclusive access. |
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*/ |
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if (!request_muxed_region(REG, 2, NAME)) |
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return -EBUSY; |
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outb(0x87, REG); |
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outb(0x01, REG); |
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outb(0x55, REG); |
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outb(0x55, REG); |
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return 0; |
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} |
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static inline void superio_exit(void) |
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{ |
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outb(0x02, REG); |
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outb(0x02, VAL); |
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release_region(REG, 2); |
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} |
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static inline void it8712f_wdt_ping(void) |
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{ |
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if (wdt_control_reg & WDT_RESET_GAME) |
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inb(address); |
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} |
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static void it8712f_wdt_update_margin(void) |
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{ |
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int config = WDT_OUT_KRST | WDT_OUT_PWROK; |
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int units = margin; |
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/* Switch to minutes precision if the configured margin |
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* value does not fit within the register width. |
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*/ |
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if (units <= max_units) { |
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config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */ |
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pr_info("timer margin %d seconds\n", units); |
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} else { |
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units /= 60; |
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pr_info("timer margin %d minutes\n", units); |
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} |
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superio_outb(config, WDT_CONFIG); |
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if (revision >= 0x08) |
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superio_outb(units >> 8, WDT_TIMEOUT + 1); |
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superio_outb(units, WDT_TIMEOUT); |
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} |
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static int it8712f_wdt_get_status(void) |
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{ |
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if (superio_inb(WDT_CONTROL) & 0x01) |
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return WDIOF_CARDRESET; |
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else |
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return 0; |
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} |
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static int it8712f_wdt_enable(void) |
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{ |
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int ret = superio_enter(); |
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if (ret) |
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return ret; |
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pr_debug("enabling watchdog timer\n"); |
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superio_select(LDN_GPIO); |
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superio_outb(wdt_control_reg, WDT_CONTROL); |
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it8712f_wdt_update_margin(); |
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superio_exit(); |
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it8712f_wdt_ping(); |
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return 0; |
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} |
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static int it8712f_wdt_disable(void) |
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{ |
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int ret = superio_enter(); |
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if (ret) |
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return ret; |
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pr_debug("disabling watchdog timer\n"); |
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superio_select(LDN_GPIO); |
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superio_outb(0, WDT_CONFIG); |
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superio_outb(0, WDT_CONTROL); |
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if (revision >= 0x08) |
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superio_outb(0, WDT_TIMEOUT + 1); |
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superio_outb(0, WDT_TIMEOUT); |
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superio_exit(); |
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return 0; |
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} |
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static int it8712f_wdt_notify(struct notifier_block *this, |
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unsigned long code, void *unused) |
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{ |
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if (code == SYS_HALT || code == SYS_POWER_OFF) |
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if (!nowayout) |
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it8712f_wdt_disable(); |
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return NOTIFY_DONE; |
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} |
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static struct notifier_block it8712f_wdt_notifier = { |
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.notifier_call = it8712f_wdt_notify, |
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}; |
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static ssize_t it8712f_wdt_write(struct file *file, const char __user *data, |
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size_t len, loff_t *ppos) |
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{ |
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/* check for a magic close character */ |
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if (len) { |
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size_t i; |
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it8712f_wdt_ping(); |
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expect_close = 0; |
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for (i = 0; i < len; ++i) { |
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char c; |
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if (get_user(c, data + i)) |
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return -EFAULT; |
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if (c == 'V') |
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expect_close = 42; |
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} |
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} |
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return len; |
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} |
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static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd, |
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unsigned long arg) |
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{ |
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void __user *argp = (void __user *)arg; |
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int __user *p = argp; |
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static const struct watchdog_info ident = { |
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.identity = "IT8712F Watchdog", |
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.firmware_version = 1, |
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
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WDIOF_MAGICCLOSE, |
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}; |
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int value; |
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int ret; |
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switch (cmd) { |
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case WDIOC_GETSUPPORT: |
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if (copy_to_user(argp, &ident, sizeof(ident))) |
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return -EFAULT; |
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return 0; |
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case WDIOC_GETSTATUS: |
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ret = superio_enter(); |
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if (ret) |
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return ret; |
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superio_select(LDN_GPIO); |
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value = it8712f_wdt_get_status(); |
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superio_exit(); |
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return put_user(value, p); |
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case WDIOC_GETBOOTSTATUS: |
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return put_user(0, p); |
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case WDIOC_KEEPALIVE: |
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it8712f_wdt_ping(); |
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return 0; |
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case WDIOC_SETTIMEOUT: |
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if (get_user(value, p)) |
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return -EFAULT; |
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if (value < 1) |
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return -EINVAL; |
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if (value > (max_units * 60)) |
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return -EINVAL; |
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margin = value; |
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ret = superio_enter(); |
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if (ret) |
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return ret; |
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superio_select(LDN_GPIO); |
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it8712f_wdt_update_margin(); |
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superio_exit(); |
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it8712f_wdt_ping(); |
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fallthrough; |
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case WDIOC_GETTIMEOUT: |
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if (put_user(margin, p)) |
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return -EFAULT; |
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return 0; |
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default: |
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return -ENOTTY; |
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} |
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} |
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static int it8712f_wdt_open(struct inode *inode, struct file *file) |
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{ |
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int ret; |
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/* only allow one at a time */ |
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if (test_and_set_bit(0, &wdt_open)) |
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return -EBUSY; |
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ret = it8712f_wdt_enable(); |
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if (ret) |
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return ret; |
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return stream_open(inode, file); |
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} |
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static int it8712f_wdt_release(struct inode *inode, struct file *file) |
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{ |
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if (expect_close != 42) { |
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pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n"); |
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} else if (!nowayout) { |
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if (it8712f_wdt_disable()) |
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pr_warn("Watchdog disable failed\n"); |
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} |
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expect_close = 0; |
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clear_bit(0, &wdt_open); |
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return 0; |
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} |
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static const struct file_operations it8712f_wdt_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.write = it8712f_wdt_write, |
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.unlocked_ioctl = it8712f_wdt_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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.open = it8712f_wdt_open, |
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.release = it8712f_wdt_release, |
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}; |
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static struct miscdevice it8712f_wdt_miscdev = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &it8712f_wdt_fops, |
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}; |
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static int __init it8712f_wdt_find(unsigned short *address) |
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{ |
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int err = -ENODEV; |
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int chip_type; |
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int ret = superio_enter(); |
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if (ret) |
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return ret; |
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chip_type = superio_inw(DEVID); |
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if (chip_type != IT8712F_DEVID) |
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goto exit; |
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superio_select(LDN_GAME); |
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superio_outb(1, ACT_REG); |
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if (!(superio_inb(ACT_REG) & 0x01)) { |
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pr_err("Device not activated, skipping\n"); |
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goto exit; |
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} |
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*address = superio_inw(BASE_REG); |
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if (*address == 0) { |
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pr_err("Base address not set, skipping\n"); |
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goto exit; |
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} |
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err = 0; |
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revision = superio_inb(DEVREV) & 0x0f; |
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/* Later revisions have 16-bit values per datasheet 0.9.1 */ |
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if (revision >= 0x08) |
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max_units = 65535; |
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if (margin > (max_units * 60)) |
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margin = (max_units * 60); |
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pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n", |
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chip_type, revision, *address); |
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exit: |
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superio_exit(); |
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return err; |
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} |
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static int __init it8712f_wdt_init(void) |
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{ |
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int err = 0; |
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if (it8712f_wdt_find(&address)) |
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return -ENODEV; |
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if (!request_region(address, 1, "IT8712F Watchdog")) { |
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pr_warn("watchdog I/O region busy\n"); |
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return -EBUSY; |
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} |
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err = it8712f_wdt_disable(); |
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if (err) { |
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pr_err("unable to disable watchdog timer\n"); |
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goto out; |
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} |
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err = register_reboot_notifier(&it8712f_wdt_notifier); |
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if (err) { |
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pr_err("unable to register reboot notifier\n"); |
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goto out; |
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} |
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err = misc_register(&it8712f_wdt_miscdev); |
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if (err) { |
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pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
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WATCHDOG_MINOR, err); |
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goto reboot_out; |
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} |
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return 0; |
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reboot_out: |
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unregister_reboot_notifier(&it8712f_wdt_notifier); |
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out: |
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release_region(address, 1); |
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return err; |
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} |
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static void __exit it8712f_wdt_exit(void) |
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{ |
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misc_deregister(&it8712f_wdt_miscdev); |
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unregister_reboot_notifier(&it8712f_wdt_notifier); |
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release_region(address, 1); |
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} |
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module_init(it8712f_wdt_init); |
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module_exit(it8712f_wdt_exit);
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