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bd490f8222
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20200707171121.GA13472@embeddedor Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
452 lines
9.8 KiB
C
452 lines
9.8 KiB
C
// 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 <jorge@dti2.net>
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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 DEBUG
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#define NAME "it8712f_wdt"
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MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
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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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