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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>
453 lines
9.7 KiB
C
453 lines
9.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* MachZ ZF-Logic Watchdog Timer driver for Linux
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*
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* The author does 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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* Author: Fernando Fuganti <fuganti@conectiva.com.br>
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*
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* Based on sbc60xxwdt.c by Jakob Oestergaard
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*
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* We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the
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* following periods:
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* wd#1 - 2 seconds;
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* wd#2 - 7.2 ms;
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* After the expiration of wd#1, it can generate a NMI, SCI, SMI, or
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* a system RESET and it starts wd#2 that unconditionally will RESET
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* the system when the counter reaches zero.
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*
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* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
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* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
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*/
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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/types.h>
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#include <linux/timer.h>
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#include <linux/jiffies.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.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/io.h>
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#include <linux/uaccess.h>
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/* ports */
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#define ZF_IOBASE 0x218
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#define INDEX 0x218
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#define DATA_B 0x219
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#define DATA_W 0x21A
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#define DATA_D 0x21A
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/* indexes */ /* size */
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#define ZFL_VERSION 0x02 /* 16 */
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#define CONTROL 0x10 /* 16 */
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#define STATUS 0x12 /* 8 */
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#define COUNTER_1 0x0C /* 16 */
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#define COUNTER_2 0x0E /* 8 */
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#define PULSE_LEN 0x0F /* 8 */
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/* controls */
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#define ENABLE_WD1 0x0001
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#define ENABLE_WD2 0x0002
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#define RESET_WD1 0x0010
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#define RESET_WD2 0x0020
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#define GEN_SCI 0x0100
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#define GEN_NMI 0x0200
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#define GEN_SMI 0x0400
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#define GEN_RESET 0x0800
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/* utilities */
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#define WD1 0
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#define WD2 1
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#define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); }
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#define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); }
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#define zf_get_ZFL_version() zf_readw(ZFL_VERSION)
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static unsigned short zf_readw(unsigned char port)
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{
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outb(port, INDEX);
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return inw(DATA_W);
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}
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MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
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MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
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MODULE_LICENSE("GPL");
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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,
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"Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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#define PFX "machzwd"
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static const struct watchdog_info zf_info = {
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.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
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.firmware_version = 1,
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.identity = "ZF-Logic watchdog",
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};
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/*
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* action refers to action taken when watchdog resets
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* 0 = GEN_RESET
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* 1 = GEN_SMI
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* 2 = GEN_NMI
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* 3 = GEN_SCI
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* defaults to GEN_RESET (0)
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*/
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static int action;
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module_param(action, int, 0);
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MODULE_PARM_DESC(action, "after watchdog resets, generate: "
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"0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
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static void zf_ping(struct timer_list *unused);
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static int zf_action = GEN_RESET;
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static unsigned long zf_is_open;
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static char zf_expect_close;
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static DEFINE_SPINLOCK(zf_port_lock);
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static DEFINE_TIMER(zf_timer, zf_ping);
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static unsigned long next_heartbeat;
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/* timeout for user land heart beat (10 seconds) */
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#define ZF_USER_TIMEO (HZ*10)
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/* timeout for hardware watchdog (~500ms) */
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#define ZF_HW_TIMEO (HZ/2)
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/* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
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#define ZF_CTIMEOUT 0xffff
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#ifndef ZF_DEBUG
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#define dprintk(format, args...)
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#else
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#define dprintk(format, args...) \
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pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args)
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#endif
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static inline void zf_set_status(unsigned char new)
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{
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zf_writeb(STATUS, new);
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}
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/* CONTROL register functions */
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static inline unsigned short zf_get_control(void)
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{
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return zf_readw(CONTROL);
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}
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static inline void zf_set_control(unsigned short new)
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{
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zf_writew(CONTROL, new);
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}
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/* WD#? counter functions */
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/*
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* Just set counter value
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*/
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static inline void zf_set_timer(unsigned short new, unsigned char n)
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{
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switch (n) {
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case WD1:
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zf_writew(COUNTER_1, new);
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fallthrough;
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case WD2:
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zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
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default:
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return;
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}
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}
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/*
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* stop hardware timer
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*/
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static void zf_timer_off(void)
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{
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unsigned int ctrl_reg = 0;
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unsigned long flags;
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/* stop internal ping */
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del_timer_sync(&zf_timer);
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spin_lock_irqsave(&zf_port_lock, flags);
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/* stop watchdog timer */
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ctrl_reg = zf_get_control();
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ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */
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ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
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zf_set_control(ctrl_reg);
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spin_unlock_irqrestore(&zf_port_lock, flags);
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pr_info("Watchdog timer is now disabled\n");
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}
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/*
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* start hardware timer
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*/
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static void zf_timer_on(void)
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{
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unsigned int ctrl_reg = 0;
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unsigned long flags;
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spin_lock_irqsave(&zf_port_lock, flags);
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zf_writeb(PULSE_LEN, 0xff);
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zf_set_timer(ZF_CTIMEOUT, WD1);
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/* user land ping */
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next_heartbeat = jiffies + ZF_USER_TIMEO;
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/* start the timer for internal ping */
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mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
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/* start watchdog timer */
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ctrl_reg = zf_get_control();
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ctrl_reg |= (ENABLE_WD1|zf_action);
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zf_set_control(ctrl_reg);
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spin_unlock_irqrestore(&zf_port_lock, flags);
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pr_info("Watchdog timer is now enabled\n");
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}
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static void zf_ping(struct timer_list *unused)
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{
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unsigned int ctrl_reg = 0;
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unsigned long flags;
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zf_writeb(COUNTER_2, 0xff);
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if (time_before(jiffies, next_heartbeat)) {
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dprintk("time_before: %ld\n", next_heartbeat - jiffies);
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/*
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* reset event is activated by transition from 0 to 1 on
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* RESET_WD1 bit and we assume that it is already zero...
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*/
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spin_lock_irqsave(&zf_port_lock, flags);
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ctrl_reg = zf_get_control();
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ctrl_reg |= RESET_WD1;
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zf_set_control(ctrl_reg);
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/* ...and nothing changes until here */
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ctrl_reg &= ~(RESET_WD1);
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zf_set_control(ctrl_reg);
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spin_unlock_irqrestore(&zf_port_lock, flags);
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mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
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} else
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pr_crit("I will reset your machine\n");
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}
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static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
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loff_t *ppos)
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{
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/* See if we got the magic character */
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if (count) {
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/*
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* no need to check for close confirmation
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* no way to disable watchdog ;)
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*/
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if (!nowayout) {
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size_t ofs;
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/*
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* note: just in case someone wrote the magic character
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* five months ago...
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*/
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zf_expect_close = 0;
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/* now scan */
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for (ofs = 0; ofs != count; ofs++) {
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char c;
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if (get_user(c, buf + ofs))
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return -EFAULT;
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if (c == 'V') {
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zf_expect_close = 42;
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dprintk("zf_expect_close = 42\n");
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}
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}
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}
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/*
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* Well, anyhow someone wrote to us,
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* we should return that favour
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*/
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next_heartbeat = jiffies + ZF_USER_TIMEO;
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dprintk("user ping at %ld\n", jiffies);
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}
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return count;
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}
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static long zf_ioctl(struct file *file, unsigned int cmd, 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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switch (cmd) {
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case WDIOC_GETSUPPORT:
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if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
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return -EFAULT;
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break;
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case WDIOC_GETSTATUS:
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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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zf_ping(NULL);
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break;
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default:
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return -ENOTTY;
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}
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return 0;
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}
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static int zf_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(0, &zf_is_open))
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return -EBUSY;
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if (nowayout)
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__module_get(THIS_MODULE);
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zf_timer_on();
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return stream_open(inode, file);
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}
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static int zf_close(struct inode *inode, struct file *file)
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{
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if (zf_expect_close == 42)
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zf_timer_off();
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else {
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del_timer(&zf_timer);
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pr_err("device file closed unexpectedly. Will not stop the WDT!\n");
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}
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clear_bit(0, &zf_is_open);
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zf_expect_close = 0;
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return 0;
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}
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/*
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* Notifier for system down
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*/
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static int zf_notify_sys(struct notifier_block *this, unsigned long code,
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void *unused)
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{
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if (code == SYS_DOWN || code == SYS_HALT)
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zf_timer_off();
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return NOTIFY_DONE;
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}
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static const struct file_operations zf_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = zf_write,
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.unlocked_ioctl = zf_ioctl,
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.compat_ioctl = compat_ptr_ioctl,
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.open = zf_open,
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.release = zf_close,
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};
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static struct miscdevice zf_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &zf_fops,
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};
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/*
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* The device needs to learn about soft shutdowns in order to
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* turn the timebomb registers off.
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*/
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static struct notifier_block zf_notifier = {
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.notifier_call = zf_notify_sys,
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};
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static void __init zf_show_action(int act)
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{
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static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" };
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pr_info("Watchdog using action = %s\n", str[act]);
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}
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static int __init zf_init(void)
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{
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int ret;
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pr_info("MachZ ZF-Logic Watchdog driver initializing\n");
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ret = zf_get_ZFL_version();
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if (!ret || ret == 0xffff) {
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pr_warn("no ZF-Logic found\n");
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return -ENODEV;
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}
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if (action <= 3 && action >= 0)
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zf_action = zf_action >> action;
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else
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action = 0;
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zf_show_action(action);
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if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
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pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE);
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ret = -EBUSY;
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goto no_region;
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}
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ret = register_reboot_notifier(&zf_notifier);
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if (ret) {
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pr_err("can't register reboot notifier (err=%d)\n", ret);
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goto no_reboot;
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}
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ret = misc_register(&zf_miscdev);
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if (ret) {
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pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
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goto no_misc;
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}
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zf_set_status(0);
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zf_set_control(0);
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return 0;
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no_misc:
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unregister_reboot_notifier(&zf_notifier);
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no_reboot:
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release_region(ZF_IOBASE, 3);
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no_region:
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return ret;
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}
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static void __exit zf_exit(void)
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{
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zf_timer_off();
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misc_deregister(&zf_miscdev);
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unregister_reboot_notifier(&zf_notifier);
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release_region(ZF_IOBASE, 3);
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}
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module_init(zf_init);
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module_exit(zf_exit);
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