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452 lines
9.7 KiB
452 lines
9.7 KiB
// 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 <[email protected]> |
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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 <[email protected]> |
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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 <[email protected]>"); |
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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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