/* * MachZ ZF-Logic Watchdog Timer driver for Linux * * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * The author does NOT admit liability nor provide warranty for * any of this software. This material is provided "AS-IS" in * the hope that it may be useful for others. * * Author: Fernando Fuganti <fuganti@conectiva.com.br> * * Based on sbc60xxwdt.c by Jakob Oestergaard * * * We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the * following periods: * wd#1 - 2 seconds; * wd#2 - 7.2 ms; * After the expiration of wd#1, it can generate a NMI, SCI, SMI, or * a system RESET and it starts wd#2 that unconditionally will RESET * the system when the counter reaches zero. * * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <linux/timer.h> #include <linux/jiffies.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/fs.h> #include <linux/ioport.h> #include <linux/notifier.h> #include <linux/reboot.h> #include <linux/init.h> #include <linux/io.h> #include <linux/uaccess.h> #include <asm/system.h> /* ports */ #define ZF_IOBASE 0x218 #define INDEX 0x218 #define DATA_B 0x219 #define DATA_W 0x21A #define DATA_D 0x21A /* indexes */ /* size */ #define ZFL_VERSION 0x02 /* 16 */ #define CONTROL 0x10 /* 16 */ #define STATUS 0x12 /* 8 */ #define COUNTER_1 0x0C /* 16 */ #define COUNTER_2 0x0E /* 8 */ #define PULSE_LEN 0x0F /* 8 */ /* controls */ #define ENABLE_WD1 0x0001 #define ENABLE_WD2 0x0002 #define RESET_WD1 0x0010 #define RESET_WD2 0x0020 #define GEN_SCI 0x0100 #define GEN_NMI 0x0200 #define GEN_SMI 0x0400 #define GEN_RESET 0x0800 /* utilities */ #define WD1 0 #define WD2 1 #define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); } #define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); } #define zf_get_ZFL_version() zf_readw(ZFL_VERSION) static unsigned short zf_readw(unsigned char port) { outb(port, INDEX); return inw(DATA_W); } MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>"); MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); #define PFX "machzwd" static const struct watchdog_info zf_info = { .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = "ZF-Logic watchdog", }; /* * action refers to action taken when watchdog resets * 0 = GEN_RESET * 1 = GEN_SMI * 2 = GEN_NMI * 3 = GEN_SCI * defaults to GEN_RESET (0) */ static int action; module_param(action, int, 0); MODULE_PARM_DESC(action, "after watchdog resets, generate: " "0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI"); static void zf_ping(unsigned long data); static int zf_action = GEN_RESET; static unsigned long zf_is_open; static char zf_expect_close; static DEFINE_SPINLOCK(zf_port_lock); static DEFINE_TIMER(zf_timer, zf_ping, 0, 0); static unsigned long next_heartbeat; /* timeout for user land heart beat (10 seconds) */ #define ZF_USER_TIMEO (HZ*10) /* timeout for hardware watchdog (~500ms) */ #define ZF_HW_TIMEO (HZ/2) /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */ #define ZF_CTIMEOUT 0xffff #ifndef ZF_DEBUG #define dprintk(format, args...) #else #define dprintk(format, args...) \ pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args) #endif static inline void zf_set_status(unsigned char new) { zf_writeb(STATUS, new); } /* CONTROL register functions */ static inline unsigned short zf_get_control(void) { return zf_readw(CONTROL); } static inline void zf_set_control(unsigned short new) { zf_writew(CONTROL, new); } /* WD#? counter functions */ /* * Just set counter value */ static inline void zf_set_timer(unsigned short new, unsigned char n) { switch (n) { case WD1: zf_writew(COUNTER_1, new); case WD2: zf_writeb(COUNTER_2, new > 0xff ? 0xff : new); default: return; } } /* * stop hardware timer */ static void zf_timer_off(void) { unsigned int ctrl_reg = 0; unsigned long flags; /* stop internal ping */ del_timer_sync(&zf_timer); spin_lock_irqsave(&zf_port_lock, flags); /* stop watchdog timer */ ctrl_reg = zf_get_control(); ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */ ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2); zf_set_control(ctrl_reg); spin_unlock_irqrestore(&zf_port_lock, flags); pr_info("Watchdog timer is now disabled\n"); } /* * start hardware timer */ static void zf_timer_on(void) { unsigned int ctrl_reg = 0; unsigned long flags; spin_lock_irqsave(&zf_port_lock, flags); zf_writeb(PULSE_LEN, 0xff); zf_set_timer(ZF_CTIMEOUT, WD1); /* user land ping */ next_heartbeat = jiffies + ZF_USER_TIMEO; /* start the timer for internal ping */ mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO); /* start watchdog timer */ ctrl_reg = zf_get_control(); ctrl_reg |= (ENABLE_WD1|zf_action); zf_set_control(ctrl_reg); spin_unlock_irqrestore(&zf_port_lock, flags); pr_info("Watchdog timer is now enabled\n"); } static void zf_ping(unsigned long data) { unsigned int ctrl_reg = 0; unsigned long flags; zf_writeb(COUNTER_2, 0xff); if (time_before(jiffies, next_heartbeat)) { dprintk("time_before: %ld\n", next_heartbeat - jiffies); /* * reset event is activated by transition from 0 to 1 on * RESET_WD1 bit and we assume that it is already zero... */ spin_lock_irqsave(&zf_port_lock, flags); ctrl_reg = zf_get_control(); ctrl_reg |= RESET_WD1; zf_set_control(ctrl_reg); /* ...and nothing changes until here */ ctrl_reg &= ~(RESET_WD1); zf_set_control(ctrl_reg); spin_unlock_irqrestore(&zf_port_lock, flags); mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO); } else pr_crit("I will reset your machine\n"); } static ssize_t zf_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { /* See if we got the magic character */ if (count) { /* * no need to check for close confirmation * no way to disable watchdog ;) */ if (!nowayout) { size_t ofs; /* * note: just in case someone wrote the magic character * five months ago... */ zf_expect_close = 0; /* now scan */ for (ofs = 0; ofs != count; ofs++) { char c; if (get_user(c, buf + ofs)) return -EFAULT; if (c == 'V') { zf_expect_close = 42; dprintk("zf_expect_close = 42\n"); } } } /* * Well, anyhow someone wrote to us, * we should return that favour */ next_heartbeat = jiffies + ZF_USER_TIMEO; dprintk("user ping at %ld\n", jiffies); } return count; } static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { void __user *argp = (void __user *)arg; int __user *p = argp; switch (cmd) { case WDIOC_GETSUPPORT: if (copy_to_user(argp, &zf_info, sizeof(zf_info))) return -EFAULT; break; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_KEEPALIVE: zf_ping(0); break; default: return -ENOTTY; } return 0; } static int zf_open(struct inode *inode, struct file *file) { if (test_and_set_bit(0, &zf_is_open)) return -EBUSY; if (nowayout) __module_get(THIS_MODULE); zf_timer_on(); return nonseekable_open(inode, file); } static int zf_close(struct inode *inode, struct file *file) { if (zf_expect_close == 42) zf_timer_off(); else { del_timer(&zf_timer); pr_err("device file closed unexpectedly. Will not stop the WDT!\n"); } clear_bit(0, &zf_is_open); zf_expect_close = 0; return 0; } /* * Notifier for system down */ static int zf_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) zf_timer_off(); return NOTIFY_DONE; } static const struct file_operations zf_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = zf_write, .unlocked_ioctl = zf_ioctl, .open = zf_open, .release = zf_close, }; static struct miscdevice zf_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &zf_fops, }; /* * The device needs to learn about soft shutdowns in order to * turn the timebomb registers off. */ static struct notifier_block zf_notifier = { .notifier_call = zf_notify_sys, }; static void __init zf_show_action(int act) { static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" }; pr_info("Watchdog using action = %s\n", str[act]); } static int __init zf_init(void) { int ret; pr_info("MachZ ZF-Logic Watchdog driver initializing\n"); ret = zf_get_ZFL_version(); if (!ret || ret == 0xffff) { pr_warn("no ZF-Logic found\n"); return -ENODEV; } if (action <= 3 && action >= 0) zf_action = zf_action >> action; else action = 0; zf_show_action(action); if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) { pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE); ret = -EBUSY; goto no_region; } ret = register_reboot_notifier(&zf_notifier); if (ret) { pr_err("can't register reboot notifier (err=%d)\n", ret); goto no_reboot; } ret = misc_register(&zf_miscdev); if (ret) { pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR); goto no_misc; } zf_set_status(0); zf_set_control(0); return 0; no_misc: unregister_reboot_notifier(&zf_notifier); no_reboot: release_region(ZF_IOBASE, 3); no_region: return ret; } static void __exit zf_exit(void) { zf_timer_off(); misc_deregister(&zf_miscdev); unregister_reboot_notifier(&zf_notifier); release_region(ZF_IOBASE, 3); } module_init(zf_init); module_exit(zf_exit);