// SPDX-License-Identifier: GPL-2.0+ /* * Eurotech CPU-1220/1410/1420 on board WDT driver * * (c) Copyright 2001 Ascensit * (c) Copyright 2001 Rodolfo Giometti * (c) Copyright 2002 Rob Radez * * Based on wdt.c. * Original copyright messages: * * (c) Copyright 1996-1997 Alan Cox , * All Rights Reserved. * * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide * warranty for any of this software. This material is provided * "AS-IS" and at no charge. * * (c) Copyright 1995 Alan Cox * */ /* Changelog: * * 2001 - Rodolfo Giometti * Initial release * * 2002/04/25 - Rob Radez * clean up #includes * clean up locking * make __setup param unique * proper options in watchdog_info * add WDIOC_GETSTATUS and WDIOC_SETOPTIONS ioctls * add expect_close support * * 2002.05.30 - Joel Becker * Added Matt Domsch's nowayout module option. */ /* * The eurotech CPU-1220/1410/1420's watchdog is a part * of the on-board SUPER I/O device SMSC FDC 37B782. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include static unsigned long eurwdt_is_open; static int eurwdt_timeout; static char eur_expect_close; static DEFINE_SPINLOCK(eurwdt_lock); /* * You must set these - there is no sane way to probe for this board. */ static int io = 0x3f0; static int irq = 10; static char *ev = "int"; #define WDT_TIMEOUT 60 /* 1 minute */ 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) ")"); /* * Some symbolic names */ #define WDT_CTRL_REG 0x30 #define WDT_OUTPIN_CFG 0xe2 #define WDT_EVENT_INT 0x00 #define WDT_EVENT_REBOOT 0x08 #define WDT_UNIT_SEL 0xf1 #define WDT_UNIT_SECS 0x80 #define WDT_TIMEOUT_VAL 0xf2 #define WDT_TIMER_CFG 0xf3 module_param_hw(io, int, ioport, 0); MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)"); module_param_hw(irq, int, irq, 0); MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)"); module_param(ev, charp, 0); MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')"); /* * Programming support */ static inline void eurwdt_write_reg(u8 index, u8 data) { outb(index, io); outb(data, io+1); } static inline void eurwdt_lock_chip(void) { outb(0xaa, io); } static inline void eurwdt_unlock_chip(void) { outb(0x55, io); eurwdt_write_reg(0x07, 0x08); /* set the logical device */ } static inline void eurwdt_set_timeout(int timeout) { eurwdt_write_reg(WDT_TIMEOUT_VAL, (u8) timeout); } static inline void eurwdt_disable_timer(void) { eurwdt_set_timeout(0); } static void eurwdt_activate_timer(void) { eurwdt_disable_timer(); eurwdt_write_reg(WDT_CTRL_REG, 0x01); /* activate the WDT */ eurwdt_write_reg(WDT_OUTPIN_CFG, !strcmp("int", ev) ? WDT_EVENT_INT : WDT_EVENT_REBOOT); /* Setting interrupt line */ if (irq == 2 || irq > 15 || irq < 0) { pr_err("invalid irq number\n"); irq = 0; /* if invalid we disable interrupt */ } if (irq == 0) pr_info("interrupt disabled\n"); eurwdt_write_reg(WDT_TIMER_CFG, irq << 4); eurwdt_write_reg(WDT_UNIT_SEL, WDT_UNIT_SECS); /* we use seconds */ eurwdt_set_timeout(0); /* the default timeout */ } /* * Kernel methods. */ static irqreturn_t eurwdt_interrupt(int irq, void *dev_id) { pr_crit("timeout WDT timeout\n"); #ifdef ONLY_TESTING pr_crit("Would Reboot\n"); #else pr_crit("Initiating system reboot\n"); emergency_restart(); #endif return IRQ_HANDLED; } /** * eurwdt_ping: * * Reload counter one with the watchdog timeout. */ static void eurwdt_ping(void) { /* Write the watchdog default value */ eurwdt_set_timeout(eurwdt_timeout); } /** * eurwdt_write: * @file: file handle to the watchdog * @buf: buffer to write (unused as data does not matter here * @count: count of bytes * @ppos: pointer to the position to write. No seeks allowed * * A write to a watchdog device is defined as a keepalive signal. Any * write of data will do, as we don't define content meaning. */ static ssize_t eurwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { if (count) { if (!nowayout) { size_t i; eur_expect_close = 0; for (i = 0; i != count; i++) { char c; if (get_user(c, buf + i)) return -EFAULT; if (c == 'V') eur_expect_close = 42; } } spin_lock(&eurwdt_lock); eurwdt_ping(); /* the default timeout */ spin_unlock(&eurwdt_lock); } return count; } /** * eurwdt_ioctl: * @file: file handle to the device * @cmd: watchdog command * @arg: argument pointer * * The watchdog API defines a common set of functions for all watchdogs * according to their available features. */ static long eurwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { void __user *argp = (void __user *)arg; int __user *p = argp; static const struct watchdog_info ident = { .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = "WDT Eurotech CPU-1220/1410", }; int time; int options, retval = -EINVAL; switch (cmd) { case WDIOC_GETSUPPORT: return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_SETOPTIONS: if (get_user(options, p)) return -EFAULT; spin_lock(&eurwdt_lock); if (options & WDIOS_DISABLECARD) { eurwdt_disable_timer(); retval = 0; } if (options & WDIOS_ENABLECARD) { eurwdt_activate_timer(); eurwdt_ping(); retval = 0; } spin_unlock(&eurwdt_lock); return retval; case WDIOC_KEEPALIVE: spin_lock(&eurwdt_lock); eurwdt_ping(); spin_unlock(&eurwdt_lock); return 0; case WDIOC_SETTIMEOUT: if (copy_from_user(&time, p, sizeof(int))) return -EFAULT; /* Sanity check */ if (time < 0 || time > 255) return -EINVAL; spin_lock(&eurwdt_lock); eurwdt_timeout = time; eurwdt_set_timeout(time); spin_unlock(&eurwdt_lock); fallthrough; case WDIOC_GETTIMEOUT: return put_user(eurwdt_timeout, p); default: return -ENOTTY; } } /** * eurwdt_open: * @inode: inode of device * @file: file handle to device * * The misc device has been opened. The watchdog device is single * open and on opening we load the counter. */ static int eurwdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(0, &eurwdt_is_open)) return -EBUSY; eurwdt_timeout = WDT_TIMEOUT; /* initial timeout */ /* Activate the WDT */ eurwdt_activate_timer(); return stream_open(inode, file); } /** * eurwdt_release: * @inode: inode to board * @file: file handle to board * * The watchdog has a configurable API. There is a religious dispute * between people who want their watchdog to be able to shut down and * those who want to be sure if the watchdog manager dies the machine * reboots. In the former case we disable the counters, in the latter * case you have to open it again very soon. */ static int eurwdt_release(struct inode *inode, struct file *file) { if (eur_expect_close == 42) eurwdt_disable_timer(); else { pr_crit("Unexpected close, not stopping watchdog!\n"); eurwdt_ping(); } clear_bit(0, &eurwdt_is_open); eur_expect_close = 0; return 0; } /** * eurwdt_notify_sys: * @this: our notifier block * @code: the event being reported * @unused: unused * * Our notifier is called on system shutdowns. We want to turn the card * off at reboot otherwise the machine will reboot again during memory * test or worse yet during the following fsck. This would suck, in fact * trust me - if it happens it does suck. */ static int eurwdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { if (code == SYS_DOWN || code == SYS_HALT) eurwdt_disable_timer(); /* Turn the card off */ return NOTIFY_DONE; } /* * Kernel Interfaces */ static const struct file_operations eurwdt_fops = { .owner = THIS_MODULE, .write = eurwdt_write, .unlocked_ioctl = eurwdt_ioctl, .compat_ioctl = compat_ptr_ioctl, .open = eurwdt_open, .release = eurwdt_release, }; static struct miscdevice eurwdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &eurwdt_fops, }; /* * The WDT card needs to learn about soft shutdowns in order to * turn the timebomb registers off. */ static struct notifier_block eurwdt_notifier = { .notifier_call = eurwdt_notify_sys, }; /** * eurwdt_exit: * * Unload the watchdog. You cannot do this with any file handles open. * If your watchdog is set to continue ticking on close and you unload * it, well it keeps ticking. We won't get the interrupt but the board * will not touch PC memory so all is fine. You just have to load a new * module in 60 seconds or reboot. */ static void __exit eurwdt_exit(void) { eurwdt_lock_chip(); misc_deregister(&eurwdt_miscdev); unregister_reboot_notifier(&eurwdt_notifier); release_region(io, 2); free_irq(irq, NULL); } /** * eurwdt_init: * * Set up the WDT watchdog board. After grabbing the resources * we require we need also to unlock the device. * The open() function will actually kick the board off. */ static int __init eurwdt_init(void) { int ret; ret = request_irq(irq, eurwdt_interrupt, 0, "eurwdt", NULL); if (ret) { pr_err("IRQ %d is not free\n", irq); goto out; } if (!request_region(io, 2, "eurwdt")) { pr_err("IO %X is not free\n", io); ret = -EBUSY; goto outirq; } ret = register_reboot_notifier(&eurwdt_notifier); if (ret) { pr_err("can't register reboot notifier (err=%d)\n", ret); goto outreg; } ret = misc_register(&eurwdt_miscdev); if (ret) { pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR); goto outreboot; } eurwdt_unlock_chip(); ret = 0; pr_info("Eurotech WDT driver 0.01 at %X (Interrupt %d) - timeout event: %s\n", io, irq, (!strcmp("int", ev) ? "int" : "reboot")); out: return ret; outreboot: unregister_reboot_notifier(&eurwdt_notifier); outreg: release_region(io, 2); outirq: free_irq(irq, NULL); goto out; } module_init(eurwdt_init); module_exit(eurwdt_exit); MODULE_AUTHOR("Rodolfo Giometti"); MODULE_DESCRIPTION("Driver for Eurotech CPU-1220/1410 on board watchdog"); MODULE_LICENSE("GPL");