diff options
Diffstat (limited to 'drivers/watchdog/wdt.c')
| -rw-r--r-- | drivers/watchdog/wdt.c | 664 |
1 files changed, 664 insertions, 0 deletions
diff --git a/drivers/watchdog/wdt.c b/drivers/watchdog/wdt.c new file mode 100644 index 000000000..183876156 --- /dev/null +++ b/drivers/watchdog/wdt.c @@ -0,0 +1,664 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Industrial Computer Source WDT501 driver + * + * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>, + * 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 <alan@lxorguk.ukuu.org.uk> + * + * Release 0.10. + * + * Fixes + * Dave Gregorich : Modularisation and minor bugs + * Alan Cox : Added the watchdog ioctl() stuff + * Alan Cox : Fixed the reboot problem (as noted by + * Matt Crocker). + * Alan Cox : Added wdt= boot option + * Alan Cox : Cleaned up copy/user stuff + * Tim Hockin : Added insmod parameters, comment + * cleanup, parameterized timeout + * Tigran Aivazian : Restructured wdt_init() to handle + * failures + * Joel Becker : Added WDIOC_GET/SETTIMEOUT + * Matt Domsch : Added nowayout module option + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.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 "wd501p.h" + +static unsigned long wdt_is_open; +static char expect_close; + +/* + * Module parameters + */ + +#define WD_TIMO 60 /* Default heartbeat = 60 seconds */ + +static int heartbeat = WD_TIMO; +static int wd_heartbeat; +module_param(heartbeat, int, 0); +MODULE_PARM_DESC(heartbeat, + "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default=" + __MODULE_STRING(WD_TIMO) ")"); + +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) ")"); + +/* You must set these - there is no sane way to probe for this board. */ +static int io = 0x240; +static int irq = 11; + +static DEFINE_SPINLOCK(wdt_lock); + +module_param_hw(io, int, ioport, 0); +MODULE_PARM_DESC(io, "WDT io port (default=0x240)"); +module_param_hw(irq, int, irq, 0); +MODULE_PARM_DESC(irq, "WDT irq (default=11)"); + +/* Support for the Fan Tachometer on the WDT501-P */ +static int tachometer; +module_param(tachometer, int, 0); +MODULE_PARM_DESC(tachometer, + "WDT501-P Fan Tachometer support (0=disable, default=0)"); + +static int type = 500; +module_param(type, int, 0); +MODULE_PARM_DESC(type, + "WDT501-P Card type (500 or 501, default=500)"); + +/* + * Programming support + */ + +static void wdt_ctr_mode(int ctr, int mode) +{ + ctr <<= 6; + ctr |= 0x30; + ctr |= (mode << 1); + outb_p(ctr, WDT_CR); +} + +static void wdt_ctr_load(int ctr, int val) +{ + outb_p(val&0xFF, WDT_COUNT0+ctr); + outb_p(val>>8, WDT_COUNT0+ctr); +} + +/** + * wdt_start: + * + * Start the watchdog driver. + */ + +static int wdt_start(void) +{ + unsigned long flags; + spin_lock_irqsave(&wdt_lock, flags); + inb_p(WDT_DC); /* Disable watchdog */ + wdt_ctr_mode(0, 3); /* Program CTR0 for Mode 3: + Square Wave Generator */ + wdt_ctr_mode(1, 2); /* Program CTR1 for Mode 2: + Rate Generator */ + wdt_ctr_mode(2, 0); /* Program CTR2 for Mode 0: + Pulse on Terminal Count */ + wdt_ctr_load(0, 8948); /* Count at 100Hz */ + wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */ + wdt_ctr_load(2, 65535); /* Length of reset pulse */ + outb_p(0, WDT_DC); /* Enable watchdog */ + spin_unlock_irqrestore(&wdt_lock, flags); + return 0; +} + +/** + * wdt_stop: + * + * Stop the watchdog driver. + */ + +static int wdt_stop(void) +{ + unsigned long flags; + spin_lock_irqsave(&wdt_lock, flags); + /* Turn the card off */ + inb_p(WDT_DC); /* Disable watchdog */ + wdt_ctr_load(2, 0); /* 0 length reset pulses now */ + spin_unlock_irqrestore(&wdt_lock, flags); + return 0; +} + +/** + * wdt_ping: + * + * Reload counter one with the watchdog heartbeat. We don't bother + * reloading the cascade counter. + */ + +static void wdt_ping(void) +{ + unsigned long flags; + spin_lock_irqsave(&wdt_lock, flags); + /* Write a watchdog value */ + inb_p(WDT_DC); /* Disable watchdog */ + wdt_ctr_mode(1, 2); /* Re-Program CTR1 for Mode 2: + Rate Generator */ + wdt_ctr_load(1, wd_heartbeat); /* Heartbeat */ + outb_p(0, WDT_DC); /* Enable watchdog */ + spin_unlock_irqrestore(&wdt_lock, flags); +} + +/** + * wdt_set_heartbeat: + * @t: the new heartbeat value that needs to be set. + * + * Set a new heartbeat value for the watchdog device. If the heartbeat + * value is incorrect we keep the old value and return -EINVAL. If + * successful we return 0. + */ + +static int wdt_set_heartbeat(int t) +{ + if (t < 1 || t > 65535) + return -EINVAL; + + heartbeat = t; + wd_heartbeat = t * 100; + return 0; +} + +/** + * wdt_get_status: + * + * Extract the status information from a WDT watchdog device. There are + * several board variants so we have to know which bits are valid. Some + * bits default to one and some to zero in order to be maximally painful. + * + * we then map the bits onto the status ioctl flags. + */ + +static int wdt_get_status(void) +{ + unsigned char new_status; + int status = 0; + unsigned long flags; + + spin_lock_irqsave(&wdt_lock, flags); + new_status = inb_p(WDT_SR); + spin_unlock_irqrestore(&wdt_lock, flags); + + if (new_status & WDC_SR_ISOI0) + status |= WDIOF_EXTERN1; + if (new_status & WDC_SR_ISII1) + status |= WDIOF_EXTERN2; + if (type == 501) { + if (!(new_status & WDC_SR_TGOOD)) + status |= WDIOF_OVERHEAT; + if (!(new_status & WDC_SR_PSUOVER)) + status |= WDIOF_POWEROVER; + if (!(new_status & WDC_SR_PSUUNDR)) + status |= WDIOF_POWERUNDER; + if (tachometer) { + if (!(new_status & WDC_SR_FANGOOD)) + status |= WDIOF_FANFAULT; + } + } + return status; +} + +/** + * wdt_get_temperature: + * + * Reports the temperature in degrees Fahrenheit. The API is in + * farenheit. It was designed by an imperial measurement luddite. + */ + +static int wdt_get_temperature(void) +{ + unsigned short c; + unsigned long flags; + + spin_lock_irqsave(&wdt_lock, flags); + c = inb_p(WDT_RT); + spin_unlock_irqrestore(&wdt_lock, flags); + return (c * 11 / 15) + 7; +} + +static void wdt_decode_501(int status) +{ + if (!(status & WDC_SR_TGOOD)) + pr_crit("Overheat alarm (%d)\n", inb_p(WDT_RT)); + if (!(status & WDC_SR_PSUOVER)) + pr_crit("PSU over voltage\n"); + if (!(status & WDC_SR_PSUUNDR)) + pr_crit("PSU under voltage\n"); +} + +/** + * wdt_interrupt: + * @irq: Interrupt number + * @dev_id: Unused as we don't allow multiple devices. + * + * Handle an interrupt from the board. These are raised when the status + * map changes in what the board considers an interesting way. That means + * a failure condition occurring. + */ + +static irqreturn_t wdt_interrupt(int irq, void *dev_id) +{ + /* + * Read the status register see what is up and + * then printk it. + */ + unsigned char status; + + spin_lock(&wdt_lock); + status = inb_p(WDT_SR); + + pr_crit("WDT status %d\n", status); + + if (type == 501) { + wdt_decode_501(status); + if (tachometer) { + if (!(status & WDC_SR_FANGOOD)) + pr_crit("Possible fan fault\n"); + } + } + if (!(status & WDC_SR_WCCR)) { +#ifdef SOFTWARE_REBOOT +#ifdef ONLY_TESTING + pr_crit("Would Reboot\n"); +#else + pr_crit("Initiating system reboot\n"); + emergency_restart(); +#endif +#else + pr_crit("Reset in 5ms\n"); +#endif + } + spin_unlock(&wdt_lock); + return IRQ_HANDLED; +} + + +/** + * wdt_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 we don't define content meaning. + */ + +static ssize_t wdt_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + if (count) { + if (!nowayout) { + size_t i; + + /* In case it was set long ago */ + expect_close = 0; + + for (i = 0; i != count; i++) { + char c; + if (get_user(c, buf + i)) + return -EFAULT; + if (c == 'V') + expect_close = 42; + } + } + wdt_ping(); + } + return count; +} + +/** + * wdt_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. We only actually usefully support + * querying capabilities and current status. + */ + +static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + void __user *argp = (void __user *)arg; + int __user *p = argp; + int new_heartbeat; + int status; + + struct watchdog_info ident = { + .options = WDIOF_SETTIMEOUT| + WDIOF_MAGICCLOSE| + WDIOF_KEEPALIVEPING, + .firmware_version = 1, + .identity = "WDT500/501", + }; + + /* Add options according to the card we have */ + ident.options |= (WDIOF_EXTERN1|WDIOF_EXTERN2); + if (type == 501) { + ident.options |= (WDIOF_OVERHEAT|WDIOF_POWERUNDER| + WDIOF_POWEROVER); + if (tachometer) + ident.options |= WDIOF_FANFAULT; + } + + switch (cmd) { + case WDIOC_GETSUPPORT: + return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; + case WDIOC_GETSTATUS: + status = wdt_get_status(); + return put_user(status, p); + case WDIOC_GETBOOTSTATUS: + return put_user(0, p); + case WDIOC_KEEPALIVE: + wdt_ping(); + return 0; + case WDIOC_SETTIMEOUT: + if (get_user(new_heartbeat, p)) + return -EFAULT; + if (wdt_set_heartbeat(new_heartbeat)) + return -EINVAL; + wdt_ping(); + fallthrough; + case WDIOC_GETTIMEOUT: + return put_user(heartbeat, p); + default: + return -ENOTTY; + } +} + +/** + * wdt_open: + * @inode: inode of device + * @file: file handle to device + * + * The watchdog device has been opened. The watchdog device is single + * open and on opening we load the counters. Counter zero is a 100Hz + * cascade, into counter 1 which downcounts to reboot. When the counter + * triggers counter 2 downcounts the length of the reset pulse which + * set set to be as long as possible. + */ + +static int wdt_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(0, &wdt_is_open)) + return -EBUSY; + /* + * Activate + */ + wdt_start(); + return stream_open(inode, file); +} + +/** + * wdt_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 wdt_release(struct inode *inode, struct file *file) +{ + if (expect_close == 42) { + wdt_stop(); + clear_bit(0, &wdt_is_open); + } else { + pr_crit("WDT device closed unexpectedly. WDT will not stop!\n"); + wdt_ping(); + } + expect_close = 0; + return 0; +} + +/** + * wdt_temp_read: + * @file: file handle to the watchdog board + * @buf: buffer to write 1 byte into + * @count: length of buffer + * @ptr: offset (no seek allowed) + * + * Temp_read reports the temperature in degrees Fahrenheit. The API is in + * farenheit. It was designed by an imperial measurement luddite. + */ + +static ssize_t wdt_temp_read(struct file *file, char __user *buf, + size_t count, loff_t *ptr) +{ + int temperature = wdt_get_temperature(); + + if (copy_to_user(buf, &temperature, 1)) + return -EFAULT; + + return 1; +} + +/** + * wdt_temp_open: + * @inode: inode of device + * @file: file handle to device + * + * The temperature device has been opened. + */ + +static int wdt_temp_open(struct inode *inode, struct file *file) +{ + return stream_open(inode, file); +} + +/** + * wdt_temp_release: + * @inode: inode to board + * @file: file handle to board + * + * The temperature device has been closed. + */ + +static int wdt_temp_release(struct inode *inode, struct file *file) +{ + return 0; +} + +/** + * wdt_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 wdt_notify_sys(struct notifier_block *this, unsigned long code, + void *unused) +{ + if (code == SYS_DOWN || code == SYS_HALT) + wdt_stop(); + return NOTIFY_DONE; +} + +/* + * Kernel Interfaces + */ + + +static const struct file_operations wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = wdt_write, + .unlocked_ioctl = wdt_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .open = wdt_open, + .release = wdt_release, +}; + +static struct miscdevice wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &wdt_fops, +}; + +static const struct file_operations wdt_temp_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .read = wdt_temp_read, + .open = wdt_temp_open, + .release = wdt_temp_release, +}; + +static struct miscdevice temp_miscdev = { + .minor = TEMP_MINOR, + .name = "temperature", + .fops = &wdt_temp_fops, +}; + +/* + * The WDT card needs to learn about soft shutdowns in order to + * turn the timebomb registers off. + */ + +static struct notifier_block wdt_notifier = { + .notifier_call = wdt_notify_sys, +}; + +/** + * wdt_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 wdt_exit(void) +{ + misc_deregister(&wdt_miscdev); + if (type == 501) + misc_deregister(&temp_miscdev); + unregister_reboot_notifier(&wdt_notifier); + free_irq(irq, NULL); + release_region(io, 8); +} + +/** + * wdt_init: + * + * Set up the WDT watchdog board. All we have to do is grab the + * resources we require and bitch if anyone beat us to them. + * The open() function will actually kick the board off. + */ + +static int __init wdt_init(void) +{ + int ret; + + if (type != 500 && type != 501) { + pr_err("unknown card type '%d'\n", type); + return -ENODEV; + } + + /* Check that the heartbeat value is within it's range; + if not reset to the default */ + if (wdt_set_heartbeat(heartbeat)) { + wdt_set_heartbeat(WD_TIMO); + pr_info("heartbeat value must be 0 < heartbeat < 65536, using %d\n", + WD_TIMO); + } + + if (!request_region(io, 8, "wdt501p")) { + pr_err("I/O address 0x%04x already in use\n", io); + ret = -EBUSY; + goto out; + } + + ret = request_irq(irq, wdt_interrupt, 0, "wdt501p", NULL); + if (ret) { + pr_err("IRQ %d is not free\n", irq); + goto outreg; + } + + ret = register_reboot_notifier(&wdt_notifier); + if (ret) { + pr_err("cannot register reboot notifier (err=%d)\n", ret); + goto outirq; + } + + if (type == 501) { + ret = misc_register(&temp_miscdev); + if (ret) { + pr_err("cannot register miscdev on minor=%d (err=%d)\n", + TEMP_MINOR, ret); + goto outrbt; + } + } + + ret = misc_register(&wdt_miscdev); + if (ret) { + pr_err("cannot register miscdev on minor=%d (err=%d)\n", + WATCHDOG_MINOR, ret); + goto outmisc; + } + + pr_info("WDT500/501-P driver 0.10 at 0x%04x (Interrupt %d). heartbeat=%d sec (nowayout=%d)\n", + io, irq, heartbeat, nowayout); + if (type == 501) + pr_info("Fan Tachometer is %s\n", + tachometer ? "Enabled" : "Disabled"); + return 0; + +outmisc: + if (type == 501) + misc_deregister(&temp_miscdev); +outrbt: + unregister_reboot_notifier(&wdt_notifier); +outirq: + free_irq(irq, NULL); +outreg: + release_region(io, 8); +out: + return ret; +} + +module_init(wdt_init); +module_exit(wdt_exit); + +MODULE_AUTHOR("Alan Cox"); +MODULE_DESCRIPTION("Driver for ISA ICS watchdog cards (WDT500/501)"); +MODULE_LICENSE("GPL"); |