| /* |
| * SMsC 37B787 Watchdog Timer driver for Linux 2.6.x.x |
| * |
| * Based on acquirewdt.c by Alan Cox <alan@redhat.com> |
| * and some other existing drivers |
| * |
| * 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 authors do 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. |
| * |
| * (C) Copyright 2003-2006 Sven Anders <anders@anduras.de> |
| * |
| * History: |
| * 2003 - Created version 1.0 for Linux 2.4.x. |
| * 2006 - Ported to Linux 2.6, added nowayout and MAGICCLOSE |
| * features. Released version 1.1 |
| * |
| * Theory of operation: |
| * |
| * A Watchdog Timer (WDT) is a hardware circuit that can |
| * reset the computer system in case of a software fault. |
| * You probably knew that already. |
| * |
| * Usually a userspace daemon will notify the kernel WDT driver |
| * via the /dev/watchdog special device file that userspace is |
| * still alive, at regular intervals. When such a notification |
| * occurs, the driver will usually tell the hardware watchdog |
| * that everything is in order, and that the watchdog should wait |
| * for yet another little while to reset the system. |
| * If userspace fails (RAM error, kernel bug, whatever), the |
| * notifications cease to occur, and the hardware watchdog will |
| * reset the system (causing a reboot) after the timeout occurs. |
| * |
| * Create device with: |
| * mknod /dev/watchdog c 10 130 |
| * |
| * For an example userspace keep-alive daemon, see: |
| * Documentation/watchdog/watchdog.txt |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/moduleparam.h> |
| #include <linux/types.h> |
| #include <linux/miscdevice.h> |
| #include <linux/watchdog.h> |
| #include <linux/delay.h> |
| #include <linux/fs.h> |
| #include <linux/ioport.h> |
| #include <linux/notifier.h> |
| #include <linux/reboot.h> |
| #include <linux/init.h> |
| #include <linux/spinlock.h> |
| |
| #include <asm/io.h> |
| #include <asm/uaccess.h> |
| #include <asm/system.h> |
| |
| /* enable support for minutes as units? */ |
| /* (does not always work correctly, so disabled by default!) */ |
| #define SMSC_SUPPORT_MINUTES |
| #undef SMSC_SUPPORT_MINUTES |
| |
| #define MAX_TIMEOUT 255 |
| |
| #define UNIT_SECOND 0 |
| #define UNIT_MINUTE 1 |
| |
| #define MODNAME "smsc37b787_wdt: " |
| #define VERSION "1.1" |
| |
| #define IOPORT 0x3F0 |
| #define IOPORT_SIZE 2 |
| #define IODEV_NO 8 |
| |
| static int unit = UNIT_SECOND; /* timer's unit */ |
| static int timeout = 60; /* timeout value: default is 60 "units" */ |
| static unsigned long timer_enabled = 0; /* is the timer enabled? */ |
| |
| static char expect_close; /* is the close expected? */ |
| |
| static spinlock_t io_lock; /* to guard the watchdog from io races */ |
| |
| static int nowayout = WATCHDOG_NOWAYOUT; |
| |
| /* -- Low level function ----------------------------------------*/ |
| |
| /* unlock the IO chip */ |
| |
| static inline void open_io_config(void) |
| { |
| outb(0x55, IOPORT); |
| mdelay(1); |
| outb(0x55, IOPORT); |
| } |
| |
| /* lock the IO chip */ |
| static inline void close_io_config(void) |
| { |
| outb(0xAA, IOPORT); |
| } |
| |
| /* select the IO device */ |
| static inline void select_io_device(unsigned char devno) |
| { |
| outb(0x07, IOPORT); |
| outb(devno, IOPORT+1); |
| } |
| |
| /* write to the control register */ |
| static inline void write_io_cr(unsigned char reg, unsigned char data) |
| { |
| outb(reg, IOPORT); |
| outb(data, IOPORT+1); |
| } |
| |
| /* read from the control register */ |
| static inline char read_io_cr(unsigned char reg) |
| { |
| outb(reg, IOPORT); |
| return inb(IOPORT+1); |
| } |
| |
| /* -- Medium level functions ------------------------------------*/ |
| |
| static inline void gpio_bit12(unsigned char reg) |
| { |
| // -- General Purpose I/O Bit 1.2 -- |
| // Bit 0, In/Out: 0 = Output, 1 = Input |
| // Bit 1, Polarity: 0 = No Invert, 1 = Invert |
| // Bit 2, Group Enable Intr.: 0 = Disable, 1 = Enable |
| // Bit 3/4, Function select: 00 = GPI/O, 01 = WDT, 10 = P17, |
| // 11 = Either Edge Triggered Intr. 2 |
| // Bit 5/6 (Reserved) |
| // Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain |
| write_io_cr(0xE2, reg); |
| } |
| |
| static inline void gpio_bit13(unsigned char reg) |
| { |
| // -- General Purpose I/O Bit 1.3 -- |
| // Bit 0, In/Out: 0 = Output, 1 = Input |
| // Bit 1, Polarity: 0 = No Invert, 1 = Invert |
| // Bit 2, Group Enable Intr.: 0 = Disable, 1 = Enable |
| // Bit 3, Function select: 0 = GPI/O, 1 = LED |
| // Bit 4-6 (Reserved) |
| // Bit 7, Output Type: 0 = Push Pull Bit, 1 = Open Drain |
| write_io_cr(0xE3, reg); |
| } |
| |
| static inline void wdt_timer_units(unsigned char new_units) |
| { |
| // -- Watchdog timer units -- |
| // Bit 0-6 (Reserved) |
| // Bit 7, WDT Time-out Value Units Select |
| // (0 = Minutes, 1 = Seconds) |
| write_io_cr(0xF1, new_units); |
| } |
| |
| static inline void wdt_timeout_value(unsigned char new_timeout) |
| { |
| // -- Watchdog Timer Time-out Value -- |
| // Bit 0-7 Binary coded units (0=Disabled, 1..255) |
| write_io_cr(0xF2, new_timeout); |
| } |
| |
| static inline void wdt_timer_conf(unsigned char conf) |
| { |
| // -- Watchdog timer configuration -- |
| // Bit 0 Joystick enable: 0* = No Reset, 1 = Reset WDT upon Gameport I/O |
| // Bit 1 Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr. |
| // Bit 2 Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr. |
| // Bit 3 Reset the timer |
| // (Wrong in SMsC documentation? Given as: PowerLED Timout Enabled) |
| // Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled, |
| // 0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15) |
| write_io_cr(0xF3, conf); |
| } |
| |
| static inline void wdt_timer_ctrl(unsigned char reg) |
| { |
| // -- Watchdog timer control -- |
| // Bit 0 Status Bit: 0 = Timer counting, 1 = Timeout occured |
| // Bit 1 Power LED Toggle: 0 = Disable Toggle, 1 = Toggle at 1 Hz |
| // Bit 2 Force Timeout: 1 = Forces WD timeout event (self-cleaning) |
| // Bit 3 P20 Force Timeout enabled: |
| // 0 = P20 activity does not generate the WD timeout event |
| // 1 = P20 Allows rising edge of P20, from the keyboard |
| // controller, to force the WD timeout event. |
| // Bit 4 (Reserved) |
| // -- Soft power management -- |
| // Bit 5 Stop Counter: 1 = Stop software power down counter |
| // set via register 0xB8, (self-cleaning) |
| // (Upon read: 0 = Counter running, 1 = Counter stopped) |
| // Bit 6 Restart Counter: 1 = Restart software power down counter |
| // set via register 0xB8, (self-cleaning) |
| // Bit 7 SPOFF: 1 = Force software power down (self-cleaning) |
| |
| write_io_cr(0xF4, reg); |
| } |
| |
| /* -- Higher level functions ------------------------------------*/ |
| |
| /* initialize watchdog */ |
| |
| static void wb_smsc_wdt_initialize(void) |
| { |
| unsigned char old; |
| |
| spin_lock(&io_lock); |
| open_io_config(); |
| select_io_device(IODEV_NO); |
| |
| // enable the watchdog |
| gpio_bit13(0x08); // Select pin 80 = LED not GPIO |
| gpio_bit12(0x0A); // Set pin 79 = WDT not GPIO/Output/Polarity=Invert |
| |
| // disable the timeout |
| wdt_timeout_value(0); |
| |
| // reset control register |
| wdt_timer_ctrl(0x00); |
| |
| // reset configuration register |
| wdt_timer_conf(0x00); |
| |
| // read old (timer units) register |
| old = read_io_cr(0xF1) & 0x7F; |
| if (unit == UNIT_SECOND) old |= 0x80; // set to seconds |
| |
| // set the watchdog timer units |
| wdt_timer_units(old); |
| |
| close_io_config(); |
| spin_unlock(&io_lock); |
| } |
| |
| /* shutdown the watchdog */ |
| |
| static void wb_smsc_wdt_shutdown(void) |
| { |
| spin_lock(&io_lock); |
| open_io_config(); |
| select_io_device(IODEV_NO); |
| |
| // disable the watchdog |
| gpio_bit13(0x09); |
| gpio_bit12(0x09); |
| |
| // reset watchdog config register |
| wdt_timer_conf(0x00); |
| |
| // reset watchdog control register |
| wdt_timer_ctrl(0x00); |
| |
| // disable timeout |
| wdt_timeout_value(0x00); |
| |
| close_io_config(); |
| spin_unlock(&io_lock); |
| } |
| |
| /* set timeout => enable watchdog */ |
| |
| static void wb_smsc_wdt_set_timeout(unsigned char new_timeout) |
| { |
| spin_lock(&io_lock); |
| open_io_config(); |
| select_io_device(IODEV_NO); |
| |
| // set Power LED to blink, if we enable the timeout |
| wdt_timer_ctrl((new_timeout == 0) ? 0x00 : 0x02); |
| |
| // set timeout value |
| wdt_timeout_value(new_timeout); |
| |
| close_io_config(); |
| spin_unlock(&io_lock); |
| } |
| |
| /* get timeout */ |
| |
| static unsigned char wb_smsc_wdt_get_timeout(void) |
| { |
| unsigned char set_timeout; |
| |
| spin_lock(&io_lock); |
| open_io_config(); |
| select_io_device(IODEV_NO); |
| set_timeout = read_io_cr(0xF2); |
| close_io_config(); |
| spin_unlock(&io_lock); |
| |
| return set_timeout; |
| } |
| |
| /* disable watchdog */ |
| |
| static void wb_smsc_wdt_disable(void) |
| { |
| // set the timeout to 0 to disable the watchdog |
| wb_smsc_wdt_set_timeout(0); |
| } |
| |
| /* enable watchdog by setting the current timeout */ |
| |
| static void wb_smsc_wdt_enable(void) |
| { |
| // set the current timeout... |
| wb_smsc_wdt_set_timeout(timeout); |
| } |
| |
| /* reset the timer */ |
| |
| static void wb_smsc_wdt_reset_timer(void) |
| { |
| spin_lock(&io_lock); |
| open_io_config(); |
| select_io_device(IODEV_NO); |
| |
| // reset the timer |
| wdt_timeout_value(timeout); |
| wdt_timer_conf(0x08); |
| |
| close_io_config(); |
| spin_unlock(&io_lock); |
| } |
| |
| /* return, if the watchdog is enabled (timeout is set...) */ |
| |
| static int wb_smsc_wdt_status(void) |
| { |
| return (wb_smsc_wdt_get_timeout() == 0) ? 0 : WDIOF_KEEPALIVEPING; |
| } |
| |
| |
| /* -- File operations -------------------------------------------*/ |
| |
| /* open => enable watchdog and set initial timeout */ |
| |
| static int wb_smsc_wdt_open(struct inode *inode, struct file *file) |
| { |
| /* /dev/watchdog can only be opened once */ |
| |
| if (test_and_set_bit(0, &timer_enabled)) |
| return -EBUSY; |
| |
| if (nowayout) |
| __module_get(THIS_MODULE); |
| |
| /* Reload and activate timer */ |
| wb_smsc_wdt_enable(); |
| |
| printk(KERN_INFO MODNAME "Watchdog enabled. Timeout set to %d %s.\n", timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)"); |
| |
| return nonseekable_open(inode, file); |
| } |
| |
| /* close => shut off the timer */ |
| |
| static int wb_smsc_wdt_release(struct inode *inode, struct file *file) |
| { |
| /* Shut off the timer. */ |
| |
| if (expect_close == 42) { |
| wb_smsc_wdt_disable(); |
| printk(KERN_INFO MODNAME "Watchdog disabled, sleeping again...\n"); |
| } else { |
| printk(KERN_CRIT MODNAME "Unexpected close, not stopping watchdog!\n"); |
| wb_smsc_wdt_reset_timer(); |
| } |
| |
| clear_bit(0, &timer_enabled); |
| expect_close = 0; |
| return 0; |
| } |
| |
| /* write => update the timer to keep the machine alive */ |
| |
| static ssize_t wb_smsc_wdt_write(struct file *file, const char __user *data, |
| size_t len, loff_t *ppos) |
| { |
| /* See if we got the magic character 'V' and reload the timer */ |
| if (len) { |
| if (!nowayout) { |
| size_t i; |
| |
| /* reset expect flag */ |
| expect_close = 0; |
| |
| /* scan to see whether or not we got the magic character */ |
| for (i = 0; i != len; i++) { |
| char c; |
| if (get_user(c, data+i)) |
| return -EFAULT; |
| if (c == 'V') |
| expect_close = 42; |
| } |
| } |
| |
| /* someone wrote to us, we should reload the timer */ |
| wb_smsc_wdt_reset_timer(); |
| } |
| return len; |
| } |
| |
| /* ioctl => control interface */ |
| |
| static int wb_smsc_wdt_ioctl(struct inode *inode, struct file *file, |
| unsigned int cmd, unsigned long arg) |
| { |
| int new_timeout; |
| |
| union { |
| struct watchdog_info __user *ident; |
| int __user *i; |
| } uarg; |
| |
| static struct watchdog_info ident = { |
| .options = WDIOF_KEEPALIVEPING | |
| WDIOF_SETTIMEOUT | |
| WDIOF_MAGICCLOSE, |
| .firmware_version = 0, |
| .identity = "SMsC 37B787 Watchdog" |
| }; |
| |
| uarg.i = (int __user *)arg; |
| |
| switch (cmd) { |
| default: |
| return -ENOTTY; |
| |
| case WDIOC_GETSUPPORT: |
| return copy_to_user(uarg.ident, &ident, |
| sizeof(ident)) ? -EFAULT : 0; |
| |
| case WDIOC_GETSTATUS: |
| return put_user(wb_smsc_wdt_status(), uarg.i); |
| |
| case WDIOC_GETBOOTSTATUS: |
| return put_user(0, uarg.i); |
| |
| case WDIOC_KEEPALIVE: |
| wb_smsc_wdt_reset_timer(); |
| return 0; |
| |
| case WDIOC_SETTIMEOUT: |
| if (get_user(new_timeout, uarg.i)) |
| return -EFAULT; |
| |
| // the API states this is given in secs |
| if (unit == UNIT_MINUTE) |
| new_timeout /= 60; |
| |
| if (new_timeout < 0 || new_timeout > MAX_TIMEOUT) |
| return -EINVAL; |
| |
| timeout = new_timeout; |
| wb_smsc_wdt_set_timeout(timeout); |
| |
| // fall through and return the new timeout... |
| |
| case WDIOC_GETTIMEOUT: |
| |
| new_timeout = timeout; |
| |
| if (unit == UNIT_MINUTE) |
| new_timeout *= 60; |
| |
| return put_user(new_timeout, uarg.i); |
| |
| case WDIOC_SETOPTIONS: |
| { |
| int options, retval = -EINVAL; |
| |
| if (get_user(options, uarg.i)) |
| return -EFAULT; |
| |
| if (options & WDIOS_DISABLECARD) { |
| wb_smsc_wdt_disable(); |
| retval = 0; |
| } |
| |
| if (options & WDIOS_ENABLECARD) { |
| wb_smsc_wdt_enable(); |
| retval = 0; |
| } |
| |
| return retval; |
| } |
| } |
| } |
| |
| /* -- Notifier funtions -----------------------------------------*/ |
| |
| static int wb_smsc_wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) |
| { |
| if (code == SYS_DOWN || code == SYS_HALT) |
| { |
| // set timeout to 0, to avoid possible race-condition |
| timeout = 0; |
| wb_smsc_wdt_disable(); |
| } |
| return NOTIFY_DONE; |
| } |
| |
| /* -- Module's structures ---------------------------------------*/ |
| |
| static struct file_operations wb_smsc_wdt_fops = |
| { |
| .owner = THIS_MODULE, |
| .llseek = no_llseek, |
| .write = wb_smsc_wdt_write, |
| .ioctl = wb_smsc_wdt_ioctl, |
| .open = wb_smsc_wdt_open, |
| .release = wb_smsc_wdt_release, |
| }; |
| |
| static struct notifier_block wb_smsc_wdt_notifier = |
| { |
| .notifier_call = wb_smsc_wdt_notify_sys, |
| }; |
| |
| static struct miscdevice wb_smsc_wdt_miscdev = |
| { |
| .minor = WATCHDOG_MINOR, |
| .name = "watchdog", |
| .fops = &wb_smsc_wdt_fops, |
| }; |
| |
| /* -- Module init functions -------------------------------------*/ |
| |
| /* module's "constructor" */ |
| |
| static int __init wb_smsc_wdt_init(void) |
| { |
| int ret; |
| |
| spin_lock_init(&io_lock); |
| |
| printk("SMsC 37B787 watchdog component driver " VERSION " initialising...\n"); |
| |
| if (!request_region(IOPORT, IOPORT_SIZE, "SMsC 37B787 watchdog")) { |
| printk(KERN_ERR MODNAME "Unable to register IO port %#x\n", IOPORT); |
| ret = -EBUSY; |
| goto out_pnp; |
| } |
| |
| // set new maximum, if it's too big |
| if (timeout > MAX_TIMEOUT) |
| timeout = MAX_TIMEOUT; |
| |
| // init the watchdog timer |
| wb_smsc_wdt_initialize(); |
| |
| ret = register_reboot_notifier(&wb_smsc_wdt_notifier); |
| if (ret) { |
| printk(KERN_ERR MODNAME "Unable to register reboot notifier err = %d\n", ret); |
| goto out_io; |
| } |
| |
| ret = misc_register(&wb_smsc_wdt_miscdev); |
| if (ret) { |
| printk(KERN_ERR MODNAME "Unable to register miscdev on minor %d\n", WATCHDOG_MINOR); |
| goto out_rbt; |
| } |
| |
| // output info |
| printk(KERN_INFO MODNAME "Timeout set to %d %s.\n", timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)"); |
| printk(KERN_INFO MODNAME "Watchdog initialized and sleeping (nowayout=%d)...\n", nowayout); |
| |
| // ret = 0 |
| |
| out_clean: |
| return ret; |
| |
| out_rbt: |
| unregister_reboot_notifier(&wb_smsc_wdt_notifier); |
| |
| out_io: |
| release_region(IOPORT, IOPORT_SIZE); |
| |
| out_pnp: |
| goto out_clean; |
| } |
| |
| /* module's "destructor" */ |
| |
| static void __exit wb_smsc_wdt_exit(void) |
| { |
| /* Stop the timer before we leave */ |
| if (!nowayout) |
| { |
| wb_smsc_wdt_shutdown(); |
| printk(KERN_INFO MODNAME "Watchdog disabled.\n"); |
| } |
| |
| misc_deregister(&wb_smsc_wdt_miscdev); |
| unregister_reboot_notifier(&wb_smsc_wdt_notifier); |
| release_region(IOPORT, IOPORT_SIZE); |
| |
| printk("SMsC 37B787 watchdog component driver removed.\n"); |
| } |
| |
| module_init(wb_smsc_wdt_init); |
| module_exit(wb_smsc_wdt_exit); |
| |
| MODULE_AUTHOR("Sven Anders <anders@anduras.de>"); |
| MODULE_DESCRIPTION("Driver for SMsC 37B787 watchdog component (Version " VERSION ")"); |
| MODULE_LICENSE("GPL"); |
| |
| MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
| |
| #ifdef SMSC_SUPPORT_MINUTES |
| module_param(unit, int, 0); |
| MODULE_PARM_DESC(unit, "set unit to use, 0=seconds or 1=minutes, default is 0"); |
| #endif |
| |
| module_param(timeout, int, 0); |
| MODULE_PARM_DESC(timeout, "range is 1-255 units, default is 60"); |
| |
| module_param(nowayout, int, 0); |
| MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |