--- /dev/null
+/*
+ * SMsC 37B787 Watchdog Timer driver for Linux 2.6.x.x
+ *
+ * Based on acquirewdt.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
+ * 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/wdt.txt
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#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 <linux/io.h>
+#include <linux/uaccess.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 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; /* is the timer enabled? */
+
+static char expect_close; /* is the close expected? */
+
+static DEFINE_SPINLOCK(io_lock);/* to guard the watchdog from io races */
+
+static bool 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 occurred
+ * 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();
+
+ pr_info("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();
+ pr_info("Watchdog disabled, sleeping again...\n");
+ } else {
+ pr_crit("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 long wb_smsc_wdt_ioctl(struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ int new_timeout;
+
+ union {
+ struct watchdog_info __user *ident;
+ int __user *i;
+ } uarg;
+
+ static const 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) {
+ 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_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;
+ }
+ 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);
+ default:
+ return -ENOTTY;
+ }
+}
+
+/* -- 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 const struct file_operations wb_smsc_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = wb_smsc_wdt_write,
+ .unlocked_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;
+
+ pr_info("SMsC 37B787 watchdog component driver "
+ VERSION " initialising...\n");
+
+ if (!request_region(IOPORT, IOPORT_SIZE, "SMsC 37B787 watchdog")) {
+ pr_err("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) {
+ pr_err("Unable to register reboot notifier err = %d\n", ret);
+ goto out_io;
+ }
+
+ ret = misc_register(&wb_smsc_wdt_miscdev);
+ if (ret) {
+ pr_err("Unable to register miscdev on minor %d\n",
+ WATCHDOG_MINOR);
+ goto out_rbt;
+ }
+
+ /* output info */
+ pr_info("Timeout set to %d %s\n",
+ timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
+ pr_info("Watchdog initialized and sleeping (nowayout=%d)...\n",
+ nowayout);
+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();
+ pr_info("Watchdog disabled\n");
+ }
+
+ misc_deregister(&wb_smsc_wdt_miscdev);
+ unregister_reboot_notifier(&wb_smsc_wdt_notifier);
+ release_region(IOPORT, IOPORT_SIZE);
+
+ pr_info("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");
+
+#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, bool, 0);
+MODULE_PARM_DESC(nowayout,
+ "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Code Review / kvmfornfv.git / blobdiff