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kernel-fxtec-pro1x/drivers/watchdog/smsc37b787_wdt.c
Alexey Dobriyan c7dfd0cca3 [WATCHDOG] spin_lock_init() fixes 
Some watchdog drivers initialize global spinlocks in module's init function
which is tolerable, but some do it in PCI probe function.  So, switch to
static initialization to fix theoretical bugs and, more importantly, stop
giving people bad examples.

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-11-02 19:09:07 +00:00

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/*
* 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 DEFINE_SPINLOCK(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 const 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;
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) ")");
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