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linux/drivers/watchdog/machzwd.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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/*
* MachZ ZF-Logic Watchdog Timer driver for Linux
*
*
* 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 author does 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.
*
* Author: Fernando Fuganti <fuganti@conectiva.com.br>
*
* Based on sbc60xxwdt.c by Jakob Oestergaard
*
*
* We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the
* following periods:
* wd#1 - 2 seconds;
* wd#2 - 7.2 ms;
* After the expiration of wd#1, it can generate a NMI, SCI, SMI, or
* a system RESET and it starts wd#2 that unconditionaly will RESET
* the system when the counter reaches zero.
*
* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/jiffies.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 <asm/io.h>
#include <asm/uaccess.h>
#include <asm/system.h>
/* ports */
#define ZF_IOBASE 0x218
#define INDEX 0x218
#define DATA_B 0x219
#define DATA_W 0x21A
#define DATA_D 0x21A
/* indexes */ /* size */
#define ZFL_VERSION 0x02 /* 16 */
#define CONTROL 0x10 /* 16 */
#define STATUS 0x12 /* 8 */
#define COUNTER_1 0x0C /* 16 */
#define COUNTER_2 0x0E /* 8 */
#define PULSE_LEN 0x0F /* 8 */
/* controls */
#define ENABLE_WD1 0x0001
#define ENABLE_WD2 0x0002
#define RESET_WD1 0x0010
#define RESET_WD2 0x0020
#define GEN_SCI 0x0100
#define GEN_NMI 0x0200
#define GEN_SMI 0x0400
#define GEN_RESET 0x0800
/* utilities */
#define WD1 0
#define WD2 1
#define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); }
#define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); }
#define zf_get_ZFL_version() zf_readw(ZFL_VERSION)
static unsigned short zf_readw(unsigned char port)
{
outb(port, INDEX);
return inw(DATA_W);
}
MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
#define PFX "machzwd"
static struct watchdog_info zf_info = {
.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.firmware_version = 1,
.identity = "ZF-Logic watchdog",
};
/*
* action refers to action taken when watchdog resets
* 0 = GEN_RESET
* 1 = GEN_SMI
* 2 = GEN_NMI
* 3 = GEN_SCI
* defaults to GEN_RESET (0)
*/
static int action = 0;
module_param(action, int, 0);
MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
static void zf_ping(unsigned long data);
static int zf_action = GEN_RESET;
static unsigned long zf_is_open;
static char zf_expect_close;
static DEFINE_SPINLOCK(zf_lock);
static DEFINE_SPINLOCK(zf_port_lock);
static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
static unsigned long next_heartbeat = 0;
/* timeout for user land heart beat (10 seconds) */
#define ZF_USER_TIMEO (HZ*10)
/* timeout for hardware watchdog (~500ms) */
#define ZF_HW_TIMEO (HZ/2)
/* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
#define ZF_CTIMEOUT 0xffff
#ifndef ZF_DEBUG
# define dprintk(format, args...)
#else
# define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __FUNCTION__, __LINE__ , ## args)
#endif
static inline void zf_set_status(unsigned char new)
{
zf_writeb(STATUS, new);
}
/* CONTROL register functions */
static inline unsigned short zf_get_control(void)
{
return zf_readw(CONTROL);
}
static inline void zf_set_control(unsigned short new)
{
zf_writew(CONTROL, new);
}
/* WD#? counter functions */
/*
* Just set counter value
*/
static inline void zf_set_timer(unsigned short new, unsigned char n)
{
switch(n){
case WD1:
zf_writew(COUNTER_1, new);
case WD2:
zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
default:
return;
}
}
/*
* stop hardware timer
*/
static void zf_timer_off(void)
{
unsigned int ctrl_reg = 0;
unsigned long flags;
/* stop internal ping */
del_timer_sync(&zf_timer);
spin_lock_irqsave(&zf_port_lock, flags);
/* stop watchdog timer */
ctrl_reg = zf_get_control();
ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */
ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
zf_set_control(ctrl_reg);
spin_unlock_irqrestore(&zf_port_lock, flags);
printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
}
/*
* start hardware timer
*/
static void zf_timer_on(void)
{
unsigned int ctrl_reg = 0;
unsigned long flags;
spin_lock_irqsave(&zf_port_lock, flags);
zf_writeb(PULSE_LEN, 0xff);
zf_set_timer(ZF_CTIMEOUT, WD1);
/* user land ping */
next_heartbeat = jiffies + ZF_USER_TIMEO;
/* start the timer for internal ping */
mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
/* start watchdog timer */
ctrl_reg = zf_get_control();
ctrl_reg |= (ENABLE_WD1|zf_action);
zf_set_control(ctrl_reg);
spin_unlock_irqrestore(&zf_port_lock, flags);
printk(KERN_INFO PFX ": Watchdog timer is now enabled\n");
}
static void zf_ping(unsigned long data)
{
unsigned int ctrl_reg = 0;
unsigned long flags;
zf_writeb(COUNTER_2, 0xff);
if(time_before(jiffies, next_heartbeat)){
dprintk("time_before: %ld\n", next_heartbeat - jiffies);
/*
* reset event is activated by transition from 0 to 1 on
* RESET_WD1 bit and we assume that it is already zero...
*/
spin_lock_irqsave(&zf_port_lock, flags);
ctrl_reg = zf_get_control();
ctrl_reg |= RESET_WD1;
zf_set_control(ctrl_reg);
/* ...and nothing changes until here */
ctrl_reg &= ~(RESET_WD1);
zf_set_control(ctrl_reg);
spin_unlock_irqrestore(&zf_port_lock, flags);
mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
}else{
printk(KERN_CRIT PFX ": I will reset your machine\n");
}
}
static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
loff_t *ppos)
{
/* See if we got the magic character */
if(count){
/*
* no need to check for close confirmation
* no way to disable watchdog ;)
*/
if (!nowayout) {
size_t ofs;
/*
* note: just in case someone wrote the magic character
* five months ago...
*/
zf_expect_close = 0;
/* now scan */
for (ofs = 0; ofs != count; ofs++){
char c;
if (get_user(c, buf + ofs))
return -EFAULT;
if (c == 'V'){
zf_expect_close = 42;
dprintk("zf_expect_close = 42\n");
}
}
}
/*
* Well, anyhow someone wrote to us,
* we should return that favour
*/
next_heartbeat = jiffies + ZF_USER_TIMEO;
dprintk("user ping at %ld\n", jiffies);
}
return count;
}
static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
return -EFAULT;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_KEEPALIVE:
zf_ping(0);
break;
default:
return -ENOTTY;
}
return 0;
}
static int zf_open(struct inode *inode, struct file *file)
{
spin_lock(&zf_lock);
if(test_and_set_bit(0, &zf_is_open)) {
spin_unlock(&zf_lock);
return -EBUSY;
}
if (nowayout)
__module_get(THIS_MODULE);
spin_unlock(&zf_lock);
zf_timer_on();
return nonseekable_open(inode, file);
}
static int zf_close(struct inode *inode, struct file *file)
{
if(zf_expect_close == 42){
zf_timer_off();
} else {
del_timer(&zf_timer);
printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n");
}
spin_lock(&zf_lock);
clear_bit(0, &zf_is_open);
spin_unlock(&zf_lock);
zf_expect_close = 0;
return 0;
}
/*
* Notifier for system down
*/
static int zf_notify_sys(struct notifier_block *this, unsigned long code,
void *unused)
{
if(code == SYS_DOWN || code == SYS_HALT){
zf_timer_off();
}
return NOTIFY_DONE;
}
static const struct file_operations zf_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = zf_write,
.ioctl = zf_ioctl,
.open = zf_open,
.release = zf_close,
};
static struct miscdevice zf_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &zf_fops,
};
/*
* The device needs to learn about soft shutdowns in order to
* turn the timebomb registers off.
*/
static struct notifier_block zf_notifier = {
.notifier_call = zf_notify_sys,
};
static void __init zf_show_action(int act)
{
char *str[] = { "RESET", "SMI", "NMI", "SCI" };
printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
}
static int __init zf_init(void)
{
int ret;
printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n");
ret = zf_get_ZFL_version();
if ((!ret) || (ret == 0xffff)) {
printk(KERN_WARNING PFX ": no ZF-Logic found\n");
return -ENODEV;
}
if((action <= 3) && (action >= 0)){
zf_action = zf_action>>action;
} else
action = 0;
zf_show_action(action);
if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
printk(KERN_ERR "cannot reserve I/O ports at %d\n",
ZF_IOBASE);
ret = -EBUSY;
goto no_region;
}
ret = register_reboot_notifier(&zf_notifier);
if(ret){
printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
ret);
goto no_reboot;
}
ret = misc_register(&zf_miscdev);
if (ret){
printk(KERN_ERR "can't misc_register on minor=%d\n",
WATCHDOG_MINOR);
goto no_misc;
}
zf_set_status(0);
zf_set_control(0);
return 0;
no_misc:
unregister_reboot_notifier(&zf_notifier);
no_reboot:
release_region(ZF_IOBASE, 3);
no_region:
return ret;
}
static void __exit zf_exit(void)
{
zf_timer_off();
misc_deregister(&zf_miscdev);
unregister_reboot_notifier(&zf_notifier);
release_region(ZF_IOBASE, 3);
}
module_init(zf_init);
module_exit(zf_exit);
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