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linux-next/drivers/watchdog/w83977f_wdt.c
Wim Van Sebroeck c6cb13aead [WATCHDOG] misc_register patch 
Make sure that we first do a register_reboot_notifier before we
do a misc_register. A misc_register opens the interface to
userspace and it's best to do this as the last action.

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
2008-01-25 20:31:50 +00:00

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/*
* W83977F Watchdog Timer Driver for Winbond W83977F I/O Chip
*
* (c) Copyright 2005 Jose Goncalves <jose.goncalves@inov.pt>
*
* Based on w83877f_wdt.c by Scott Jennings,
* and wdt977.c by Woody Suwalski
*
* -----------------------
*
* 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.
*
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#define WATCHDOG_VERSION "1.00"
#define WATCHDOG_NAME "W83977F WDT"
#define PFX WATCHDOG_NAME ": "
#define DRIVER_VERSION WATCHDOG_NAME " driver, v" WATCHDOG_VERSION "\n"
#define IO_INDEX_PORT 0x3F0
#define IO_DATA_PORT (IO_INDEX_PORT+1)
#define UNLOCK_DATA 0x87
#define LOCK_DATA 0xAA
#define DEVICE_REGISTER 0x07
#define DEFAULT_TIMEOUT 45 /* default timeout in seconds */
static int timeout = DEFAULT_TIMEOUT;
static int timeoutW; /* timeout in watchdog counter units */
static unsigned long timer_alive;
static int testmode;
static char expect_close;
static DEFINE_SPINLOCK(spinlock);
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,"Watchdog timeout in seconds (15..7635), default=" __MODULE_STRING(DEFAULT_TIMEOUT) ")");
module_param(testmode, int, 0);
MODULE_PARM_DESC(testmode,"Watchdog testmode (1 = no reboot), default=0");
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) ")");
/*
* Start the watchdog
*/
static int wdt_start(void)
{
unsigned long flags;
spin_lock_irqsave(&spinlock, flags);
/* Unlock the SuperIO chip */
outb_p(UNLOCK_DATA,IO_INDEX_PORT);
outb_p(UNLOCK_DATA,IO_INDEX_PORT);
/*
* Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
* F2 has the timeout in watchdog counter units.
* F3 is set to enable watchdog LED blink at timeout.
* F4 is used to just clear the TIMEOUT'ed state (bit 0).
*/
outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
outb_p(0x08,IO_DATA_PORT);
outb_p(0xF2,IO_INDEX_PORT);
outb_p(timeoutW,IO_DATA_PORT);
outb_p(0xF3,IO_INDEX_PORT);
outb_p(0x08,IO_DATA_PORT);
outb_p(0xF4,IO_INDEX_PORT);
outb_p(0x00,IO_DATA_PORT);
/* Set device Aux2 active */
outb_p(0x30,IO_INDEX_PORT);
outb_p(0x01,IO_DATA_PORT);
/*
* Select device Aux1 (dev=7) to set GP16 as the watchdog output
* (in reg E6) and GP13 as the watchdog LED output (in reg E3).
* Map GP16 at pin 119.
* In test mode watch the bit 0 on F4 to indicate "triggered" or
* check watchdog LED on SBC.
*/
outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
outb_p(0x07,IO_DATA_PORT);
if (!testmode)
{
unsigned pin_map;
outb_p(0xE6,IO_INDEX_PORT);
outb_p(0x0A,IO_DATA_PORT);
outb_p(0x2C,IO_INDEX_PORT);
pin_map = inb_p(IO_DATA_PORT);
pin_map |= 0x10;
pin_map &= ~(0x20);
outb_p(0x2C,IO_INDEX_PORT);
outb_p(pin_map,IO_DATA_PORT);
}
outb_p(0xE3,IO_INDEX_PORT);
outb_p(0x08,IO_DATA_PORT);
/* Set device Aux1 active */
outb_p(0x30,IO_INDEX_PORT);
outb_p(0x01,IO_DATA_PORT);
/* Lock the SuperIO chip */
outb_p(LOCK_DATA,IO_INDEX_PORT);
spin_unlock_irqrestore(&spinlock, flags);
printk(KERN_INFO PFX "activated.\n");
return 0;
}
/*
* Stop the watchdog
*/
static int wdt_stop(void)
{
unsigned long flags;
spin_lock_irqsave(&spinlock, flags);
/* Unlock the SuperIO chip */
outb_p(UNLOCK_DATA,IO_INDEX_PORT);
outb_p(UNLOCK_DATA,IO_INDEX_PORT);
/*
* Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
* F2 is reset to its default value (watchdog timer disabled).
* F3 is reset to its default state.
* F4 clears the TIMEOUT'ed state (bit 0) - back to default.
*/
outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
outb_p(0x08,IO_DATA_PORT);
outb_p(0xF2,IO_INDEX_PORT);
outb_p(0xFF,IO_DATA_PORT);
outb_p(0xF3,IO_INDEX_PORT);
outb_p(0x00,IO_DATA_PORT);
outb_p(0xF4,IO_INDEX_PORT);
outb_p(0x00,IO_DATA_PORT);
outb_p(0xF2,IO_INDEX_PORT);
outb_p(0x00,IO_DATA_PORT);
/*
* Select device Aux1 (dev=7) to set GP16 (in reg E6) and
* Gp13 (in reg E3) as inputs.
*/
outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
outb_p(0x07,IO_DATA_PORT);
if (!testmode)
{
outb_p(0xE6,IO_INDEX_PORT);
outb_p(0x01,IO_DATA_PORT);
}
outb_p(0xE3,IO_INDEX_PORT);
outb_p(0x01,IO_DATA_PORT);
/* Lock the SuperIO chip */
outb_p(LOCK_DATA,IO_INDEX_PORT);
spin_unlock_irqrestore(&spinlock, flags);
printk(KERN_INFO PFX "shutdown.\n");
return 0;
}
/*
* Send a keepalive ping to the watchdog
* This is done by simply re-writing the timeout to reg. 0xF2
*/
static int wdt_keepalive(void)
{
unsigned long flags;
spin_lock_irqsave(&spinlock, flags);
/* Unlock the SuperIO chip */
outb_p(UNLOCK_DATA,IO_INDEX_PORT);
outb_p(UNLOCK_DATA,IO_INDEX_PORT);
/* Select device Aux2 (device=8) to kick watchdog reg F2 */
outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
outb_p(0x08,IO_DATA_PORT);
outb_p(0xF2,IO_INDEX_PORT);
outb_p(timeoutW,IO_DATA_PORT);
/* Lock the SuperIO chip */
outb_p(LOCK_DATA,IO_INDEX_PORT);
spin_unlock_irqrestore(&spinlock, flags);
return 0;
}
/*
* Set the watchdog timeout value
*/
static int wdt_set_timeout(int t)
{
int tmrval;
/*
* Convert seconds to watchdog counter time units, rounding up.
* On PCM-5335 watchdog units are 30 seconds/step with 15 sec startup
* value. This information is supplied in the PCM-5335 manual and was
* checked by me on a real board. This is a bit strange because W83977f
* datasheet says counter unit is in minutes!
*/
if (t < 15)
return -EINVAL;
tmrval = ((t + 15) + 29) / 30;
if (tmrval > 255)
return -EINVAL;
/*
* timeout is the timeout in seconds,
* timeoutW is the timeout in watchdog counter units.
*/
timeoutW = tmrval;
timeout = (timeoutW * 30) - 15;
return 0;
}
/*
* Get the watchdog status
*/
static int wdt_get_status(int *status)
{
int new_status;
unsigned long flags;
spin_lock_irqsave(&spinlock, flags);
/* Unlock the SuperIO chip */
outb_p(UNLOCK_DATA,IO_INDEX_PORT);
outb_p(UNLOCK_DATA,IO_INDEX_PORT);
/* Select device Aux2 (device=8) to read watchdog reg F4 */
outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
outb_p(0x08,IO_DATA_PORT);
outb_p(0xF4,IO_INDEX_PORT);
new_status = inb_p(IO_DATA_PORT);
/* Lock the SuperIO chip */
outb_p(LOCK_DATA,IO_INDEX_PORT);
spin_unlock_irqrestore(&spinlock, flags);
*status = 0;
if (new_status & 1)
*status |= WDIOF_CARDRESET;
return 0;
}
/*
* /dev/watchdog handling
*/
static int wdt_open(struct inode *inode, struct file *file)
{
/* If the watchdog is alive we don't need to start it again */
if( test_and_set_bit(0, &timer_alive) )
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
wdt_start();
return nonseekable_open(inode, file);
}
static int wdt_release(struct inode *inode, struct file *file)
{
/*
* Shut off the timer.
* Lock it in if it's a module and we set nowayout
*/
if (expect_close == 42)
{
wdt_stop();
clear_bit(0, &timer_alive);
} else {
wdt_keepalive();
printk(KERN_CRIT PFX "unexpected close, not stopping watchdog!\n");
}
expect_close = 0;
return 0;
}
/*
* 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)
{
/* See if we got the magic character 'V' and reload the timer */
if(count)
{
if (!nowayout)
{
size_t ofs;
/* note: just in case someone wrote the magic character long ago */
expect_close = 0;
/* scan to see whether or not we got the magic character */
for(ofs = 0; ofs != count; ofs++)
{
char c;
if (get_user(c, buf + ofs))
return -EFAULT;
if (c == 'V') {
expect_close = 42;
}
}
}
/* someone wrote to us, we should restart timer */
wdt_keepalive();
}
return count;
}
/*
* wdt_ioctl:
* @inode: inode of the device
* @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.
*/
static struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
.firmware_version = 1,
.identity = WATCHDOG_NAME,
};
static int wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int status;
int new_options, retval = -EINVAL;
int new_timeout;
union {
struct watchdog_info __user *ident;
int __user *i;
} uarg;
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:
wdt_get_status(&status);
return put_user(status, uarg.i);
case WDIOC_GETBOOTSTATUS:
return put_user(0, uarg.i);
case WDIOC_KEEPALIVE:
wdt_keepalive();
return 0;
case WDIOC_SETOPTIONS:
if (get_user (new_options, uarg.i))
return -EFAULT;
if (new_options & WDIOS_DISABLECARD) {
wdt_stop();
retval = 0;
}
if (new_options & WDIOS_ENABLECARD) {
wdt_start();
retval = 0;
}
return retval;
case WDIOC_SETTIMEOUT:
if (get_user(new_timeout, uarg.i))
return -EFAULT;
if (wdt_set_timeout(new_timeout))
return -EINVAL;
wdt_keepalive();
/* Fall */
case WDIOC_GETTIMEOUT:
return put_user(timeout, uarg.i);
}
}
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;
}
static const struct file_operations wdt_fops=
{
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = wdt_write,
.ioctl = wdt_ioctl,
.open = wdt_open,
.release = wdt_release,
};
static struct miscdevice wdt_miscdev=
{
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &wdt_fops,
};
static struct notifier_block wdt_notifier = {
.notifier_call = wdt_notify_sys,
};
static int __init w83977f_wdt_init(void)
{
int rc;
printk(KERN_INFO PFX DRIVER_VERSION);
/*
* Check that the timeout value is within it's range ;
* if not reset to the default
*/
if (wdt_set_timeout(timeout)) {
wdt_set_timeout(DEFAULT_TIMEOUT);
printk(KERN_INFO PFX "timeout value must be 15<=timeout<=7635, using %d\n",
DEFAULT_TIMEOUT);
}
if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME))
{
printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
IO_INDEX_PORT);
rc = -EIO;
goto err_out;
}
rc = register_reboot_notifier(&wdt_notifier);
if (rc)
{
printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
rc);
goto err_out_region;
}
rc = misc_register(&wdt_miscdev);
if (rc)
{
printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
wdt_miscdev.minor, rc);
goto err_out_reboot;
}
printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
timeout, nowayout, testmode);
return 0;
err_out_reboot:
unregister_reboot_notifier(&wdt_notifier);
err_out_region:
release_region(IO_INDEX_PORT,2);
err_out:
return rc;
}
static void __exit w83977f_wdt_exit(void)
{
wdt_stop();
misc_deregister(&wdt_miscdev);
unregister_reboot_notifier(&wdt_notifier);
release_region(IO_INDEX_PORT,2);
}
module_init(w83977f_wdt_init);
module_exit(w83977f_wdt_exit);
MODULE_AUTHOR("Jose Goncalves <jose.goncalves@inov.pt>");
MODULE_DESCRIPTION("Driver for watchdog timer in W83977F I/O chip");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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