linux-imx

/*

 *  ALi M7101 PMU Computer Watchdog Timer driver

 *

 *  Based on w83877f_wdt.c by Scott Jennings <linuxdrivers@oro.net>

 *  and the Cobalt kernel WDT timer driver by Tim Hockin

 *                                        <thockin@cobaltnet.com>

 *

 *  (c)2002 Steve Hill <steve@navaho.co.uk>

 *

 *  This WDT driver is different from most other Linux WDT

 *  drivers in that the driver will ping the watchdog by itself,

 *  because this particular WDT has a very short timeout (1.6

 *  seconds) and it would be insane to count on any userspace

 *  daemon always getting scheduled within that time frame.

 *

 *  Additions:

 *   Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs

 *                  found on very old cobalt hardware.

 *                  -- Mike Waychison <michael.waychison@sun.com>

 */

​

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

​

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/types.h>

#include <linux/timer.h>

#include <linux/miscdevice.h>

#include <linux/watchdog.h>

#include <linux/ioport.h>

#include <linux/notifier.h>

#include <linux/reboot.h>

#include <linux/init.h>

#include <linux/fs.h>

#include <linux/pci.h>

#include <linux/io.h>

#include <linux/uaccess.h>

​

​

#define WDT_ENABLE 0x9C

#define WDT_DISABLE 0x8C

​

#define ALI_7101_WDT    0x92

#define ALI_7101_GPIO   0x7D

#define ALI_7101_GPIO_O 0x7E

#define ALI_WDT_ARM     0x01

​

/*

 * We're going to use a 1 second timeout.

 * If we reset the watchdog every ~250ms we should be safe.  */

​

#define WDT_INTERVAL (HZ/4+1)

​

/*

 * We must not require too good response from the userspace daemon.

 * Here we require the userspace daemon to send us a heartbeat

 * char to /dev/watchdog every 30 seconds.

 */

​

#define WATCHDOG_TIMEOUT 30            /* 30 sec default timeout */

/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */

static int timeout = WATCHDOG_TIMEOUT;

module_param(timeout, int, 0);