--- /dev/null
+This generic GPIO watchdog is used on Huawei E970 (brcm47xx)
+
+Signed-off-by: Mathias Adam <m.adam--openwrt@adamis.de>
+
+--- a/drivers/watchdog/Kconfig
++++ b/drivers/watchdog/Kconfig
+@@ -1035,6 +1035,15 @@ config WDT_MTX1
+ Hardware driver for the MTX-1 boards. This is a watchdog timer that
+ will reboot the machine after a 100 seconds timer expired.
+
++config GPIO_WDT
++ tristate "GPIO Hardware Watchdog"
++ help
++ Hardware driver for GPIO-controlled watchdogs. GPIO pin and
++ toggle interval settings are platform-specific. The driver
++ will stop toggling the GPIO (i.e. machine reboots) after a
++ 100 second timer expired and no process has written to
++ /dev/watchdog during that time.
++
+ config PNX833X_WDT
+ tristate "PNX833x Hardware Watchdog"
+ depends on SOC_PNX8335
+--- a/drivers/watchdog/Makefile
++++ b/drivers/watchdog/Makefile
+@@ -127,6 +127,7 @@ obj-$(CONFIG_RC32434_WDT) += rc32434_wdt
+ obj-$(CONFIG_INDYDOG) += indydog.o
+ obj-$(CONFIG_JZ4740_WDT) += jz4740_wdt.o
+ obj-$(CONFIG_WDT_MTX1) += mtx-1_wdt.o
++obj-$(CONFIG_GPIO_WDT) += gpio_wdt.o
+ obj-$(CONFIG_PNX833X_WDT) += pnx833x_wdt.o
+ obj-$(CONFIG_SIBYTE_WDOG) += sb_wdog.o
+ obj-$(CONFIG_AR7_WDT) += ar7_wdt.o
+--- /dev/null
++++ b/drivers/watchdog/gpio_wdt.c
+@@ -0,0 +1,301 @@
++/*
++ * Driver for GPIO-controlled Hardware Watchdogs.
++ *
++ * Copyright (C) 2013 Mathias Adam <m.adam--linux@adamis.de>
++ *
++ * Replaces mtx1_wdt (driver for the MTX-1 Watchdog):
++ *
++ * (C) Copyright 2005 4G Systems <info@4g-systems.biz>,
++ * All Rights Reserved.
++ * http://www.4g-systems.biz
++ *
++ * (C) Copyright 2007 OpenWrt.org, Florian Fainelli <florian@openwrt.org>
++ *
++ * 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.
++ *
++ * Neither Michael Stickel nor 4G Systems admit liability nor provide
++ * warranty for any of this software. This material is provided
++ * "AS-IS" and at no charge.
++ *
++ * (c) Copyright 2005 4G Systems <info@4g-systems.biz>
++ *
++ * Release 0.01.
++ * Author: Michael Stickel michael.stickel@4g-systems.biz
++ *
++ * Release 0.02.
++ * Author: Florian Fainelli florian@openwrt.org
++ * use the Linux watchdog/timer APIs
++ *
++ * Release 0.03.
++ * Author: Mathias Adam <m.adam--linux@adamis.de>
++ * make it a generic gpio watchdog driver
++ *
++ * The Watchdog is configured to reset the MTX-1
++ * if it is not triggered for 100 seconds.
++ * It should not be triggered more often than 1.6 seconds.
++ *
++ * A timer triggers the watchdog every 5 seconds, until
++ * it is opened for the first time. After the first open
++ * it MUST be triggered every 2..95 seconds.
++ */
++
++#include <linux/module.h>
++#include <linux/moduleparam.h>
++#include <linux/types.h>
++#include <linux/errno.h>
++#include <linux/miscdevice.h>
++#include <linux/fs.h>
++#include <linux/init.h>
++#include <linux/ioport.h>
++#include <linux/timer.h>
++#include <linux/completion.h>
++#include <linux/jiffies.h>
++#include <linux/watchdog.h>
++#include <linux/platform_device.h>
++#include <linux/io.h>
++#include <linux/uaccess.h>
++#include <linux/gpio.h>
++#include <linux/gpio_wdt.h>
++
++static int ticks = 100 * HZ;
++
++static struct {
++ struct completion stop;
++ spinlock_t lock;
++ int running;
++ struct timer_list timer;
++ int queue;
++ int default_ticks;
++ unsigned long inuse;
++ unsigned gpio;
++ unsigned int gstate;
++ int interval;
++ int first_interval;
++} gpio_wdt_device;
++
++static void gpio_wdt_trigger(unsigned long unused)
++{
++ spin_lock(&gpio_wdt_device.lock);
++ if (gpio_wdt_device.running && ticks > 0)
++ ticks -= gpio_wdt_device.interval;
++
++ /* toggle wdt gpio */
++ gpio_wdt_device.gstate = !gpio_wdt_device.gstate;
++ gpio_set_value(gpio_wdt_device.gpio, gpio_wdt_device.gstate);
++
++ if (gpio_wdt_device.queue && ticks > 0)
++ mod_timer(&gpio_wdt_device.timer, jiffies + gpio_wdt_device.interval);
++ else
++ complete(&gpio_wdt_device.stop);
++ spin_unlock(&gpio_wdt_device.lock);
++}
++
++static void gpio_wdt_reset(void)
++{
++ ticks = gpio_wdt_device.default_ticks;
++}
++
++
++static void gpio_wdt_start(void)
++{
++ unsigned long flags;
++
++ spin_lock_irqsave(&gpio_wdt_device.lock, flags);
++ if (!gpio_wdt_device.queue) {
++ gpio_wdt_device.queue = 1;
++ gpio_wdt_device.gstate = 1;
++ gpio_set_value(gpio_wdt_device.gpio, 1);
++ mod_timer(&gpio_wdt_device.timer, jiffies + gpio_wdt_device.first_interval);
++ }
++ gpio_wdt_device.running++;
++ spin_unlock_irqrestore(&gpio_wdt_device.lock, flags);
++}
++
++static int gpio_wdt_stop(void)
++{
++ unsigned long flags;
++
++ spin_lock_irqsave(&gpio_wdt_device.lock, flags);
++ if (gpio_wdt_device.queue) {
++ gpio_wdt_device.queue = 0;
++ gpio_wdt_device.gstate = 0;
++ gpio_set_value(gpio_wdt_device.gpio, 0);
++ }
++ ticks = gpio_wdt_device.default_ticks;
++ spin_unlock_irqrestore(&gpio_wdt_device.lock, flags);
++ return 0;
++}
++
++/* Filesystem functions */
++
++static int gpio_wdt_open(struct inode *inode, struct file *file)
++{
++ if (test_and_set_bit(0, &gpio_wdt_device.inuse))
++ return -EBUSY;
++ return nonseekable_open(inode, file);
++}
++
++
++static int gpio_wdt_release(struct inode *inode, struct file *file)
++{
++ clear_bit(0, &gpio_wdt_device.inuse);
++ return 0;
++}
++
++static long gpio_wdt_ioctl(struct file *file, unsigned int cmd,
++ unsigned long arg)
++{
++ void __user *argp = (void __user *)arg;
++ int __user *p = (int __user *)argp;
++ unsigned int value;
++ static const struct watchdog_info ident = {
++ .options = WDIOF_CARDRESET,
++ .identity = "GPIO WDT",
++ };
++
++ switch (cmd) {
++ case WDIOC_GETSUPPORT:
++ if (copy_to_user(argp, &ident, sizeof(ident)))
++ return -EFAULT;
++ break;
++ case WDIOC_GETSTATUS:
++ case WDIOC_GETBOOTSTATUS:
++ put_user(0, p);
++ break;
++ case WDIOC_SETOPTIONS:
++ if (get_user(value, p))
++ return -EFAULT;
++ if (value & WDIOS_ENABLECARD)
++ gpio_wdt_start();
++ else if (value & WDIOS_DISABLECARD)
++ gpio_wdt_stop();
++ else
++ return -EINVAL;
++ return 0;
++ case WDIOC_KEEPALIVE:
++ gpio_wdt_reset();
++ break;
++ default:
++ return -ENOTTY;
++ }
++ return 0;
++}
++
++
++static ssize_t gpio_wdt_write(struct file *file, const char *buf,
++ size_t count, loff_t *ppos)
++{
++ if (!count)
++ return -EIO;
++ gpio_wdt_reset();
++ return count;
++}
++
++static const struct file_operations gpio_wdt_fops = {
++ .owner = THIS_MODULE,
++ .llseek = no_llseek,
++ .unlocked_ioctl = gpio_wdt_ioctl,
++ .open = gpio_wdt_open,
++ .write = gpio_wdt_write,
++ .release = gpio_wdt_release,
++};
++
++
++static struct miscdevice gpio_wdt_misc = {
++ .minor = WATCHDOG_MINOR,
++ .name = "watchdog",
++ .fops = &gpio_wdt_fops,
++};
++
++
++static int gpio_wdt_probe(struct platform_device *pdev)
++{
++ int ret;
++ struct gpio_wdt_platform_data *gpio_wdt_data = pdev->dev.platform_data;
++
++ gpio_wdt_device.gpio = gpio_wdt_data->gpio;
++ gpio_wdt_device.interval = gpio_wdt_data->interval;
++ gpio_wdt_device.first_interval = gpio_wdt_data->first_interval;
++ if (gpio_wdt_device.first_interval <= 0) {
++ gpio_wdt_device.first_interval = gpio_wdt_device.interval;
++ }
++
++ ret = gpio_request(gpio_wdt_device.gpio, "gpio-wdt");
++ if (ret < 0) {
++ dev_err(&pdev->dev, "failed to request gpio");
++ return ret;
++ }
++
++ spin_lock_init(&gpio_wdt_device.lock);
++ init_completion(&gpio_wdt_device.stop);
++ gpio_wdt_device.queue = 0;
++ clear_bit(0, &gpio_wdt_device.inuse);
++ setup_timer(&gpio_wdt_device.timer, gpio_wdt_trigger, 0L);
++ gpio_wdt_device.default_ticks = ticks;
++
++ gpio_wdt_start();
++ dev_info(&pdev->dev, "GPIO Hardware Watchdog driver (gpio=%i interval=%i/%i)\n",
++ gpio_wdt_data->gpio, gpio_wdt_data->first_interval, gpio_wdt_data->interval);
++ return 0;
++}
++
++static int gpio_wdt_remove(struct platform_device *pdev)
++{
++ /* FIXME: do we need to lock this test ? */
++ if (gpio_wdt_device.queue) {
++ gpio_wdt_device.queue = 0;
++ wait_for_completion(&gpio_wdt_device.stop);
++ }
++
++ gpio_free(gpio_wdt_device.gpio);
++ misc_deregister(&gpio_wdt_misc);
++ return 0;
++}
++
++static struct platform_driver gpio_wdt_driver = {
++ .probe = gpio_wdt_probe,
++ .remove = gpio_wdt_remove,
++ .driver.name = "gpio-wdt",
++ .driver.owner = THIS_MODULE,
++};
++
++static int __init gpio_wdt_init(void)
++{
++ return platform_driver_register(&gpio_wdt_driver);
++}
++arch_initcall(gpio_wdt_init);
++
++/*
++ * We do wdt initialization in two steps: arch_initcall probes the wdt
++ * very early to start pinging the watchdog (misc devices are not yet
++ * available), and later module_init() just registers the misc device.
++ */
++static int gpio_wdt_init_late(void)
++{
++ int ret;
++
++ ret = misc_register(&gpio_wdt_misc);
++ if (ret < 0) {
++ pr_err("GPIO_WDT: failed to register misc device\n");
++ return ret;
++ }
++ return 0;
++}
++#ifndef MODULE
++module_init(gpio_wdt_init_late);
++#endif
++
++static void __exit gpio_wdt_exit(void)
++{
++ platform_driver_unregister(&gpio_wdt_driver);
++}
++module_exit(gpio_wdt_exit);
++
++MODULE_AUTHOR("Michael Stickel, Florian Fainelli, Mathias Adam");
++MODULE_DESCRIPTION("Driver for GPIO hardware watchdogs");
++MODULE_LICENSE("GPL");
++MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
++MODULE_ALIAS("platform:gpio-wdt");
+--- /dev/null
++++ b/include/linux/gpio_wdt.h
+@@ -0,0 +1,21 @@
++/*
++ * Definitions for the GPIO watchdog driver
++ *
++ * Copyright (C) 2013 Mathias Adam <m.adam--linux@adamis.de>
++ *
++ * This program is free software; you can redistribute it and/or modify
++ * it under the terms of the GNU General Public License version 2 as
++ * published by the Free Software Foundation.
++ *
++ */
++
++#ifndef _GPIO_WDT_H_
++#define _GPIO_WDT_H_
++
++struct gpio_wdt_platform_data {
++ int gpio; /* GPIO line number */
++ int interval; /* watchdog reset interval in system ticks */
++ int first_interval; /* first wd reset interval in system ticks */
++};
++
++#endif /* _GPIO_WDT_H_ */
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