// SPDX-License-Identifier: GPL-2.0+
/*
* 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>
* (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
*
* 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/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 <asm/mach-au1x00/au1000.h>
#define MTX1_WDT_INTERVAL (5 * HZ)
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;
} mtx1_wdt_device;
static void mtx1_wdt_trigger(struct timer_list *unused)
{
spin_lock(&mtx1_wdt_device.lock);
if (mtx1_wdt_device.running)
ticks--;
/* toggle wdt gpio */
mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate;
gpio_set_value(mtx1_wdt_device.gpio, mtx1_wdt_device.gstate);
if (mtx1_wdt_device.queue && ticks)
mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
else
complete(&mtx1_wdt_device.stop);
spin_unlock(&mtx1_wdt_device.lock);
}
static void mtx1_wdt_reset(void)
{
ticks = mtx1_wdt_device.default_ticks;
}
static void mtx1_wdt_start(void)
{
unsigned long flags;
spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
if (!mtx1_wdt_device.queue) {
mtx1_wdt_device.queue = 1;
mtx1_wdt_device.gstate = 1;
gpio_set_value(mtx1_wdt_device.gpio, 1);
mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
}
mtx1_wdt_device.running++;
spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
}
static int mtx1_wdt_stop(void)
{
unsigned long flags;
spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
if (mtx1_wdt_device.queue) {
mtx1_wdt_device.queue = 0;
mtx1_wdt_device.gstate = 0;
gpio_set_value(mtx1_wdt_device.gpio, 0);
}
ticks = mtx1_wdt_device.default_ticks;
spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
return 0;
}
/* Filesystem functions */
static int mtx1_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
return -EBUSY;
return nonseekable_open(inode, file);
}
static int mtx1_wdt_release(struct inode *inode, struct file *file)
{
clear_bit(0, &mtx1_wdt_device.inuse);
return 0;
}
static long mtx1_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 = "MTX-1 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)
mtx1_wdt_start();
else if (value & WDIOS_DISABLECARD)
mtx1_wdt_stop();
else
return -EINVAL;
return 0;
case WDIOC_KEEPALIVE:
mtx1_wdt_reset();
break;
default:
return -ENOTTY;
}
return 0;
}
static ssize_t mtx1_wdt_write(struct file *file, const char *buf,
size_t count, loff_t *ppos)
{
if (!count)
return -EIO;
mtx1_wdt_reset();
return count;
}
static const struct file_operations mtx1_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.unlocked_ioctl = mtx1_wdt_ioctl,
.open = mtx1_wdt_open,
.write = mtx1_wdt_write,
.release = mtx1_wdt_release,
};
static struct miscdevice mtx1_wdt_misc = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &mtx1_wdt_fops,
};
static int mtx1_wdt_probe(struct platform_device *pdev)
{
int ret;
mtx1_wdt_device.gpio = pdev->resource[0].start;
ret = devm_gpio_request_one(&pdev->dev, mtx1_wdt_device.gpio,
GPIOF_OUT_INIT_HIGH, "mtx1-wdt");
if (ret < 0) {
dev_err(&pdev->dev, "failed to request gpio");
return ret;
}
spin_lock_init(&mtx1_wdt_device.lock);
init_completion(&mtx1_wdt_device.stop);
mtx1_wdt_device.queue = 0;
clear_bit(0, &mtx1_wdt_device.inuse);
timer_setup(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0);
mtx1_wdt_device.default_ticks = ticks;
ret = misc_register(&mtx1_wdt_misc);
if (ret < 0) {
dev_err(&pdev->dev, "failed to register\n");
return ret;
}
mtx1_wdt_start();
dev_info(&pdev->dev, "MTX-1 Watchdog driver\n");
return 0;
}
static int mtx1_wdt_remove(struct platform_device *pdev)
{
/* FIXME: do we need to lock this test ? */
if (mtx1_wdt_device.queue) {
mtx1_wdt_device.queue = 0;
wait_for_completion(&mtx1_wdt_device.stop);
}
misc_deregister(&mtx1_wdt_misc);
return 0;
}
static struct platform_driver mtx1_wdt_driver = {
.probe = mtx1_wdt_probe,
.remove = mtx1_wdt_remove,
.driver.name = "mtx1-wdt",
.driver.owner = THIS_MODULE,
};
module_platform_driver(mtx1_wdt_driver);
MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:mtx1-wdt");
