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linux/drivers/watchdog/mtx-1_wdt.c
Al Viro cb787f4ac0 [tree-wide] finally take no_llseek out
no_llseek had been defined to NULL two years ago, in commit 868941b144
("fs: remove no_llseek")

To quote that commit,

  At -rc1 we'll need do a mechanical removal of no_llseek -

  git grep -l -w no_llseek | grep -v porting.rst | while read i; do
	sed -i '/\<no_llseek\>/d' $i
  done

  would do it.

Unfortunately, that hadn't been done.  Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
	.llseek = no_llseek,
so it's obviously safe.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-09-27 08:18:43 -07:00

246 lines
5.8 KiB
C

// 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/consumer.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;
struct gpio_desc *gpiod;
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;
gpiod_set_value(mtx1_wdt_device.gpiod, 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;
gpiod_set_value(mtx1_wdt_device.gpiod, 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;
gpiod_set_value(mtx1_wdt_device.gpiod, 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 stream_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,
.unlocked_ioctl = mtx1_wdt_ioctl,
.compat_ioctl = compat_ptr_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.gpiod = devm_gpiod_get(&pdev->dev,
NULL, GPIOD_OUT_HIGH);
if (IS_ERR(mtx1_wdt_device.gpiod)) {
dev_err(&pdev->dev, "failed to request gpio");
return PTR_ERR(mtx1_wdt_device.gpiod);
}
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 void 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);
}
static struct platform_driver mtx1_wdt_driver = {
.probe = mtx1_wdt_probe,
.remove_new = mtx1_wdt_remove,
.driver.name = "mtx1-wdt",
};
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");