linux/drivers/watchdog/advantechwdt.c
Uwe Kleine-König 8960d8ada7 watchdog: advantechwdt: Convert to platform remove callback returning void
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230303213716.2123717-4-u.kleine-koenig@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2023-04-22 12:53:40 +02:00

339 lines
7.6 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Advantech Single Board Computer WDT driver
*
* (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
*
* Based on acquirewdt.c which is based on wdt.c.
* Original copyright messages:
*
* (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
* All Rights Reserved.
*
* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
* warranty for any of this software. This material is provided
* "AS-IS" and at no charge.
*
* (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
*
* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
*
* 16-Oct-2002 Rob Radez <rob@osinvestor.com>
* Clean up ioctls, clean up init + exit, add expect close support,
* add wdt_start and wdt_stop as parameters.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/fs.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#define DRV_NAME "advantechwdt"
#define WATCHDOG_NAME "Advantech WDT"
#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
/* the watchdog platform device */
static struct platform_device *advwdt_platform_device;
static unsigned long advwdt_is_open;
static char adv_expect_close;
/*
* You must set these - there is no sane way to probe for this board.
*
* To enable or restart, write the timeout value in seconds (1 to 63)
* to I/O port wdt_start. To disable, read I/O port wdt_stop.
* Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
* check your manual (at least the PCA-6159 seems to be different -
* the manual says wdt_stop is 0x43, not 0x443).
* (0x43 is also a write-only control register for the 8254 timer!)
*/
static int wdt_stop = 0x443;
module_param(wdt_stop, int, 0);
MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
static int wdt_start = 0x443;
module_param(wdt_start, int, 0);
MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. 1<= timeout <=63, default="
__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
/*
* Watchdog Operations
*/
static void advwdt_ping(void)
{
/* Write a watchdog value */
outb_p(timeout, wdt_start);
}
static void advwdt_disable(void)
{
inb_p(wdt_stop);
}
static int advwdt_set_heartbeat(int t)
{
if (t < 1 || t > 63)
return -EINVAL;
timeout = t;
return 0;
}
/*
* /dev/watchdog handling
*/
static ssize_t advwdt_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
if (count) {
if (!nowayout) {
size_t i;
adv_expect_close = 0;
for (i = 0; i != count; i++) {
char c;
if (get_user(c, buf + i))
return -EFAULT;
if (c == 'V')
adv_expect_close = 42;
}
}
advwdt_ping();
}
return count;
}
static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int new_timeout;
void __user *argp = (void __user *)arg;
int __user *p = argp;
static const struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING |
WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE,
.firmware_version = 1,
.identity = WATCHDOG_NAME,
};
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &ident, sizeof(ident)))
return -EFAULT;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_SETOPTIONS:
{
int options, retval = -EINVAL;
if (get_user(options, p))
return -EFAULT;
if (options & WDIOS_DISABLECARD) {
advwdt_disable();
retval = 0;
}
if (options & WDIOS_ENABLECARD) {
advwdt_ping();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
advwdt_ping();
break;
case WDIOC_SETTIMEOUT:
if (get_user(new_timeout, p))
return -EFAULT;
if (advwdt_set_heartbeat(new_timeout))
return -EINVAL;
advwdt_ping();
fallthrough;
case WDIOC_GETTIMEOUT:
return put_user(timeout, p);
default:
return -ENOTTY;
}
return 0;
}
static int advwdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &advwdt_is_open))
return -EBUSY;
/*
* Activate
*/
advwdt_ping();
return stream_open(inode, file);
}
static int advwdt_close(struct inode *inode, struct file *file)
{
if (adv_expect_close == 42) {
advwdt_disable();
} else {
pr_crit("Unexpected close, not stopping watchdog!\n");
advwdt_ping();
}
clear_bit(0, &advwdt_is_open);
adv_expect_close = 0;
return 0;
}
/*
* Kernel Interfaces
*/
static const struct file_operations advwdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = advwdt_write,
.unlocked_ioctl = advwdt_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = advwdt_open,
.release = advwdt_close,
};
static struct miscdevice advwdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &advwdt_fops,
};
/*
* Init & exit routines
*/
static int __init advwdt_probe(struct platform_device *dev)
{
int ret;
if (wdt_stop != wdt_start) {
if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
pr_err("I/O address 0x%04x already in use\n",
wdt_stop);
ret = -EIO;
goto out;
}
}
if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
pr_err("I/O address 0x%04x already in use\n", wdt_start);
ret = -EIO;
goto unreg_stop;
}
/* Check that the heartbeat value is within it's range ;
* if not reset to the default */
if (advwdt_set_heartbeat(timeout)) {
advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
}
ret = misc_register(&advwdt_miscdev);
if (ret != 0) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto unreg_regions;
}
pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
timeout, nowayout);
out:
return ret;
unreg_regions:
release_region(wdt_start, 1);
unreg_stop:
if (wdt_stop != wdt_start)
release_region(wdt_stop, 1);
goto out;
}
static void advwdt_remove(struct platform_device *dev)
{
misc_deregister(&advwdt_miscdev);
release_region(wdt_start, 1);
if (wdt_stop != wdt_start)
release_region(wdt_stop, 1);
}
static void advwdt_shutdown(struct platform_device *dev)
{
/* Turn the WDT off if we have a soft shutdown */
advwdt_disable();
}
static struct platform_driver advwdt_driver = {
.remove_new = advwdt_remove,
.shutdown = advwdt_shutdown,
.driver = {
.name = DRV_NAME,
},
};
static int __init advwdt_init(void)
{
int err;
pr_info("WDT driver for Advantech single board computer initialising\n");
advwdt_platform_device = platform_device_register_simple(DRV_NAME,
-1, NULL, 0);
if (IS_ERR(advwdt_platform_device))
return PTR_ERR(advwdt_platform_device);
err = platform_driver_probe(&advwdt_driver, advwdt_probe);
if (err)
goto unreg_platform_device;
return 0;
unreg_platform_device:
platform_device_unregister(advwdt_platform_device);
return err;
}
static void __exit advwdt_exit(void)
{
platform_device_unregister(advwdt_platform_device);
platform_driver_unregister(&advwdt_driver);
pr_info("Watchdog Module Unloaded\n");
}
module_init(advwdt_init);
module_exit(advwdt_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");