mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
![Gustavo A. R. Silva](/assets/img/avatar_default.png)
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20200707171121.GA13472@embeddedor Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
384 lines
9.9 KiB
C
384 lines
9.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* 60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x
|
|
*
|
|
* Based on acquirewdt.c by Alan Cox.
|
|
*
|
|
* The author does NOT admit liability nor provide warranty for
|
|
* any of this software. This material is provided "AS-IS" in
|
|
* the hope that it may be useful for others.
|
|
*
|
|
* (c) Copyright 2000 Jakob Oestergaard <jakob@unthought.net>
|
|
*
|
|
* 12/4 - 2000 [Initial revision]
|
|
* 25/4 - 2000 Added /dev/watchdog support
|
|
* 09/5 - 2001 [smj@oro.net] fixed fop_write to "return 1"
|
|
* on success
|
|
* 12/4 - 2002 [rob@osinvestor.com] eliminate fop_read
|
|
* fix possible wdt_is_open race
|
|
* add CONFIG_WATCHDOG_NOWAYOUT support
|
|
* remove lock_kernel/unlock_kernel pairs
|
|
* added KERN_* to printk's
|
|
* got rid of extraneous comments
|
|
* changed watchdog_info to correctly reflect what
|
|
* the driver offers
|
|
* added WDIOC_GETSTATUS, WDIOC_GETBOOTSTATUS,
|
|
* WDIOC_SETTIMEOUT, WDIOC_GETTIMEOUT, and
|
|
* WDIOC_SETOPTIONS ioctls
|
|
* 09/8 - 2003 [wim@iguana.be] cleanup of trailing spaces
|
|
* use module_param
|
|
* made timeout (the emulated heartbeat) a
|
|
* module_param
|
|
* made the keepalive ping an internal subroutine
|
|
* made wdt_stop and wdt_start module params
|
|
* added extra printk's for startup problems
|
|
* added MODULE_AUTHOR and MODULE_DESCRIPTION info
|
|
*
|
|
* This WDT driver is different from the other Linux WDT
|
|
* drivers in the following ways:
|
|
* *) The driver will ping the watchdog by itself, because this
|
|
* particular WDT has a very short timeout (one second) and it
|
|
* would be insane to count on any userspace daemon always
|
|
* getting scheduled within that time frame.
|
|
*/
|
|
|
|
#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/jiffies.h>
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/watchdog.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/ioport.h>
|
|
#include <linux/notifier.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/init.h>
|
|
#include <linux/io.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
|
|
#define OUR_NAME "sbc60xxwdt"
|
|
#define PFX OUR_NAME ": "
|
|
|
|
/*
|
|
* You must set these - The driver cannot probe for the settings
|
|
*/
|
|
|
|
static int wdt_stop = 0x45;
|
|
module_param(wdt_stop, int, 0);
|
|
MODULE_PARM_DESC(wdt_stop, "SBC60xx WDT 'stop' io port (default 0x45)");
|
|
|
|
static int wdt_start = 0x443;
|
|
module_param(wdt_start, int, 0);
|
|
MODULE_PARM_DESC(wdt_start, "SBC60xx WDT 'start' io port (default 0x443)");
|
|
|
|
/*
|
|
* The 60xx board can use watchdog timeout values from one second
|
|
* to several minutes. The default is one second, so 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.
|
|
* If the daemon pulses us every 25 seconds, we can still afford
|
|
* a 5 second scheduling delay on the (high priority) daemon. That
|
|
* should be sufficient for a box under any load.
|
|
*/
|
|
|
|
#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
|
|
static int timeout = WATCHDOG_TIMEOUT; /* in seconds, multiplied by HZ to
|
|
get seconds to wait for a ping */
|
|
module_param(timeout, int, 0);
|
|
MODULE_PARM_DESC(timeout,
|
|
"Watchdog timeout in seconds. (1<=timeout<=3600, 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) ")");
|
|
|
|
static void wdt_timer_ping(struct timer_list *);
|
|
static DEFINE_TIMER(timer, wdt_timer_ping);
|
|
static unsigned long next_heartbeat;
|
|
static unsigned long wdt_is_open;
|
|
static char wdt_expect_close;
|
|
|
|
/*
|
|
* Whack the dog
|
|
*/
|
|
|
|
static void wdt_timer_ping(struct timer_list *unused)
|
|
{
|
|
/* If we got a heartbeat pulse within the WDT_US_INTERVAL
|
|
* we agree to ping the WDT
|
|
*/
|
|
if (time_before(jiffies, next_heartbeat)) {
|
|
/* Ping the WDT by reading from wdt_start */
|
|
inb_p(wdt_start);
|
|
/* Re-set the timer interval */
|
|
mod_timer(&timer, jiffies + WDT_INTERVAL);
|
|
} else
|
|
pr_warn("Heartbeat lost! Will not ping the watchdog\n");
|
|
}
|
|
|
|
/*
|
|
* Utility routines
|
|
*/
|
|
|
|
static void wdt_startup(void)
|
|
{
|
|
next_heartbeat = jiffies + (timeout * HZ);
|
|
|
|
/* Start the timer */
|
|
mod_timer(&timer, jiffies + WDT_INTERVAL);
|
|
pr_info("Watchdog timer is now enabled\n");
|
|
}
|
|
|
|
static void wdt_turnoff(void)
|
|
{
|
|
/* Stop the timer */
|
|
del_timer(&timer);
|
|
inb_p(wdt_stop);
|
|
pr_info("Watchdog timer is now disabled...\n");
|
|
}
|
|
|
|
static void wdt_keepalive(void)
|
|
{
|
|
/* user land ping */
|
|
next_heartbeat = jiffies + (timeout * HZ);
|
|
}
|
|
|
|
/*
|
|
* /dev/watchdog handling
|
|
*/
|
|
|
|
static ssize_t fop_write(struct file *file, const char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
/* See if we got the magic character 'V' and reload the timer */
|
|
if (count) {
|
|
if (!nowayout) {
|
|
size_t ofs;
|
|
|
|
/* note: just in case someone wrote the
|
|
magic character five months ago... */
|
|
wdt_expect_close = 0;
|
|
|
|
/* scan to see whether or not we got the
|
|
magic character */
|
|
for (ofs = 0; ofs != count; ofs++) {
|
|
char c;
|
|
if (get_user(c, buf + ofs))
|
|
return -EFAULT;
|
|
if (c == 'V')
|
|
wdt_expect_close = 42;
|
|
}
|
|
}
|
|
|
|
/* Well, anyhow someone wrote to us, we should
|
|
return that favour */
|
|
wdt_keepalive();
|
|
}
|
|
return count;
|
|
}
|
|
|
|
static int fop_open(struct inode *inode, struct file *file)
|
|
{
|
|
/* Just in case we're already talking to someone... */
|
|
if (test_and_set_bit(0, &wdt_is_open))
|
|
return -EBUSY;
|
|
|
|
if (nowayout)
|
|
__module_get(THIS_MODULE);
|
|
|
|
/* Good, fire up the show */
|
|
wdt_startup();
|
|
return stream_open(inode, file);
|
|
}
|
|
|
|
static int fop_close(struct inode *inode, struct file *file)
|
|
{
|
|
if (wdt_expect_close == 42)
|
|
wdt_turnoff();
|
|
else {
|
|
del_timer(&timer);
|
|
pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
|
|
}
|
|
clear_bit(0, &wdt_is_open);
|
|
wdt_expect_close = 0;
|
|
return 0;
|
|
}
|
|
|
|
static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
|
|
{
|
|
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 = "SBC60xx",
|
|
};
|
|
|
|
switch (cmd) {
|
|
case WDIOC_GETSUPPORT:
|
|
return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
|
|
case WDIOC_GETSTATUS:
|
|
case WDIOC_GETBOOTSTATUS:
|
|
return put_user(0, p);
|
|
case WDIOC_SETOPTIONS:
|
|
{
|
|
int new_options, retval = -EINVAL;
|
|
if (get_user(new_options, p))
|
|
return -EFAULT;
|
|
if (new_options & WDIOS_DISABLECARD) {
|
|
wdt_turnoff();
|
|
retval = 0;
|
|
}
|
|
if (new_options & WDIOS_ENABLECARD) {
|
|
wdt_startup();
|
|
retval = 0;
|
|
}
|
|
return retval;
|
|
}
|
|
case WDIOC_KEEPALIVE:
|
|
wdt_keepalive();
|
|
return 0;
|
|
case WDIOC_SETTIMEOUT:
|
|
{
|
|
int new_timeout;
|
|
if (get_user(new_timeout, p))
|
|
return -EFAULT;
|
|
/* arbitrary upper limit */
|
|
if (new_timeout < 1 || new_timeout > 3600)
|
|
return -EINVAL;
|
|
|
|
timeout = new_timeout;
|
|
wdt_keepalive();
|
|
}
|
|
fallthrough;
|
|
case WDIOC_GETTIMEOUT:
|
|
return put_user(timeout, p);
|
|
default:
|
|
return -ENOTTY;
|
|
}
|
|
}
|
|
|
|
static const struct file_operations wdt_fops = {
|
|
.owner = THIS_MODULE,
|
|
.llseek = no_llseek,
|
|
.write = fop_write,
|
|
.open = fop_open,
|
|
.release = fop_close,
|
|
.unlocked_ioctl = fop_ioctl,
|
|
.compat_ioctl = compat_ptr_ioctl,
|
|
};
|
|
|
|
static struct miscdevice wdt_miscdev = {
|
|
.minor = WATCHDOG_MINOR,
|
|
.name = "watchdog",
|
|
.fops = &wdt_fops,
|
|
};
|
|
|
|
/*
|
|
* Notifier for system down
|
|
*/
|
|
|
|
static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
|
|
void *unused)
|
|
{
|
|
if (code == SYS_DOWN || code == SYS_HALT)
|
|
wdt_turnoff();
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
/*
|
|
* The WDT needs to learn about soft shutdowns in order to
|
|
* turn the timebomb registers off.
|
|
*/
|
|
|
|
static struct notifier_block wdt_notifier = {
|
|
.notifier_call = wdt_notify_sys,
|
|
};
|
|
|
|
static void __exit sbc60xxwdt_unload(void)
|
|
{
|
|
wdt_turnoff();
|
|
|
|
/* Deregister */
|
|
misc_deregister(&wdt_miscdev);
|
|
|
|
unregister_reboot_notifier(&wdt_notifier);
|
|
if ((wdt_stop != 0x45) && (wdt_stop != wdt_start))
|
|
release_region(wdt_stop, 1);
|
|
release_region(wdt_start, 1);
|
|
}
|
|
|
|
static int __init sbc60xxwdt_init(void)
|
|
{
|
|
int rc = -EBUSY;
|
|
|
|
if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */
|
|
timeout = WATCHDOG_TIMEOUT;
|
|
pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
|
|
timeout);
|
|
}
|
|
|
|
if (!request_region(wdt_start, 1, "SBC 60XX WDT")) {
|
|
pr_err("I/O address 0x%04x already in use\n", wdt_start);
|
|
rc = -EIO;
|
|
goto err_out;
|
|
}
|
|
|
|
/* We cannot reserve 0x45 - the kernel already has! */
|
|
if (wdt_stop != 0x45 && wdt_stop != wdt_start) {
|
|
if (!request_region(wdt_stop, 1, "SBC 60XX WDT")) {
|
|
pr_err("I/O address 0x%04x already in use\n", wdt_stop);
|
|
rc = -EIO;
|
|
goto err_out_region1;
|
|
}
|
|
}
|
|
|
|
rc = register_reboot_notifier(&wdt_notifier);
|
|
if (rc) {
|
|
pr_err("cannot register reboot notifier (err=%d)\n", rc);
|
|
goto err_out_region2;
|
|
}
|
|
|
|
rc = misc_register(&wdt_miscdev);
|
|
if (rc) {
|
|
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
|
|
wdt_miscdev.minor, rc);
|
|
goto err_out_reboot;
|
|
}
|
|
pr_info("WDT driver for 60XX single board computer initialised. timeout=%d sec (nowayout=%d)\n",
|
|
timeout, nowayout);
|
|
|
|
return 0;
|
|
|
|
err_out_reboot:
|
|
unregister_reboot_notifier(&wdt_notifier);
|
|
err_out_region2:
|
|
if (wdt_stop != 0x45 && wdt_stop != wdt_start)
|
|
release_region(wdt_stop, 1);
|
|
err_out_region1:
|
|
release_region(wdt_start, 1);
|
|
err_out:
|
|
return rc;
|
|
}
|
|
|
|
module_init(sbc60xxwdt_init);
|
|
module_exit(sbc60xxwdt_unload);
|
|
|
|
MODULE_AUTHOR("Jakob Oestergaard <jakob@unthought.net>");
|
|
MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver");
|
|
MODULE_LICENSE("GPL");
|