linux/drivers/watchdog/sbc_epx_c3.c
Jean Delvare 487722cf2d watchdog: Get rid of MODULE_ALIAS_MISCDEV statements
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR)
and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements.

Either the device is enumerated and the driver already has a module
alias (e.g. PCI, USB etc.) that will get the right driver loaded
automatically.

Or the device is not enumerated and loading its driver will lead to
more or less intrusive hardware poking. Such hardware poking should be
limited to a bare minimum, so the user should really decide which
drivers should be tried and in what order. Trying them all in
arbitrary order can't do any good.

On top of that, loading that many drivers at once bloats the kernel
log. Also many drivers will stay loaded afterward, bloating the output
of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets
loaded as a dependency) can't even be unloaded!

If defining char-major-10-130 is needed then it should happen in
user-space.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Jim Cromie <jim.cromie@gmail.com>
2013-11-17 19:38:13 +01:00

223 lines
5.0 KiB
C

/*
* SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX-C3
* single board computer
*
* (c) Copyright 2006 Calin A. Culianu <calin@ajvar.org>, All Rights
* Reserved.
*
* 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.
*
* based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/uaccess.h>
#include <linux/io.h>
static int epx_c3_alive;
#define WATCHDOG_TIMEOUT 1 /* 1 sec default 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) ")");
#define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */
#define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */
static void epx_c3_start(void)
{
outb(1, EPXC3_WATCHDOG_CTL_REG);
}
static void epx_c3_stop(void)
{
outb(0, EPXC3_WATCHDOG_CTL_REG);
pr_info("Stopped watchdog timer\n");
}
static void epx_c3_pet(void)
{
outb(1, EPXC3_WATCHDOG_PET_REG);
}
/*
* Allow only one person to hold it open
*/
static int epx_c3_open(struct inode *inode, struct file *file)
{
if (epx_c3_alive)
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
/* Activate timer */
epx_c3_start();
epx_c3_pet();
epx_c3_alive = 1;
pr_info("Started watchdog timer\n");
return nonseekable_open(inode, file);
}
static int epx_c3_release(struct inode *inode, struct file *file)
{
/* Shut off the timer.
* Lock it in if it's a module and we defined ...NOWAYOUT */
if (!nowayout)
epx_c3_stop(); /* Turn the WDT off */
epx_c3_alive = 0;
return 0;
}
static ssize_t epx_c3_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
/* Refresh the timer. */
if (len)
epx_c3_pet();
return len;
}
static long epx_c3_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int options, retval = -EINVAL;
int __user *argp = (void __user *)arg;
static const struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING,
.firmware_version = 0,
.identity = "Winsystems EPX-C3 H/W Watchdog",
};
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &ident, sizeof(ident)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, argp);
case WDIOC_SETOPTIONS:
if (get_user(options, argp))
return -EFAULT;
if (options & WDIOS_DISABLECARD) {
epx_c3_stop();
retval = 0;
}
if (options & WDIOS_ENABLECARD) {
epx_c3_start();
retval = 0;
}
return retval;
case WDIOC_KEEPALIVE:
epx_c3_pet();
return 0;
case WDIOC_GETTIMEOUT:
return put_user(WATCHDOG_TIMEOUT, argp);
default:
return -ENOTTY;
}
}
static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code,
void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
epx_c3_stop(); /* Turn the WDT off */
return NOTIFY_DONE;
}
static const struct file_operations epx_c3_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = epx_c3_write,
.unlocked_ioctl = epx_c3_ioctl,
.open = epx_c3_open,
.release = epx_c3_release,
};
static struct miscdevice epx_c3_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &epx_c3_fops,
};
static struct notifier_block epx_c3_notifier = {
.notifier_call = epx_c3_notify_sys,
};
static int __init watchdog_init(void)
{
int ret;
if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog"))
return -EBUSY;
ret = register_reboot_notifier(&epx_c3_notifier);
if (ret) {
pr_err("cannot register reboot notifier (err=%d)\n", ret);
goto out;
}
ret = misc_register(&epx_c3_miscdev);
if (ret) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
unregister_reboot_notifier(&epx_c3_notifier);
goto out;
}
pr_info("Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n");
return 0;
out:
release_region(EPXC3_WATCHDOG_CTL_REG, 2);
return ret;
}
static void __exit watchdog_exit(void)
{
misc_deregister(&epx_c3_miscdev);
unregister_reboot_notifier(&epx_c3_notifier);
release_region(EPXC3_WATCHDOG_CTL_REG, 2);
}
module_init(watchdog_init);
module_exit(watchdog_exit);
MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>");
MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. "
"Note that there is no way to probe for this device -- "
"so only use it if you are *sure* you are running on this specific "
"SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!");
MODULE_LICENSE("GPL");