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linux/drivers/watchdog/ib700wdt.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

387 lines
8.4 KiB
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/*
* IB700 Single Board Computer WDT driver
*
* (c) Copyright 2001 Charles Howes <chowes@vsol.net>
*
* Based on advantechwdt.c which is based on acquirewdt.c which
* is based on wdt.c.
*
* (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.
*
* 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.
*
* 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
* Added timeout module option to override default
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/ioport.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/uaccess.h>
static struct platform_device *ibwdt_platform_device;
static unsigned long ibwdt_is_open;
static DEFINE_SPINLOCK(ibwdt_lock);
static char expect_close;
/* Module information */
#define DRV_NAME "ib700wdt"
/*
*
* Watchdog Timer Configuration
*
* The function of the watchdog timer is to reset the system
* automatically and is defined at I/O port 0443H. To enable the
* watchdog timer and allow the system to reset, write I/O port 0443H.
* To disable the timer, write I/O port 0441H for the system to stop the
* watchdog function. The timer has a tolerance of 20% for its
* intervals.
*
* The following describes how the timer should be programmed.
*
* Enabling Watchdog:
* MOV AX,000FH (Choose the values from 0 to F)
* MOV DX,0443H
* OUT DX,AX
*
* Disabling Watchdog:
* MOV AX,000FH (Any value is fine.)
* MOV DX,0441H
* OUT DX,AX
*
* Watchdog timer control table:
* Level Value Time/sec | Level Value Time/sec
* 1 F 0 | 9 7 16
* 2 E 2 | 10 6 18
* 3 D 4 | 11 5 20
* 4 C 6 | 12 4 22
* 5 B 8 | 13 3 24
* 6 A 10 | 14 2 26
* 7 9 12 | 15 1 28
* 8 8 14 | 16 0 30
*
*/
#define WDT_STOP 0x441
#define WDT_START 0x443
/* Default timeout */
#define WATCHDOG_TIMEOUT 30 /* 30 seconds +/- 20% */
static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. 0<= timeout <=30, 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 ibwdt_ping(void)
{
int wd_margin = 15 - ((timeout + 1) / 2);
spin_lock(&ibwdt_lock);
/* Write a watchdog value */
outb_p(wd_margin, WDT_START);
spin_unlock(&ibwdt_lock);
}
static void ibwdt_disable(void)
{
spin_lock(&ibwdt_lock);
outb_p(0, WDT_STOP);
spin_unlock(&ibwdt_lock);
}
static int ibwdt_set_heartbeat(int t)
{
if (t < 0 || t > 30)
return -EINVAL;
timeout = t;
return 0;
}
/*
* /dev/watchdog handling
*/
static ssize_t ibwdt_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
if (count) {
if (!nowayout) {
size_t i;
/* In case it was set long ago */
expect_close = 0;
for (i = 0; i != count; i++) {
char c;
if (get_user(c, buf + i))
return -EFAULT;
if (c == 'V')
expect_close = 42;
}
}
ibwdt_ping();
}
return count;
}
static long ibwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int new_margin;
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 = "IB700 WDT",
};
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) {
ibwdt_disable();
retval = 0;
}
if (options & WDIOS_ENABLECARD) {
ibwdt_ping();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
ibwdt_ping();
break;
case WDIOC_SETTIMEOUT:
if (get_user(new_margin, p))
return -EFAULT;
if (ibwdt_set_heartbeat(new_margin))
return -EINVAL;
ibwdt_ping();
/* Fall */
case WDIOC_GETTIMEOUT:
return put_user(timeout, p);
default:
return -ENOTTY;
}
return 0;
}
static int ibwdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &ibwdt_is_open))
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
/* Activate */
ibwdt_ping();
return nonseekable_open(inode, file);
}
static int ibwdt_close(struct inode *inode, struct file *file)
{
if (expect_close == 42) {
ibwdt_disable();
} else {
pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
ibwdt_ping();
}
clear_bit(0, &ibwdt_is_open);
expect_close = 0;
return 0;
}
/*
* Kernel Interfaces
*/
static const struct file_operations ibwdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = ibwdt_write,
.unlocked_ioctl = ibwdt_ioctl,
.open = ibwdt_open,
.release = ibwdt_close,
};
static struct miscdevice ibwdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &ibwdt_fops,
};
/*
* Init & exit routines
*/
static int ibwdt_probe(struct platform_device *dev)
{
int res;
#if WDT_START != WDT_STOP
if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
pr_err("STOP method I/O %X is not available\n", WDT_STOP);
res = -EIO;
goto out_nostopreg;
}
#endif
if (!request_region(WDT_START, 1, "IB700 WDT")) {
pr_err("START method I/O %X is not available\n", WDT_START);
res = -EIO;
goto out_nostartreg;
}
/* Check that the heartbeat value is within it's range ;
* if not reset to the default */
if (ibwdt_set_heartbeat(timeout)) {
ibwdt_set_heartbeat(WATCHDOG_TIMEOUT);
pr_info("timeout value must be 0<=x<=30, using %d\n", timeout);
}
res = misc_register(&ibwdt_miscdev);
if (res) {
pr_err("failed to register misc device\n");
goto out_nomisc;
}
return 0;
out_nomisc:
release_region(WDT_START, 1);
out_nostartreg:
#if WDT_START != WDT_STOP
release_region(WDT_STOP, 1);
#endif
out_nostopreg:
return res;
}
static int ibwdt_remove(struct platform_device *dev)
{
misc_deregister(&ibwdt_miscdev);
release_region(WDT_START, 1);
#if WDT_START != WDT_STOP
release_region(WDT_STOP, 1);
#endif
return 0;
}
static void ibwdt_shutdown(struct platform_device *dev)
{
/* Turn the WDT off if we have a soft shutdown */
ibwdt_disable();
}
static struct platform_driver ibwdt_driver = {
.probe = ibwdt_probe,
.remove = ibwdt_remove,
.shutdown = ibwdt_shutdown,
.driver = {
.owner = THIS_MODULE,
.name = DRV_NAME,
},
};
static int __init ibwdt_init(void)
{
int err;
pr_info("WDT driver for IB700 single board computer initialising\n");
err = platform_driver_register(&ibwdt_driver);
if (err)
return err;
ibwdt_platform_device = platform_device_register_simple(DRV_NAME,
-1, NULL, 0);
if (IS_ERR(ibwdt_platform_device)) {
err = PTR_ERR(ibwdt_platform_device);
goto unreg_platform_driver;
}
return 0;
unreg_platform_driver:
platform_driver_unregister(&ibwdt_driver);
return err;
}
static void __exit ibwdt_exit(void)
{
platform_device_unregister(ibwdt_platform_device);
platform_driver_unregister(&ibwdt_driver);
pr_info("Watchdog Module Unloaded\n");
}
module_init(ibwdt_init);
module_exit(ibwdt_exit);
MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
MODULE_DESCRIPTION("IB700 SBC watchdog driver");
MODULE_LICENSE("GPL");
/* end of ib700wdt.c */
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