linux/drivers/watchdog/ixp4xx_wdt.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

211 lines
4.6 KiB
C

/*
* drivers/char/watchdog/ixp4xx_wdt.c
*
* Watchdog driver for Intel IXP4xx network processors
*
* Author: Deepak Saxena <dsaxena@plexity.net>
*
* Copyright 2004 (c) MontaVista, Software, Inc.
* Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#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/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <mach/hardware.h>
static bool nowayout = WATCHDOG_NOWAYOUT;
static int heartbeat = 60; /* (secs) Default is 1 minute */
static unsigned long wdt_status;
static unsigned long boot_status;
static DEFINE_SPINLOCK(wdt_lock);
#define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
static void wdt_enable(void)
{
spin_lock(&wdt_lock);
*IXP4XX_OSWK = IXP4XX_WDT_KEY;
*IXP4XX_OSWE = 0;
*IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
*IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
*IXP4XX_OSWK = 0;
spin_unlock(&wdt_lock);
}
static void wdt_disable(void)
{
spin_lock(&wdt_lock);
*IXP4XX_OSWK = IXP4XX_WDT_KEY;
*IXP4XX_OSWE = 0;
*IXP4XX_OSWK = 0;
spin_unlock(&wdt_lock);
}
static int ixp4xx_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(WDT_IN_USE, &wdt_status))
return -EBUSY;
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
wdt_enable();
return nonseekable_open(inode, file);
}
static ssize_t
ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
{
if (len) {
if (!nowayout) {
size_t i;
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
set_bit(WDT_OK_TO_CLOSE, &wdt_status);
}
}
wdt_enable();
}
return len;
}
static const struct watchdog_info ident = {
.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "IXP4xx Watchdog",
};
static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int ret = -ENOTTY;
int time;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user((struct watchdog_info *)arg, &ident,
sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(boot_status, (int *)arg);
break;
case WDIOC_KEEPALIVE:
wdt_enable();
ret = 0;
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, (int *)arg);
if (ret)
break;
if (time <= 0 || time > 60) {
ret = -EINVAL;
break;
}
heartbeat = time;
wdt_enable();
/* Fall through */
case WDIOC_GETTIMEOUT:
ret = put_user(heartbeat, (int *)arg);
break;
}
return ret;
}
static int ixp4xx_wdt_release(struct inode *inode, struct file *file)
{
if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
wdt_disable();
else
pr_crit("Device closed unexpectedly - timer will not stop\n");
clear_bit(WDT_IN_USE, &wdt_status);
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
return 0;
}
static const struct file_operations ixp4xx_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = ixp4xx_wdt_write,
.unlocked_ioctl = ixp4xx_wdt_ioctl,
.open = ixp4xx_wdt_open,
.release = ixp4xx_wdt_release,
};
static struct miscdevice ixp4xx_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &ixp4xx_wdt_fops,
};
static int __init ixp4xx_wdt_init(void)
{
int ret;
if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
pr_err("Rev. A0 IXP42x CPU detected - watchdog disabled\n");
return -ENODEV;
}
boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
WDIOF_CARDRESET : 0;
ret = misc_register(&ixp4xx_wdt_miscdev);
if (ret == 0)
pr_info("timer heartbeat %d sec\n", heartbeat);
return ret;
}
static void __exit ixp4xx_wdt_exit(void)
{
misc_deregister(&ixp4xx_wdt_miscdev);
}
module_init(ixp4xx_wdt_init);
module_exit(ixp4xx_wdt_exit);
MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
MODULE_LICENSE("GPL");