linux/drivers/watchdog/iop_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

262 lines
5.9 KiB
C

/*
* drivers/char/watchdog/iop_wdt.c
*
* WDT driver for Intel I/O Processors
* Copyright (C) 2005, Intel Corporation.
*
* Based on ixp4xx driver, Copyright 2004 (c) MontaVista, Software, Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place - Suite 330, Boston, MA 02111-1307 USA.
*
* Curt E Bruns <curt.e.bruns@intel.com>
* Peter Milne <peter.milne@d-tacq.com>
* Dan Williams <dan.j.williams@intel.com>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <mach/hardware.h>
static bool nowayout = WATCHDOG_NOWAYOUT;
static unsigned long wdt_status;
static unsigned long boot_status;
static DEFINE_SPINLOCK(wdt_lock);
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
#define WDT_ENABLED 2
static unsigned long iop_watchdog_timeout(void)
{
return (0xffffffffUL / get_iop_tick_rate());
}
/**
* wdt_supports_disable - determine if we are accessing a iop13xx watchdog
* or iop3xx by whether it has a disable command
*/
static int wdt_supports_disable(void)
{
int can_disable;
if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM)
can_disable = 1;
else
can_disable = 0;
return can_disable;
}
static void wdt_enable(void)
{
/* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF
* Takes approx. 10.7s to timeout
*/
spin_lock(&wdt_lock);
write_wdtcr(IOP_WDTCR_EN_ARM);
write_wdtcr(IOP_WDTCR_EN);
spin_unlock(&wdt_lock);
}
/* returns 0 if the timer was successfully disabled */
static int wdt_disable(void)
{
/* Stop Counting */
if (wdt_supports_disable()) {
spin_lock(&wdt_lock);
write_wdtcr(IOP_WDTCR_DIS_ARM);
write_wdtcr(IOP_WDTCR_DIS);
clear_bit(WDT_ENABLED, &wdt_status);
spin_unlock(&wdt_lock);
pr_info("Disabled\n");
return 0;
} else
return 1;
}
static int iop_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();
set_bit(WDT_ENABLED, &wdt_status);
return nonseekable_open(inode, file);
}
static ssize_t iop_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_KEEPALIVEPING,
.identity = "iop watchdog",
};
static long iop_wdt_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
int options;
int ret = -ENOTTY;
int __user *argp = (int __user *)arg;
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &ident, sizeof(ident)))
ret = -EFAULT;
else
ret = 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, argp);
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(boot_status, argp);
break;
case WDIOC_SETOPTIONS:
if (get_user(options, (int *)arg))
return -EFAULT;
if (options & WDIOS_DISABLECARD) {
if (!nowayout) {
if (wdt_disable() == 0) {
set_bit(WDT_OK_TO_CLOSE, &wdt_status);
ret = 0;
} else
ret = -ENXIO;
} else
ret = 0;
}
if (options & WDIOS_ENABLECARD) {
wdt_enable();
ret = 0;
}
break;
case WDIOC_KEEPALIVE:
wdt_enable();
ret = 0;
break;
case WDIOC_GETTIMEOUT:
ret = put_user(iop_watchdog_timeout(), argp);
break;
}
return ret;
}
static int iop_wdt_release(struct inode *inode, struct file *file)
{
int state = 1;
if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
if (test_bit(WDT_ENABLED, &wdt_status))
state = wdt_disable();
/* if the timer is not disabled reload and notify that we are still
* going down
*/
if (state != 0) {
wdt_enable();
pr_crit("Device closed unexpectedly - reset in %lu seconds\n",
iop_watchdog_timeout());
}
clear_bit(WDT_IN_USE, &wdt_status);
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
return 0;
}
static const struct file_operations iop_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = iop_wdt_write,
.unlocked_ioctl = iop_wdt_ioctl,
.open = iop_wdt_open,
.release = iop_wdt_release,
};
static struct miscdevice iop_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &iop_wdt_fops,
};
static int __init iop_wdt_init(void)
{
int ret;
/* check if the reset was caused by the watchdog timer */
boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0;
/* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset
* NOTE: An IB Reset will Reset both cores in the IOP342
*/
write_wdtsr(IOP13XX_WDTCR_IB_RESET);
/* Register after we have the device set up so we cannot race
with an open */
ret = misc_register(&iop_wdt_miscdev);
if (ret == 0)
pr_info("timeout %lu sec\n", iop_watchdog_timeout());
return ret;
}
static void __exit iop_wdt_exit(void)
{
misc_deregister(&iop_wdt_miscdev);
}
module_init(iop_wdt_init);
module_exit(iop_wdt_exit);
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>");
MODULE_DESCRIPTION("iop watchdog timer driver");
MODULE_LICENSE("GPL");