linux/drivers/watchdog/sbc_fitpc2_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

266 lines
5.3 KiB
C

/*
* Watchdog driver for SBC-FITPC2 board
*
* Author: Denis Turischev <denis@compulab.co.il>
*
* Adapted from the IXP2000 watchdog driver by Deepak Saxena.
*
* 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 " WATCHDOG: " fmt
#include <linux/module.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/dmi.h>
#include <linux/io.h>
#include <linux/uaccess.h>
static bool nowayout = WATCHDOG_NOWAYOUT;
static unsigned int margin = 60; /* (secs) Default is 1 minute */
static unsigned long wdt_status;
static DEFINE_MUTEX(wdt_lock);
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
#define COMMAND_PORT 0x4c
#define DATA_PORT 0x48
#define IFACE_ON_COMMAND 1
#define REBOOT_COMMAND 2
#define WATCHDOG_NAME "SBC-FITPC2 Watchdog"
static void wdt_send_data(unsigned char command, unsigned char data)
{
outb(data, DATA_PORT);
msleep(200);
outb(command, COMMAND_PORT);
msleep(100);
}
static void wdt_enable(void)
{
mutex_lock(&wdt_lock);
wdt_send_data(IFACE_ON_COMMAND, 1);
wdt_send_data(REBOOT_COMMAND, margin);
mutex_unlock(&wdt_lock);
}
static void wdt_disable(void)
{
mutex_lock(&wdt_lock);
wdt_send_data(IFACE_ON_COMMAND, 0);
wdt_send_data(REBOOT_COMMAND, 0);
mutex_unlock(&wdt_lock);
}
static int fitpc2_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 fitpc2_wdt_write(struct file *file, const char *data,
size_t len, loff_t *ppos)
{
size_t i;
if (!len)
return 0;
if (nowayout) {
len = 0;
goto out;
}
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);
}
out:
wdt_enable();
return len;
}
static const struct watchdog_info ident = {
.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING,
.identity = WATCHDOG_NAME,
};
static long fitpc2_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(0, (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 < 31 || time > 255) {
ret = -EINVAL;
break;
}
margin = time;
wdt_enable();
/* Fall through */
case WDIOC_GETTIMEOUT:
ret = put_user(margin, (int *)arg);
break;
}
return ret;
}
static int fitpc2_wdt_release(struct inode *inode, struct file *file)
{
if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
wdt_disable();
pr_info("Device disabled\n");
} else {
pr_warn("Device closed unexpectedly - timer will not stop\n");
wdt_enable();
}
clear_bit(WDT_IN_USE, &wdt_status);
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
return 0;
}
static const struct file_operations fitpc2_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = fitpc2_wdt_write,
.unlocked_ioctl = fitpc2_wdt_ioctl,
.open = fitpc2_wdt_open,
.release = fitpc2_wdt_release,
};
static struct miscdevice fitpc2_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &fitpc2_wdt_fops,
};
static int __init fitpc2_wdt_init(void)
{
int err;
const char *brd_name;
brd_name = dmi_get_system_info(DMI_BOARD_NAME);
if (!brd_name || !strstr(brd_name, "SBC-FITPC2"))
return -ENODEV;
pr_info("%s found\n", brd_name);
if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) {
pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT);
return -EIO;
}
if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) {
pr_err("I/O address 0x%04x already in use\n", DATA_PORT);
err = -EIO;
goto err_data_port;
}
if (margin < 31 || margin > 255) {
pr_err("margin must be in range 31 - 255 seconds, you tried to set %d\n",
margin);
err = -EINVAL;
goto err_margin;
}
err = misc_register(&fitpc2_wdt_miscdev);
if (err) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, err);
goto err_margin;
}
return 0;
err_margin:
release_region(DATA_PORT, 1);
err_data_port:
release_region(COMMAND_PORT, 1);
return err;
}
static void __exit fitpc2_wdt_exit(void)
{
misc_deregister(&fitpc2_wdt_miscdev);
release_region(DATA_PORT, 1);
release_region(COMMAND_PORT, 1);
}
module_init(fitpc2_wdt_init);
module_exit(fitpc2_wdt_exit);
MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
MODULE_DESCRIPTION("SBC-FITPC2 Watchdog");
module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
MODULE_LICENSE("GPL");