第一部分: WDT驱动原理
WDT在内核中通常都实现为misc驱动。
WDT介绍
一个Watchdog Timer(WDT)是一个在软件出错的时候可以复位计算机系统的硬件电路。
通常一个用户空间守护进程会在正常的时间间隔内通过/dev/watchdog特殊设备文件来通知内核的watchdog驱动,用户空间仍然正常。当这样的一个通知发生时,驱动通常会告诉硬件watchdog一切正常,然后watchdog应该再等待一段时间来复位系统。如果用户空间出问题(RAM错误,内核bug等),则通知将会停止,然后硬件watchdog将在超时后复位系统。
Linux的watchdog API是一个相当特别的东西,不同的驱动实现是不同的,而且有时部分是不兼容的。这个文档正是要尝试着去说明已经出现的用法,并且使以后的驱动作者把它作为一份参考。
最简单的 API:
所有的设备驱动都支持的基本的操作模式,一旦/dev/watchdog被打开,则watchdog激活,并且除非喂狗,否则将在一段时间之后重启,这个时间被称为timeout或margin。最简单的喂狗方法就是写一些数据到设备。一个非常简单的watchdog守护进程看起来就像这个文件这样:
Documentation/watchdog/src/watchdog-simple.c
- #include <stdio.h>
-
#include <stdlib.h>
-
#include <unistd.h>
-
#include <fcntl.h>
-
-
int main(void)
-
{
-
int fd = open("/dev/watchdog", O_WRONLY);
-
int ret = 0;
-
if (fd == -1) {
-
perror("watchdog");
-
exit(EXIT_FAILURE);
-
}
-
while (1) {
-
ret = write(fd, "\0", 1);
-
if (ret != 1) {
-
ret = -1;
-
break;
-
}
-
ret = fsync(fd);
-
if (ret)
-
break;
-
sleep(10);
-
}
-
close(fd);
-
return ret;
-
}
一个高级一些的驱动在喂狗之前,可能还会做一些其他的事情,比如说检查HTTP服务器是否依然可以相应。
当设备关闭的时候,除非支持"Magic Close"特性。否则watchdog被关闭。这并不总是一个好主意,比如watchdog守护进程出现了bug并且崩溃了,则系统将不会重启。因此,某些驱动支持"Disable watchdog shutdown on close", CONFIG_WATCHDOG_NOWAYOUT配置选项。当编译内核的时候这个选项被设置为Y,则一旦watchdog被启动,则将没有办法能够停止。这样,则当watchdog守护进程崩溃的时候,系统仍将在超时后重启。Watchdog设备常常也支持nowayout模块参数,这样这个选项就可以在运行时进行控制。
Magic Close 特性:
如果一个驱动支持"Magic Close",则除非在关闭文件前,魔幻字符'V'被发送到/dev/watchdog,驱动将不停止watchdog。如果用户空间守护进程在关闭文件前没有发送这个字符,则驱动认为用户空间崩溃,并在关闭watchdog前停止喂狗。
这样的话,如果没有在一定的时间内重新打开watchdog,则将导致一个重启。
ioctl API:
所有标准的驱动也应该支持一个ioctl API。
喂狗使用一个ioctl:
所有的驱动都有一个ioctl接口支持至少一个ioctl命令,KEEPALIVE。这个 ioctl 做的事和一个写watchdog设备完全一样,所以,上面程序的主循环可以替换为:
- while (1) {
-
-
ioctl(fd, WDIOC_KEEPALIVE, 0);
-
-
sleep(10);
-
-
}
ioctl的参数被忽略。
设置和获得超时值:
对于某些驱动来说,在上层使用SETTIMEOUT ioctl命令改变watchdog的超时值是可能的,那些驱动在他们的选项与中有WDIOF_SETTIMEOUT标志。参数是一个代表以秒为单位的超时值,驱动将在同一个变量中返回实际使用的超时值,这个超时值可能由于硬件的限制,而不同于所请求的超时值
int timeout = 45;
ioctl(fd, WDIOC_SETTIMEOUT, &timeout);
printf("The timeout was set to %d seconds\n", timeout);
如果设备的超时值的粒度只能到分钟,则这个例子可能实际打印"The timeout was set to 60 seconds"。
自从Linux 2.4.18内核,通过GETTIMEOUT ioctl命令查询当前超时值也是可能的:
ioctl(fd, WDIOC_GETTIMEOUT, &timeout);
printf("The timeout was is %d seconds\n", timeout);
预处理:
Pretimeouts:
一些watchdog定时器,可以被设置为,在他们实际复位系统前,有一个触发。这可能通过一个NMI,中断,或其他机制。这将允许在它复位系统前Linux去记录一些有用的信息(比如panic信息和内核转储)。
pretimeout = 10;
ioctl(fd, WDIOC_SETPRETIMEOUT, &pretimeout);
注意,预超时值应该是一个相对于超时值提前的秒数。而不是直到预超时的秒数。
比如,如果你设置超时值为60秒,预超时值为10秒,那么预超时将在50秒后到达。设置为0则是禁用它。预超时还有一个get功能:
ioctl(fd, WDIOC_GETPRETIMEOUT, &timeout);
printf("The pretimeout was is %d seconds\n", timeout);
不是所有的watchdog驱动都支持一个预超时的。
获得重启前的秒数
一些watchdog驱动有一个报告在重启前的剩余时间的功能。WDIOC_GETTIMELEFT就是返回重启前的秒数的ioctl命令。
ioctl(fd, WDIOC_GETTIMELEFT, &timeleft);
printf("The timeout was is %d seconds\n", timeleft);
环境监视:
Environmental monitoring:
所有的watchdog驱动都被要求返回更多关于系统的信息,有些返回温度,风扇和功率水平监测,依稀可以告诉你上一次重启系统的原因。GETSUPPORT ioctl可以用来查询设备可以做什么:
struct watchdog_info ident;
ioctl(fd, WDIOC_GETSUPPORT, &ident);
ident结构中返回的字段是:
identity 一个标识watchdog驱动的字符串
firmware_version 如果可用的话,就是卡的固件版本
options 一个描述设备支持什么的标志
options字段可以有下面的位集,和描述GET_STATUS 和 GET_BOOT_STATUS ioctls可以返回什么种类的信息。
第二部分: WDT驱动源码
驱动架构比较简单,由于kernel启动时,定义并加入了watchdog的platform_device,所以驱动定义并注册watchdog 的platform_driver- /* linux/drivers/char/watchdog/s3c2410_wdt.c
-
*
-
* Copyright (c) 2004 Simtec Electronics
-
* Ben Dooks <ben@simtec.co.uk>
-
*
-
* S3C2410 Watchdog Timer Support
-
*
-
* Based on, softdog.c by Alan Cox,
-
* (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>
-
*
-
* 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.
-
*
-
* This program is distributed in the hope that 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
-
*/
-
-
#include <linux/module.h>
-
#include <linux/moduleparam.h>
-
#include <linux/types.h>
-
#include <linux/timer.h>
-
#include <linux/miscdevice.h>
-
#include <linux/watchdog.h>
-
#include <linux/fs.h>
-
#include <linux/init.h>
-
#include <linux/platform_device.h>
-
#include <linux/interrupt.h>
-
#include <linux/clk.h>
-
#include <linux/uaccess.h>
-
#include <linux/io.h>
-
-
#include <mach/map.h>
-
-
#undef S3C_VA_WATCHDOG
-
#define S3C_VA_WATCHDOG (0)
-
-
#include <plat/regs-watchdog.h>
-
-
#define PFX "s3c2410-wdt: "
-
-
#define CONFIG_S3C2410_WATCHDOG_ATBOOT (0)
-
#define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (15)
-
-
static int nowayout = WATCHDOG_NOWAYOUT;
-
static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
-
static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT;
-
static int soft_noboot;
-
static int debug;
-
-
module_param(tmr_margin, int, 0);
-
module_param(tmr_atboot, int, 0);
-
module_param(nowayout, int, 0);
-
module_param(soft_noboot, int, 0);
-
module_param(debug, int, 0);
-
-
MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default="
-
__MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
-
MODULE_PARM_DESC(tmr_atboot,
-
"Watchdog is started at boot time if set to 1, default="
-
__MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
-
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
-
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
-
MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, "
-
"0 to reboot (default depends on ONLY_TESTING)");
-
MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");
-
-
static unsigned long open_lock;
-
static struct device *wdt_dev; /* platform device attached to */
-
static struct resource *wdt_mem;
-
static struct resource *wdt_irq;
-
static struct clk *wdt_clock;
-
static void __iomem *wdt_base;
-
static unsigned int wdt_count;
-
static char expect_close;
-
static DEFINE_SPINLOCK(wdt_lock);
-
-
/* watchdog control routines */
-
-
#define DBG(msg...) do { \
-
if (debug) \
-
printk(KERN_INFO msg); \
-
} while (0)
-
/* functions */
-
-
static void s3c2410wdt_keepalive(void)
-
{
-
spin_lock(&wdt_lock);
-
writel(wdt_count, wdt_base + S3C2410_WTCNT);
-
spin_unlock(&wdt_lock);
-
}
-
-
static void __s3c2410wdt_stop(void)
-
{
-
unsigned long wtcon;
-
-
wtcon = readl(wdt_base + S3C2410_WTCON);
-
wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
-
writel(wtcon, wdt_base + S3C2410_WTCON);
-
}
-
-
static void s3c2410wdt_stop(void)
-
{
-
spin_lock(&wdt_lock);
-
__s3c2410wdt_stop();
-
spin_unlock(&wdt_lock);
-
}
-
-
static void s3c2410wdt_start(void)
-
{
-
unsigned long wtcon;
-
-
spin_lock(&wdt_lock);
-
-
__s3c2410wdt_stop();
-
-
wtcon = readl(wdt_base + S3C2410_WTCON);
-
wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
-
-
if (soft_noboot) {
-
wtcon |= S3C2410_WTCON_INTEN;
-
wtcon &= ~S3C2410_WTCON_RSTEN;
-
} else {
-
wtcon &= ~S3C2410_WTCON_INTEN;
-
wtcon |= S3C2410_WTCON_RSTEN;
-
}
-
-
DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n",
-
__func__, wdt_count, wtcon);
-
-
writel(wdt_count, wdt_base + S3C2410_WTDAT);
-
writel(wdt_count, wdt_base + S3C2410_WTCNT);
-
writel(wtcon, wdt_base + S3C2410_WTCON);
-
spin_unlock(&wdt_lock);
-
}
-
-
static int s3c2410wdt_set_heartbeat(int timeout)
-
{
-
unsigned int freq = clk_get_rate(wdt_clock);
-
unsigned int count;
-
unsigned int divisor = 1;
-
unsigned long wtcon;
-
if (timeout < 1)
-
return -EINVAL;
-
-
freq /= 128;
-
count = timeout * freq;
-
-
DBG("%s: count=%d, timeout=%d, freq=%d\n",
-
__func__, count, timeout, freq);
-
-
/* if the count is bigger than the watchdog register,
-
then work out what we need to do (and if) we can
-
actually make this value
-
*/
-
-
if (count >= 0x10000) {
-
for (divisor = 1; divisor <= 0x100; divisor++) {
-
if ((count / divisor) < 0x10000)
-
break;
-
}
-
-
if ((count / divisor) >= 0x10000) {
-
dev_err(wdt_dev, "timeout %d too big\n", timeout);
-
return -EINVAL;
-
}
-
}
-
-
tmr_margin = timeout;
-
-
DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n",
-
__func__, timeout, divisor, count, count/divisor);
-
-
count /= divisor;
-
wdt_count = count;
-
-
/* update the pre-scaler */
-
wtcon = readl(wdt_base + S3C2410_WTCON);
-
wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;
-
wtcon |= S3C2410_WTCON_PRESCALE(divisor-1);
-
-
writel(count, wdt_base + S3C2410_WTDAT);
-
writel(wtcon, wdt_base + S3C2410_WTCON);
-
-
return 0;
-
}
-
-
/*
-
* /dev/watchdog handling
-
*/
-
-
static int s3c2410wdt_open(struct inode *inode, struct file *file)
-
{
-
if (test_and_set_bit(0, &open_lock))
-
return -EBUSY;
-
-
if (nowayout)
-
__module_get(THIS_MODULE);
-
-
expect_close = 0;
-
-
/* start the timer */
-
s3c2410wdt_start();
-
return nonseekable_open(inode, file);
-
}
-
-
static int s3c2410wdt_release(struct inode *inode, struct file *file)
-
{
-
/*
-
* Shut off the timer.
-
* Lock it in if it's a module and we set nowayout
-
*/
-
-
if (expect_close == 42)
-
s3c2410wdt_stop();
-
else {
-
dev_err(wdt_dev, "Unexpected close, not stopping watchdog\n");
-
s3c2410wdt_keepalive();
-
}
-
expect_close = 0;
-
clear_bit(0, &open_lock);
-
return 0;
-
}
-
-
static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
-
size_t len, loff_t *ppos)
-
{
-
/*
-
* Refresh the timer.
-
*/
-
if (len) {
-
if (!nowayout) {
-
size_t i;
-
-
/* In case it was set long ago */
-
expect_close = 0;
-
-
for (i = 0; i != len; i++) {
-
char c;
-
-
if (get_user(c, data + i))
-
return -EFAULT;
-
if (c == 'V')
-
expect_close = 42;
-
}
-
}
-
s3c2410wdt_keepalive();
-
}
-
return len;
-
}
-
-
#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
-
-
static const struct watchdog_info s3c2410_wdt_ident = {
-
.options = OPTIONS,
-
.firmware_version = 0,
-
.identity = "S3C2410 Watchdog",
-
};
-
-
-
static long s3c2410wdt_ioctl(struct file *file, unsigned int cmd,
-
unsigned long arg)
-
{
-
void __user *argp = (void __user *)arg;
-
int __user *p = argp;
-
int new_margin;
-
-
switch (cmd) {
-
case WDIOC_GETSUPPORT:
-
return copy_to_user(argp, &s3c2410_wdt_ident,
-
sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
-
case WDIOC_GETSTATUS:
-
case WDIOC_GETBOOTSTATUS:
-
return put_user(0, p);
-
case WDIOC_KEEPALIVE:
-
s3c2410wdt_keepalive();
-
return 0;
-
case WDIOC_SETTIMEOUT:
-
if (get_user(new_margin, p))
-
return -EFAULT;
-
if (s3c2410wdt_set_heartbeat(new_margin))
-
return -EINVAL;
-
s3c2410wdt_keepalive();
-
return put_user(tmr_margin, p);
-
case WDIOC_GETTIMEOUT:
-
return put_user(tmr_margin, p);
-
default:
-
return -ENOTTY;
-
}
-
}
-
-
/* kernel interface */
-
-
static const struct file_operations s3c2410wdt_fops = {
-
.owner = THIS_MODULE,
-
.llseek = no_llseek,
-
.write = s3c2410wdt_write,
-
.unlocked_ioctl = s3c2410wdt_ioctl,
-
.open = s3c2410wdt_open,
-
.release = s3c2410wdt_release,
-
};
-
-
static struct miscdevice s3c2410wdt_miscdev = {
-
.minor = WATCHDOG_MINOR,
-
.name = "watchdog",
-
.fops = &s3c2410wdt_fops,
-
};
-
-
/* interrupt handler code */
-
-
static irqreturn_t s3c2410wdt_irq(int irqno, void *param)
-
{
-
dev_info(wdt_dev, "watchdog timer expired (irq)\n");
-
-
s3c2410wdt_keepalive();
-
return IRQ_HANDLED;
-
}
-
/* device interface */
-
-
static int __devinit s3c2410wdt_probe(struct platform_device *pdev)
-
{
-
struct resource *res;
-
struct device *dev;
-
unsigned int wtcon;
-
int started = 0;
-
int ret;
-
int size;
-
-
DBG("%s: probe=%p\n", __func__, pdev);
-
-
dev = &pdev->dev;
-
wdt_dev = &pdev->dev;
-
-
/* get the memory region for the watchdog timer -- flags is IORESOURCE_MEM */
-
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-
if (res == NULL) {
-
dev_err(dev, "no memory resource specified\n");
-
return -ENOENT;
-
}
-
-
size = (res->end - res->start) + 1;
-
-
//请求分配指定的I/O内存资源
-
wdt_mem = request_mem_region(res->start, size, pdev->name);
-
if (wdt_mem == NULL) {
-
dev_err(dev, "failed to get memory region\n");
-
ret = -ENOENT;
-
goto err_req;
-
}
-
-
//将一个IO地址空间映射到内核的虚拟地址空间上去,便于访问
-
wdt_base = ioremap(res->start, size);
-
if (wdt_base == NULL) {
-
dev_err(dev, "failed to ioremap() region\n");
-
ret = -EINVAL;
-
goto err_req;
-
}
-
-
DBG("probe: mapped wdt_base=%p\n", wdt_base);
-
-
/* get the memory region for the watchdog timer -- flags is IORESOURCE_IRQ */
-
wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-
if (wdt_irq == NULL) {
-
dev_err(dev, "no irq resource specified\n");
-
ret = -ENOENT;
-
goto err_map;
-
}
-
-
//注册中断服务函数s3c2410wdt_irq()
-
ret = request_irq(wdt_irq->start, s3c2410wdt_irq, 0, pdev->name, pdev);
-
if (ret != 0) {
-
dev_err(dev, "failed to install irq (%d)\n", ret);
-
goto err_map;
-
}
-
-
//从平台时钟队列中获取clk
-
wdt_clock = clk_get(&pdev->dev, "watchdog");
-
if (IS_ERR(wdt_clock)) {
-
dev_err(dev, "failed to find watchdog clock source\n");
-
ret = PTR_ERR(wdt_clock);
-
goto err_irq;
-
}
-
-
//inform the system when the clock source should be running
-
clk_enable(wdt_clock);
-
-
/* see if we can actually set the requested timer margin, and if
-
* not, try the default value */
-
-
if (s3c2410wdt_set_heartbeat(tmr_margin)) {
-
started = s3c2410wdt_set_heartbeat(
-
CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
-
-
if (started == 0)
-
dev_info(dev,
-
"tmr_margin value out of range, default %d used\n",
-
CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
-
else
-
dev_info(dev, "default timer value is out of range, "
-
"cannot start\n");
-
}
-
-
ret = misc_register(&s3c2410wdt_miscdev);
-
if (ret) {
-
dev_err(dev, "cannot register miscdev on minor=%d (%d)\n",
-
WATCHDOG_MINOR, ret);
-
goto err_clk;
-
}
-
-
if (tmr_atboot && started == 0) {
-
dev_info(dev, "starting watchdog timer\n");
-
s3c2410wdt_start();
-
} else if (!tmr_atboot) {
-
/* if we're not enabling the watchdog, then ensure it is
-
* disabled if it has been left running from the bootloader
-
* or other source */
-
-
s3c2410wdt_stop();
-
}
-
-
/* print out a statement of readiness */
-
-
wtcon = readl(wdt_base + S3C2410_WTCON);
-
-
dev_info(dev, "watchdog %sactive, reset %sabled, irq %sabled\n",
-
(wtcon & S3C2410_WTCON_ENABLE) ? "" : "in",
-
(wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis",
-
(wtcon & S3C2410_WTCON_INTEN) ? "" : "en");
-
-
return 0;
-
-
err_clk:
-
clk_disable(wdt_clock);
-
clk_put(wdt_clock);
-
-
err_irq:
-
free_irq(wdt_irq->start, pdev);
-
-
err_map:
-
iounmap(wdt_base);
-
-
err_req:
-
release_resource(wdt_mem);
-
kfree(wdt_mem);
-
-
return ret;
-
}
-
-
static int __devexit s3c2410wdt_remove(struct platform_device *dev)
-
{
-
release_resource(wdt_mem);
-
kfree(wdt_mem);
-
wdt_mem = NULL;
-
-
free_irq(wdt_irq->start, dev);
-
wdt_irq = NULL;
-
-
clk_disable(wdt_clock);
-
clk_put(wdt_clock);
-
wdt_clock = NULL;
-
-
iounmap(wdt_base);
-
misc_deregister(&s3c2410wdt_miscdev);
-
return 0;
-
}
-
-
static void s3c2410wdt_shutdown(struct platform_device *dev)
-
{
-
s3c2410wdt_stop();
-
}
-
-
#ifdef CONFIG_PM
-
-
static unsigned long wtcon_save;
-
static unsigned long wtdat_save;
-
-
static int s3c2410wdt_suspend(struct platform_device *dev, pm_message_t state)
-
{
-
/* Save watchdog state, and turn it off. */
-
wtcon_save = readl(wdt_base + S3C2410_WTCON);
-
wtdat_save = readl(wdt_base + S3C2410_WTDAT);
-
-
/* Note that WTCNT doesn't need to be saved. */
-
s3c2410wdt_stop();
-
-
return 0;
-
}
-
-
static int s3c2410wdt_resume(struct platform_device *dev)
-
{
-
/* Restore watchdog state. */
-
-
writel(wtdat_save, wdt_base + S3C2410_WTDAT);
-
writel(wtdat_save, wdt_base + S3C2410_WTCNT); /* Reset count */
-
writel(wtcon_save, wdt_base + S3C2410_WTCON);
-
-
printk(KERN_INFO PFX "watchdog %sabled\n",
-
(wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis");
-
-
return 0;
-
}
-
#else
-
#define s3c2410wdt_suspend NULL
-
#define s3c2410wdt_resume NULL
-
#endif /* CONFIG_PM */
-
-
-
/*
-
*platform_driver s3c2410wdt_driver 与 platform_device s3c_device_wdt 对应
-
*s3c_device_wdt 在arch/arm/plat-s3c24xx/devs.c中定义
-
*两者的工作顺序是先定义platform_device -> 注册 platform_device->
-
*在mini2440_machine_init()中完成
-
*再定义 platform_driver-> 注册 platform_driver
-
*/
-
static struct platform_driver s3c2410wdt_driver = {
-
.probe = s3c2410wdt_probe, //设备的检测,所以需要先注册设备
-
.remove = __devexit_p(s3c2410wdt_remove), //删除该设备
-
.shutdown = s3c2410wdt_shutdown, //关闭该设备
-
.suspend = s3c2410wdt_suspend,
-
.resume = s3c2410wdt_resume,
-
.driver = { //设备驱动
-
.owner = THIS_MODULE,
- /*
*对应 struct platform_device s3c_device_wdt = {
* .name = "s3c2410-wdt",
* ...
* };
*/
-
.name = "s3c2410-wdt",
-
},
-
};
-
-
-
static char banner[] __initdata =
-
KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
-
-
static int __init watchdog_init(void) //模块初始化
-
{
-
printk(banner); //打印信息
-
return platform_driver_register(&s3c2410wdt_driver); //注册设备的驱动程序
-
}
-
-
static void __exit watchdog_exit(void) //移除模块
-
{
-
platform_driver_unregister(&s3c2410wdt_driver); //unregister a driver for platform-level devices
-
}
-
-
module_init(watchdog_init);
-
module_exit(watchdog_exit);
-
-
MODULE_AUTHOR("Ben Dooks , "
-
"Dimitry Andric ");
-
MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
-
MODULE_LICENSE("GPL");
-
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
-
MODULE_ALIAS("platform:s3c2410-wdt");
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