linux看门狗设备,基于Linux构建无人值守系统（看门狗）

基于Linux构建无人值守系统(看门狗)

在各种嵌入式设备soc中基本都提供了看门狗，在很长一段时间里我对看门狗的理解就是“关掉它，不然它会找麻烦”。但是当某种需求存在的时候，它又是必不可少的，比如你的产品是一个类似路由器的服务设备，可能在阳台的某刻角落一丢就是好几年，虽然孤独听起来让人伤感，可是如果在孤独中死去，那就会给客户带来更大的烦恼。所以我们应该去了解它

讲解中使用的环境主要基于linux系统，设备是arm s3c6410

#include

#include

#include

#include

#include

#include

#include

staticint wdt_probe(struct platform_device * dev);

staticint wdt_remove(struct platform_device * dev);

struct wdt_driver

{

struct platform_driver pdrv;

unsigned long phys_regs;

unsigned long phys_regs_len;

struct timer_list timer;

int irq;

void * regs;

};

staticstruct wdt_driver wdtdrv =

{

.pdrv =

{

.probe = wdt_probe,

.remove = wdt_remove,

.driver =

{

.name = "s3c2410-wdt",

.owner = THIS_MODULE,

},

},

};

irqreturn_t wdt_irq(int irq,void * data)

{

struct wdt_driver * wdtdrv = data;

iowrite32(1,wdtdrv->regs+0xc);

printk("wdt_irqn");

return IRQ_HANDLED;

}

void wdt_timeout(unsigned long data)

{//喂狗

struct wdt_driver * wdtdrv = (void *)data;

//printk("wdt_timeoutn");

iowrite32(3764,wdtdrv->regs+8);

mod_timer(&wdtdrv->timer,jiffies+HZ/2);

}

//pclk 66500000

staticint wdt_init(struct wdt_driver * wdtdrv)

{

iowrite32(3764,wdtdrv->regs+4);

iowrite32(3764,wdtdrv->regs+8);

//狗中断

//iowrite32(0x80<<8|0x1<<5|0x1<<2|0x3<<3,wdtdrv->regs);

//狗reset

iowrite32(0x80<<8|0x1<<5|0x3<<3|1,wdtdrv->regs);

printk("WTCON=%xn",ioread32(wdtdrv->regs));

printk("WTDAT=%xn",ioread32(wdtdrv->regs+4));

printk("WTCNT=%xn",ioread32(wdtdrv->regs+8));

//启动喂狗定时器

setup_timer(&wdtdrv->timer, wdt_timeout,(unsigned long)wdtdrv);

mod_timer(&wdtdrv->timer,jiffies+HZ/2);

//狗超时中断

// if(!request_irq(wdtdrv->irq,wdt_irq,IRQF_TRIGGER_FALLING,"wdt",wdtdrv))

// goto err_timer;

return 0;

}

staticint wdt_destroy(struct wdt_driver * wdtdrv)

{

//狗timer停止运行

iowrite32(0x80<<8|0<<5|0x3<<3|1,wdtdrv->regs);

//启动喂狗定时器

del_timer(&wdtdrv->timer);

//狗超时中断

//free_irq(wdtdrv->irq,(unsigned long)wdtdrv);

return 0;

}

staticint wdt_probe(struct platform_device * dev)

{

struct wdt_driver * wdtdrv;

struct resource * res;

printk("wdt_probe:%sn",dev->name);

wdtdrv = container_of(container_of(dev->dev.driver,struct platform_driver,driver),struct wdt_driver,pdrv);

//获取控制器寄存器地址

res = platform_get_resource(dev,IORESOURCE_MEM,0);

if(!res)

goto err_out;

wdtdrv->phys_regs = res->start;

wdtdrv->phys_regs_len = res->end-res->start;

wdtdrv->regs = ioremap(wdtdrv->phys_regs,wdtdrv->phys_regs_len);

if(!wdtdrv->regs)

goto err_out;

if(!request_mem_region(wdtdrv->phys_regs,wdtdrv->phys_regs_len,dev_name(&dev->dev)))

goto err_ioremap;

//获取中断

wdtdrv->irq = platform_get_irq(dev,0);

if(wdtdrv->irq<0)

goto err_request_mem;

printk("irq=%dn",wdtdrv->irq);

wdt_init(wdtdrv);

return 0;

err_request_mem:

release_mem_region(wdtdrv->phys_regs,wdtdrv->phys_regs_len);

err_ioremap:

iounmap(wdtdrv->regs);

err_out:

return -1;

}

staticint wdt_remove(struct platform_device * dev)

{

struct wdt_driver * wdtdrv;

printk("wdt_remove:%sn",dev->name);

wdtdrv = container_of(container_of(dev->dev.driver,struct platform_driver,driver),struct wdt_driver,pdrv);

wdt_destroy(wdtdrv);

release_mem_region(wdtdrv->phys_regs,wdtdrv->phys_regs_len);

iounmap(wdtdrv->regs);

return 0;

}

staticint modinit(void)

{

printk("mod initn");

platform_driver_register(&wdtdrv.pdrv);

return 0;

}

staticvoid modexit(void)

{

platform_driver_unregister(&wdtdrv.pdrv);

printk("mod exitn");

}

module_init(modinit);

module_exit(modexit);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("dragon101788");

首先对模块进行初始化

module_init(modinit);

module_exit(modexit);

从平台中通过文件名"s3c2410-wdt"找出设备，回调wdt_probe

当然你的确定arch/arm/mach-s3c64xx/mach-s3c6410的static struct platform_device *smdk6410_devices[] __initdata中找到&s3c_device_wdt,，如果没有，看看arch/arm/plat-samsung/中有没有dev-wdt.c文件搞到里面的platform_device对象，添加到__initdata中。