【海思篇】【Hi3516DV300】十五、看门狗（watchdog）

看门狗（watchdog）"/>

【海思篇】【Hi3516DV300】十五、看门狗（watchdog）

watchdog概述

看门狗一般应用于系统异常或者核心应用异常，一定时间内发出复位信号，以复位整个系统。
我将分三个层次来说明：
1 寄存器层
2 驱动层
3 应用层

1 寄存器层

hi3516dv300有2个watchdog模块；
WatchDog 0 基址：0x1205_0000。
WatchDog 1 基址：0x1205_1000

watchdog寄存器概览

计数时钟频率配置

watchdog计数时钟为3MHz时钟。
time=val*1/fclk
time：watchdog计数时间
val：watchdog计数初值
fclk：watchdog计数时钟频率
watchdog的计数时间time范围为0s~1400s

系统初始化配置

系统上电复位后wat计数器处于停止计数状态。

1. 写寄存器WDG_LOAD，设定计数初值
2. 写寄存器 WDG_CONTROL，打开中断屏蔽并启动 WatchDog 计数。
3. 写寄存器 WDG_LOCK，给 WatchDog 上锁，防止软件错误修改 WatchDog 的配置。

中断处理过程处理

收到watchdog发出的中断后，要清除其中断状态，并使其载入计数初值重新开始计数，该过程可以表述为喂狗。如果计数器的计数值第二次计数递减到0时，CPU还没有清除watchdog中断，则watchdog将发出复位信号WDG_RSTN，系统将重启。

1. 写寄存器WDG_LOCK，固定值0x1ACC_E551，为watchdog开锁。
2. 写寄存器WDG_INTCLR，清除watchdog的中断状态，同时也是watchdog自动载入计数初值重新开始计数。
3. 写寄存器WDG_LOCK，除0x1ACC_E551以外的任何值，给watchdog上锁。

开启关闭watchdog

写寄存器WDG_CONTROL[inten]控制位：
0： 关闭watchdog
1：开启watchdog

2 驱动层

这里我不贴出所有代码，sdk中有该驱动源码，位置为Hi3516CV500_SDK_V2.0.1.1/smp/a7_linux/drv/interdrv/wdt/hi_wdt.c

/* define watchdog IO */
#define HIWDT_BASE      0x12051000
#define HIWDT_REG(x)    (HIWDT_BASE + (x))#define HIWDT_LOAD      0x000
#define HIWDT_VALUE     0x004
#define HIWDT_CTRL      0x008
#define HIWDT_INTCLR    0x00C
#define HIWDT_RIS       0x010
#define HIWDT_MIS       0x014
#define HIWDT_LOCK      0xC00#define HIWDT_UNLOCK_VAL    0x1ACCE551#ifndef MHZ
#define MHZ (1000*1000)
#endifstatic unsigned long rate = 3*MHZ;// 设置喂狗超时时间
static inline void hidog_set_timeout(unsigned int nr)
{unsigned long cnt = (~0x0UL)/rate;        /* max cnt */unsigned long flags;osal_spin_lock_irqsave(&hidog_lock, &flags);if( nr==0 || nr>cnt)cnt=~0x0;elsecnt = nr*rate;/* unlock watchdog registers */hiwdt_writel(HIWDT_UNLOCK_VAL, HIWDT_LOCK);hiwdt_writel(cnt, HIWDT_LOAD);hiwdt_writel(cnt, HIWDT_VALUE);/* lock watchdog registers */hiwdt_writel(0, HIWDT_LOCK);osal_spin_unlock_irqrestore(&hidog_lock, &flags);
};// 喂狗
static inline void hidog_feed(void)
{unsigned long flags;/* read the RIS state of current wdg */int v=0;v = hiwdt_readl(HIWDT_RIS);v &= 0x1;if (0 == v) /*no INT on current wdg */return;osal_spin_lock_irqsave(&hidog_lock, &flags);/* unlock watchdog registers */hiwdt_writel(HIWDT_UNLOCK_VAL, HIWDT_LOCK);/* clear watchdog */hiwdt_writel(0x00, HIWDT_INTCLR);/* lock watchdog registers */hiwdt_writel(0, HIWDT_LOCK);osal_spin_unlock_irqrestore(&hidog_lock, &flags);
};// 唤醒狗
static inline void hidog_start(void)
{unsigned long flags;//unsigned long t;osal_spin_lock_irqsave(&hidog_lock, &flags);/* unlock watchdog registers */hiwdt_writel(HIWDT_UNLOCK_VAL, HIWDT_LOCK);hiwdt_writel(0x00, HIWDT_CTRL);hiwdt_writel(0x00, HIWDT_INTCLR);hiwdt_writel(0x03, HIWDT_CTRL);/* lock watchdog registers */hiwdt_writel(0, HIWDT_LOCK);/* enable watchdog clock --- set the frequency to 3MHz *///t = osal_readl(reg_ctl_base_va);//osal_writel(t & ~0x00800000, reg_ctl_base_va);osal_spin_unlock_irqrestore(&hidog_lock, &flags);options = WDIOS_ENABLECARD;
}// 关狗
static inline void hidog_stop(void)
{unsigned long flags;osal_spin_lock_irqsave(&hidog_lock, &flags);/* unlock watchdog registers */hiwdt_writel(HIWDT_UNLOCK_VAL, HIWDT_LOCK);/* stop watchdog timer */hiwdt_writel(0x00, HIWDT_CTRL);hiwdt_writel(0x00, HIWDT_INTCLR);/* lock watchdog registers */hiwdt_writel(0, HIWDT_LOCK);osal_spin_unlock_irqrestore(&hidog_lock, &flags);hidog_set_timeout(0);options = WDIOS_DISABLECARD;
}

3 应用层

功能接口

/**
* @brief    create watchdog task
* @param[in] s32TimeOut: feed dog time, [2, MAX]
* @return 0 success,non-zero error code.
*/
HI_S32 HI_HAL_WATCHDOG_Init(HI_S32 s32TimeOut);/**
* @brief    feed watchdog
* @return 0 success,non-zero error code.
*/
HI_S32 HI_HAL_WATCHDOG_Feed(HI_VOID);/**
* @brief    destroy watchdog task
* @return 0 success,non-zero error code.
*/
HI_S32 HI_HAL_WATCHDOG_Deinit(HI_VOID);

功能实现

#define HI_APPCOMM_MAX_PATH_LEN (64)
#define HAL_FD_INITIALIZATION_VAL (-1)
#define HAL_WATCHDOG_DEV "/dev/watchdog"
static HI_S32 s_s32HALWATCHDOGfd = HAL_FD_INITIALIZATION_VAL;HI_S32 HI_WATCHDOG_Init(HI_S32 s32Time_s)
{HI_S32 s32Ret = HI_SUCCESS;if (s_s32HALWATCHDOGfd != HAL_FD_INITIALIZATION_VAL){MLOGE("already init");return HI_HAL_EINITIALIZED;}if (s32Time_s < 2 || s32Time_s > 1000){MLOGE("Interval time should not be less then two and bigger then 100. %d\n", s32Time_s);return HI_HAL_EINVAL;}HI_CHAR szWdtString[HI_APPCOMM_MAX_PATH_LEN] = {0};snprintf(szWdtString, HI_APPCOMM_MAX_PATH_LEN, " default_margin=%d nodeamon=1", s32Time_s);#if defined(HI3559V200)s32Ret = HI_insmod(HI_APPFS_KOMOD_PATH"/hi3559v200_wdt.ko",szWdtString);if(HI_SUCCESS != s32Ret){MLOGE("insmod 3c3416: failed, errno(%d)\n", errno);return HI_HAL_EINTER;}
#elif defined(__HI3516DV300__) s32Ret = HI_insmod("/komod/hi3516cv500_wdt.ko",NULL);if(HI_SUCCESS != s32Ret && errno != EEXIST){MLOGE("insmod hi3516cv500_wdt.ko: failed, errno(%d)\n", errno);return HI_HAL_EINTER;}
#endifs_s32HALWATCHDOGfd = open(HAL_WATCHDOG_DEV, O_RDWR);if (s_s32HALWATCHDOGfd < 0){MLOGE("open [%s] failed\n",HAL_WATCHDOG_DEV);return HI_HAL_EINVOKESYS;}#if defined(__HI3516DV300__ ) s32Ret = ioctl(s_s32HALWATCHDOGfd, WDIOC_SETTIMEOUT, &s32Time_s);if(-1 == s32Ret){MLOGE("WDIOC_SETTIMEOUT: failed, errno(%d)\n", errno);return HI_HAL_EINTER;}MLOGI(BLUE"WDIOC_SETTIMEOUT: timeout=%ds\n"NONE, s32Time_s);
#endifs32Ret = ioctl(s_s32HALWATCHDOGfd, WDIOC_KEEPALIVE);/**feed dog */if(-1 == s32Ret){MLOGE("WDIOC_KEEPALIVE: failed, errno(%d)\n", errno);return HI_HAL_EINTER;}return HI_SUCCESS;
}HI_S32 HI_HAL_WATCHDOG_Feed(HI_VOID)
{HI_S32 s32Ret = HI_SUCCESS;s32Ret = ioctl(s_s32HALWATCHDOGfd, WDIOC_KEEPALIVE);/**feed dog */if(-1 == s32Ret){MLOGE("WDIOC_KEEPALIVE: failed, errno(%d)\n", errno);return HI_HAL_EINTER;}return HI_SUCCESS;
}HI_S32 HI_HAL_WATCHDOG_Deinit(HI_VOID)
{HI_S32 s32Ret;if (s_s32HALWATCHDOGfd == HAL_FD_INITIALIZATION_VAL){MLOGE("watchdog not initialized,no need to close\n");return HI_HAL_ENOINIT;}s32Ret = close(s_s32HALWATCHDOGfd);if (0 > s32Ret){MLOGE("wdrfd[%d] close,fail,errno(%d)\n",s_s32HALWATCHDOGfd,errno);return HI_HAL_EINVOKESYS;}s_s32HALWATCHDOGfd = HAL_FD_INITIALIZATION_VAL;return HI_SUCCESS;
}