hrtimer和work工作队列的使用

太过爱你忘了你带给我的痛 2022-07-13 11:08 160阅读 0赞

1.hrtimers - 为高分辨率kernel定时器，可作为超时或周期性定时器使用

# 1). hrtimer\_init初始化定时器工作模式。 #

hrtimer\_init(&vibe\_timer, CLOCK\_MONOTONIC, HRTIMER\_MODE\_REL);  
vibe\_timer.function = vibrator\_timer\_func;

/\* 设置定时器的回调函数，定时器到时该函数将被调用 \*/

static enum hrtimer\_restart vibrator\_timer\_func(struct hrtimer \*timer)

**注：该回调函数为原子操作不能被中断**

# 2). hrtimer\_start的第二个参数用于设置超时参数。 #

#  #

hrtimer\_start(&vibe\_timer,  
ktime\_set(value / 1000, (value % 1000) \* 1000000),HRTIMER\_MODE\_REL);

# 3). INIT\_WORK初始化工作队列。 #

INIT\_WORK(&vibe\_work, vibe\_work\_func);

static void vibe\_work\_func(struct work\_struct \*work)

# 4). schedule\_work调用工作队列。 #

schedule\_work(&vibe\_work);

# 5 例子代码    #

#include <linux/module.h>     /* MODULE_LICENSE     */  
    #include <linux/kernel.h>     /* printk,pr_info     */  
    #include <linux/errno.h>      /* EINVAL,EAGAIN,etc. */  
    #include <linux/err.h>            /* IS_ERR             */  
    #include <linux/fb.h>         /* FB header file     */  
    #include <linux/init.h>           /* module_init        */  
    #include <linux/semaphore.h>  /* init_MUTEX APIs    */  
    #include <linux/mm.h>         /* vm_area_struct     */  
    #include <linux/dma-mapping.h>  /* DMA APIs             */  
    #include <linux/delay.h>      /* mdelay,msleep      */  
    #include <linux/hrtimer.h>   
    #include <linux/time.h>           /* struct timespec    */  
      
    #define KER_PRINT(fmt, ...) printk("<ker-driver>"fmt, ##__VA_ARGS__);  
    static struct hrtimer vibe_timer;  
    static struct work_struct vibe_work;  
      
    static void vibe_work_func(struct work_struct *work)  
    {  
        KER_PRINT("vibe_work_func:msleep(50)/n");  
        msleep(50); /* CPU sleep */  
    }  
      
    static enum hrtimer_restart vibrator_timer_func(struct hrtimer *timer)   
    {             
        struct timespec uptime;  
          
        do_posix_clock_monotonic_gettime(&uptime);  
        KER_PRINT("Time:%lu.%02lu/n",  
                (unsigned long) uptime.tv_sec,  
                (uptime.tv_nsec / (NSEC_PER_SEC / 100)));  
          
        KER_PRINT("vibrator_timer_func/n");   
        schedule_work(&vibe_work);  
        return HRTIMER_NORESTART;  
    }  
      
    static int __init ker_driver_init(void)  
    {  
      
        int value = 2000;   /* Time out setting,2 seconds */  
        struct timespec uptime;  
          
        KER_PRINT("ker_driver_init/n");  
        hrtimer_init(&vibe_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);  
        vibe_timer.function = vibrator_timer_func;  
        hrtimer_start(&vibe_timer,  
            ktime_set(value / 1000, (value % 1000) * 1000000),HRTIMER_MODE_REL);  
          //static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)  第一个参数为秒，第二个为纳秒
        do_posix_clock_monotonic_gettime(&uptime);  
        KER_PRINT("Time:%lu.%02lu/n",  
                (unsigned long) uptime.tv_sec,  
                (uptime.tv_nsec / (NSEC_PER_SEC / 100)));  
      
        INIT_WORK(&vibe_work, vibe_work_func);  /* Intialize the work queue */  
        return 0;  
      
    }  
      
    static void __exit ker_driver_exit(void)  
    {  
        hrtimer_cancel(&vibe_timer);  
    }  
      
    module_init(ker_driver_init);  
    module_exit(ker_driver_exit);  
      
    MODULE_AUTHOR("Woodpecker <Pecker.hu@gmail.com>");  
    MODULE_DESCRIPTION("Kernel driver");  
    MODULE_LICENSE("GPL");

# 6 测试结果 #

![20170106161402511][]

[20170106161402511]: /images/20220713/b2ef9b9a000d4419a3ef7a4a7a2bbd48.png