hrtimer和work工作队列的使用

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 <[e-mail]>");  MODULE_DESCRIPTION("Kernel driver");  MODULE_LICENSE("GPL");  

6 测试结果