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);

 

/* linux/drivers/ker-driver.c * Author: Woodpecker <[email protected]> * * kernel-driver * * This file is subject to the terms and conditions of the GNU General Public * License. See the file COPYING in the main directory of this archive for * more details. * */ #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); 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 <[email protected]>"); MODULE_DESCRIPTION("Kernel driver"); MODULE_LICENSE("GPL");

 

驱动的运行结果：

 

2010/09/09