【吃灰板子捡起来】内核定时器实验

内核定时器实验

一、相关知识
二、驱动源码
三、APP源码
四、实验总结

一、相关知识

jiffies

extern u64 __jiffy_data jiffies_64;
extern unsigned long volatile __jiffy_data jiffies;

/** Convert various time units to each other:*/
extern unsigned int jiffies_to_msecs(const unsigned long j);
extern unsigned int jiffies_to_usecs(const unsigned long j);
extern unsigned long msecs_to_jiffies(const unsigned int m);
extern unsigned long usecs_to_jiffies(const unsigned int u);

timer_list

struct timer_list {/** All fields that change during normal runtime grouped to the* same cacheline*/struct list_head entry;unsigned long expires;struct tvec_base *base;void (*function)(unsigned long);unsigned long data;int slack;#ifdef CONFIG_TIMER_STATSint start_pid;void *start_site;char start_comm[16];
#endif
#ifdef CONFIG_LOCKDEPstruct lockdep_map lockdep_map;
#endif
};

二、驱动源码

#include "nuc972_gpio.h"#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/gpio.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/timer.h>#include <asm/mach/map.h>
#include <asm/uaccess.h>
#include <asm/io.h>#define TIMER_DEV_NUMS 1
#define TIMER_NAME "timerled"struct timer_dev{dev_t devid;int major;int minor;  struct cdev cdev;struct class *class;struct device *device;struct timer_list timer;
};struct timer_dev timerdev;/* */
#define SET_DIR 0X0100
#define GET_DIR 0X0200
#define SET_ODR 0X0300
#define GET_ODR 0X0400
#define GET_IDR 0X0500#define GPIOA 0x0000
#define GPIOB 0x0001
#define GPIOC 0x0002
#define GPIOD 0x0003
#define GPIOE 0x0004
#define GPIOF 0x0005
#define GPIOG 0x0006
#define GPIOH 0x0007
#define GPIOI 0x0008
#define GPIOJ 0x0009/* PF13-KEY1 PF14-KEY2 */
static int led_gpio_init(void)
{int temp;int ret = 0;set_gpio_direction(GPIOB,0xffff);set_gpio_odr(GPIOB,0xffff);return ret;
}void timer_function(unsigned long arg)
{int temp;temp = get_gpio_odr(GPIOB);if(temp &(int)(1<<4)){set_gpio_odr(GPIOB,~(unsigned short)(1<<4));}else{set_gpio_odr(GPIOB,0xffff); } mod_timer(&timerdev.timer,jiffies + msecs_to_jiffies(2000));
}
static int timerdev_open(struct inode *inode, struct file *filp)
{int ret = 0;init_timer(&timerdev.timer);timerdev.timer.function = timer_function;timerdev.timer.expires = jiffies + msecs_to_jiffies(2000);led_gpio_init();add_timer(&timerdev.timer);return 0;
}static ssize_t timerdev_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
{int temp;int ret = 0;temp = get_gpio_idr(GPIOF);ret = copy_to_user(buf,&temp,sizeof(temp));return 0;
}static int timerdev_release(struct inode *inode, struct file *filp)
{del_timer(&timerdev.timer);return 0;}static struct file_operations timerdev_fops = {.owner = THIS_MODULE,.open = timerdev_open,.read = timerdev_read,.release = timerdev_release,
};static int __init timer_init(void)
{int ret = 0; timerdev.major = 0;if(timerdev.major){timerdev.devid = MKDEV(timerdev.major, 0);ret = register_chrdev_region(timerdev.devid,TIMER_DEV_NUMS,TIMER_NAME);}else{ret = alloc_chrdev_region(&timerdev.devid,0,TIMER_DEV_NUMS,TIMER_NAME);   timerdev.major = MAJOR(timerdev.devid);timerdev.minor = MINOR(timerdev.devid);}if(ret < 0){printk("register chrdev failed!\r\n");goto fail_devid;}printk("timer major = %d, minor = %d \r\n", timerdev.major, timerdev.minor);cdev_init(&timerdev.cdev, &timerdev_fops);timerdev.cdev.owner = THIS_MODULE;ret = cdev_add(&timerdev.cdev, timerdev.devid, TIMER_DEV_NUMS);if(ret < 0){printk("cdev_add failed!\r\n");goto fail_cdevadd;}timerdev.class = class_create(THIS_MODULE, TIMER_NAME);if(IS_ERR(timerdev.class)){printk("class_create failed!\r\n");ret = PTR_ERR(timerdev.class);goto fail_class;}timerdev.device = device_create(timerdev.class, NULL, timerdev.devid, 0, TIMER_NAME);if(IS_ERR(timerdev.device)){printk("device_create failed!\r\n");ret = PTR_ERR(timerdev.device);goto fail_device;}printk("timer init success!\r\n");return 0; fail_device:class_destroy(timerdev.class);
fail_class:cdev_del(&timerdev.cdev);
fail_cdevadd:unregister_chrdev_region(timerdev.devid,TIMER_DEV_NUMS);
fail_devid:return ret;
}static void __exit timer_exit(void)
{del_timer(&timerdev.timer);device_destroy(timerdev.class,timerdev.devid);class_destroy(timerdev.class);cdev_del(&timerdev.cdev);unregister_chrdev_region(timerdev.devid, TIMER_DEV_NUMS);printk("timer_exit!\r\n");
}module_init(timer_init);
module_exit(timer_exit);MODULE_LICENSE("GPL");
MODULE_AUTHOR("mx");

三、APP源码

#include "stdio.h"
#include "string.h"
#include "stdlib.h"
#include "sys/types.h"
#include "sys/stat.h"
#include "fcntl.h"
#include "unistd.h"int main(int argc, char *argv[])
{int keyvalue = 0;int destvalue = 0;int fd;int ret = 0;char *filename;if(argc != 2){printf("Error Usage!\r\n");return -1;}filename = argv[1];fd = open(filename,O_RDWR);if(fd < 0){printf("file %s open failed!\r\n",filename);return -1;}destvalue = 1<<13;while(1){}close(fd);return 0;
}

四、实验总结

无

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【吃灰板子捡起来】内核定时器实验

内核定时器实验

一、相关知识

二、驱动源码

三、APP源码

四、实验总结

【吃灰板子捡起来】内核定时器实验相关推荐

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