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Linux驱动:互斥锁mutex测试
本文博客链接:,作者:jdh,转载请注明.
环境：
主机:Fedora12
目标板：MINI6410
目标板版本：2.6.38
互斥锁主要函数:
//创建互斥锁
DEFINE_MUTEX(mutexname);//加锁,如果加锁不成功，会阻塞当前进程
void mutex_lock(struct mutex *lock);
//解锁
void mutex_unlock(struct mutex *lock);
//尝试加锁，会立即返回，不会阻塞进程
int mutex_trylock(struct mutex *lock);
测试代码:
#include#include #include //#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DEVICE_NAME "led_driver"#define T_MAJORS 700static struct cdev fun_cdev;static dev_t dev;static struct class *led_class;//初始化互斥锁static DEFINE_MUTEX(sem);//功能：初始化IOstatic void init_led(void){ unsigned temp; //GPK4-7设置为输出 temp = readl(S3C64XX_GPKCON); temp &= ~((0xf << 4) | (0xf << 5) | (0xf << 6) | (0xf<< 7)); temp |= (1 << 16) | (1 << 20) | (1 << 24) | (1 << 28); writel(temp, S3C64XX_GPKCON);}//功能：ioctl操作函数//返回值：成功返回0static long led_driver_ioctl(struct file *filp, unsigned int cmd, unsigned long arg){ unsigned int temp = 0; //unsigned long t = 0; wait_queue_head_t wait; //加锁 mutex_lock(&sem); temp = readl(S3C64XX_GPKDAT); if (cmd == 0) { temp &= ~(1 << (arg + 3)); } else { temp |= 1 << (arg + 3); } //等待2S //t = jiffies; //while (time_after(jiffies,t + 2 * HZ) != 1); init_waitqueue_head(&wait); sleep_on_timeout(&wait,2 * HZ); writel(temp,S3C64XX_GPKDAT); printk (DEVICE_NAME"\tjdh:led_driver cmd=%d arg=%d jiffies = %d\n",cmd,arg,jiffies); //解锁 mutex_unlock(&sem); return 0;}static struct file_operations io_dev_fops = { .owner = THIS_MODULE, .unlocked_ioctl = led_driver_ioctl,};static int __init dev_init(void){ int ret; unsigned temp; init_led(); dev = MKDEV(T_MAJORS,0); cdev_init(&fun_cdev,&io_dev_fops); ret = register_chrdev_region(dev,1,DEVICE_NAME); if (ret < 0) return 0; ret = cdev_add(&fun_cdev,dev,1); if (ret < 0) return 0; printk (DEVICE_NAME"\tjdh:led_driver initialized!!\n"); led_class = class_create(THIS_MODULE, "led_class1"); if (IS_ERR(led_class)) { printk(KERN_INFO "create class error\n"); return -1; } device_create(led_class, NULL, dev, NULL, "led_driver"); return ret;}static void __exit dev_exit(void){ unregister_chrdev_region(dev,1); device_destroy(led_class, dev); class_destroy(led_class);}module_init(dev_init);module_exit(dev_exit);MODULE_LICENSE("GPL");MODULE_AUTHOR("JDH");
测试
用中的测试程序进行测试：开启两个程序，同时打开，双进程同时操作LED
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