Linux驅動:互斥鎖mutex測試

環境：

主機:Fedora 12

目標板：MINI6410

目標板LINUX內核版本：2.6.38

互斥鎖主要函數:

//創建互斥鎖

//加鎖,如果加鎖不成功，會阻塞當前進程

void mutex_lock(struct mutex *lock);

//解鎖

void mutex_unlock(struct mutex *lock);

//嘗試加鎖，會立即返回，不會阻塞進程

int mutex_trylock(struct mutex *lock);

測試代碼:

1. #include <linux/miscdevice.h>
2. #include <linux/delay.h>
3. #include <asm/irq.h>
4. //#include <mach/regs-gpio.h>
5. #include <mach/hardware.h>
6. #include <linux/kernel.h>
7. #include <linux/module.h>
8. #include <linux/init.h>
9. #include <linux/mm.h>
10. #include <linux/fs.h>
11. #include <linux/types.h>
12. #include <linux/delay.h>
13. #include <linux/moduleparam.h>
14. #include <linux/slab.h>
15. #include <linux/errno.h>
16. #include <linux/ioctl.h>
17. #include <linux/cdev.h>
18. #include <linux/string.h>
19. #include <linux/list.h>
20. #include <linux/pci.h>
21. #include <asm/uaccess.h>
22. #include <asm/atomic.h>
23. #include <asm/unistd.h>
24. #include <linux/major.h>
26. #include <mach/map.h>
27. #include <mach/regs-clock.h>
28. #include <mach/regs-gpio.h>
30. #include <plat/gpio-cfg.h>
31. #include <mach/gpio-bank-e.h>
32. #include <mach/gpio-bank-k.h>
33. #include <mach/gpio-bank-h.h>
34. #include <mach/gpio-bank-n.h>
35. #include <mach/gpio-bank-l.h>
36. #include <mach/gpio-bank-p.h>
38. #include <linux/device.h>
40. #include <linux/jiffies.h>
42. #define DEVICE_NAME "led_driver"
43. #define T_MAJORS 700
45. static struct cdev fun_cdev;
46. static dev_t dev;
47. static struct class *led_class;
49. //初始化互斥鎖
50. static DEFINE_MUTEX(sem);
52. //功能：初始化IO
53. static void init_led(void)
54. {
55. unsigned temp;
57. //GPK4-7設置為輸出
58. temp = readl(S3C64XX_GPKCON);
59. temp &= ~((0xf << 4) | (0xf << 5) | (0xf << 6) | (0xf<< 7));
60. temp |= (1 << 16) | (1 << 20) | (1 << 24) | (1 << 28);
61. writel(temp, S3C64XX_GPKCON);
62. }
64. //功能：ioctl操作函數
65. //返回值：成功返回0
66. static long led_driver_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
67. {
68. unsigned int temp = 0;
69. //unsigned long t = 0;
70. wait_queue_head_t wait;
72. //加鎖
73. mutex_lock(&sem);
75. temp = readl(S3C64XX_GPKDAT);
76. if (cmd == 0)
77. {
78. temp &= ~(1 << (arg + 3));
79. }
80. else
81. {
82. temp |= 1 << (arg + 3);
83. }
85. //等待2S
86. //t = jiffies;
87. //while (time_after(jiffies,t + 2 * HZ) != 1);
88. init_waitqueue_head(&wait);
89. sleep_on_timeout(&wait,2 * HZ);
90. writel(temp,S3C64XX_GPKDAT);
92. printk (DEVICE_NAME"\tjdh:led_driver cmd=%d arg=%d jiffies = %d\n",cmd,arg,jiffies);
94. //解鎖
95. mutex_unlock(&sem);
97. return 0;
98. }
100. static struct file_operations io_dev_fops = {
101. .owner = THIS_MODULE,
102. .unlocked_ioctl = led_driver_ioctl,
103. };
105. static int __init dev_init(void)
106. {
107. int ret;
108. unsigned temp;
110. init_led();
112. dev = MKDEV(T_MAJORS,0);
113. cdev_init(&fun_cdev,&io_dev_fops);
114. ret = register_chrdev_region(dev,1,DEVICE_NAME);
115. if (ret < 0) return 0;
116. ret = cdev_add(&fun_cdev,dev,1);
117. if (ret < 0) return 0;
119. printk (DEVICE_NAME"\tjdh:led_driver initialized!!\n");
121. led_class = class_create(THIS_MODULE, "led_class1");
122. if (IS_ERR(led_class))
123. {
124. printk(KERN_INFO "create class error\n");
125. return -1;
126. }
127. device_create(led_class, NULL, dev, NULL, "led_driver");
129. return ret;
130. }
132. static void __exit dev_exit(void)
133. {
134. unregister_chrdev_region(dev,1);
136. device_destroy(led_class, dev);
137. class_destroy(led_class);
138. }
140. module_init(dev_init);
141. module_exit(dev_exit);
142. MODULE_LICENSE("GPL");
143. MODULE_AUTHOR("JDH");

測試

開啟兩個程序，同時打開，雙進程同時操作LED