linux驱动程序设计实例.doc

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1、AT91SAM9G20驱动程序设计开发环境：Vmware + ubuntu10.04硬件平台：AT91SAM9G20Linux版本：linux2.6.27一：led驱动说明：因为设计的开发板上没有led灯，便通过PC0来演示，通过示波器来观察引脚端的电平变化。1.驱动程序：my_led.c#include #include #include #include #include #include #include #define MY_LED_MAJOR250/定义主设备号#define LED_ON 0#define LED_OFF 1struct global_devstruct cdev

2、cdev;/定义设备结构体struct global_dev *global_devp;/定义一个指向设备结构体的指针static int my_led_open(struct inode *inode, struct file *filp)filp-private_data = global_devp;return 0;static int my_led_release(struct inode *inode, struct file *file)return 0;static int my_led_ioctl(struct inode *inode, struct file *filp,

3、unsigned int cmd, unsigned long data)switch(cmd)case LED_ON:at91_set_gpio_value(AT91_PIN_PC0, 0);/将PC0引脚置低break;case LED_OFF:at91_set_gpio_value(AT91_PIN_PC0, 1);/将PC1引脚置高break;default:printk(no valid cmd input!n);break;return 0;struct file_operations my_led_ctl_ops =.owner = THIS_MODULE,.open = my_

4、led_open,.release = my_led_release,.ioctl = my_led_ioctl,;/*初始化设备结构体*/static void my_led_setup(struct global_dev *dev, int index)int err;int devno = MKDEV(MY_LED_MAJOR, index);cdev_init(&dev-cdev, &my_led_ctl_ops);dev-cdev.owner = THIS_MODULE;dev-cdev.ops = &my_led_ctl_ops;err = cdev_add(&dev-cdev,

5、devno, 1);if(err)printk(add my led setup failed!n);static int my_led_init(void)int ret;dev_t devno = MKDEV(MY_LED_MAJOR, 0);/创建设备号printk(my first driver-led!n);at91_set_GPIO_periph(AT91_PIN_PC0, 1);at91_set_gpio_output(AT91_PIN_PC0, 1);/对PC0引脚的初始化ret = register_chrdev_region(devno, 1, my_led);/申请设备号

6、if( ret cdev);/删除设备kfree(global_devp);/释放内存unregister_chrdev_region(MKDEV(MY_LED_MAJOR, 0), 1);/释放设备号MODULE_LICENSE(MYGPL);MODULE_AUTHOR(FANY);module_init(my_led_init);/注册设备module_exit(my_led_cleanup);/卸载设备2:如何将驱动驱动程序编译成模块在drivers目录下新建led目录，并在该目录下添加Kconfig，Makefile文件。Kconfig：Menu My driver supportCo

7、nfig Trisate led driver!Help Led driverEndmenu:Makefile：Obj-$(CONFIG_MY_LED)+= my_led.o修改linux/drivers目录下的Kconfig，Makefile文件Kconfig:Source drivers/led/KconfigMakefile:Obj-y += my_led/修改体系结构目录arch/arm目录下的Kconfig文件，否则在配置菜单中将无法看到led的配置选项。（如果是在drivers目录下新建一文件夹，并在其中添加驱动程序，必须相应的体系结构目录下添加配置选项）。Kconfig:Sour

8、ce driver/led/Kconfig3.测试程序：my_led_test.c#include #include #include #include #include #define DEVICE_NAME /dev/my_led#define LED_ON0#define LED_OFF 1int main(void)int fd;int ret;int i;printf(my_led_driver test!n);fd = open(DEVICE_NAME, O_RDONLY);if(fd = -1)printf(open device %s error!n, DEVICE_NAME)

9、;for(i = 0; i 50; i+)ioctl(fd, LED_OFF);sleep(1);ioctl(fd, LED_ON);sleep(1);ret = close(fd);printf(ret = %dn, ret);printf(close my_led_driver!n);return 0;将测试程序编译成目标平台的可执行文件，并下载到开发板GCC=/home/zzq/9G20/arm-2007q1/bin/arm-none-linux-gnueabi-gcc #交叉编译器的路径My_led_test:my_led_test.c $(GCC) -o my_led_test my

10、_led_test.cclean: rm -f my_led_test学习总结：熟悉驱动程序的架构，如何将驱动程序添加到内核即如何写测试程序。二：按键驱动设计1.硬件部分：PC4接按键。2.驱动程序：#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define BUTTON_MAJOR245#define DEVICE_

11、NAME /dev/buttonstatic volatile int ev_press = 0;static struct cdev button_cdev;static void button_do_tasklet(unsigned long n);DECLARE_TASKLET(button_tasklet, button_do_tasklet, 0);/定义tasklet并与处理函数关联起来static DECLARE_WAIT_QUEUE_HEAD(button_waitq);/静态的初始化一个等待队列struct button_irq_desc int irq;int irq_ty

12、pe;int pin;int number;char *name;static struct button_irq_desc button_irq1 = AT91_PIN_PB22, AT91_AIC_SRCTYPE_LOW, AT91_PIN_PB22, 0, KEY0 ;static int key_values1=0;/中断处理底半部static void button_do_tasklet(unsigned long n)wake_up_interruptible(&button_waitq);/唤醒队列printk(button press!n);/中断处理顶半部static irq

13、return_t button_interrupt(int irq, void *dev_id, struct pt_regs *regs)int up; static int press_down;up = gpio_get_value(button_irq0.pin);printk(irqn);/*按键消抖*/if(up)press_down = 1;/当按键没有按下,置标志位为1.if(!up & (press_down = 1) press_down = 0; /当按键按下,置标志位为0.ev_press = 1;at91_set_gpio_value(button_irq0.pin,

14、 1);key_valuesbutton_irq0.number = !up;tasklet_schedule(&button_tasklet);return IRQ_RETVAL(IRQ_HANDLED);static int button_open(struct inode *inode, struct file *filp)return 0;static int button_release(struct inode *inode, struct file *filp)return 0;static int button_read(struct file *filp, char _use

15、r *buff, size_t count, loff_t *offp)int ret;if(!ev_press) /当按键没有按下时，读进程挂起，知道按键按下。wait_event_interruptible(button_waitq, ev_press);ev_press = 0;ret = copy_to_user(buff, (const void *)key_values, min(sizeof(key_values), count);memset(void _user *)key_values, 0, sizeof(key_values);return ret ? -EFAULT:

16、min(sizeof(key_values), count); static struct file_operations button_fops = .owner = THIS_MODULE,.open = button_open,.release = button_release,.read = button_read,;static int irq_init(void)int err;at91_set_gpio_input(button_irq0.pin, 1);at91_set_deglitch(button_irq0.pin, 1);/将PC0设置为中断功能set_irq_type(

17、button_irq0.irq, button_irq0.irq_type);/设置中断类型at91_set_gpio_value(button_irq0.pin, 1);err = request_irq( button_irq0.irq, button_interrupt, IRQF_DISABLED, button_irq0.name, (void *)&button_irq0);/申请中断if ( err ) disable_irq(button_irq0.irq);free_irq(button_irq0.irq, (void *)&button_irq0);return -EBUS

18、Y;return 0;static int _init button_init(void)int ret, err;ret = register_chrdev_region(MKDEV(BUTTON_MAJOR, 0), 1, DEVICE_NAME);if(ret 0) printk(button init failed with %dn, ret);return ret;cdev_init(&button_cdev, &button_fops);button_cdev.owner = THIS_MODULE;button_cdev.ops = &button_fops;err = cdev

19、_add(&button_cdev, MKDEV(BUTTON_MAJOR, 0), 1);if( err0 ) printk(key add failedn);return err;irq_init();printk(key driver add success!n);return 0;static void _exit button_exit(void)cdev_del(&button_cdev);unregister_chrdev_region(MKDEV(BUTTON_MAJOR, 0), 1);disable_irq(button_irq0.irq);free_irq(button_

20、irq0.irq, (void *)&button_irq0);printk(unregister key driver!n);module_init(button_init);module_exit(button_exit);MODULE_AUTHOR(fany);MODULE_DESCRIPTION(Atmel9g20 key Driver);MODULE_LICENSE(GPL);3. 测试程序：#include #include #include #include #include #include #define DEVICE_NAME /dev/buttonint main(voi

21、d)int fd,i;int ret;int key_value1;printf(key test!n);fd = open(DEVICE_NAME, O_RDWR);if(fd 0)printf(open device %s error!n, DEVICE_NAME);elseprintf(open device success!n);while(1) ret = read(fd, key_value, 1);if( !ret ) printf(button not press!n);elseprintf(button press!n);printf(key_value %dn, key_v

22、alue);close(fd);printf(close key driver!n);return 0;4.学习总结：在linux设备驱动程序中，中断处理程序通常分为两部分：上半部和下半部。上半部处理比较紧急的的硬件操作，比如简单的读取寄存器中的状态并清除中断标志后，进行登记中断的工作。剩下的工作就由下半部来实现。对阻塞与非阻塞进程的理解，阻塞：在执行设备操作时，若不能获取设备资源则挂起，直到满足可操作的条件后再进行操作。非阻塞操作：在执行设备操作时，若不能获取设备资源则立即返回。三：总线驱动AT91SAM9G20存储器映射图(截取部分)，片选4接外设，利用总线对外设进行访问。但是在linux

23、驱动，不能对物理地址进行操作，可通过内存访问的机制实现对物理地址的访问。将一段物理地址空间映射到虚拟地址空间中，然后对虚拟地址的操作即是对物理地址的操作。3.1：总线驱动#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include atmel9g20_liu.hstruct gr_liu_info void _iomem*virtbase;void _iomem*regb

24、ase;struct resource *res;u32flags;static struct gr_liu_info liu_info;static struct cdev atmel9g20_liu_cdev;unsigned short liu_read(unsigned addr)addr &= ATMEL9G20_LIU_MASK;addr = addr 1;addr += (unsigned long)liu_info.regbase;printk(read the virtual addr is 0x%xn, addr);return readw(addr) & 0xff;/读I

25、O内存。EXPORT_SYMBOL(liu_read);int liu_write(unsigned addr, unsigned val)addr &= ATMEL9G20_LIU_MASK;addr = addr num_resources != 1) ret = -ENODEV;goto err1;/IO内存的申请liu_info.res = request_mem_region(pdev-resource0.start, pdev-resource0.end - pdev-resource0.start + 1, 9g20-liu);if (!liu_info.res) printk(

26、liu: cant get request mem region);ret = -ENOMEM;goto err1;/IO内存的映射liu_info.regbase = ioremap(pdev-resource0.start, pdev-resource0.end - pdev-resource0.start + 1);printk(request virtual addr liu_info.regbase=0x%xn,(unsigned int)liu_info.regbase);if (liu_info.regbase = NULL) printk(liu: cant get iorem

27、ap memn);ret = -ENOMEM;goto err2; dev_set_drvdata(&pdev-dev, &liu_info);printk(LIU probe done!n);return 0;err2:release_mem_region(pdev-resource0.start, pdev-resource0.end - pdev-resource0.start + 1);err1:return ret;static int liu_remove(struct platform_device *pdev)struct gr_liu_info *fi;fi = pdev-d

28、ev.driver_data;iounmap(fi-regbase);/解除映射，release_mem_region(pdev-resource0.start, pdev-resource0.end - pdev-resource0.start + 1);/释放内存fi-flags = 0x0;return 0;static struct platform_driver liu_driver = .probe = liu_probe,.remove = liu_remove,.driver = .name = 9g20-liu,.owner = THIS_MODULE,;/设置SMC寄存器s

29、tatic void cs4_init(void)at91_sys_write(AT91_MATRIX_EBICSA,at91_sys_read(AT91_MATRIX_EBICSA) | AT91_MATRIX_CS4A_SMC);/* Configure SMC CS4 */at91_sys_write(AT91_SMC_SETUP(4), AT91_SMC_NWESETUP_(2) | AT91_SMC_NCS_WRSETUP_(2) | AT91_SMC_NRDSETUP_(2) | AT91_SMC_NCS_RDSETUP_(2);at91_sys_write(AT91_SMC_PU

30、LSE(4), AT91_SMC_NWEPULSE_(12) | AT91_SMC_NCS_WRPULSE_(10) | AT91_SMC_NRDPULSE_(12) | AT91_SMC_NCS_RDPULSE_(10);at91_sys_write(AT91_SMC_CYCLE(4), AT91_SMC_NWECYCLE_(16) | AT91_SMC_NRDCYCLE_(16);at91_sys_write(AT91_SMC_MODE(4), AT91_SMC_READMODE | AT91_SMC_WRITEMODE | AT91_SMC_DBW_16 | AT91_SMC_EXNWM

31、ODE_DISABLE | AT91_SMC_TDF_(3);at91_sys_write(AT91_PMC_PCER, 1 AT91SAM9260_ID_PIOC);/* Enable CS4 */ at91_set_A_periph(AT91_PIN_PC8, 1); printk(*at91sam9g20ek_ebibus_cs4_init*n);static int _init atmel9g20_liu_init(void)int ret,err;ret = register_chrdev_region(MKDEV(LIU_MAJOR, 0), 1, /dev/liu);if( re

32、t 0) printk(LIU init_module failed with %dn, ret);return ret;cdev_init(&atmel9g20_liu_cdev, &atmel9g20_liu_fops);atmel9g20_liu_cdev.owner = THIS_MODULE;atmel9g20_liu_cdev.ops = &atmel9g20_liu_fops;err = cdev_add(&atmel9g20_liu_cdev, MKDEV(LIU_MAJOR, 0), 1);if( err0 ) printk(liu add failedn);return e

33、rr;cs4_init();return platform_driver_register(&liu_driver);/注册平台设备。static void _exit atmel9g20_liu_cleanup(void)printk(atmel 9g20 liu exitn);cdev_del(&atmel9g20_liu_cdev);unregister_chrdev_region(MKDEV(LIU_MAJOR, 0), 1);platform_driver_unregister(&liu_driver);module_init(atmel9g20_liu_init);module_e

34、xit(atmel9g20_liu_cleanup);MODULE_AUTHOR(fany);MODULE_DESCRIPTION(Atmel9g20 liu Driver);MODULE_LICENSE(GPL);并在/arch/arm/mach-at91/board-sam9g20ek.c中初始化#define GR_LIU_BASE 0x#define GR_LIU_SIZE 0x1000static struct resource gr_liu_resource = .start= GR_LIU_BASE,.end= GR_LIU_BASE + GR_LIU_SIZE - 1,.fla

35、gs= IORESOURCE_MEM,;static struct platform_device grd_liu = .name= 9g20-liu,.id= -1,.dev= .platform_data= NULL,.resource= gr_liu_resource,.num_resources= 1,;static void _init at91_add_device_liu(void) platform_device_register(&grd_liu); printk(*at91_add_device_liu*n);static void _init ek_board_init(void).at91_add_device_liu();3.2:总线驱动测试程序：#include #include #include sys/ioc