ARM字符驱动实例

1TMTHEARCHITECTUREFORTHEDIGITALWORLD字符驱动实例2TM2ARM及Thumb指令集本实验电路图4个LED指示灯的接口电路3TM3ARM及Thumb指令集驱动程序#includelinux/kernel.h#includelinux/module.h#includelinux/init.h#includelinux/fs.h#includelinux/cdev.h#includelinux/ioport.h#includeasm-arm/io.h#includelinux/ioctl.h#includelinux/interrupt.h#includelinux/delay.h#includelinux/timer.h#includeasm/irq.h#includelinux/param.h#includelinux/sched.h#includelinux/errno.h#includeasm/signal.h定义request_mem_region所需的头文件定义I/O读写,I/O内存读写所需的头文件定义ioctl函数所需的头文件定义ioctl函数所需的头文件定义延迟与定时器函数所需的头文件定义中断函数所需的头文件4TM4ARM及Thumb指令集#defineCDRIVER_NAMELED_chrdev#defineGPFCON(0X56000050)#defineGPFDAT(0X56000054)#defineGPFUP(0X56000058)staticvoid*gpfcon;staticvoid*gpfdat;staticvoid*gpfup;intCDRIVER_MAJOR=0;intCDRIVER_MINOR=0;intcount=1;定义物理地址定义映射后的虚拟地址指针5TM5ARM及Thumb指令集loff_tLED_llseek(structfile*filp,loff_toff,intwhence);intLED_ioctl(structinode*inode,structfile*filp,unsignedintcmd,unsignedlongarg);intLED_open(structinode*inode,structfile*filp);intLED_release(structinode*inode,structfile*filp);externstructfile_operationsLED_fops;structcdev*LED_cdev;dev_tLED_dev;structfile_operationsLED_fops={.owner=THIS_MODULE,.llseek=LED_llseek,.open=LED_open,.release=LED_release,};6TM6ARM及Thumb指令集staticint__initLED_init(void){……if(!request_mem_region(GPFCON,12,CDRIVER_NAME)){printk(KERN_ERRLED:io%Xisnotfree.\n,GPFCON);return-EBUSY;}gpfcon=ioremap_nocache(GPFCON,4);gpfdat=ioremap_nocache(GPFDAT,4);gpfup=ioremap_nocache(GPFUP,4);if(!gpfcon){printk(KERN_ERRLED:ioremapfailed\n);iounmap(gpfcon);return-EINVAL;}申请I/O内存I/O内存映射若映射不成功,释放7TM7ARM及Thumb指令集if(!gpfdat){printk(KERN_ERRLED:ioremapfailed\n);iounmap(gpfdat);return-EINVAL;}if(!gpfup){printk(KERN_ERRLED:ioremapfailed\n);iounmap(gpfup);return-EINVAL;}return0;}若映射不成功,释放若映射不成功,释放8TM8ARM及Thumb指令集intLED_open(structinode*inode,structfile*filp){printk(LEDDeviceisopened\n);writel((readl(gpfcon)&(114)),gpfcon);writel((readl(gpfup)&(17)),gpfup);writel((readl(gpfdat)&(07)),gpfdat);ssleep(1);writel((readl(gpfdat)&(17)),gpfdat);ssleep(1);writel((readl(gpfdat)&(07)),gpfdat);try_module_get(THIS_MODULE);return0;}设为输出端口上拉禁止输出低电平,灯亮输出高电平,灯灭9TM9ARM及Thumb指令集/*Release*/intLED_release(structinode*inode,structfile*filp){printk(LEDDeciceisreleased!\n);writel((readl(gpfcon)&(014)),4);writel((readl(gpfup)&(17)),4);writel((readl(gpfdat)&(07)),4);module_put(THIS_MODULE);return0;}10TM10ARM及Thumb指令集staticvoid__exitLED_exit(void){printk(UnloadingLED_cdevnow...\n);iounmap(gpfcon);iounmap(gpfdat);iounmap(gpfup);cdev_del(LED_cdev);unregister_chrdev_region(LED_dev,count);}释放内存11TM11ARM及Thumb指令集makefileifneq($(KERNELRELEASE),)obj-m:=LED_chrdev.oelseKERNELDIR?=/usr/src/fs2410_2.6.8/PWD:=$(shellpwd)default:$(MAKE)-C$(KERNELDIR)M=$(PWD)endif最终生成LED_chrdev.ko的可执行文件12TM12ARM及Thumb指令集应用程序#includestdio.h#includestdlib.h#includefcntl.h#includeerrno.h#includeunistd.h#includelinux/delay.h#includesys/ioctl.h#defineDEVICE_GPIOTEST/dev/LED_chrdevintmain(intargc,char*argv[]){intfd;fd=open(DEVICE_GPIOTEST,O_RDONLY);提供对文件控制的函数open等提供对I/O控制的函数提供错误号errno的定义，用于错误处理linux/unix的系统调用，包含了许多系统服务的函数原型,例如read,write等函数。13TM13ARM及Thumb指令集if(fd0){perror(cannotopendevice);exit(1);}close(fd);return0;}14TM14ARM及Thumb指令集makefileCC=/usr/local/3.3.2/bin/arm-linux-gccLD=/usr/local/3.3.2/bin/arm-linux-ldINCLUDE=/usr/local/3.3.2/include/LIB=/usr/local/3.3.2/lib/TEST_LED:TEST_LED.o$(LD)-rTEST_LED.o-oTEST_LEDTEST_LED.o:TEST_LED.c$(CC)-O2-Wall-I$(INCLUDE)-L$(LIB)-cTEST_LED.c-oTEST_LED.o最终生成TEST_LED的可执行文件15TM15ARM及Thumb指令集将驱动程序编译进内核在超级终端下将驱动程序LED_chrdev.ko和应用程序TEST_LED下载到/tmp路径下执行Chmod755LED_chrdev.koChmod755TEST_LEDInsmodLED_chrdev.ko./TEST_LED观察灯的情况!16TM16ARM及Thumb指令集将驱动程序编译进内核一.将驱动程序LED_chrdev.c放在相应的目录下,比如对于字符设备,就放置在fs2410/drivers/char/;二.修改drivers/…/Makefile文件三.修改drivers/…/Kconfig配置文件四.重新编译内核,下载17TM17ARM及Thumb指令集将驱动程序放在相应的目录下18TM18ARM及Thumb指令集修改drivers/char/Makefile19TM19ARM及Thumb指令集修改drivers/char/Makefile20TM20ARM及Thumb指令集修改drivers/char/Kconfig这些将出现在内核的编译配置中21TM21ARM及Thumb指令集简化我们的设计对I/O端口定义的简化,加入头文件#includeasm/arch/regs-gpio.h对I/O端口操作的简化,加入头文件#includeasm/arch/hardware.h22TM22ARM及Thumb指令集#includeasm/arch/regs-gpio.h23TM23ARM及Thumb指令集#includeasm/arch/regs-gpio.hI/O端口不同功能的定义对特殊功能寄存器的定义24TM24ARM及Thumb指令集#includeasm/arch/hardware.h在asm/arch/hardware.h中包含了对I/O端口操作的函数externvoids3c2410_gpio_cfgpin(unsignedintpin,unsignedintfunction);externvoids3c2410_gpio_pullup(unsignedintpin,unsignedintto);externvoids3c2410_gpio_setpin(unsignedintpin,unsignedintto);externunsignedints3c2410_gpio_getpin(unsignedintpin);函数在arch/arm/mach-s3c2410/gpio.c中定义25TM25ARM及Thumb指令集/*s3c2410_gpio_cfgpin:设定特定端口的功能*eg:*s3c2410_gpio_cfgpin(S3C2410_GPA0,S3C2410_GPA0_ADDR0);*s3c2410_gpio_cfgpin(S3C2410_GPF7,S3C2410_GPF7_OUTP);*/将GPF7设置成输出端口26TM26ARM及Thumb指令集s3c2410_gpio_cfgpinvoids3c2410_gpio_cfgpin(unsignedintpin,unsignedintf