ARM字符驅(qū)動實例

字符驅(qū)動實例本實驗電路圖4個LED指示燈的接口電路驅(qū)動程序#include<linux/kernel.h>#include<linux/module.h>#include<linux/init.h>#include<linux/fs.h>#include<linux/cdev.h>#include<linux/ioport.h>#include<asm-arm/io.h>#include<linux/ioctl.h>#include<linux/interrupt.h>#include<linux/delay.h>#include<linux/timer.h>#include<asm/irq.h>#include<linux/param.h>#include<linux/sched.h>#include<linux/errno.h>#include<asm/signal.h>定義request_mem_region所需的頭文件定義I/O讀寫,I/O內(nèi)存讀寫所需的頭文件定義ioctl函數(shù)所需的頭文件定義ioctl函數(shù)所需的頭文件定義延遲與定時器函數(shù)所需的頭文件定義中斷函數(shù)所需的頭文件#defineCDRIVER_NAME"LED_chrdev"#defineGPFCON(0X56000050)#defineGPFDAT(0X56000054)#defineGPFUP(0X56000058)staticvoid*gpfcon;staticvoid*gpfdat;staticvoid*gpfup;intCDRIVER_MAJOR=0;intCDRIVER_MINOR=0;intcount=1;定義物理地址定義映射后的虛擬地址指針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,};staticint__initLED_init(void){……if(!request_mem_region(GPFCON,12,CDRIVER_NAME)){ printk(KERN_ERR"LED: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_ERR"LED:ioremapfailed\n");

iounmap(gpfcon); return-EINVAL; }申請I/O內(nèi)存I/O內(nèi)存映射若映射不成功,釋放

if(!gpfdat){ printk(KERN_ERR"LED:ioremapfailed\n");

iounmap(gpfdat); return-EINVAL; } if(!gpfup){ printk(KERN_ERR"LED:ioremapfailed\n");

iounmap(gpfup); return-EINVAL; } return0;}若映射不成功,釋放若映射不成功,釋放intLED_open(structinode*inode,structfile*filp){ printk("LEDDeviceisopened\n"); writel((readl(gpfcon)&(1<<14)),gpfcon); writel((readl(gpfup)&(1<<7)),gpfup); writel((readl(gpfdat)&(0<<7)),gpfdat); ssleep(1);writel((readl(gpfdat)&(1<<7)),gpfdat); ssleep(1);writel((readl(gpfdat)&(0<<7)),gpfdat); try_module_get(THIS_MODULE); return0;}設為輸出端口上拉禁止輸出低電平,燈亮輸出高電平,燈滅/*Release*/intLED_release(structinode*inode,structfile*filp){ printk("LEDDeciceisreleased!\n"); writel((readl(gpfcon)&(0<<14)),4); writel((readl(gpfup)&(1<<7)),4); writel((readl(gpfdat)&(0<<7)),4); module_put(THIS_MODULE); return0;}staticvoid__exitLED_exit(void) {printk("UnloadingLED_cdevnow...\n");

iounmap(gpfcon); iounmap(gpfdat); iounmap(gpfup); cdev_del(LED_cdev); unregister_chrdev_region(LED_dev,count); }釋放內(nèi)存makefileifneq($(KERNELRELEASE),)obj-m:=LED_chrdev.oelsePWD:=$(shellpwd)default:$(MAKE)-C$(KERNELDIR)M=$(PWD)endif最終生成LED_chrdev.ko的可執(zhí)行文件件應用程序#include<stdio.h>#include<stdlib.h>#include<fcntl.h>#include<errno.h>#include<unistd.h>#include<linux/delay.h>#include<sys/ioctl.h>#defineDEVICE_GPIOTEST"/dev/LED_chrdev"intmain(intargc,char*argv[]){intfd;fd=open(DEVICE_GPIOTEST,O_RDONLY);提供對文件控控制的函數(shù)open等提供對I/O控制的函數(shù)數(shù)提供錯誤號errno的的定義，用于于錯誤處理linux/unix的的系統(tǒng)調(diào)用，，包含了許多多系統(tǒng)服務的的函數(shù)原型,例如read,write等函函數(shù)。if(fd<0){perror("cannotopendevice");exit(1);}close(fd);return0;}makefileTEST_LED:TEST_LED.o$(LD)-rTEST_LED.o-oTEST_LEDTEST_LED.o:TEST_LED.c$(CC)-O2-Wall-I$(INCLUDE)-L$(LIB)-cTEST_LED.c-oTEST_LED.o最終生成TEST_LED的可執(zhí)行行文件將驅(qū)動程序編編譯進內(nèi)核在超級終端下下將驅(qū)動程序序LED_chrdev.ko和應用程序TEST_LED下載到到/tmp路徑下執(zhí)行Chmod755LED_chrdev.koChmod755TEST_LEDInsmodLED_chrdev.ko./TEST_LED觀察燈的情況況!將驅(qū)動程序編編譯進內(nèi)核一.將驅(qū)動程程序LED_chrdev.c放在相應的目目錄下,比如如對于字符設設備,就放置置在fs2410/drivers/char/;二.修改drivers/…/Makefile文件三.修改drivers/…/Kconfig配置文件四.重新編譯譯內(nèi)核,下載載將驅(qū)動程序放放在相應的目目錄下修改drivers/char/Makefile修改drivers/char/Makefile修改drivers/char/Kconfig這些將出現(xiàn)在在內(nèi)核的編譯譯配置中簡化我們的設設計對I/O端口口定義的簡化化,加入頭文文件#include<asm/arch/regs-gpio.h>對I/O端口口操作的簡化化,加入頭文文件#include<asm/arch/hardware.h>#include<asm/arch/regs-gpio.h>#include<asm/arch/regs-gpio.h>I/O端口不不同功能的定定義對特殊功能寄寄存器的定義義#include<asm/arch/hardware.h>在<asm/arch/hardware.h>中包含了了對I/O端口口操作的函數(shù)數(shù)externvoids3c2410_gpio_cfgpin(unsignedintpin,unsignedintfunction);externvoids3c2410_gpio_pullup(unsignedintpin,unsignedintto);externvoids3c2410_gpio_setpin(unsignedintpin,unsignedintto);externunsignedints3c2410_gpio_getpin(unsignedintpin);函數(shù)在arch/arm/mach-s3c2410/gpio.c中定義/*s3c2410_gpio_cfgpin:設定定特定端口的的功能*eg:*s3c2410_gpio_cfgpin(S3C2410_GPA0,S3C2410_GPA0_ADDR0);*s3c2410_gpio_cfgpin(S3C2410_GPF7,S3C2410_GPF7_OUTP);*/將GPF7設設置成輸出端端口s3c2410_gpio_cfgpinvoids3c2410_gpio_cfgpin(unsignedintpin,unsignedintfunction){staticvoid*base;unsignedlongmask;unsignedlongcon;unsignedlongflags;base=ioremap_nocache(S3C2410_GPIO_PA_BASE(pin),0x0000004);if(pin<S3C2410_GPIO_BANKB){mask=1<<S3C2410_GPIO_OFFSET(pin);}else{mask=3<<S3C2410_GPIO_OFFSET(pin)*2;}local_irq_save(flags);con=__raw_readl(base+0x00);con&=~mask;con|=function;__raw_writel(con,base+0x00);local_irq_restore(flags);}將端口對應的的GPnCON寄存器進進行I/O內(nèi)內(nèi)存映射根據(jù)相應的功功能對GPnCON寄存存器的對應位位寫入相應的的值externvoids3c2410_gpio_pullup(unsignedintpin,unsignedintto);/*s3c2410_gpio_pullup**設置特定定端口的上拉拉**to=1=>disablethepull-up*0=>enablethepull-up**例子:**s3c2410_gpio_pullup(S3C2410_GPB0,0);*s3c2410_gpio_pullup(S3C2410_GPF7,1);*/s3c2410_gpio_getpinunsignedints3c2410_gpio_getpin(unsignedintpin);**設置特定輸入入端口的值**返返回非0=>高電平平*0=>低電平平**例子:**s3c2410_gpio_getpin(S3C2410_GPB0);*s3c2410_gpio_getpin(S3C2410_GPE8);*/s3c2410_gpio_getpinunsignedints3c2410_gpio_getpin(unsignedintpin){staticvoid*data;unsignedlongoffs=S3C2410_GPIO_OFFSET(pin);data=ioremap_nocache(S3C2410_GPIO_PA_BASE(pin)+0x04,0x0000004);return__raw_readl(data)&(1<<offs);}將端口對應的的GPnDAT寄存器進進行I/O內(nèi)內(nèi)存映射讀入GPnDAT寄存器器中對應位的的值s3c2410_gpio_setpinexternvoids3c2410_gpio_setpin(unsignedintpin,unsignedintto);/**設置特定定輸出端口的的高/低電平平**to=1=>高電平平*0=>低電平平**例子:**s3c2410_gpio_setpin(S3C2410_GPB0,0);*s3c2410_gpio_setpin(S3C2410_GPF7,0);*/對驅(qū)動程序的的修改……#include<asm/arch/regs-gpio.h>#include<asm/arch/hardware.h>對I/O端口口定義的頭文文件對I/O端口口操作的頭文文件staticint__initLED_init(void){……s3c2410_gpio_cfgpin(S3C2410_GPF7,S3C2410_GPF7_OUTP);s3c2410_gpio_pullup(S3C2410_GPF7,1);s3c2410_gpio_setpin(S3C2410_GPF7,0);return-EINVAL;}intLED_open(structinode*inode,structfile*filp){printk("LEDDeviceisopened\n");s3c2410_gpio_setpin(S3C2410_GPF7,0);ssleep(1);s3c2410_gpio_setpin(S3C2410_GPF7,1);ssleep(1);s3c2410_gpio_setpin(S3C2410_GPF7,0);try_module_get(THIS_MODULE);return0;}/*Release*/intLED_release(structinode*inode,structfile*filp){printk("LEDDeciceisreleased!\n");s3c2410_gpio_cfgpin(S3C2410_GPF7,S3C2410_GPF7_INP);s3c2410_gpio_pullup(S3C2410_GPF7,0);s3c2410_gpio_setpin(S3C2410_GPF7,1);module_put(THIS_MODULE);return0;}中斷驅(qū)動程程序的簡化化……#include<asm/arch/irq.h>#include<asm/arch/regs-irq.h>對各個中斷斷號的定義義對中斷寄存存器定義的的頭文件asm-arm/arch-s3c2410/irq.hIrq：表示所要要申請的中中斷號；中斷號在include/asm-arm/arch-s3c2410/irq.h中定義義asm-arm/arch-s3c2410/irq.h#include<asm/arch/regs-irq.h><arch/arm/math-s3c2410/irq.c>在<arch/arm/math-s3c2410/irq.c>中定義義有中斷操操作的相關關函數(shù),可可以通過extern語句句加入這些些函數(shù)在<arch/arm/math-s3c2410/irq.c>中定義義有中斷操操作的相關關函數(shù)s3c_irq_mask(unsignedintirqno)//中斷斷屏蔽s3c_irq_unmask(unsignedintirqno)//中斷斷使能s3c_irq_ack(unsignedintirqno)//清中中斷掛起void__inits3c2410_init_irq(void)//中中斷初初始化s3c_irqext_mask(unsignedintirqno)//外部中斷斷屏蔽s3c_irqext_ack(unsignedintirqno)//清清外部中斷斷掛起s3c_irqext_unmask(unsignedintirqno)//外部部中斷使能能<arch/arm/math-s3c2410/irq.c>函數(shù)：s3c_irq_mask(unsignedintirqno)參數(shù)：irqno表示中斷斷號作用:屏屏蔽特定定中斷例子：s3c_irq_mask（（IRQ_EINT0）s3c_irq_mask(unsignedintirqno){unsignedlongma