Linux內(nèi)核裁減和驅(qū)動程序開發(fā)

Linux內(nèi)核裁減和驅(qū)動程序開發(fā)主要內(nèi)容ARMLinux環(huán)境說明Linux內(nèi)核裁減LinuxGPIO驅(qū)動編寫LinuxADC驅(qū)動編寫ARMLinux環(huán)境說明Linux內(nèi)核：linux-.tar.bz2Linux根文件系統(tǒng)：rootfs.tar.bz2Linux開發(fā)環(huán)境及編譯器：PACKAGES.ISOarm-linux-gcc-4.4.1.tar.bz2Linux內(nèi)核裁減

-如何裁減Makemenuconfig選擇那些需要用的內(nèi)核模塊和驅(qū)動模塊Linux內(nèi)核裁減

-建立交叉編譯環(huán)境獲取交叉編譯鏈：/sgpp/lite/arm/portal/subscription3057目前最新為：SourceryG++Lite2009q3-67forARMGNU/Linux調(diào)整編譯鏈：默認選擇的庫是ARMv5TE-Little-Endian,Soft-Float,GLIBC,但是我們需要的是ARMv4T的庫，因此可使用選項-march=armv4t指定libc/armv4t/lib添加libjpeg,libpng,libz和libuuid(e2fprogs)庫到對應(yīng)的libc/armv46/lib和libc/usr/include里。以支持Qtopia的編譯。Linux內(nèi)核裁減

-獲取內(nèi)核源碼查看最新版本Linux內(nèi)核更新信息：/Linux_2_6_32

下載對應(yīng)內(nèi)核代碼:/pub/linux/kernel/v2.6/linux-.tar.bz2

Linux內(nèi)核裁減

-定制Linux內(nèi)核修改Makefile來支持ARM平臺，將”ARCH?=(SUBARCH)”和”CROSS_COMPILE?=“改為”ARCH=arm”和”CROSS_COMPILE=arm-linux-”。makemenuconfig加載默認配置單文件arch/arm/configs/mini2440_defconfig添加自己的信息：Generalsetup->Localversion->QiuShi其中Mini2440的機器碼為：1999.在arch/arm/tools/mach-types。將s3c2440對應(yīng)機器碼修改為1999修改NAND分區(qū):arch/arm/mach-s3c2440/mach-smdk2440.cLinux內(nèi)核裁減

-定制Linux內(nèi)核添加yaffs文件系統(tǒng)支持：注意對于128MB大容量NAND需要頁大小來支持制作文件系統(tǒng)鏡像文件工具mkyaffs2image需要支持128MBLinuxGPIO驅(qū)動編寫

-撥碼開關(guān)驅(qū)動打開內(nèi)核源碼文件\drivers\char\2440_buttons.c這是char驅(qū)動是控制gpio的驅(qū)動LinuxGPIO驅(qū)動編寫定義驅(qū)動名稱#defineDEVICE_NAME"buttons"動態(tài)創(chuàng)建設(shè)備節(jié)點/dev/buttons應(yīng)用程序使用設(shè)備Open(“/dev/buttons”,O_RDWR)LinuxGPIO驅(qū)動編寫staticstructbutton_irq_descbutton_irqs[]={{IRQ_EINT0,S3C2410_GPF(0),S3C2410_GPF0_EINT0,0,"KEY0"},{IRQ_EINT1,S3C2410_GPF(1),S3C2410_GPF1_EINT1,1,"KEY1"},{IRQ_EINT2,S3C2410_GPF(2),S3C2410_GPF2_EINT2,2,"KEY2"},{IRQ_EINT3,S3C2410_GPF(3),S3C2410_GPF3_EINT3,3,"KEY3"},{IRQ_EINT4,S3C2410_GPF(4),S3C2410_GPF4_EINT4,4,"KEY4"},{IRQ_EINT5,S3C2410_GPF(5),S3C2410_GPF5_EINT5,5,"KEY5"},{IRQ_EINT6,S3C2410_GPF(6),S3C2410_GPF6_EINT6,6,"KEY6"},{IRQ_EINT8,S3C2410_GPG(0),S3C2410_GPG0_EINT8,7,"KEY7"},{IRQ_EINT9,S3C2410_GPG(1),S3C2410_GPG1_EINT9,8,"KEY8"},};LinuxGPIO驅(qū)動編寫staticstruct

file_operations

dev_fops={.owner=THIS_MODULE,.open=s3c24xx_buttons_open,.release=s3c24xx_buttons_close,.read=s3c24xx_buttons_read,.poll=s3c24xx_buttons_poll,.ioctl=s3c2410_buttons_ioctl,};file_operations設(shè)備使用方法這個結(jié)構(gòu)的每一個成員都對應(yīng)著一個系統(tǒng)調(diào)用。讀取file_operation中相應(yīng)的函數(shù)指針，接著把控制權(quán)轉(zhuǎn)交給函數(shù)，從而完成了Linux設(shè)備驅(qū)動程序的工作。int(*open)(structinode*,structfile*);ssize_t(*read)(structfile*,char__user*,size_t,loff_t*);ssize_t(*write)(structfile*,constchar__user*,size_t,loff_t*);int(*ioctl)(structinode*,structfile*,unsignedint,unsignedlong);LinuxGPIO驅(qū)動編寫staticstructmiscdevicemisc={ .minor=MISC_DYNAMIC_MINOR, .name=DEVICE_NAME, .fops=&dev_fops,};LinuxGPIO驅(qū)動編寫staticint__initdev_init(void){ intret; ret=misc_register(&misc); printk(DEVICE_NAME"\tinitialized\n"); returnret;}LinuxGPIO驅(qū)動編寫staticvoid__exitdev_exit(void){ misc_deregister(&misc);}LinuxGPIO驅(qū)動編寫module_init(dev_init);module_exit(dev_exit);MODULE_LICENSE("GPL");MODULE_AUTHOR("QiuShiInc.");LinuxGPIO驅(qū)動編寫driver/char/Kconfig告訴makemenuconfig如何裁減LinuxGPIO驅(qū)動編寫driver/char/Makefile告訴編譯器如何編譯LinuxGPIO驅(qū)動編譯回到內(nèi)核根目錄Makemenuconfig退出保存makemodules在drivers/char/目錄下生成mini2440_buttons.ko復(fù)制到開發(fā)版中LinuxGPIO驅(qū)動加載在開發(fā)中使用：insmodmini2440_buttons.ko加載驅(qū)動使用：rmmodmini2440_buttons.ko卸載驅(qū)動LinuxGPIO驅(qū)動使用#include<stdio.h>#include<stdlib.h>#include<unistd.h>#include<sys/ioctl.h>#include<sys/types.h>#include<sys/stat.h>#include<fcntl.h>#include<sys/select.h>#include<sys/time.h>#include<errno.h>LinuxGPIO驅(qū)動使用int

main(void){

int

buttons_fd; charbuttons[9]={'0','0','0','0','0','0','0','0','0'};

buttons_fd=open("/dev/buttons",0); if(buttons_fd<0){

perror("opendevicebuttons"); exit(1); } for(;;){ charcurrent_buttons[9];

int

count_of_changed_key;

inti; if(read(buttons_fd,current_buttons,sizeof

current_buttons)!=sizeof

current_buttons){

perror("readbuttons:"); exit(1); }

LinuxGPIO驅(qū)動使用

for(i=0,count_of_changed_key=0;i<sizeofbuttons/sizeofbuttons[0];i++){ if(buttons[i]!=current_buttons[i]){

buttons[i]=current_buttons[i];

printf("%skey%dis%s",count_of_changed_key?",":"",i+1,b