1、E04_c基於軟硬整合觀點(diǎn)從框架看HAL和Linux驅(qū)動(dòng)開(kāi)發(fā)( c)By 高煥堂基於軟硬整合觀點(diǎn)3、活用工廠EIT造形創(chuàng)建對(duì)象&設(shè)定函數(shù)指針撰寫(xiě)函數(shù)的實(shí)現(xiàn)代碼file_operations的對(duì)象*open()*read()其它data*commonsemadder_file的對(duì)象/ 函數(shù)的實(shí)現(xiàn)代碼open() / .read() / .其它擴(kuò)充及撰寫(xiě)sturc t mo due 的代碼工廠EITNew & Initialization函數(shù)代碼(起始設(shè)定)撰寫(xiě)函數(shù)的實(shí)現(xiàn)代碼創(chuàng)建對(duì)象創(chuàng)建對(duì)象&設(shè)定函數(shù)指針函數(shù)代碼(起始設(shè)定)撰寫(xiě)函數(shù)的實(shí)現(xiàn)代碼創(chuàng)建對(duì)象創(chuàng)建對(duì)象&設(shè)定函數(shù)指針 add_module子類(lèi)

2、必須實(shí)作module_init()和module_exit()函數(shù)。/*adder_module*/#define ADD_MAJOR48#define ADD_MINOR0 struct cdev add_device; int add_mod_init(void) int result;dev_t devno = MKDEV(ADD_MAJOR, ADD_MINOR); result = register_chrdev_region(devno, 1, androidin); if(result 0) return result;init_MUTEX(&adder.sem); cdev_i

3、nit(&add_device, &fop); my_cdev.owner = THIS_MODULE;fail:result = cdev_add(&add_device, devno, 1); if(result)goto fail;return 0;add_cleanup(); return result;void add_mod_cleanup(void) dev_t devno = MKDEV(ADD_MAJOR, ADD_MINOR); cdev_del(&add_device); unregister_chrdev_region(devno, 1);module_init(add

4、_mod_init); module_exit(add_mod_cleanup); MODULE_LICENSE(GPL); module_init()函數(shù)負(fù)責(zé)初期化(initialization)動(dòng)作。首先呼叫cdev類(lèi)別的cdev_init()函數(shù)來(lái)進(jìn)行初始化動(dòng)作，如下指令：cdev_init(add_device, &fop); 這讓add_device對(duì)象指向fop對(duì)象。此外， 也讓Linux所誕生的struct file對(duì)象(內(nèi)含f_op指針)指向fop對(duì)象。 接著，執(zhí)行如下指令：cdev_add(&add_device, devno, 1); 這呼叫cdev_add()函數(shù)把cde

5、v 對(duì)象指針存入到Linux內(nèi)核的cdev_map里。讓Linux內(nèi)核可以透過(guò)file_operations接口而呼叫到cdev類(lèi)里的函數(shù)。 對(duì)系統(tǒng)而言，當(dāng)設(shè)備驅(qū)動(dòng)成功調(diào)用了cdev_add()之后，就意味著一個(gè)設(shè)備對(duì)象 已經(jīng)加入到了系統(tǒng)，讓系統(tǒng)就可以找到它。對(duì)用戶(hù)態(tài)的應(yīng)用程序而言，調(diào)用cdev_add() 之后，就已經(jīng)可以通過(guò)System Call呼叫驅(qū)動(dòng)程序了。 現(xiàn)在已經(jīng)將adder_file和adder_module撰寫(xiě)完畢了。經(jīng)過(guò)編譯&連結(jié)成為*.ko模塊之后，就能將此驅(qū)動(dòng)模塊掛載到Linux內(nèi)核里了。file_operations的對(duì)象*open()*read()其它data*com

6、monsemadder_file的對(duì)象/ 函數(shù)的實(shí)現(xiàn)代碼open() / .read() / .其它函數(shù)代碼(起始設(shè)定)撰寫(xiě)函數(shù)的實(shí)現(xiàn)代碼創(chuàng)建對(duì)象創(chuàng)建對(duì)象&設(shè)定函數(shù)指針 這個(gè)對(duì)象是以靜態(tài)(static)方式宣告的。struct cdev add_device;其它*f_op其它file的對(duì)象*open()*read()cdev的對(duì)象/ 函數(shù)的實(shí)現(xiàn)代碼open() read() 其它/ ./ .其它*ops其它file_operations的對(duì)象adder_file的對(duì)象data*commonsemcdev_init(&add_device, &fop); 這讓add_device對(duì)象指向fop對(duì)象。此外， 也讓Linux所誕生的strut file對(duì)象(內(nèi)含f_op 指針)指向fop對(duì)象。 其它*f_op其它file的對(duì)象file_operations的對(duì)象*open()*read()其它其它*opsdata*commonsemadder_file的對(duì)象cdev的對(duì)象/ 函數(shù)的實(shí)現(xiàn)代碼open() / .read() / .其它AppLinux (框架)*f_op其它data*commonfile的對(duì)象adder_file的對(duì)象cdev的對(duì)象*open()*read()其它file_operations的對(duì)象*ops/ 函數(shù)的實(shí)現(xiàn)代碼其