linux .ko的编译与测试

以【tiny210 按键实验为例】

准备：
内核：Linux-3.0.8 （开发板的运行内核）
平台：Fedora14

例子：
建立空文件夹（ko文件），在里面添加需要制成的文件：
内核源码：my_button.c
Makefile文件：Makefile
测试文件：buttons_test.c

编辑内核源码：my_button.c 【采用按键驱动（异步通知机制）】 ———部分代码
my_button.c：

#define DEVICE_NAME     "buttons_test"static struct fasync_struct *button_async;/*  * 按键中断出发确定按键值 *在中断处理程序中调用kill_fasync函数  */  static irqreturn_t button_interrupt(int irq, void *dev_id){    struct button_desc *bdata = (struct button_desc *)dev_id;    mod_timer(&bdata->timer, jiffies + msecs_to_jiffies(40));    //发送信号SIGIO信号给fasync_struct 结构体所描述的PID，触发应用程序的SIGIO信号处理函数      kill_fasync(&button_async, SIGIO, POLL_IN);      return IRQ_HANDLED;}/**驱动fasync接口实现*/static int mini210_buttons_fasync (int fd, struct file *filp, int on)  {      printk("driver: fifth_drv_fasync\n");      //初始化/释放 fasync_struct 结构体 (fasync_struct->fa_file->f_owner->pid)      return fasync_helper(fd, filp, on, &button_async);}static struct file_operations dev_fops = {    .owner      = THIS_MODULE,    .open       = mini210_buttons_open,    .release    = mini210_buttons_close,     .read       = mini210_buttons_read,    .poll       = mini210_buttons_poll,    .fasync     = mini210_buttons_fasync,};

异步通知机制：
在Linux下，异步通知类似于信号机制，内核和应用程序之间采用通知方法来告知是否发生对应的事件，并进一步采取相应的动作，当产生按键动作时，发生中断，由驱动程序使用kill_fasync函数告知应用程序，而应用程序需要向内核提供PID，然后就可以工作了。

Makefile文件：Makefile
内容如下：

obj-m := my_button.o                   #要生成的模块名     my_button-objs:= module        #生成这个模块名所需要的目标文件#KDIR := /lib/modules/`uname -r`/build      #Fedora14 默认的内核目录KDIR := /opt/FriendlyARM/tiny210/android/linux-3.0.8    #自定义内核目录（tiny210运行内核）PWD := $(shell pwd)MAKE:=make  default:    $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules  clean:    $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) clean

说明：
obj-m = *.o
obj-y = *.o
上面两者的区别在于，前者才会生成ko文件，后者只是代码编译进内核，并不生成ko文件。
生成KO文件，分两种情况：单个.c文件和多个.c文件
单个.c文件：
kernel配置文件中定义
CONFIG_RUNYEE_CAMVIB=m
注意上面的m，表示作为一个模块进行编译，最后在MAKEFILE中需要用到的编译开关。
然后再相应的源码目录中的MAKEFILE中添加如下语句：
obj-$(CONFIG_RUNYEE_CAMVIB) := camvib.o

上面的一行的作用就是编译camvib.c的源文件，同时会生成相应的camvib.ko文件，和编译生成的camvib.o在同一目录
最后就是insmod动作了：
insmod /system/lib/modules/camvib.ko
2.多个.c文件生成ko文件
kernel配置文件中定义
CONFIG_TOUCHSCREEN_FOCALTECH=m
注意上面的m，表示作为一个模块进行编译，最后在MAKEFILE中需要用到的编译开关。
然后再相应的源码目录中的MAKEFILE中添加如下语句：
obj-$(CONFIG_TOUCHSCREEN_FOCALTECH) += focaltech_ts.o
focaltech_ts-objs := focaltech.o
focaltech_ts-objs += focaltech_ctl.o
focaltech_ts-objs += focaltech_ex_fun.o
上面的意思就是编译生成ko文件需要三个.c文件【focaltech.c focaltech_ctl.c focaltech_ex_fun.c】,最后
生成名为focaltech_ts的ko文件，注意ko文件名一定不能为focaltech。那么在obj-m和lpc-objs中都含有focaltech.o，
对make来讲会产生循环和混淆，因此也不能这样书写
最后就是insmod动作了：
insmod /system/lib/modules/focaltech_ts.ko
注意事项：
1、内核目录
2、Makefile中obj-m:=my_button.o 这个和源文件my_button.c要对应
3、my_button-objs:=module 这个my_button也是和my_button.c对应的
如果源文件为your.c
这两句话就应该改为obj-m:=your.o
your-objs:=module
4、查看输出的时候 用dmesg输出信息太多，可以用grep过滤一下
dmesg | grep “buttons_test”

测试文件：buttons_test.c
核心代码：
//在应用程序中捕捉SIGIO信号（由驱动程序发送）
signal(SIGIO, my_signal_fun);
//将当前进程PID设置为fd文件所对应驱动程序将要发送SIGIO,SIGUSR信号进程PID
fcntl(buttons_fd, F_SETOWN, getpid());
//获取fd的打开方式
Oflags = fcntl(buttons_fd, F_GETFL);
//将fd的打开方式设置为FASYNC — 即 支持异步通知
//该行代码执行会触发 驱动程序中 file_operations->fasync 函数 ——fasync函数调用fasync_helper初始化一个fasync_struct结构体，该结构体描述了将要发送信号的进程PID (fasync_struct->fa_file->f_owner->pid)
fcntl(buttons_fd, F_SETFL, Oflags | FASYNC);
代码如下：

#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>#include <signal.h>int buttons_fd;int break_flg;char buttons[8] = {'0', '0', '0', '0', '0', '0', '0', '0'};//信号处理函数  void my_signal_fun(int signum)  {      char current_buttons[8];    int count_of_changed_key;    int i;    if (read(buttons_fd, current_buttons, sizeof current_buttons) != sizeof current_buttons) {        perror("read buttons:");        exit(1);    }    for (i = 0, count_of_changed_key = 0; i < sizeof buttons / sizeof buttons[0]; i++) {        if (buttons[i] != current_buttons[i]) {            buttons[i] = current_buttons[i];            printf("%skey %d is %s", count_of_changed_key? ", ": "", i+1, buttons[i] == '0' ? "0" : "1");            count_of_changed_key++;        }    }    if (count_of_changed_key) {        printf("\n");    }    if((buttons[0] == '1')&&(buttons[7]=='1'))    {        printf("key test off\n");break_flg = 1;    }}  int main(void){    int Oflags;      break_flg = 0;    //在应用程序中捕捉SIGIO信号（由驱动程序发送）      signal(SIGIO, my_signal_fun);      buttons_fd = open("/dev/buttons_test", 0);    if (buttons_fd < 0) {        perror("open device buttons");        exit(1);    }     //将当前进程PID设置为fd文件所对应驱动程序将要发送SIGIO,SIGUSR信号进程PID       fcntl(buttons_fd, F_SETOWN, getpid());      //获取fd的打开方式      Oflags = fcntl(buttons_fd, F_GETFL);   //将fd的打开方式设置为FASYNC --- 即 支持异步通知  //该行代码执行会触发 驱动程序中 file_operations->fasync 函数 ------fasync函数调用fasync_helper初始化一个fasync_struct结构体，该结构体描述了将要发送信号的进程PID (fasync_struct->fa_file->f_owner->pid)      fcntl(buttons_fd, F_SETFL, Oflags | FASYNC);          while (1)          {          sleep(1000);          if(break_flg == 1)        break;        }     close(buttons_fd);    return 0;}

完整代码：

//内核源码：/* * linux/drivers/char/mini210_buttons.c * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */#include <linux/module.h>#include <linux/kernel.h>#include <linux/fs.h>#include <linux/init.h>#include <linux/delay.h>#include <linux/sched.h>#include <linux/poll.h>#include <linux/irq.h>#include <asm/irq.h>#include <asm/io.h>#include <linux/interrupt.h>#include <asm/uaccess.h>#include <mach/hardware.h>#include <linux/platform_device.h>#include <linux/cdev.h>#include <linux/miscdevice.h>#include <mach/map.h>#include <mach/gpio.h>#include <mach/regs-clock.h>#include <mach/regs-gpio.h>#define DEVICE_NAME     "buttons_test"struct button_desc {    int gpio;    int number;    char *name;     struct timer_list timer;};static struct button_desc buttons[] = {    { S5PV210_GPH2(0), 0, "KEY0" },    { S5PV210_GPH2(1), 1, "KEY1" },    { S5PV210_GPH2(2), 2, "KEY2" },    { S5PV210_GPH2(3), 3, "KEY3" },    { S5PV210_GPH3(0), 4, "KEY4" },    { S5PV210_GPH3(1), 5, "KEY5" },    { S5PV210_GPH3(2), 6, "KEY6" },    { S5PV210_GPH3(3), 7, "KEY7" },};static volatile char key_values[] = {    '0', '0', '0', '0', '0', '0', '0', '0'};static DECLARE_WAIT_QUEUE_HEAD(button_waitq);static volatile int ev_press = 0;static struct fasync_struct *button_async;static void mini210_buttons_timer(unsigned long _data){    struct button_desc *bdata = (struct button_desc *)_data;    int down;    int number;    unsigned tmp;    tmp = gpio_get_value(bdata->gpio);    /* active low */    down = !tmp;    printk("KEY %d: %08x\n", bdata->number, down);    number = bdata->number;    if (down != (key_values[number] & 1)) {        key_values[number] = '0' + down;        ev_press = 1;        wake_up_interruptible(&button_waitq);    }}static irqreturn_t button_interrupt(int irq, void *dev_id){    struct button_desc *bdata = (struct button_desc *)dev_id;    mod_timer(&bdata->timer, jiffies + msecs_to_jiffies(40));        //发送信号SIGIO信号给fasync_struct 结构体所描述的PID，触发应用程序的SIGIO信号处理函数      kill_fasync(&button_async, SIGIO, POLL_IN);      return IRQ_HANDLED;}static int mini210_buttons_open(struct inode *inode, struct file *file){    int irq;    int i;    int err = 0;    for (i = 0; i < ARRAY_SIZE(buttons); i++) {        if (!buttons[i].gpio)            continue;        setup_timer(&buttons[i].timer, mini210_buttons_timer,                (unsigned long)&buttons[i]);        irq = gpio_to_irq(buttons[i].gpio);        err = request_irq(irq, button_interrupt, IRQ_TYPE_EDGE_BOTH,                 buttons[i].name, (void *)&buttons[i]);        if (err)            break;    }    if (err) {        i--;        for (; i >= 0; i--) {            if (!buttons[i].gpio)                continue;            irq = gpio_to_irq(buttons[i].gpio);            disable_irq(irq);            free_irq(irq, (void *)&buttons[i]);            del_timer_sync(&buttons[i].timer);        }        return -EBUSY;    }    ev_press = 1;    return 0;}static int mini210_buttons_close(struct inode *inode, struct file *file){    int irq, i;    for (i = 0; i < ARRAY_SIZE(buttons); i++) {        if (!buttons[i].gpio)            continue;        irq = gpio_to_irq(buttons[i].gpio);        free_irq(irq, (void *)&buttons[i]);        del_timer_sync(&buttons[i].timer);    }    return 0;}static int mini210_buttons_read(struct file *filp, char __user *buff,        size_t count, loff_t *offp){    unsigned long err;    if (!ev_press) {        if (filp->f_flags & O_NONBLOCK)            return -EAGAIN;        else            wait_event_interruptible(button_waitq, ev_press);    }    ev_press = 0;    err = copy_to_user((void *)buff, (const void *)(&key_values),            min(sizeof(key_values), count));    return err ? -EFAULT : min(sizeof(key_values), count);}static unsigned int mini210_buttons_poll( struct file *file,        struct poll_table_struct *wait){    unsigned int mask = 0;    poll_wait(file, &button_waitq, wait);    if (ev_press)        mask |= POLLIN | POLLRDNORM;    return mask;}static int mini210_buttons_fasync (int fd, struct file *filp, int on)  {      printk("driver: fifth_drv_fasync\n");      //初始化/释放 fasync_struct 结构体 (fasync_struct->fa_file->f_owner->pid)      return fasync_helper(fd, filp, on, &button_async);} static struct file_operations dev_fops = {    .owner      = THIS_MODULE,    .open       = mini210_buttons_open,    .release    = mini210_buttons_close,     .read       = mini210_buttons_read,    .poll       = mini210_buttons_poll,    .fasync     = mini210_buttons_fasync,};static struct miscdevice misc = {    .minor      = MISC_DYNAMIC_MINOR,    .name       = DEVICE_NAME,    .fops       = &dev_fops,};static int __init button_dev_init(void){    int ret;    ret = misc_register(&misc);    printk(DEVICE_NAME"\tinitialized\n");    return ret;}static void __exit button_dev_exit(void){    misc_deregister(&misc);}module_init(button_dev_init);module_exit(button_dev_exit);MODULE_LICENSE("GPL");MODULE_AUTHOR("FriendlyARM Inc.");

Makefile:

obj-m := my_button.o                   #要生成的模块名     my_buttonmodule-objs:= module        #生成这个模块名所需要的目标文件#KDIR := /lib/modules/`uname -r`/buildKDIR := /opt/FriendlyARM/tiny210/android/linux-3.0.8PWD := $(shell pwd)MAKE:=make  default:    $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules  clean:    $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) clean#default:#   make -C $(KDIR) M=$(PWD) modules#clean:#   rm -rf *.o *.cmd *.ko *.mod.c .tmp_versions

测试代码：buttons_test.c

#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>#include <signal.h>int buttons_fd;int break_flg;char buttons[8] = {'0', '0', '0', '0', '0', '0', '0', '0'};//信号处理函数  void my_signal_fun(int signum)  {      char current_buttons[8];    int count_of_changed_key;    int i;    if (read(buttons_fd, current_buttons, sizeof current_buttons) != sizeof current_buttons) {        perror("read buttons:");        exit(1);    }    for (i = 0, count_of_changed_key = 0; i < sizeof buttons / sizeof buttons[0]; i++) {        if (buttons[i] != current_buttons[i]) {            buttons[i] = current_buttons[i];            printf("%skey %d is %s", count_of_changed_key? ", ": "", i+1, buttons[i] == '0' ? "0" : "1");            count_of_changed_key++;        }    }    if (count_of_changed_key) {        printf("\n");    }    if((buttons[0] == '1')&&(buttons[7]=='1'))    {        printf("key test off\n");break_flg = 1;        //close(buttons_fd);            }}  int main(void){    int Oflags;      break_flg = 0;    //在应用程序中捕捉SIGIO信号（由驱动程序发送）      signal(SIGIO, my_signal_fun);      buttons_fd = open("/dev/buttons_test", 0);    if (buttons_fd < 0) {        perror("open device buttons");        exit(1);    }     //将当前进程PID设置为fd文件所对应驱动程序将要发送SIGIO,SIGUSR信号进程PID       fcntl(buttons_fd, F_SETOWN, getpid());      //获取fd的打开方式      Oflags = fcntl(buttons_fd, F_GETFL);   //将fd的打开方式设置为FASYNC --- 即 支持异步通知  //该行代码执行会触发 驱动程序中 file_operations->fasync 函数 ------fasync函数调用fasync_helper初始化一个fasync_struct结构体，该结构体描述了将要发送信号的进程PID (fasync_struct->fa_file->f_owner->pid)      fcntl(buttons_fd, F_SETFL, Oflags | FASYNC);          while (1)          {          sleep(1000);          if(break_flg == 1)        break;        }     for (;;) {        char current_buttons[8];        int count_of_changed_key;        int i;        if (read(buttons_fd, current_buttons, sizeof current_buttons) != sizeof current_buttons) {            perror("read buttons:");            exit(1);        }        for (i = 0, count_of_changed_key = 0; i < sizeof buttons / sizeof buttons[0]; i++) {            if (buttons[i] != current_buttons[i]) {                buttons[i] = current_buttons[i];                printf("%skey %d is %s", count_of_changed_key? ", ": "", i+1, buttons[i] == '0' ? "0" : "1");                count_of_changed_key++;            }        }        if (count_of_changed_key) {            printf("\n");        }        if((buttons[0] == '1')&&(buttons[7]=='1'))        {            printf("key test off\n");            break;        }    }    close(buttons_fd);    return 0;}