在學習安卓時候對驅動還是有疑惑 ,用jz2440重寫驅動
闆子:jz2440
系統:ubutu16
最後所有代碼在底部
先配置闆子uboot能與主機互相聯通
如果配置是
開發版 192.168.31.10
電腦 192.168.31.5
2440_ubuntu 192.168.31.51
4412 192.168.31.200
配置uboot的ip和伺服器ip
set ipaddr 192.168.31.10
set serverip 192.168.31.51
setenv netmask 255.255.255.0
setenv gatewayip 192.168.31.1
save
![](https://img.laitimes.com/img/9ZDMuAjOiMmIsIjOiQnIsICM38FdsYkRGZkRG9lcvx2bjxiNx8VZ6l2cs0TP35kMBR0T1cmeNBDOsJGcohVYsR2MMBjVtJWd0ckW65UbM5WOHJWa5kHT20ESjBjUIF2X0hXZ0xCMx81dvRWYoNHLrdEZwZ1Rh5WNXp1bwNjW1ZUba9VZwlHdssmch1mclRXY39CXldWYtlWPzNXZj9mcw1ycz9WL49zZuBnL2czMzADOxkTMwEzMwAjMwIzLc52YucWbp5GZzNmLn9Gbi1yZtl2Lc9CX6MHc0RHaiojIsJye.png)
ping 的到虛拟機
可以使用nfs挂載根目錄 闆子啟動根檔案系統在主機上友善傳輸,也可以不弄,在windos傳輸
進入uboot 輸入print
bootarg root(根檔案系統)在nandflash上 改為在虛拟機上
bootcmd 啟動核心的指令
進入闆子的linux 用nfs傳輸檔案
mount -t nfs -o intr,nolock,rsize=1024,wsize=1024 192.168.31.51:/work/nfs_root /mnt
根據button_test.c 編譯出可執行驅動的檔案 button_test
執行make指令生成驅動檔案
裝載驅動檔案
insmod buttons.ko
用 lsmod 檢視裝載了沒有
cat /proc/devices
配置設定給我的裝置号是252
在main函數中 要打開dev/buttons
檢視是否有這個裝置節點
現在已經有了如果沒有手工建立裝置節點
mknod /dev/buttons c 252 0
代碼裡有自動建立裝置節點
register_chrdev 配置設定主裝置号,給核心知道,把驅動注冊進核心數組
class_create 建立一個/sys/class/sixth_dev的類,類下面生成buttons裝置
class_device_create 建立/dev/buttons 檔案,給 app 的 fb = open() 使用
裡面有主裝置号資訊次裝置号資訊
mdev根據這些裝置資訊生成裝置節點
系統自帶的熱拔插程式 當有了裝置資訊後 自動生成裝置節點 應用程式隻要名字對了,打開裡面的裝置節點就能使用
驅動和應用程式交換資料
在驅動程式裡裡有 copy_to_usr copy_from_usr 對應着應用程式裡的read write
copy_to_usr( to, &from, sizeof(from))
To:使用者空間函數 (可以是數組)
From:核心空間函數(可以是數組)
sizeof(from):核心空間要傳遞的數組的長度
驅動代碼
應用代碼
copy_from_usr(&from , to , sizeof(to) )
To:使用者空間函數 (可以是數組)
From:核心空間函數(可以是數組)
sizeof(from):核心空間要傳遞的數組的長度
驅動代碼
應用代碼
button_test.c
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <poll.h>
#include <signal.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
/* sixthdrvtest
*/
int fd;
void my_signal_fun(int signum)
{
unsigned char key_val;
read(fd, &key_val, 1);
printf("key_val: 0x%x\n", key_val);
}
int main(int argc, char **argv)
{
unsigned char key_val;
int ret;
int Oflags;
//signal(SIGIO, my_signal_fun);
fd = open("/dev/buttons", O_RDWR);
if (fd < 0)
{
printf("can't open!\n");
return -1;
}
//fcntl(fd, F_SETOWN, getpid());
//Oflags = fcntl(fd, F_GETFL);
//fcntl(fd, F_SETFL, Oflags | FASYNC);
while (1)
{
ret = read(fd, &key_val, 1);
printf("key_val: 0x%x, ret = %d\n", key_val, ret);
//sleep(5);
}
return 0;
}
button.c(驅動檔案,用makefile編譯)
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <asm/uaccess.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/arch/regs-gpio.h>
#include <asm/hardware.h>
#include <linux/poll.h>
static struct class *sixthdrv_class;
static struct class_device *sixthdrv_class_dev;
volatile unsigned long *gpfcon;
volatile unsigned long *gpfdat;
volatile unsigned long *gpgcon;
volatile unsigned long *gpgdat;
static struct timer_list buttons_timer;
static DECLARE_WAIT_QUEUE_HEAD(button_waitq);
/* 中斷事件标志, 中斷服務程式将它置1,sixth_drv_read将它清0 */
static volatile int ev_press = 0;
static struct fasync_struct *button_async;
struct pin_desc{
unsigned int pin;
unsigned int key_val;
};
/* 鍵值: 按下時, 0x01, 0x02, 0x03, 0x04 */
/* 鍵值: 松開時, 0x81, 0x82, 0x83, 0x84 */
static unsigned char key_val;
struct pin_desc pins_desc[4] = {
{S3C2410_GPF0, 0x01},
{S3C2410_GPF2, 0x02},
{S3C2410_GPG3, 0x03},
{S3C2410_GPG11, 0x04},
};
static struct pin_desc *irq_pd;
//static atomic_t canopen = ATOMIC_INIT(1); //定義原子變量并初始化為1
static DECLARE_MUTEX(button_lock); //定義互斥鎖
/*
* 确定按鍵值
*/
static irqreturn_t buttons_irq(int irq, void *dev_id)
{
/* 10ms後啟動定時器 */
irq_pd = (struct pin_desc *)dev_id;
mod_timer(&buttons_timer, jiffies+HZ/100);
return IRQ_RETVAL(IRQ_HANDLED);
}
static int sixth_drv_open(struct inode *inode, struct file *file)
{
#if 0
if (!atomic_dec_and_test(&canopen))
{
atomic_inc(&canopen);
return -EBUSY;
}
#endif
if (file->f_flags & O_NONBLOCK)
{
if (down_trylock(&button_lock))
return -EBUSY;
}
else
{
/* 擷取信号量 */
down(&button_lock);
}
/* 配置GPF0,2為輸入引腳 */
/* 配置GPG3,11為輸入引腳 */
request_irq(IRQ_EINT0, buttons_irq, IRQT_BOTHEDGE, "S2", &pins_desc[0]);
request_irq(IRQ_EINT2, buttons_irq, IRQT_BOTHEDGE, "S3", &pins_desc[1]);
request_irq(IRQ_EINT11, buttons_irq, IRQT_BOTHEDGE, "S4", &pins_desc[2]);
request_irq(IRQ_EINT19, buttons_irq, IRQT_BOTHEDGE, "S5", &pins_desc[3]);
return 0;
}
ssize_t sixth_drv_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{
if (size != 1)
return -EINVAL;
if (file->f_flags & O_NONBLOCK)
{
if (!ev_press)
return -EAGAIN;
}
else
{
/* 如果沒有按鍵動作, 休眠 */
wait_event_interruptible(button_waitq, ev_press);
}
/* 如果有按鍵動作, 傳回鍵值 */
copy_to_user(buf, &key_val, 1);
ev_press = 0;
return 1;
}
int sixth_drv_close(struct inode *inode, struct file *file)
{
//atomic_inc(&canopen);
free_irq(IRQ_EINT0, &pins_desc[0]);
free_irq(IRQ_EINT2, &pins_desc[1]);
free_irq(IRQ_EINT11, &pins_desc[2]);
free_irq(IRQ_EINT19, &pins_desc[3]);
up(&button_lock);
return 0;
}
static unsigned sixth_drv_poll(struct file *file, poll_table *wait)
{
unsigned int mask = 0;
poll_wait(file, &button_waitq, wait); // 不會立即休眠
if (ev_press)
mask |= POLLIN | POLLRDNORM;
return mask;
}
static int sixth_drv_fasync (int fd, struct file *filp, int on)
{
printk("driver: sixth_drv_fasync\n");
return fasync_helper (fd, filp, on, &button_async);
}
static struct file_operations sencod_drv_fops = {
.owner = THIS_MODULE, /* 這是一個宏,推向編譯子產品時自動建立的__this_module變量 */
.open = sixth_drv_open,
.read = sixth_drv_read,
.release = sixth_drv_close,
.poll = sixth_drv_poll,
.fasync = sixth_drv_fasync,
};
int major;
static void buttons_timer_function(unsigned long data)
{
struct pin_desc * pindesc = irq_pd;
unsigned int pinval;
if (!pindesc)
return;
pinval = s3c2410_gpio_getpin(pindesc->pin);
if (pinval)
{
/* 松開 */
key_val = 0x80 | pindesc->key_val;
}
else
{
/* 按下 */
key_val = pindesc->key_val;
}
ev_press = 1; /* 表示中斷發生了 */
wake_up_interruptible(&button_waitq); /* 喚醒休眠的程序 */
kill_fasync (&button_async, SIGIO, POLL_IN);
}
static int sixth_drv_init(void)
{
init_timer(&buttons_timer);
buttons_timer.function = buttons_timer_function;
//buttons_timer.expires = 0;
add_timer(&buttons_timer);
major = register_chrdev(0, "sixth_drv", &sencod_drv_fops);//給核心知道
sixthdrv_class = class_create(THIS_MODULE, "sixth_drv");
/* 為了讓mdev根據這些資訊來建立裝置節點 */
sixthdrv_class_dev = class_device_create(sixthdrv_class, NULL, MKDEV(major, 0), NULL, "buttons"); /* /dev/buttons */
gpfcon = (volatile unsigned long *)ioremap(0x56000050, 16);
gpfdat = gpfcon + 1;
gpgcon = (volatile unsigned long *)ioremap(0x56000060, 16);
gpgdat = gpgcon + 1;
return 0;
}
static void sixth_drv_exit(void)
{
unregister_chrdev(major, "sixth_drv");
class_device_unregister(sixthdrv_class_dev);
class_destroy(sixthdrv_class);
iounmap(gpfcon);
iounmap(gpgcon);
return 0;
}
module_init(sixth_drv_init);
module_exit(sixth_drv_exit);
MODULE_LICENSE("GPL");
makefile
KERN_DIR = /work/system/linux-2.6.22.6
all:
make -C $(KERN_DIR) M=`pwd` modules
clean:
make -C $(KERN_DIR) M=`pwd` modules clean
rm -rf modules.order
obj-m += buttons.o
KERM_DIR是驅動程式要根據所用核心才能編譯出 虛拟機裡要有這個核心