linux中断和异步通知 基于QT210

linux异步通知：

应用程序需要完成如下三个步骤：

1）signal(SIGIO, sig_handler);

调用signal函数，让指定的信号SIGIO与处理函数sig_handler对应。

2）fcntl(fd, F_SET_OWNER, getpid());

指定一个进程作为文件的“属主(filp->owner)”，这样内核才知道信号要发给哪个进程。

3）f_flags = fcntl(fd, F_GETFL);

fcntl(fd, F_SETFL, f_flags | FASYNC);

在设备文件中添加FASYNC标志，驱动中就会调用将要实现的test_fasync函数。

三个步骤执行后，一旦有信号产生，相应的进程就会收到。

内核需要完成下面四个步骤：

1）定义结构体fasync_struct。

struct fasync_struct *async_queue;

2）实现test_fasync，把函数fasync_helper将fd,filp和定义的结构体传给内核。

 int test_fasync (int fd, struct file *filp, int mode)

 {

 struct _test_t *dev = filp->private_data;

 return fasync_helper(fd, filp, mode, &dev->async_queue);

 } 

3）当设备可写时，调用函数kill_fasync发送信号SIGIO给内核。

 if (dev->async_queue){

 kill_fasync(&dev->async_queue, SIGIO, POLL_IN);

 }

4）完成ops

 struct file_operations test_fops = {

 .open = test_open,

 .release = test_close,

 .write = test_write,

 .read = test_read,

 .poll = test_poll,

 .fasync = test_fasync

基于QT210和linux3.4.2设置如下：

配置内核：

参考原理图：

编译内核代码：

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include  
#include 
#include 
#include 
#include 
#include 
#include 
static dev_t devno;
static struct cdev cdev;
static struct class* buttons_class;
static struct device* buttons_device;

static wait_queue_head_t button_waitq;
static struct timer_list buttons_timer;

static volatile int pressed = 0;
static unsigned int key_val;

static struct fasync_struct *button_async;

struct key_desc{
	unsigned int  pin;
	unsigned char value;
};
static struct key_desc *irq_pd;

static volatile unsigned long *gph3con;
static volatile unsigned long *gph3dat;
static struct key_desc key_descs[8] = {
	[0] = {
		.pin = S5PV210_GPH2(3),
		.value = 0x00,
	},

	[1] = {
		.pin = S5PV210_GPH2(4),
		.value = 0x01,
	},

	[2] = {
		.pin = S5PV210_GPH2(5),
		.value = 0x02,
	},

	[3] = {
		.pin = S5PV210_GPH2(6),
		.value = 0x03,
	},

	[4] = {
		.pin = S5PV210_GPH2(7),
		.value = 0x04,
	},
};
static void buttons_timer_function(unsigned long data)
{
	struct key_desc * pindesc = irq_pd;
	unsigned int pinval;
	if (!pindesc)
		return;
	pinval = gpio_get_value(pindesc->pin);

	if (pinval)
	{
		/* 松开 */
		key_val = 0x80 | pindesc->value;
	}
	else
	{
		/* 按下 */
		key_val = pindesc->value;
	}
	pressed = 1;
	wake_up_interruptible(&button_waitq);
	
	kill_fasync (&button_async, SIGIO, POLL_IN);
}

static irqreturn_t buttons_irq(int irq, void *dev_id){
	printk("buttons_irq happen\n");
	/* 10ms后启动定时器 */
	irq_pd = (struct key_desc *)dev_id;
	mod_timer(&buttons_timer, jiffies+HZ/100);
	return IRQ_RETVAL(IRQ_HANDLED);
}

static int buttons_open(struct inode *inode, struct file *file){
	int ret;

	
	ret = request_irq(IRQ_EINT(19),   buttons_irq, IRQ_TYPE_EDGE_BOTH, "key1", &key_descs[0]);
	if(ret)
		return ret;
	ret = request_irq(IRQ_EINT(20),   buttons_irq, IRQ_TYPE_EDGE_BOTH, "key2", &key_descs[1]);
	if(ret)
		return ret;
 	ret = request_irq(IRQ_EINT(21),   buttons_irq, IRQ_TYPE_EDGE_BOTH, "key3", &key_descs[2]);
	if(ret)
		return ret;
 	ret = request_irq(IRQ_EINT(22),   buttons_irq, IRQ_TYPE_EDGE_BOTH, "key4", &key_descs[3]);
	if(ret)
		return ret;
	ret = request_irq(IRQ_EINT(23),   buttons_irq, IRQ_TYPE_EDGE_BOTH, "key5", &key_descs[4]);
	if(ret)
		return ret;
	return 0;
}

static ssize_t buttons_read(struct file * file, char __user *data, size_t count, loff_t *loff){
	
	if (count != 1)
		return -EINVAL;

	if (file->f_flags & O_NONBLOCK)
	{
		if (!pressed)
			return -EAGAIN;
	}

	wait_event_interruptible(button_waitq, pressed);
	pressed = 0;

	if(copy_to_user(data, &key_val, 1)){
		printk(KERN_ERR "The driver can not copy the data to user area!\n");
		return -ENOMEM;
	}
	
	return 0;
}

static int buttons_close(struct inode *inode, struct file *file){
	free_irq(IRQ_EINT(19),  &key_descs[0]);
	free_irq(IRQ_EINT(20),  &key_descs[1]);	
	free_irq(IRQ_EINT(21),  &key_descs[2]);
	free_irq(IRQ_EINT(22),  &key_descs[3]);
	free_irq(IRQ_EINT(23),  &key_descs[4]);
	return 0;
}
static int buttons_fasync (int fd, struct file *filp, int on)
{
	printk("driver: buttons_fasync\n");
	return fasync_helper (fd, filp, on, &button_async);
}
struct file_operations buttons_ops = {
	.open    = buttons_open,
	.read    = buttons_read,
	.release = buttons_close,
	.fasync	 = buttons_fasync,
};

int buttons_init(void){
	int ret;

	init_timer(&buttons_timer);
	buttons_timer.function = buttons_timer_function;
	//buttons_timer.expires  = 0;
	add_timer(&buttons_timer); 
	
	cdev_init(&cdev, &buttons_ops);
	cdev.owner = THIS_MODULE;

	ret = alloc_chrdev_region(&devno, 0, 1, "buttons");
	if(ret){
		printk(KERN_ERR "alloc char device region faild!\n");
		return ret;
	}

	ret = cdev_add(&cdev, devno, 1);
	if(ret){
		printk(KERN_ERR "add char device faild!\n");
		goto add_error;
	}

	buttons_class = class_create(THIS_MODULE, "buttonsdrv");
	if(IS_ERR(buttons_class)){
		printk(KERN_ERR "create class error!\n");
		goto class_error;
	}

	buttons_device = device_create(buttons_class, NULL, devno, NULL, "buttons");
	if(IS_ERR(buttons_device)){
		printk(KERN_ERR "create buttons device error!\n");
		goto device_error;
	}

	init_waitqueue_head(&button_waitq);
	gph3con = (volatile unsigned long *)ioremap(0xE0200C60, 16);
	gph3dat = gph3con + 1;

	*gph3con &= (~0x000000ff);
	*gph3con |=0x11;
	*gph3dat &= ~0x03;	

	
	printk("buttons init\n");
	return 0;

device_error:
	class_destroy(buttons_class);
class_error:
	cdev_del(&cdev);
add_error:
	unregister_chrdev_region(devno,1);

	return -ENODEV;
}

void buttons_exit(void){
	printk("buttons exit\n");
	device_destroy(buttons_class, devno);
	class_destroy(buttons_class);
	cdev_del(&cdev);
	unregister_chrdev_region(devno, 1);
}

module_init(buttons_init);
module_exit(buttons_exit);
MODULE_LICENSE("GPL");

编译用户测试代码：

#include 
#include 
#include 
#include 
#include 
#include 
#include 


int fd; 

void sig_handler(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, sig_handler);

    fd = open("/dev/buttons", O_RDWR | O_NONBLOCK);
    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);

    return 0;
}

测试结果如下：

[210_Liujia]#insmod buttons.ko
[210_Liujia]#./buttons_test
key_val: 0x1
key_val: 0x81
key_val: 0x0
key_val: 0x80
key_val: 0x2
key_val: 0x82
key_val: 0x3
key_val: 0x83
key_val: 0x4
key_val: 0x84
key_val: 0x1
key_val: 0x81
key_val: 0x2
key_val: 0x82
key_val: 0x4
key_val: 0x84
key_val: 0x3
key_val: 0x83