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 <linux/types.h>#include <linux/module.h>#include <linux/cdev.h>#include <linux/fs.h>#include <linux/device.h>#include <linux/gpio.h>#include <linux/irq.h>#include <linux/interrupt.h>#include <linux/sched.h> #include <linux/wait.h>#include <linux/uaccess.h>#include <mach/gpio.h>#include <asm/uaccess.h>#include <asm/irq.h>#include <asm/io.h>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 <fcntl.h>#include <stdio.h>#include <poll.h>#include <signal.h>#include <sys/types.h>#include <unistd.h>#include <fcntl.h>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_testkey_val: 0x1key_val: 0x81key_val: 0x0key_val: 0x80key_val: 0x2key_val: 0x82key_val: 0x3key_val: 0x83key_val: 0x4key_val: 0x84key_val: 0x1key_val: 0x81key_val: 0x2key_val: 0x82key_val: 0x4key_val: 0x84key_val: 0x3key_val: 0x83