arm 驅(qū)動(dòng)linux內(nèi)核驅(qū)動(dòng)之中斷下半部編程

中斷上半部要求執(zhí)行時(shí)間間隔段，所以往往將處理時(shí)間較長的代碼放在中斷下半部來處理

中斷下半部的應(yīng)用：網(wǎng)卡驅(qū)動(dòng)上半部初始化網(wǎng)卡驅(qū)動(dòng)等短時(shí)間的事件，下半部收發(fā)數(shù)據(jù)

中斷下半部：

a， 下半部產(chǎn)生的原因：

1，中斷上下文中不能阻塞，這也限制了中斷上下文中能干的事

2，中斷處理函數(shù)執(zhí)行過程中仍有可能被其他中斷打斷，都希望中斷處理函數(shù)執(zhí)行得越快越好。

基于上面的原因，內(nèi)核將整個(gè)的中斷處理流程分為了上半部和下半部。上半部就是之前所說的中斷處理函數(shù)，它能最快的響應(yīng)中斷，并且做一些必須在中斷響應(yīng)之后馬上要做的事情。而一些需要在中斷處理函數(shù)后繼續(xù)執(zhí)行的操作，內(nèi)核建議把它放在下半部執(zhí)行。

比如：在linux內(nèi)核中，當(dāng)網(wǎng)卡一旦接受到數(shù)據(jù)，網(wǎng)卡會(huì)通過中斷告訴內(nèi)核處理數(shù)據(jù)，內(nèi)核會(huì)在網(wǎng)卡中斷處理函數(shù)（上半部）執(zhí)行一些網(wǎng)卡硬件的必要設(shè)置，因?yàn)檫@是在中斷響應(yīng)后急切要干的事情。接著，內(nèi)核調(diào)用對(duì)應(yīng)的下半部函數(shù)來處理網(wǎng)卡接收到的數(shù)據(jù)，因?yàn)閿?shù)據(jù)處理沒必要在中斷處理函數(shù)里面馬上執(zhí)行，可以將中斷讓出來做更緊迫的事情

b，中斷下半部實(shí)現(xiàn)的機(jī)制分類

tasklet：

workqueue：工作隊(duì)列

timer：定時(shí)器

其實(shí)還有一種，叫softirq，但要寫代碼的話，就必須修改原來的內(nèi)核框架代碼，在實(shí)際開發(fā)中用的比較少，tasklet內(nèi)部實(shí)現(xiàn)就是用softeirq

c， 中斷下半部實(shí)現(xiàn)方法

1， tasklet的編程方式

1.1 : 定義并初始化結(jié)構(gòu)體tasklet_struct(一般在哪里初始化：是在模塊卸載方法中)

struct tasklet_struct

{

struct tasklet_struct *next; // l鏈表

unsigned long state;

atomic_t count;

void (*func)(unsigned long); // 下半部處理方法的實(shí)現(xiàn)

unsigned long data;//給處理函數(shù)的傳參

};

初始化方式：

靜態(tài)：DECLARE_TASKLET(name, func, data)；

DCLARE_TASKLET_DISABLED初始化后的處于禁止?fàn)顟B(tài)，暫時(shí)不能被使用（不是中斷），除非被激活

參數(shù)1:tasklet_struct 的變量名字，自定義

參數(shù)2：中斷下半部執(zhí)行的處理函數(shù).類型為函數(shù)指針

參數(shù)3：處理函數(shù)帶的參數(shù)

動(dòng)態(tài)：void tasklet_init(struct tasklet_struct * t, void(* func)(unsigned long), unsigned long data);

參數(shù)1:tasklet_struct 對(duì)象

參數(shù)2：中斷下半部執(zhí)行的處理函數(shù)

參數(shù)3：處理函數(shù)帶的參數(shù)

1.2: 在中斷上半部中調(diào)度下半部

void tasklet_schedule(struct tasklet_struct * t);

1.3: 在模塊卸載時(shí)，銷毀這個(gè)tasklet_struct 對(duì)象

void tasklet_kill(struct tasklet_struct *t)

1.4:原理：初始化好struct tasklet_struct對(duì)象后，tasklet_schedule()會(huì)將tasklet對(duì)象加到鏈表中，內(nèi)核稍后會(huì)去調(diào)度這個(gè)tasklet對(duì)象

1.5： 特點(diǎn)：優(yōu)先級(jí)高，調(diào)度快，運(yùn)行在中斷上下文中，所以在處理方法中，不能執(zhí)行阻塞/睡眠的操作

2，workqueque編程方式：

2.1 ：定義并初始化workqueue_struct(一個(gè)隊(duì)列)和work_struct(隊(duì)列中的一項(xiàng)工作)對(duì)象

work_struct對(duì)象的初始化

struct work_struct {

atomic_long_t data; // 傳遞給work的參數(shù)

struct list_head entry; // 所在隊(duì)列的鏈表

work_func_t func; // work對(duì)應(yīng)的處理方法

};

靜態(tài)：DECLARE_WORK(n, f)

參數(shù)1: 變量名，自定義

參數(shù)2：work對(duì)應(yīng)的處理方法，類型為函數(shù)指針

動(dòng)態(tài)：INIT_WORK(_work, _func)

參數(shù)1: 指針，先聲明一個(gè)struct work_struct變量，將變量地址填入

參數(shù)2：work對(duì)應(yīng)的處理方法，類型為函數(shù)指針

返回值： 返回值為void

workqueue_struct對(duì)象的初始化：(其實(shí)就是一個(gè)內(nèi)核線程)

1， 重新創(chuàng)建一個(gè)隊(duì)列

create_workqueue(name)//這個(gè)本身就是一個(gè)宏

參數(shù)：名字，自定義,用于識(shí)別

返回值：struct workqueue_struct *

2， 系統(tǒng)在開機(jī)的時(shí)候自動(dòng)創(chuàng)建一個(gè)隊(duì)列

2.2 將工作對(duì)象加入工作隊(duì)列中，并參與調(diào)度(注意不是馬上調(diào)度，該步驟也是中斷上半部中調(diào)用)

int queue_work(struct workqueue_struct *wq, struct work_struct *work)

參數(shù)1：工作隊(duì)列

參數(shù)2: 工作對(duì)象

返回值： 0表示已經(jīng)放到隊(duì)列上了(也即時(shí)說本次屬于重復(fù)操作)，其實(shí)一般我們都不會(huì)去做出錯(cuò)處理

2.3 在模塊注銷的時(shí)候，銷毀工作隊(duì)列和工作對(duì)象

void flush_workqueue(struct workqueue_struct * wq)

該函數(shù)會(huì)一直等待，知道指定的等待隊(duì)列中所有的任務(wù)都執(zhí)行完畢并從等待隊(duì)列中移除。

void destroy_workqueue(struct workqueue_struct * wq);

該函數(shù)是是創(chuàng)建等待隊(duì)列的反操作，注銷掉指定的等待隊(duì)列。

2.4： 對(duì)于使用內(nèi)核自帶的工作隊(duì)列events， 操作步驟如下：

2.4.1 初始化工作對(duì)象，無需創(chuàng)建隊(duì)列了

靜態(tài)：DECLARE_WORK(n, f)

動(dòng)態(tài)：INIT_WORK(_work, _func)

2.4.2將工作加入隊(duì)列并調(diào)度（在中斷上半部中調(diào)度）

int schedule_work(struct work_struct * work)

只要兩步驟就完成，也不需要刷新，也不要銷毀，因?yàn)檫@個(gè)工作隊(duì)列是系統(tǒng)管理的，我們不用管

2.5：原理梳理：在工作隊(duì)列中，有專門的工作者線程來處理加入到工作對(duì)列中的任務(wù)。工作對(duì)列對(duì)應(yīng)的工作者線程可能不止一個(gè)，每個(gè)處理器有且僅有一個(gè)工作隊(duì)列 對(duì)應(yīng)的工作者線程，在內(nèi)核中有一個(gè)默認(rèn)的工作隊(duì)列events，對(duì)于單處理器只有一個(gè)對(duì)應(yīng)的工作者線程

3， 定時(shí)器timer編程方式：（以上兩個(gè)下半部處理都是內(nèi)核在一個(gè)特定的時(shí)候進(jìn)行調(diào)度，時(shí)間不定，而timer可以指定某個(gè)時(shí)間點(diǎn)執(zhí)行）

3.1, jiffies,表示從系統(tǒng)啟動(dòng)到當(dāng)前的時(shí)間值，一般做加法（+5HZ(5s),）

3.2， 定義并初始化 timer_list對(duì)象

struct timer_list {

struct list_head entry; // 鏈表

unsigned long expires; // 過期時(shí)間。也及時(shí)在什么時(shí)候執(zhí)行處理方法

struct tvec_base *base;

void (*function)(unsigned long); // 處理方法

unsigned long data; // 處理方法可以傳遞的參數(shù)

int slack;

};

靜態(tài)初始化：TIMER_INITIALIZER(_function, _expires, _data)

動(dòng)態(tài)初始化：void init_timer(timer)

參數(shù)：為一個(gè)指針，需要傳遞一個(gè)struct timer_list對(duì)象的地址

該函數(shù)只是初始化了timer_list對(duì)象的部分成員，還有以下成員是需要編程的：

struct timer_list mytimer;

init_timer(&mytimer);

mytimer.expires = jiffies + 2HZ

mytimer.fuction = my_timer_func; // 自己去實(shí)現(xiàn)

mytimer.data = (unsigned long)99; // 可以傳遞參數(shù)

3.3， 激活timer，開始計(jì)時(shí) (一般也是放在中斷上半部完成)

void add_timer(&mytimer);

3.4 計(jì)時(shí)結(jié)束是，也就是要執(zhí)行處理函數(shù)時(shí)，執(zhí)行函數(shù)中要下一次計(jì)時(shí)的話，必須修改timer

mod_timer(&my_timer, jiffies + 2*HZ);

// 2s之后再來，相當(dāng)于如下：

my_timer.expires = jiffies + 2*HZ; //重新設(shè)定時(shí)間，在兩秒后再執(zhí)行

add_timer(&my_timer); //再次激活定時(shí)器

3.5 定時(shí)器的銷毀

int del_timer(struct timer_list *timer) // 該函數(shù)用來刪除還沒超時(shí)的定時(shí)器

timer定時(shí)器的中斷上下半部代碼

#include
#include
#include
#include
#include
#include
#include
#include interrupt.h>
#include

#include arm/param.h>
#include
#include
#define VIRTUAL_MAJOR 250
int major = VIRTUAL_MAJOR;

struct myirq_desc{
int irq_id;
char *irq_name;
int irq_code;
};

struct myirq_desc myirq_descs[3]= {
{S3C2410_GPF0, "s2", KEY_A},
{S3C2410_GPF2, "s3", KEY_K},
{S3C2410_GPG3, "s4", KEY_Z},
};
struct VirtualDisk{
struct class *mycdevclass;//在/sys/class創(chuàng)建類
struct class_device *mycdevclassdevice;//在/dev下創(chuàng)建設(shè)備
struct cdev mycdev;//給設(shè)備添加相關(guān)的fileoption
struct timer_list mytimer;
};
struct VirtualDisk *myvirtualdisk;

static struct file_operations mydev_fops = {
.owner = THIS_MODULE,
};
static void mytimer_func(unsigned long fundata){
printk("*******%s********n", __FUNCTION__);
struct VirtualDisk *myvirtualdisk_fun = (struct VirtualDisk *)(fundata);
myvirtualdisk_fun->mytimer.expires =jiffies + 2 * HZ;
add_timer(&myvirtualdisk_fun->mytimer);
printk("timer func happened!n");
}
static irqreturn_t myirq_handle(int irq, void *dev_id){
struct myirq_desc *myirq_descone = (struct myirq_desc *)dev_id;
printk("*******%s********n", __FUNCTION__);
printk("irq = %d, irq_id = %d,irq_name = %s, irq_code = %cn", irq, myirq_descone->irq_id, myirq_descone->irq_name, myirq_descone->irq_code);
mod_timer(&myvirtualdisk->mytimer, jiffies + 2*HZ);
return IRQ_RETVAL(IRQ_HANDLED);
}

static int __init cdevtest_init(void){
dev_t mydev = MKDEV(major, 0);
int ret;
int i = 0;
printk("*******%s********n", __FUNCTION__);
if(major){//注冊(cè)proc/devices
ret = register_chrdev_region(mydev, 1, "mynewdriver");
}else{
ret = alloc_chrdev_region(&mydev, 0, 1, "mynewdriver");
major = MAJOR(mydev);
}
if(ret < 0){
printk(KERN_ERR "register_chrdev_region failed!n");
ret = -EINVAL;
return ret;
}
myvirtualdisk = kmalloc(sizeof(struct VirtualDisk), GFP_KERNEL);
if(!myvirtualdisk){
ret = -ENOMEM;
printk(KERN_ERR "kmalloc myvirtualdisk failed!n");
goto release_chrdev;
}
myvirtualdisk->mycdevclass = class_create(THIS_MODULE, "mynewdriver");
if(IS_ERR(myvirtualdisk->mycdevclass)){
ret = PTR_ERR(myvirtualdisk->mycdevclass);
printk(KERN_ERR "class_create failed!n");
goto release_mem_malloc;

}
myvirtualdisk->mycdevclassdevice = class_device_create(myvirtualdisk->mycdevclass, NULL, MKDEV(major, 0), NULL, "mynewdriver");
if(IS_ERR(myvirtualdisk->mycdevclassdevice)){
ret = PTR_ERR(myvirtualdisk->mycdevclassdevice);
printk(KERN_ERR "class_device_create failed!n");
goto release_class_create;
}

cdev_init(&(myvirtualdisk->mycdev), &mydev_fops);
myvirtualdisk->mycdev.owner = THIS_MODULE;
ret = cdev_add(&myvirtualdisk->mycdev, MKDEV(major, 0), 1);

//這里把timer相關(guān)的放在irq前面，不然會(huì)有bug出現(xiàn)(當(dāng)在insmod時(shí)候按下按鈕就會(huì)出錯(cuò))
init_timer(&myvirtualdisk->mytimer);
myvirtualdisk->mytimer.function = mytimer_func;
myvirtualdisk->mytimer.data = (unsigned long)myvirtualdisk;

if(ret < 0){
goto release_device_class_create;
}
for(i = 0; i < 3; i++)
{
ret = request_irq(gpio_to_irq(myirq_descs[i].irq_id), myirq_handle, IRQF_TRIGGER_FALLING, myirq_descs[i].irq_name, &myirq_descs[i]);
if(ret < 0){
printk(KERN_ERR "request irq failed!n");
ret =-EFAULT;
goto release_cdevandtimer;
}
}

return 0;
release_cdevandtimer:
del_timer(&myvirtualdisk->mytimer);
cdev_del(&myvirtualdisk->mycdev);
release_device_class_create:
class_device_unregister(myvirtualdisk->mycdevclassdevice);
release_class_create:
class_destroy(myvirtualdisk->mycdevclass);
release_mem_malloc:
kfree(myvirtualdisk);
release_chrdev:
unregister_chrdev_region(MKDEV(major, 0), 1);
return ret;
}

static void __exit cdevtest_exit(void){
int i = 0;
printk("*******%s****1****n", __FUNCTION__);
del_timer(&myvirtualdisk->mytimer);
printk("*******%s*****2***n", __FUNCTION__);
for(i = 0; i < 3; i++)free_irq(gpio_to_irq(myirq_descs[i].irq_id), &myirq_descs[i]);
printk("*******%s*****3***n", __FUNCTION__);
cdev_del(&myvirtualdisk->mycdev);
printk("*******%s*****4***n", __FUNCTION__);
class_device_unregister(myvirtualdisk->mycdevclassdevice);
printk("*******%s*****5***n", __FUNCTION__);
class_destroy(myvirtualdisk->mycdevclass);
printk("*******%s*****6***n", __FUNCTION__);
kfree(myvirtualdisk);
printk("*******%s********n", __FUNCTION__);
unregister_chrdev_region(MKDEV(major, 0), 1);
printk("*******%s*****7***n", __FUNCTION__);
}

module_init(cdevtest_init);
module_exit(cdevtest_exit);
MODULE_LICENSE("GPL");

完整的tasklet任務(wù)中斷上下半部代碼

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

#include
#include
#include
#define VIRTUAL_MAJOR 250
int major = VIRTUAL_MAJOR;

struct myirq_desc{
int irq_id;
char *irq_name;
int irq_code;
};

struct myirq_desc myirq_descs[3]= {
{S3C2410_GPF0, "s2", KEY_J},
{S3C2410_GPF2, "s3", KEY_K},
{S3C2410_GPG3, "s4", KEY_Z},
};
struct VirtualDisk{
struct class *mycdevclass;//在/sys/class創(chuàng)建類
struct class_device *mycdevclassdevice;//在/dev下創(chuàng)建設(shè)備
struct cdev mycdev;//給設(shè)備添加相關(guān)的fileoption
struct timer_list mytimer;
struct tasklet_struct mytasklet;
};
struct VirtualDisk *myvirtualdisk;

static struct file_operations mydev_fops = {
.owner = THIS_MODULE,
};
static void mytasklet_func(unsigned long fundata){
printk("*****%s******,date = %ldn", __FUNCTION__, fundata);
}
static void mytimer_func(unsigned long fundata){
printk("*******%s********n", __FUNCTION__);
struct VirtualDisk *myvirtualdisk_fun = (struct VirtualDisk *)(fundata);
//myvirtualdisk_fun->mytimer.expires =jiffies + 2 * HZ;
//add_timer(&myvirtualdisk_fun->mytimer);
printk("timer func happened!n");
}
static irqreturn_t myirq_handle(int irq, void *dev_id){
struct myirq_desc *myirq_descone = (struct myirq_desc *)dev_id;
printk("*******%s********n", __FUNCTION__);
printk("irq = %d, irq_id = %d,irq_name = %s, irq_code = %cn", irq, myirq_descone->irq_id, myirq_descone->irq_name, myirq_descone->irq_code);
tasklet_schedule(&myvirtualdisk->mytasklet);//激發(fā)任務(wù)，將mytasklet_func加入系統(tǒng)任務(wù)
mod_timer(&myvirtualdisk->mytimer, jiffies + 2*HZ);
return IRQ_RETVAL(IRQ_HANDLED);
}

static int __init cdevtest_init(void){
dev_t mydev = MKDEV(major, 0);
int ret;
int i = 0;
printk("*******%s********n", __FUNCTION__);
if(major){//注冊(cè)proc/devices
ret = register_chrdev_region(mydev, 1, "mynewdriver");
}else{
ret = alloc_chrdev_region(&mydev, 0, 1, "mynewdriver");
major = MAJOR(mydev);
}
if(ret < 0){
printk(KERN_ERR "register_chrdev_region failed!n");
ret = -EINVAL;
return ret;
}
myvirtualdisk = kmalloc(sizeof(struct VirtualDisk), GFP_KERNEL);
if(!myvirtualdisk){
ret = -ENOMEM;
printk(KERN_ERR "kmalloc myvirtualdisk failed!n");
goto release_chrdev;
}
myvirtualdisk->mycdevclass = class_create(THIS_MODULE, "mynewdriver");
if(IS_ERR(myvirtualdisk->mycdevclass)){
ret = PTR_ERR(myvirtualdisk->mycdevclass);
printk(KERN_ERR "class_create failed!n");
goto release_mem_malloc;

}
myvirtualdisk->mycdevclassdevice = class_device_create(myvirtualdisk->mycdevclass, NULL, MKDEV(major, 0), NULL, "mynewdriver");
if(IS_ERR(myvirtualdisk->mycdevclassdevice)){
ret = PTR_ERR(myvirtualdisk->mycdevclassdevice);
printk(KERN_ERR "class_device_create failed!n");
goto release_class_create;
}

cdev_init(&(myvirtualdisk->mycdev), &mydev_fops);
myvirtualdisk->mycdev.owner = THIS_MODULE;
ret = cdev_add(&myvirtualdisk->mycdev, MKDEV(major, 0), 1);

//tasklet 任務(wù)調(diào)度
tasklet_init(&myvirtualdisk->mytasklet, mytasklet_func, (unsigned long) 90);

//這里把timer相關(guān)的放在irq前面，不然會(huì)有bug出現(xiàn)(當(dāng)在insmod時(shí)候按下按鈕就會(huì)出錯(cuò))
init_timer(&myvirtualdisk->mytimer);
myvirtualdisk->mytimer.function = mytimer_func;
myvirtualdisk->mytimer.data = (unsigned long)myvirtualdisk;

if(ret < 0){
goto release_device_class_create;
}
for(i = 0; i < 3; i++)
{
ret = request_irq(gpio_to_irq(myirq_descs[i].irq_id), myirq_handle, IRQF_TRIGGER_FALLING, myirq_descs[i].irq_name, &myirq_descs[i]);
if(ret < 0){
printk(KERN_ERR "request irq failed!n");
ret =-EFAULT;
goto release_cdevandtimer;
}
}

return 0;
release_cdevandtimer:
tasklet_kill(&myvirtualdisk->mytasklet);//刪除任務(wù)
del_timer(&myvirtualdisk->mytimer);
cdev_del(&myvirtualdisk->mycdev);
release_device_class_create:
class_device_unregister(myvirtualdisk->mycdevclassdevice);
release_class_create:
class_destroy(myvirtualdisk->mycdevclass);
release_mem_malloc:
kfree(myvirtualdisk);
release_chrdev:
unregister_chrdev_region(MKDEV(major, 0), 1);
return ret;
}

static void __exit cdevtest_exit(void){
int i = 0;
printk("*******%s****1****n", __FUNCTION__);
tasklet_kill(&myvirtualdisk->mytasklet);//刪除任務(wù)
del_timer(&myvirtualdisk->mytimer);
printk("*******%s*****2***n", __FUNCTION__);
for(i = 0; i < 3; i++)free_irq(gpio_to_irq(myirq_descs[i].irq_id), &myirq_descs[i]);
printk("*******%s*****3***n", __FUNCTION__);
cdev_del(&myvirtualdisk->mycdev);
printk("*******%s*****4***n", __FUNCTION__);
class_device_unregister(myvirtualdisk->mycdevclassdevice);
printk("*******%s*****5***n", __FUNCTION__);
class_destroy(myvirtualdisk->mycdevclass);
printk("*******%s*****6***n", __FUNCTION__);
kfree(myvirtualdisk);
printk("*******%s********n", __FUNCTION__);
unregister_chrdev_region(MKDEV(major, 0), 1);
printk("*******%s*****7***n", __FUNCTION__);
}

module_init(cdevtest_init);
module_exit(cdevtest_exit);
MODULE_LICENSE("GPL");

完整的workqueue工作隊(duì)列中斷上下半部代碼

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

#include
#include
#include
#define VIRTUAL_MAJOR 250
int major = VIRTUAL_MAJOR;

struct myirq_desc{
int irq_id;
char *irq_name;
int irq_code;
};

struct myirq_desc myirq_descs[3]= {
{S3C2410_GPF0, "s2", KEY_J},
{S3C2410_GPF2, "s3", KEY_K},
{S3C2410_GPG3, "s4", KEY_Z},
};
struct VirtualDisk{
struct class *mycdevclass;//在/sys/class創(chuàng)建類
struct class_device *mycdevclassdevice;//在/dev下創(chuàng)建設(shè)備
struct cdev mycdev;//給設(shè)備添加相關(guān)的fileoption
struct timer_list mytimer;
struct tasklet_struct mytasklet;
struct workqueue_struct *myworkqueue;//工作隊(duì)列
struct work_struct mywork;//工作；工作隊(duì)列中的一項(xiàng)工作
};
struct VirtualDisk *myvirtualdisk;

static struct file_operations mydev_fops = {
.owner = THIS_MODULE,
};

static void mywork_func(struct work_struct *work){
printk("*******%s********n", __FUNCTION__);
}
static void mytasklet_func(unsigned long fundata){
printk("*****%s******,date = %ldn", __FUNCTION__, fundata);
}
static void mytimer_func(unsigned long fundata){
printk("*******%s********n", __FUNCTION__);
//struct VirtualDisk *myvirtualdisk_fun = (struct VirtualDisk *)(fundata);
//myvirtualdisk_fun->mytimer.expires =jiffies + 2 * HZ;
//add_timer(&myvirtualdisk_fun->mytimer);
printk("timer func happened!n");
}
static irqreturn_t myirq_handle(int irq, void *dev_id){
struct myirq_desc *myirq_descone = (struct myirq_desc *)dev_id;
printk("*******%s********n", __FUNCTION__);
printk("irq = %d, irq_id = %d,irq_name = %s, irq_code = %cn", irq, myirq_descone->irq_id, myirq_descone->irq_name, myirq_descone->irq_code);
queue_work(myvirtualdisk->myworkqueue, &myvirtualdisk->mywork);
tasklet_schedule(&myvirtualdisk->mytasklet);//激發(fā)任務(wù)，將mytasklet_func加入系統(tǒng)任務(wù)
mod_timer(&myvirtualdisk->mytimer, jiffies + 2*HZ);
return IRQ_RETVAL(IRQ_HANDLED);
}

static int __init cdevtest_init(void){
dev_t mydev = MKDEV(major, 0);
int ret;
int i = 0;
printk("*******%s********n", __FUNCTION__);
if(major){//注冊(cè)proc/devices
ret = register_chrdev_region(mydev, 1, "mynewdriver");
}else{
ret = alloc_chrdev_region(&mydev, 0, 1, "mynewdriver");
major = MAJOR(mydev);
}
if(ret < 0){
printk(KERN_ERR "register_chrdev_region failed!n");
ret = -EINVAL;
return ret;
}
myvirtualdisk = kmalloc(sizeof(struct VirtualDisk), GFP_KERNEL);
if(!myvirtualdisk){
ret = -ENOMEM;
printk(KERN_ERR "kmalloc myvirtualdisk failed!n");
goto release_chrdev;
}
myvirtualdisk->mycdevclass = class_create(THIS_MODULE, "mynewdriver");
if(IS_ERR(myvirtualdisk->mycdevclass)){
ret = PTR_ERR(myvirtualdisk->mycdevclass);
printk(KERN_ERR "class_create failed!n");
goto release_mem_malloc;

}
myvirtualdisk->mycdevclassdevice = class_device_create(myvirtualdisk->mycdevclass, NULL, MKDEV(major, 0), NULL, "mynewdriver");
if(IS_ERR(myvirtualdisk->mycdevclassdevice)){
ret = PTR_ERR(myvirtualdisk->mycdevclassdevice);
printk(KERN_ERR "class_device_create failed!n");
goto release_class_create;
}

//工作和工作隊(duì)列
INIT_WORK(&myvirtualdisk->mywork, mywork_func);
myvirtualdisk->myworkqueue = create_workqueue("myworkqueue");
if (!myvirtualdisk->myworkqueue) {
ret = -ENOMEM;
goto release_class_create;
}

cdev_init(&(myvirtualdisk->mycdev), &mydev_fops);
myvirtualdisk->mycdev.owner = THIS_MODULE;
ret = cdev_add(&myvirtualdisk->mycdev, MKDEV(major, 0), 1);

//tasklet 任務(wù)調(diào)度
tasklet_init(&myvirtualdisk->mytasklet, mytasklet_func, (unsigned long) 90);

//這里把timer相關(guān)的放在irq前面，不然會(huì)有bug出現(xiàn)(當(dāng)在insmod時(shí)候按下按鈕就會(huì)出錯(cuò))
init_timer(&myvirtualdisk->mytimer);
myvirtualdisk->mytimer.function = mytimer_func;
myvirtualdisk->mytimer.data = (unsigned long)myvirtualdisk;

if(ret < 0){
goto release_device_class_create;
}
for(i = 0; i < 3; i++)
{
ret = request_irq(gpio_to_irq(myirq_descs[i].irq_id), myirq_handle, IRQF_TRIGGER_FALLING, myirq_descs[i].irq_name, &myirq_descs[i]);
if(ret < 0){
printk(KERN_ERR "request irq failed!n");
ret =-EFAULT;
goto release_cdevandtimer;
}
}

/*在模塊注銷的時(shí)候，銷毀工作隊(duì)列和工作對(duì)象
void flush_workqueue(struct workqueue_struct * wq)
該函數(shù)會(huì)一直等待，知道指定的等待隊(duì)列中所有的任務(wù)都執(zhí)行完畢并從等待隊(duì)列中移除。
void destroy_workqueue(struct workqueue_struct * wq);
該函數(shù)是是創(chuàng)建等待隊(duì)列的反操作，注銷掉指定的等待隊(duì)列。*/

return 0;
release_cdevandtimer:
tasklet_kill(&myvirtualdisk->mytasklet);//刪除任務(wù)
del_timer(&myvirtualdisk->mytimer);
cdev_del(&myvirtualdisk->mycdev);
/*在模塊注銷的時(shí)候，銷毀工作隊(duì)列和工作對(duì)象
void flush_workqueue(struct workqueue_struct * wq)
該函數(shù)會(huì)一直等待，知道指定的等待隊(duì)列中所有的任務(wù)都執(zhí)行完畢并從等待隊(duì)列中移除。
void destroy_workqueue(struct workqueue_struct * wq);
該函數(shù)是是創(chuàng)建等待隊(duì)列的反操作，注銷掉指定的等待隊(duì)列。*/
flush_workqueue(myvirtualdisk->myworkqueue);
destroy_workqueue(myvirtualdisk->myworkqueue);
release_device_class_create:
class_device_unregister(myvirtualdisk->mycdevclassdevice);
release_class_create:
class_destroy(myvirtualdisk->mycdevclass);
release_mem_malloc:
kfree(myvirtualdisk);
release_chrdev:
unregister_chrdev_region(MKDEV(major, 0), 1);
return ret;
}

static void __exit cdevtest_exit(void){
int i = 0;
printk("*******%s****1****n", __FUNCTION__);
tasklet_kill(&myvirtualdisk->mytasklet);//刪除任務(wù)
del_timer(&myvirtualdisk->mytimer);
printk("*******%s*****2***n", __FUNCTION__);
for(i = 0; i < 3; i++)free_irq(gpio_to_irq(myirq_descs[i].irq_id), &myirq_descs[i]);
printk("*******%s*****3***n", __FUNCTION__);
cdev_del(&myvirtualdisk->mycdev);

//刪除工作和工作隊(duì)列
flush_workqueue(myvirtualdisk->myworkqueue);
destroy_workqueue(myvirtualdisk->myworkqueue);

printk("*******%s*****4***n", __FUNCTION__);
class_device_unregister(myvirtualdisk->mycdevclassdevice);
printk("*******%s*****5***n", __FUNCTION__);
class_destroy(myvirtualdisk->mycdevclass);
printk("*******%s*****6***n", __FUNCTION__);
kfree(myvirtualdisk);
printk("*******%s********n", __FUNCTION__);
unregister_chrdev_region(MKDEV(major, 0), 1);
printk("*******%s*****7***n", __FUNCTION__);
}

module_init(cdevtest_init);
module_exit(cdevtest_exit);
MODULE_LICENSE("GPL");