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目录
硬件有一个时钟装置,该装置每隔一定时间发出一个时钟中断(称为一次时钟嘀嗒-tick),对应的中断处理程序就将全局变量jiffies_64加1
jiffies_64 是一个全局64位整型, jiffies全局变量为其低32位的全局变量,程序中一般用jiffies
HZ:可配置的宏,表示1秒钟产生的时钟中断次数,一般设为100或200
短延迟:忙等待
- 1. void ndelay(unsigned long nsecs)
- 2. void udelay(unsigned long usecs)
- 3. void mdelay(unsigned long msecs)
长延迟:忙等待
使用jiffies比较宏来实现
- time_after(a,b) //a > b
- time_before(a,b) //a < b
-
- //延迟100个jiffies
- unsigned long delay = jiffies + 100;
- while(time_before(jiffies,delay))
- {
- ;
- }
-
- //延迟2s
- unsigned long delay = jiffies + 2*HZ;
- while(time_before(jiffies,delay))
- {
- ;
- }
睡眠延迟----阻塞类
- void msleep(unsigned int msecs);
-
- unsigned long msleep_interruptible(unsigned int msecs);
延时机制的选择原则:
(1)定义定时器结构体
- struct timer_list
- {
- struct list_head entry;
- unsigned long expires; // 期望的时间值 jiffies + x * HZ
- void (*function)(unsigned long); // 时间到达后,执行的回调函数,软中断异常上下文
- unsigned long data;
- };
(2)初始化定时器
init_timer(struct timer_list *)
(3)增加定时器 ------ 定时器开始计时
void add_timer(struct timer_list *timer);
(4)删除定时器 -------定时器停止工作
int del_timer(struct timer_list * timer);
(5)修改定时器
int mod_timer(struct timer_list *timer, unsigned long expires);
- 定义struct timer_list tl类型的变量
-
-
- init_timer(...);//模块入口函数
-
- //模块入口函数或open或希望定时器开始工作的地方
- tl.expires = jiffies + n * HZ //n秒
- tl.function = xxx_func;
- tl.data = ...;
-
- add_timer(....);
-
-
- //不想让定时器继续工作时
- del_timer(....);
-
- void xxx_func(unsigned long arg)
- {
- ......
- mod_timer(....);//如需要定时器继续隔指定时间再次调用本函数
- }
- #include <linux/module.h>
- #include <linux/kernel.h>
- #include <linux/fs.h>
- #include <linux/cdev.h>
- #include <linux/wait.h>
- #include <linux/device.h>
- #include <linux/sched.h>
- #include <linux/poll.h>
- #include <asm/uaccess.h>
- #include <asm/atomic.h>
-
-
- int major = 11;
- int minor = 0;
- int mysecond_num = 1;
-
- struct mysecond_dev
- {
- struct cdev mydev;
-
- int second;
- struct timer_list timer;
-
- atomic_t openflag;//1 can open, 0 can not open
-
- struct class *pcls;
- struct device *pdev;
- };
-
- struct mysecond_dev gmydev;
-
- void timer_func(unsigned long arg)
- {
- struct mysecond_dev *pmydev = (struct mysecond_dev *)arg;
-
- pmydev->second++;
-
- mod_timer(&pmydev->timer,jiffies + HZ * 1);
- }
-
- int mysecond_open(struct inode *pnode,struct file *pfile)
- {
- struct mysecond_dev *pmydev = NULL;
-
- pfile->private_data =(void *) (container_of(pnode->i_cdev,struct mysecond_dev,mydev));
-
- pmydev = (struct mysecond_dev *)pfile->private_data;
-
- if(atomic_dec_and_test(&pmydev->openflag))
- {
-
- pmydev->timer.expires = jiffies + HZ * 1;
- pmydev->timer.function = timer_func;
- pmydev->timer.data = (unsigned long)pmydev;
-
- add_timer(&pmydev->timer);
-
- return 0;
- }
- else
- {
- atomic_inc(&pmydev->openflag);
- printk("The device is opened already\n");
- return -1;
- }
- }
-
- int mysecond_close(struct inode *pnode,struct file *pfile)
- {
- struct mysecond_dev *pmydev = (struct mysecond_dev *)pfile->private_data;
-
- del_timer(&pmydev->timer);
-
- atomic_set(&pmydev->openflag,1);
- return 0;
- }
-
- ssize_t mysecond_read(struct file *pfile,char __user *puser,size_t size,loff_t *p_pos)
- {
- struct mysecond_dev *pmydev = (struct mysecond_dev *)pfile->private_data;
- int ret = 0;
-
- if(size < sizeof(int))
- {
- printk("the expect read size is invalid\n");
- return -1;
- }
-
- if(size >= sizeof(int))
- {
- size = sizeof(int);
- }
-
- ret = copy_to_user(puser,&pmydev->second,size);
- if(ret)
- {
- printk("copy to user failed\n");
- return -1;
- }
- return size;
- }
-
- struct file_operations myops = {
- .owner = THIS_MODULE,
- .open = mysecond_open,
- .release = mysecond_close,
- .read = mysecond_read,
- };
-
- int __init mysecond_init(void)
- {
- int ret = 0;
- dev_t devno = MKDEV(major,minor);
-
- /*申请设备号*/
- ret = register_chrdev_region(devno,mysecond_num,"mysecond");
- if(ret)
- {
- ret = alloc_chrdev_region(&devno,minor,mysecond_num,"mysecond");
- if(ret)
- {
- printk("get devno failed\n");
- return -1;
- }
- major = MAJOR(devno);//容易遗漏,注意
- }
-
- /*给struct cdev对象指定操作函数集*/
- cdev_init(&gmydev.mydev,&myops);
-
- /*将struct cdev对象添加到内核对应的数据结构里*/
- gmydev.mydev.owner = THIS_MODULE;
- cdev_add(&gmydev.mydev,devno,mysecond_num);
-
- init_timer(&gmydev.timer);
-
- atomic_set(&gmydev.openflag,1);
-
- gmydev.pcls = class_create(THIS_MODULE,"mysecond");
- if(IS_ERR(gmydev.pcls))
- {
- printk("class_create failed\n");
- cdev_del(&gmydev.mydev);
- unregister_chrdev_region(devno,mysecond_num);
- return -1;
- }
-
- gmydev.pdev = device_create(gmydev.pcls,NULL,devno,NULL,"mysec");
- if(NULL == gmydev.pdev)
- {
- printk("device_create failed\n");
- class_destroy(gmydev.pcls);
- cdev_del(&gmydev.mydev);
- unregister_chrdev_region(devno,mysecond_num);
- return -1;
- }
- return 0;
- }
-
- void __exit mysecond_exit(void)
- {
- dev_t devno = MKDEV(major,minor);
-
- device_destroy(gmydev.pcls,devno);
- class_destroy(gmydev.pcls);
-
- cdev_del(&gmydev.mydev);
-
- unregister_chrdev_region(devno,mysecond_num);
- }
-
-
- MODULE_LICENSE("GPL");
-
- module_init(mysecond_init);
- module_exit(mysecond_exit);
应用层:
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <fcntl.h>
- #include <unistd.h>
-
-
- #include <stdio.h>
-
- int main(int argc,char *argv[])
- {
- int fd = -1;
- int sec = 0;
-
- if(argc < 2)
- {
- printf("The argument is too few\n");
- return 1;
- }
-
- fd = open(argv[1],O_RDONLY);
- if(fd < 0)
- {
- printf("open %s failed\n",argv[1]);
- return 2;
- }
-
- sleep(3);
-
- read(fd,&sec,sizeof(sec));
- printf("The second is %d\n",sec);
-
- close(fd);
- fd = -1;
- return 0;
- }
内核将物理内存等分成N块4KB,称之为一页,每页都用一个struct page来表示,采用伙伴关系算法维护
内核地址空间划分图:
3G~3G+896M:低端内存,直接映射 虚拟地址 = 3G + 物理地址
细分为:ZONE_DMA、ZONE_NORMAL
分配方式:
- 1. kmalloc:小内存分配,slab算法
- 2. get_free_page:整页分配,2的n次方页,n最大为10
大于3G+896M:高端内存
细分为:vmalloc区、持久映射区、固定映射区
分配方式:vmalloc:虚拟地址连续,物理地址不连续
函数原型:
void *kmalloc(size_t size, gfp_t flags);
kmalloc() 申请的内存位于直接映射区域,而且在物理上也是连续的,它们与真实的物理地址只有一个固定的偏移,因为存在较简单的转换关系,所以对申请的内存大小有限制,不能超过128KB。 较常用的 flags(分配内存的方法):
flags 的参考用法:
|– 进程上下文,可以睡眠 GFP_KERNEL
|– 异常上下文,不可以睡眠 GFP_ATOMIC
| |– 中断处理程序 GFP_ATOMIC
| |– 软中断 GFP_ATOMIC
| |– Tasklet GFP_ATOMIC
|– 用于DMA的内存,可以睡眠 GFP_DMA | GFP_KERNEL
|– 用于DMA的内存,不可以睡眠 GFP_DMA |GFP_ATOMIC
对应的内存释放函数为:
void kfree(const void *objp);
void *kzalloc(size_t size, gfp_t flags)
void *vmalloc(unsigned long size);
vmalloc() 函数则会在虚拟内存空间给出一块连续的内存区,但这片连续的虚拟内存在物理内存中并不一定连续。由于 vmalloc() 没有保证申请到的是连续的物理内存,因此对申请的内存大小没有限制,如果需要申请较大的内存空间就需要用此函数了。
对应的内存释放函数为:
void vfree(const void *addr);
注意:vmalloc() 和 vfree() 可以睡眠,因此不能从异常上下文调用。
kmalloc()、kzalloc()、vmalloc() 的共同特点是:
kmalloc()、kzalloc()、vmalloc() 的区别是:
一般情况下,内存只有在要被 DMA 访问的时候才需要物理上连续,但为了性能上的考虑,内核中一般使用 kmalloc(),而只有在需要获得大块内存时才使用 vmalloc()。
- #include <linux/module.h>
- #include <linux/kernel.h>
- #include <linux/fs.h>
- #include <linux/cdev.h>
- #include <linux/uaccess.h>
- #include <linux/wait.h>
- #include <linux/sched.h>
- #include <linux/poll.h>
- #include <linux/mm.h>
- #include <linux/slab.h>
- #include "mychar.h"
-
- #define BUF_LEN 100
-
- int major = 11;
- int minor = 0;
- int mychar_num = 1;
-
- struct mychar_dev
- {
- struct cdev mydev;
- char mydev_buf[BUF_LEN];
- int curlen;
-
- struct mutex lock;
-
- /*Read wait queue and write wait queue*/
- wait_queue_head_t rq;
- wait_queue_head_t wq;
-
- struct fasync_struct *pasync_obj;
- };
-
- struct mychar_dev *pgmydev = NULL;
-
- int mychar_open(struct inode *pnode, struct file *pfile)
- {
- pfile->private_data = container_of(pnode->i_cdev, struct mychar_dev, mydev);
- printk("mychar_open\n");
- return 0;
- }
- int mychar_close(struct inode *pnode, struct file *pfile)
- {
- //printk("mychar_close\n");
- /*C90 requires printk after the variable declaration*/
- struct mychar_dev *pmydev = (struct mychar_dev *)pfile->private_data;
-
- if(pmydev->pasync_obj != NULL)
- fasync_helper(-1,pfile,0, &pmydev->pasync_obj);
- return 0;
- }
-
- ssize_t mychar_read(struct file *pfile, char __user *puser, size_t count, loff_t *p_pos)
- {
- struct mychar_dev *pmydev = (struct mychar_dev *)pfile->private_data;
- int size = 0;
- int ret = 0;
-
- mutex_lock(&pmydev->lock);
- if(pmydev->curlen <= 0)
- {
- if(pfile->f_flags & O_NONBLOCK)
- {//non-blocking
- mutex_unlock(&pmydev->lock);
- printk("O_NONBLOCK No Data Read\n");
- return -1;
- }
- else
- {//blocking
- mutex_unlock(&pmydev->lock);
- ret = wait_event_interruptible(pmydev->rq,pmydev->curlen > 0);
- if(ret)
- {
- printk("Wake up by signal\n");
- return -ERESTARTSYS;
- }
- mutex_lock(&pmydev->lock);
- }
- }
-
- if(count > pmydev->curlen)
- {
- size = pmydev->curlen;
- }
- else
- {
- size = count;
- }
-
- ret = copy_to_user(puser, pmydev->mydev_buf, size);
- if(ret)
- {
- mutex_unlock(&pmydev->lock);
- printk("copy_to_user failed\n");
- return -1;
- }
-
- memcpy(pmydev->mydev_buf, pmydev->mydev_buf + size, pmydev->curlen - size);
-
- pmydev->curlen = pmydev->curlen - size;
-
- mutex_unlock(&pmydev->lock);
- /*Wake up interrupt*/
- wake_up_interruptible(&pmydev->wq);
- return size;
- }
- ssize_t mychar_write(struct file *pfile, const char __user *puser, size_t count, loff_t *p_pos)
- {
- int size = 0;
- int ret = 0;
- struct mychar_dev *pmydev = (struct mychar_dev *)pfile->private_data;
-
- mutex_lock(&pmydev->lock);
- if(pmydev->curlen >= BUF_LEN)
- {
- if(pfile->f_flags & O_NONBLOCK)
- {
- mutex_unlock(&pmydev->lock);
- printk("O_NONBLOCK can not write\n");
- return -1;
- }
- else
- {
- mutex_unlock(&pmydev->lock);
- ret = wait_event_interruptible(pmydev->wq,
- pmydev->curlen < BUF_LEN);
- if(ret)
- {
- printk("wake up by signal\n");
- return -ERESTARTSYS;
- }
- mutex_lock(&pmydev->lock);
- }
- }
-
- if(count > BUF_LEN - pmydev->curlen)
- {
- size = BUF_LEN - pmydev->curlen;
- }
- else
- {
- size = count;
- }
-
- ret = copy_from_user(pmydev->mydev_buf + pmydev->curlen, puser, size);
- if(ret)
- {
- mutex_unlock(&pmydev->lock);
- printk("copy_from_user failed\n");
- return -1;
- }
- pmydev->curlen += size;
-
- mutex_unlock(&pmydev->lock);
- /*Wake up interrupt*/
- wake_up_interruptible(&pmydev->rq);
-
- if(pmydev->pasync_obj != NULL)
- {
- kill_fasync(&pmydev->pasync_obj, SIGIO, POLL_IN);
- }
- return size;
- }
-
- long mychar_ioctl(struct file *pfile, unsigned int cmd, unsigned long arg)
- {
- int __user *pret = (int *)arg;
- int maxlen = BUF_LEN;
- int ret = 0;
- struct mychar_dev *pmydev = (struct mychar_dev *)pfile->private_data;
-
-
- switch(cmd)
- {
- case MYCHAR_IOCTL_GET_MAXLEN:
- ret = copy_to_user(pret, &maxlen, sizeof(int));
- if(ret)
- {
- printk("copy_to_user MAXLEN failed\n");
- return -1;
- }
- break;
- case MYCHAR_IOCTL_GET_CURLEN:
- mutex_lock(&pmydev->lock);
- ret = copy_to_user(pret, &pmydev->curlen, sizeof(int));
- mutex_unlock(&pmydev->lock);
- if(ret)
- {
- printk("copy_to_user MAXLEN failed\n");
- return -1;
- }
- break;
- default:
- printk("The cmd is unknow\n");
- return -1;
- }
- return 0;
- }
-
- unsigned int mychar_poll(struct file *pfile, poll_table *ptb)
- {
- struct mychar_dev *pmydev = (struct mychar_dev *)pfile->private_data;
- unsigned int mask = 0;
-
- /*It not block. Adds the wait queue to the table*/
- poll_wait(pfile,&pmydev->rq,ptb);
- poll_wait(pfile,&pmydev->wq,ptb);
-
- mutex_lock(&pmydev->lock);
- if(pmydev->curlen > 0)
- {
- mask |= POLLIN | POLLRDNORM;
- }
- if(pmydev->curlen < BUF_LEN)
- {
- mask |= POLLOUT | POLLWRNORM;
- }
- mutex_unlock(&pmydev->lock);
- return mask;
-
- }
-
- int mychar_fasync(int fd,struct file *pfile, int mode)
- {
- struct mychar_dev *pmydev = (struct mychar_dev *)pfile->private_data;
-
- return fasync_helper(fd, pfile, mode, &pmydev->pasync_obj);
- }
- struct file_operations myops = {
- .owner = THIS_MODULE,
- .open = mychar_open,
- .release = mychar_close,
- .read = mychar_read,
- .write = mychar_write,
- .unlocked_ioctl = mychar_ioctl,
- .poll = mychar_poll,
- .fasync = mychar_fasync,
- };
-
-
- int __init mychar_init(void)
- {
- int ret = 0;
- dev_t devno = MKDEV(major,minor);
-
- /*Apply for device number*/
- ret = register_chrdev_region(devno, mychar_num, "mychar");
- if(ret)
- {
- ret = alloc_chrdev_region(&devno, minor, mychar_num, "mychar");
- if(ret)
- {
- printk("get devno failed\n");
- return -1;
- }
- printk("copy_to_user failed\n");
- major = MAJOR(devno);//Easy to miss *****
- }
-
- pgmydev = (struct mychar_dev *)kmalloc(sizeof(struct mychar_dev), GFP_KERNEL);
- if(NULL == pgmydev)
- {
- unregister_chrdev_region(devno, mychar_num);
- printk("kmallc for struct mychar_dev failed\n");
- return -1;
- }
-
- /*Assign the 'struct cdev' a set of operation functions*/
- cdev_init(&pgmydev->mydev, &myops);
- /*Add 'struct cdev' to the kernel's data structure*/
- pgmydev->mydev.owner = THIS_MODULE;
- cdev_add(&pgmydev->mydev, devno, mychar_num);//add to Hash.
-
- /*initialize the wait queue header*/
- init_waitqueue_head(&pgmydev->rq);
- init_waitqueue_head(&pgmydev->wq);
-
- mutex_init(&pgmydev->lock);
- return 0;
- }
- void __exit mychar_exit(void)
- {
- dev_t devno = MKDEV(major,minor);
- cdev_del(&pgmydev->mydev);
- //printk("mychar will exit\n");
- unregister_chrdev_region(devno, mychar_num);
- kfree(pgmydev);
- pgmydev = NULL;
- }
- MODULE_LICENSE("GPL");
-
- module_init(mychar_init);
- module_exit(mychar_exit);
CPU不会直接和外设连接,需要经过一个对应的控制器,卡状的就叫适配器,芯片状的就叫控制器。外设直接和SOC上的控制器连接的叫一级外设。挂在总线上的叫二级外设。
两种方式:
IO内存访问接口:
- static inline void __iomem *ioremap(unsigned long offset, unsigned long size)
- /*
- 功能:实现IO管脚的映射
- 参数:offset:该管脚的偏移地址
- Size:该管脚映射空间的大小
- 返回值:成功返回映射的虚拟地址,失败NULL
- */
-
- static inline void iounmap(volatile void __iomem *addr)
- /*
- 功能:解除io管脚的映射
- 参数:addr:io管脚映射的地址
- */
-
- unsigned readb(void *addr);//1字节 或ioread8(void *addr)
- unsigned readw(void *addr);//2字节 或ioread16(void *addr)
- unsigned readl(void *addr);//4字节 或ioread32(void *addr)
- /*
- 功能:读取寄存器的值
- 参数:addr 地址
- 返回值:读到的数据
- */
-
- void writeb(unsigned value, void *addr);//1字节 或iowrite8(u8 value, void *addr)
- void writew(unsigned value, void *addr);//2字节 或iowrite16(u16 value, void *addr)
- void writel(unsigned value, void *addr);//4字节 或iowrite32(u32 value, void *addr)
- /*
- 功能:向指定的寄存器中,写入数据。
- 参数:value:待写入寄存器中的数据
- Address:寄存器的虚拟地址
- */
读原理图
查阅SOC芯片手册
GPX2_7 led2 GPX2CON----0x11000C40---28~31-----0001 GPX2DAT-----0x11000C44-----7
GPX1_0 led3 GPX1CON----0x11000C20---0~3-----0001 GPX1DAT----0x11000C24-----0
GPF3_4 led4 GPF3CON----0x114001E0---16~19-----0001 GPF3DAT----0x114001E4-----4
GPF3_5 led5 GPF3CON----0x114001E0---20~23-----0001 GPF3DAT----0x114001E4-----5
编写驱动
a. 设计设备数据类型
- struct myled_dev
- {
- struct cdev mydev;
-
- unsigned long * led2con;
- unsigned long * led2dat;
-
- unsigned long * led3con;
- unsigned long * led3dat;
-
- unsigned long * led4con;
- unsigned long * led4dat;
-
- unsigned long * led5con;
- unsigned long * led5dat;
- };
b. 考虑需要支持的函数
c. 模块入口:ioremap + 设置成输出
d. 模块出口:iounmap
e. 编写关灯函数和开灯函数,实现ioctl
volatile:对指针指向的空间不做任何优化,不加这个关键字会把指针的值放到cpu的寄存器中,加快访问速度。加上这个关键字会阻止这种优化。
leddrv.h
- #ifndef LED_DRIVER_H
- #define LED_DRIVER_H
-
- #define LED_DEV_MAGIC 'g'
-
- #define MY_LED_OFF _IO(LED_DEV_MAGIC,0)
- #define MY_LED_ON _IO(LED_DEV_MAGIC,1)
-
-
-
- #endif
leddrv.c
- #include <linux/module.h>
- #include <linux/kernel.h>
- #include <linux/fs.h>
- #include <linux/cdev.h>
- #include <linux/wait.h>
- #include <linux/sched.h>
- #include <linux/poll.h>
- #include <linux/slab.h>
- #include <linux/mm.h>
- #include <linux/io.h>
- #include <asm/uaccess.h>
- #include <asm/atomic.h>
-
- #include "leddrv.h"
-
- #define GPX1CON 0x11000C20
- #define GPX1DAT 0x11000C24
-
- #define GPX2CON 0x11000C40
- #define GPX2DAT 0x11000C44
-
- #define GPF3CON 0x114001E0
- #define GPF3DAT 0x114001E4
-
-
- int major = 11;
- int minor = 0;
- int myled_num = 1;
-
- struct myled_dev
- {
- struct cdev mydev;
-
- volatile unsigned long *pled2_con;
- volatile unsigned long *pled2_dat;
-
- volatile unsigned long *pled3_con;
- volatile unsigned long *pled3_dat;
-
- volatile unsigned long *pled4_con;
- volatile unsigned long *pled4_dat;
-
- volatile unsigned long *pled5_con;
- volatile unsigned long *pled5_dat;
- };
-
- struct myled_dev *pgmydev = NULL;
-
-
- int myled_open(struct inode *pnode,struct file *pfile)
- {
- pfile->private_data =(void *) (container_of(pnode->i_cdev,struct myled_dev,mydev));
-
- return 0;
- }
-
- int myled_close(struct inode *pnode,struct file *pfile)
- {
- return 0;
- }
-
- void led_on(struct myled_dev *pmydev,int ledno)
- {
- switch(ledno)
- {
- case 2:
- writel(readl(pmydev->pled2_dat) | (0x1 << 7),pmydev->pled2_dat);
- break;
- case 3:
- writel(readl(pmydev->pled3_dat) | (0x1),pmydev->pled3_dat);
- break;
- case 4:
- writel(readl(pmydev->pled4_dat) | (0x1 << 4),pmydev->pled4_dat);
- break;
- case 5:
- writel(readl(pmydev->pled5_dat) | (0x1 << 5),pmydev->pled5_dat);
- break;
- }
- }
-
- void led_off(struct myled_dev *pmydev,int ledno)
- {
- switch(ledno)
- {
- case 2:
- writel(readl(pmydev->pled2_dat) & (~(0x1 << 7)),pmydev->pled2_dat);
- break;
- case 3:
- writel(readl(pmydev->pled3_dat) & (~(0x1)),pmydev->pled3_dat);
- break;
- case 4:
- writel(readl(pmydev->pled4_dat) & (~(0x1 << 4)),pmydev->pled4_dat);
- break;
- case 5:
- writel(readl(pmydev->pled5_dat) & (~(0x1 << 5)),pmydev->pled5_dat);
- break;
- }
- }
-
-
- long myled_ioctl(struct file *pfile,unsigned int cmd,unsigned long arg)
- {
- struct myled_dev *pmydev = (struct myled_dev *)pfile->private_data;
-
- if(arg < 2 || arg > 5)
- {
- return -1;
- }
- switch(cmd)
- {
- case MY_LED_ON:
- led_on(pmydev,arg);
- break;
- case MY_LED_OFF:
- led_off(pmydev,arg);
- break;
- default:
- return -1;
- }
-
- return 0;
- }
-
- struct file_operations myops = {
- .owner = THIS_MODULE,
- .open = myled_open,
- .release = myled_close,
- .unlocked_ioctl = myled_ioctl,
- };
-
- void ioremap_ledreg(struct myled_dev *pmydev)
- {
- pmydev->pled2_con = ioremap(GPX2CON,4);
- pmydev->pled2_dat = ioremap(GPX2DAT,4);
-
- pmydev->pled3_con = ioremap(GPX1CON,4);
- pmydev->pled3_dat = ioremap(GPX1DAT,4);
-
- pmydev->pled4_con = ioremap(GPF3CON,4);
- pmydev->pled4_dat = ioremap(GPF3DAT,4);
-
- pmydev->pled5_con = pmydev->pled4_con;
- pmydev->pled5_dat = pmydev->pled4_dat;
- }
-
- void set_output_ledconreg(struct myled_dev *pmydev)
- {
- writel((readl(pmydev->pled2_con) & (~(0xF << 28))) | (0x1 << 28),pmydev->pled2_con);
- writel((readl(pmydev->pled3_con) & (~(0xF))) | (0x1),pmydev->pled3_con);
- writel((readl(pmydev->pled4_con) & (~(0xF << 16))) | (0x1 << 16),pmydev->pled4_con);
- writel((readl(pmydev->pled5_con) & (~(0xF << 20))) | (0x1 << 20),pmydev->pled5_con);
-
- writel(readl(pmydev->pled2_dat) & (~(0x1 << 7)),pmydev->pled2_dat);
- writel(readl(pmydev->pled3_dat) & (~(0x1)),pmydev->pled3_dat);
- writel(readl(pmydev->pled4_dat) & (~(0x1 << 4)),pmydev->pled4_dat);
- writel(readl(pmydev->pled5_dat) & (~(0x1 << 5)),pmydev->pled5_dat);
- }
-
- void iounmap_ledreg(struct myled_dev *pmydev)
- {
- iounmap(pmydev->pled2_con);
- pmydev->pled2_con = NULL;
- iounmap(pmydev->pled2_dat);
- pmydev->pled2_dat = NULL;
-
- iounmap(pmydev->pled3_con);
- pmydev->pled3_con = NULL;
- iounmap(pmydev->pled3_dat);
- pmydev->pled3_dat = NULL;
-
- iounmap(pmydev->pled4_con);
- pmydev->pled4_con = NULL;
- iounmap(pmydev->pled4_dat);
- pmydev->pled4_dat = NULL;
-
- pmydev->pled5_con = NULL;
- pmydev->pled5_dat = NULL;
- }
-
- int __init myled_init(void)
- {
- int ret = 0;
- dev_t devno = MKDEV(major,minor);
-
- /*申请设备号*/
- ret = register_chrdev_region(devno,myled_num,"myled");
- if(ret)
- {
- ret = alloc_chrdev_region(&devno,minor,myled_num,"myled");
- if(ret)
- {
- printk("get devno failed\n");
- return -1;
- }
- major = MAJOR(devno);//容易遗漏,注意
- }
-
- pgmydev = (struct myled_dev *)kmalloc(sizeof(struct myled_dev),GFP_KERNEL);
- if(NULL == pgmydev)
- {
- unregister_chrdev_region(devno,myled_num);
- printk("kmalloc failed\n");
- return -1;
- }
- memset(pgmydev,0,sizeof(struct myled_dev));
-
- /*给struct cdev对象指定操作函数集*/
- cdev_init(&pgmydev->mydev,&myops);
-
- /*将struct cdev对象添加到内核对应的数据结构里*/
- pgmydev->mydev.owner = THIS_MODULE;
- cdev_add(&pgmydev->mydev,devno,myled_num);
-
- /*ioremap*/
- ioremap_ledreg(pgmydev);
-
- /*con-register set output*/
- set_output_ledconreg(pgmydev);
-
- return 0;
- }
-
- void __exit myled_exit(void)
- {
- dev_t devno = MKDEV(major,minor);
-
- /*iounmap*/
- iounmap_ledreg(pgmydev);
-
- cdev_del(&pgmydev->mydev);
-
- unregister_chrdev_region(devno,myled_num);
-
- kfree(pgmydev);
- pgmydev = NULL;
- }
-
-
- MODULE_LICENSE("GPL");
-
- module_init(myled_init);
- module_exit(myled_exit);
testled.c
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <fcntl.h>
- #include <sys/ioctl.h>
- #include <unistd.h>
-
- #include <stdio.h>
-
- #include "leddrv.h"
-
- int main(int argc,char *argv[])
- {
- int fd = -1;
- int onoff = 0;
- int no = 0;
-
- if(argc < 4)
- {
- printf("The argument is too few\n");
- return 1;
- }
-
- sscanf(argv[2],"%d",&onoff);
- sscanf(argv[3],"%d",&no);
-
- if(no < 2 || no > 5)
- {
- printf("len-no is invalid\n");
- return 2;
- }
-
- fd = open(argv[1],O_RDONLY);
- if(fd < 0)
- {
- printf("open %s failed\n",argv[1]);
- return 3;
- }
-
- if(onoff)
- {
- ioctl(fd,MY_LED_ON,no);
- }
- else
- {
- ioctl(fd,MY_LED_OFF,no);
- }
-
- close(fd);
- fd = -1;
- return 0;
- }
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