linux 驱动mmap

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/mm.h>

static int device_open(struct inode *inode, struct file *file) {
    // 设备打开时的操作
}

static int device_release(struct inode *inode, struct file *file) {
    // 设备关闭时的操作
}

static ssize_t device_read(struct file *file, char __user *buffer, size_t length, loff_t *offset) {
    // 设备读取操作
}

static ssize_t device_write(struct file *file, const char __user *buffer, size_t length, loff_t *offset) {
    // 设备写入操作
}

static int device_mmap(struct file *file, struct vm_area_struct *vma) {
    unsigned long page;
    unsigned long size = vma->vm_end - vma->vm_start;

    // 分配内存页
    page = __get_free_pages(GFP_KERNEL, 0);
    if (!page) {
        return -ENOMEM;
    }

    // 设置内存区域属性
    vma->vm_flags |= VM_IO;
    vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

    // 建立映射关系
    if (remap_pfn_range(vma, vma->vm_start, page >> PAGE_SHIFT, size, vma->vm_page_prot)) {
        free_pages(page, 0);
        return -EAGAIN;
    }

    return 0;
}

static struct file_operations fops = {
    .owner = THIS_MODULE,
    .open = device_open,
    .release = device_release,
    .read = device_read,
    .write = device_write,
    .mmap = device_mmap,
};

// 其他驱动注册和注销代码...