Linux设备驱动remap_pfn_range() 和remap_page_range()
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转载:http://blog.csdn.net/dijkstar/article/details/51347408
LDD3的开发环境推荐的是2.6.10,安装了RHEL4-update4,其内核版本为2.6.9.42,编译mmap的程序时报错:Unknown symbol remap_pfn_range
在网上查了下,应将上述报错的函数改为remap_page_range,并且remap_page_range不再推荐使用了,两个内核函数第二个参数定义不相同:
- int remap_page_range(struct vm_area_struct *vma,
- unsigned long from,
- unsigned long phys_addr,
- unsigned long size,
- pgprot_t prot)
-
-
- int remap_pfn_range(struct vm_area_struct *vma,
- unsigned long addr,
- unsigned long pfn,
- unsigned long size,
- pgprot_t prot)
直接看下面的一段程序,在注释中已经将两个函数的使用区分出来了。使用前,先mknod /dev/mymap c 60 0
- #include <linux/delay.h>
- #include <linux/kernel.h>
- #include <linux/module.h>
- #include <linux/init.h>
- #include <linux/mm.h>
- #include <linux/fs.h>
- #include <linux/types.h>
- #include <linux/delay.h>
- #include <linux/moduleparam.h>
- #include <linux/slab.h>
- #include <linux/errno.h>
- #include <linux/ioctl.h>
- #include <linux/cdev.h>
- #include <linux/string.h>
- #include <linux/list.h>
- #include <linux/pci.h>
-
-
-
- #define DEVICE_NAME "mymap"
-
-
- static unsigned char array[10]={0,1,2,3,4,5,6,7,8,9};
- static unsigned char *buffer;
-
-
- static int my_open(struct inode *inode, struct file *file)
- {
- return 0;
- }
-
-
- static int my_map(struct file *filp, struct vm_area_struct *vma)
- {
- unsigned long page;
- unsigned char i;
- unsigned long start = (unsigned long)vma->vm_start;
-
- unsigned long size = (unsigned long)(vma->vm_end - vma->vm_start);
-
-
- page = virt_to_phys(buffer);
-
-
- if(remap_page_range(vma,start,page,size,PAGE_SHARED))
- return -1;
-
-
- for(i=0;i<10;i++)
- buffer[i] = array[i];
-
- return 0;
- }
-
-
- static struct file_operations dev_fops = {
- .owner = THIS_MODULE,
- .open = my_open,
- .mmap = my_map,
- };
-
-
-
-
-
-
-
-
-
- static int __init dev_init(void)
- {
- int ret;
-
-
-
-
-
- ret = register_chrdev(60, DEVICE_NAME, &dev_fops);
- if (ret < 0)
- {
- printk("<1> memory: can't obtain major number %d\n", 60);
- return ret;
- }
-
-
-
- buffer = (unsigned char *)kmalloc(PAGE_SIZE,GFP_KERNEL);
-
- SetPageReserved(virt_to_page(buffer));
-
- return ret;
- }
-
-
- static void __exit dev_exit(void)
- {
-
-
- unregister_chrdev(60, DEVICE_NAME);
-
-
-
- ClearPageReserved(virt_to_page(buffer));
-
- kfree(buffer);
- }
-
-
- module_init(dev_init);
- module_exit(dev_exit);
- MODULE_LICENSE("Dual BSD/GPL");
应用程序:
- #include <unistd.h>
- #include <stdio.h>
- #include <stdlib.h>
- #include <string.h>
- #include <fcntl.h>
- #include <linux/fb.h>
- #include <sys/mman.h>
- #include <sys/ioctl.h>
-
- #define PAGE_SIZE 4096
-
-
- int main(int argc , char *argv[])
- {
- int fd;
- int i;
- unsigned char *p_map;
-
-
- fd = open("/dev/mymap",O_RDWR);
- if(fd < 0)
- {
- printf("open fail\n");
- exit(1);
- }
-
-
- p_map = (unsigned char *)mmap(0, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,fd, 0);
- if(p_map == MAP_FAILED)
- {
- printf("mmap fail\n");
- goto here;
- }
-
-
- for(i=0;i<10;i++)
- printf("%d\n",p_map[i]);
-
-
- here:
- munmap(p_map, PAGE_SIZE);
- return 0;
- }
makefile文件:
- obj-m := testdrv.o
- PWD := $(shell pwd)
- all:
- make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules
- clean:
- rm -rf *.o *~ core .*.cmd *.mod.c ./tmp_version