2017-2018-1 20155211 实验四 外设驱动程序设计
2017-12-03 14:28
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实验步骤
4-1
学习资源中全课中的“hqyj.嵌入式Linux应用程序开发标准教程.pdf”中的第十一章提交康奈尔笔记的照片(可以多张)
4-2
在Ubuntu完成资源中全课中的“hqyj.嵌入式Linux应用程序开发标准教程.pdf”中的第十一章的test试验提交编译,加载模块,卸载模块,测试运行的截图(体现学号信息)
实验代码
/* test_drv.c */include <linux/module.h>
include <linux/init.h>
include <linux/fs.h>
include <linux/kernel.h>
include <linux/slab.h>
include <linux/types.h>
include <linux/errno.h>
include <linux/cdev.h>
include <asm/uaccess.h>
define TEST_DEVICE_NAME "test_dev"
define BUFF_SZ 1024
static struct cdev test_dev; unsigned int major =0; static char *data = NULL; static ssize_t test_read(struct file file, char buf, size_t count, loff_t *f_pos); static ssize_t test_write(struct file file,const char buffer, size_t count,loff_t *f_pos); static int test_open(struct inode inode, struct file file); static int test_release(struct inode inode,struct file file); static ssize_t test_read(struct file file, char buf, size_t count, loff_t *f_pos) {int len; if (count < 0 ) { return -EINVAL; } len = strlen(data); count = (len > count)?count:len; if (copy_to_user(buf, data, count)) { return -EFAULT; } return count;
}static ssize_t test_write(struct file file, const char buffer, size_t count, loff_t *f_pos)
{
[code]if(count < 0)
{
return -EINVAL;
}memset(data, 0, BUFF_SZ);
count = (BUFF_SZ > count)?count:BUFF_SZ;
if (copy_from_user(data, buffer, count))
{
return -EFAULT;
}return count;
}static int test_open(struct inode inode, struct file file)
{
printk("This is open operation\n"); data = (char*)kmalloc(sizeof(char) * BUFF_SZ, GFP_KERNEL); if (!data) { return -ENOMEM; } memset(data, 0, BUFF_SZ); return 0;
}static int test_release(struct inode inode,struct file file)
{
printk("This is release operation\n");
if (data)
{
kfree(data); data = NULL; } return 0;
}static void test_setup_cdev(struct cdev *dev, int minor,
struct file_operations *fops)
{
int err, devno = MKDEV(major, minor); cdev_init(dev, fops); dev->owner = THIS_MODULE; dev->ops = fops; err = cdev_add (dev, devno, 1); if (err) { printk (KERN_NOTICE "Error %d adding test %d", err, minor); }
}static struct file_operations test_fops =
{
.owner = THIS_MODULE, .read = test_read, .write = test_write, .open = test_open, .release = test_release,
};
int init_module(void)
{
int result; dev_t dev = MKDEV(major, 0); if (major) { result = register_chrdev_region(dev, 1, TEST_DEVICE_NAME); } else { result = alloc_chrdev_region(&dev, 0, 1, TEST_DEVICE_NAME); major = MAJOR(dev); } if (result < 0) { printk(KERN_WARNING "Test device: unable to get major %d\n", major); return result; } test_setup_cdev(&test_dev, 0, &test_fops); printk("The major of the test device is %d\n", major); return 0;
}void cleanup_module(void)
{
cdev_del(&test_dev); unregister_chrdev_region(MKDEV(major, 0), 1); printk("Test device uninstalled\n");
[/code]
}
test.c代码如下:
/* test.c */
include
include
include
include <sys/stat.h>
include <sys/types.h>
include
include
define TEST_DEVICE_FILENAME "/dev/test_dev"
define BUFF_SZ 1024
int main()
{int fd, nwrite, nread;
char buff[BUFF_SZ];
fd = open(TEST_DEVICE_FILENAME, O_RDWR);
if (fd < 0)
{
perror("open");
exit(1);
}do
{
printf("Input some words to kernel(enter 'quit' to exit):");
memset(buff, 0, BUFF_SZ);
if (fgets(buff, BUFF_SZ, stdin) == NULL)
{
perror("fgets");
break;
}buff[strlen(buff) - 1] = '\0';
if (write(fd, buff, strlen(buff)) < 0)
{
perror("write");
break;
}if (read(fd, buff, BUFF_SZ) < 0)
{
perror("read");
break;
}else
{
printf("The read string is from kernel:%s\n", buff);
}} while(strncmp(buff, "quit", 4));
close(fd);
exit(0);
}
Makefile
ifeq ($(KERNELRELEASE),) KERNELDIR ?= /lib/modules/$(shell uname -r)/build PWD := $(shell pwd) modules:$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
modules_install:
[code]$(MAKE) -C $(KERNELDIR) M=$(PWD) modules_install
clean:
rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions
.PHONY: modules modules_install clean
else
obj-m := test_drv.o
endif
[/code]
test_drv_load
#!/bin/sh
module="test_drv"
device="test_dev"
mode="664"
group="david"
# remove stale nodes
rm -f /dev/${device}# invoke insmod with all arguments we got
# and use a pathname, as newer modutils don't look in . by default
/sbin/insmod -f ./$module.ko $* || exit 1
major=`cat /proc/devices | awk "\\$2==\"$device\" {print \\$1}"`
mknod /dev/${device} c $major 0
# give appropriate group/permissions
chgrp $group /dev/${device}
chmod $mode /dev/${device}
test_drv_unload
#!/bin/sh
module="test_drv"
device="test_dev"
# invoke rmmod with all arguments we got
/sbin/rmmod $module $* || exit 1
# remove nodes
rm -f /dev/${device}exit 0
截图
遇到的问题
按照步骤运行时,Makefile文件出现了问题,后发现是格式问题。按照步骤运行时,Makefile文件出现了问题,后发现是格式问题。相关文章推荐
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