2018-2019-1 20165211 實驗四 外設驅動程序設計

任務一

1.實驗要求

學習資源中全課中的“hqyj.嵌入式Linux應用程序開發標準教程.pdf”中的第十一章 提交康奈爾筆記的照片（可以多張）

2. 任務完成

任務二

1. 實驗要求

在Ubuntu完成資源中全課中的“hqyj.嵌入式Linux應用程序開發標準教程.pdf”中的第十一章的test試驗 提交編譯，加載模塊，卸載模塊，測試運行的截圖（要多張，全屏，體現學號信息）

2. 實驗代碼

test_drv.c

/* 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) {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"); }

test.c

/* test.c */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/stat.h> #include <sys/types.h> #include <unistd.h> #include <fcntl.h> #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:$(MAKE) -C $(KERNELDIR) M=$(PWD) modules_install clean:rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions .PHONY: modules modules_install clean elseobj-m := test_drv.o endif

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_load

#!/bin/sh module="test_drv" device="test_dev"# invoke rmmod with all arguments we got sudo /sbin/rmmod $module $* || exit 1# remove nodes rm -f /dev/${device}exit 0

3. 實驗步驟

• 在虛擬設備驅動源碼目錄下編譯并加載驅動模塊

  $ make clean;make $ ./test_drv_load

• 編譯并運行測試程序

  $ gcc –o test test.c $ ./test

• 卸載驅動程序

  $ ./test_drv_unload

• 通過dmesg命令查看內核打印的消息

  $ dmesg|tail –n 10 …… The major of the test device is 250 This is open operation This is release operation Test device uninstalled

4. 實驗截圖

轉載于:https://www.cnblogs.com/akashi/p/10056082.html

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