201820191201653032016531620165335实验四外设驱动程序设计

实验四外设驱动程序设计-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&＃xff08;可以多张&＃xff09;
  

实验四外设驱动程序设计-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&＃xff0c;加载模块&＃xff0c;卸载模块&＃xff0c;测试运行的截图&＃xff08;要多张&＃xff0c;全屏&＃xff0c;体现学号信息&＃xff09;
  Makefile

ifeq ($(KERNELRELEASE),)
KERNELDIR ?&＃61; /lib/modules/3.2.0-24-generic/build
PWD :&＃61; $(shell pwd)
modules:$(MAKE) -C $(KERNELDIR) M&＃61;$(PWD) modules
modules_install:$(MAKE) -C $(KERNELDIR) M&＃61;$(PWD) modules_install
clean:rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions
.PHONY: modules modules_install clean
elseobj-m :&＃61; test_drv.o
endif

test.c

/* test.c */#include #include #include #include #include #include #include #define TEST_DEVICE_FILENAME "/dev/test_dev"#define BUFF_SZ 1024int main(){int fd, nwrite, nread;char buff[BUFF_SZ];fd &＃61; open(TEST_DEVICE_FILENAME, O_RDWR);if (fd <0){perror("open");exit(1);}do{printf("Input some words to kernel(enter &＃39;quit&＃39; to exit):");memset(buff, 0, BUFF_SZ);if (fgets(buff, BUFF_SZ, stdin) &＃61;&＃61; NULL){perror("fgets");break;}buff[strlen(buff) - 1] &＃61; &＃39;\0&＃39;;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);}

test_drv.c

/* test_drv.c */#include #include #include #include #include #include #include #include #include #define TEST_DEVICE_NAME "test_dev"#define BUFF_SZ 1024static struct cdev test_dev;unsigned int major &＃61;0;static char *data &＃61; NULL;/*º¯ÊýÉùÃ÷*/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 &＃61; strlen(data);count &＃61; (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 &＃61; (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 &＃61; (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 &＃61; NULL;}return 0;}static void test_setup_cdev(struct cdev *dev, int minor,struct file_operations *fops){int err, devno &＃61; MKDEV(major, minor);cdev_init(dev, fops);dev->owner &＃61; THIS_MODULE;dev->ops &＃61; fops;err &＃61; cdev_add (dev, devno, 1);if (err){printk (KERN_NOTICE "Error %d adding test %d", err, minor);}}static struct file_operations test_fops &＃61; {.owner &＃61; THIS_MODULE,.read &＃61; test_read,.write &＃61; test_write,.open &＃61; test_open,.release &＃61; test_release,};int init_module(void){int result;dev_t dev &＃61; MKDEV(major, 0);if (major){result &＃61; register_chrdev_region(dev, 1, TEST_DEVICE_NAME);}else {result &＃61; alloc_chrdev_region(&dev, 0, 1, TEST_DEVICE_NAME);major &＃61; 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_drv_load

#!/bin/sh
module&＃61;"test_drv"
device&＃61;"test_dev"
mode&＃61;"664"
group&＃61;"linux"# remove stale nodes
rm -f /dev/${device} # invoke insmod with all arguments we got
# and use a pathname, as newer modutils don&＃39;t look in . by default
/sbin/insmod -f ./$module.ko $* || exit 1major&＃61;&＃96;cat /proc/devices | awk "\\$2&＃61;&＃61;\"$device\" {print \\$1}"&＃96;mknod /dev/${device} c $major 0# give appropriate group/permissions
chgrp $group /dev/${device}
chmod $mode /dev/${device}

test_drv_unload

#!/bin/sh
module&＃61;"test_drv"
device&＃61;"test_dev"# invoke rmmod with all arguments we got
/sbin/rmmod $module $* || exit 1# remove nodes
rm -f /dev/${device}exit 0

• 遇到的问题
  首先要注意Makefile文件中的空格和tab 的区别
  其次要在test_drv_load中把组改成虚拟机用户所在的组&＃xff0c;老师给的虚拟机所在的组就是linux,不能用原来的David&＃xff0c;否则会出现无效的组
  再有Makefile中要改成这个KERNELDIR ?&＃61; /lib/modules/3.2.0-24-generic/build