差别

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--- fpga:petalinux [2023/02/09 10:20] – [9. zynq设备上运行指定驱动的app程序] zhangguo
+++ fpga:petalinux [2023/03/17 10:12] (当前版本) – 外部编辑 127.0.0.1
@@ 行 235: / 行 235: @@
 ===== - linux 加载module =====
-<code>
+<code bash>
-insmode blink.ko
+insmod blink.ko
 # 如果有同名文件module已经加载，可以先lsmode查看
-lsmode
+lsmod   # 列出已经加载的module
-rmmode blink.ko  # 删除已加载的module, 可以在后面两次加载新的module.
+rmmod blink.ko  # 删除已加载的module, 可以在后面两次加载新的module.
+</code>
+===== - module驱动代码实例 =====
+==== - 一个简单的device module 驱动代码 ====
+主要描述用户数据和内核数据之间如何互通，因为不能直接访问，需要通过copy_to_user & copy_from_user函数来完成。
+<code c>
+#include <linux/uaccess.h>  // copy_to_user copy_from_user
+#include <asm/uaccess.h> /* for get_user and put_user */  // raw_copy_to_user, raw_copy_from_user
+/*
+* This function is called whenever a process which has already opened the
+* device file attempts to read from it.
+*/
+static ssize_t device_read(	struct file *file, /* see include/linux/fs.h */
+							char __user * buffer, /* buffer to be filled with data */
+							size_t length, /* length of the buffer */
+							loff_t * offset)
+{
+    int ret;
+    char k_buffer[20] = {0}; // kernel core buffer
+    memcpy(k_buffer, "core_to_user_msg02", length);
+    ret = copy_to_user(buffer, k_buffer, length);
+	return SUCCESS;
+}
+/*
+* This function is called when somebody tries to
+* write into our device file.
+*/
+static ssize_t device_write(struct file *file,
+							const char __user * buffer,
+							size_t length,
+							loff_t * offset)
+{
+    // user function
+    int ret;
+    char k_buffer[20] = {0}; // kernel core buffer
+    ret = copy_from_user(k_buffer, buffer, length);
+	  printk("kernel:::  blink write: %s\n", k_buffer);
+    // end
+	return SUCCESS;
+}
+</code>
+==== - gpio驱动led举例 ====
+驱动部分：
+<code c>
+#include <linux/init.h>     //定义了module_init
+#include <linux/module.h>   //最基本的头文件，其中定义了MODULE_LICENSE这一类宏
+#include <linux/fs.h>       //file_operations结构体定义在该头文件中
+#include <linux/device.h>	//class、device结构体的定义位置
+#include <linux/kernel.h>	//printk头文件
+#include <linux/uaccess.h>	//copy_from_user头文件
+#include <asm/io.h>			//ioremap头文件
+#include <linux/ioport.h>
+#include <linux/of.h>
+#include <linux/delay.h>
+//定义主设备号
+static int major_num;
+//  定义设备文件名
+#define DEVICE_NAME "leds"
+//定义class、device结构体
+#define CLASS_NAME "mygpio"
+static struct class* gpio_class;
+static struct device* gpio_device;
+#define LEDS_BASE_ADDR		(0x41200000)	//GPIO的Base addr，用于映射
+static unsigned *leds;
+static int leds_drv_open(struct inode *Inode, struct file *File)
+{
+	*leds = 0x0;
+	return 0;
+}
+static ssize_t leds_drv_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+	return 0;
+}
+static ssize_t leds_drv_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
+{
+	unsigned int ret = 0;
+	unsigned int tmp_val;
+	ret = copy_from_user(&tmp_val, buf, count);
+	*leds = tmp_val & 0xf;
+	return ret;
+}
+//  描述与设备文件触发的事件对应的回调函数指针
+static struct file_operations dev_fops =
+{
+	.owner = THIS_MODULE,
+	.open = leds_drv_open,
+	.read = leds_drv_read,
+	.write = leds_drv_write,
+};
+//  初始化Linux驱动
+static int __init leds_drv_init(void)
+{
+	int ret;
+	leds = ioremap(LEDS_BASE_ADDR, 0x100);
+	//获取主设备号
+	major_num = register_chrdev(0,DEVICE_NAME, &dev_fops);
+	//创建设备类
+	gpio_class = class_create(THIS_MODULE, CLASS_NAME);
+	if(IS_ERR(gpio_class))
+	{
+    	unregister_chrdev(major_num, DEVICE_NAME);
+    	printk(KERN_ALERT "Failed to register device class\n");
+    	return PTR_ERR(gpio_class);
+    }
+    //注册设备
+	gpio_device = device_create(gpio_class, NULL, MKDEV(major_num, 0), NULL, DEVICE_NAME);
+	if(IS_ERR(gpio_device))
+	{
+    	class_destroy(gpio_class);
+    	unregister_chrdev(major_num, DEVICE_NAME);
+    	printk(KERN_ALERT "Failed to create the device\n");
+    	return PTR_ERR(gpio_device);
+    }
+    printk(KERN_INFO "LED_GPIO_init: device created correctly\n");
+	return 0;
+}
+// 卸载Linux驱动
+static void __exit leds_drv_exit(void)
+{
+	iounmap(leds);
+	//  删除设备文件,后创建的先卸载
+	device_destroy(gpio_class, MKDEV(major_num, 0));
+	class_destroy(gpio_class);
+	unregister_chrdev(major_num,DEVICE_NAME);	//释放设备号
+	//  输出日志信息
+	printk("LED_GPIO_exit success!\n");
+}
+//  注册初始化Linux驱动的函数
+module_init(leds_drv_init);
+//  注册卸载Linux驱动的函数
+module_exit(leds_drv_exit);
+MODULE_LICENSE("GPL");
+</code>
+应用程序app部分：
+<code c>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+int main(int argc, char** argv)
+{
+        int fd;
+        fd = open("/dev/leds", O_RDWR);
+        if(fd < 0)
+        {
+                printf("fd = %d open fialed!\n", fd);
+        }
+        unsigned int leds = 0;
+        while(1)
+        {
+        	write(fd, &leds, 4);
+        	leds++;
+        	leds %= 0xf;
+                sleep(1);
+        }
+        close(fd);
+        return 0;
+}
 </code>