[feat] add linux hello_driver

linux/driver/hello_driver/Makefile

@@ -0,0 +1,14 @@
+KERNELDIR := /lib/modules/$(shell uname -r)/build
+CURRENT_PATH := $(shell pwd)
+obj-m := hello_driver.o
+
+build: kernel_modules
+
+kernel_modules:
+	$(MAKE) -C $(KERNELDIR) M=$(CURRENT_PATH) modules
+	$(CROSS_COMPILE)gcc -o app.elf app.c
+clean:
+	$(MAKE) -C $(KERNELDIR) M=$(CURRENT_PATH) clean
+	rm -rf app.elf
+
+

linux/driver/hello_driver/app.c

@@ -0,0 +1,36 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+
+uint8_t buffer[512] = { 0 };
+
+int main(int argc, char *argv[])
+{
+	int fd;
+	int ret;
+
+	fd = open(argv[1], O_RDWR);
+	if (fd < 0) {
+		printf("open failed!\r\n");
+		return -1;
+	}
+	if (!strcmp("read", argv[2])) {
+		printf("read data from kernel\r\n");
+		ret = read(fd, buffer, sizeof(buffer));
+		printf("ret len:%d data:%s\r\n", ret, buffer);
+	} else if (!strcmp("write", argv[2])) {
+		printf("write data to kernel %s len:%ld\r\n", argv[3], strlen(argv[3]));
+		ret = write(fd, argv[3], strlen(argv[3]));
+		printf("ret len:%d\r\n", ret);
+	} else {
+		printf("please input correct para, read/write\r\n");
+	}
+	close(fd);
+	return 0;
+}
+

linux/driver/hello_driver/hello_driver.c

@@ -0,0 +1,89 @@
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/cdev.h>
+
+dev_t hello_dev_id;
+struct cdev hello_cdev;
+int hello_major = 0;
+int hello_minor;
+
+uint8_t kernel_buffer[1024] = { 0 };
+static struct class *hello_driver_class;
+
+static int hello_driver_open(struct inode *inode, struct file *file)
+{
+	printk("hello_driver_open\r\n");
+	return 0;
+}
+
+static int hello_driver_release(struct inode *inode, struct file *file)
+{
+	printk("hello_driver_release\r\n");
+	return 0;
+}
+
+static ssize_t hello_driver_read(struct file *file, char __user *buffer, size_t size, loff_t *ppos)
+{
+	printk("hello_driver_read size=%ld\r\n", size);
+	copy_to_user(buffer, kernel_buffer, size);
+	return size;
+}
+
+static ssize_t hello_driver_write(struct file *file, const char __user *buffer, size_t size, loff_t *ppos)
+{
+	printk("hello_driver_write size=%ld\r\n", size);
+	copy_from_user(kernel_buffer, buffer, size);
+	return size;
+}
+
+static const struct file_operations hello_driver_fops = {
+	.owner   = THIS_MODULE,
+	.open    = hello_driver_open,
+	.release = hello_driver_release,
+	.read    = hello_driver_read,
+	.write   = hello_driver_write,
+};
+
+static int __init hello_driver_init(void)
+{
+	printk("hello_driver_init\r\n");
+
+	/* automatically apply for device number */
+	alloc_chrdev_region(&hello_dev_id, 0, 1, "hello_driver");
+	hello_major = MAJOR(hello_dev_id);
+	hello_minor = MINOR(hello_dev_id);
+	printk("hello_driver: major=%d, minor=%d\r\n", hello_major, hello_minor);
+
+	hello_cdev.owner = THIS_MODULE;
+	cdev_init(&hello_cdev, &hello_driver_fops);
+	cdev_add(&hello_cdev, hello_dev_id, 1);
+	// ret = register_chrdev(CHRDEVBASE_MAJOR, "hello_driver", &hello_driver_fops);
+
+	/* automatically add device node file */
+	hello_driver_class = class_create("hello_driver_class");
+	device_create(hello_driver_class, NULL, hello_dev_id, NULL, "hello_driver_device");
+
+	return 0;
+}
+
+static void __exit hello_driver_exit(void)
+{
+	printk("hello_driver_exit\r\n");
+
+	cdev_del(&hello_cdev);
+	unregister_chrdev_region(hello_dev_id, 1);
+
+	device_destroy(hello_driver_class, hello_dev_id);
+	class_destroy(hello_driver_class);
+	// unregister_chrdev(CHRDEVBASE_MAJOR, "hello_driver");
+}
+
+module_init(hello_driver_init);
+module_exit(hello_driver_exit);
+MODULE_LICENSE("GPL");