PCIe驱动开发（2）— 第一个简单驱动编写和测试
一、前言
教程参考：02_实战部分_PCIE设备测试
教程参考：03_PCIe设备驱动源码解析
二、驱动编写
新建hello_pcie.c文件
touch hello_pcie.c
然后编写内容如下所示：
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/init.h>#define HELLO_PCI_DEVICE_ID 0x11e8
#define HELLO_PCI_VENDOR_ID 0x1234
#define HELLO_PCI_REVISION_ID 0x10static struct pci_device_id ids[] = {{ PCI_DEVICE(HELLO_PCI_VENDOR_ID, HELLO_PCI_DEVICE_ID), },{ 0 , }
};static struct hello_pci_info_t {struct pci_dev *dev;void __iomem *address_bar0;
} hello_pci_info;MODULE_DEVICE_TABLE(pci, ids);static irqreturn_t hello_pci_irq_handler(int irq, void *dev_info)
{struct hello_pci_info_t *_pci_info = dev_info;uint32_t irq_status;// get irq_stutasirq_status = *((uint32_t *)(_pci_info->address_bar0 + 0x24));printk("hello_pcie: get irq status: 0x%0x\n", irq_status);// clean irq*((uint32_t *)(_pci_info->address_bar0 + 0x64)) = irq_status;// get irq_stutasirq_status = *((uint32_t *)(_pci_info->address_bar0 + 0x24));if(irq_status == 0x00){printk("hello_pcie: receive irq and clean success. \n");return IRQ_HANDLED;}else{printk("hello_pcie: receive irq but clean failed !!! \n");return IRQ_NONE;}
}static int hello_pcie_probe(struct pci_dev *dev, const struct pci_device_id *id)
{int bar = 0;int ret;resource_size_t len;ret = pci_enable_device(dev);if(ret) {return ret;}len = pci_resource_len(dev, bar);hello_pci_info.address_bar0 = pci_iomap(dev, bar, len);hello_pci_info.dev = dev;// register interruptret = request_irq(dev->irq, hello_pci_irq_handler, IRQF_SHARED, "hello_pci", &hello_pci_info);if(ret) {printk("request IRQ failed.\n");return ret;}// enable irq for finishing factorial computation*((uint32_t *)(hello_pci_info.address_bar0 + 0x20)) = 0x80;return 0;
}static void hello_pcie_remove(struct pci_dev *dev)
{// disable irq for finishing factorial computation*((uint32_t *)(hello_pci_info.address_bar0 + 0x20)) = 0x01;free_irq(dev->irq, &hello_pci_info);pci_iounmap(dev, hello_pci_info.address_bar0);pci_disable_device(dev);
}static struct pci_driver hello_pci_driver = {.name = "hello_pcie",.id_table = ids,.probe = hello_pcie_probe,.remove = hello_pcie_remove,
};static int __init hello_pci_init(void)
{return pci_register_driver(&hello_pci_driver);
}static void __exit hello_pci_exit(void)
{pci_unregister_driver(&hello_pci_driver);
}MODULE_LICENSE("GPL");
module_init(hello_pci_init);
module_exit(hello_pci_exit);三、驱动编译
新建Makefile文件编写内容如下:
ifeq ($(KERNELRELEASE),)KERNELDIR ?= /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)all:$(MAKE) -C $(KERNELDIR) M=$(PWD) modules clean:rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions Module* modules*.PHONY: all cleanelseobj-m := hello_pcie.o
endif然后执行 make命令进行编译
编译完成后可以得到驱动对应的 .ko文件
四、驱动加载及测试
驱动编译完成后使用如下命令加载即可：
sudo insmod hello_pcie.ko
然后使用lspci查看该pcie设备，可以看到驱动加载成功：
同时我们也可以看到其BAR0基地址为0xfea00000，我们使用devmem向其0x08编译地址写入数据进行阶乘运算：
使用详细说明可以查看查看qemu源码的docs/specs/edu.txt文件
然后我们使用dmesg命令可以查看驱动的相关打印：
