PCIe驱动开发（2）— 第一个简单驱动编写和测试

news2024/9/20 0:59:50

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	0x10

static 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_stutas
	irq_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_stutas
	irq_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 interrupt
	ret = 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 clean

else
  obj-m := hello_pcie.o
endif