xenomai驱动开发-参考博文-3 典型linux-PCIE驱动

转自： https://blog.csdn.net/u010872301/article/details/78519371
实现基本的PCIE驱动程序，实现以下模块：初始化设备、设备打开、数据读写和控制、中断处理、设备释放、设备卸载。本程序适合PCIE驱动开发通用调试的基本框架，对于具体PCIE设备，需要配置相关寄存器才可以使用！

点击查看代码

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/signal.h>
#include <linux/init.h>
#include <linux/cdev.h>
#include <linux/delay.h>
#include <linux/poll.h>
#include <linux/device.h>
#include <linux/pci.h>
#include <linux/interrupt.h> 
#include <asm/uaccess.h> 
 
MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("pcie device driver");
 
#define DEV_NAME "hello_pcie"
#define DEBUG 
 
#ifdef DEBUG
	#define DEBUG_ERR(format,args...) \
	do{  \
		printk("[%s:%d] ",__FUNCTION__,__LINE__); \
		printk(format,##args); \
	}while(0)
#else
	#define DEBUG_PRINT(format,args...) 
#endif
 
//1M 
#define DMA_BUFFER_SIZE 1*1024*1024 
#define FASYNC_MINOR 1
#define FASYNC_MAJOR 244
#define DEVICE_NUMBER 1
 
static struct class * hello_class;
static struct device * hello_class_dev;
 
struct hello_device
{
	struct pci_dev* pci_dev;
	struct cdev cdev;
	dev_t devno;
}my_device;
 
//barn(n=0,1,2或者0，1，2，3，4，5) 空间的物理地址，长度，虚拟地址
unsigned long bar0_phy;
unsigned long bar0_vir;
unsigned long bar0_length;
unsigned long bar1_phy;
unsigned long bar1_vir;
unsigned long bar1_length;
 
//进行DMA转换时，dma的源地址和目的地址
dma_addr_t dma_src_phy;
dma_addr_t dma_src_vir;
dma_addr_t dma_dst_phy;
dma_addr_t dma_dst_vir;
 
//根据设备的id填写,这里假设厂商id和设备id
#define HELLO_VENDOR_ID 0x666
#define HELLO_DEVICE_ID 0x999
static struct pci_device_id hello_ids[] = {
    {HELLO_VENDOR_ID,HELLO_DEVICE_ID,PCI_ANY_ID,PCI_ANY_ID,0,0,0},
    {0,}
};
MODULE_DEVICE_TABLE(pci,hello_ids);
 
static int hello_probe(struct pci_dev *pdev, const struct pci_device_id *id);
static void hello_remove(struct pci_dev *pdev);
static irqreturn_t hello_interrupt(int irq, void * dev);
 
//往iATU写数据的函数
void iATU_write_config_dword(struct pci_dev *pdev,int offset,int value)
{
	
}
 
//假设需要将bar0映射到内存
static void iATU_bar0(void)
{
	//下面几步，在手册中有example
	//iATU_write_config_dword(my_device.pci_dev,iATU Lower Target Address ,xxx);//xxx表示内存中的地址，将bar0映射到这块内存
	//iATU_write_config_dword(my_device.pci_dev,iATU Upper Target Address ,xxx);//xxx表示内存中的地址，将bar0映射到这块内存
 
	//iATU_write_config_dword(my_device.pci_dev,iATU Control 1,0x0);//映射的时内存，所以写0x0
	//iATU_write_config_dword(my_device.pci_dev,iATU Control 2,xxx);//使能某个region，开始地址转换
}
 
 
//往dma配置寄存器中读写数据的函数，这是难点一：dma寄存器的寻址。
int dma_read_config_dword(struct pci_dev *pdev,int offset)
{
	int value =0;
	return value;
}
 
void dma_write_config_dword(struct pci_dev *pdev,int offset,int value)
{
	
}
 
void dma_init(void)
{
	int pos;
	u16 msi_control;
	u32 msi_addr_l;
	u32 msi_addr_h;
	u32 msi_data;
	
	//1.dma 通道0 写初始化 。如何访问DMA global register 寄存器组需要根据具体的硬件，可以通过pci_write/read_config_word/dword，
	//也可以通过某个bar，比如通过bar0+偏移量访问。
	//1.1 DMA write engine enable =0x1，这里请根据自己的芯片填写
	//dma_write_config_dword(->pci_dev,DMA write engine enable,0x1);	
	//1.2 获取msi能力寄存器的地址
	pos =pci_find_capability(my_device.pci_dev,PCI_CAP_ID_MSI);
	//1.3 读取msi的协议部分，得到pci设备是32位还是64位，不同的架构msi data寄存器地址同
	pci_read_config_word(my_device.pci_dev,pos+2,&msi_control);
	//1.4 读取msi能力寄存器组中的地址寄存器的值
	pci_read_config_dword(my_device.pci_dev,pos+4,&msi_addr_l);	
	//1.5 设置 DMA write done IMWr Address Low.这里请根据自己的芯片填写
	//dma_write_config_dword(my_device.pci_dev,DMA write done IMWr Address Low,msi_addr_l);
	//1.6 设置 DMA write abort IMWr Address Low.这里请根据自己的芯片填写
	//dma_write_config_dword(my_device.pci_dev,DMA write abort IMWr Address Low,msi_addr_l);
	
	if(msi_control&0x80){
		//64位的
		//1.7 读取msi能力寄存器组中的高32位地址寄存器的值
		pci_read_config_dword(my_device.pci_dev,pos+0x8,&msi_addr_h);
		//1.8 读取msi能力寄存器组中的数据寄存器的值
		pci_read_config_dword(my_device.pci_dev,pos+0xc,&msi_data);
		
		//1.9 设置 DMA write done IMWr Address High.这里请根据自己的芯片填写
		//dma_write_config_dword(my_device.pci_dev,DMA write done IMWr Address High,msi_addr_h);
		//1.10 设置 DMA write abort IMWr Address High.这里请根据自己的芯片填写
		//dma_write_config_dword(my_device.pci_dev,DMA write abort IMWr Address High,msi_addr_h);
		
	} else {
		//1.11 读取msi能力寄存器组中的数据寄存器的值
		pci_read_config_dword(my_device.pci_dev,pos+0x8,&msi_data);
	}
	
	//1.12 把数据寄存器的值写入到dma的控制寄存器组中的 DMA write channel 0 IMWr data中
	//dma_write_config_dword(my_device.pci_dev,DMA write channel 0 IMWr data,msi_data);
	
	//1.13 DMA channel 0 control register 1 = 0x4000010
	//dma_write_config_dword(my_device.pci_dev,DMA channel 0 control register 1,0x4000010);
	
	//2.dma 通道0 读初始化 和上述操作类似，不再叙述。
}
 
static int hello_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
	int i;
	int result;
	//使能pci设备
	if (pci_enable_device(pdev)){
        result = -EIO;
		goto end;
	}
	
	pci_set_master(pdev);	
	my_device.pci_dev=pdev;
 
	if(unlikely(pci_request_regions(pdev,DEV_NAME))){
		DEBUG_ERR("failed:pci_request_regions\n");
		result = -EIO;
		goto enable_device_err;
	}
	
	//获得bar0的物理地址和虚拟地址
	bar0_phy = pci_resource_start(pdev,0);
	if(bar0_phy<0){
		DEBUG_ERR("failed:pci_resource_start\n");
		result =-EIO;
		goto request_regions_err;
	}
	
	//假设bar0是作为内存，流程是这样的，但是在本程序中不对bar0进行任何操作。
	bar0_length = pci_resource_len(pdev,0);
	if(bar0_length!=0){
		bar0_vir = (unsigned long)ioremap(bar0_phy,bar0_length);
	}
	
	//申请一块DMA内存，作为源地址，在进行DMA读写的时候会用到。
	dma_src_vir=(dma_addr_t)pci_alloc_consistent(pdev,DMA_BUFFER_SIZE,&dma_src_phy);
	if(dma_src_vir != 0){
		for(i=0;i<DMA_BUFFER_SIZE/PAGE_SIZE;i++){
			SetPageReserved(virt_to_page(dma_src_phy+i*PAGE_SIZE));
		}
	} else {
		goto free_bar0;
	}
	
	//申请一块DMA内存，作为目的地址，在进行DMA读写的时候会用到。
	dma_dst_vir=(dma_addr_t)pci_alloc_consistent(pdev,DMA_BUFFER_SIZE,&dma_dst_phy);
	if(dma_dst_vir!=0){
		for(i=0;i<DMA_BUFFER_SIZE/PAGE_SIZE;i++){
			SetPageReserved(virt_to_page(dma_dst_phy+i*PAGE_SIZE));
		}
	} else {
		goto alloc_dma_src_err;
	}
	//使能msi，然后才能得到pdev->irq
	 result = pci_enable_msi(pdev);
	 if (unlikely(result)){
		DEBUG_ERR("failed:pci_enable_msi\n");
		goto alloc_dma_dst_err;
    }
	
	result = request_irq(pdev->irq, hello_interrupt, 0, DEV_NAME, my_device.pci_dev);
    if (unlikely(result)){
       DEBUG_ERR("failed:request_irq\n");
	   goto enable_msi_error;
    }
	
	//DMA 的读写初始化
	dma_init();
	
enable_msi_error:
		pci_disable_msi(pdev);
alloc_dma_dst_err:
	for(i=0;i<DMA_BUFFER_SIZE/PAGE_SIZE;i++){
		ClearPageReserved(virt_to_page(dma_dst_phy+i*PAGE_SIZE));
	}
	pci_free_consistent(pdev,DMA_BUFFER_SIZE,(void *)dma_dst_vir,dma_dst_phy);
alloc_dma_src_err:
	for(i=0;i<DMA_BUFFER_SIZE/PAGE_SIZE;i++){
		ClearPageReserved(virt_to_page(dma_src_phy+i*PAGE_SIZE));
	}
	pci_free_consistent(pdev,DMA_BUFFER_SIZE,(void *)dma_src_vir,dma_src_phy);
free_bar0:
	iounmap((void *)bar0_vir);
request_regions_err:
	pci_release_regions(pdev);
	
enable_device_err:
	pci_disable_device(pdev);
end:
	return result;
}
 
static void hello_remove(struct pci_dev *pdev)
{
	int i;
	
	free_irq(pdev->irq,my_device.pci_dev);
	pci_disable_msi(pdev);
 
	for(i=0;i<DMA_BUFFER_SIZE/PAGE_SIZE;i++){
		ClearPageReserved(virt_to_page(dma_dst_phy+i*PAGE_SIZE));
	}
	pci_free_consistent(pdev,DMA_BUFFER_SIZE,(void *)dma_dst_vir,dma_dst_phy);
 
	for(i=0;i<DMA_BUFFER_SIZE/PAGE_SIZE;i++){
		ClearPageReserved(virt_to_page(dma_src_phy+i*PAGE_SIZE));
	}
	pci_free_consistent(pdev,DMA_BUFFER_SIZE,(void *)dma_src_vir,dma_src_phy);
 
	iounmap((void *)bar0_vir);
	pci_release_regions(pdev);
	pci_disable_device(pdev);
}
 
//难点三：中断响应设置
static irqreturn_t hello_interrupt(int irq, void * dev)
{  
    //1.该中断调用时机：当DMA完成的时候，会往msi_addr中写入msi_data,从而产生中断调用这个函数
	//2.根据DMA Channel control 1 register寄存器的状态，判断读写状态，读失败，写失败，读成功，写成功，做出不同的处理。
	return 0;
}
static struct pci_driver hello_driver = {
    .name = DEV_NAME,
    .id_table = hello_ids,
    .probe = hello_probe,
    .remove = hello_remove,
};
 
static int hello_open(struct inode *inode, struct file *file)
{
	printk("driver: hello_open\n");
	//填写产品的逻辑
	return 0;
}
 
int hello_close(struct inode *inode, struct file *file)
{
	printk("driver: hello_close\n");
	//填写产品的逻辑
	return 0;
}
 
long hello_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	//填写产品的逻辑
	//为应用层提供的函数接口，通过解析cmd，在switch中做出不同的处理。 
	iATU_bar0();//某个合适的地方调用
	return 0;
	
}
 
//难点二：启动dma的读写（read和write函数).
static struct file_operations hello_fops = {
	.owner   		=  THIS_MODULE,    
	.open   		=  hello_open,     
	.release 		=  hello_close,
	.unlocked_ioctl =  hello_unlocked_ioctl,
};
 
static int hello_drv_init(void)
{
	int ret;
	ret = pci_register_driver(&hello_driver);
	if (ret < 0) {
		printk("failed: pci_register_driver\n");
		return ret;
	}
	
	ret=alloc_chrdev_region(&my_device.devno,0,DEVICE_NUMBER,"hello");
	if (ret < 0) {
		printk("failed: register_chrdev_region\n");
		return ret;
	}
 
	cdev_init(&my_device.cdev, &hello_fops);
	ret = cdev_add(&my_device.cdev, my_device.devno, DEVICE_NUMBER);
	if (ret < 0) {
		printk("faield: cdev_add\n");
		return ret;
	}
	
	hello_class = class_create(THIS_MODULE, "hello_class");
	hello_class_dev = device_create(hello_class, NULL, my_device.devno, NULL, "hello_device"); 
 
	return 0;
}
 
static void hello_drv_exit(void)
{
	device_destroy(hello_class,my_device.devno);
	class_destroy(hello_class);
		
	cdev_del(&(my_device.cdev));
	unregister_chrdev_region(my_device.devno,DEVICE_NUMBER);
	pci_unregister_driver(&hello_driver);
}
 
module_init(hello_drv_init);
module_exit(hello_drv_exit);