linux设备驱动之PCIE驱动开发

PCIE（PCI Express)是INTEL提出的新一代的总线接口,目前普及的PCIE 3.0的传输速率为8GT/s，下一代PCIE 4.0将翻番为16GT/S，因为传输速率快广泛应用于数据中心、云计算、人工智能、机器学习、视觉计算、显卡、存储和网络等领域。PCIE插槽是可以向下兼容的，比如PCIE 1X接口可以插4X、8X、16X的插槽上。

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！

源代码

#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 0x999static 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);

运行结果

程序运行后，在linux内核注册PCIE设备，内容如下

下载

PCIE驱动开发（内含Makefile，直接编译即可使用）
http://download.csdn.net/download/u010872301/10116259