一种基于虚拟端点的PCIe交换机地址分配方案

A PCIe switch address allocation scheme based on virtual endpoints

针对PCIe总线特性,结合工业控制装备的应用特性以及设计、调试和查找问题的便利性,提出一种基于虚拟端点的PCIe交换机地址分配方案。通过分析PCIe设备的枚举与资源分配过程,将虚拟端点添加到PCIe交换机系统拓扑结构中,设计PCIe外设地址空间固定分配机制,并给出外设的物理槽位号的计算公式,可在外设交互故障时刻快速定位故障外设。通过实验验证,在支持热插拔的装置中,无论外设板卡的运行数目、类型和位置如何改变,该地址分配方案可实现各下游虚拟PCI桥下接入的有效端点分配的地址空间固定,且消除了遍历查询外设地址环节,提高了数据传输的效率,有益于PCIe总线更加便捷地应用于工控领域。

A virtual endpoint-based address allocation scheme for PCIe switches is proposed for the PCIe bus characteristics,combined with the application characteristics of industrial control equipment and the convenience of design,debugging and problem finding.By analyzing the enumeration and resource allocation process of PCIe devices,adding virtual endpoints to the PCIe switch system topology,designing a fixed allocation mechanism for PCIe peripheral address space,and giving a formula for calculating the physical slot number of peripherals,the faulty peripheral can be quickly located at the moment of peripheral interaction failure.Through experimental verification,the address allocation scheme can realize the fixed address space allocated to the valid endpoints accessed under each downstream virtual PCI bridge in the device supporting hot-swapping,regardless of the number,type and location of peripheral board operation changes,and eliminates the traversal query peripheral address link to improve the efficiency of data transmission,which is beneficial to the PCIe bus can be more conveniently applied to the industrial control field.