基于SXP36x6G的SAS Expander固件设计-计算机技术专业论文.docxVIP

ABSTRACT SAS Expander is a kind of device that is used to expand the connectivity of SAS controller.The target device of this design is just a kind of SAS Expander chip produced by the company PMC. Previously,according to the customers need,our company was responsible for designing a kind of server that has disk array. The capacity of disk enclosure is up to 12 hard disk drives, and the data transfer rate should be ensured. So,SAS Expander should be used as the switch device. The static modle of this firmware design is composed of the following modules: Bootloader module, real-time operating system module, device driver module, SCSI target emulator module, SAS port module, SMP module, STP module, enclosure management module, hard disk validation module, etc. The designs dynamic modle contains several threads, they are: SCSI initiator thread, SAS port thread, SMP initiator thread, Port management thread, watch dog thread, etc. All these threads run independantly with fixed priority, and communicate with each other by the message queue mechanism. During the system initialization stage, the bootloader initializes hardware devices and prepares the execution environment for upper layer programs. Inorder to check the correctness of the partitions within the ROM, the CRC algorithm is introduced to generate checksum value for the length of each partition. For the sake of improving the reliability of firmware update operation, the mechanism of switching between active/inactive partitions is used, which ensures the system can always boot no matter whether update is successful. Through the development process, the performance of firmware fully reaches the design requirements, and shows good compatibility to various storage devices. Key Words: SAS, Expander, Firmware 目录 第一章 绪论 1 1.1 项目背景 1 1.2 技术背景 1  HYPERLINK \l _TOC_250001 并行 SCSI 技术 1  HYPERLINK \l _TOC_250000 串行 SCSI 技术 2 SAS 协议介绍 3 SAS Expander 4 第二章 开发平台 8 2.1 器件描述 8 2.2 开发与调试环境 10 第三章 固件架构设计