Embedded Linux System Transplantation And Driver Design Based On Loongson 2K1000 Processor

Embedded processors are the core components of embedded systems and mainly rely on imported foreign chips.Therefore,it is imperative to promote the use of domestic chips.The domestic Loongson processor has completely independent intellectual property rights,and has launched independent research and development instruction sets,which are used in key areas such as Beidou.This topic uses the Loongson 2K1000 processor to make a complete embedded software system that can work normally,and design device drivers,which is of great significance for the subsequent construction of a complete bus test system with external test equipment based on this.The requirement of this subject is to build an embedded software system that can work normally,based on this to realize the network communication and file transfer functions,as well as the configuration and access to the external PCIE equipment.Therefore,according to the characteristics of the processor and the composition of the embedded system,the method of compiling and transplanting each part of the embedded software system is proposed.According to the development method of the Linux device driver and the characteristics of the device,the design scheme of the network device driver and the PCIE device driver is proposed.The boot program,embedded Linux kernel and root file system constitute the most basic embedded software system.Based on the architecture of Loongson2K1000,this paper chooses PMON as the boot program,studies the PMON startup process and compilation and transplantation methods,tailors and compiles a streamlined Linux kernel according to the actual needs of the subject,modifies the root file system configuration according to the processor parameters,and uses the Buildroot tool to make the root File system.In the process of network device driver development,first study the hardware structure of the Loongson 2K1000 network system,analyze the Linux system network protocol level and the key data structure of the network device driver development,modify the network controller parameters in the device tree according to the processor parameters,and design the control Network devices and network device drivers that implement network communication functions.In the process of PCIE device driver development,first study the PCIE bus protocol and the characteristics of the device itself.According to the Linux character device driver framework,use related data structures and underlying functions to design a device driver that can configure PCIE devices and read and write IO.Finally,this article tests the transplanted software system and the developed device driver.Test whether PMON's own function and parameter modification in the source code take effect,and whether PMON can successfully boot the Linux kernel.Test the functions of each subsystem of the embedded Linux kernel.Test the loading and network connection functions of the network device driver,use the two-way file transfer between the board and the virtual machine to test the network transmission function,and use the iperf tool to test the network performance through TCP and UDP transmission.Write a test program to call the PCIE device driver to test the configuration space and IO space of the PCIE device for reading and writing functions.The test results show that the expected functions of the software system and device drivers can be implemented normally and meet the design requirements.