NAND Flash算法验证平台研制

发布时间：2018-01-28 09:04

本文关键词： NAND Flash AXI DMA Zynq FTL 千兆以太网　出处：《哈尔滨工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：NAND Flash存储器因具有速度快、体积小、存储容量大、抗振动性能强等优点得到了大范围应用。但由于NAND Flash具有不能连续寻址、先擦后写和存在坏块等缺陷，使得已有的磁盘管理方法不再适用于NAND Flash存储器，广大研究者一直致力于寻求能快速解决NAND Flash存储问题的方法。目前NAND Flash管理算法评估还没有统一的验证平台，亟需设计一款简单通用的平台对管理算法进行直观评估。本文深入分析NAND Flash操作特性和管理算法的研究方向后，基于Xilinx公司全可编程的Zynq-7000Soc研制了一款软、硬件结合的NAND Flash管理算法验证平台。在硬件方面，利用Zynq内嵌的PL（Programmable Logic，，PL）实现了NAND Flash控制器、数据传输主控模块，数据错误引入模块和坏块管理模块等。其中，NAND Flash控制器采用双乒乓缓存以提升数据写入速度；数据传输主控模块一方面采用AXI GP接口实现了PS（Processing System，PS）应用程序对其的控制功能，另一方面采用AXI HP接口实现了AXI DMA以完成PS和PL间的高速数据传输；数据错误引入模块通过AXI GP接口获取PS给出的错误位置，并能在NAND Flash页编程时实现相应的位翻转功能；坏块管理模块除实现正常读、写、擦除失败产生的坏块标记和重映射外，还利用Xilinx的HLS工具实现了BCH纠错算法来发现数据出错的坏块并标记与重映射。在PS设计方面，通过移植实时系统FreeRTOS对应用程序进行管理，并利用Zynq内嵌的USB控制器实现了USB大容量存储协议以将多种文件系统引入验证平台，同时通过移植LwIP TCP/IP协议栈实现了千兆以太网的传输，完成算法性能分析时必要数据的快速上传。最后，本文利用PS实现了经典的页映射算法、FAST等FTL算法以作为其它FTL算法的参考基准，并可为验证数据压缩等高级算法提供运行环境。此外，为弥补商业软件的不足，设计了测试软件对NAND Flash管理算法的常用指标进行评估。系统测试表明，研制的NAND Flash算法验证平台能够实现对NANDFlash管理算法的有效验证，并可给出直观的评估结果，满足设计要求。
[Abstract]:NAND Flash memory has been widely used because of its advantages of high speed, small volume, large storage capacity and strong anti-vibration performance. However, NAND Flash can not be continuously addressed. The existing disk management methods are no longer suitable for NAND Flash memory due to the defects such as erasing and writing after writing and the existence of bad blocks. Many researchers have been trying to find a way to solve the NAND Flash storage problem quickly. At present, there is no unified verification platform for the evaluation of NAND Flash management algorithm. It is urgent to design a simple and universal platform to evaluate the management algorithm directly. This paper deeply analyzes the operating characteristics of NAND Flash and the research direction of management algorithm. Based on Zynq-7000Soc of Xilinx Company, a software and hardware NAND Flash management algorithm verification platform is developed. In the aspect of hardware, the NAND Flash controller and the main control module of data transmission are realized by using the PL(Programmable logic device embedded in Zynq. The data error introduction module and the bad block management module, etc., in which the nand Flash controller adopts double ping-pong buffer to improve the data writing speed; On the one hand, the main control module of data transmission uses AXI GP interface to realize the control function of PS(Processing system PS-based application program. On the other hand, AXI DMA is implemented by AXI HP interface to complete the high-speed data transmission between PS and PL. The data error introduction module obtains the error position given by PS through the AXI GP interface, and can realize the corresponding bit flipping function when programming on the NAND Flash page. The bad block management module implements normal reading, writing, and erasing bad block tags and remapping due to failure. The BCH error correction algorithm is implemented by using Xilinx's HLS tool to detect bad blocks of data errors and to mark and remap. In the aspect of PS design, the application program is managed by transplanting the real-time system FreeRTOS. And the USB controller embedded in Zynq is used to implement the USB mass storage protocol to introduce a variety of file systems into the verification platform. At the same time, the transmission of Gigabit Ethernet is realized by transplanting the LwIP TCP/IP protocol stack, and the necessary data is uploaded quickly when the algorithm performance analysis is completed. Finally. In this paper, we use PS to implement the classical FTL algorithm, such as fast, which can be used as a reference reference for other FTL algorithms, and provide a running environment for the verification of advanced algorithms such as data compression. In order to make up for the shortage of commercial software, the test software is designed to evaluate the common indexes of NAND Flash management algorithm. The system test shows that the developed NAND. The Flash algorithm verification platform can effectively verify the NANDFlash management algorithm, and can give the intuitive evaluation results to meet the design requirements.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP333

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