在嵌入式Linux开发过程中，经常会使用到nor flash，nand flash等存储设备，由于flash的芯片型号和接口类型较多，性能不一，我们需要对系统中使用的flash性能进行分析，并对设备工作的稳定性进行测试。
flash设备在嵌入式系统中，会被驱动为MTD分区，在linux kernel中，提供了针对MTD的测试模块，方面开发人员对flash的功能，性能，稳定性等进行测试。
使用make ARCH=arm menuconfig打开kernel配置界面，配置 "Device Drivers" -> "Memory Technology Device (MTD) support" -> "MTD tests support"，该选项只可以配置为按模块编译，保存配置后退出。
使用make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- modules编译代码，生成测试工具模块，存储在目录drivers/mtd/tests中，包括以下内容：
mtd_nandecctest.ko：nand flash的ECC校验测试
mtd_pagetest.ko：nand flash的page读写测试
mtd_speedtest.ko：MTD分区的读写速度测试
mtd_subpagetest.ko：nand flash的sub-page接口测试
mtd_oobtest.ko：nand falsh的OOB区域读写测试
mtd_readtest.ko：读取整个MTD分区
mtd_stresstest.ko：随机读写，擦除操作测试
mtd_torturetest.ko：该功能可用于做稳定性或者寿命测试，随机操作直到发生错误
在实时ko文件进行测试时，可以通过dev=n指定要测试的MTD分区，示例如下：
insmod mtd_stresstest.ko dev=9 count=1000
[ 3289.273771] ========================================
[ 3289.279826] mtd_stresstest: MTD device: 9
[ 3289.284079] mtd_stresstest: MTD device size 268435456, eraseblock size 131072, page size 2048, count of eraseblocks 2048, pages per eraseblock 64, OOB size 64
[ 3289.303250] mtd_stresstest: scanning for bad eraseblocks
[ 3289.420267] mtd_stresstest: scanned 2048 eraseblocks, 0 are bad
[ 3289.426534] mtd_stresstest: doing operations
[ 3289.431031] mtd_stresstest: 0 operations done
[ 3339.606972] mtd_stresstest: finished, 1000 operations done
[ 3339.612992] ========================================
当mtd_stresstest测试发生操作错误时，会退出并答应错误信息，示例如下：
[root@AT8XXX ~]# dmesg |grep mtd_stresstest
[591404.676252] mtd_stresstest: MTD device: 9
[591404.680577] mtd_stresstest: MTD device size 268435456, eraseblock size 131072, page size 2048, count of eraseblocks 2048, pages per eraseblock 64, OOB size 64
[591404.699798] mtd_stresstest: scanning for bad eraseblocks
[591404.715081] mtd_stresstest: block 78 is bad
[591404.723850] mtd_stresstest: block 159 is bad
[591404.812382] mtd_stresstest: block 1752 is bad
[591404.832925] mtd_stresstest: scanned 2048 eraseblocks, 3 are bad
[591404.839259] mtd_stresstest: doing operations
[591404.843859] mtd_stresstest: 0 operations done
[591459.037353] mtd_stresstest: 1024 operations done
[591510.529876] mtd_stresstest: 2048 operations done
[594847.430017] mtd_stresstest: error: write failed at 0xf964000
[594847.436350] mtd_stresstest: error -5 occurred
更多mtd test的信息参考：http://www.linux-mtd.infradead.org/doc/general.html
