TI中文支持网使用的SDK为 ti-sdk-am335x-evm-08.00.00.00 ，想测试DDR3的稳定性，请问：
1. uboot中没有mtest命令，请问怎么添加?
2. mtest会自动避开uboot使用的内存区域吗？ 或者uboot自己使用的内存区域范围是多少？
uboot中输入"?"显示支持的命令如下，没有mtest：
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U-Boot SPL 2014.07-00110-gfb741e0-dirty (Jun 18 2019 – 14:49:28)
stone first
sdram init
reading args
spl_load_image_fat_os: error reading image args, err – -1
reading u-boot.img
reading u-boot.img
U-Boot 2014.07-00110-gfb741e0-dirty (Jun 28 2019 – 15:32:11)
I2C: ready
DRAM: 512 MiB
NAND: 0 MiB
MMC: OMAP SD/MMC: 0, OMAP SD/MMC: 1
reading uboot.env
** Unable to read "uboot.env" from mmc0:1 **
Using default environment
Net: <ethaddr> not set. Validating first E-fuse MAC
cpsw, usb_ether
Hit any key to stop autoboot: 0
U-Boot#
U-Boot# ？
Unknown command '？' – try 'help'
U-Boot# ?
? – alias for 'help'
askenv – get environment variables from stdin
base – print or set address offset
bdinfo – print Board Info structure
boot – boot default, i.e., run 'bootcmd'
bootd – boot default, i.e., run 'bootcmd'
bootm – boot application image from memory
bootp – boot image via network using BOOTP/TFTP protocol
bootz – boot Linux zImage image from memory
chpart – change active partition
cmp – memory compare
coninfo – print console devices and information
cp – memory copy
crc32 – checksum calculation
dfu – Device Firmware Upgrade
dhcp – boot image via network using DHCP/TFTP protocol
echo – echo args to console
editenv – edit environment variable
eeprom – EEPROM sub-system
env – environment handling commands
exit – exit script
ext2load- load binary file from a Ext2 filesystem
ext2ls – list files in a directory (default /)
ext4load- load binary file from a Ext4 filesystem
ext4ls – list files in a directory (default /)
false – do nothing, unsuccessfully
fatinfo – print information about filesystem
fatload – load binary file from a dos filesystem
fatls – list files in a directory (default /)
fatwrite- write file into a dos filesystem
fdt – flattened device tree utility commands
go – start application at address 'addr'
gpio – query and control gpio pins
gpt – GUID Partition Table
help – print command description/usage
i2c – I2C sub-system
iminfo – print header information for application image
imxtract- extract a part of a multi-image
itest – return true/false on integer compare
load – load binary file from a filesystem
loadb – load binary file over serial line (kermit mode)
loads – load S-Record file over serial line
loadx – load binary file over serial line (xmodem mode)
loady – load binary file over serial line (ymodem mode)
loop – infinite loop on address range
ls – list files in a directory (default /)
md – memory display
mdio – MDIO utility commands
mii – MII utility commands
mm – memory modify (auto-incrementing address)
mmc – MMC sub system
mmcinfo – display MMC info
mtdparts- define flash/nand partitions
mw – memory write (fill)
nand – NAND sub-system
nboot – boot from NAND device
nfs – boot image via network using NFS protocol
nm – memory modify (constant address)
part – disk partition related commands
ping – send ICMP ECHO_REQUEST to network host
printenv- print environment variables
reset – Perform RESET of the CPU
run – run commands in an environment variable
saveenv – save environment variables to persistent storage
setenv – set environment variables
sf – SPI flash sub-system
showvar – print local hushshell variables
sleep – delay execution for some time
source – run script from memory
spl – SPL configuration
sspi – SPI utility command
test – minimal test like /bin/sh
tftpboot- boot image via network using TFTP protocol
true – do nothing, successfully
usb – USB sub-system
usbboot – boot from USB device
version – print monitor, compiler and linker version
yongqing wang：
TI Tool(CCS Debug)提供AM335X DDR Tests ，使用里面的"DDR_ataTransferCheck" & "EDMA"测试
