u-boot启动Linux内核的几种方式

SDRAM

This method downloads the kernel and ramdisk image from ethernet using TFTP into SDRAM, then boots the kernel image from SDRAM. Use the following settings for U-Boot environment variables bootargs and bootcmd and reboot the DUT:

    U-Boot> setenv bootargs mem=32M console=ttyS2,115200n8 root=/dev/ram0 rw initrd=0xc1180000,4M ip=dhcp eth=${ethaddr}
     U-Boot> setenv bootcmd 'tftp 0xc0700000 uImage; tftp 0xc1180000 ; bootm 0xc0700000'

1. 仅使用tftp服务器, 使用文件系统。
    u-boot > setenv bootcm "tftp 0xc0700000 uImage; tftp 0xc1180000 ramdisk-base.gz; bootm 0xc0700000"
    u-boot > setenv bootargs "mem=32M console=ttyS1,115200n8 root=/dev/ram0 rw initrd=0xc1180000,4m ip=192.168.1.222"
     u-boot > saveenv

2. 使用tftp，nfs文件系统来启动。
    bootargs=root=/dev/nfs rootfstype=nfsroot rw noinitrd nfsroot=192.168.1.63:/home/leijinliang/arm/nfs/omapl138evm/arago-rootfs nolock ip=192.168.1.222 mem=32M console=ttyS1,1152
00n8
    bootcmd=tftp 0xc0700000 uImage; bootm 0xc0700000