boot linux over tftp and nfs.txt

1) Build u-boot with support Network, tftp and nfs
2) Check nfsv3 support in linux configs
3) Write u-boot to sd-card
4) On host run tftp and nfsv3 (see your distro wiki)
5) Create bootscript file. Example:
  setenv tftp_dir zed
  setenv nfs_rfs /srv/nfs/zed

  setenv bootargs ip=dhcp
  setenv bootargs ${bootargs} console=ttyPS0,115200n8 

  setenv nfs_ip 192.168.100.7
  setenv bootargs ${bootargs} root=/dev/nfs rootfstype=nfs nfsroot=${nfs_ip}:${nfs_rfs},port=2049,nfsvers=3,tcp rw loglevel=8 nfsrootdebug

  setenv bitstream_image 'fpga.bin'
  setenv bitstream_addr 0x4000000
  setenv bitstream_tftp 'tftpboot ${bitstream_addr} ${tftp_dir}/${bitstream_image}'
  setenv bitstream_load 'fpga load 0 ${bitstream_addr} ${filesize}'

  setenv devicetree_image system.dtb
  setenv devicetree_addr 0x2A00000
  setenv devicetree_tftp 'tftpboot ${devicetree_addr} ${tftp_dir}/${devicetree_image}'

  setenv kernel_image uImage
  setenv kernel_addr 0x3000000
  setenv kernel_tftp 'tftpboot ${kernel_addr} ${tftp_dir}/${kernel_image}'

  setenv phy_rst 'mw.w f8000008 df0d ; mw.w f8000140 00100801 ; mw.w f8000004 767b'
  setenv rset_phy 'run phy_rst'

  setenv boot_now 'bootm ${kernel_addr} - ${devicetree_addr}'

  run bitstream_tftp bitstream_load kernel_tftp devicetree_tftp rset_phy boot_now


6) Compile bootscript file by mkimage (uboot-tools package):
    sudo mkimage -A arm -O u-boot -T script -C none -a 0 -e 0 -n "t-Boot Script" -d bootscr.txt /srv/tftp/boot.scr

7) Copy uImage and devicetree.dtb to tftp_dir (see example on bootscript file)
    
8) Run board and go to U-BOOT

9) Change u-boot environment:   
    setenv ipaddr 192.168.100.6
    setenv serverip 192.168.100.7
    setenv t-addr 0x100000
    setenv t-boot 'tftpboot ${t-addr} boot.scr ; source ${t-addr}'
    setenv bootcmd 'run t-boot'
    saveenv


10) restart