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How to set environment variables for TFTP boot?

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Hi,

I want to make L138 LCDK board with TFTP boot. I am new to L138 LCDK.

For the factory default u-boot settings, SW1 is: SW1: 1:OFF; 2:ON; 3:ON; 4:ON

I get the following procedures description, but I do not understand some of it.

Loading and Running Linux Kernel

The U-Boot comes with a set of default environment variables. Using those variables simplify several ways to boot kernel. Use the following command to set the default environment variables:

>env default -f –a
>saveenv

U-Boot supports three ways to boot kernel and is configured through 'boot' env variable. For each of this method, the boot env variable value to be used is provided in parenthesis.

  • tftp kernel and initrd ramfs (ramfs);
  • tftp kernel and use nfs mounted filesystem (net);
  • using ubifs (ubi);

You would need to add a few more variable specific to you setup:

  • serverip - IP address of your tftp server
  • tftp_root - Relative path from tftp server root directory where the image files are stored
  • boot - one of three ways to boot kernel (ramfs, net, ubi)
  • nfs_root - root directory exported by the NFS server (where the rootfs tar file was untarred)

Other defaults may be changed as needed. By default, these are set to use the image names from the Release. However for Preempt RT Full images, change the following env variables (applicable only for tftp boot of Linux and DTB):-

>setenv name_kern
>setenv name_fdt

Below is the variables I get. I do not see any of (ramfs, net or ubi) below. How to set tftp needed parameters to get a TFTP boot (I mean SD card does not need at all).

Thanks,

////////////////////////

U-Boot > setenv name_kern
U-Boot > pri             
baudrate=115200
bootargs=console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootwait ip=off
bootcmd=if mmc rescan 0; then if fatload mmc 0 0xc0600000 boot.scr; then source 0xc0600000; else fatload mmc 0 0xc0700000 uImage; bootm c0700000; fi; else sf pro
be 0; sf read 0xc0700000 0x80000 0x220000; bootm 0xc0700000; fi
bootdelay=3
bootfile="uImage"
ethact=DaVinci-EMAC
ethaddr=00:00:a0:00:fb:c7
stderr=serial
stdin=serial
stdout=serial
ver=U-Boot 2010.12 (May 07 2012 - 16:09:45)

Environment size: 496/65532 bytes
U-Boot >


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