Difference between revisions of "BootLoader"

Revision as of 14:21, 4 April 2008

Introduction

This page describe the U-Boot installation/usage in the Armadeus context.

Build U-Boot

Build process is now part of the Armadeus automated build (see Install Armadeus software). To only build U-Boot you can launch:

$ make u-boot

Compiled binary files will be put in the buildroot/binaries/armadeus/ subdirectory.

• u-boot.bin is a binary image file that can be downloaded and flashed from U-Boot itself (see below)
• u-boot-brec is a boostrap record file compatible with the Freescale bootstrap inside the i.MXL.

The following informations are only kept here for historical reasons and only usefull for a manual build process.

• Download Das U-Boot source code archive from: http://sourceforge.net/project/showfiles.php?group_id=65938
• Uncompress it:

   tar jxvf u-boot-1.1.6.tar.bz2

• Get Armadeus patches in armadeus tree armadeus/buildroot/target/device/armadeus/u-boot/patches and copy it to the U-Boot directory.
• Go inside the U-Boot directory and apply the patches (here for u-boot-1.1.6):

   patch -p1 < 100-apx9328.patch
   patch -p1 < 101-u-boot-apx9328.patch
   and so on..

If you have a 8 or 16MB apf9328 board, edit the include/configs/apx9328.h. look for a #define SDRAM_xxxMBIT change it to a:

   * #define SDRAM_64MBIT /* for 8MB */
   * #define SDRAM_128MBIT /* for 16MB */
   * #define SDRAM_256MBIT /* for 32MB */

Then build U-Boot:

   make apf9328_config
   make

this produce u-boot.bin and u-boot.brec files described hereabove.

Install or restore from scratch

If your Armadeus board doesn't boot anymore (flash content erased or dammaged), you will have to use the bootstrap mode of the i.MX.
The uboot_recover python script is used to flash an uboot version.
This tool is located in the armadeus/software/uboot_recover folder of the armadeus project tree.
Take a look a the INSTALL file the first time you want to use the recover tool.
Remark: the serial port must support a baud rate of 57600 bps per second.

Modify your environment variables

There is a set of variables you can customize to your needs. The commande printenv show you most of them and their current state. Use the command setenv to change one of these variable. For instance:

setenv ipaddr 192.168.0.3

Use the command saveenv to save the state of your environment variables in flash memory.

In order to use network features with u-boot you have to set the network environment variables:

setenv netmask 255.255.255.0 (default value should be fine in most situations)
setenv ipaddr 192.168.0.3 
setenv serverip 192.168.0.5 (the IP adresse of your tftp host server to download update files )
setenv rootpath "/tftpboot/root" (to boot linux over nfs)

You can use the dhcp command to configure these variable from your dhcp server. Probably you will have to adjust the serverip variable manually.

BIOS> dhcp
dm9000 i/o: 0x15c00000, id: 0x90000a46
MAC: 00:0e:32:00:00:01
operating at 100M full duplex mode
BOOTP broadcast 1
DHCP client bound to address 192.168.0.3
BIOS>setenv serverip 192.168.0.5
BIOS>saveenv

Do not forget to save your changes in flash with saveenv to have them available at power up.

Update U-Boot

There are two steps to update u-boot:

• 1] Load the new u-boot code in RAM

You can use the following commands to download U-boot. With ethernet and a tftpboot server:

   tftpboot 08000000 /tftpboot_path_to_buildroot/u-boot.bin

With ethernet and a nfs server:

   nfs 08000000 host_ip_addr:/nfs_path_to_buildroot/u-boot.bin

With the kermit and a serial line

   loadb
   <CTRL><ALT GR>\
   c
   send path_to_buildroot/u_boot.bin
   c

• 2] Transfer code from RAM to Flash memory

There is a simple u-boot command/script to do that:

   run flash_uboot

Advanced Linux Boot

The command "boot" is the common way to run linux from flash memory. This command is equivalent to the macro:

   run jffsboot

This is the default command stored the u-boot variable: bootcmd.

   bootcmd=run jffsboot

U-boot also supports the commands to boot from a network or a sd/mmc card.

• nfs boot

   run nfsboot

This command boots linux rootfs from an nfs server. Change the u-boot variables serverip and rootpath to fit with your host pc.

   serverip=192.168.0.2
   rootpath="/tftpboot/root"

• mmc boot

   run mmcboot

This command boots linux rootfs from an sd/mmc memory card. Adapt the variables: mmcroot and mmcrootfstype to your extension card boot partition.

   mmcroot=/dev/mmcblk0p1
   mmcrootfstype=ext2

Customize the flash memory organization

TBD

Booting Linux

The Install Armadeus software on target provide some information to install linux on Armadeus board

Customize Linux boot mode

Typical Kermit (.kermrc) config file

set line /dev/ttyS0
set speed 115200
set carrier-watch off
set handshake none
set flow-control none
robust
set file type bin
set file name lit
set rec pack 1000
set send pack 1000
set window 5
set transmit linefeed on

Links

• http://www.denx.de/wiki/DULG/Manual