View source for DHT-Walnut U Boot

== U-Boot 1.1.4 ==

Information on U-Boot can be found at [http://u-boot.sourceforge.net/]

The source for U-Boot 1.1.4 is downloadable from ftp://ftp.denx.de/pub/u-boot/u-boot-1.1.4.tar.bz2

Here is a patch that makes it work on the DHT-Walnut: [http://www.farnsworth.org/linuxppc/u-boot-dht-walnut-df2.patch u-boot-dht-walnut-df2.patch].

A binary that can be copied to the DHT-Walnut flash at 0xfffc0000 is available here: [http://www.farnsworth.org/linuxppc/u-boot-1.1.4-df2.bin u-boot-1.1.4-df2.bin]

Changes since u-boot-1.1.4-df1.bin:
* A default ethaddr is now set: de:ad:be:ef:00:00
* The ethaddr can be changed as often as you like.  Use: ''setenv ethaddr be:ef:be:ef:be:ef ; saveenv''
* Only the first two memory banks of a DIMM are used.  This allows us to use (half of) double-sided DIMMS.

Some things to note when changing from ppcboot to U-Boot:
* Default baudrate is 115200.
* Occupies flash addresses 0xfffc0000-0xffffffff  (256MB).
* Maintains two copies of environment data, primary copy at 0xfffb0000, backup copy at 0xfffa0000.

== Installing U-Boot 1.1.4 on the DHT Walnut ==
* Boot the board and bring it to the ppcboot (or U-Boot) console prompt.

* Download the new bootloader [[[Media:u-boot-1.1.4-df2.bin]] u-boot-1.1.4-df2.bin] into RAM:
** Using Kermit (you'll need a terminal emulator that supports the kermit file transfer mode):

  => ''loadb 800000 115200''

<pre>## Switch baudrate to 115200 bps and press ENTER ...
## Ready for binary (kermit) download ...
## Start Addr      = 0x00800000
## Switch baudrate to 9600 bps and press ESC ...
</pre>

** or tftpboot (requires a tftp server and setting the environment variables ethaddr, ipaddr and serverip)

  => ''tftpboot 800000 u-boot-1.1.4-df2.bin''

<pre>Using ppc_4xx_eth0 device
TFTP from server 192.168.1.1; our IP address is 192.168.1.44
Filename 'u-boot.bin'.
Load address: 0x800000
Loading: ####################################################
done
Bytes transferred = 262144 (40000 hex)
</pre>

* Verify that the download was received correctly (crc should be 0xd3cef189):

 => ''crc 800000 40000''

<pre>CRC32 for 00800000 ... 0083ffff ==> d3cef189
</pre>

* Unprotect the last 4 sectors:

 => ''protect off fffc0000 ffffffff''

<pre>Un-Protected 4 sectors
</pre>


'''From this point on, do *not* power down the board, and type *very* carefully.
This is the critical section.'''

* Erase the last four sectors:

 => ''erase fffc0000 ffffffff''

<pre>Erase Flash from 0xfffc0000 to 0xffffffff
Erasing sector fffc0000
.Erasing sector fffd0000
.Erasing sector fffe0000
.Erasing sector ffff0000
. done
Erased 4 sectors</pre>

* Copy the new bootloader into flash:

 => ''cp.b 800000 fffc0000 40000''

<pre>Copy to Flash... done
</pre>

* Verify that the image is correct (crc of u-boot-1.1.4-df2.bin is 0xd3cef189).

 => ''crc fffc0000 40000''

<pre>CRC32 for fffc0000 ... ffffffff ==> d3cef189
</pre>

'''End of critical section.  Congratulations'''
* Reset the board and see that the new version booted
*** Don't forget to change your baud rate to 115200

 => ''reset''

<pre>
U-Boot 1.1.4 (Feb 16 2006 - 17:15:06)

CPU:   AMCC PowerPC 405GP Rev. E at 266.640 MHz (PLB=66, OPB=33, EBC=33 MHz)
       Internal PCI arbiter enabled, PCI async ext clock used
       16 kB I-Cache 8 kB D-Cache
Board: DHT Walnut
I2C:   ready
DRAM:  128 MB
FLASH: 512 kB
PCI:   Bus Dev VenId DevId Class Int
        00  04  105a  0d30  0101  1d
In:    serial
Out:   serial
Err:   serial
Net:   ppc_4xx_eth0
IDE:   Bus 0: OK
  Device 0: not available
  Device 1: not available
BEDBUG:ready
</pre>


You will see a message like : *** Warning - bad CRC, using default environment
That's normal.  It will go away after you issue a ''saveenv'' command.

This bootloader works well with the 2.6 Linux kernel available [wiki:DHT-Walnut2.6LinuxKernel here].

Please let me know of any success or issues you encounter.  [mailto:dale-elinux@farnsworth.org dale-elinux@farnsworth.org]

[[Category:DHT-Walnut]][[Category:U-Boot]]