Difference between revisions of "Flameman/dht-walnut"

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(other rootfs)
(Firnware Bootloaders)
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= Firnware Bootloaders =
= Firnware and Bootloaders =
* ppcboot (not suggested)
* ppcboot (not suggested)
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about issues, and ideas, they are also reported here [[Flameman/dht-walnut/rootfs#issue]]
= rootfs =
= rootfs =

Revision as of 03:00, 31 January 2010




please note this page is actively being updated, it is merged from the old version of wiki. so keep patient, i will rewrite this documentation as soon as possible

in case you need a pdf copy of the old doc, or if you need attachments feel free to ask me for them ( flameman, email speeder@alice.it, msn mr.ddc@hotmail.com)

about the jtag software: the one provided with the url will not work 'cause they remove the support for amcc44x. In case you need this software i stored the old version here, so feel free to ask me about.


The Target-goal of this page is

  • install gentoo-ppc32 into harddisk
  • make the board able to boot from it
  • describe how to build a jtag cable (to debug and recover from "Brickage")
  • describe something useful with you can do with the board
  • describe other Operating System avalaible for the board

logical steps about installing gentoo

  • add the JTAG connector at J10 (you could skip it, it is suggested)
  • build the JTAG cable (you could skip it, it is suggested))
  • replace the bootloader with ppcboot 1.1.6/U-boot 1.1.4
  • make partitions on the Hard Disk
  • populate them
  • set the bootloader environment to boot from the Hard Disk

People you could contact if you need help

  • flameman, i'm currently use this board for a project, email
    • msn daredevil-coder@hotmail.it
    • email flamemaniii@gmail.com
    • irc.nick flameman (channel #edev, #gentoo-ppc)
  • you ... if you want ;-)

About the board

DHT-Walnut is a shortened name for the Digital Home Technologies PCB 01070201 Rev. 1.1.

The DHT-Walnut board is based on the AMCC-Walnut (still available, and still expensive :P). It is a more improved board described at www.amcc.com.

A "walnut" searching will inform about schematic and software.

Also keep attention @ DENX: they have developed a lot for the AMCC-Walnut board, and you could find a linux patch for your problem, prettier documentation, developer suit, and much more: in case, you are suggested to have a look to their web pages.

you could find it on ebay, search for "walnut", or "powerpc"

MIND UP the differences between "DHT WALNUT" and "AMCC WALNUT" (ALSO CALLED "IBM WALNUT")

Where to find/buy the board

ebay, the seller "knktechequipment" can provide it

his auctions look like this:

Auction title: PowerPC 405 GP 266MHZ, with Linux, 32MB RAM Item number: 380085056864 Seller: knktechequipment( 935Feedback score is 500 to 999) Member is a PowerSeller Feedback: 100 % Positive Member: since Jan-19-04 in United States

Starting bid: US $35.00 Standard Flat Rate Shipping Service Service to United States Ships to: Worldwide Item location: Dallas, Texas, United States Payment methods: PayPal (preferred) Tested, In Good Working Order. Please check our store for more items Interfaces:

   * Ethernet
   * IEEE 1394 “Firewire”
   * RS-232
   * IDE
   * PCI

Operating System : Embedded Open Source Linux on 4Mbit Flash chip Comes with a copy of the Boot Loader

  • other place where to find this board ?



The board consists of:

  • CPU PowerPC 405GP running at 266mhz
  • RAM PC133 SDRAM slot, currently, only supports single sidded DIMMs
  • LAN On-chip 405GP ethernet, board doesn't have an ethernet MAC address (the monitor/bootloader is able to fix it)
  • UART DCE serial port, speeds up to 230k, only tested to 115200bps
  • PCI two pci slots, keyed for 5V only cards
  • IDE Promise Technologies PDC20265 IDE
  • ROM 512k of boot flash, AMD 29LV040B (amd29lv040b.pdf), soldered on the PCB, if you like to use a socket you have to consider the bootloader will check for the flash manufactor ID, so or you replace the 29LV040B with an other socked-29LV040B, or you have to modify the bootloader
  • POWER the board need to be 12v dc powered 2A max, it is able to feed the hard disk
  • System PCB 6.00" x 7.5" board size
  • RTC the real time clock chip is missing
  • RAM 32M PC133 SDRAM DIMM, the board has issues with more than 128M: if you inspect the pcb, you will see that the DIMM connector has same pin missing, this is the reason why you can't use DIMM bigger than 128M
  • PCI IEEE-1394 card supported by OHCI driver
  • PCI additional ethernet board needed cause the on board ethernet is implemented by the IBM-ppc-405GP, for example netbsd is not able to drive it, so in case you need an additional board, the one provided with DHT is good enough
  • FIRMWARE PPCBoot v.1.1.2 in flash (it has issues with environment, it need to be replaced with a gooder one)

Memory Locations

memory map of the board will be added as soon as possible

addr begin addr end area
40000  ?? ram, userspace
400000  ?? ram, userspace
0xef600700 0xef600700+4 PPC405GP, GPIO output register
0xef600704 0xef600704+4 PPC405GP, GPIO Tri-State register, Controls if pin is active when high.
0xef600718 0xef600718+4 PPC405GP, GPIO Open Drain register. Controls if pin is an open drain or active output.
0xef60071c 0xef60071c+4 PPC405GP, GPIO Input register. synchronized with OPBClk
0xFFF80000 0xFFFFFFFF 512K flash
0xfff80000 0xfff9ffff flash, may contains any user code
0xfffa0000 0xfffaffff flash, bootloader data
0xfffb0000 0xfffbffff flash, bootloader data
0xfffc0000 0xffffffff flash, bootloader, uboot has TEXT_BASE = 0xFFFC0000, 40000
0xfffffffc 0xfffffffc+4 flash, PPC405GP boots from this location ???
 Memory Area    Address Range Mapped   Size  Number of Level 2 pages
     Local Memory   0 - Ram size           32MB  8
     PCI Memory     0x80000000-0x83FFFFFF  64MB  16
     PCI IO Regn 1  0xE8000000-0xE800FFFF  64K   1
     PCI IO Regn 2  0xE8800000-0xE88FFFFF  1MB   1
     PCI CFG        0xEEC00000-0xEEC00FFF  4K    1
     PCI IACK       0xEED00000-0xEED00FFF  4K    0 *
     PP Bridge      0xEF400000-0xEF400FFF  4K    1
     UART IO Space  0xEF600000-0xEF600FFF  4K    0 *
     NVRAM Space    0xF0000000-0xF0001FFF  8K    1 (only on ibm-walnut)
     Flash          0xFFF80000-0xFFFFFFFF  512K  1

the u-boot image "sits" at the end of the flash, the 4xx PPC's boot from location 0xfffffffc, so the bootloader needs to be located at the end, so if u-boot is 256kbyte then it is located 0xfffc0000 ... 0xffffffff

the dht-walnut flash memory mapped, it's mapped via the 405gp EBC (external bus controller)


about the memory & the MMU

PowerPC Architecture - Memory Management Unit (MMU)

The PowerPC 405 supports 4 GB of flat (non-segmented) address space. The Memory Management Unit (MMU) provides Address Translation, Protection Functions, and Storage Attribute Control for this address space. The MMU supports demand-paged virtual memory using multiple page sizes of 1 KB up to16 MB. When supported by system software, the MMU provides the following functions:

  • Translation of the 4 GB logical address space into a physical address space
  • Independent enabling of instruction translation and protection from that of data translation and protection
  • Page-level access control using the translation mechanism
  • Software control over the page replacement strategy
  • Additional protection control using zones
  • Storage attributes for cache policy and speculative memory access control

The Translation Look-aside Buffer (TLB) is used to control memory translation and protection. Each one of its 64 entries specifies a page translation. It is fully associative and can simultaneously hold translations for any combination of page sizes. To prevent TLB contention between data and instruction accesses, a 4-entry instruction and an 8-entry data shadow TLB are maintained by the processor transparently to the software. Software manages the initialization and replacement of TLB entries.

The PowerPC 405 includes instructions for managing TLB entries by software running in privileged mode. This capability gives significant control to system software over the implementation of a page replacement strategy. Storage attributes are provided to control access of memory regions. When memory translation is enabled, storage attributes are maintained on a page basis and read from the TLB when a memory access occurs. When memory translation is disabled, storage attributes are maintained in storage attribute control registers. A zone protection register (ZPR) is provided to allow system software to override the TLB access controls without requiring the manipulation of individual TLB entries.


  • uboot (tested on 1.1.4) has issues in PCI/DMA initialization. More will be post in the future
i found a problem using a pci sound card in the DHT-WALNUT.
It has been correctly recognized by the kernel, the DMA feature (ppc405-dma) is setted, but the card is not working.

somebody says it is a bug, somebody says ppcboot solves the problem inizializing the pci in the correct way. I don't know, i'm using the uboot v1.1.4 and it is not working

also have a look to this

<> but i already thought so when i saw the "pci long" output
<> no BAR was assigned with an address
<> this was different some time ago
<> could be something changed in the last few months in the common pci support
<> i'll check with an ex-kollegue and let you know
<> this will take till beginning of next week though
<> hey, i just checked the source (sometimes helpful)
<> you just need to enable the host bridge configuration via an env variable
<> => setenv pciconfighost yes
<> then
<> => saveenv
<> => reset
<> after this reset the BAR1 will be configured:
<> => pci long
<> Scanning PCI devices on bus 0
<> Found PCI device 00.00.00:
<>   vendor ID =                   0x1014
<>   device ID =                   0x0156
<>   command register =            0x0006
<>   status register =             0x2210
<>   revision ID =                 0x01
<>   class code =                  0x0b (Processor)
<>   sub class code =              0x20
<>   programming interface =       0x00
<>   cache line =                  0x00
<>   latency time =                0x87
<>   header type =                 0x00
<>   BIST =                        0x00
<>   base address 0 =              0x00000000
<>   base address 1 =              0x80000008

could you help me to understand how to plug a soundcard ?

Images of the board


see more detailed photo dht-walnut-ppc405-top


The BEST solution is to equip your lab with the bdi2000. This hardware is expensive a lot, 'cause it is not a simple download cable, it's a professional debugger

For this dht-walnut project it has been used "OCD Commander is macraigor's free debugger software", that i'm going to illustrate


Firnware and Bootloaders

  • ppcboot (not suggested)
  • U-Boot (it can't load kernel >=2.5.25)
  • U-Boot-kanojio (under development, it will be able to boot kernel >2.6.25, see below)


about issues, and ideas, they are also reported here Flameman/dht-walnut/rootfs#issue


storage device: HardDisk, microdrive or Compact Flash, put a rootfs on it



Operating System available for this board


  • Netbsd has a port for "IBM PowerPC 405GP based Walnut evaluation board", this is not the DHT-Walnut, this is an other way to call the AMCC-Walnut (yes just to be confusing). Ok, it is not for DHT-Walnut, but this port could be (easealy / hardly) adapted to the DHT-Walnut with some work / over work

Hardware that is known to work with

  • see netbsd web, the hw could be (easealy / hardly) adapted to the DHT-Walnut with some work / over work



  • Version 2.4 (Mostly) working kernel binary and config from jbevren with matrox fbcon and usb input support. Current issues: USB keyboard input doesnt seem to work, but events reach /dev/input/event0
  • Version 2.6 working ... tested vanilla kernel, 2.6.24 (actually running)

boot from HD

Work In Progress

ppcboot/U-Boot provides only basic functionality to access Hard disks: you can print the partition table and read and write blocks (addressed by absolute block number), but there is no support to create new partitions or to read files from any type of filesystem. The current version of ppcboot-1.1.6 has a problem with writing to hdd, however, once the Linux kernel is loaded and the userland initialized, the hdd can be accesses normally through PIO and DMA modes. This may or may-not be fixed in the future.

As usual, you can get some information about the available IDE commands using the help command in ppcboot:

  => help ide      
ide reset - reset IDE controller
ide info  - show available IDE devices
ide device [dev] - show or set current device
ide part [dev] - print partition table of one or all IDE devices
ide read  addr blk# cnt
ide write addr blk# cnt - read/write `cnt' blocks starting at block `blk#'
    to/from memory address `addr' 

You may create the needed partitions by tftpbooting Linux and an appropriate userland, then use fdisk to partition the disk. Then reboot back to ppcboot.

ppcboot can be configured for DOS and Mac OS? type partition tables. Since ppcboot cannot read files from a filesystem you should create one (or more) small partitions (maybe 1 or 2 MB) if you want to boot from the "disk". (The size of these partitions will depend on how large your kernel and userland images are)

You should create the following partiton table:

 # fdisk /dev/hdx
 hde: hdx1 hdx2 hdx3 hdx4

/dev/hde1  ID=83   Linux <---- 2Mb, boot kernel, dd if=kernel of=here
/dev/hde2  ID=83   Linux
/dev/hde3  ID=83   Linux <----  root & usr
/dev/hde4  ID=82   Swap  <---- 32Mb, swap

You should also initialized /dev/hdx4 as swap space.
# mkswap /dev/hdx4
Setting up swapspace

check how ppcboot/U-Boot will recognize this partition table:
<pre> => ide part

* dd if=kernel.img of=/dev/hdx1

To boot from a disk you can use the diskboot command:

<pre> => help diskboot
diskboot loadAddr dev:part 

The diskboot command expects a load address in RAM, and a combination of device and partition numbers, separated by a colon. It then reads the image from disk and stores it in memory. We can now boot it using the bootm command [to automatically boot the image define the ppcboot environment autostart with the value =yes=].

 => diskboot 400000 0:1
ide_read dev 0 start 0, blocks 1 buffer at 3F9F8C0
## Valid DOS partition found ##

Loading from IDE device 0, partition 1: Name: hda1
  Type: PPCBoot
First Block: 63,  # of blocks: 8001, Block Size: 512
ide_read dev 0 start 3F, blocks 1 buffer at 400000
   Image Name:   DHT Kernel

=> bootm 400000 c00000
## Booting image at 00400000 ...
   Image Name:   DHT Walnut Kernel
   Image Type:   PowerPC Linux Kernel Image (gzip compressed)

=> setenv bootargs root=/dev/ram0
=> setenv autostart yes
=> disk 400000 0:1 \;\ diskboot c00000 0:2 \;\ bootm 400000 c00000
=> bootd

(i will post all my setenv)

The above procedure puts the userland image from the second partition into a ramdisk. If you would like the userland to be an ext2/3/rieser/xfs partition on the hdd do the following:

  • make the partiton table as above
  • put the kernel and small userland onto the first partitions as above
  • populate the root&usr partition with the appropriate files (gentoo-ppc32 distro)
  • change bootargs to "bootargs root=/def/hda3"
  • bootd to try out the new root, if it works ok, reboot back to ppcboot, change the bootargs again and saveenv
  • bootd and enjoy your new system.


=> printenv
ramargs=setenv bootargs root=/dev/ram rw
addip=setenv bootargs ${bootargs} ip=${ipaddr}:${serverip}:${gatewayip}:${netmask}:${hostname}:${netdev}:off panic=1
addtty=setenv bootargs ${bootargs} console=ttyS0,${baudrate}
update=protect off fffc0000 ffffffff;era fffc0000 ffffffff;cp.b 100000 fffc0000 40000;setenv filesize;saveenv
preboot=echo "ide.part.1th stores kernel rawimage"
bootcmd=run boot-disk ; bootm
setconsole_uart=setenv myconsole ${myuart},${baudrate}
setconsole_video=setenv myconsole tty video=${myvideofb}
setbootargs=setenv bootargs console=${myconsole} root=${myroot} init=${myinit}
bootargs=console=ttyS0,9600 root=/dev/hda4 init=/sbin/init
boot-tftp=tftpboot ${myboot_kernel_addr} ${myboot_file}
boot-disk=diskboot ${myboot_kernel_addr} ${myboot_diskpart}
ramrootfs=setenv bootargs console=ttyS0,9600 rdinit=/sbin/init init=/bin/bash
ver=U-Boot 1.2.0-g7882751c-dirty (Apr 14 2007 - 16:44:37)

Environment size: 1405/16379 bytes

Hardware that is known to work with

There is a list of the Hardware that is known to work (and not to work) with this board. Feel free to add, comment, feedback about it.

  • matrox millennium I/II
  • 3com-netcard
  • adaptec 2940
  • ...

Compile from sources

Linux 2.6 has issues in the source's tree: the dht-Walnut has been originally ported to arch=ppc, while the new kernel tree is around arch=powerpcc, for this reason you need to specify the right arch or your compiler will have issues. Developers will port everything to arch=powerppc in the future. Kernel 2.6.12 is free of this problem, newer than .12 have it.



version host target toolchain note compiled on ppc-7410, minerva arch=ppc, target=ppc 603/4 core gcc-4.1.2-glibc binutils-2.17 ramrootfs (uclibc) works great! no issues, no NPTL kernel
2.6.19 compiled on ppc-7410, minerva arch=ppc, target=ppc 603/4 core gcc-4.1.2-glibc binutils-2.17 ramrootfs (uclibc) works great! no issues
2.6.22 compiled on ppc-7410, minerva arch=ppc, target=ppc 603/4 core gcc-4.1.2-glibc binutils-2.17 ramrootfs (uclibc) works great! no issues
2.6.26 compiled on ppc-7410, minerva arch=ppc/powerpc, target=ppc 603/4 core gcc-4.1.2-glibc binutils-2.17 it does not compile!
2.6.30 compiled on ppc-7410, minerva arch=powerpc, target=ppc 603/4 core gcc-4.1.2-glibc binutils-2.17 it does not compile!

29-01-2010: i am using 2.6.22 for production

  • 2.6.25 ARCH=ppc -- boots
  • 2.6.25 ARCH=powerpc -- hangs before any output
  • 28..31 have ARCH issues (probably case it was not properly ported from PPC to POWERPC)
  • 32..33 unchecked, but they should have device name inversion bug + LZMA bug


2007: kernel 2.6.19 full tested and working (suggested for production, there are issue with this wiki upload page, so if you need this kernel, you could email me, i will send by emaul)

compiled with gcc-3.4.6, basically it is a vanilla, with a bit of my patches i added in order to avoid myself from the differences between a common "ppc" platform and .. the 405GP/walnut.

14-06-2009: new kernel 2.6.30 needs to be hardly tested (with gcc-4.3.*) and (maybe) patched anyway, advantages about

  • the new supported pci/usb hw
  • the new dynamic tickless
  • the ext4
  • the new networking stack and congestion mechanisms

30-10-2010: new kernel (>=2.6.25 need new bootloader)

Project: do something useful with the board

DHT-Walnut as N.A.S.


I turned a DHT-Walnut + 300Gb hard disk into a file server to have my data files connected and shared to the LAN (Local Area Network).

N.A.S. stands for Network Attached Storage. They are storage devices attached to the lan. A NAS should be able to be connected to every kind of network. It should use both the access protocols NFS (Network File System) and CIFS (Common Internet File System)

I only enabled NFS service in the kernel configure because i don't need CIFS. UNIX servers use NFS, while Microsoft systems use CIFS, fortunately i don't have any Microsoft systems here :P Gentoo is installed in the first little partition of the hard disk (it is PC-partition style, so you can only have 4 partitions). It runs openssh, telnet, ftp, tftp, and NFS. As the fact there is no RTC chip installed i added special /etc/init.d/clock-sync to set the local time. The scrips uses rdata to retrieve the current time of an other machine.

In the photo you could see the case i realized: the hard drive is connected to the opened door, the DHT-walnut PCD has been placed inside, the green LED has been used to the frontal case to say "the booting has been completed, the system is ready" (used the gpio hack provided in patches for the 2.6.16-rc3). The black platform is from sony playstation2 and is is only a nice way to have the case vertically seated.

Don't keep about the ALS4000 pci sound board plugged in the upper PCI bus. It has been plugged just to use the NAS as the giant (300Gb) ipod you have ever seen .... but this is an other story ....

Note: also scsi adaptec-2940 is working !!! i added 3x40Gb sca-scsi stored in a sun box

to be checked: sATA pci controller

please report any other working hardware here, or @ flamemaniii@gmail.com


thinking new things ... but it should be compatible with "free time constraints" =P