GNU/Linux on a Soekris net4801

This document is copyrighted © 2005 by Henrik Brix Andersen. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is available at http://www.gnu.org/copyleft/fdl.html.

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No liability for the contents of this document can be accepted. Use the concepts, examples and information at your own risk. There may be errors and inaccuracies, that could be damaging to your system. Proceed with caution, and although this is highly unlikely, the author(s) do not take any responsibility.

All copyrights are held by their by their respective owners, unless specifically noted otherwise. Use of a term in this document should not be regarded as affecting the validity of any trademark or service mark. Naming of particular products or brands should not be seen as endorsements.

I would like to thank pil.dk for sponsoring my work on this project. If you need hosting you should consider contacting them.

Feedback is most certainly welcome for this document. Send your additions, comments and criticisms to the following email address: <henrik@brixandersen.dk>.

The Geode SC1100 processor is an i586 class CPU with MMX (also referred to as Pentium MMX). You need to enable the kernel option listed below to support the CPU and architecture of the net4801.

If you intend to use the onboard IDE controller (HDD and/or Compact Flash) you will need the kernel options listed below. Please note that the Compact Flash is not hot-pluggable.

To enable the 3 ethernet ports of the net4801 you need the kernel options listed below.

To enable the USB port of the net4801 you need the kernel options listed below along with drivers for the devices you plan to attach.

To enable the two serial ports of the net4801 you need the kernel options below.

console=ttyS0,19200n8

serial --unit=0 --speed=19200 --word=8 --parity=no --stop=1
terminal serial

s0:12345:respawn:/sbin/agetty 19200 ttyS0 vt100

The GPIO of the net4801 is controlled through the PC87366 SuperI/O chip from Winbond/National Semiconductor. There is no in-kernel driver for controlling the GPIO yet, but Martin Hejl and Stanislav Meduna has written one. It doesn't play too well with the in-kernel SCx200 drivers, though. Jim Cromie has written a more generic GPIO driver for the PC87366 chip.

The error LED is connected to GPIO20 on the SC1100 processor. To control it from user-space you need the kernel option listed below.

You will need to create a device entry for the error LED using the command mknod -m 600 /dev/error_led c 254 20. You can then control the LED by echoing either 0 or 1 to the /dev/error_led device node.

To enable the hardware watchdog you need the kernel options listed below. You will also need a user-space utility such as watchdog.

To enable the temperature and voltage monitor of the net4801 you need the kernel options listed below.

You need to pass at least init=1 to the pc87360 driver or you wont get any readings. See Table 1 for a list of valid initialization levels. Beware that repeatedly sampling in9 will reduce battery lifetime, more information is available in the pc87360 file included with lm_sensors.

You will also need the user-space utility lm_sensors version 2.9.1 or newer. You should add contents similar to that of Figure 5 to /etc/sensors.conf.

The setup shown is partly based on the PC87366 datasheet and partly borrowed from Poul-Henning Kamp's env4801 utility since Soekris Engineering have yet to release any information about the external voltage dividers and recommended operating conditions. I have contacted Soekris Engineering about this, but I haven't heard anything from them yet.

chip "pc87366-*"

# Soekris net4801 configuration

# Written by Henrik Brix Andersen <henrik@brixandersen.dk>
# Latest version can be found at http://www.brixandersen.dk/

# The configuration is partly based on the PC87366 datasheet and
# partly borrowed from the env4801 utility by Poul-Henning
# Kamp <phk@phk.freebsd.dk>

# Datasheet: http://www.winbond.com/PDF/APCsheet/PC87366.pdf
# env4801:   http://phk.freebsd.dk/soekris/env4801/


# Voltage inputs
  ignore vid

  # Unknown
  # label in0     "avi0"
  ignore in0


  # Core Voltage, +2.0V
  label in1     "VCORE"
  set in1_min   1.9
  set in1_max   2.1


  # VCC, +5.0V
  label in2     "VCC"
  compute in2   @*2, @/2


  # Power Supply Input, +6.0V - +28.0V
  label in3     "VPWR"
  compute in3   @*20.1, @/20.1
  set in3_min    6.0
  set in3_max   28.0


  # +12V
  label in4     "+12V"
  compute in4   @*4.83, @/4.83
  set in4_min   11
  set in4_max   13


  # -12V
  label in5     "-12V"
  # If in10 on your net4801 doesn't have the 3.3V reference, use this
  # compute line instead:
  # compute in5   (@-3.3)*19.2+3.3, (@-3.3)/19.2+3.3
  compute in5   (@-in10)*19.2+in10, (@-in10)/19.2+in10
  set in5_min   -13
  set in5_max   -11


  # GND, 0V
  label in6     "GND"
  set in6_min   0
  set in6_max   0


  # Standby Voltage, +3.3V
  # Internally divided by 2
  label in7     "Vsb"
  compute in7   @*2, @/2
  set in7_min    3.0
  set in7_max    3.6


  # Supply Voltage, +3.3V
  # Internally divided by 2
  label in8     "Vdd"
  compute in8   @*2, @/2
  set in8_min    3.0
  set in8_max    3.6


  # Battery Backup Supply Voltage, +3.0V
  label in9     "Vbat"
  set in9_min    2.4
  set in9_max    3.6


  # Analog Supply Voltage, +3.3V
  # Internally divided by 2
  label in10    "AVdd"
  compute in10  @*2, @/2
  set in10_min   3.0
  set in10_max   3.6


# Temperature inputs
  ignore temp1
  ignore temp2

  # PC87366 Internal Temperature
  # PC87366 Recommended Operating Conditions: 0 - 70C
  # SC1100  Recommended Operating Conditions: 0 - 85C
  label temp3       "Temp"
  label temp3_crit  "Critical"
  set temp3_min      0
  set temp3_max     70
  set temp3_crit    85


  ignore temp4
  ignore temp5
  ignore temp6


# Fan inputs
  ignore fan1
  ignore fan2
  ignore fan3

You need to execute the command sensors -s at boot time to initialize the sensors. You can then run the command sensors to read the sensors.

To enable the Real Time Clock of the net4801 you need the kernel option listed below.