Linux on the IBM RS/6000 40P model 6015 and 40P model 7020 HOWTO

The 40P series is a PowerPC maschine build from IBM, based
on the PReP design standard.
Most components of the 40P series are IBM-PC-like components. The
maschines have ISA and PCI slots, parallel and serial ports, with
the same IO-base addresses and interrupts like a standard pc.

This makes it much easier in some cases to port drivers, which are
originally made for a Intel-based PC. But there are some huge differences
between an intel based PC and the powerpc based 40P:
They way the expansion cards, like the Ethernetcard or the Graphicadapter
is addressed and used is different from the Intel-PC World. Next
thing is that cards for an intel based PC often have a Bios-Eprom,
which is used while a PC is booted up. This is made for a x86 compliant
processors and can't be used for PowerPC's.
On the IBM 40P thes detection and usage of the original expansion hardware
is inside the microcode (aka the PPC-bios). The Cards don't need to have
a bios-eprom or similar things.

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3.1 The IBM 40P Model 6015/7020

The IBM Modell 6015 and 7020 are based on the PReP Design and
have a 601 PowerPC-CPU with 60 Mhz.
Up to now, the only differnce between both maschines are the styles of the case
It looks like IBM sold the 6015 mostly as an Windows NT-Workstation and the 7020
as an AIX-Workstation.

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3.2 Mainboard

The mainboard of the 40P integrates following components:
onboard cpu (PPC 601 - 60 Mhz) (no socket!)
Memory Slots
floppydisk controller
2 serial ports
1 parallel port
A bridge to PCI-Cards and ISA-Cards (wired to one Slot which connects a PCI/ISA riser card)
SCSI Controller
Sound Card
powerup-slot
PS2 compatible keyboard connection
PS2 compatible mouse connection
powersupply-Connection

The powersupply-connection is the same one, which you can find on normal Intel-PC's
with AT-Formfactor motherboard. Even the powersupply-case is the same, so if your
powersupply on your 40P breaks, you can grab a standard supply from your local pc
dealer.

The Powerup slot is an expansion bay to make your 40P much faster.
IBM sold 2 different kind of Powerup-cards for 40P. One powerupcard is available
with Second level cache and other one is holding a PowerPC 604 (and disables
the onboard 601 cpu).
These powerup cards are very rare, but we have at least one guy who has a powerup
card with a 604. So more information will be added here in future.

Following Jumpers and Connectors are available on the board:

J3 - Internal SCSI Drive Connector
J13 - Speaker Connection
J14 - 2x8 Pin Connector - PowerPC Debugging Connection (Risc_Watch)
J15 - CD-Audio-connection
J17 - Reset Switch
J18 - Harddisk LED Connection
J20 - 3x1 pin with a jumper set to a white marking on the board , currently unkown
J21 - Connection to Case-fan
J22 - Power-On LED Connection
J23 - Key-Lock
J24 - 2x4 Pin Connection, currently unknown
J34 - 2x13 Pin Connection for the printer interface (parallelport)
J35 - standard PC Floppy connection

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3.3 Memory-Slots

The only kind of memory, which the 40P can use is DIMM format. The DIMMS must
be Fastpage-Mode and run with 5 Volts. These memory modules are normally not
found in intel based pc's and are pretty rare.
There are 6 memory banks. Most maschine have 8 Mbyte modules inside. It is
possible to mix these modules with modules, with more capacity.
maximal memory expansion is 192 Mb, so 6x 32 MB Modules.
most used machines have 4x 8 MB or 6x 8 mb.
The IBM Number of the 32MB Module is: 92G7213
At least Kingston is selling these Modules (Kingston KTM40P/32),
but they are quite expensive.

Here are two Pictures of the 8MB DIMM Module:

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3.4 Soundchip

The Soundchip which is used on the 40P is a Cirrus Logic CS4231.
The CS4231 was also producted by Analog Devices under the name AD1845.
Both chips are completly the same and luckly Analog Devices have some
more informations about the chip.

Here some links to the AD1845 from Analog Devices:
http://products.analog.com/products/info.asp?product=AD1845
http://www.analog.com/techsupt/application_notes/AN-404.pdf

Pinouts and functional blockdiagrams and a little programming example (in C) is
available here ftp://andrew.triumf.ca/pub and from the Homepage
of the author of this document.
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3.5 SCSI-Controller

The SCSI Controller onboard is a NCR 53C810. This is an Fast SCSI-II Controller,
which have an internal Connection for Drives inside the Case and a High-Density
Interface for external devices.

Hint: If you are building your own Kernel, be aware, that there are different
NCR/Symbios 7XX and 8XX drivers. The correct one is "NCR 8xx" and not the mixture
of 7xx/8xx.

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3.6 Official IBM PCI-Cards

Video-Adapters:

There are two major cards used in the 40P series:
The IBM S15 and the IBM E15. Both cards are OEM Products from
other companys, which are also used in intel pc's.

The IBM S15 is a Viper Pro PCI/VP from Diamond Computer Systems Inc.
Its using a Weitek P9100 Videochipset and an IBM Ramdac (IBM RGB525L).

The IBM E15 is a S3 Vision864 Videographic Card with an S3 Ramdac.

Currently the E15 Cards with the S3 Chip is the better choice, when
using Linux on the 40P, because there is Framebuffer Support for the
S3 Cards. When you have a Weitek P9100 Card, there is no support in
Linux today.
News: Sven built a S15 minimal-framebuffer driver, which allows to
use linux in a framebuffer-textmode. I works quite fine and I will
prepare boot-disks as soon as possible.

Other PCI Cards used by IBM's powerpcs:
The IBM GXT 120P is a Matrox Millenium I PCI Card.

The IBM GXT 130P is a Matrox G200 PCI Card.

Both GXT 120P and GXT 130P are not bootable from the 40P's
microcode (aka: the BIOS). You need an E15 or S15 as a primary card,
if you want to see the bootscreen.

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3.7 Official IBM ISA-Cards

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3.8 Alternative functional cards

If you need an IBM S15 or an IBM E15 Card, you can try to get alternative cards,
which are used in Intel-PC's.
We have tried:
Miro 20SD PCI Rev B, which is using the S3 Vision 864 and an S3 Ramdac (SDAC 86C716)
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4. Bios, Setup and Systemconfiguration

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4.1 While the system is booting

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4.2 SMS Diskettes

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4.3 Firmware Upgrade (Microcode Updates)

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4.4 Integrated Systemfunctions

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4.5 Resident Monitor (primitive micro-os)

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5. Booting a linux kernel

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5.1 Different ways to load linux

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5.2 Booting from Diskette

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5.3 Booting from Harddisk

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