Linux on a winterm

Image available

2005-10-31T11:55:00.000Z

I re-created (most of) the code that I lost. An image is available here.

Deleted the code!

2005-06-17T12:07:00.000+01:00

Whilst upgrading my home server to debian-sarge I managed to loose all the source for the winterm project Argh!
Luckily I had some of it saved elsewhere, but not the latest version of alios. So, I had to re-construct this. I also lost the source for the kernel module.
Re-creating alios proved to be a real pain. Alios would boot, load the kernel and then reset - going into an endless loop. This took me ages to track down until I found that the KERNEL_CS location had changed in the kernel source! This is reference from within alios, making it jump to the wrong location. (During the server upgrade, I went from a 2.4.x kernel to 2.6.x)

Video and ROM

2005-01-27T14:12:00.000Z

Lots of stuff working now!
I changed alios to copy the VGA bios from the ATMEL flash to 0xF000. Now alios can call the bios and initialise the video!
Next problem was getting the keyboard to work. I eventually found that I needed to send a self test command to the keyboard controller. After that Linux found it and took over.
So now, we have a working VGA console. Only problem is, I can't get a good framebuffer working. I can only use the 16 colour vga one, as the GD5440 framebuffer needs a PCI bios :(
Now to the Intel Flash. I found that the MTD drivers will read and write this, once I've mapped it into physical memory. The flashcp program will write to it, but only for the 1st 3 erase blocks. This had me stumped for a long time - eventually i found that it was because I didn't map all of the flash into memory - doh!
So now I can put the kernel and initrd into the Intel flash and now the winterm boots without a PCMCIA card!

Accessing the internal ROMS

2005-01-17T10:39:00.000Z

I've now managed to read data from 2 of the 3 internal Flash ROMS
This is done by using the Memory windows to map the ROMS into CPU address space.
The Intel 2M byte is connected to ROMCS1 and the 4M byte Toshiba is connected to ROMCS2
The 256Kbyte Atmel is connected to ROMCS0

Update: I have now programmed Alios into the Atmel Flash so now the system starts to boot from internal ROM! Now need to burn the kernel and initrd images into the intel flash and boot it.
I've sucessfully read the intel flash using the linux mtd subsystem, but as yet i can't program it.
I think I need to write some software to program it (similar to the wrflash prog supplied with alios).

NFS is working

2004-10-19T16:32:00.000+01:00

Finally got NFS working. I can't use locking over nfs, as I don't have the portmapper on the winterm. But this isn't really a problem, as I only want to use NFS for read-only.
I've created a busybox initrd which does the following on startup:

mount nfs share from fileserver
run setup script from nfs share, it its there. This allows me to make mods to the system without reflashing the PCMCIA card.
run telnetd
run httpd

I now have the basis of a working system. Next step is to try and extract the data from the other flash ROMS. To do this, I need to understand more about how the ROMS are mapped into the address space

Network is up!

2004-10-17T22:56:00.000+01:00

Ok, it turned out that my assembler code was wrong for the external chip selects.
(why do we have at&T and Intel mnemonics with the args in different orders?)
Anyway, I fixed the code and now the external devices work.
I have 2 serial ports + network.
Switched over to using a busybox initrd so that I can fit more in.
Can't get the sound card to work yet, but at least the network is up :)

Enabling external IO devices

2004-10-15T15:25:00.000+01:00

Contacted Vincent Crabtree about his project to port Linux. He told me about IDA which is a great interactive dissasembler. he also sent me his partially disassembled ROM.
From this, I see that alios is missing loads of CSC configuration, so I implemented this and tried again.
What I now have is:

Internal UART as com2
Enable GP_CSA and GP_CSB - external ISA chip selects
This required mods to the linux kernel and the initrd image and now I have the kernel booting again, but still no external devices :(

Booting Linux

2004-10-15T11:59:00.000+01:00

After sorting the memory check in alios, Linux now boots off the flash card!
This is encouraging. Since the winterm uses fairly standard pc components, the network drivers should be available...
But I can't get the network drivers to work. For some reason, the network card does not appear to be responding correctly at port 0x300

Links

2004-10-06T13:09:00.000+01:00

Similar project, on 3315 here

First Boot

2004-10-06T11:48:00.000+01:00

Having programmed the card, I need to get the winterm to boot from it rather than internal ROM.
The docs say that you need to set CFG2 to 1 to disable internal ROM and map the PCMCIA slot to ROMCS0. A bit of hunting around the ciruit board, and it looks like this CFG2 is wired to one of 2 jumpers near the PCMCIA slot. Time for a bit of trial and error:

No flash inserted, short jumper xx - no boot :)
No flash inserted, short jumper yy - no boot :)
Insert flash, short jumper yy - no boot :(
Insert flash, short jumper xx - Alios Boots! :-)

So, alios boots, and starts displaying data on serial 1. Linux boots, but the RAM size is wrong. Alios shows 10MB, whereas WinCE reports 24MB!
The mem report shows 16 bit wide DRAM, which seems a bit odd. So, a quick look at the alios code reveals that it is set for matrix keyboard enabled, which limits dram width to 16bit.
Disabling matrix keyboard, and re-trying reports 24MB 32 bit RAM, plus a small amount in bank 3. This causes Linux to fail, as There isn't really RAM in bank 3.
Back to the docs...
Here I see that bank 3 may be set to an illegal configuration, during the RAM check. If this is the case, then bank 3 must be ignored.
The Alios code does not make this check (as far as I can see), so I need to add this in.

Flash Card problems (and solutions)

2004-10-06T11:31:00.000+01:00

Ok, so I managed to buy 4 linear flash cards from ebay. They are Centennial 2MB devices. The alios site gives brief details of how to load alios onto a card, so I thought this would be easy!
I have a hp omnibook 6000,with redhat 7.3 so I tried to use this to program the cards - no luck! Kept getting lots of 'cannot allocate memory' errors and segmentation faults when writing!
After lots of messing around, I got it to work as follows:

Rebuild the 2.4.18 kernel, with PCMCIA support disabled
Get the stand-alone PCMCIA package from sourceforge.
Build this, then modify the /etc/sysconfig/pcmcia file to use the standalone PCIC controller, rather than yenta_socket

After all this, It works! I can now program the cards sucessfully.
One note: I could not use the method specified with the alios source. Instead, I generate a 2MB image on disk, then write the whole image to flash, using a 128Kb block size. This works fine.

Initial Work

2004-10-06T11:24:00.000+01:00

Built an interface to read/program the ATMEL flash. I believe that this stores the BIOS.
Interface uses a 8255 board and needs an ISA bus machine. My only Linux machine with ISA is on it's last legs!
Interface doesn't seem to be too reliable, but I have managed to dump the ATMEL image to disk.

Found the AMD docs for the SC400 at here .
Looked at things to replace the ROM. Netboot? Then found alios. This seems to do exaclty what I need - i.e. boot Linux on an SC400. but it needs a linear flash card.

Aims

2004-10-06T11:19:00.000+01:00

My aim is to get Linux running on a wyse 2315SE Winterm.
I have 3 of these devices. They have:

AMD Elan SC400 Microcontroller
24MB DRAM
Flash ROM(1 intel part, 1 ATMEL part)
PCMCIA socket
Graphics Controller
Ethernet
2xSerial
1xParallel
Keyboard and Mouse Ports

I would like to get the linux running, with the ethernet card.
Applications:
X-Term
Audio Player (mp3/wav)
Portable wireless Audio player (using WiFi card in the PCMCIA socket)