[Qemu-discuss] Implementing CIO-DIO24 Parallel port in QEMU

[Chris Sadler]

Hello,

 

I am attempting to virtualize a legacy industry application under DOS in QEMU.  In order to make it work correctly, I have determined that I need to add support for a new device in QEMU, specifically this:  http://www.mccdaq.com/isa-data-acquisition/CIO-DIO24.aspx.  QEMU’s parallel port emulation does not support the correct memory register mapping for this device.

 

I have the necessary documentation of memory registers and port pinouts, etc.  I even have a physical device.  I have already read through the QDEV pdf and the qdev-device-use.txt documents.  I took a gander on the parallel.c file and some of the serial port examples in the /hw/char directory of the QEMU source code (this device is basically a parallel port, albeit a very non-standard one), but they are not very well documented.  My question is this: what exactly do I need to implement in order to be able to A) detect and use the hardware inside the guest machine, B) redirect output over an alternative medium (e.g. a named pipe) similar to how the current -serial and -parallel interfaces work, and C) start this with a command line argument?

 

I apologize in advance if this is the wrong place to ask this.

 

Thank you for your time; I appreciate any feedback.

 

Chris