[ag-automation] What's the recommended interface to x86-IO-space

[Claus Gindhart]

Our Kontron HW provides a number of HW functionalities (LEDs, Watchdog, Board 
configuration and status registers) in a proprietary FPGA.

The interface to these registers are x86 IO-instructions (inb, outb), and 
there is also an Interrupt line (for Watchdog)

Currently, we support this multi-function-FPGA by a proprietary Watchdog 
driver, which contains a lot of proprietary ioctl()'s.
Not nice, i know, but functional, and also other companies do it in similar 
manner.

But we want to keep in track with the current coding conventions; for this 
reason i ask, how you would recommend us to implement such a proprietary 
interface ?

UIO ? 
currently, this doesnt support IO-mapped devices, only memory-mapped !

ioperm() or iopl() to gain access to IO's from user space ?
Would be the most pragmatic approach, but how would i handle the interrupt 
then ?

Staying with our multi-purpose driver ?
Works well, and also for OSADL-certification it is - as far as i understand 
this - allowed to have Kernel drivers, which are not upstream-capable.

Or building a bundle of single-purpose drivers, one for LEDs, one for 
Watchdog, and so on ?
Would work, but seems to be too overloaded for this simple functionality.

What would you recommend ?

-- 
Mit freundlichen Gruessen / Best regards

Claus Gindhart
SW R&D
Kontron Modular Computers
phone :++49 (0)8341-803-374
mailto:claus.gindhart at kontron-modular.com
http://www.kontron.com