Re: Should I use Linux to develop driver for specialized ISA card?

[Erik Mouw]

On Tue, Sep 04, 2001 at 02:57:10PM +0200, Rastislav Stanik wrote:
> I'm developing specialized plotter.
> The moving parts of the plotter are controlled by ISA card that generates
> (and responds to) interrupts on each movement or printing event.
> The interrupts can be generated quite fast; up to frequency of 4kHz.

I just made a driver for a couple of serial A/Ds that runs at 2kHz on a
StrongARM platform. The system doesn't have any problems to keep up
with that frequency, so I think 4kHz would still be OK.

> I need to write a driver for that.
> The 1st prototype is developed in MS-DOS,but I hit problem with memory.
> The driver needs to use (and transfer) quite big chunks of memory.
> 1MB is not enough.
> 
> In NT you don't develop drivers so easily. It is actually a pain.
> Therefore I'm considering Linux. The machine would be probably 
> dedicated and, may be later, embeded in the plotter.
> Problems:
> - It is unlikely that my driver would ever make it to main-stream
>   kernel source.

That's no problem, most of the embedded drivers never do.

> - I'm just a C/C++ programmer, I have just rough idea what does it
> mean to 'develop a driver in Linux'. I'm pretty familiar with Linux
> as sys-admin though.

Forget about C++ for kernel programming, it simply doesn't work (see
the lkml FAQ at http://www.tux.org/lkml/ ). A nice starting point for
kernel programming is http://www.kernelnewbies.org/ together with its
IRC channel #kernelnewbies. Also get a copy of the book "Linux device
drivers (2nd edition)", there is a link in the books section on the
kernelnewbies website.

> All I need is: to have piece of code executed on some interrupt,
> read/write IO ports of the card and be able to transfer big pieces
> of memory to the card.
> 
> What do you think? Is Linux the ideal platform for me?

I don't know if Linux is the *ideal* platform, but driving a plotter
could certainly be done in Linux.

Erik

-- 
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031,  2600 GA Delft, The Netherlands
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