Re: looking for open tasks

"Niels Reedijk" <[email protected]> Thu, 1 Mar 2007 14:10:29 +0100
Newsgroups gmane.os.openbeos.kernel.devel
Message-ID <[email protected]>
2007/2/28, jan matejek <matejcik-IaeKGDb/[email protected]>:
>
>
> Niels Reedijk napsal(a):
> > * USB OHCI driver is also still open. Got some more code llingering
> > about, but my issue is that I'm in Spain and my development computer
> > is in Holland.
> >
> > I can give some pointers on how to proceed.
> >
> > Niels
> >
> we liked this one too.
> can you please be more specific about what needs to be done, how big it
> is etc. ?

Well, basically, the task is to write the driver of the OHCI
controller. That is the piece of software between the usb stack, which
communicates with individual drivers and does much of the high level
USB protocol stuff, and the OHCI bus that actually communicates with
the individual devices.

Size of the task:
- Even though the higher level part of the USB protocol is already
implemented by Michael, you will still need to get the bigger picture.
Expect at least two weeks or more to get acquainted with the usb spec,
the code etcetera.
- The ohci spec is quite clear and has a lot of example metacode on
how to implement various subparts of the driver
- The big advantage is that Michael already wrote the UHCI driver, so
you basically have a manual on how the stack interacts with your
driver.
- Especially the OHCI driver of solaris is very well-written and might
prove some insight in how to implement certain parts, even though
you'll be doing different stuff because the interface will have to be
different.

What's already there:
- Initialisation routine
- Code for emulation of the root hub.

On my computer in Holland, which I won't access for four months since
I'm in Spain for the time being, I have the beginnings of transmitting
packets. I remember much of that process and I'd be able to help you
getting started on that.

Now to the crucial question, will you be able to do it? Three people,
eight weeks (by now only seven?), perhaps it can be done, but it all
depends on you level, your skills and the available time. I'm not a
kernel programmer, I haven't actually gotten any education as a
programmer before, so my progress is very slowly. It's good that I'm
persistent, else I would have given up on it before. You might make
it, if you understand kernel programming (which I had to learn). And
don't forget that you need the hardware for it.

The task Waldemar proposed, isochronous streams in USB, is perhaps a
viable alternative, however it will require changing the high level
stack and the low level drivers for UHCI and EHCI, plus learning all
about the USB protocol. You'd have to communicate with Michael Lotz on
this one, you shouldn't get in his way. I'd say the OHCI stack is more
self-contained and probably more rewarding if finished.

Kind regards,

Niels

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