Date: Sun, 23 Jan 2000 23:56:36 +0100 From: "Joachim Jäckel" <Joachim.Jaeckel@d.kamp.net> To: asmodai@wxs.nl, nox@jelal.kn-bremen.de, "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org> Subject: Re: How to write a device-driver? Message-ID: <388B8724.D3B9707C@d.kamp.net>
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Hello again,
thanks for your answers, last week, I was really busy to work, gather
information for the card, inspect the existing drivers and so on...
Here´s some information to the card I'd like to support:
It's a Miro DC10+ Video Grabber Card for Non-Linear Video-Editing.
It uses a Siemens SAA7110, a Zoran 36060+36067 and a ADV???? chip to en-
and decode the video-information. I got the specifications for the chips
from Siemens and Zoran's Web-Sites and a first driver-skeleton was
generated through the /usr/share/examples/drivers/make_pci... script for
me. Currently I get a boot-message from my kernel, that he has found the
card.(I read the pci_id and send a text-message :-)
Additionally I found a linux-driver for this card (an early one...) but
it is not fully compatible with the documentation, I got.
The chip-documentation is a little bit hard to read for someone who is
used to program commercial-applications. (and another thing at the
moment is to understand, what is needed in the driver to communicate
with these chips...)
But I'm working on it...
(I think that I could get it running one day...)
Currently I'm reading the sources of the bktr- and meteor-device to
examine the equals etc.
Maybe you would allow me one question? (To get a little faster to the
information than browsing through the source.)
The card uses several registers in the "front-end" chip, the zoran
36067, which are described in the documentation. I found the pci_map_mem
function, where I've to pass a virtual and a base address to the
function which are usually defined in the softc structure.
My softc structure should therefore look something like this:
typedef struct mdcten_softc {
struct zoran36067_regs *base; vm_offset_t phys_base; ...
and the zoran36067_regs like:
struct zoran36067_regs {
u_int rega; u_int regb; etc.
But how get's the zoran36067_regs structure the information from the
chip?
If I change the content of the structure, which function would change
the registers on the chip accordingly? (Or is it done through the call
of pci_map_mem? And is everything I change to the structure
automatically changed on the card?)
It would be nice if you would answer my question, to make it a little
bit easier for me.
Sorry, if these questions are real dumb ones!
Thanks in advance.
--
Joachim.Jaeckel@d.kamp.net -- http://home.kamp.net/home/joachim.jaeckel
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