Date: Sun, 13 Oct 1996 13:47:15 -0700 (MST) From: Richard Straka <straka@inficad.com> To: questions@FreeBSD.ORG Subject: Registering ISR for LKM Device Driver Message-ID: <Pine.BSI.3.91.961013132349.1989A-100000@inficad.com>
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I am in the process of writing several device drivers for FreeBSD to
interact with custom realtime test equipment. This hardware is interrupt
driven and hence, I have to register the interrupt service routines with
the kernel. It is highly desirable to use the Loadable Module mechanism
for inclusion of the device drivers into the kernel. I have the following
questions.
- Where can I get a template of an LKM device driver that uses
interrupts?
- What is the relationship between register_intr(), register_imask(),
and update_intr_masks() in /sys/i386/isa/isa.c? Can I use these
calls in some sequence to register my LKM ISR's? Looking at the
code, some of the functionality of these 3 routines look redundant.
- How do I unregister the interrupts and clean up the interrupt masks
when I unload the module. Does the function unregister_intr() from
isa.c take care of this for me?
- What is the distinction between a fast and slow interrupt? Some of
the interrupts from my test equipment may be rather high frequency
>1000HZ and require low latency. Do I need to take additional
precautions in my drivers if I use fast interrupts?
Any help on these issues would be greatly appreciated.
Thanks in advance.
Richard Straka
straka@inficad.com
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