Driver development question

[Christopher J. Harrer]

> -----Original Message-----
> From: owner-freebsd-drivers at freebsd.org [mailto:owner-freebsd-
> drivers at freebsd.org] On Behalf Of Marc Loerner
> Sent: Tuesday, July 21, 2009 2:34 AM
> To: freebsd-drivers at freebsd.org
> Subject: Re: Driver development question
> 
> Am Dienstag 21 Juli 2009 00:38:56 schrieb Sam Leffler:
> > John Baldwin wrote:
> > > On Friday 17 July 2009 11:10:17 am Chris Harrer wrote:
> > >> Hi All,
> > >>
> > >> I'm hoping someone can point me in the right direction...  I'm
> > >> developing a FreeBSD driver for a PCIe card.  The driver controls
> a
> > >> hardware device that has DRAM and various state information on it.
> I'm
> > >> trying to mimic functionality I have for other OS support such
> that I
> > >> can dump memory and state information from the card to a file I
> create
> > >> from within my driver (kernel module).
> > >>
> > >> For example, in a Linux driver I use filp_open to create the dump
> file
> > >> (represented by fp), then use fp->f_op->write to put information
> into
> > >> the file.
> > >>
> > >> FreeBSD doesn't have filp_* API's.  I've tried searching for
> example
> > >> drivers and googling for file API's from kernel modules to no
> avail.
> > >> Can someone please offer some guidance as to how I might proceed
> here?
> > >>
> > >> Thanks in advance and any insight would be most appreciated!
> > >
> > > You can look at sys/kern/kern_ktrace.c to see how the ktrace()
> system
> > > call creates a file.  I think in general you will wind up using
> > > NDINIT/namei() (to lookup the vnode for a pathname) and then
> vn_open() /
> > > vn_rdwr() / vn_close().
> >
> > man alq(9).
> >
> >
> 
> Why not use kern_open, kern_close, kern_preadv, kern_pwritev?
> 
> Regards,
> Marc

Thanks for the suggestions everyone, I will be investigating more today.  I
appreciate all the pointers!

Cheers,

Chris