steve rosenbluth wrote:
(...)
> > ------------------------------------------------------------------
> > 6.3.1.3 Files and directories
> >
> > --- RTLinux will have a posixio module to give a basic framework for drivers.
> >
> > "The open function is needed to do basic device I/O, also to provide device
>initialization."
> > "Although this requires some form of name resolution, a full pathname is
>specifically not
> > required. Directories are also not required."
> >
> > open(s,mode) == if(s[1] != 0 ) return -EINVAL; return
>symbolic_name_to_fifo_number(s[0]);
> > ------------------------------------------------------------------
> > 6.3.1.4 Input and output
> >
> > "The functions _read_ _write_ , and _close_ are required to do basic i/O and
>device cleanup."
>
> Are you talking about rt-fifo devices only ? what other devices are
> there in rtl ?
>
> Are you saying that rtl users create devices for their ADC cards, etc
> and access those cards with open(), close(), read(), write(), etc. This
> would be resisted by the average hacker, but is arguably the "right" way
> of writing drivers portable to soft real time, etc.
You mean open(), read(), ... from user space? Nope, the rtl_posixio
module (in beta12) provides those calls for use by RTL threads. That is,
true real time all the way though, with a POSIX device driver interface.
:-)
IMO, it should be made *very* easy to port existing standard Linux
drivers to RTLinux, and it should be possible to compile the ported
drivers into binaries for standard Linux if desired. That's what I'm
currently working on. (Although I have to get a song recorded and mixed
before next weekend, so progress is a bit slow ATM.)
In future versions of the DPI, I'll use a special set of headers in
place of the standard Linux kernel ones, and the drivers should then
compile into RTLinux only drivers, standard Linux drivers, or runtime
context sensitive drivers as desired. (CONFIG_xxx_RT = R/S/C or
something...)
You may want to have a look at the code (early beta) at
http://www.angelfire.com/or/audiality/download.html
Note that the included rtl_posixio module is a modified version, and the
driver won't work with the one from the RTL beta12 or beta13 releases.
(The DPI 0.1.0 version isn't too sexy... After the hack I did this
morning it's a bit nicer, at least from the driver porting POV. I'm now
using only the real Linux file and file_operations, and inode.)
//David
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----
For more information on Real-Time Linux see:
http://www.rtlinux.org/~rtlinux/
