From RTEMS to Linux :-(

[Leon Pollak]

Hello to all.

Last 15 years I was programming explicitly in RTEMS and was (and is) very
pleased with this and does not imagined myself in something else.
And the problem is exactly in this.
I need to write some application (actually rather close to those I wrote in
RTEMS) under Linux.
Although I read some Linux docs, it is difficult for me to find a compatible
programming means, especially such as partition manager - I did not find
nothing similar.

Thanks a lot for the help.
--
Leon.
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[Gedare Bloom]

Linux programs are mainly stuck with the POSIX API to the kernel and
whatever you can find in libraries (libc, etc) -- which are usually
built on top of POSIX. Certain types of low-level operations, such as
allocating physically contiguous memory, is not (to my knowledge)
possible from within a user-land application and is not specified by
POSIX. There are kernel interfaces that provide such operations for
kernel-mode code such as device drivers and kernel modules, but I
don't think there are any user API functions to access them.

I would suggest formulating a set of questions specific to what you
are trying to do, and then ask them on some appropriate Linux mailing
lists (e.g. http://www.linux.org/docs/lists.html and
linux-c-programming). My guess is that most of the functionality you
need is available somewhere in some library, but the trick is how to
find it. If you do need low-level functionality (i.e. hardware
dependent) then you will probably have to write a kernel device
driver. There are also good resources online for how to do this, for
example http://lwn.net/Kernel/LDD3/

-Gedare

[Leon Pollak]

On Tuesday March 23 2010, Gedare Bloom wrote:
> Linux programs are mainly stuck with the POSIX API to the kernel and
> whatever you can find in libraries (libc, etc) -- which are usually
> built on top of POSIX. Certain types of low-level operations, such as
> allocating physically contiguous memory, is not (to my knowledge)
> possible from within a user-land application and is not specified by
> POSIX. There are kernel interfaces that provide such operations for
> kernel-mode code such as device drivers and kernel modules, but I
> don't think there are any user API functions to access them.
>
> I would suggest formulating a set of questions specific to what you
> are trying to do, and then ask them on some appropriate Linux mailing
> lists (e.g. http://www.linux.org/docs/lists.html and
> linux-c-programming). My guess is that most of the functionality you
> need is available somewhere in some library, but the trick is how to
> find it. If you do need low-level functionality (i.e. hardware
> dependent) then you will probably have to write a kernel device
> driver. There are also good resources online for how to do this, for
> example http://lwn.net/Kernel/LDD3/

Thank you, Gedare.

No, I almost do not need to do low level programming (and I understand just
for now how to do it). My user space main program is in processing of data
received from low level driver in several stages.
In RTEMS I should do it simple: create a partition, pull the buffer, give it
to the driver to fill, pass it to the processing task(s) and free it at the
end.
I found POSIX threads (look a bit awkward from RTEMS task point of view, but
still usable), mailboxes and signals (analog of semaphores?). But no traces of
something similar to partitions....
This made me think that I am on the wrong way...

[Joel Sherrill]

A partition is internally just an rtems chain. So you could mimic
this easily enough by just bring the chain code over to Linux. I have
done that myself in the past.

--joel

--
Joel Sherrill, Ph.D. Director of Research& Development
joel.s...@OARcorp.com On-Line Applications Research
Ask me about RTEMS: a free RTOS Huntsville AL 35805
Support Available (256) 722-9985

[Alan Cudmore]

Leon,
Another possibility is to use a higher level library like glib:
http://library.gnome.org/devel/glib/2.22/index.html

Glib is one of the core libraries for the GNOME desktop. It has many
RTOS-like primitives, and it is portable to Linux, windows and OS X.
The only thing I'm not sure about is using it in a non-gui
environment, without a main event loop.

Here is the section that has memory management, lists, queues, trees,
etc:
http://library.gnome.org/devel/glib/2.22/glib-data-types.html

There are other C++ libs out there like QT, and boost that may help.

Alan

[Luis Mollinedo Herrera]

Hello to all,

I'm interested in CAN based applications with CANopen protocol for embedded systems (RTEMS), but I didn't find too much information about it. Could someone help me with this request?

Thanks in advance and sorry for the inconveniences.

Best regards,
Luis Mollinedo.

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[Ian Caddy]

Hi,

We have been interested in a CANOpen stack for some time, but still not
got around to it... ;-)

http://www.canfestival.org/

Seems to have been around for a while and we might have a project coming
up in the next 6 months or so that also requires a CANOpen stack and we
were looking at porting over Can Festival to RTEMS.

regards,

Ian Caddy

--
Ian Caddy
Goanna Technologies Pty Ltd
+61 8 9444 2634