Baslinux mailing list

["Anthony J. Albert" <albert AT polaris.umpi.maine.edu>]

On 23 Feb 2004 at 8:09, Nguyen The Luan wrote:
[SNIP]
>The reason why I want to do that is:
>
>I'm writing lowlevel softwares (work on linux) for my system. 
>My softwares are used to test/control hardware devices (SRAM, FLASH, FPGA,
>LEDs,...).
>I need to write my tasks in the way that they can communicate with users.
>But I can't let my user tasks to access directly to memory map of such hw
>devices.
>So I have to write 2 tasks for each application. One in user space and the
>other in kernel space. User space task get information from users and send
>the information to kernel task, kernel task work on hardware and then send
>results to user task, then user task show result to users.
>The model is rather complicated, and it takes me long time to train my
>programmers.
>So I think that If I can make user space tasks can access to hardware
>(system resources) like kernel task can do,
>then my software model will be simpler (only one task for each application),
>easier to develop, debug, and it can run faster.
>
>I control all of the tasks in my system, so I don't care about some user
>tasks can harm my system.
>Please give me some ideas.
>
>Best regards.
>
>Nguyen.

Dear Nguyen,

It so happens that I was reading through the Linux Parallel Processing 
FAQ this weekend, and I came across something which might help you.

http://yara.ecn.purdue.edu/~pplinux/PPHOWTO/pphowto-3.html

Look at the TTL_PAPERS section of the Parallel Processing FAQ, which 
talks about: 

        "User programs using TTL_PAPERS AFAPI directly access the SPP
         (standard parallel port) hardware port registers under Linux, without
         an OS call for each access."

This may lead you in a direction of solving your problem, giving you 
the direct access you want.  From a brief reading, you may need to 
develop an new library, but that will likely do the job...

Hope this help,
Anthony Albert
===========================================================
Anthony J. Albert                     albert AT umpi.maine.edu
Systems and Software Support Specialist          Postmaster
Computer Services - University of Maine, Presque Isle
        "This is only temporary, unless it works."
                        --- Red Green