From: "M. Koehrer" <mathias_koehrer@domain.hid>
To: kalibera@domain.hid, xenomai@xenomai.org
Subject: Re: [Xenomai-help] Direct access to I/O ports and physical memory from user-space
Date: Wed, 26 Mar 2008 11:36:40 +0100 (CET) [thread overview]
Message-ID: <12369029.1206527800712.JavaMail.ngmail@domain.hid> (raw)
In-Reply-To: <47E9B406.8030407@domain.hid>
Hello Tomas,
outb() and inb() are actually realized by the correspondend x86 CPU commands
(Please see the Intel/AMD references for details).
Thus, there is no mode switch as this not a system call.
The same is with memory mapped IO. I use this regularly to access (proprietary) PCI hardware
directly from user space. This works perfectly.
Regards
Mathias
> Hello,
>
> is it possible to access I/O port on x86 solely from Xenomai user-space
> primary domain ? I assume that iopl() and then outb(), inb() should
> work. But, how to avoid switches to secondary domain ?
>
> Similarly, for physical memory, there is an example in Xenomai
> distribution that mmaps /dev/mem. Is there a way to avoid switches here ?
>
> Thanks,
> Tomas
>
>
> _______________________________________________
> Xenomai-help mailing list
> Xenomai-help@domain.hid
> https://mail.gna.org/listinfo/xenomai-help
>
--
Mathias Koehrer
mathias_koehrer@domain.hid
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prev parent reply other threads:[~2008-03-26 10:36 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-26 2:25 [Xenomai-help] Direct access to I/O ports and physical memory from user-space Tomas Kalibera
2008-03-26 10:36 ` M. Koehrer [this message]
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