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Date: Mon, 11 Oct 2010 21:18:44 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai-help] rt_io_get_region
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To: Roger Carns <rpcarns@domain.hid>
Cc: xenomai@xenomai.org

Roger Carns wrote:
>   Does rt_io_get_region function be called from user space and does it 
> return a user space address and if so how is it return? Also is there 
> doc out there someplace on usage of this function.

rt_io_get_region is a user-space mapping of
request_mem_regio/request_io_region. As such, yes, it may be called from
user-space. And no, it does not return address. What it returns is a
cookie that may be passed to rt_io_put_region to free the used memory.

In order to map an MMIO region in user-space you should use /dev/mem
or use ioperm and inl/outl directly if you want to access an I/O port.
What rt_io_get_region does is to allow you to this cleanly with regard
to the rest of the system.

-- 
                                                                Gilles.