[Xenomai-help] rt_io_get_region

[Xenomai-help] rt_io_get_region

[Roger Carns]

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  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.
-- 

*Roger Carns*

TSS Engineering
321-722-0082 x222 (w)

rpcarns@domain.hid
_www.tssleft.com <http://www.tssleft.com/>_ _We Move Projects Left. You 
Feel Better.


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Re: [Xenomai-help] rt_io_get_region

[Gilles Chanteperdrix]

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.

Re: [Xenomai-help] rt_io_get_region

[Gilles Chanteperdrix]

Roger Carns wrote:
> 
> On 10/11/2010 3:18 PM, Gilles Chanteperdrix wrote:
>> 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.
>> 
> So, I open the /dev/mem and use the fd returned on the mmap call. But
> how do I associate the region defined in the rt_io_get_region with
> that fd?

The offset passed to mmap is the physical address which you want to map.

Please do not forget to CC the maling list.

-- 
                                                                Gilles.

Re: [Xenomai-help] rt_io_get_region

[Roger Carns]

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On 10/11/2010 3:32 PM, Gilles Chanteperdrix wrote:
> Roger Carns wrote:
>> On 10/11/2010 3:18 PM, Gilles Chanteperdrix wrote:
>>> 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.
>>>
>> So, I open the /dev/mem and use the fd returned on the mmap call. But
>> how do I associate the region defined in the rt_io_get_region with
>> that fd?
> The offset passed to mmap is the physical address which you want to map.
>
> Please do not forget to CC the maling list.
>
> great that was what I was going try first...thanks for your help

-- 

*Roger Carns*

TSS Engineering
321-722-0082 x222 (w)

rpcarns@domain.hid
_www.tssleft.com <http://www.tssleft.com/>_ _We Move Projects Left. You 
Feel Better.


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