[Xenomai-help] how to use rt_io_get_region function on AT91SAM9263 in user space

[Xenomai-help] how to use rt_io_get_region function on AT91SAM9263 in user space

[yi zheng]

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   Hi,all
     I want to write a Xenomai application running in user space that can
access the
GPIO pins of my AT91SAM9263 ARM. To get the memory
region I found the function rt_misc_get_io_region(). Unfortunately
there is no discription of this function in the API documentation.
Does this function work like request_mem_region()?
Anybody knows how to use it,please tell me. It is best if there is a little
example.IF there is another way to access memory for user space application
on arm， please let me  know.Thank you.
regards
yizheng

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Re: [Xenomai-help] how to use rt_io_get_region function on AT91SAM9263 in user space

[Gilles Chanteperdrix]

On 08/29/2011 09:43 AM, yi zheng wrote:
>    Hi,all
>      I want to write a Xenomai application running in user space that can
> access the
> GPIO pins of my AT91SAM9263 ARM. To get the memory
> region I found the function rt_misc_get_io_region(). Unfortunately
> there is no discription of this function in the API documentation.
> Does this function work like request_mem_region()?

Yes, it allows user-space access to request_mem_region. So, in addition
to this, you should do the usual mmap(/dev/mem) dance. However, it is
probably better to write an RTDM driver using linux gpiolib. This way,
you get mutual exclusion between linux and xenomai.

-- 
                                                                Gilles.

Re: [Xenomai-help] how to use rt_io_get_region function on AT91SAM9263 in user space

[yi zheng]

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>
> >>    Hi,all
> >>      I want to write a Xenomai application running in user space that
> can
> >> access the
> >> GPIO pins of my AT91SAM9263 ARM. To get the memory
> >> region I found the function rt_misc_get_io_region(). Unfortunately
> >> there is no discription of this function in the API documentation.
> >> Does this function work like request_mem_region()?
>
> >Yes, it allows user-space access to request_mem_region. So, in addition
> >to this, you should do the usual mmap(/dev/mem) dance. However, it is
> >you get mutual exclusion between>probably better to write an RTDM driver
> using linux gpiolib. This way,

> linux and xenomai.

   Do you mean I just access io memory like standard linux with following
steps:
   fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1);
    map_base = mmap((void *)target, nSize, PROT_READ | PROT_WRITE,
MAP_SHARED,fd, target)
   or there is something wrong with my understanding.If this is not the
correct way please give me a simple example，thank you.

> >--
> >                                                               Gilles.
>
 regards
 yizheng

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Re: [Xenomai-help] how to use rt_io_get_region function on AT91SAM9263 in user space

[Gilles Chanteperdrix]

On 08/29/2011 02:09 PM, yi zheng wrote:
>>
>>>>    Hi,all
>>>>      I want to write a Xenomai application running in user space that
>> can
>>>> access the
>>>> GPIO pins of my AT91SAM9263 ARM. To get the memory
>>>> region I found the function rt_misc_get_io_region(). Unfortunately
>>>> there is no discription of this function in the API documentation.
>>>> Does this function work like request_mem_region()?
>>
>>> Yes, it allows user-space access to request_mem_region. So, in addition
>>> to this, you should do the usual mmap(/dev/mem) dance. However, it is
>>> you get mutual exclusion between>probably better to write an RTDM driver
>> using linux gpiolib. This way,
> 
>> linux and xenomai.
> 
>    Do you mean I just access io memory like standard linux with following
> steps:
>    fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1);
>     map_base = mmap((void *)target, nSize, PROT_READ | PROT_WRITE,
> MAP_SHARED,fd, target)
>    or there is something wrong with my understanding.If this is not the
> correct way please give me a simple example，thank you.

For an example of /dev/mem usage, see devmem2.c sources. For instance here:
http://www.mail-archive.com/busybox@domain.hid

We do not have an example of rt_misc_get_io_region() available.

-- 
					    Gilles.