Re: [Xenomai] general kernel functions in RTDM?

[aking <jinxin16897123@163.com>]

On 7/19/2013 Friday 7:30 PM, Gilles Chanteperdrix wrote:
> On 07/18/2013 04:23 PM, aking wrote:
>
>> On 7/16/2013 Tuesday 10:37 PM, Jan Kiszka wrote:
>>> On 2013-07-16 09:28, aking_jin wrote:
>>>> Hi,all
>>>> What should be take care of while using general kernel functions in
>>>> RTDM? for example: dma operation, GPIO operation and etc .
>>> Depends on their usage context. You can normally use Linux service 
>>> while
>>> the driver is in Linux context. But once you run over an RT IRQ, RT
>>> timer handler or RT thread (kernel/userspace), most Linux services
>>> become taboo.
>>>
>>> DMA mapping/unmapping, e.g., may still work if it involves no hardware
>>> or software IOMMU, otherwise it is required to premap the regions 
>>> during
>>> setup over a Linux context. GPIO may involve Linux code that
>>> synchronizes against concurrent access. If that code was hardened as
>>> part of the I-pipe patch, you are safe again.
>>>
>>> Hope this helped to get the general picture. Detailed answers depend on
>>> what you do, and on which hardware.
>>>
>>> Jan
>>>
>> How could I toggle gpio in isr of xenomai RTDM?
>> Thanks
>>
>
> No answer, so, you probably did not understand: on what architecture 
> are you using Xenomai? x86? arm? other?
>
> If on ARM, gpio_set_value should allow toggling the GPIO in an RTDM 
> ISR, but you have to pay attention to:
>
> http://www.xenomai.org/index.php/I-pipe-core:ArmPorting#GPIOs_in_real-time_drivers 
>
>
I'm using arm, Xscale architecture.
Thank you Very much.

-- 
Best Regards
aking_jin