From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <51E7FA79.6030602@163.com> Date: Thu, 18 Jul 2013 22:23:53 +0800 From: aking MIME-Version: 1.0 References: <51E4F63A.7080203@163.com> <51E55AB0.8070600@siemens.com> In-Reply-To: <51E55AB0.8070600@siemens.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai] general kernel functions in RTDM? List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: "xenomai@xenomai.org" 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 -- Best Regards aking_jin