From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <53FD8FBA.3070403@xenomai.org> Date: Wed, 27 Aug 2014 09:58:50 +0200 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <860f4c66b4b34363a35ca81ac139eaba@CVEX13.valentin-carl.de> In-Reply-To: <860f4c66b4b34363a35ca81ac139eaba@CVEX13.valentin-carl.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai] SPI tx underflow interrupt not available List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Reitinger, Peter" , "xenomai@xenomai.org" On 08/27/2014 09:48 AM, Reitinger, Peter wrote: > On 08/26/2014 04:24 PM, Reitinger, Peter wrote: >> Dear Xenomai people, >> >> >> I am currently trying to write an SPI slave rtdm driver with fifo >> and dma support. I would like to receive an interrupt if there is >> an underflow in the tx fifo. >> >> Therefore I try to request the related hardware interrupt (which is >> irq 125 at my emtrion board which has EDMA and 2 McSPI interfaces >> where I am trying McSPI1). > > Are you sure the irq number is 125? If 125 is a "physical" irq > number, it is almost probably not the number you should pass to > rtdm_irq_request. Have you tried requesting it as a Linux interrupt? > > > >> >> Unfortunately it seems that interrupt 125 is reserved by another >> linux > driver because a list of /proc/irq/125 shows: >> >> root@dimm-am335x:/proc# ls /proc/irq/125 53100000.sham spurious > > Have you tried grepping "sham" in the kernel sources? > > No, I am absolutely unsure if 125 is the right number because I am > relatively new in programming interrupts in the kernel. So I feel I > have to read a lot about interrupts in linux? So I have to combine > original linux kernel function calls and xenomai function calls to > get interrupts working? No, the idea is to test the interrupt with Linux alone first, to avoid any potential bug that Xenomai or more probably the I-pipe patch would add. > Sorry that I have so few experience there... > If you have a quick help in mind even though it is not directly > related to Xenomai, you would help me a lot... :-/ > > Thx, I will try to grep for sham. I am afraid there might be a lot of > hits... I have done it (grepped \bsham\b) and found that omaps have a peripheral named sham which is a crypto device. -- Gilles.