From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <43DDE344.1000900@domain.hid> Date: Mon, 30 Jan 2006 10:58:28 +0100 From: Philippe Gerum MIME-Version: 1.0 Subject: Re: [Xenomai-core] Missing IRQ end function on PowerPC References: <200601300833.k0U8XtG31144@domain.hid> <43DDDA6A.3080907@domain.hid> In-Reply-To: <43DDDA6A.3080907@domain.hid> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: xenomai@xenomai.org Jan Kiszka wrote: > Wolfgang Grandegger wrote: > >>>This is an OpenPGP/MIME signed message (RFC 2440 and 3156) >>> >>>Philippe Gerum wrote: >>> >>>>Gilles Chanteperdrix wrote: >>>> >>>>>Wolfgang Grandegger wrote: >>>>> > Therefore we need a dedicated function to re-enable interrupts in >>>>>the > ISR. We could name it *_end_irq, but maybe *_enable_isr_irq is >>>>>more > obvious. On non-PPC archs it would translate to *_irq_enable. >>>>>I > realized, that *_irq_enable is used in various place/skins and >>>>>therefore > I have not yet provided a patch. >>>>> >>>>>The function xnarch_irq_enable seems to be called in only two >> >>functions, >> >>>>>xintr_enable and xnintr_irq_handler when the flag XN_ISR_ENABLE is set. >>>>> >>>>>In any case, since I am not sure if this has to be done at the Adeos >>>>>level or in Xenomai, we will wait for Philippe to come back and decide. >>>>> >>>> >>>>->enable() and ->end() all mixed up illustrates a silly x86 bias I once >>>>had. We do need to differentiate the mere enabling from the IRQ epilogue >>>>at PIC level since Linux does it - i.e. we don't want to change the >>>>semantics here. >>>> >>>>I would go for adding xnarch_end_irq -> rthal_irq_end to stick with the >>>>Linux naming scheme, and have the proper epilogue done from there on a >>>>per-arch basis. >>>> >>>>Current uses of xnarch_enable_irq() should be reserved to the >>>>non-epilogue case, like xnintr_enable() i.e. forcibly unmasking the IRQ >>>>source at PIC level outside of any ISR context for such interrupt (*). >>>>XN_ISR_ENABLE would trigger a call to xnarch_end_irq, instead of >>>>xnarch_enable_irq. I see no reason for this fix to leak to the Adeos >>>>layer, since the HAL already controls the way interrupts are ended >>>>actually; it just does it improperly on some platforms. >>>> >>>>(*) Jan, does rtdm_irq_enable() have the same meaning, or is it intended >>>>to be used from the ISR too in order to revalidate the source at PIC >> >>level? >> >>>Nope, rtdm_irq_enable() was never intended to re-enable an IRQ line >>>after an interrupt, and the documentation does not suggest this either. >>>I see no problem here. >> >>But RTDM needs a rtdm_irq_end() functions as well in case the >>user wants to reenable the interrupt outside the ISR, I think. > > > If this is a valid use-case, it should be really straightforward to add > this abstraction to RTDM. We should just document that rtdm_irq_end() > shall not be invoked from IRQ context - It's the other way around: ->end() would indeed be called from the ISR epilogue, and ->enable() would not. to avoid breaking the chain in > the shared-IRQ scenario. RTDM_IRQ_ENABLE must remain the way to > re-enable the line from the handler. > > Jan > > -- Philippe.