From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Ujfalusi Subject: Re: [PATCH v2 09/10] irqchip: ti-sci-inta: Add support for Interrupt Aggregator driver Date: Thu, 1 Nov 2018 11:14:15 +0200 Message-ID: References: <20181018154017.7112-1-lokeshvutla@ti.com> <20181018154017.7112-10-lokeshvutla@ti.com> <9969f24c-cdb0-1f5c-d0f4-b1c1f587325c@ti.com> <86va5ssrfm.wl-marc.zyngier@arm.com> <63ba5353-8470-b4c1-64a8-a1df5bf48614@ti.com> <86va5myz7t.wl-marc.zyngier@arm.com> <81136b74-4b45-f44b-0168-23d191a4fb5e@ti.com> <49029695-79a0-141b-a9da-9764cb0ed60f@ti.com> <86bm792mv2.wl-marc.zyngier@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <86bm792mv2.wl-marc.zyngier@arm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Marc Zyngier Cc: Lokesh Vutla , Nishanth Menon , Device Tree Mailing List , Grygorii Strashko , jason@lakedaemon.net, Sekhar Nori , linux-kernel@vger.kernel.org, Tero Kristo , Rob Herring , Santosh Shilimkar , tglx@linutronix.de, Linux ARM Mailing List List-Id: devicetree@vger.kernel.org Hi Marc, On 11/1/18 11:00 AM, Marc Zyngier wrote: > On Thu, 01 Nov 2018 07:55:12 +0000, > Peter Ujfalusi wrote: >> >> Lokesh, >> >> On 10/29/18 3:04 PM, Lokesh Vutla wrote: >>>>> With the above information, linux should send a message to >>>>> system-controller using TISCI protocol. After policing the given >>>>> information, system-controller does the following: >>>>> - Attaches the interrupt(INTA input) to the device resource index >>>>> - Muxes the interrupt(INTA input) to corresponding vint(INTA output) >>>>> - Muxes the vint(INTR input) to GIC irq(INTR output). >>>> >>>> Isn't there a 1:1 mapping between *used* INTR inputs and outputs? >>>> Since INTR is a router, there is no real muxing. I assume that the >>>> third point above is just a copy-paste error. >>> >>> Right, my bad. INTR is just a router and no read muxing. >> >> INTR can mux M interrupt inputs to N interrupt outputs. >> One selects which interrupt input is outputted on the given interrupt >> output. >> It is perfectly valid (but not sane) to select the same interrupt input >> to be routed to _all_ interrupt output for example. >> >> Not sure if we are going to use this for anything but 1:1 mapping, but >> might worth keeping in mind... > > It's not obvious how you'd use this "feature". Interrupt replicator, > should one of the output be tied to another part of the system? Or > maybe that's just the result of reusing some generic block... I think the intention is that different virtualized OS would got assigned with different range of NAVSS GIC irqs and there might be a case when more than one virtualized environment need to get a GIC irq for the same virt. Timer interrupts comes to mind first, but there could be other cases when the same virt should trigger on multiple GIC line. - Peter Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki