From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lokesh Vutla Subject: Re: [PATCH v5 05/10] dt-bindings: irqchip: Introduce TISCI Interrupt router bindings Date: Sat, 16 Feb 2019 08:59:55 +0530 Message-ID: <2369739e-3bc8-257a-99e0-db2951c6777d@ti.com> References: <20190212074237.2875-1-lokeshvutla@ti.com> <20190212074237.2875-6-lokeshvutla@ti.com> <20190212162247.GK5720@atomide.com> <6a274588-0fb6-2ddf-3bcc-f9e4d849ac07@ti.com> <20190213152620.GS5720@atomide.com> <4791de04-63af-4c5e-db9c-47634fcb8dc9@ti.com> <20190214154100.GB5720@atomide.com> <20190214174612.GF5720@atomide.com> <171e8597-2156-747d-d024-7b4bfc6f9186@ti.com> <20190215161629.GK5720@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190215161629.GK5720@atomide.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Tony Lindgren Cc: Nishanth Menon , Device Tree Mailing List , jason@lakedaemon.net, Peter Ujfalusi , marc.zyngier@arm.com, 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 Tony, On 2/15/2019 9:46 PM, Tony Lindgren wrote: > Hi, > > * Lokesh Vutla [190214 18:03]: >> On 2/14/2019 11:16 PM, Tony Lindgren wrote: >>> But I'd rather have a proper hardware based phandle + index >>> type mapping in the dts if possible though. >> >> The idea about sysfw here is that Linux is not aware of anything about >> this device(Interrupt Router). It cannot even access any of its >> registers. As a user Linux should know who is the parent to which the >> Interrut router output should be configured. Then query sysfw about the >> range of gic irqs allocated to it. Now for configuration, Linux should >> pass the the input to interrupt router, gic irq no, and gic id(by which >> sysfw uniquely identifies GIC interrupt controller with the SoC). Based >> on these parameters Interrupt Router registers gets configured. > > If the interrupt router hardawre is hidden away from Linux, > just leave it out of the device tree completely and have the > interrupt controller driver request the routing. Yes while requesting you should at-least specify which is your destination interrupt-controller Else how does the sysfw even know to whom the requester wants the routing to happen to. You do know that we are dealing with a heterogeneous system where there are more the one destination interrupt controllers(GIC, R5 VIM etc etc..). This is what the DT property is specifying and we cannot query a device based on a name. > > The dts node for the interrupt controller should describe a > proper Linux device, that is with reg entries and so on. You are asking to just keep the compatible property :) I am no where denying that. But the cases where the firmware does the configuration DT spec[1] clearly mentions about the interface. Please take a look at arm-psci devicetree binding documentation where the function ids are represented using which each psci function is invoked. [1] https://github.com/devicetree-org/devicetree-specification/releases/download/v0.2/devicetree-specification-v0.2.pdf Thanks and regards, Lokesh