From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751194AbaLPOUw (ORCPT ); Tue, 16 Dec 2014 09:20:52 -0500 Received: from down.free-electrons.com ([37.187.137.238]:35178 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751084AbaLPOUr (ORCPT ); Tue, 16 Dec 2014 09:20:47 -0500 Date: Tue, 16 Dec 2014 15:20:41 +0100 From: Boris Brezillon To: Thomas Gleixner Cc: "Rafael J. Wysocki" , "Rafael J. Wysocki" , Greg Kroah-Hartman , Jiri Slaby , linux-serial@vger.kernel.org, Alessandro Zummo , rtc-linux@googlegroups.com, Mike Turquette , Nicolas Ferre , Jean-Christophe Plagniol-Villard , Alexandre Belloni , Andrew Victor , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/5] ARM: at91: fix irq_pm_install_action WARNING Message-ID: <20141216152041.56ff9b2e@bbrezillon> In-Reply-To: References: <1418660152-17185-1-git-send-email-boris.brezillon@free-electrons.com> <2662748.NJbkr6jW7r@vostro.rjw.lan> <3542278.8lcJeXLMFm@vostro.rjw.lan> <20141216100715.57baeb65@bbrezillon> <20141216122503.77c5632f@bbrezillon> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.23; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 16 Dec 2014 13:56:26 +0100 (CET) Thomas Gleixner wrote: > On Tue, 16 Dec 2014, Boris Brezillon wrote: > > Thomas Gleixner wrote: > > > Install the timer interrupt as a demultiplexing interrupt. > > > > I can try to hack the AIC irqchip driver to implement this demux logic, > > but this logic can't be placed in the PIT (Periodic Interval Timer) > > driver itself, because the shared IRQ line is used by the at91 clock > > controller (PMC) which is providing the clock to the PIT device. > > This gives the following dependency graph: > > > > PIT =depends-on=> Master Clock =provided-by=> PMC =needs=> PMC IRQ. > > It never can be a part of a device driver. This is a property of the > interrupt controller which fails to provide a proper demux for this > irq line in the first place. > > So you fake the demux in the irq chip driver, where you provide the > pseudo chip and the demux logic. None of the device drivers (PIT, PMC, > UART ...) even knows about that. > > |--------| |--------| > | AIC |-------------| Pseudo |---- PIT > | | | chip |---- PMC > | | | |---- UART > | | |--------| > | |--- devX > | |--- devY > | |--- devZ > |--------| > > So PIT, PMC and UART get interrupt numbers handed out which are > outside of the interrupt space of AIC. Okay, that's what I had in mind, thanks for clarifying this aspect. Regarding the DT representation, it should look like this, right ? aic: interrupt-controller@fffff000 { #interrupt-cells = <3>; compatible = "atmel,at91rm9200-aic"; interrupt-controller; reg = <0xfffff000 0x200>; atmel,external-irqs = <29 30 31>; irq1_demux: irq1-demux { #interrupt-cells = <1>; interrupt-controller; } }; pit: timer@fffffd30 { compatible = "atmel,at91sam9260-pit"; reg = <0xfffffd30 0xf>; /* 0 is the id reserved for the PIT */ interrupts-extended = <&irq1_demux 0>; clocks = <&mck>; }; pmc: pmc@fffffc00 { compatible = "atmel,at91sam9260-pmc"; reg = <0xfffffc00 0x100>; /* 1 is the id reserved for the PMC */ interrupts-extended = <&irq1_demux 1>; [...] }; Regards, Boris -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com