From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753850AbbAGQF0 (ORCPT ); Wed, 7 Jan 2015 11:05:26 -0500 Received: from mho-02-ewr.mailhop.org ([204.13.248.72]:35624 "EHLO mho-02-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753199AbbAGQFW (ORCPT ); Wed, 7 Jan 2015 11:05:22 -0500 X-Mail-Handler: Dyn Standard SMTP by Dyn X-Originating-IP: 96.249.243.124 X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/sendlabs/outbound_abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX19dIeVcc9EqJn7M/aZ/oMkrDn9W2YXvzx0= X-DKIM: OpenDKIM Filter v2.0.1 titan 474C463FC22 Date: Wed, 7 Jan 2015 11:05:02 -0500 From: Jason Cooper To: Marc Zyngier Cc: Bjorn Andersson , Abhijeet Dharmapurikar , Stephen Boyd , Phong Vo , Linus Walleij , Tin Huynh , Y Vo , Thomas Gleixner , Toan Le , Arnd Bergmann , linux-arm-msm , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v2 1/3] genirq: Allow the irqchip state of an IRQ to be save/restored Message-ID: <20150107160502.GJ24989@titan.lakedaemon.net> References: <1417623503-30261-1-git-send-email-marc.zyngier@arm.com> <1417623503-30261-2-git-send-email-marc.zyngier@arm.com> <5486C2D6.6020006@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5486C2D6.6020006@arm.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Marc, On Tue, Dec 09, 2014 at 09:37:26AM +0000, Marc Zyngier wrote: > On 08/12/14 22:42, Bjorn Andersson wrote: > > On Wed, Dec 3, 2014 at 8:18 AM, Marc Zyngier wrote: > >> There is a number of cases where a kernel subsystem may want to > >> introspect the state of an interrupt at the irqchip level: > >> > >> - When a peripheral is shared between virtual machines, > >> its interrupt state becomes part of the guest's state, > >> and must be switched accordingly. KVM on arm/arm64 requires > >> this for its guest-visible timer > >> - Some GPIO controllers seem to require peeking into the > >> interrupt controller they are connected to to report > >> their internal state > >> > >> This seem to be a pattern that is common enough for the core code > >> to try and support this without too many horrible hacks. Introduce > >> a pair of accessors (irq_get_irqchip_state/irq_set_irqchip_state) > >> to retrieve the bits that can be of interest to another subsystem: > >> pending, active, and masked. > >> > >> - irq_get_irqchip_state returns the state of the interrupt according > >> to a parameter set to IRQCHIP_STATE_PENDING, IRQCHIP_STATE_ACTIVE, > >> IRQCHIP_STATE_MASKED or IRQCHIP_STATE_LINE_LEVEL. > >> - irq_set_irqchip_state similarly sets the state of the interrupt. > >> > >> Signed-off-by: Marc Zyngier > > > > With the addition of actually assigning err to something useful in the > > setter below: > > > > Reviewed-by: Bjorn Andersson > > Tested-by: Bjorn Andersson > > > >> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c > > > > [..] > > > >> +/** > >> + * irq_set_irqchip_state - set the state of a forwarded interrupt. > >> + * @irq: Interrupt line that is forwarded to a VM > >> + * @which: State to be restored (one of IRQCHIP_STATE_*) > >> + * @val: Value corresponding to @which > >> + * > >> + * This call sets the internal irqchip state of an interrupt, > >> + * depending on the value of @which. > >> + * > >> + * This function should be called with preemption disabled if the > >> + * interrupt controller has per-cpu registers. > >> + */ > >> +int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which, > >> + bool val) > >> +{ > >> + struct irq_desc *desc; > >> + struct irq_data *data; > >> + struct irq_chip *chip; > >> + unsigned long flags; > >> + int err = -EINVAL; > >> + > >> + desc = irq_get_desc_buslock(irq, &flags, 0); > >> + if (!desc) > >> + return err; > >> + > >> + data = irq_desc_get_irq_data(desc); > >> + > >> + do { > >> + chip = irq_data_get_irq_chip(data); > >> + if (chip->irq_set_irqchip_state) > >> + break; > >> +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY > >> + data = data->parent_data; > >> +#else > >> + data = NULL; > >> +#endif > >> + } while (data); > >> + > >> + if (data) > >> + chip->irq_set_irqchip_state(data, which, val); > > > > err = > > Ah, that will teach me to write test code that actually checks the > return value! :-) > > Thanks for the fix and the tags. Did I miss the new version of this? thx, Jason.