From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757292Ab2INOad (ORCPT ); Fri, 14 Sep 2012 10:30:33 -0400 Received: from smtp.ctxuk.citrix.com ([62.200.22.115]:48949 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754188Ab2INOaa (ORCPT ); Fri, 14 Sep 2012 10:30:30 -0400 X-IronPort-AV: E=Sophos;i="4.80,423,1344211200"; d="scan'208";a="14549106" Date: Fri, 14 Sep 2012 15:28:18 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Marc Zyngier CC: Stefano Stabellini , "arnd@arndb.de" , "xen-devel@lists.xensource.com" , "linaro-dev@lists.linaro.org" , Ian Campbell , "konrad.wilk@oracle.com" , Catalin Marinas , "Tim (Xen.org)" , "linux-kernel@vger.kernel.org" , "linux@arm.linux.org.uk" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v4 16/24] xen: clear IRQ_NOAUTOEN and IRQ_NOREQUEST In-Reply-To: <50533D46.5000704@arm.com> Message-ID: References: <1347621207-11294-16-git-send-email-stefano.stabellini@eu.citrix.com> <505338E6.4050504@arm.com> <50533D46.5000704@arm.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 14 Sep 2012, Marc Zyngier wrote: > On 14/09/12 15:13, Stefano Stabellini wrote: > > On Fri, 14 Sep 2012, Marc Zyngier wrote: > >> On 14/09/12 12:13, Stefano Stabellini wrote: > >>> Reset the IRQ_NOAUTOEN and IRQ_NOREQUEST flags that are enabled by > >>> default on ARM. If IRQ_NOAUTOEN is set, __setup_irq doesn't call > >>> irq_startup, that is responsible for calling irq_unmask at startup time. > >>> As a result event channels remain masked. > >>> > >>> Signed-off-by: Stefano Stabellini > >>> Acked-by: Konrad Rzeszutek Wilk > >>> --- > >>> drivers/xen/events.c | 1 + > >>> 1 files changed, 1 insertions(+), 0 deletions(-) > >>> > >>> diff --git a/drivers/xen/events.c b/drivers/xen/events.c > >>> index 5ecb596..8ffb7b7 100644 > >>> --- a/drivers/xen/events.c > >>> +++ b/drivers/xen/events.c > >>> @@ -836,6 +836,7 @@ int bind_evtchn_to_irq(unsigned int evtchn) > >>> struct irq_info *info = info_for_irq(irq); > >>> WARN_ON(info == NULL || info->type != IRQT_EVTCHN); > >>> } > >>> + irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN); > >> > >> This one just sent a shiver down my spine. Are you doing this for a PPI? > > > > Not really: even though there is just one source of event notifications > > (that is a PPI), we have many event channels. When a domain receives a > > notification (via the PPI), it checks on a bitmask to which event channel > > it corresponds. From the Linux point of view every event channel is a > > Linux irq belonging to the xen_dynamic_chip (see > > drivers/xen/events.c:xen_dynamic_chip). > > > > So here I am not doing this for the one PPI, but I am doing this for > > every Linux irq (of chip xen_dynamic_chip) that represents an event > > channel. > > So this is some sort of secondary interrupt controller, cascaded into > your GIC emulation, I guess it could be seen as a secondary interrupt controller > and this patch only affects the xen_dynamic_chip? Yep