From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [RFC PATCH 3/7] iommu/arm-smmu-v3: Introduce smmu option USE_SHARED_IRQS for Silicon errata Date: Tue, 11 Apr 2017 17:21:24 +0100 Message-ID: <20170411162123.GF17109@arm.com> References: <1491921765-29475-1-git-send-email-linucherian@gmail.com> <1491921765-29475-4-git-send-email-linucherian@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from foss.arm.com ([217.140.101.70]:35604 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753078AbdDKQVE (ORCPT ); Tue, 11 Apr 2017 12:21:04 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Robin Murphy Cc: linucherian@gmail.com, catalin.marinas@arm.com, lorenzo.pieralisi@arm.com, hanjun.guo@linaro.org, sudeep.holla@arm.com, rjw@rjwysocki.net, lenb@kernel.org, joro@8bytes.org, robert.moore@intel.com, lv.zheng@intel.com, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, iommu@lists.linux-foundation.org, devel@acpica.org, Sunil.Goutham@cavium.com, Geethasowjanya.Akula@cavium.com, robert.richter@cavium.com, linu.cherian@cavium.com, Geetha On Tue, Apr 11, 2017 at 04:54:26PM +0100, Robin Murphy wrote: > On 11/04/17 15:42, linucherian@gmail.com wrote: > > From: Geetha > > > > Cavium 99xx SMMU implementation doesn't not support unique irq lines for > > gerror, eventq and cmdq-sync. USE_SHARED_IRQS option enables to use single > > irq line for all three interrupts. > > AFAICS, there's nothing actually wrong with using shared wired IRQs - > the architecture spec doesn't appear to say anything about it. I think > it might suffice to simply add IRQF_SHARED if we can see the SMMU > doesn't support MSIs anyway - it doesn't really seem like something we > need to treat as a specific quirk. No, this is not permitted by the spec. See 3.18.2 ("Interrupt sources"), where it's clear that each source asserts a *unique* wired interrupt. Geetha: does your implementation support MSIs? Will From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Tue, 11 Apr 2017 17:21:24 +0100 Subject: [RFC PATCH 3/7] iommu/arm-smmu-v3: Introduce smmu option USE_SHARED_IRQS for Silicon errata In-Reply-To: References: <1491921765-29475-1-git-send-email-linucherian@gmail.com> <1491921765-29475-4-git-send-email-linucherian@gmail.com> Message-ID: <20170411162123.GF17109@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Apr 11, 2017 at 04:54:26PM +0100, Robin Murphy wrote: > On 11/04/17 15:42, linucherian at gmail.com wrote: > > From: Geetha > > > > Cavium 99xx SMMU implementation doesn't not support unique irq lines for > > gerror, eventq and cmdq-sync. USE_SHARED_IRQS option enables to use single > > irq line for all three interrupts. > > AFAICS, there's nothing actually wrong with using shared wired IRQs - > the architecture spec doesn't appear to say anything about it. I think > it might suffice to simply add IRQF_SHARED if we can see the SMMU > doesn't support MSIs anyway - it doesn't really seem like something we > need to treat as a specific quirk. No, this is not permitted by the spec. See 3.18.2 ("Interrupt sources"), where it's clear that each source asserts a *unique* wired interrupt. Geetha: does your implementation support MSIs? Will