From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Richter Subject: Re: [PATCH v3 1/7] iommu/arm-smmu-v3: Introduce SMMU option PAGE0_REGS_ONLY for ThunderX2 errata #74 Date: Sat, 6 May 2017 01:03:28 +0200 Message-ID: <20170505230328.GN4906@rric.localdomain> References: <1493986091-30521-1-git-send-email-gakula@caviumnetworks.com> <1493986091-30521-2-git-send-email-gakula@caviumnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-wr0-f194.google.com ([209.85.128.194]:34324 "EHLO mail-wr0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750951AbdEEXDd (ORCPT ); Fri, 5 May 2017 19:03:33 -0400 Content-Disposition: inline In-Reply-To: <1493986091-30521-2-git-send-email-gakula@caviumnetworks.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Geetha sowjanya Cc: will.deacon@arm.com, robin.murphy@arm.com, lorenzo.pieralisi@arm.com, hanjun.guo@linaro.org, sudeep.holla@arm.com, iommu@lists.linux-foundation.org, jcm@redhat.com, linux-kernel@vger.kernel.org, robert.richter@cavium.com, catalin.marinas@arm.com, sgoutham@cavium.com, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, geethasowjanya.akula@gmail.com, linu.cherian@cavium.com, Charles.Garcia-Tobin@arm.com, Geetha Sowjanya On 05.05.17 17:38:05, Geetha sowjanya wrote: > From: Linu Cherian > > Cavium ThunderX2 SMMU implementation doesn't support page 1 register space > and PAGE0_REGS_ONLY option will be enabled as an errata workaround. > > This option when turned on, replaces all page 1 offsets used for > EVTQ_PROD/CONS, PRIQ_PROD/CONS register access with page 0 offsets. > > Signed-off-by: Linu Cherian > Signed-off-by: Geetha Sowjanya > --- > .../devicetree/bindings/iommu/arm,smmu-v3.txt | 6 +++ > drivers/iommu/arm-smmu-v3.c | 44 ++++++++++++++++------ > 2 files changed, 38 insertions(+), 12 deletions(-) > @@ -1995,8 +2011,10 @@ static int arm_smmu_init_queues(struct arm_smmu_device *smmu) > if (!(smmu->features & ARM_SMMU_FEAT_PRI)) > return 0; > > - return arm_smmu_init_one_queue(smmu, &smmu->priq.q, ARM_SMMU_PRIQ_PROD, > - ARM_SMMU_PRIQ_CONS, PRIQ_ENT_DWORDS); > + return arm_smmu_init_one_queue(smmu, &smmu->priq.q, > + ARM_SMMU_PRIQ_PROD(smmu), > + ARM_SMMU_PRIQ_CONS(smmu), > + PRIQ_ENT_DWORDS); I would also suggest Robin's idea from the v1 review here. This works if we rework arm_smmu_init_one_queue() to pass addresses instead of offsets. This would make these widespread offset calculations obsolete. -Robert