From: Vivek Gautam <vivek.gautam@codeaurora.org>
To: will.deacon@arm.com, robin.murphy@arm.com, joro@8bytes.org,
iommu@lists.linux-foundation.org
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
tfiga@chromium.org, Vivek Gautam <vivek.gautam@codeaurora.org>
Subject: [PATCH 0/2] iommu/arm: Add support for non-coherent page tables
Date: Thu, 17 Jan 2019 14:57:16 +0530 [thread overview]
Message-ID: <20190117092718.1396-1-vivek.gautam@codeaurora.org> (raw)
As discussed in the Qcom system cache support thread [1], it is
imperative that we enable the support for non-cacheable page tables
for SMMU implementations for which removing snoop latency on walks
by making mappings as non-cacheable, outweighs the cost of cache
maintenance on PTE updates.
This series adds a new SMMU device tree option to let the particular
SMMU configuration setup cacheable or non-cacheable mappings for
page-tables out of box. We set a new quirk for i/o page tables -
IO_PGTABLE_QUIRK_NON_COHERENT, that lets us set different TCR
configurations.
This quirk enables the non-cacheable page tables for all masters
sitting on SMMU. Should this control be available per smmu_domain
as each master may have a different perf requirement?
Enabling this for the entire SMMU may not be desirable for all
masters.
[1] https://lore.kernel.org/patchwork/patch/1020906/
Vivek Gautam (2):
iommu/io-pgtable-arm: Add support for non-coherent page tables
iommu/arm-smmu: Add support for non-coherent page table mappings
drivers/iommu/arm-smmu.c | 7 +++++++
drivers/iommu/io-pgtable-arm.c | 17 ++++++++++++-----
drivers/iommu/io-pgtable.h | 6 ++++++
3 files changed, 25 insertions(+), 5 deletions(-)
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation
next reply other threads:[~2019-01-17 9:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-17 9:27 Vivek Gautam [this message]
2019-01-17 9:27 ` [PATCH 1/2] iommu/io-pgtable-arm: Add support for non-coherent page tables Vivek Gautam
2019-01-21 13:12 ` Robin Murphy
2019-01-28 12:20 ` Vivek Gautam
2019-01-17 9:27 ` [PATCH 2/2] iommu/arm-smmu: Add support for non-coherent page table mappings Vivek Gautam
2019-01-20 0:01 ` Will Deacon
2019-01-21 6:05 ` Vivek Gautam
2019-01-22 5:43 ` Will Deacon
2019-01-29 10:43 ` Vivek Gautam
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