From: Janne Grunau <j@jannau.net>
To: iommu@lists.linux-foundation.org
Cc: devicetree@vger.kernel.org, Robin Murphy <robin.murphy@arm.com>,
Hector Martin <marcan@marcan.st>,
linux-kernel@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
linux-arm-kernel@lists.infradead.org,
Will Deacon <will@kernel.org>,
Alyssa Rosenzweig <alyssa@rosenzweig.io>,
Mark Kettenis <mark.kettenis@xs4all.nl>
Subject: [PATCH v2 0/4] iommu: M1 Pro/Max DART support
Date: Tue, 3 May 2022 08:22:57 +0200 [thread overview]
Message-ID: <20220503062301.20872-1-j@jannau.net> (raw)
Hej,
I've taken over this series to add support for DART on M1 Pro/Max from
Sven.
Since v1 we have discovered further differences in the PTE format. It
has four differences which makes it incompatible with the one in the
M1:
- the physical addresses are shifted left by 4 bits and and have 2 more
bits inside the PTE entries
- the read/write protection flags are at a different position
- the subpage protection feature is now mandatory. For Linux we can
just configure it to always allow access to the entire page.
- BIT(1) tags "uncached" mappings (used for the display controller)
The last difference is the most troublesome since it makes the PTE format
incomaptible with iopte_type(). Handling this inside io-pgtable-arm.c
seems manageable since DART supports just a single block size. It opens
the question at which point we decide that DART uses its own
io_pgtable_ops.
There is second type of DART (t8110) present on M1 Pro/Max SoCs which
uses the same PTE format as t6000.
Janne
Sven Peter (4):
dt-bindings: iommu: dart: add t6000 compatible
iommu/io-pgtable: Add DART subpage protection support
iommu/io-pgtable: Add DART PTE support for t6000
iommu: dart: Support t6000 variant
.../devicetree/bindings/iommu/apple,dart.yaml | 4 +-
drivers/iommu/apple-dart.c | 24 +++++-
drivers/iommu/io-pgtable-arm.c | 76 ++++++++++++++++++-
drivers/iommu/io-pgtable.c | 1 +
include/linux/io-pgtable.h | 3 +
5 files changed, 101 insertions(+), 7 deletions(-)
base-commit: 3123109284176b1532874591f7c81f3837bbdc17
--
2.35.1
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next reply other threads:[~2022-05-03 6:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-03 6:22 Janne Grunau [this message]
2022-05-03 6:22 ` [PATCH v2 1/4] dt-bindings: iommu: dart: add t6000 compatible Janne Grunau
2022-05-03 6:22 ` [PATCH v2 2/4] iommu/io-pgtable: Add DART subpage protection support Janne Grunau
2022-05-03 6:23 ` [PATCH v2 3/4] iommu/io-pgtable: Add DART PTE support for t6000 Janne Grunau
2022-05-03 6:23 ` [PATCH v2 4/4] iommu: dart: Support t6000 variant Janne Grunau
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