From: Will Deacon <will@kernel.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: robh@kernel.org, tomeu.vizoso@collabora.com,
narmstrong@baylibre.com, khilman@baylibre.com,
dri-devel@lists.freedesktop.org, steven.price@arm.com,
iommu@lists.linux-foundation.org,
alyssa.rosenzweig@collabora.com,
linux-amlogic@lists.infradead.org,
linux-arm-kernel@lists.infradead.org, jbrunet@baylibre.com
Subject: Re: [PATCH 1/3] iommu/io-pgtable-arm: Support coherency for Mali LPAE
Date: Mon, 21 Sep 2020 18:57:19 +0100 [thread overview]
Message-ID: <20200921175717.GF3141@willie-the-truck> (raw)
In-Reply-To: <d2a3ddb17b3270e268e2f1adf7682ea938823941.1600213517.git.robin.murphy@arm.com>
On Wed, Sep 16, 2020 at 12:51:05AM +0100, Robin Murphy wrote:
> Midgard GPUs have ACE-Lite master interfaces which allows systems to
> integrate them in an I/O-coherent manner. It seems that from the GPU's
> viewpoint, the rest of the system is its outer shareable domain, and so
> even when snoop signals are wired up, they are only emitted for outer
> shareable accesses. As such, setting the TTBR_SHARE_OUTER bit does
> indeed get coherent pagetable walks working nicely for the coherent
> T620 in the Arm Juno SoC.
I can't help but think some of this commentary deserves to be in the code
as well.
Do you know if this sort of thing is done for other SoCs too, or is this
just a Juno quirk?
Will
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next prev parent reply other threads:[~2020-09-21 17:57 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-15 23:51 [PATCH 0/3] drm: panfrost: Coherency support Robin Murphy
2020-09-15 23:51 ` [PATCH 1/3] iommu/io-pgtable-arm: Support coherency for Mali LPAE Robin Murphy
2020-09-21 17:57 ` Will Deacon [this message]
2020-09-21 21:53 ` Robin Murphy
2020-09-21 22:24 ` Will Deacon
2020-09-15 23:51 ` [PATCH 2/3] drm/panfrost: Support cache-coherent integrations Robin Murphy
2020-09-17 10:37 ` Steven Price
2020-09-15 23:51 ` [PATCH 3/3] arm64: dts: meson: Describe G12b GPU as coherent Robin Murphy
2020-09-16 8:26 ` Neil Armstrong
2020-10-05 8:15 ` Boris Brezillon
2020-10-05 8:34 ` Steven Price
2020-10-05 8:39 ` Boris Brezillon
2020-10-05 10:05 ` Steven Price
2020-09-16 14:54 ` Neil Armstrong
2020-09-16 14:54 ` [PATCH 0/3] drm: panfrost: Coherency support Neil Armstrong
2020-09-16 17:04 ` Alyssa Rosenzweig
2020-09-16 17:46 ` Rob Herring
2020-09-17 10:38 ` Steven Price
2020-09-17 10:51 ` Tomeu Vizoso
2020-09-17 11:00 ` Steven Price
2020-09-17 12:03 ` Alyssa Rosenzweig
2020-09-17 12:38 ` Robin Murphy
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