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From: Robin Murphy <robin.murphy@arm.com>
To: will@kernel.org, robh@kernel.org, tomeu.vizoso@collabora.com,
	steven.price@arm.com, alyssa.rosenzweig@collabora.com,
	khilman@baylibre.com, narmstrong@baylibre.com,
	jbrunet@baylibre.com
Cc: linux-amlogic@lists.infradead.org,
	iommu@lists.linux-foundation.org,
	dri-devel@lists.freedesktop.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/3] iommu/io-pgtable-arm: Support coherency for Mali LPAE
Date: Wed, 16 Sep 2020 00:51:05 +0100	[thread overview]
Message-ID: <d2a3ddb17b3270e268e2f1adf7682ea938823941.1600213517.git.robin.murphy@arm.com> (raw)
In-Reply-To: <cover.1600213517.git.robin.murphy@arm.com>

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.

Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
 drivers/iommu/io-pgtable-arm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index dc7bcf858b6d..e47012006dcc 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -440,7 +440,7 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
 				<< ARM_LPAE_PTE_ATTRINDX_SHIFT);
 	}
 
-	if (prot & IOMMU_CACHE)
+	if (prot & IOMMU_CACHE && data->iop.fmt != ARM_MALI_LPAE)
 		pte |= ARM_LPAE_PTE_SH_IS;
 	else
 		pte |= ARM_LPAE_PTE_SH_OS;
@@ -1049,6 +1049,9 @@ arm_mali_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
 	cfg->arm_mali_lpae_cfg.transtab = virt_to_phys(data->pgd) |
 					  ARM_MALI_LPAE_TTBR_READ_INNER |
 					  ARM_MALI_LPAE_TTBR_ADRMODE_TABLE;
+	if (cfg->coherent_walk)
+		cfg->arm_mali_lpae_cfg.transtab |= ARM_MALI_LPAE_TTBR_SHARE_OUTER;
+
 	return &data->iop;
 
 out_free_data:
-- 
2.28.0.dirty

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  reply	other threads:[~2020-09-15 23:51 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 ` Robin Murphy [this message]
2020-09-21 17:57   ` [PATCH 1/3] iommu/io-pgtable-arm: Support coherency for Mali LPAE Will Deacon
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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