From b584862004020b3a555c48b549ed445d0a27e7e5 Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Tue, 22 Sep 2020 15:16:48 +0100 Subject: [PATCH] iommu/io-pgtable-arm: Support coherency for Mali LPAE commit 728da60da7c1ec1e21ae64648e376666de3c279c upstream. 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. Signed-off-by: Robin Murphy Tested-by: Neil Armstrong Reviewed-by: Steven Price Acked-by: Will Deacon Signed-off-by: Neil Armstrong Link: https://patchwork.freedesktop.org/patch/msgid/8df778355378127ea7eccc9521d6427e3e48d4f2.1600780574.git.robin.murphy@arm.com Signed-off-by: Greg Kroah-Hartman --- drivers/iommu/io-pgtable-arm.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c index a7a9bc08dcd1..bcfbd0e44a4a 100644 --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -417,7 +417,13 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data, << ARM_LPAE_PTE_ATTRINDX_SHIFT); } - if (prot & IOMMU_CACHE) + /* + * Also Mali has its own notions of shareability wherein its Inner + * domain covers the cores within the GPU, and its Outer domain is + * "outside the GPU" (i.e. either the Inner or System domain in CPU + * terms, depending on coherency). + */ + if (prot & IOMMU_CACHE && data->iop.fmt != ARM_MALI_LPAE) pte |= ARM_LPAE_PTE_SH_IS; else pte |= ARM_LPAE_PTE_SH_OS; @@ -1021,6 +1027,9 @@ 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: