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From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Joerg Roedel <joro@8bytes.org>
Cc: iommu@lists.linux-foundation.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	Jordan Crouse <jcrouse@codeaurora.org>,
	Rob Clark <robdclark@gmail.com>,
	Akhil P Oommen <akhilpo@codeaurora.org>,
	Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Subject: [PATCH] iommu/io-pgtable-arm: Allow non-coherent masters to use system cache
Date: Thu, 24 Dec 2020 12:10:07 +0530	[thread overview]
Message-ID: <20201224064007.2339-1-saiprakash.ranjan@codeaurora.org> (raw)

commit ecd7274fb4cd ("iommu: Remove unused IOMMU_SYS_CACHE_ONLY flag")
removed unused IOMMU_SYS_CACHE_ONLY prot flag and along with it went
the memory type setting required for the non-coherent masters to use
system cache. Now that system cache support for GPU is added, we will
need to mark the memory as normal sys-cached for GPU to use system cache.
Without this, the system cache lines are not allocated for GPU. We use
the IO_PGTABLE_QUIRK_ARM_OUTER_WBWA quirk instead of a page protection
flag as the flag cannot be exposed via DMA api because of no in-tree
users.

Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
---
 drivers/iommu/io-pgtable-arm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 7c9ea9d7874a..3fb7de8304a2 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -415,6 +415,9 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
 		else if (prot & IOMMU_CACHE)
 			pte |= (ARM_LPAE_MAIR_ATTR_IDX_CACHE
 				<< ARM_LPAE_PTE_ATTRINDX_SHIFT);
+		else if (data->iop.cfg.quirks & IO_PGTABLE_QUIRK_ARM_OUTER_WBWA)
+			pte |= (ARM_LPAE_MAIR_ATTR_IDX_INC_OCACHE
+				<< ARM_LPAE_PTE_ATTRINDX_SHIFT);
 	}
 
 	if (prot & IOMMU_CACHE)
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation


             reply	other threads:[~2020-12-24  6:41 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-24  6:40 Sai Prakash Ranjan [this message]
2021-01-06 11:56 ` [PATCH] iommu/io-pgtable-arm: Allow non-coherent masters to use system cache Will Deacon
2021-01-07  6:35   ` Sai Prakash Ranjan
2021-01-07 16:57   ` isaacm
2021-01-08  5:47     ` Sai Prakash Ranjan
2021-01-08 18:09       ` isaacm
2021-01-11  4:38         ` Sai Prakash Ranjan
2021-01-08 18:18       ` Will Deacon
2021-01-08 19:50         ` isaacm
2021-01-11  4:56         ` Sai Prakash Ranjan

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