linux-kernel - [PATCH v3 3/6] iommu/exynos: Set correct dma mask for SysMMU v5+

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Message-Id: <20220714165550.8884-4-semen.protsenko@linaro.org>
Date:   Thu, 14 Jul 2022 19:55:47 +0300
From:   Sam Protsenko <semen.protsenko@...aro.org>
To:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc:     Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Janghyuck Kim <janghyuck.kim@...sung.com>,
        Cho KyongHo <pullip.cho@...sung.com>,
        Daniel Mentz <danielmentz@...gle.com>,
        David Virag <virag.david003@...il.com>,
        Sumit Semwal <sumit.semwal@...aro.org>, iommu@...ts.linux.dev,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3 3/6] iommu/exynos: Set correct dma mask for SysMMU v5+

SysMMU v5+ supports 36 bit physical address space. Set corresponding DMA
mask to avoid falling back to SWTLBIO usage in dma_map_single() because
of failed dma_capable() check.

The original code for this fix was suggested by Marek.

Signed-off-by: Sam Protsenko <semen.protsenko@...aro.org>
Co-developed-by: Marek Szyprowski <m.szyprowski@...sung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
---
Changes in v3:
  - Added Krzysztof's Acked-by tag

Changes in v2:
  - Handled failed dma_set_mask() call
  - Replaced "Originally-by" tag by "Co-developed-by" + SoB tags

 drivers/iommu/exynos-iommu.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index c85db9dab851..494f7d7aa9c5 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -646,6 +646,14 @@ static int exynos_sysmmu_probe(struct platform_device *pdev)
 		}
 	}
 
+	if (MMU_MAJ_VER(data->version) >= 5) {
+		ret = dma_set_mask(dev, DMA_BIT_MASK(36));
+		if (ret) {
+			dev_err(dev, "Unable to set DMA mask: %d\n", ret);
+			goto err_dma_set_mask;
+		}
+	}
+
 	/*
 	 * use the first registered sysmmu device for performing
 	 * dma mapping operations on iommu page tables (cpu cache flush)
@@ -657,6 +665,8 @@ static int exynos_sysmmu_probe(struct platform_device *pdev)
 
 	return 0;
 
+err_dma_set_mask:
+	iommu_device_unregister(&data->iommu);
 err_iommu_register:
 	iommu_device_sysfs_remove(&data->iommu);
 	return ret;
-- 
2.30.2