[PATCH 1/4] iommu/exynos: Set correct dma mask for SysMMU v5+

From: Sam Protsenko
Date: Sat Jul 02 2022 - 17:37:35 EST


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.

Originally-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Signed-off-by: Sam Protsenko <semen.protsenko@xxxxxxxxxx>
---
drivers/iommu/exynos-iommu.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 71f2018e23fe..28f8c8d93aa3 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -647,6 +647,14 @@ 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);
+ return ret;
+ }
+ }
+
/*
* use the first registered sysmmu device for performing
* dma mapping operations on iommu page tables (cpu cache flush)
--
2.30.2