[PATCH v3 15/32] iommu/mtk_v1: implement iova_to_phys_length

From: Guanghui Feng

Date: Wed Jun 03 2026 - 11:35:45 EST


Implement iova_to_phys_length for MediaTek v1 IOMMU driver,
returning the actual PTE mapping size.
Also fix pre-existing bug: add page offset to physical address.

Signed-off-by: Guanghui Feng <guanghuifeng@xxxxxxxxxxxxxxxxx>
---
drivers/iommu/mtk_iommu_v1.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index ac97dd2868d4..da41dda7620b 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -393,7 +393,9 @@ static size_t mtk_iommu_v1_unmap(struct iommu_domain *domain, unsigned long iova
return size;
}

-static phys_addr_t mtk_iommu_v1_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
+static phys_addr_t mtk_iommu_v1_iova_to_phys_length(struct iommu_domain *domain,
+ dma_addr_t iova,
+ size_t *mapped_length)
{
struct mtk_iommu_v1_domain *dom = to_mtk_domain(domain);
unsigned long flags;
@@ -404,6 +406,13 @@ static phys_addr_t mtk_iommu_v1_iova_to_phys(struct iommu_domain *domain, dma_ad
pa = pa & (~(MT2701_IOMMU_PAGE_SIZE - 1));
spin_unlock_irqrestore(&dom->pgtlock, flags);

+ if (!pa)
+ return PHYS_ADDR_MAX;
+
+ pa |= (iova & (MT2701_IOMMU_PAGE_SIZE - 1));
+ if (mapped_length)
+ *mapped_length = MT2701_IOMMU_PAGE_SIZE;
+
return pa;
}

@@ -590,7 +599,7 @@ static const struct iommu_ops mtk_iommu_v1_ops = {
.attach_dev = mtk_iommu_v1_attach_device,
.map_pages = mtk_iommu_v1_map,
.unmap_pages = mtk_iommu_v1_unmap,
- .iova_to_phys = mtk_iommu_v1_iova_to_phys,
+ .iova_to_phys_length = mtk_iommu_v1_iova_to_phys_length,
.free = mtk_iommu_v1_domain_free,
}
};
--
2.43.7