[PATCH v3 08/11] iommu/mediatek: Add a gap for the iova regions
From: Yong Wu <yong.wu@mediatek.com>
Date: 2023-02-14 03:13:35
Also in:
linux-devicetree, linux-iommu, linux-media, linux-mediatek, lkml
Subsystem:
iommu subsystem, mediatek iommu driver, the rest · Maintainers:
Joerg Roedel, Will Deacon, Yong Wu, Linus Torvalds
As the removed property in the vcodec dt-binding, the property is: dma-ranges = <0x1 0x0 0x0 0x40000000 0x0 0xfff00000>; The length is 0xfff0_0000 rather than 0x1_0000_0000, this means it requires 1M as a gap. This is because the end address for some vcodec HW is (address + size). If the size is 4G, the end address may be 0x2_0000_0000, and the width for vcodec register only is 32, then the HW may get the ZERO address. Currently the consumer's dma-ranges property doesn't work, IOMMU has to consider this case. Add a bigger gap(8M) for all the regions to avoid it. Signed-off-by: Yong Wu <yong.wu@mediatek.com> --- drivers/iommu/mtk_iommu.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 995e59cabf6c..4503fba72384 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c@@ -329,7 +329,7 @@ static LIST_HEAD(m4ulist); /* List all the M4U HWs */ #define for_each_m4u(data, head) list_for_each_entry(data, head, list) static const struct mtk_iommu_iova_region single_domain[] = { - {.iova_base = 0, .size = SZ_4G}, + {.iova_base = 0, .size = SZ_4G - SZ_8M}, }; #define MT8192_MULTI_REGION_MAX_NR 6
@@ -338,11 +338,11 @@ static const struct mtk_iommu_iova_region single_domain[] = { MT8192_MULTI_REGION_MAX_NR : 1) static const struct mtk_iommu_iova_region mt8192_multi_dom[MT8192_MULTI_REGION_NR] = { - { .iova_base = 0x0, .size = SZ_4G}, /* 0 ~ 4G */ + { .iova_base = 0x0, .size = SZ_4G - SZ_8M}, /* 0 ~ 4G, 8M as a gap. */ #if IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) - { .iova_base = SZ_4G, .size = SZ_4G}, /* 4G ~ 8G */ - { .iova_base = SZ_4G * 2, .size = SZ_4G}, /* 8G ~ 12G */ - { .iova_base = SZ_4G * 3, .size = SZ_4G}, /* 12G ~ 16G */ + { .iova_base = SZ_4G, .size = SZ_4G - SZ_8M}, /* 4G ~ 8G */ + { .iova_base = SZ_4G * 2, .size = SZ_4G - SZ_8M}, /* 8G ~ 12G */ + { .iova_base = SZ_4G * 3, .size = SZ_4G - SZ_8M}, /* 12G ~ 16G */ { .iova_base = 0x240000000ULL, .size = 0x4000000}, /* CCU0 */ { .iova_base = 0x244000000ULL, .size = 0x4000000}, /* CCU1 */
--
2.18.0
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