diff mbox series

[v4,08/11] iommu/mediatek: Add a gap for the iova regions

Message ID 20230215062544.8677-9-yong.wu@mediatek.com (mailing list archive)
State New, archived
Headers show
Series Adjust the dma-ranges for MTK IOMMU | expand

Commit Message

Yong Wu (吴勇) Feb. 15, 2023, 6:25 a.m. UTC 
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>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
Hi AngeloGioacchino,
I define a new macro for this, I think it is a small change, thus keep
you R-b.
Thanks.
---
 drivers/iommu/mtk_iommu.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

Comments

AngeloGioacchino Del Regno Feb. 15, 2023, 12:35 p.m. UTC | #1 
Il 15/02/23 07:25, Yong Wu ha scritto:
> 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>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
> Hi AngeloGioacchino,
> I define a new macro for this, I think it is a small change, thus keep
> you R-b.
> Thanks.

Hello!
You added a nice comment to the new definition describing that there's a 8M gap,
so it's completely fine; you can keep my R-b on this one just fine!

Regards,
Angelo
diff mbox series

Patch

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index fbfc5e4e56a8..e0264d5f1c9a 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -332,8 +332,10 @@  static LIST_HEAD(m4ulist);	/* List all the M4U HWs */
 
 #define for_each_m4u(data, head)  list_for_each_entry(data, head, list)
 
+#define MTK_IOMMU_IOVA_SZ_4G		(SZ_4G - SZ_8M) /* 8M as gap */
+
 static const struct mtk_iommu_iova_region single_domain[] = {
-	{.iova_base = 0,		.size = SZ_4G},
+	{.iova_base = 0,		.size = MTK_IOMMU_IOVA_SZ_4G},
 };
 
 #define MT8192_MULTI_REGION_NR_MAX	6
@@ -342,11 +344,11 @@  static const struct mtk_iommu_iova_region single_domain[] = {
 				 MT8192_MULTI_REGION_NR_MAX : 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 = MTK_IOMMU_IOVA_SZ_4G},	/* 0 ~ 4G,  */
 	#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 = MTK_IOMMU_IOVA_SZ_4G},	/* 4G ~ 8G */
+	{ .iova_base = SZ_4G * 2,	.size = MTK_IOMMU_IOVA_SZ_4G},	/* 8G ~ 12G */
+	{ .iova_base = SZ_4G * 3,	.size = MTK_IOMMU_IOVA_SZ_4G},	/* 12G ~ 16G */
 
 	{ .iova_base = 0x240000000ULL,	.size = 0x4000000},	/* CCU0 */
 	{ .iova_base = 0x244000000ULL,	.size = 0x4000000},	/* CCU1 */