[PATCH v8 05/21] iommu/mediatek: Fix iova_to_phys PA start for 4GB mode

[Yong Wu]

In the 4GB mode, the physical address is remapped,

Here is the detailed remap relationship.
CPU PA         ->    HW PA
0x4000_0000          0x1_4000_0000 (Add bit32)
0x8000_0000          0x1_8000_0000 ...
0xc000_0000          0x1_c000_0000 ...
0x1_0000_0000        0x1_0000_0000 (No change)

The PA in the iova_to_phys that is got from v7s always is u32, But
from the CPU point of view, PA should add BIT(32) when PA < 0x4000_0000.

Fixes: 30e2fccf9512 ("iommu/mediatek: Enlarge the validate PA range
for 4GB mode")
Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
---
 drivers/iommu/mtk_iommu.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 1ddb2b7..fefc2e0 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -115,6 +115,19 @@ struct mtk_iommu_domain {
 
 static const struct iommu_ops mtk_iommu_ops;
 
+/*
+ * In M4U 4GB mode, the physical address is remapped as below:
+ *  CPU PA         ->   M4U HW PA
+ *  0x4000_0000         0x1_4000_0000 (Add bit32)
+ *  0x8000_0000         0x1_8000_0000 ...
+ *  0xc000_0000         0x1_c000_0000 ...
+ *  0x1_0000_0000       0x1_0000_0000 (No change)
+ *
+ * The PA in the iova_to_phys that is got from v7s always is u32, But from
+ * the CPU point of view, PA should add BIT(32) when PA < 0x4000_0000.
+ */
+#define MTK_IOMMU_4GB_MODE_REMAP_BASE	 0x40000000
+
 static LIST_HEAD(m4ulist);	/* List all the M4U HWs */
 
 #define for_each_m4u(data)	list_for_each_entry(data, &m4ulist, list)
@@ -409,7 +422,7 @@ static phys_addr_t mtk_iommu_iova_to_phys(struct iommu_domain *domain,
 	pa = dom->iop->iova_to_phys(dom->iop, iova);
 	spin_unlock_irqrestore(&dom->pgtlock, flags);
 
-	if (data->enable_4GB)
+	if (data->enable_4GB && pa < MTK_IOMMU_4GB_MODE_REMAP_BASE)
 		pa |= BIT_ULL(32);
 
 	return pa;
-- 
1.9.1