On Mon, 2020-05-25 at 14:14 +0800, Yong Wu wrote:

On Sat, 2020-05-09 at 16:36 +0800, Chao Hao wrote:

quoted

In order to improve performance, we always disable STANDARD_AXI_MODE in
MISC_CTRL.

Signed-off-by: Chao Hao <redacted>
---
 drivers/iommu/mtk_iommu.c | 8 +++++++-
 drivers/iommu/mtk_iommu.h | 1 +
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index e7e7c7695ed1..9ede327a418d 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c

@@ -42,6 +42,8 @@
 #define F_INVLD_EN1				BIT(1)
 
 #define REG_MMU_MISC_CTRL			0x048
+#define F_MMU_STANDARD_AXI_MODE_BIT		(BIT(3) | BIT(19))
+
 #define REG_MMU_DCM_DIS				0x050
 
 #define REG_MMU_CTRL_REG			0x110

@@ -585,7 +587,11 @@ static int mtk_iommu_hw_init(const struct mtk_iommu_data *data)
 	}
 	writel_relaxed(0, data->base + REG_MMU_DCM_DIS);
 
-	if (data->plat_data->reset_axi) {
+	if (data->plat_data->has_misc_ctrl) {
+		regval = readl_relaxed(data->base + REG_MMU_MISC_CTRL);
+		regval &= ~F_MMU_STANDARD_AXI_MODE_BIT;
+		writel_relaxed(regval, data->base + REG_MMU_MISC_CTRL);
+	} else if (data->plat_data->reset_axi) {
 		/* The register is called STANDARD_AXI_MODE in this case */
 		writel_relaxed(0, data->base + REG_MMU_MISC_CTRL);
 	}

0x48 is either STANDARD_AXI_MODE or MISC_CTRL.

Thus, 

if (data->plat_data->reset_axi) {
   xxx
} else {  /* MISC_CTRL */
   xxx
}

No need add "has_misc_ctrl".

Thanks for you comment.
Only mm_iommu/m4u needs to set MISC_CTRL register and apu_iommu don't
need to set it. So I think we need to use has_misc_ctrl to distinguish
it.

quoted

diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h
index 1b6ea839b92c..d711ac630037 100644
--- a/drivers/iommu/mtk_iommu.h
+++ b/drivers/iommu/mtk_iommu.h

@@ -40,6 +40,7 @@ struct mtk_iommu_plat_data {
 
 	/* HW will use the EMI clock if there isn't the "bclk". */
 	bool                has_bclk;
+	bool		    has_misc_ctrl;
 	bool                has_vld_pa_rng;
 	bool                reset_axi;
 	unsigned char       larbid_remap[MTK_LARB_NR_MAX];