Re: [PATCH v3 3/7] iommu/mediatek: Disable STANDARD_AXI_MODE in MISC_CTRL

From: Yong Wu
Date: Mon May 25 2020 - 02:16:36 EST


On Sat, 2020-05-09 at 16:36 +0800, Chao Hao wrote:
> In order to improve performance, we always disable STANDARD_AXI_MODE in
> MISC_CTRL.
>
> Signed-off-by: Chao Hao <chao.hao@xxxxxxxxxxxx>
> ---
> 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".


> 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];