Re: [PATCH v1 03/14] drm/msm/dp: add configure mainlink_levels base on lane number

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>]

On 23/01/2023 20:24, Kuogee Hsieh wrote:
> Mainlink_levels determined when two actions to take place by hardware,
> a new BS sequence due to start of video and a static HW MVID is sent
> to panel. This patch add function to configure mainlink level properly
> base on lane number.
>
> Signed-off-by: Kuogee Hsieh <quic_khsieh@xxxxxxxxxxx>
> ---
>   drivers/gpu/drm/msm/dp/dp_catalog.c | 37 ++++++++++++++++++++++++++++++++++++-
>   drivers/gpu/drm/msm/dp/dp_catalog.h |  4 +++-
>   drivers/gpu/drm/msm/dp/dp_ctrl.c    |  4 ++++
>   3 files changed, 43 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c b/drivers/gpu/drm/msm/dp/dp_catalog.c
> index 676279d..7ac37d8 100644
> --- a/drivers/gpu/drm/msm/dp/dp_catalog.c
> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.c
> @@ -1,6 +1,7 @@
>   // SPDX-License-Identifier: GPL-2.0-only
>   /*
> - * Copyright (c) 2017-2020, The Linux Foundation. All rights reserved.
> + * Copyright (c) 2017-2023, The Linux Foundation. All rights reserved.
> + * Copyright (c) 2021. Qualcomm Innovation Center, Inc. All rights reserved
>    */
>   
>   #define pr_fmt(fmt)	"[drm-dp] %s: " fmt, __func__
> @@ -359,6 +360,40 @@ void dp_catalog_ctrl_lane_mapping(struct dp_catalog *dp_catalog)
>   			ln_mapping);
>   }
>   
> +void dp_catalog_ctrl_mainlink_levels(struct dp_catalog *dp_catalog,
> +					u8 lane_cnt)
> +{
> +	struct dp_catalog_private *catalog = container_of(dp_catalog,
> +				struct dp_catalog_private, dp_catalog);
> +
> +	u32 mainlink_levels, safe_to_exit_level = 14;
> +
> +	switch (lane_cnt) {
> +	case 1:
> +		safe_to_exit_level = 14;
> +		break;
> +	case 2:
> +		safe_to_exit_level = 8;
> +		break;
> +	case 4:
> +		safe_to_exit_level = 5;
> +		break;
> +	default:
> +		drm_dbg_dp(catalog->drm_dev, "setting the default safe_to_exit_level=%u\n",
> +				safe_to_exit_level);

So, set it here rather than somewhere at the top of the function.

> +		break;
> +	}
> +
> +	mainlink_levels = dp_read_link(catalog, REG_DP_MAINLINK_LEVELS);
> +	mainlink_levels &= 0xFE0;
> +	mainlink_levels |= safe_to_exit_level;
> +
> +	drm_dbg_dp(catalog->drm_dev, "mainlink_level=0x%x, safe_to_exit_level=0x%x\n",
> +		mainlink_levels, safe_to_exit_level);
> +
> +	dp_write_link(catalog, REG_DP_MAINLINK_LEVELS, mainlink_levels);
> +}
> +
>   void dp_catalog_ctrl_mainlink_ctrl(struct dp_catalog *dp_catalog,
>   						bool enable)
>   {
> diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.h b/drivers/gpu/drm/msm/dp/dp_catalog.h
> index 1f717f4..990c162 100644
> --- a/drivers/gpu/drm/msm/dp/dp_catalog.h
> +++ b/drivers/gpu/drm/msm/dp/dp_catalog.h
> @@ -1,6 +1,7 @@
>   /* SPDX-License-Identifier: GPL-2.0-only */
>   /*
> - * Copyright (c) 2017-2020, The Linux Foundation. All rights reserved.
> + * Copyright (c) 2017-2023, The Linux Foundation. All rights reserved.
> + * Copyright (c) 2021. Qualcomm Innovation Center, Inc. All rights reserved
>    */
>   
>   #ifndef _DP_CATALOG_H_
> @@ -92,6 +93,7 @@ u32 dp_catalog_aux_get_irq(struct dp_catalog *dp_catalog);
>   void dp_catalog_ctrl_state_ctrl(struct dp_catalog *dp_catalog, u32 state);
>   void dp_catalog_ctrl_config_ctrl(struct dp_catalog *dp_catalog, u32 config);
>   void dp_catalog_ctrl_lane_mapping(struct dp_catalog *dp_catalog);
> +void dp_catalog_ctrl_mainlink_levels(struct dp_catalog *dp_catalog, u8 lane_cnt);
>   void dp_catalog_ctrl_mainlink_ctrl(struct dp_catalog *dp_catalog, bool enable);
>   void dp_catalog_ctrl_config_misc(struct dp_catalog *dp_catalog, u32 cc, u32 tb);
>   void dp_catalog_ctrl_config_msa(struct dp_catalog *dp_catalog, u32 rate,
> diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> index dd26ca6..959a78c 100644
> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
> @@ -161,6 +161,8 @@ static void dp_ctrl_configure_source_params(struct dp_ctrl_private *ctrl)
>   	u32 cc, tb;
>   
>   	dp_catalog_ctrl_lane_mapping(ctrl->catalog);
> +	dp_catalog_ctrl_mainlink_levels(ctrl->catalog,
> +				ctrl->link->link_params.num_lanes);
>   	dp_catalog_ctrl_mainlink_ctrl(ctrl->catalog, true);
>   
>   	dp_ctrl_config_ctrl(ctrl);
> @@ -1296,6 +1298,8 @@ static int dp_ctrl_setup_main_link(struct dp_ctrl_private *ctrl,
>   {
>   	int ret = 0;
>   
> +	dp_catalog_ctrl_mainlink_levels(ctrl->catalog,
> +				ctrl->link->link_params.num_lanes);
>   	dp_catalog_ctrl_mainlink_ctrl(ctrl->catalog, true);
>   
>   	if (ctrl->link->sink_request & DP_TEST_LINK_PHY_TEST_PATTERN)

--
With best wishes
Dmitry