linux-kernel - [PATCH v3 05/38] drm/msm/dp: splite msm_dp_ctrl_config

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Message-Id: <20250825-msm-dp-mst-v3-5-01faacfcdedd@oss.qualcomm.com>
Date: Mon, 25 Aug 2025 22:15:51 +0800
From: Yongxing Mou <yongxing.mou@....qualcomm.com>
To: Rob Clark <robin.clark@....qualcomm.com>,
        Dmitry Baryshkov <lumag@...nel.org>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Jessica Zhang <jessica.zhang@....qualcomm.com>,
        Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>
Cc: linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Yongxing Mou <yongxing.mou@....qualcomm.com>
Subject: [PATCH v3 05/38] drm/msm/dp: splite msm_dp_ctrl_config_ctrl() into
 link parts and stream parts

The DP_CONFIGURATION_CTRL register contains both link-level and
stream-specific fields. Currently, msm_dp_ctrl_config_ctrl() configures
all of them together, which makes it harder to support MST.

This patch separates the configuration into two functions:
- msm_dp_ctrl_config_ctrl_link(): handles link-related fields
- msm_dp_ctrl_config_ctrl_streams(): handles stream-specific fields

It also moves the link-related configuration out of
msm_dp_ctrl_configure_source_params().

Signed-off-by: Yongxing Mou <yongxing.mou@....qualcomm.com>
---
 drivers/gpu/drm/msm/dp/dp_ctrl.c | 49 +++++++++++++++++++++++++---------------
 1 file changed, 31 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index e1ff4c6bb4f0eed2e1ff931f12ba891cf81feffb..45d6c9a7f7ddaa049443253cbf4c6fc5feda3177 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -380,26 +380,41 @@ void msm_dp_ctrl_push_idle(struct msm_dp_ctrl *msm_dp_ctrl)
 	drm_dbg_dp(ctrl->drm_dev, "mainlink off\n");
 }
 
-static void msm_dp_ctrl_config_ctrl(struct msm_dp_ctrl_private *ctrl)
+static void msm_dp_ctrl_config_ctrl_streams(struct msm_dp_ctrl_private *ctrl,
+					    struct msm_dp_panel *msm_dp_panel)
 {
 	u32 config = 0, tbd;
+
+	config = msm_dp_read_link(ctrl, REG_DP_CONFIGURATION_CTRL);
+
+	if (msm_dp_panel->msm_dp_mode.out_fmt_is_yuv_420)
+		config |= DP_CONFIGURATION_CTRL_RGB_YUV; /* YUV420 */
+
+	tbd = msm_dp_link_get_test_bits_depth(ctrl->link,
+			msm_dp_panel->msm_dp_mode.bpp);
+
+	config |= tbd << DP_CONFIGURATION_CTRL_BPC_SHIFT;
+
+	if (msm_dp_panel->psr_cap.version)
+		config |= DP_CONFIGURATION_CTRL_SEND_VSC;
+
+	drm_dbg_dp(ctrl->drm_dev, "stream DP_CONFIGURATION_CTRL=0x%x\n", config);
+
+	msm_dp_write_link(ctrl, REG_DP_CONFIGURATION_CTRL, config);
+}
+
+static void msm_dp_ctrl_config_ctrl_link(struct msm_dp_ctrl_private *ctrl)
+{
+	u32 config = 0;
 	const u8 *dpcd = ctrl->panel->dpcd;
 
 	/* Default-> LSCLK DIV: 1/4 LCLK  */
 	config |= (2 << DP_CONFIGURATION_CTRL_LSCLK_DIV_SHIFT);
 
-	if (ctrl->panel->msm_dp_mode.out_fmt_is_yuv_420)
-		config |= DP_CONFIGURATION_CTRL_RGB_YUV; /* YUV420 */
-
 	/* Scrambler reset enable */
 	if (drm_dp_alternate_scrambler_reset_cap(dpcd))
 		config |= DP_CONFIGURATION_CTRL_ASSR;
 
-	tbd = msm_dp_link_get_test_bits_depth(ctrl->link,
-			ctrl->panel->msm_dp_mode.bpp);
-
-	config |= tbd << DP_CONFIGURATION_CTRL_BPC_SHIFT;
-
 	/* Num of Lanes */
 	config |= ((ctrl->link->link_params.num_lanes - 1)
 			<< DP_CONFIGURATION_CTRL_NUM_OF_LANES_SHIFT);
@@ -413,10 +428,7 @@ static void msm_dp_ctrl_config_ctrl(struct msm_dp_ctrl_private *ctrl)
 	config |= DP_CONFIGURATION_CTRL_STATIC_DYNAMIC_CN;
 	config |= DP_CONFIGURATION_CTRL_SYNC_ASYNC_CLK;
 
-	if (ctrl->panel->psr_cap.version)
-		config |= DP_CONFIGURATION_CTRL_SEND_VSC;
-
-	drm_dbg_dp(ctrl->drm_dev, "DP_CONFIGURATION_CTRL=0x%x\n", config);
+	drm_dbg_dp(ctrl->drm_dev, "link DP_CONFIGURATION_CTRL=0x%x\n", config);
 
 	msm_dp_write_link(ctrl, REG_DP_CONFIGURATION_CTRL, config);
 }
@@ -439,10 +451,7 @@ static void msm_dp_ctrl_configure_source_params(struct msm_dp_ctrl_private *ctrl
 {
 	u32 colorimetry_cfg, test_bits_depth, misc_val;
 
-	msm_dp_ctrl_lane_mapping(ctrl);
-	msm_dp_setup_peripheral_flush(ctrl);
-
-	msm_dp_ctrl_config_ctrl(ctrl);
+	msm_dp_ctrl_config_ctrl_streams(ctrl, ctrl->panel);
 
 	test_bits_depth = msm_dp_link_get_test_bits_depth(ctrl->link, ctrl->panel->msm_dp_mode.bpp);
 	colorimetry_cfg = msm_dp_link_get_colorimetry_config(ctrl->link);
@@ -1614,7 +1623,7 @@ static int msm_dp_ctrl_link_train(struct msm_dp_ctrl_private *ctrl,
 	u8 assr;
 	struct msm_dp_link_info link_info = {0};
 
-	msm_dp_ctrl_config_ctrl(ctrl);
+	msm_dp_ctrl_config_ctrl_link(ctrl);
 
 	link_info.num_lanes = ctrl->link->link_params.num_lanes;
 	link_info.rate = ctrl->link->link_params.rate;
@@ -2524,6 +2533,10 @@ int msm_dp_ctrl_on_stream(struct msm_dp_ctrl *msm_dp_ctrl)
 	 */
 	reinit_completion(&ctrl->video_comp);
 
+	msm_dp_ctrl_lane_mapping(ctrl);
+	msm_dp_setup_peripheral_flush(ctrl);
+	msm_dp_ctrl_config_ctrl_link(ctrl);
+
 	msm_dp_ctrl_configure_source_params(ctrl);
 
 	msm_dp_ctrl_config_msa(ctrl,

-- 
2.34.1