drm/msm/dpu: fix video mode DSC for DSI

Add width change in DPU timing for DSC compression case to work with
DSI video mode.
Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Signed-off-by: Jun Nie <jun.nie@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8650-QRD
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8650-HDK
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/596227/
Link: https://lore.kernel.org/r/20240530-msm-drm-dsc-dsi-video-upstream-4-v6-1-2ab1d334c657@linaro.orgSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c

@@ -564,7 +564,7 @@ bool dpu_encoder_use_dsc_merge(struct drm_encoder *drm_enc)
 	return (num_dsc > 0) && (num_dsc > intf_count);
 }
 
-static struct drm_dsc_config *dpu_encoder_get_dsc_config(struct drm_encoder *drm_enc)
+struct drm_dsc_config *dpu_encoder_get_dsc_config(struct drm_encoder *drm_enc)
 {
 	struct msm_drm_private *priv = drm_enc->dev->dev_private;
 	struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(drm_enc);

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h

@@ -339,6 +339,14 @@ static inline enum dpu_3d_blend_mode dpu_encoder_helper_get_3d_blend_mode(
  */
 unsigned int dpu_encoder_helper_get_dsc(struct dpu_encoder_phys *phys_enc);
 
+/**
+ * dpu_encoder_get_dsc_config - get DSC config for the DPU encoder
+ *   This helper function is used by physical encoder to get DSC config
+ *   used for this encoder.
+ * @drm_enc: Pointer to encoder structure
+ */
+struct drm_dsc_config *dpu_encoder_get_dsc_config(struct drm_encoder *drm_enc);
+
 /**
  * dpu_encoder_get_drm_fmt - return DRM fourcc format
  * @phys_enc: Pointer to physical encoder structure

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c

@@ -11,6 +11,7 @@
 #include "dpu_trace.h"
 #include "disp/msm_disp_snapshot.h"
 
+#include <drm/display/drm_dsc_helper.h>
 #include <drm/drm_managed.h>
 
 #define DPU_DEBUG_VIDENC(e, fmt, ...) DPU_DEBUG("enc%d intf%d " fmt, \
@@ -115,6 +116,23 @@ static void drm_mode_to_intf_timing_params(
 		timing->h_front_porch = timing->h_front_porch >> 1;
 		timing->hsync_pulse_width = timing->hsync_pulse_width >> 1;
 	}
+
+	/*
+	 * for DSI, if compression is enabled, then divide the horizonal active
+	 * timing parameters by compression ratio. bits of 3 components(R/G/B)
+	 * is compressed into bits of 1 pixel.
+	 */
+	if (phys_enc->hw_intf->cap->type != INTF_DP && timing->compression_en) {
+		struct drm_dsc_config *dsc =
+		       dpu_encoder_get_dsc_config(phys_enc->parent);
+		/*
+		 * TODO: replace drm_dsc_get_bpp_int with logic to handle
+		 * fractional part if there is fraction
+		 */
+		timing->width = timing->width * drm_dsc_get_bpp_int(dsc) /
+				(dsc->bits_per_component * 3);
+		timing->xres = timing->width;
+	}
 }
 
 static u32 get_horizontal_total(const struct dpu_hw_intf_timing_params *timing)