drm/msm/dpu: allow sharing SSPP between planes

Since SmartDMA planes provide two rectangles, it is possible to use them
to drive two different DRM planes, first plane getting the rect_0,
another one using rect_1 of the same SSPP. The sharing algorithm is
pretty simple, it requires that each of the planes can be driven by the
single rectangle and only consecutive planes are considered.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/650441/
Link: https://lore.kernel.org/r/20250426-dpu-share-sspp-v7-1-6f4c719e373c@oss.qualcomm.com
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Author: lumag

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

@@ -915,10 +915,9 @@ static int dpu_plane_atomic_check_nosspp(struct drm_plane *plane,
 	return 0;
 }
 
-static int dpu_plane_is_multirect_parallel_capable(struct dpu_hw_sspp *sspp,
-						   struct dpu_sw_pipe_cfg *pipe_cfg,
-						   const struct msm_format *fmt,
-						   uint32_t max_linewidth)
+static int dpu_plane_is_multirect_capable(struct dpu_hw_sspp *sspp,
+					  struct dpu_sw_pipe_cfg *pipe_cfg,
+					  const struct msm_format *fmt)
 {
 	if (drm_rect_width(&pipe_cfg->src_rect) != drm_rect_width(&pipe_cfg->dst_rect) ||
 	    drm_rect_height(&pipe_cfg->src_rect) != drm_rect_height(&pipe_cfg->dst_rect))
@@ -930,17 +929,34 @@ static int dpu_plane_is_multirect_parallel_capable(struct dpu_hw_sspp *sspp,
 	if (MSM_FORMAT_IS_YUV(fmt))
 		return false;
 
-	if (MSM_FORMAT_IS_UBWC(fmt) &&
-	    drm_rect_width(&pipe_cfg->src_rect) > max_linewidth / 2)
-		return false;
-
 	if (!test_bit(DPU_SSPP_SMART_DMA_V1, &sspp->cap->features) &&
 	    !test_bit(DPU_SSPP_SMART_DMA_V2, &sspp->cap->features))
 		return false;
 
 	return true;
 }
 
+static int dpu_plane_is_parallel_capable(struct dpu_sw_pipe_cfg *pipe_cfg,
+					 const struct msm_format *fmt,
+					 uint32_t max_linewidth)
+{
+	if (MSM_FORMAT_IS_UBWC(fmt) &&
+	    drm_rect_width(&pipe_cfg->src_rect) > max_linewidth / 2)
+		return false;
+
+	return true;
+}
+
+static int dpu_plane_is_multirect_parallel_capable(struct dpu_hw_sspp *sspp,
+						   struct dpu_sw_pipe_cfg *pipe_cfg,
+						   const struct msm_format *fmt,
+						   uint32_t max_linewidth)
+{
+	return dpu_plane_is_multirect_capable(sspp, pipe_cfg, fmt) &&
+		dpu_plane_is_parallel_capable(pipe_cfg, fmt, max_linewidth);
+}
+
+
 static int dpu_plane_atomic_check_sspp(struct drm_plane *plane,
 				       struct drm_atomic_state *state,
 				       const struct drm_crtc_state *crtc_state)
@@ -1002,6 +1018,69 @@ static bool dpu_plane_try_multirect_parallel(struct dpu_sw_pipe *pipe, struct dp
 	return true;
 }
 
+static int dpu_plane_try_multirect_shared(struct dpu_plane_state *pstate,
+					  struct dpu_plane_state *prev_adjacent_pstate,
+					  const struct msm_format *fmt,
+					  uint32_t max_linewidth)
+{
+	struct dpu_sw_pipe *pipe = &pstate->pipe;
+	struct dpu_sw_pipe *r_pipe = &pstate->r_pipe;
+	struct dpu_sw_pipe_cfg *pipe_cfg = &pstate->pipe_cfg;
+	struct dpu_sw_pipe *prev_pipe = &prev_adjacent_pstate->pipe;
+	struct dpu_sw_pipe_cfg *prev_pipe_cfg = &prev_adjacent_pstate->pipe_cfg;
+	const struct msm_format *prev_fmt = msm_framebuffer_format(prev_adjacent_pstate->base.fb);
+	u16 max_tile_height = 1;
+
+	if (prev_adjacent_pstate->r_pipe.sspp != NULL ||
+	    prev_pipe->multirect_mode != DPU_SSPP_MULTIRECT_NONE)
+		return false;
+
+	if (!dpu_plane_is_multirect_capable(pipe->sspp, pipe_cfg, fmt) ||
+	    !dpu_plane_is_multirect_capable(prev_pipe->sspp, prev_pipe_cfg, prev_fmt))
+		return false;
+
+	if (MSM_FORMAT_IS_UBWC(fmt))
+		max_tile_height = max(max_tile_height, fmt->tile_height);
+
+	if (MSM_FORMAT_IS_UBWC(prev_fmt))
+		max_tile_height = max(max_tile_height, prev_fmt->tile_height);
+
+	r_pipe->multirect_index = DPU_SSPP_RECT_SOLO;
+	r_pipe->multirect_mode = DPU_SSPP_MULTIRECT_NONE;
+
+	r_pipe->sspp = NULL;
+
+	if (dpu_plane_is_parallel_capable(pipe_cfg, fmt, max_linewidth) &&
+	    dpu_plane_is_parallel_capable(prev_pipe_cfg, prev_fmt, max_linewidth) &&
+	    (pipe_cfg->dst_rect.x1 >= prev_pipe_cfg->dst_rect.x2 ||
+	     prev_pipe_cfg->dst_rect.x1 >= pipe_cfg->dst_rect.x2)) {
+		pipe->sspp = prev_pipe->sspp;
+
+		pipe->multirect_index = DPU_SSPP_RECT_1;
+		pipe->multirect_mode = DPU_SSPP_MULTIRECT_PARALLEL;
+
+		prev_pipe->multirect_index = DPU_SSPP_RECT_0;
+		prev_pipe->multirect_mode = DPU_SSPP_MULTIRECT_PARALLEL;
+
+		return true;
+	}
+
+	if (pipe_cfg->dst_rect.y1 >= prev_pipe_cfg->dst_rect.y2 + 2 * max_tile_height ||
+	    prev_pipe_cfg->dst_rect.y1 >= pipe_cfg->dst_rect.y2 + 2 * max_tile_height) {
+		pipe->sspp = prev_pipe->sspp;
+
+		pipe->multirect_index = DPU_SSPP_RECT_1;
+		pipe->multirect_mode = DPU_SSPP_MULTIRECT_TIME_MX;
+
+		prev_pipe->multirect_index = DPU_SSPP_RECT_0;
+		prev_pipe->multirect_mode = DPU_SSPP_MULTIRECT_TIME_MX;
+
+		return true;
+	}
+
+	return false;
+}
+
 static int dpu_plane_atomic_check(struct drm_plane *plane,
 				  struct drm_atomic_state *state)
 {
@@ -1102,13 +1181,14 @@ static int dpu_plane_virtual_atomic_check(struct drm_plane *plane,
 static int dpu_plane_virtual_assign_resources(struct drm_crtc *crtc,
 					      struct dpu_global_state *global_state,
 					      struct drm_atomic_state *state,
-					      struct drm_plane_state *plane_state)
+					      struct drm_plane_state *plane_state,
+					      struct drm_plane_state *prev_adjacent_plane_state)
 {
 	const struct drm_crtc_state *crtc_state = NULL;
 	struct drm_plane *plane = plane_state->plane;
 	struct dpu_kms *dpu_kms = _dpu_plane_get_kms(plane);
 	struct dpu_rm_sspp_requirements reqs;
-	struct dpu_plane_state *pstate;
+	struct dpu_plane_state *pstate, *prev_adjacent_pstate;
 	struct dpu_sw_pipe *pipe;
 	struct dpu_sw_pipe *r_pipe;
 	struct dpu_sw_pipe_cfg *pipe_cfg;
@@ -1120,6 +1200,8 @@ static int dpu_plane_virtual_assign_resources(struct drm_crtc *crtc,
 							   plane_state->crtc);
 
 	pstate = to_dpu_plane_state(plane_state);
+	prev_adjacent_pstate = prev_adjacent_plane_state ?
+		to_dpu_plane_state(prev_adjacent_plane_state) : NULL;
 	pipe = &pstate->pipe;
 	r_pipe = &pstate->r_pipe;
 	pipe_cfg = &pstate->pipe_cfg;
@@ -1138,24 +1220,42 @@ static int dpu_plane_virtual_assign_resources(struct drm_crtc *crtc,
 
 	reqs.rot90 = drm_rotation_90_or_270(plane_state->rotation);
 
-	pipe->sspp = dpu_rm_reserve_sspp(&dpu_kms->rm, global_state, crtc, &reqs);
-	if (!pipe->sspp)
-		return -ENODEV;
+	if (drm_rect_width(&r_pipe_cfg->src_rect) == 0) {
+		if (!prev_adjacent_pstate ||
+		    !dpu_plane_try_multirect_shared(pstate, prev_adjacent_pstate, fmt,
+						    dpu_kms->catalog->caps->max_linewidth)) {
+			pipe->sspp = dpu_rm_reserve_sspp(&dpu_kms->rm, global_state, crtc, &reqs);
+			if (!pipe->sspp)
+				return -ENODEV;
 
-	if (!dpu_plane_try_multirect_parallel(pipe, pipe_cfg, r_pipe, r_pipe_cfg,
-					      pipe->sspp,
-					      msm_framebuffer_format(plane_state->fb),
-					      dpu_kms->catalog->caps->max_linewidth)) {
-		/* multirect is not possible, use two SSPP blocks */
-		r_pipe->sspp = dpu_rm_reserve_sspp(&dpu_kms->rm, global_state, crtc, &reqs);
-		if (!r_pipe->sspp)
+			r_pipe->sspp = NULL;
+
+			pipe->multirect_index = DPU_SSPP_RECT_SOLO;
+			pipe->multirect_mode = DPU_SSPP_MULTIRECT_NONE;
+
+			r_pipe->multirect_index = DPU_SSPP_RECT_SOLO;
+			r_pipe->multirect_mode = DPU_SSPP_MULTIRECT_NONE;
+		}
+	} else {
+		pipe->sspp = dpu_rm_reserve_sspp(&dpu_kms->rm, global_state, crtc, &reqs);
+		if (!pipe->sspp)
 			return -ENODEV;
 
-		pipe->multirect_index = DPU_SSPP_RECT_SOLO;
-		pipe->multirect_mode = DPU_SSPP_MULTIRECT_NONE;
+		if (!dpu_plane_try_multirect_parallel(pipe, pipe_cfg, r_pipe, r_pipe_cfg,
+						      pipe->sspp,
+						      msm_framebuffer_format(plane_state->fb),
+						      dpu_kms->catalog->caps->max_linewidth)) {
+			/* multirect is not possible, use two SSPP blocks */
+			r_pipe->sspp = dpu_rm_reserve_sspp(&dpu_kms->rm, global_state, crtc, &reqs);
+			if (!r_pipe->sspp)
+				return -ENODEV;
 
-		r_pipe->multirect_index = DPU_SSPP_RECT_SOLO;
-		r_pipe->multirect_mode = DPU_SSPP_MULTIRECT_NONE;
+			pipe->multirect_index = DPU_SSPP_RECT_SOLO;
+			pipe->multirect_mode = DPU_SSPP_MULTIRECT_NONE;
+
+			r_pipe->multirect_index = DPU_SSPP_RECT_SOLO;
+			r_pipe->multirect_mode = DPU_SSPP_MULTIRECT_NONE;
+		}
 	}
 
 	return dpu_plane_atomic_check_sspp(plane, state, crtc_state);
@@ -1168,6 +1268,7 @@ int dpu_assign_plane_resources(struct dpu_global_state *global_state,
 			       unsigned int num_planes)
 {
 	unsigned int i;
+	struct drm_plane_state *prev_adjacent_plane_state = NULL;
 
 	for (i = 0; i < num_planes; i++) {
 		struct drm_plane_state *plane_state = states[i];
@@ -1177,9 +1278,12 @@ int dpu_assign_plane_resources(struct dpu_global_state *global_state,
 			continue;
 
 		int ret = dpu_plane_virtual_assign_resources(crtc, global_state,
-							 state, plane_state);
+							     state, plane_state,
+							     prev_adjacent_plane_state);
 		if (ret)
-			return ret;
+			break;
+
+		prev_adjacent_plane_state = plane_state;
 	}
 
 	return 0;