drm/amd/display: rename function to add otg master for stream

We are renaming acquire first free pipe to add
otg master pipe for stream because the former name
doesn't indicate that it acquires the first free pipe
to use as an otg master pipe. This could cause coding
errors if someone uses it to acquire a different pipe type.
Reviewed-by: Jun Lei <jun.lei@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Wenjing Liu <wenjing.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_resource.c

@@ -1825,7 +1825,7 @@ static int acquire_first_split_pipe(
 			return i;
 		}
 	}
-	return UNABLE_TO_SPLIT;
+	return FREE_PIPE_INDEX_NOT_FOUND;
 }
 
 /* For each OPP head of an OTG master, add top plane at plane index 0.
@@ -1953,6 +1953,66 @@ static bool acquire_secondary_dpp_pipes_and_add_plane(
 	return true;
 }
 
+/*
+ * Acquire a pipe as OTG master and assign to the stream in new dc context.
+ * return - true if OTG master pipe is acquired and new dc context is updated.
+ * false if it fails to acquire an OTG master pipe for this stream.
+ *
+ * In the example below, we acquired pipe 0 as OTG master pipe for the stream.
+ * After the function its Inter-pipe Relation is represented by the diagram
+ * below.
+ *
+ *       Inter-pipe Relation
+ *        __________________________________________________
+ *       |PIPE IDX|   DPP PIPES   | OPP HEADS | OTG MASTER  |
+ *       |        |               |           |             |
+ *       |   0    |               |blank ------------------ |
+ *       |________|_______________|___________|_____________|
+ */
+static bool acquire_otg_master_pipe_for_stream(
+		struct dc_state *new_ctx,
+		const struct resource_pool *pool,
+		struct dc_stream_state *stream)
+{
+	/* TODO: Move this function to DCN specific resource file and acquire
+	 * DSC resource here. The reason is that the function should have the
+	 * same level of responsibility as when we acquire secondary OPP head.
+	 * We acquire DSC when we acquire secondary OPP head, so we should
+	 * acquire DSC when we acquire OTG master.
+	 */
+	int pipe_idx;
+	struct pipe_ctx *pipe_ctx = NULL;
+
+	pipe_idx = resource_find_any_free_pipe(&new_ctx->res_ctx, pool);
+	if (pipe_idx != FREE_PIPE_INDEX_NOT_FOUND) {
+		pipe_ctx = &new_ctx->res_ctx.pipe_ctx[pipe_idx];
+		memset(pipe_ctx, 0, sizeof(*pipe_ctx));
+		pipe_ctx->pipe_idx = pipe_idx;
+		pipe_ctx->stream_res.tg = pool->timing_generators[pipe_idx];
+		pipe_ctx->plane_res.mi = pool->mis[pipe_idx];
+		pipe_ctx->plane_res.hubp = pool->hubps[pipe_idx];
+		pipe_ctx->plane_res.ipp = pool->ipps[pipe_idx];
+		pipe_ctx->plane_res.xfm = pool->transforms[pipe_idx];
+		pipe_ctx->plane_res.dpp = pool->dpps[pipe_idx];
+		pipe_ctx->stream_res.opp = pool->opps[pipe_idx];
+		if (pool->dpps[pipe_idx])
+			pipe_ctx->plane_res.mpcc_inst = pool->dpps[pipe_idx]->inst;
+
+		if (pipe_idx >= pool->timing_generator_count) {
+			int tg_inst = pool->timing_generator_count - 1;
+
+			pipe_ctx->stream_res.tg = pool->timing_generators[tg_inst];
+			pipe_ctx->stream_res.opp = pool->opps[tg_inst];
+		}
+
+		pipe_ctx->stream = stream;
+	} else {
+		pipe_idx = acquire_first_split_pipe(&new_ctx->res_ctx, pool, stream);
+	}
+
+	return pipe_idx != FREE_PIPE_INDEX_NOT_FOUND;
+}
+
 bool dc_add_plane_to_context(
 		const struct dc *dc,
 		struct dc_stream_state *stream,
@@ -2372,42 +2432,6 @@ void update_audio_usage(
 	}
 }
 
-static int acquire_first_free_pipe(
-		struct resource_context *res_ctx,
-		const struct resource_pool *pool,
-		struct dc_stream_state *stream)
-{
-	int i;
-
-	for (i = 0; i < pool->pipe_count; i++) {
-		if (!res_ctx->pipe_ctx[i].stream) {
-			struct pipe_ctx *pipe_ctx = &res_ctx->pipe_ctx[i];
-
-			pipe_ctx->stream_res.tg = pool->timing_generators[i];
-			pipe_ctx->plane_res.mi = pool->mis[i];
-			pipe_ctx->plane_res.hubp = pool->hubps[i];
-			pipe_ctx->plane_res.ipp = pool->ipps[i];
-			pipe_ctx->plane_res.xfm = pool->transforms[i];
-			pipe_ctx->plane_res.dpp = pool->dpps[i];
-			pipe_ctx->stream_res.opp = pool->opps[i];
-			if (pool->dpps[i])
-				pipe_ctx->plane_res.mpcc_inst = pool->dpps[i]->inst;
-			pipe_ctx->pipe_idx = i;
-
-			if (i >= pool->timing_generator_count) {
-				int tg_inst = pool->timing_generator_count - 1;
-
-				pipe_ctx->stream_res.tg = pool->timing_generators[tg_inst];
-				pipe_ctx->stream_res.opp = pool->opps[tg_inst];
-			}
-
-			pipe_ctx->stream = stream;
-			return i;
-		}
-	}
-	return -1;
-}
-
 static struct hpo_dp_stream_encoder *find_first_free_match_hpo_dp_stream_enc_for_link(
 		struct resource_context *res_ctx,
 		const struct resource_pool *pool,
@@ -2770,6 +2794,7 @@ enum dc_status resource_map_pool_resources(
 	struct dc_context *dc_ctx = dc->ctx;
 	struct pipe_ctx *pipe_ctx = NULL;
 	int pipe_idx = -1;
+	bool acquired = false;
 
 	calculate_phy_pix_clks(stream);
 
@@ -2783,20 +2808,20 @@ enum dc_status resource_map_pool_resources(
 		if (pipe_idx < 0)
 			/* hw resource was assigned to other stream */
 			stream->apply_seamless_boot_optimization = false;
+		else
+			acquired = true;
 	}
 
-	if (pipe_idx < 0)
+	if (!acquired)
 		/* acquire new resources */
-		pipe_idx = acquire_first_free_pipe(&context->res_ctx, pool, stream);
+		acquired = acquire_otg_master_pipe_for_stream(
+				context, pool, stream);
 
-	if (pipe_idx < 0)
-		pipe_idx = acquire_first_split_pipe(&context->res_ctx, pool, stream);
+	pipe_ctx = resource_get_otg_master_for_stream(&context->res_ctx, stream);
 
-	if (pipe_idx < 0 || context->res_ctx.pipe_ctx[pipe_idx].stream_res.tg == NULL)
+	if (!pipe_ctx || pipe_ctx->stream_res.tg == NULL)
 		return DC_NO_CONTROLLER_RESOURCE;
 
-	pipe_ctx = &context->res_ctx.pipe_ctx[pipe_idx];
-
 	pipe_ctx->stream_res.stream_enc =
 		dc->res_pool->funcs->find_first_free_match_stream_enc_for_link(
 			&context->res_ctx, pool, stream);