drm/amd/display: Issue with 3 or more mcaches per surface

[Why & How]
Current logic in mcache admissibility check has flaw if
calculated number of maches are 3 or more per surface,
so sometimes the check may pass when it should fail,
and sometimes may fail when it should pass, fix the
issue and also adding additional check to make sure that
required number of mcaches per surface cannot be
higher than number of pipes + 1, used on that surface.
Reviewed-by: Chaitanya Dhere <chaitanya.dhere@amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Nevenko Stupar <nevenko.stupar@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dml2/dml21/src/dml2_top/dml_top_mcache.c

@@ -142,12 +142,12 @@ static unsigned int count_elements_in_span(int *array, unsigned int array_size,
 
 	while (span_start_index < array_size) {
 		for (i = span_start_index; i < array_size; i++) {
-			if (array[i] - span_start_value > span) {
+			if (array[i] - span_start_value <= span) {
 				if (i - span_start_index + 1 > greatest_element_count) {
 					greatest_element_count = i - span_start_index + 1;
 				}
+			} else
 				break;
-			}
 		}
 
 		span_start_index++;
@@ -207,9 +207,9 @@ bool dml2_top_mcache_validate_admissability(struct top_mcache_validate_admissabi
 	int temp, p0shift, p1shift;
 	unsigned int plane_index = 0;
 	unsigned int i;
-	char odm_combine_factor = 1;
-	char mpc_combine_factor = 1;
-	char num_dpps;
+	unsigned int odm_combine_factor;
+	unsigned int mpc_combine_factor;
+	unsigned int num_dpps;
 	unsigned int num_boundaries;
 	enum dml2_scaling_transform scaling_transform;
 	const struct dml2_plane_parameters *plane;
@@ -226,10 +226,10 @@ bool dml2_top_mcache_validate_admissability(struct top_mcache_validate_admissabi
 		plane = &params->display_cfg->plane_descriptors[plane_index];
 		stream = &params->display_cfg->stream_descriptors[plane->stream_index];
 
-		odm_combine_factor = (char)params->cfg_support_info->stream_support_info[plane->stream_index].odms_used;
+		num_dpps = odm_combine_factor = params->cfg_support_info->stream_support_info[plane->stream_index].odms_used;
 
 		if (odm_combine_factor == 1)
-			mpc_combine_factor = (char)params->cfg_support_info->plane_support_info[plane_index].dpps_used;
+			num_dpps = mpc_combine_factor = (unsigned int)params->cfg_support_info->plane_support_info[plane_index].dpps_used;
 		else
 			mpc_combine_factor = 1;
 
@@ -259,13 +259,13 @@ bool dml2_top_mcache_validate_admissability(struct top_mcache_validate_admissabi
 		// The last element in the unshifted boundary array will always be the first pixel outside the
 		// plane, which means theres no mcache associated with it, so -1
 		num_boundaries = params->mcache_allocations[plane_index].num_mcaches_plane0 == 0 ? 0 : params->mcache_allocations[plane_index].num_mcaches_plane0 - 1;
-		if (count_elements_in_span(params->mcache_allocations[plane_index].mcache_x_offsets_plane0,
-			num_boundaries, max_per_pipe_vp_p0) <= 1) {
+		if ((count_elements_in_span(params->mcache_allocations[plane_index].mcache_x_offsets_plane0,
+			num_boundaries, max_per_pipe_vp_p0) <= 1) && (num_boundaries <= num_dpps)) {
 			p0pass = true;
 		}
 		num_boundaries = params->mcache_allocations[plane_index].num_mcaches_plane1 == 0 ? 0 : params->mcache_allocations[plane_index].num_mcaches_plane1 - 1;
-		if (count_elements_in_span(params->mcache_allocations[plane_index].mcache_x_offsets_plane1,
-			num_boundaries, max_per_pipe_vp_p1) <= 1) {
+		if ((count_elements_in_span(params->mcache_allocations[plane_index].mcache_x_offsets_plane1,
+			num_boundaries, max_per_pipe_vp_p1) <= 1) && (num_boundaries <= num_dpps)) {
 			p1pass = true;
 		}