[PATCH 40/43] drm/amd/display: Add code comments clock and encode code

[<Roman.Li@amd.com>]

From: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>

This commit adds some comments to make easier to understand the clock
update for DCN 201, the encode function, and other minor comments.

Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
---
 .../amd/display/dc/clk_mgr/dcn201/dcn201_clk_mgr.c    | 11 +++++++++++
 drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hubbub.c |  2 +-
 .../display/dc/dcn31/dcn31_hpo_dp_stream_encoder.c    |  4 ++++
 drivers/gpu/drm/amd/display/dc/resource/Makefile      |  6 ------
 4 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn201/dcn201_clk_mgr.c b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn201/dcn201_clk_mgr.c
index 9c90090e7351..f77840dd051e 100644
--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn201/dcn201_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dcn201/dcn201_clk_mgr.c
@@ -100,7 +100,15 @@ static void dcn201_update_clocks(struct clk_mgr *clk_mgr_base,
 
 	if (clk_mgr_base->clks.dispclk_khz == 0 ||
 	    dc->debug.force_clock_mode & 0x1) {
+		/* this is from resume or boot up, if forced_clock cfg option
+		 * used, we bypass program dispclk and DPPCLK, but need set them
+		 * for S3.
+		 */
+
 		force_reset = true;
+		/* force_clock_mode 0x1:  force reset the clock even it is the
+		 * same clock as long as it is in Passive level.
+		 */
 
 		dcn2_read_clocks_from_hw_dentist(clk_mgr_base);
 	}
@@ -150,11 +158,14 @@ static void dcn201_update_clocks(struct clk_mgr *clk_mgr_base,
 
 	if (dc->config.forced_clocks == false || (force_reset && safe_to_lower)) {
 		if (dpp_clock_lowered) {
+			// if clock is being lowered, increase DTO before lowering refclk
 			dcn20_update_clocks_update_dpp_dto(clk_mgr, context, safe_to_lower);
 			dcn20_update_clocks_update_dentist(clk_mgr, context);
 		} else {
+			// if clock is being raised, increase refclk before lowering DTO
 			if (update_dppclk || update_dispclk)
 				dcn20_update_clocks_update_dentist(clk_mgr, context);
+			// always update dtos unless clock is lowered and not safe to lower
 			dcn20_update_clocks_update_dpp_dto(clk_mgr, context, safe_to_lower);
 		}
 	}
diff --git a/drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hubbub.c b/drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hubbub.c
index 09ea65acb2c4..63798132ed95 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hubbub.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn201/dcn201_hubbub.c
@@ -103,5 +103,5 @@ void hubbub201_construct(struct dcn20_hubbub *hubbub,
 	hubbub->masks = hubbub_mask;
 
 	hubbub->debug_test_index_pstate = 0xB;
-	hubbub->detile_buf_size = 164 * 1024;
+	hubbub->detile_buf_size = 164 * 1024; /* 164KB for DCN2.0 */
 }
diff --git a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_hpo_dp_stream_encoder.c b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_hpo_dp_stream_encoder.c
index 45143459eedd..678db949cfe3 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_hpo_dp_stream_encoder.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn31/dcn31_hpo_dp_stream_encoder.c
@@ -474,6 +474,10 @@ static void dcn31_hpo_dp_stream_enc_update_dp_info_packets(
 				&info_frame->hdrsmd,
 				true);
 
+	/* packetIndex 4 is used for send immediate sdp message, and please
+	 * use other packetIndex (such as 5,6) for other info packet
+	 */
+
 	if (info_frame->adaptive_sync.valid)
 		enc->vpg->funcs->update_generic_info_packet(
 				enc->vpg,
diff --git a/drivers/gpu/drm/amd/display/dc/resource/Makefile b/drivers/gpu/drm/amd/display/dc/resource/Makefile
index 184b1f23aa77..db9048974d74 100644
--- a/drivers/gpu/drm/amd/display/dc/resource/Makefile
+++ b/drivers/gpu/drm/amd/display/dc/resource/Makefile
@@ -102,10 +102,6 @@ AMD_DISPLAY_FILES += $(AMD_DAL_RESOURCE_DCN21)
 
 ###############################################################################
 
-###############################################################################
-
-###############################################################################
-
 RESOURCE_DCN30 = dcn30_resource.o
 
 AMD_DAL_RESOURCE_DCN30 = $(addprefix $(AMDDALPATH)/dc/resource/dcn30/,$(RESOURCE_DCN30))
@@ -202,6 +198,4 @@ AMD_DISPLAY_FILES += $(AMD_DAL_RESOURCE_DCN351)
 
 ###############################################################################
 
-###############################################################################
-
 endif
-- 
2.34.1