drm/amd/display: add delay between panel pwr off to on.

As per eDP 1.4 spec, there must be at least 500ms delay
between eDP power off and on.
This change added time stamp when edp power off, which can
be used to calculate duration time when edp power on.
If duration less than 500ms, add a wait.
Signed-off-by: Charlene Liu <charlene.liu@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_services.c

@@ -43,6 +43,13 @@ unsigned long long dm_get_timestamp(struct dc_context *ctx)
 	return timespec64_to_ns(&time);
 }
 
+unsigned long long dm_get_elapse_time_in_ns(struct dc_context *ctx,
+		unsigned long long current_time_stamp,
+		unsigned long long last_time_stamp)
+{
+	return current_time_stamp - last_time_stamp;
+}
+
 void dm_perf_trace_timestamp(const char *func_name, unsigned int line)
 {
 }

drivers/gpu/drm/amd/display/dc/dc_link.h

@@ -51,6 +51,14 @@ struct link_mst_stream_allocation_table {
 	struct link_mst_stream_allocation stream_allocations[MAX_CONTROLLER_NUM];
 };
 
+struct time_stamp {
+	uint64_t edp_poweroff;
+	uint64_t edp_poweron;
+};
+
+struct link_trace {
+	struct time_stamp time_stamp;
+};
 /*
  * A link contains one or more sinks and their connected status.
  * The currently active signal type (HDMI, DP-SST, DP-MST) is also reported.
@@ -114,6 +122,7 @@ struct dc_link {
 
 	struct dc_link_status link_status;
 
+	struct link_trace link_trace;
 };
 
 const struct dc_link_status *dc_link_get_status(const struct dc_link *dc_link);

drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c

@@ -849,6 +849,28 @@ void hwss_edp_power_control(
 
 	if (power_up != is_panel_powered_on(hwseq)) {
 		/* Send VBIOS command to prompt eDP panel power */
+		if (power_up) {
+			unsigned long long current_ts = dm_get_timestamp(ctx);
+			unsigned long long duration_in_ms =
+					dm_get_elapse_time_in_ns(
+							ctx,
+							current_ts,
+							link->link_trace.time_stamp.edp_poweroff) / 1000000;
+			unsigned long long wait_time_ms = 0;
+
+			/* max 500ms from LCDVDD off to on */
+			if (link->link_trace.time_stamp.edp_poweroff == 0)
+				wait_time_ms = 500;
+			else if (duration_in_ms < 500)
+				wait_time_ms = 500 - duration_in_ms;
+
+			if (wait_time_ms) {
+				msleep(wait_time_ms);
+				dm_output_to_console("%s: wait %lld ms to power on eDP.\n",
+						__func__, wait_time_ms);
+			}
+
+		}
 
 		DC_LOG_HW_RESUME_S3(
 				"%s: Panel Power action: %s\n",
@@ -862,9 +884,14 @@ void hwss_edp_power_control(
 		cntl.coherent = false;
 		cntl.lanes_number = LANE_COUNT_FOUR;
 		cntl.hpd_sel = link->link_enc->hpd_source;
-
 		bp_result = link_transmitter_control(ctx->dc_bios, &cntl);
 
+		if (!power_up)
+			/*save driver power off time stamp*/
+			link->link_trace.time_stamp.edp_poweroff = dm_get_timestamp(ctx);
+		else
+			link->link_trace.time_stamp.edp_poweron = dm_get_timestamp(ctx);
+
 		if (bp_result != BP_RESULT_OK)
 			DC_LOG_ERROR(
 					"%s: Panel Power bp_result: %d\n",

drivers/gpu/drm/amd/display/dc/dm_services.h

@@ -341,6 +341,10 @@ bool dm_dmcu_set_pipe(struct dc_context *ctx, unsigned int controller_id);
 
 unsigned long long dm_get_timestamp(struct dc_context *ctx);
 
+unsigned long long dm_get_elapse_time_in_ns(struct dc_context *ctx,
+		unsigned long long current_time_stamp,
+		unsigned long long last_time_stamp);
+
 /*
  * performance tracing
  */