drm/amd/display: Add debugfs interface for ODM combine info

[Why]
For use with IGT tests in userspace, the number of ODM segments in use
is required to be exposed to userspace to verify that ODM Combine is
working as expected when special timings are committed.

[How]
Add a connector specific debugfs entry that prints the number of ODM
segments in use.
Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1201,6 +1201,35 @@ static int internal_display_show(struct seq_file *m, void *data)
 	return 0;
 }
 
+/*
+ * Returns the number of segments used if ODM Combine mode is enabled.
+ * Example usage: cat /sys/kernel/debug/dri/0/DP-1/odm_combine_segments
+ */
+static int odm_combine_segments_show(struct seq_file *m, void *unused)
+{
+	struct drm_connector *connector = m->private;
+	struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
+	struct dc_link *link = aconnector->dc_link;
+	struct pipe_ctx *pipe_ctx = NULL;
+	int i, segments = 0;
+
+	for (i = 0; i < MAX_PIPES; i++) {
+		pipe_ctx = &link->dc->current_state->res_ctx.pipe_ctx[i];
+		if (pipe_ctx->stream &&
+		    pipe_ctx->stream->link == link)
+			break;
+	}
+
+	if (connector->status != connector_status_connected)
+		return -ENODEV;
+
+	if (pipe_ctx != NULL && pipe_ctx->stream_res.tg->funcs->get_odm_combine_segments)
+		pipe_ctx->stream_res.tg->funcs->get_odm_combine_segments(pipe_ctx->stream_res.tg, &segments);
+
+	seq_printf(m, "%d\n", segments);
+	return 0;
+}
+
 /* function description
  *
  * generic SDP message access for testing
@@ -2713,6 +2742,7 @@ DEFINE_SHOW_ATTRIBUTE(dmub_tracebuffer);
 DEFINE_SHOW_ATTRIBUTE(dp_lttpr_status);
 DEFINE_SHOW_ATTRIBUTE(hdcp_sink_capability);
 DEFINE_SHOW_ATTRIBUTE(internal_display);
+DEFINE_SHOW_ATTRIBUTE(odm_combine_segments);
 DEFINE_SHOW_ATTRIBUTE(psr_capability);
 DEFINE_SHOW_ATTRIBUTE(dp_is_mst_connector);
 DEFINE_SHOW_ATTRIBUTE(dp_mst_progress_status);
@@ -2991,7 +3021,8 @@ static const struct {
 } connector_debugfs_entries[] = {
 		{"force_yuv420_output", &force_yuv420_output_fops},
 		{"trigger_hotplug", &trigger_hotplug_debugfs_fops},
-		{"internal_display", &internal_display_fops}
+		{"internal_display", &internal_display_fops},
+		{"odm_combine_segments", &odm_combine_segments_fops}
 };
 
 /*

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_optc.c

@@ -98,6 +98,30 @@ static void optc32_set_odm_combine(struct timing_generator *optc, int *opp_id, i
 	optc1->opp_count = opp_cnt;
 }
 
+void optc32_get_odm_combine_segments(struct timing_generator *tg, int *odm_combine_segments)
+{
+	struct optc *optc1 = DCN10TG_FROM_TG(tg);
+	int segments;
+
+	REG_GET(OPTC_DATA_SOURCE_SELECT, OPTC_NUM_OF_INPUT_SEGMENT, &segments);
+
+	switch (segments) {
+	case 0:
+		*odm_combine_segments = 1;
+		break;
+	case 1:
+		*odm_combine_segments = 2;
+		break;
+	case 3:
+		*odm_combine_segments = 4;
+		break;
+	/* 2 is reserved */
+	case 2:
+	default:
+		*odm_combine_segments = -1;
+	}
+}
+
 void optc32_set_h_timing_div_manual_mode(struct timing_generator *optc, bool manual_mode)
 {
 	struct optc *optc1 = DCN10TG_FROM_TG(optc);
@@ -303,6 +327,7 @@ static struct timing_generator_funcs dcn32_tg_funcs = {
 		.set_dwb_source = NULL,
 		.set_odm_bypass = optc32_set_odm_bypass,
 		.set_odm_combine = optc32_set_odm_combine,
+		.get_odm_combine_segments = optc32_get_odm_combine_segments,
 		.set_h_timing_div_manual_mode = optc32_set_h_timing_div_manual_mode,
 		.get_optc_source = optc2_get_optc_source,
 		.set_out_mux = optc3_set_out_mux,

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_optc.h

@@ -180,5 +180,6 @@
 
 void dcn32_timing_generator_init(struct optc *optc1);
 void optc32_set_h_timing_div_manual_mode(struct timing_generator *optc, bool manual_mode);
+void optc32_get_odm_combine_segments(struct timing_generator *tg, int *odm_combine_segments);
 
 #endif /* __DC_OPTC_DCN32_H__ */

drivers/gpu/drm/amd/display/dc/inc/hw/timing_generator.h

@@ -309,6 +309,7 @@ struct timing_generator_funcs {
 	 */
 	void (*set_odm_combine)(struct timing_generator *optc, int *opp_id, int opp_cnt,
 			struct dc_crtc_timing *timing);
+	void (*get_odm_combine_segments)(struct timing_generator *tg, int *odm_segments);
 	void (*set_h_timing_div_manual_mode)(struct timing_generator *optc, bool manual_mode);
 	void (*set_gsl)(struct timing_generator *optc, const struct gsl_params *params);
 	void (*set_gsl_source_select)(struct timing_generator *optc,