diff --git a/topology/sof-apl-nocodec.m4 b/topology/sof-apl-nocodec.m4
index 1582c20..2b2b839 100644
--- a/topology/sof-apl-nocodec.m4
+++ b/topology/sof-apl-nocodec.m4
@@ -36,6 +36,11 @@ include(`platform/intel/dmic.m4')
 # PCM6 <---- volume <----- DMIC6 (DMIC01)
 #
 
+dnl PIPELINE_PCM_DAI_ADD(pipeline,
+dnl     pipe id, pcm, max channels, format,
+dnl     frames, deadline, priority, core,
+dnl     dai type, dai_index, dai format, periods)
+
 # Low Latency playback pipeline 1 on PCM 0 using max 2 channels of s16le.
 # Schedule 48 frames per 1000us deadline on core 0 with priority 0
 PIPELINE_PCM_DAI_ADD(sof/pipe-volume-playback.m4,
@@ -119,6 +124,11 @@ PIPELINE_PCM_DAI_ADD(sof/pipe-passthrough-capture.m4,
 # DAIs configuration
 #
 
+dnl DAI_ADD(pipeline,
+dnl     pipe id, dai type, dai_index, dai_be,
+dnl     buffer, periods, format,
+dnl     frames, deadline, priority, core)
+
 # playback DAI is SSP0 using 2 periods
 # Buffers use s16le format, with 48 frame per 1000us on core 0 with priority 0
 DAI_ADD(sof/pipe-dai-playback.m4,
@@ -211,23 +221,28 @@ DAI_ADD(sof/pipe-dai-capture.m4,
 	48, 1000, 0, 0)
 
 # PCM Low Latency, id 0
+dnl PCM_DUPLEX_ADD(name, pipeline, pcm_id, dai_id, playback, capture)
 PCM_DUPLEX_ADD(Port0, 0, 0, 0, PIPELINE_PCM_1, PIPELINE_PCM_2)
 PCM_DUPLEX_ADD(Port1, 1, 1, 1, PIPELINE_PCM_3, PIPELINE_PCM_4)
 PCM_DUPLEX_ADD(Port2, 2, 2, 2, PIPELINE_PCM_5, PIPELINE_PCM_6)
 PCM_DUPLEX_ADD(Port3, 3, 3, 3, PIPELINE_PCM_7, PIPELINE_PCM_8)
 PCM_DUPLEX_ADD(Port4, 4, 4, 4, PIPELINE_PCM_9, PIPELINE_PCM_10)
 PCM_DUPLEX_ADD(Port5, 5, 5, 5, PIPELINE_PCM_11, PIPELINE_PCM_12)
+dnl PCM_CAPTURE_ADD(name, pipeline, pcm_id, dai_id, capture)
 PCM_CAPTURE_ADD(DMIC01, 6, 6, 6, PIPELINE_PCM_13)
 
 #
 # BE configurations - overrides config in ACPI if present
 #
 
+dnl DAI_CONFIG(type, dai_index, link_id, name, ssp_config/dmic_config)
 DAI_CONFIG(SSP, 0, 0, NoCodec-0,
+	   dnl SSP_CONFIG(format, mclk, bclk, fsync, tdm, ssp_config_data)
 	   SSP_CONFIG(I2S, SSP_CLOCK(mclk, 24576000, codec_mclk_in),
 		      SSP_CLOCK(bclk, 1536000, codec_slave),
 		      SSP_CLOCK(fsync, 48000, codec_slave),
 		      SSP_TDM(2, 16, 3, 3),
+		      dnl SSP_CONFIG_DATA(type, dai_index, valid bits, mclk_id)
 		      SSP_CONFIG_DATA(SSP, 0, 16)))
 
 DAI_CONFIG(SSP, 1, 1, NoCodec-1,
@@ -266,7 +281,13 @@ DAI_CONFIG(SSP, 5, 5, NoCodec-5,
 		      SSP_CONFIG_DATA(SSP, 5, 16)))
 
 DAI_CONFIG(DMIC, 0, 6, NoCodec-6,
+	   dnl DMIC_CONFIG(driver_version, clk_min, clk_mac, duty_min, duty_max,
+	   dnl		   sample_rate,
+	   dnl		   fifo word length, type, dai_index, pdm controller config)
 	   DMIC_CONFIG(1, 500000, 4800000, 40, 60, 48000,
+		dnl DMIC_WORD_LENGTH(frame_format)
 		DMIC_WORD_LENGTH(s32le), DMIC, 0,
+		dnl PDM_CONFIG(type, dai_index, num pdm active, pdm tuples list)
+		dnl STEREO_PDM0 is a pre-defined pdm config for stereo capture
 		PDM_CONFIG(DMIC, 0, STEREO_PDM0)))