hal: add support for ull audio playback

Add a new use case and mixer paths to support ultra
low latency audio playback. This use case exercises the
ULL mode in the DSP.

Bug: 10546170

Change-Id: I6685dd0f346072029ca51e4ce92856a13e74ee76
diff --git a/hal/audio_hw.c b/hal/audio_hw.c
index b307f6c..486ce8f 100644
--- a/hal/audio_hw.c
+++ b/hal/audio_hw.c
@@ -155,6 +155,7 @@
     [USECASE_AUDIO_PLAYBACK_MULTI_CH] = "multi-channel-playback",
     [USECASE_AUDIO_PLAYBACK_OFFLOAD] = "compress-offload-playback",
     [USECASE_AUDIO_PLAYBACK_TTS] = "audio-tts-playback",
+    [USECASE_AUDIO_PLAYBACK_ULL] = "audio-ull-playback",
 
     [USECASE_AUDIO_RECORD] = "audio-record",
     [USECASE_AUDIO_RECORD_LOW_LATENCY] = "low-latency-record",
@@ -2172,6 +2173,9 @@
         } else if (out->flags & AUDIO_OUTPUT_FLAG_TTS) {
             out->usecase = USECASE_AUDIO_PLAYBACK_TTS;
             out->config = pcm_config_deep_buffer;
+        } else if (out->flags & AUDIO_OUTPUT_FLAG_RAW) {
+            out->usecase = USECASE_AUDIO_PLAYBACK_ULL;
+            out->config = pcm_config_low_latency;
         } else {
             out->usecase = USECASE_AUDIO_PLAYBACK_LOW_LATENCY;
             out->config = pcm_config_low_latency;