tinyhal: audio: Impl channel adjustment for input sound flow

The issue is detected on RCAR3 platform where high level applications
can not capture a sound through Tinyhal with requested channel count
less than 8 (the min/max interval for allowed channel count values
is set to [8..8] in 'pcm3168a' driver, so pcm_open() function returns
error in case count != 8).
But only AUDIO_CHANNEL_IN_MONO & AUDIO_CHANNEL_IN_STEREO channel masks
are supported in alsa_device_profile.c file ('alsa_utils' directory).
So it is required to implement a patch which provides a channel
adjustment for input sound by converting the 8-channel flow
to requested Mono or Stereo flow.

Signed-off-by: Oleksandr Bobro <oleksandr.bobro@globallogic.com>

Author: AlexBobro

audio/audio_hw.c

@@ -48,6 +48,7 @@
 #endif
 
 #include <audio_utils/resampler.h>
+#include <audio_utils/channels.h>
 
 #include <tinyhal/audio_config.h>
 
@@ -1874,10 +1875,45 @@ static ssize_t do_in_pcm_read(struct audio_stream_in *stream, void *buffer,
         goto exit;
     }
 
-    if (in->resampler.resampler != NULL) {
-        ret = read_resampled_frames(in, buffer, frames_rq);
+    if (in->common.channel_count != in->hw_channel_count) {
+
+        ALOGV("do_in_pcm_read(): Read %d channel stream with adjustment (HW only supports %d channel reading)",
+              in->common.channel_count, in->hw_channel_count);
+
+        size_t read_buf_size = bytes * in->hw_channel_count / in->common.channel_count;
+        void *read_buffer = calloc(1, read_buf_size);
+        if (!read_buffer) {
+            ret = -1;
+            goto exit;
+        }
+
+        if (in->resampler.resampler != NULL) {
+            ret = read_resampled_frames(in, read_buffer, frames_rq);
+        } else {
+            ret = pcm_read(in->pcm, read_buffer, read_buf_size);
+        }
+
+        if (ret >= 0) {
+            bytes = adjust_channels(read_buffer, /* Input buffer */
+                                    in->hw_channel_count, /* Input channel count */
+                                    buffer, /* Output buffer */
+                                    in->common.channel_count, /* Output channel count */
+                                    in->common.frame_size / in->common.channel_count, /* Sample size */
+                                    read_buf_size /* Size of input buffer in bytes */
+                                   );
+            if (!bytes) {
+                ALOGE("do_in_pcm_read(): Failed to adjust channels");
+                ret = -1;
+            }
+        }
+        free(read_buffer);
+
     } else {
-        ret = pcm_read(in->pcm, buffer, bytes);
+        if (in->resampler.resampler != NULL) {
+            ret = read_resampled_frames(in, buffer, frames_rq);
+        } else {
+            ret = pcm_read(in->pcm, buffer, bytes);
+        }
     }
 
     /* Assume any non-negative return is a successful read */