Audio: Volume: Set align constraints for source only

This patch modifies the frame align request to match the
gain loop samples unroll number. In HiFi5 four s32 samples or
eight s16 are processed per iteration. In HiFi3, HiFi4 and
generic C two s32 samples or four s16 samples are processed
per iteration. The equation

	frame_align_req = n / gcd(n, channels)

with
	n = 8 or n = 4 for HiFi5 for s16 or s32
	n = 4 or 4 = 2 for other builds for s16 or s32

ensures that every aligned frame count is multiple of gain
loop unroll amount.

The equation for byte_align is same as earlier but the unnecessary
SOF_USE_HIFI() are removed. The code wasn't wrong for HiFi5 but
it was confusing. The check for 6ch wasn't done because the
SOF_FRAME_BYTE_ALIGN value was the same as
VOLUME_HIFI3_HIFI4_FRAME_BYTE_ALIGN_6CH.

Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>

Author: singalsu

src/audio/volume/volume.c

@@ -639,30 +639,37 @@ static vol_zc_func vol_get_zc_function(struct comp_dev *dev,
 /**
  * \brief Set volume frames alignment limit.
  * \param[in,out] source Structure pointer of source.
- * \param[in,out] sink Structure pointer of sink.
  */
-static void volume_set_alignment(struct audio_stream *source,
-				 struct audio_stream *sink)
+static void volume_set_alignment(struct audio_stream *source)
 {
-	/* Both source and sink buffer in HiFi5  processing version,
-	 * xtensa intrinsics ask for 16-byte aligned.
+	const int channels = audio_stream_get_channels(source);
+
+	/* The source buffer in HiFi5 processing version needs 16 bytes alignment. The
+	 * macro SOF_FRAME_BYTE_ALIGN is set in common.h to the requirement align.
+	 * The VOLUME_HIFI3_HIFI4_FRAME_BYTE_ALIGN_6CH also has the value 16 and the
+	 * same align for 5.1 channels works for HiFi5 too.
 	 *
-	 * Both source and sink buffer in HiFi3 or HiFi4 processing version,
-	 * xtensa intrinsics ask for 8-byte aligned. 5.1 format SSE audio
-	 * requires 16-byte aligned.
+	 * In HiFi4 processing version the source align requirement is 8 bytes. While
+	 * the 5.1 format SSE audio requires 16 bytes alignment.
+	 */
+	const uint32_t byte_align =
+		(channels == 6) ? VOLUME_HIFI3_HIFI4_FRAME_BYTE_ALIGN_6CH : SOF_FRAME_BYTE_ALIGN;
+
+	/* On HiFi5 the number of samples to process must be multiple of four for s24/s32
+	 * and multiple of eight for s16. For HiFi4 and HiFi3 the number of samples
+	 * need to be multiple of two for s32 and multiple of four for s16.
+	 * E.g. for s32 format for channels counts of 1, 2, 4, 6, ... the
+	 * frame align need to be 4, 2, 1, 2, ...
 	 */
-#if SOF_USE_HIFI(3, VOLUME) || SOF_USE_HIFI(4, VOLUME)
-	const uint32_t byte_align = audio_stream_get_channels(source) == 6 ?
-		VOLUME_HIFI3_HIFI4_FRAME_BYTE_ALIGN_6CH : SOF_FRAME_BYTE_ALIGN;
+#if SOF_USE_HIFI(5, VOLUME)
+	const int n = (audio_stream_get_valid_fmt(source) == SOF_IPC_FRAME_S16_LE) ? 8 : 4;
 #else
-	const uint32_t byte_align = SOF_FRAME_BYTE_ALIGN;
+	const int n = (audio_stream_get_valid_fmt(source) == SOF_IPC_FRAME_S16_LE) ? 4 : 2;
 #endif
 
-	/*There is no limit for frame number, so both source and sink set it to be 1*/
-	const uint32_t frame_align_req = 1;
+	const uint32_t frame_align_req = (uint32_t)(n / gcd(n, channels));
 
 	audio_stream_set_align(byte_align, frame_align_req, source);
-	audio_stream_set_align(byte_align, frame_align_req, sink);
 }
 
 /**
@@ -698,7 +705,7 @@ static int volume_prepare(struct processing_module *mod,
 
 	ret = volume_peak_prepare(cd, mod);
 
-	volume_set_alignment(&sourceb->stream, &sinkb->stream);
+	volume_set_alignment(&sourceb->stream);
 
 	/* get sink period bytes */
 	sink_period_bytes = audio_stream_period_bytes(&sinkb->stream,