audio: kpb: fix buffer_stream_invalidate size in micselect copy helpers

In all four kpb_micselect_copy16/32 variants (HiFi3 and generic), the
call to buffer_stream_invalidate(source, size) used the output byte
count (produced_bytes) as the invalidation size. When in_channels >
micsel_channels, the actual input span read by the copy loop is:

  samples_per_chan * in_channels * sample_size

which is larger than the output span (size). Under-invalidating the
source buffer on CONFIG_INCOHERENT platforms can cause stale cache
reads.

Fix: compute samples_per_chan before the invalidate call and pass the
correct input span to buffer_stream_invalidate() in all four helpers.

Signed-off-by: Tomasz Leman <tomasz.m.leman@intel.com>

Author: tmleman

src/audio/kpb.c

@@ -1039,12 +1039,13 @@ static void kpb_micselect_copy16(struct comp_buffer *sink,
 	AE_SETCBEGIN0(audio_stream_get_addr(ostream));
 	AE_SETCEND0(audio_stream_get_end_addr(ostream));
 
-	buffer_stream_invalidate(source, size);
+	const size_t samples_per_chan = size / (sizeof(ae_int16) * micsel_channels);
+
+	buffer_stream_invalidate(source, samples_per_chan * in_channels * sizeof(ae_int16));
 	const ae_int16 *in_ptr = audio_stream_get_rptr(istream);
 	ae_int16x4 d16 = AE_ZERO16();
 	const size_t in_offset = in_channels * sizeof(ae_int16);
 	const size_t out_offset = micsel_channels * sizeof(ae_int16);
-	const size_t samples_per_chan = size / (sizeof(uint16_t) * micsel_channels);
 	ae_int16 *out_ptr;
 
 	for (ch = 0; ch < micsel_channels; ch++) {
@@ -1072,13 +1073,14 @@ static void kpb_micselect_copy32(struct comp_buffer *sink,
 	AE_SETCBEGIN0(audio_stream_get_addr(ostream));
 	AE_SETCEND0(audio_stream_get_end_addr(ostream));
 
-	buffer_stream_invalidate(source, size);
+	const size_t samples_per_chan = size / (sizeof(ae_int32) * micsel_channels);
+
+	buffer_stream_invalidate(source, samples_per_chan * in_channels * sizeof(ae_int32));
 
 	const ae_int32 *in_ptr = audio_stream_get_rptr(istream);
 	ae_int32x2 d32 = AE_ZERO32();
 	const size_t in_offset = in_channels * sizeof(ae_int32);
 	const size_t out_offset = micsel_channels * sizeof(ae_int32);
-	const size_t samples_per_chan = size / (sizeof(uint32_t) * micsel_channels);
 	ae_int32 *out_ptr;
 
 	for (ch = 0; ch < micsel_channels; ch++) {
@@ -1100,15 +1102,15 @@ static void kpb_micselect_copy16(struct comp_buffer *sink,
 {
 	struct audio_stream *istream = &source->stream;
 	struct audio_stream *ostream = &sink->stream;
-
-	buffer_stream_invalidate(source, size);
 	size_t out_samples;
 	uint32_t ch;
 
 	const int16_t *in_data;
 	int16_t *out_data;
 	const size_t samples_per_chan = size / (sizeof(uint16_t) * micsel_channels);
 
+	buffer_stream_invalidate(source, samples_per_chan * in_channels * sizeof(uint16_t));
+
 	for (ch = 0; ch < micsel_channels; ch++) {
 		out_samples = 0;
 		in_data = audio_stream_get_rptr(istream);
@@ -1132,14 +1134,14 @@ static void kpb_micselect_copy32(struct comp_buffer *sink,
 {
 	struct audio_stream *istream = &source->stream;
 	struct audio_stream *ostream = &sink->stream;
-
-	buffer_stream_invalidate(source, size);
 	size_t out_samples;
 	uint32_t ch;
 	const int32_t *in_data;
 	int32_t *out_data;
 	const size_t samples_per_chan = size / (sizeof(uint32_t) * micsel_channels);
 
+	buffer_stream_invalidate(source, samples_per_chan * in_channels * sizeof(uint32_t));
+
 	for (ch = 0; ch < micsel_channels; ch++) {
 		out_samples = 0;
 		in_data = audio_stream_get_rptr(istream);