samples: usb: uac2: Leave cache management up to drivers

Do not call cache management functions in sample because it does not
work properly if driver uses bounce buffers.

Signed-off-by: Tomasz Moń <[email protected]>

Author: tmon-nordic

samples/subsys/usb/uac2_explicit_feedback/src/main.c

@@ -10,7 +10,6 @@
 #include <sample_usbd.h>
 #include "feedback.h"
 
-#include <zephyr/cache.h>
 #include <zephyr/device.h>
 #include <zephyr/usb/usbd.h>
 #include <zephyr/usb/class/usbd_uac2.h>
@@ -117,7 +116,6 @@ static void uac2_data_recv_cb(const struct device *dev, uint8_t terminal,
 		 */
 		size = BLOCK_SIZE;
 		memset(buf, 0, size);
-		sys_cache_data_flush_range(buf, size);
 	}
 
 	LOG_DBG("Received %d data to input terminal %d", size, terminal);

samples/subsys/usb/uac2_implicit_feedback/src/main.c

@@ -10,7 +10,6 @@
 #include <sample_usbd.h>
 #include "feedback.h"
 
-#include <zephyr/cache.h>
 #include <zephyr/device.h>
 #include <zephyr/usb/usbd.h>
 #include <zephyr/usb/class/usbd_uac2.h>
@@ -164,7 +163,6 @@ static void uac2_data_recv_cb(const struct device *dev, uint8_t terminal,
 			size = SAMPLES_PER_SOF * BYTES_PER_SLOT;
 		}
 		memset(buf, 0, size);
-		sys_cache_data_flush_range(buf, size);
 	}
 
 	LOG_DBG("Received %d data to input terminal %d", size, terminal);
@@ -259,7 +257,6 @@ static void process_mic_data(const struct device *dev, struct usb_i2s_ctx *ctx)
 			/* No data available, I2S will restart soon */
 			return;
 		}
-		sys_cache_data_invd_range(rx_block, num_bytes);
 
 		/* I2S operates on 2 channels (stereo) */
 		rx_samples = num_bytes / (BYTES_PER_SAMPLE * 2);
@@ -314,7 +311,6 @@ static void process_mic_data(const struct device *dev, struct usb_i2s_ctx *ctx)
 			ctx->pending_mic_samples = mic_samples;
 			return;
 		}
-		sys_cache_data_invd_range(rx_block, num_bytes);
 
 		src = rx_block;
 		rx_samples = num_bytes / (BYTES_PER_SAMPLE * 2);
@@ -424,7 +420,6 @@ static void process_mic_data(const struct device *dev, struct usb_i2s_ctx *ctx)
 	}
 
 	/* Finally send the microphone samples to host */
-	sys_cache_data_flush_range(mic_buf, mic_samples * BYTES_PER_SAMPLE);
 	if (usbd_uac2_send(dev, MICROPHONE_IN_TERMINAL_ID,
 			   mic_buf, mic_samples * BYTES_PER_SAMPLE) < 0) {
 		k_mem_slab_free(&i2s_rx_slab, mic_buf);