drivers: usb: uhc: mcux: Fix nocache buffer allocation for IN/OUT transfer

Use net_buf_tail() instead of __buf for proper buffer positioning.
Add null check and error handling for nocache buffer allocation.
Only copy data for OUT transfers during buffer setup.

Signed-off-by: Mark Wang <[email protected]>

Author: MarkWangChinese

drivers/usb/uhc/uhc_mcux_ehci.c

@@ -171,7 +171,7 @@ static void uhc_mcux_transfer_callback(void *param, usb_host_transfer_t *transfe
 	if ((xfer->buf != NULL) && (transfer->transferBuffer != NULL) &&
 	    USB_EP_DIR_IS_IN(xfer->ep) && (transfer->transferSofar > 0)) {
 #if defined(CONFIG_NOCACHE_MEMORY)
-		memcpy(xfer->buf->__buf, transfer->transferBuffer, transfer->transferSofar);
+		memcpy(net_buf_tail(xfer->buf), transfer->transferBuffer, transfer->transferSofar);
 #endif
 		net_buf_add(xfer->buf, transfer->transferSofar);
 #if defined(CONFIG_NOCACHE_MEMORY)
@@ -199,8 +199,20 @@ static usb_host_transfer_t *uhc_mcux_hal_init_transfer(const struct device *dev,
 #if defined(CONFIG_NOCACHE_MEMORY)
 	mcux_xfer->setupPacket = uhc_mcux_nocache_alloc(8u);
 	memcpy(mcux_xfer->setupPacket, xfer->setup_pkt, 8u);
-	if (xfer->buf != NULL) {
-		mcux_xfer->transferBuffer = uhc_mcux_nocache_alloc(mcux_xfer->transferLength);
+
+	if (mcux_xfer->transferBuffer != NULL && mcux_xfer->transferLength != 0) {
+		uint8_t *nocache_buf = uhc_mcux_nocache_alloc(mcux_xfer->transferLength);
+
+		if (nocache_buf == NULL) {
+			k_mem_slab_free(&mcux_uhc_transfer_pool, mcux_xfer);
+			return NULL;
+		}
+
+		if (USB_EP_DIR_IS_OUT(xfer->ep)) {
+			memcpy(nocache_buf, mcux_xfer->transferBuffer, mcux_xfer->transferLength);
+		}
+
+		mcux_xfer->transferBuffer = nocache_buf;
 	}
 #endif