Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/sound/soc/sof/intel/hda-bus.c b/sound/soc/sof/intel/hda-bus.c
new file mode 100644
index 0000000..1d2babd
--- /dev/null
+++ b/sound/soc/sof/intel/hda-bus.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+//
+// This file is provided under a dual BSD/GPLv2 license.  When using or
+// redistributing this file, you may do so under either license.
+//
+// Copyright(c) 2018 Intel Corporation. All rights reserved.
+//
+// Authors: Keyon Jie <yang.jie@linux.intel.com>
+
+#include <linux/io.h>
+#include <sound/hdaudio.h>
+#include "../sof-priv.h"
+#include "hda.h"
+
+#if IS_ENABLED(CONFIG_SND_SOC_SOF_HDA_AUDIO_CODEC)
+#include "../../codecs/hdac_hda.h"
+#define sof_hda_ext_ops	snd_soc_hdac_hda_get_ops()
+#else
+#define sof_hda_ext_ops	NULL
+#endif
+
+/*
+ * This can be used for both with/without hda link support.
+ */
+void sof_hda_bus_init(struct hdac_bus *bus, struct device *dev)
+{
+#if IS_ENABLED(CONFIG_SND_SOC_SOF_HDA)
+	snd_hdac_ext_bus_init(bus, dev, NULL, sof_hda_ext_ops);
+#else /* CONFIG_SND_SOC_SOF_HDA */
+	memset(bus, 0, sizeof(*bus));
+	bus->dev = dev;
+
+	INIT_LIST_HEAD(&bus->stream_list);
+
+	bus->irq = -1;
+
+	/*
+	 * There is only one HDA bus atm. keep the index as 0.
+	 * Need to fix when there are more than one HDA bus.
+	 */
+	bus->idx = 0;
+
+	spin_lock_init(&bus->reg_lock);
+#endif /* CONFIG_SND_SOC_SOF_HDA */
+}