Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/greybus/connection.h b/include/linux/greybus/connection.h
new file mode 100644
index 0000000..d59b7fc
--- /dev/null
+++ b/include/linux/greybus/connection.h
@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Greybus connections
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ */
+
+#ifndef __CONNECTION_H
+#define __CONNECTION_H
+
+#include <linux/bits.h>
+#include <linux/list.h>
+#include <linux/kfifo.h>
+#include <linux/kref.h>
+#include <linux/workqueue.h>
+
+#define GB_CONNECTION_FLAG_CSD		BIT(0)
+#define GB_CONNECTION_FLAG_NO_FLOWCTRL	BIT(1)
+#define GB_CONNECTION_FLAG_OFFLOADED	BIT(2)
+#define GB_CONNECTION_FLAG_CDSI1	BIT(3)
+#define GB_CONNECTION_FLAG_CONTROL	BIT(4)
+#define GB_CONNECTION_FLAG_HIGH_PRIO	BIT(5)
+
+#define GB_CONNECTION_FLAG_CORE_MASK	GB_CONNECTION_FLAG_CONTROL
+
+enum gb_connection_state {
+	GB_CONNECTION_STATE_DISABLED		= 0,
+	GB_CONNECTION_STATE_ENABLED_TX		= 1,
+	GB_CONNECTION_STATE_ENABLED		= 2,
+	GB_CONNECTION_STATE_DISCONNECTING	= 3,
+};
+
+struct gb_operation;
+
+typedef int (*gb_request_handler_t)(struct gb_operation *);
+
+struct gb_connection {
+	struct gb_host_device		*hd;
+	struct gb_interface		*intf;
+	struct gb_bundle		*bundle;
+	struct kref			kref;
+	u16				hd_cport_id;
+	u16				intf_cport_id;
+
+	struct list_head		hd_links;
+	struct list_head		bundle_links;
+
+	gb_request_handler_t		handler;
+	unsigned long			flags;
+
+	struct mutex			mutex;
+	spinlock_t			lock;
+	enum gb_connection_state	state;
+	struct list_head		operations;
+
+	char				name[16];
+	struct workqueue_struct		*wq;
+
+	atomic_t			op_cycle;
+
+	void				*private;
+
+	bool				mode_switch;
+};
+
+struct gb_connection *gb_connection_create_static(struct gb_host_device *hd,
+				u16 hd_cport_id, gb_request_handler_t handler);
+struct gb_connection *gb_connection_create_control(struct gb_interface *intf);
+struct gb_connection *gb_connection_create(struct gb_bundle *bundle,
+				u16 cport_id, gb_request_handler_t handler);
+struct gb_connection *gb_connection_create_flags(struct gb_bundle *bundle,
+				u16 cport_id, gb_request_handler_t handler,
+				unsigned long flags);
+struct gb_connection *gb_connection_create_offloaded(struct gb_bundle *bundle,
+				u16 cport_id, unsigned long flags);
+void gb_connection_destroy(struct gb_connection *connection);
+
+static inline bool gb_connection_is_static(struct gb_connection *connection)
+{
+	return !connection->intf;
+}
+
+int gb_connection_enable(struct gb_connection *connection);
+int gb_connection_enable_tx(struct gb_connection *connection);
+void gb_connection_disable_rx(struct gb_connection *connection);
+void gb_connection_disable(struct gb_connection *connection);
+void gb_connection_disable_forced(struct gb_connection *connection);
+
+void gb_connection_mode_switch_prepare(struct gb_connection *connection);
+void gb_connection_mode_switch_complete(struct gb_connection *connection);
+
+void greybus_data_rcvd(struct gb_host_device *hd, u16 cport_id,
+		       u8 *data, size_t length);
+
+void gb_connection_latency_tag_enable(struct gb_connection *connection);
+void gb_connection_latency_tag_disable(struct gb_connection *connection);
+
+static inline bool gb_connection_e2efc_enabled(struct gb_connection *connection)
+{
+	return !(connection->flags & GB_CONNECTION_FLAG_CSD);
+}
+
+static inline bool
+gb_connection_flow_control_disabled(struct gb_connection *connection)
+{
+	return connection->flags & GB_CONNECTION_FLAG_NO_FLOWCTRL;
+}
+
+static inline bool gb_connection_is_offloaded(struct gb_connection *connection)
+{
+	return connection->flags & GB_CONNECTION_FLAG_OFFLOADED;
+}
+
+static inline bool gb_connection_is_control(struct gb_connection *connection)
+{
+	return connection->flags & GB_CONNECTION_FLAG_CONTROL;
+}
+
+static inline void *gb_connection_get_data(struct gb_connection *connection)
+{
+	return connection->private;
+}
+
+static inline void gb_connection_set_data(struct gb_connection *connection,
+					  void *data)
+{
+	connection->private = data;
+}
+
+#endif /* __CONNECTION_H */