2 files changed, 103 insertions, 1 deletions
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index 6e38fb9d2117..d8c4e9f73839 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -237,7 +237,7 @@ struct usb_function {
 	/* internals */
 	struct list_head		list;
 	DECLARE_BITMAP(endpoints, 32);
-	const struct usb_function_instance *fi;
+	struct usb_function_instance *fi;
 
 	unsigned int		bind_deactivated:1;
 };
diff --git a/include/linux/usb/xhci-sideband.h b/include/linux/usb/xhci-sideband.h
new file mode 100644
index 000000000000..45288c392f6e
--- /dev/null
+++ b/include/linux/usb/xhci-sideband.h
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * xHCI host controller sideband support
+ *
+ * Copyright (c) 2023-2025, Intel Corporation.
+ *
+ * Author: Mathias Nyman <mathias.nyman@linux.intel.com>
+ */
+#ifndef __LINUX_XHCI_SIDEBAND_H
+#define __LINUX_XHCI_SIDEBAND_H
+
+#include <linux/scatterlist.h>
+#include <linux/usb.h>
+
+#define	EP_CTX_PER_DEV		31	/* FIXME defined twice, from xhci.h */
+
+struct xhci_sideband;
+
+enum xhci_sideband_type {
+	XHCI_SIDEBAND_AUDIO,
+	XHCI_SIDEBAND_VENDOR,
+};
+
+enum xhci_sideband_notify_type {
+	XHCI_SIDEBAND_XFER_RING_FREE,
+};
+
+/**
+ * struct xhci_sideband_event - sideband event
+ * @type: notifier type
+ * @evt_data: event data
+ */
+struct xhci_sideband_event {
+	enum xhci_sideband_notify_type type;
+	void *evt_data;
+};
+
+/**
+ * struct xhci_sideband - representation of a sideband accessed usb device.
+ * @xhci: The xhci host controller the usb device is connected to
+ * @vdev: the usb device accessed via sideband
+ * @eps: array of endpoints controlled via sideband
+ * @ir: event handling and buffer for sideband accessed device
+ * @type: xHCI sideband type
+ * @mutex: mutex for sideband operations
+ * @intf: USB sideband client interface
+ * @notify_client: callback for xHCI sideband sequences
+ *
+ * FIXME usb device accessed via sideband Keeping track of sideband accessed usb devices.
+ */
+struct xhci_sideband {
+	struct xhci_hcd                 *xhci;
+	struct xhci_virt_device         *vdev;
+	struct xhci_virt_ep             *eps[EP_CTX_PER_DEV];
+	struct xhci_interrupter         *ir;
+	enum xhci_sideband_type		type;
+
+	/* Synchronizing xHCI sideband operations with client drivers operations */
+	struct mutex			mutex;
+
+	struct usb_interface		*intf;
+	int (*notify_client)(struct usb_interface *intf,
+			     struct xhci_sideband_event *evt);
+};
+
+struct xhci_sideband *
+xhci_sideband_register(struct usb_interface *intf, enum xhci_sideband_type type,
+		       int (*notify_client)(struct usb_interface *intf,
+				    struct xhci_sideband_event *evt));
+void
+xhci_sideband_unregister(struct xhci_sideband *sb);
+int
+xhci_sideband_add_endpoint(struct xhci_sideband *sb,
+			   struct usb_host_endpoint *host_ep);
+int
+xhci_sideband_remove_endpoint(struct xhci_sideband *sb,
+			      struct usb_host_endpoint *host_ep);
+int
+xhci_sideband_stop_endpoint(struct xhci_sideband *sb,
+			    struct usb_host_endpoint *host_ep);
+struct sg_table *
+xhci_sideband_get_endpoint_buffer(struct xhci_sideband *sb,
+				  struct usb_host_endpoint *host_ep);
+struct sg_table *
+xhci_sideband_get_event_buffer(struct xhci_sideband *sb);
+int
+xhci_sideband_create_interrupter(struct xhci_sideband *sb, int num_seg,
+				 bool ip_autoclear, u32 imod_interval, int intr_num);
+void
+xhci_sideband_remove_interrupter(struct xhci_sideband *sb);
+int
+xhci_sideband_interrupter_id(struct xhci_sideband *sb);
+
+#if IS_ENABLED(CONFIG_USB_XHCI_SIDEBAND)
+void xhci_sideband_notify_ep_ring_free(struct xhci_sideband *sb,
+				       unsigned int ep_index);
+#else
+static inline void xhci_sideband_notify_ep_ring_free(struct xhci_sideband *sb,
+						     unsigned int ep_index)
+{ }
+#endif /* IS_ENABLED(CONFIG_USB_XHCI_SIDEBAND) */
+#endif /* __LINUX_XHCI_SIDEBAND_H */