rust: usb: add basic USB abstractions

Add basic USB abstractions, consisting of usb::{Device, Interface,
Driver, Adapter, DeviceId} and the module_usb_driver macro. This is the
first step in being able to write USB device drivers, which paves the
way for USB media drivers - for example - among others.

This initial support will then be used by a subsequent sample driver,
which constitutes the only user of the USB abstractions so far.

Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>
Link: https://lore.kernel.org/r/20250825-b4-usb-v1-1-7aa024de7ae8@collabora.com
[ force USB = y for now - gregkh ]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: danielalmeida-collabora

rust/bindings/bindings_helper.h

@@ -74,6 +74,7 @@
 #include <linux/slab.h>
 #include <linux/task_work.h>
 #include <linux/tracepoint.h>
+#include <linux/usb.h>
 #include <linux/wait.h>
 #include <linux/workqueue.h>
 #include <linux/xarray.h>

rust/helpers/helpers.c

@@ -48,6 +48,7 @@
 #include "task.c"
 #include "time.c"
 #include "uaccess.c"
+#include "usb.c"
 #include "vmalloc.c"
 #include "wait.c"
 #include "workqueue.c"

rust/helpers/usb.c

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/usb.h>
+
+struct usb_device *rust_helper_interface_to_usbdev(struct usb_interface *intf)
+{
+	return interface_to_usbdev(intf);
+}

rust/kernel/lib.rs

@@ -127,6 +127,8 @@ pub mod time;
 pub mod tracepoint;
 pub mod transmute;
 pub mod types;
+#[cfg(CONFIG_USB = "y")]
+pub mod usb;
 pub mod uaccess;
 pub mod workqueue;
 pub mod xarray;