Upcoming changes will add a USB host (and later gadget) driver for the
MCTP-over-USB protocol. Add a header that provides common definitions
for protocol support: the packet header format and a few framing
definitions. Add a define for the MCTP class code, as per
https://usb.org/defined-class-codes.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
---
 MAINTAINERS                  |  1 +
 include/linux/usb/mctp-usb.h | 28 ++++++++++++++++++++++++++++
 include/uapi/linux/usb/ch9.h |  1 +
 3 files changed, 30 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 79756f2100e001177191b129c48cf49e90173a68..f4e093674cf07260ca1cbb5a8873bdff782c614d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS

@@ -13775,6 +13775,7 @@ L:	netdev@vger.kernel.org
 S:	Maintained
 F:	Documentation/networking/mctp.rst
 F:	drivers/net/mctp/
+F:	include/linux/usb/mctp-usb.h
 F:	include/net/mctp.h
 F:	include/net/mctpdevice.h
 F:	include/net/netns/mctp.h

diff --git a/include/linux/usb/mctp-usb.h b/include/linux/usb/mctp-usb.h
new file mode 100644
index 0000000000000000000000000000000000000000..ad58a7edff8d5228717f9add22615c3fad7d4cde
--- /dev/null
+++ b/include/linux/usb/mctp-usb.h

@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * mctp-usb.h - MCTP USB transport binding: common definitions.
+ *
+ * These are protocol-level definitions, that may be shared between host
+ * and gadget drivers.