From dcc35baae732b9079b2c6595cfd86da02b34a4e6 Mon Sep 17 00:00:00 2001 From: Jeremy Kerr Date: Fri, 21 Feb 2025 08:56:57 +0800 Subject: [PATCH] usb: Add base USB MCTP definitions 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 Acked-by: Greg Kroah-Hartman Link: https://patch.msgid.link/20250221-dev-mctp-usb-v3-1-3353030fe9cc@codeconstruct.com.au Signed-off-by: Jakub Kicinski --- MAINTAINERS | 1 + include/linux/usb/mctp-usb.h | 30 ++++++++++++++++++++++++++++++ include/uapi/linux/usb/ch9.h | 1 + 3 files changed, 32 insertions(+) create mode 100644 include/linux/usb/mctp-usb.h diff --git a/MAINTAINERS b/MAINTAINERS index b0cd54818bb31..8019d5a975468 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13896,6 +13896,7 @@ 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 0000000000000..a2f6f1e04efbd --- /dev/null +++ b/include/linux/usb/mctp-usb.h @@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * mctp-usb.h - MCTP USB transport binding: common definitions, + * based on DMTF0283 specification: + * https://www.dmtf.org/sites/default/files/standards/documents/DSP0283_1.0.1.pdf + * + * These are protocol-level definitions, that may be shared between host + * and gadget drivers. + * + * Copyright (C) 2024-2025 Code Construct Pty Ltd + */ + +#ifndef __LINUX_USB_MCTP_USB_H +#define __LINUX_USB_MCTP_USB_H + +#include + +struct mctp_usb_hdr { + __be16 id; + u8 rsvd; + u8 len; +} __packed; + +#define MCTP_USB_XFER_SIZE 512 +#define MCTP_USB_BTU 68 +#define MCTP_USB_MTU_MIN MCTP_USB_BTU +#define MCTP_USB_MTU_MAX (U8_MAX - sizeof(struct mctp_usb_hdr)) +#define MCTP_USB_DMTF_ID 0x1ab4 + +#endif /* __LINUX_USB_MCTP_USB_H */ diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h index 91f0f7e214a5a..0522906520465 100644 --- a/include/uapi/linux/usb/ch9.h +++ b/include/uapi/linux/usb/ch9.h @@ -330,6 +330,7 @@ struct usb_device_descriptor { #define USB_CLASS_AUDIO_VIDEO 0x10 #define USB_CLASS_BILLBOARD 0x11 #define USB_CLASS_USB_TYPE_C_BRIDGE 0x12 +#define USB_CLASS_MCTP 0x14 #define USB_CLASS_MISC 0xef #define USB_CLASS_APP_SPEC 0xfe #define USB_SUBCLASS_DFU 0x01