| Message ID | 20250206-dev-mctp-usb-v1-1-81453fe26a61@codeconstruct.com.au (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | mctp: Add MCTP-over-USB hardware transport binding | expand |
On Thu, Feb 06, 2025 at 02:48:23PM +0800, Jeremy Kerr wrote: > 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. Perhaps add a link to the spec? > + * > + * Copyright (C) 2024 Code Construct Pty Ltd It's 2025 now :) thanks, greg k-h
Hi Greg, Thanks for the review. > > --- /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. > > Perhaps add a link to the spec? Can do. I have one in the actual driver, but can replicate that here if it's helpful. > > + * > > + * Copyright (C) 2024 Code Construct Pty Ltd > > It's 2025 now :) WHAT?! :D (this was started in 2024, and I have some preliminary versions up since then, but I assume the last date is preferrable) Unless I hear otherwise, I'll v2 this after a netdev-appropriate backoff, with the added link and 2025 for both patches. Cheers, Jeremy
On Thu, Feb 06, 2025 at 03:11:25PM +0800, Jeremy Kerr wrote: > Hi Greg, > > Thanks for the review. > > > > --- /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. > > > > Perhaps add a link to the spec? > > Can do. I have one in the actual driver, but can replicate that here if > it's helpful. Isn't this a usb.org spec and not a vendor-specific one? > > > + * Copyright (C) 2024 Code Construct Pty Ltd > > > > It's 2025 now :) > > WHAT?! > > :D > > (this was started in 2024, and I have some preliminary versions up since > then, but I assume the last date is preferrable) As per copyright norms, list the real dates, so that would be: Copyright (C) 2024-2025 ... thanks, greg k-h
> Hi Greg, > > Can do. I have one in the actual driver, but can replicate that > > here if it's helpful. > > Isn't this a usb.org spec and not a vendor-specific one? Nope, all defined by the DMTF - so not really a vendor, but external to the USB-IF at least. The only mention of this under USB-IF is the class code allocation, along with the note: [0x14] This base class is defined for devices that conform to the “MCTP over USB” found at the DMTF website as DSP0283. This specification defines the usable set of SubClass and Protocol values. Values outside of this defined spec are reserved. These class codes can only be used in Interface Descriptors. > As per copyright norms, list the real dates, so that would be: > Copyright (C) 2024-2025 ... ack, will do. Cheers, Jeremy
On Thu, Feb 06, 2025 at 03:36:05PM +0800, Jeremy Kerr wrote: > > > Hi Greg, > > > > Can do. I have one in the actual driver, but can replicate that > > > here if it's helpful. > > > > Isn't this a usb.org spec and not a vendor-specific one? > > Nope, all defined by the DMTF - so not really a vendor, but external to > the USB-IF at least. The only mention of this under USB-IF is the class > code allocation, along with the note: > > [0x14] This base class is defined for devices that conform to the > “MCTP over USB” found at the DMTF website as DSP0283. This > specification defines the usable set of SubClass and Protocol > values. Values outside of this defined spec are reserved. These > class codes can only be used in Interface Descriptors. Ah, ok, then a link to the DSP0283 spec here in the .h file would be good. thanks, greg k-h
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. + * + * Copyright (C) 2024 Code Construct Pty Ltd + */ + +#ifndef __LINUX_USB_MCTP_USB_H +#define __LINUX_USB_MCTP_USB_H + +#include <linux/types.h> + +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 91f0f7e214a5a57c8bee3f44c4dbf7b175843d8c..052290652046591fba46f1f0cb5cf77fd965f555 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
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(+)