[PATCH RFC net-next 01/16] mctp: Add MCTP base

[Jeremy Kerr <jk@codeconstruct.com.au>]

Add basic Kconfig, an initial (empty) af_mctp source object, and
{AF,PF}_MCTP definitions.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
---
 MAINTAINERS               |  7 +++++++
 include/linux/socket.h    |  6 +++++-
 include/uapi/linux/mctp.h | 15 +++++++++++++++
 net/Kconfig               |  1 +
 net/Makefile              |  1 +
 net/mctp/Kconfig          | 13 +++++++++++++
 net/mctp/Makefile         |  3 +++
 net/mctp/af_mctp.c        |  7 +++++++
 8 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 include/uapi/linux/mctp.h
 create mode 100644 net/mctp/Kconfig
 create mode 100644 net/mctp/Makefile
 create mode 100644 net/mctp/af_mctp.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 503fd21901f1..5041ea78ab97 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10869,6 +10869,13 @@ F:	drivers/mailbox/arm_mhuv2.c
 F:	include/linux/mailbox/arm_mhuv2_message.h
 F:	Documentation/devicetree/bindings/mailbox/arm,mhuv2.yaml
 
+MANAGEMENT CONTROLLER TRANSPORT PROTOCOL (MCTP)
+M:	Jeremy Kerr <jk@codeconstruct.com.au>
+M:	Matt Johnston <matt@codeconstruct.com.au>
+L:	netdev@vger.kernel.org
+S:	Maintained
+F:	net/mctp/
+
 MAN-PAGES: MANUAL PAGES FOR LINUX -- Sections 2, 3, 4, 5, and 7
 M:	Michael Kerrisk <mtk.manpages@gmail.com>
 L:	linux-man@vger.kernel.org
diff --git a/include/linux/socket.h b/include/linux/socket.h
index b8fc5c53ba6f..40f866575d3d 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -223,8 +223,11 @@ struct ucred {
 				 * reuses AF_INET address family
 				 */
 #define AF_XDP		44	/* XDP sockets			*/
+#define AF_MCTP		45	/* Management controller
+				 * transport protocol
+				 */
 
-#define AF_MAX		45	/* For now.. */
+#define AF_MAX		46	/* For now.. */
 
 /* Protocol families, same as address families. */
 #define PF_UNSPEC	AF_UNSPEC
@@ -274,6 +277,7 @@ struct ucred {
 #define PF_QIPCRTR	AF_QIPCRTR
 #define PF_SMC		AF_SMC
 #define PF_XDP		AF_XDP
+#define PF_MCTP		AF_MCTP
 #define PF_MAX		AF_MAX
 
 /* Maximum queue length specifiable by listen.  */
diff --git a/include/uapi/linux/mctp.h b/include/uapi/linux/mctp.h
new file mode 100644
index 000000000000..eec6715143a0
--- /dev/null
+++ b/include/uapi/linux/mctp.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Management Controller Transport Protocol (MCTP)
+ *
+ * Copyright (c) 2021 Code Construct
+ * Copyright (c) 2021 Google
+ */
+
+#ifndef __UAPI_MCTP_H
+#define __UAPI_MCTP_H
+
+struct sockaddr_mctp {
+};
+
+#endif /* __UAPI_MCTP_H */
diff --git a/net/Kconfig b/net/Kconfig
index c7392c449b25..fb13460c6dab 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -363,6 +363,7 @@ source "net/bluetooth/Kconfig"
 source "net/rxrpc/Kconfig"
 source "net/kcm/Kconfig"
 source "net/strparser/Kconfig"
+source "net/mctp/Kconfig"
 
 config FIB_RULES
 	bool
diff --git a/net/Makefile b/net/Makefile
index 9ca9572188fe..fbfeb8a0bb37 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -78,3 +78,4 @@ obj-$(CONFIG_QRTR)		+= qrtr/
 obj-$(CONFIG_NET_NCSI)		+= ncsi/
 obj-$(CONFIG_XDP_SOCKETS)	+= xdp/
 obj-$(CONFIG_MPTCP)		+= mptcp/
+obj-$(CONFIG_MCTP)		+= mctp/
diff --git a/net/mctp/Kconfig b/net/mctp/Kconfig
new file mode 100644
index 000000000000..259aca76da60
--- /dev/null
+++ b/net/mctp/Kconfig
@@ -0,0 +1,13 @@
+
+menuconfig MCTP
+	depends on NET
+	tristate "MCTP core protocol support"
+	help
+	  Management Controller Transport Protocol (MCTP) is an in-system
+	  protocol for communicating between management controllers and
+	  their managed devices (peripherals, host processors, etc.). The
+	  protocol is defined by DMTF specification DSP0236.
+
+	  This option enables core MCTP support. For communicating with other
+	  devices, you'll want to enable a driver for a specific hardware
+	  channel.
diff --git a/net/mctp/Makefile b/net/mctp/Makefile
new file mode 100644
index 000000000000..7c056b1b7939
--- /dev/null
+++ b/net/mctp/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_MCTP) += mctp.o
+mctp-objs := af_mctp.o
diff --git a/net/mctp/af_mctp.c b/net/mctp/af_mctp.c
new file mode 100644
index 000000000000..87823fd3a11e
--- /dev/null
+++ b/net/mctp/af_mctp.c
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Management Controller Transport Protocol (MCTP)
+ *
+ * Copyright (c) 2021 Code Construct
+ * Copyright (c) 2021 Google
+ */
-- 
2.30.2