doc: net: Add information about gPTP

Add gPTP information to documentation.

Signed-off-by: Jukka Rissanen <[email protected]>
Signed-off-by: Julien Chevrier <[email protected]>

Author: jukkar

doc/subsystems/networking/gptp_release_notes.rst

@@ -0,0 +1,55 @@
+gPTP stack for Zephyr
+#####################
+
+Overview
+********
+
+This gPTP stack supports the protocol and procedures as defined in
+the IEEE 802.1AS-2011 standard (Timing and Syncronization for
+Time-Sensitive Applications in Bridged Local Area Networks).
+
+Supported features
+*******************
+
+The stack handles communications and state machines defined in the standard
+IEEE802.1AS-2011. Mandatory requirements, for a full-duplex point-to-point link
+endpoint, as defined in Annex A of the standard are supported.
+
+The stack is in principle capable of handling communications on multiple network
+interfaces (also defined as "ports" in the standard) and thus act as
+a 802.1AS bridge. However, this mode of operation has not been validated.
+
+Supported hardware
+******************
+
+Although the stack itself is hardware independent, ethernet frame timestamping
+support must be enabled in ethernet drivers.
+
+Boards supported:
+
+- NXP FRDM-K64F
+- QEMU (emulated, limited capabilities due to lack of hardware clock)
+
+Enabling the stack
+******************
+
+In menuconfig, the following configuration must me enabled:
+
+- CONFIG_NET_GPTP (Networking -> Link layer and IP networking support -> IP stack -> Link layer options -> Enable IEEE802.1AS support)
+
+Application interfaces
+**********************
+
+Only two Application Interfaces as defined in section 9 of the standard
+are available:
+
+- ClockTargetPhaseDiscontinuity interface (gptp_event_capture)
+- ClockTargetEventCapture interface (gptp_register_phase_dis_cb)
+
+Function prototypes can be found in "include/net/gptp.h".
+
+Testing
+*******
+
+The stack has been informally tested using the OpenAVB gPTP and
+Linux ptp4l daemons.