zhuhaijun753 / gptp

Introduction

This is an example Intel provided gptp daemon which can be used on Linux and Windows platforms. There are a number of other ptp daemons available for Linux which can be used to establish clock synchronization, although not all may export the required APIs needed for an AVB system.

The daemon communicates with other processes through a named pipe. The pipe name and message format is defined in ipcdef.hpp. The pipe name is "gptp-update". A Windows example is in the project named_pipe_test.

The message format is:

Integer64 <master-local phase offset>

Integer64 <local-system phase offset>

Float <master-local frequency offset>

Float <local-system frequency offset>

UInteger64 <local time of last update>

Meaning of IPC provided values

• master ~= local - <master-local phase offset>
• local ~= system - <local-system phase offset>
• Dmaster ~= Dlocal * (1-<master-local phase offset>/1e12) (where D denotes a delta rather than a specific value)
• Dlocal ~= Dsystem * (1-<local-system freq offset>/1e12) (where D denotes a delta rather than a specific value)

Linux Specific

Requirements for documentation on a ubuntu based system:

• cmake: sudo apt-get install cmake
• doxygen: sudo apt-get install doxygen
• graphviz: sudo apt-get install graphviz

To build, execute the linux/build makefile.

To build for I210:

ARCH=I210 make clean all

To build for 'generic' Linux:

make clean all

To build for Intel CE 5100 Platforms:

ARCH=IntelCE make clean all

To execute, run

./daemon_cl <interface-name>

such as

./daemon_cl eth0

The daemon creates a shared memory segment with the 'ptp' group. Some distributions may not have this group installed. The IPC interface will not available unless the 'ptp' group is available.

Windows Specific

Registry Changes

• Find the driver key: Go to device manager, device properties, details, and select driver key. For instance, the registry could be: {4d36e972-e325-11ce-bfc1-08002be10318}0000.
• Search the registry for the subkey found on the driver key above: Following the example above, search for 4d36e972-e325-11ce-bfc1-08002be10318 where there is a subkey 0000. For instance, it could be located at HKLM/System/ControlSet001/Control/Class.
• Add a DWORD value called TimeSync with a value of 1 to the subkey (0000 in the example above).
• Reset the driver by disabling and re-enabling (or reboot).

Build Dependencies

• WinPCAP Developer's Pack (WpdPack) is required for linking - downloadable from http://www.winpcap.org/devel.htm.
• CMAKE 3.2.2 or later
• Microsoft Visual Studio 2013 or later

The following environment variables must be defined: * WPCAP_DIR the directory where WinPcap is installed

• WinPCAP must also be installed on any machine where the daemon runs.

To run from the command line:

daemon_cl.exe xx-xx-xx-xx-xx-xx

where xx-xx-xx-xx-xx-xx is the mac address of the local interface

Windows Wireless Specific

Additional Driver/Hardware Requirements:

• Intel(R) 8260 Adapter
• Intel(R) PROSet/Wireless Software

The wireless software can be downloaded from:

https://downloadcenter.intel.com/ (Search)

Running the daemon:

Currently, the driver only works with peer-to-peer wireless connections. The connection must be established prior to running the daemon.

./gptp.exe -w <local hw device MAC> <local P2P MAC> <remove P2P MAC>

Other limitations:

Some versions of Windows(R) 10 do not allow WinPcap(R) to inject frames and the BMCA algorithm can't complete. The result is both peers assume the master role. To fix this, force one peer to be slave with the following command line:

./gptp.exe -w -R 255 <local hw device MAC> <local P2P MAC> <remove P2P MAC>

Other Available PTP Daemons

There are a number of existing ptp daemon projects. Some of the other known ptp daemons are listed below. Intel has not tested Open AVB with the following ptp daemons.

• Richard Cochran's ptp4l daemon - https://sourceforge.net/p/linuxptp/

  Note with this version to use gPTP specific settings, which differ slightly from IEEE 1588.

• http://ptpd.sourceforge.net/
• http://ptpd2.sourceforge.net/
• http://code.google.com/p/ptpv2d
• http://home.mit.bme.hu/~khazy/ptpd/