As discussed in this email thread:
https://sourceforge.net/p/linuxptp/mailman/message/37047555/
there is a desire to synchronize multiple DSA switches in a
boundary_clock_jbod setup, using a PPS signal, and the ts2phc program
already offers a solid base.
This patch series extends the ts2phc program to cater for that use case
by introducing a new '-a' option and friends ('--transportSpecific').
This makes it quite similar to phc2sys which has the same ability, just
that ts2phc can give much better performance if the hardware can assist
with that.
The overall board design for my use case is that there's an SoC with an
embedded DSA switch, and hanging off of 3 ports of that embedded switch
are 3 external switches. Every networking device (the DSA master for the
embedded switch, the embedded switch, as well as each individual
external switch) has a PTP clock. The topology for PPS signal
distribution is fixed - that is given by hardware ability - the
/dev/ptp1 clock can emit a valid PPS, and all external switches can
timestamp that PPS (it is connected in a sort-of simplex "bus" design),
and it cannot be any other way around. It looks like this:
+---------------------------------------------------------------+
| LS1028A /dev/ptp0 (unused) |
| +------------------------------+ |
| | DSA master for Felix | |
| |(internal ENETC port 2: eno2))| |
| +------------+------------------------------+-------------+ |
| | Felix embedded L2 switch /dev/ptp1 | |
| | PPS master, sync slave | |
| | +--------------+ +--------------+ +--------------+ | |
| | |DSA master for| |DSA master for| |DSA master for| | |
| | | SJA1105 1 | | SJA1105 2 | | SJA1105 3 | | |
| | |(Felix port 1)| |(Felix port 2)| |(Felix port 3)| | |
+--+-+--------------+---+--------------+---+--------------+--+--+
/dev/ptp2 /dev/ptp3 /dev/ptp4
PPS slave, sync master PPS slave, sync slave PPS slave, sync slave
+-----------------------+ +-----------------------+ +-----------------------+
| SJA1105 switch 1 | | SJA1105 switch 2 | | SJA1105 switch 3 |
+-----+-----+-----+-----+ +-----+-----+-----+-----+ +-----+-----+-----+-----+
|sw1p0|sw1p1|sw1p2|sw1p3| |sw2p0|sw2p1|sw2p2|sw2p3| |sw3p0|sw3p1|sw3p2|sw3p3|
+-----+-----+-----+-----+ +-----+-----+-----+-----+ +-----+-----+-----+-----+
^
|
GM connected here
In text, it would be described as this:
cat ts2phc.cfg
[global]
first_step_threshold 0.00002
step_threshold 0.00002
ts2phc.pulsewidth 500000000
ts2phc.perout_phase 0
# Felix
[/dev/ptp1]
ts2phc.master 1
# SJA1105 switch 1
[/dev/ptp2]
ts2phc.channel 0
ts2phc.extts_polarity both
# SJA1105 switch 2
[/dev/ptp3]
ts2phc.channel 0
ts2phc.extts_polarity both
# SJA1105 switch 3
[/dev/ptp4]
ts2phc.channel 0
ts2phc.extts_polarity both
cat gPTP.cfg
[global]
gmCapable 1
priority1 248
priority2 248
logAnnounceInterval 0
logSyncInterval -3
syncReceiptTimeout 3
neighborPropDelayThresh 50000
min_neighbor_prop_delay -20000000
assume_two_step 1
path_trace_enabled 1
follow_up_info 1
transportSpecific 0x1
ptp_dst_mac 01:80:C2:00:00:0E
network_transport L2
delay_mechanism P2P
step_threshold 0.00002
tx_timestamp_timeout 20
boundary_clock_jbod 1
[sw1p0]
[sw1p1]
[sw1p2]
[sw1p3]
[sw2p0]
[sw2p1]
[sw2p2]
[sw2p3]
[sw3p0]
[sw3p1]
[sw3p2]
[sw3p3]
At a high level, what I have done is:
- I moved the PMC related code from phc2sys into pmc_common.c, for
ts2phc reuse
- I created an extra abstraction in ts2phc as "struct clock" that would
represent what's synchronizable. The "master" and "slave" concepts
retain their meaning, which is: "master" == the device that emits PPS,
and "slave" == the device that timestamps PPS.
The changes should be backwards-compatible with the non-automatic mode.
I have only tested non-automatic mode with a PHC master (that's all I
have) and it still appears to work as before.
Vladimir Oltean (15):
posix_clock_open: derive PHC index from device name if possible
phc2sys: rename struct node to struct phc2sys_private
phc2sys: break out pmc code into pmc_common.c
pmc_common: fix potential memory leak in run_pmc_events()
ts2phc: create a private data structure
ts2phc: instantiate a full clock structure for every slave PHC
ts2phc: instantiate a full clock structure for every PHC master
ts2phc: instantiate a pmc node
ts2phc_slave: print master offset
ts2phc: split slave poll from servo loop
tmv: introduce a conversion helper from ptp_clock_time
tmv: introduce an initializer from nanoseconds
ts2phc: reconfigure sync direction by subscribing to ptp4l port events
ts2phc: allow the PHC PPS master to be synchronized
ts2phc_phc_master: make use of new kernel API for perout waveform
config.c | 1 +
makefile | 3 +-
missing.h | 53 ++++
phc2sys.c | 667 +++++++++++-----------------------------
pmc_common.c | 342 ++++++++++++++++++++
pmc_common.h | 35 +++
tmv.h | 15 +
ts2phc.8 | 5 +
ts2phc.c | 621 ++++++++++++++++++++++++++++++++++---
ts2phc.h | 77 +++++
ts2phc_generic_master.c | 2 +-
ts2phc_generic_master.h | 3 +-
ts2phc_master.c | 10 +-
ts2phc_master.h | 8 +-
ts2phc_master_private.h | 1 +
ts2phc_nmea_master.c | 5 +-
ts2phc_nmea_master.h | 3 +-
ts2phc_phc_master.c | 70 +++--
ts2phc_phc_master.h | 3 +-
ts2phc_slave.c | 383 ++++++++++++-----------
ts2phc_slave.h | 10 +-
util.c | 10 +
22 files changed, 1577 insertions(+), 750 deletions(-)
create mode 100644 ts2phc.h
--
2.25.1
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