This patchset adds the following: - A timecounter/cyclecounter based PHC for the free-running timestamping clock of this switch.
- A state machine implemented in the DSA tagger for SJA1105, which keeps track of metadata follow-up Ethernet frames (the switch's way of transmitting RX timestamps). - Some common-sense on whether or not frames should be timestamped was taken out of the mv88e6xxx driver (the only other DSA driver with PTP support) and moved to the generic framework. An option was also added for drivers to override these common-sense decisions, and timestamp some more frames. This was the path of least resistance after implementing the aforementioned state machine - metadata follow-up frames need to be tracked anyway even if only to discard them and not pass them up the network stack. And since the switch can't just be told to timestamp only what the kernel wants (PTP frames), simply use all the timestamps it provides. - A generic helper in the timecounter/cyclecounter code for reconstructing partial PTP timestamps, such as those generated by the SJA1105. Not all is rosy, though. PTP timestamping will only work when the ports are bridged. Otherwise, the metadata follow-up frames holding RX timestamps won't be received because they will be blocked by the master port's MAC filter. Linuxptp tries to put the net device in ALLMULTI/PROMISC mode, but DSA doesn't pass this on to the master port, which does the actual reception. The master port is put in promiscous mode when the slave ports are enslaved to a bridge. Also, even with software-corrected timestamps, one can observe a negative path delay reported by linuxptp: ptp4l[55.600]: master offset 8 s2 freq +83677 path delay -2390 ptp4l[56.600]: master offset 17 s2 freq +83688 path delay -2391 ptp4l[57.601]: master offset 6 s2 freq +83682 path delay -2391 ptp4l[58.601]: master offset -1 s2 freq +83677 path delay -2391 Without investigating too deeply, this appears to be introduced by the correction applied by linuxptp to t4 (t4c: corrected master rxtstamp) during the path delay estimation process (removing the correction makes the path delay positive). This does not appear to have an obvious negative effect upon the synchronization. Lastly, clock manipulations on the actual hardware PTP clock will have to be implemented anyway, for the TTEthernet block and the time-based ingress policer. Vladimir Oltean (5): timecounter: Add helper for reconstructing partial timestamps net: dsa: sja1105: Add support for the PTP clock net: dsa: mv88e6xxx: Let taggers specify a can_timestamp function net: dsa: sja1105: Add support for PTP timestamping net: dsa: sja1105: Increase priority of CPU-trapped frames drivers/net/dsa/mv88e6xxx/hwtstamp.c | 25 +- drivers/net/dsa/mv88e6xxx/hwtstamp.h | 4 +- drivers/net/dsa/sja1105/Kconfig | 7 + drivers/net/dsa/sja1105/Makefile | 1 + drivers/net/dsa/sja1105/sja1105.h | 30 ++ .../net/dsa/sja1105/sja1105_dynamic_config.c | 2 + drivers/net/dsa/sja1105/sja1105_main.c | 272 ++++++++++++- drivers/net/dsa/sja1105/sja1105_ptp.c | 357 ++++++++++++++++++ drivers/net/dsa/sja1105/sja1105_ptp.h | 48 +++ drivers/net/dsa/sja1105/sja1105_spi.c | 28 ++ .../net/dsa/sja1105/sja1105_static_config.c | 59 +++ .../net/dsa/sja1105/sja1105_static_config.h | 10 + include/linux/dsa/sja1105.h | 15 + include/linux/timecounter.h | 7 + include/net/dsa.h | 6 +- kernel/time/timecounter.c | 33 ++ net/dsa/dsa.c | 25 +- net/dsa/slave.c | 20 +- net/dsa/tag_sja1105.c | 135 ++++++- 19 files changed, 1043 insertions(+), 41 deletions(-) create mode 100644 drivers/net/dsa/sja1105/sja1105_ptp.c create mode 100644 drivers/net/dsa/sja1105/sja1105_ptp.h -- 2.17.1
