net: stmmac: propagate PTP addend and system time programming errors

stmmac_update_subsecond_increment() ignores the error returned by
stmmac_config_addend(), and stmmac_init_tstamp_counter() discards the
addend and system time programming errors, always returning success. A
failure to program the addend (PTP_TCR_TSADDREG) or to initialize the
system time counter (PTP_TCR_TSINIT) is therefore silently swallowed,
leaving the hardware timestamp counter in a non-running or partially
configured state while the driver keeps operating as if timestamping
were up. This matters for TAPRIO/EST offloading, which derives the gate
base time from the hardware timestamp counter.

The same hooks are also called from the PHC callbacks: settime64 and
adjfine drop the error and report success to clock_settime() and
clock_adjtime(), so a dead PTP reference clock goes unnoticed by
ptp4l/phc2sys.

Return error codes from stmmac_update_subsecond_increment(),
stmmac_init_tstamp_counter(), stmmac_dl_ts_coarse_set() and the
settime64/adjfine callbacks instead of silently returning success. On
failure, roll back the partially applied configuration so the hardware
and the driver bookkeeping stay consistent, and report the reason
through the devlink extack. Also guard against a zero sub-second
increment, which would otherwise divide by zero when computing the
addend.

Reset the persistent timestamping state (hwts_tx_en, hwts_rx_en,
tstamp_config, systime_flags and tsfupdt_coarse) when (re)initializing
timestamping, so a failed init does not leave TX/RX timestamping
enabled on a counter that never started.

Fixes: cc4c9001ce31 ("net: stmmac: Switch stmmac_hwtimestamp to generic HW Interface Helpers")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

0 files changed, 0 insertions, 0 deletions