kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-11-10 20:48:12 +00:00
Code Issues Releases Packages Activity

ice: monitor TSPLL lock from PTP periodic worker

Browse source 
On E825 devices that own the source timer, the TSPLL can lose lock when
the TCXO or TIME_REF signal is disrupted. Recovery requires re-enabling
the TSPLL via CGU register writes; without it, the PHC keeps running on
a degraded reference indefinitely.

The DPLL periodic worker (ice_dpll_periodic_work()) would be a natural
home for this monitoring, but placing it there has two problems:

  1. ice_dpll_init_e825() sets ICE_FLAG_DPLL only after all initialization
     steps succeed. If any earlier step fails, the driver would run
     without any TSPLL recovery mechanism.

  2. When CONFIG_DPLL=n, the DPLL worker is compiled out and TSPLL
     recovery would be silently absent.

Add the monitor to ice_ptp_periodic_work() instead, which always runs on
E825 owner PFs regardless of DPLL init state or config. Introduce two
small helpers, ice_tspll_lost_lock_e825c() and ice_tspll_restart_e825c(),
which encapsulate the CGU register reads/writes required to observe and
recover the TSPLL.

Cache the observed lock state in pf->ptp.tspll_locked using
WRITE_ONCE()/READ_ONCE() so a follow-up change can consume it from the
DPLL periodic worker (for user-space notification via
dpll_device_change_ntf()) and drop the redundant poll+recovery from
that path. Precise synchronization is not required: both workers converge
on the same value within one poll period.

Reviewed-by: Przemyslaw Korba <przemyslaw.korba@intel.com>
Signed-off-by: Grzegorz Nitka <grzegorz.nitka@intel.com>
Tested-by: Alexander Nowlin <alexander.nowlin@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
This commit is contained in:
Grzegorz Nitka 2026-08-03 13:35:05 +02:00 • committed by Tony Nguyen
commit e72d09173c
4 changed files with 170 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files