ice: Support cross-timestamping for E823 devices

The E822 hardware has cross timestamping support using a device feature
termed "Hammock Harbor" by the data sheet. This device feature is similar
to PCIe PTM, and captures the Always Running Timer (ART) simultaneously
with the PTP hardware clock time.

This functionality also exists on E823 devices, but is not currently
enabled.

Rename the cross-timestamp functions to use the _e82x postfix, indicating
that the support works across the E82x family of devices and not just the
E822 hardware.

The flow for capturing a cross-timestamp requires an additional step on
E823 devices. The GLTSYN_CMD register must be programmed with the READ_TIME
command. Otherwise, the cross timestamp will always report a value of zero
for the PTP hardware clock time.

To fix this, call ice_ptp_src_cmd() prior to initiating the cross timestamp
logic. Once the cross timestamp has completed, call ice_ptp_src_cmd() with
ICE_PTP_OP to ensure that the timer command registers are cleared.

Co-developed-by: Sergey Temerkhanov <sergey.temerkhanov@intel.com>
Signed-off-by: Sergey Temerkhanov <sergey.temerkhanov@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_ptp_hw.h b/drivers/net/ethernet/intel/ice/ice_ptp_hw.h
index 3079f1f903df..95f55a6627fb 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp_hw.h
+++ b/drivers/net/ethernet/intel/ice/ice_ptp_hw.h
@@ -203,6 +203,7 @@ extern const struct ice_vernier_info_e822 e822_vernier[NUM_ICE_PTP_LNK_SPD];
 u8 ice_get_ptp_src_clock_index(struct ice_hw *hw);
 bool ice_ptp_lock(struct ice_hw *hw);
 void ice_ptp_unlock(struct ice_hw *hw);
+void ice_ptp_src_cmd(struct ice_hw *hw, enum ice_ptp_tmr_cmd cmd);
 int ice_ptp_init_time(struct ice_hw *hw, u64 time);
 int ice_ptp_write_incval(struct ice_hw *hw, u64 incval);
 int ice_ptp_write_incval_locked(struct ice_hw *hw, u64 incval);