Allow user to control the latch point of ptp HW timestamps in E825
devices.

Usage, examples:

** Obtain current state:
$ cat /sys/class/net/eth<N>/device/ptp/ts_point
Command returns enum/integer:
* 1 - timestamp latched by PHY at the beginning of SFD,
* 2 - timestamp latched by PHY after the SFD,
* None - callback returns error to the user.

** Configure timestamp latch point at the beginning of SFD:
$ echo 1 > /sys/class/net/eth<N>/device/ptp/ts_point

** Configure timestamp latch point after the SFD:
$ echo 2 > /sys/class/net/eth<N>/device/ptp/ts_point

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
---
v3:
- improve readability, for "nothing to do" logic
- /s/PTP/ptp
- remove 'tx' from docs description
---
 drivers/net/ethernet/intel/ice/ice_ptp.c    | 44 +++++++++++++++
 drivers/net/ethernet/intel/ice/ice_ptp_hw.c | 60 +++++++++++++++++++++
 drivers/net/ethernet/intel/ice/ice_ptp_hw.h |  2 +
 3 files changed, 106 insertions(+)

diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
index a999fface272..c351c9707394 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp.c
+++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
@@ -2509,6 +2509,48 @@ static int ice_ptp_parse_sdp_entries(struct ice_pf *pf, __le16 *entries,
 	return 0;
 }
 
+/**
+ * ice_get_ts_point - get the timestamp latch point
+ * @info: the driver's ptp info structure
+ * @point: returns the configured timestamp latch point
+ *
+ * Return: 0 on success, negative on failure.
+ */
+static int ice_get_ts_point(struct ptp_clock_info *info,
+			    enum ptp_ts_point *point)
+{
+	struct ice_pf *pf = ptp_info_to_pf(info);
+	struct ice_hw *hw = &pf->hw;
+	int ret;
+
+	ice_ptp_lock(hw);
+	ret = ice_ptp_hw_ts_point_get(hw, point);
+	ice_ptp_unlock(hw);
+
+	return ret;
+}
+
+/**
+ * ice_set_ts_point - set the timestamp latch point
+ * @info: the driver's ptp info structure
+ * @point: requested timestamp latch point
+ *
+ * Return: 0 on success, negative on failure.
+ */
+static int ice_set_ts_point(struct ptp_clock_info *info,
+			    enum ptp_ts_point point)
+{
+	struct ice_pf *pf = ptp_info_to_pf(info);
+	struct ice_hw *hw = &pf->hw;
+	int ret;
+
+	ice_ptp_lock(hw);
+	ret = ice_ptp_hw_ts_point_set(hw, point);
+	ice_ptp_unlock(hw);
+
+	return ret;
+}
+
 /**
  * ice_ptp_set_funcs_e82x - Set specialized functions for E82X support
  * @pf: Board private structure
@@ -2529,6 +2571,8 @@ static void ice_ptp_set_funcs_e82x(struct ice_pf *pf)
 	if (ice_is_e825c(&pf->hw)) {
 		pf->ptp.ice_pin_desc = ice_pin_desc_e825c;
 		pf->ptp.info.n_pins = ICE_PIN_DESC_ARR_LEN(ice_pin_desc_e825c);
+		pf->ptp.info.set_ts_point = ice_set_ts_point;
+		pf->ptp.info.get_ts_point = ice_get_ts_point;
 	} else {
 		pf->ptp.ice_pin_desc = ice_pin_desc_e82x;
 		pf->ptp.info.n_pins = ICE_PIN_DESC_ARR_LEN(ice_pin_desc_e82x);
diff --git a/drivers/net/ethernet/intel/ice/ice_ptp_hw.c b/drivers/net/ethernet/intel/ice/ice_ptp_hw.c
index dfd49732bd5b..06c32f180932 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp_hw.c
+++ b/drivers/net/ethernet/intel/ice/ice_ptp_hw.c
@@ -6320,3 +6320,63 @@ int ice_cgu_get_output_pin_state_caps(struct ice_hw *hw, u8 pin_id,
 
 	return 0;
 }
+
+/**
+ * ice_ptp_hw_ts_point_get - check if timestamps are latched on/post SFD
+ * @hw: pointer to the HW struct
+ * @point: return the configured timestamp latch point
+ *
+ * Verify if HW timestamping point is configured to latch at the beginning or
+ * post of SFD (Start of Frame Delimiter)
+ *
+ * Return: 0 on success, negative on error
+ */
+int ice_ptp_hw_ts_point_get(struct ice_hw *hw, enum ptp_ts_point *point)
+{
+	u8 port = hw->port_info->lport;
+	u32 val;
+	int err;
+
+	err = ice_read_mac_reg_eth56g(hw, port, PHY_MAC_XIF_MODE, &val);
+	if (err)
+		return err;
+	if (val & PHY_MAC_XIF_TS_SFD_ENA_M)
+		*point = PTP_TS_POINT_SFD;
+	else
+		*point = PTP_TS_POINT_POST_SFD;
+
+	return err;
+}
+
+/**
+ * ice_ptp_hw_ts_point_set - configure timestamping on/post SFD
+ * @hw: pointer to the HW struct
+ * @point: requested timestamp latch point
+ *
+ * Configure timestamping to measure at the beginning/post SFD (Start of Frame
+ * Delimiter)
+ *
+ * Return: 0 on success, negative on error
+ */
+int ice_ptp_hw_ts_point_set(struct ice_hw *hw, enum ptp_ts_point point)
+{
+	u8 port = hw->port_info->lport;
+	int err, val;
+
+	err = ice_read_mac_reg_eth56g(hw, port, PHY_MAC_XIF_MODE, &val);
+	if (err)
+		return err;
+	if ((val & PHY_MAC_XIF_TS_SFD_ENA_M) && point == PTP_TS_POINT_SFD)
+		return -EINVAL;
+	if (!(val & PHY_MAC_XIF_TS_SFD_ENA_M) &&
+	    point == PTP_TS_POINT_POST_SFD)
+		return -EINVAL;
+	if (point == PTP_TS_POINT_SFD)
+		val |= PHY_MAC_XIF_TS_SFD_ENA_M;
+	else if (point == PTP_TS_POINT_POST_SFD)
+		val &= ~PHY_MAC_XIF_TS_SFD_ENA_M;
+	else
+		return -EINVAL;
+
+	return ice_write_mac_reg_eth56g(hw, port, PHY_MAC_XIF_MODE, val);
+}
diff --git a/drivers/net/ethernet/intel/ice/ice_ptp_hw.h b/drivers/net/ethernet/intel/ice/ice_ptp_hw.h
index 47af7c5c79b8..5e4edaee063e 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp_hw.h
+++ b/drivers/net/ethernet/intel/ice/ice_ptp_hw.h
@@ -348,6 +348,8 @@ void ice_ptp_init_hw(struct ice_hw *hw);
 int ice_get_phy_tx_tstamp_ready(struct ice_hw *hw, u8 block, u64 *tstamp_ready);
 int ice_ptp_one_port_cmd(struct ice_hw *hw, u8 configured_port,
 			 enum ice_ptp_tmr_cmd configured_cmd);
+int ice_ptp_hw_ts_point_get(struct ice_hw *hw, enum ptp_ts_point *point);
+int ice_ptp_hw_ts_point_set(struct ice_hw *hw, enum ptp_ts_point point);
 
 /* E822 family functions */
 int ice_read_quad_reg_e82x(struct ice_hw *hw, u8 quad, u16 offset, u32 *val);
-- 
2.38.1