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>

drivers/net/ethernet/intel/ice/ice_ptp.c

@@ -1993,6 +1993,9 @@ ice_ptp_get_syncdevicetime(ktime_t *device,
 		return -EBUSY;
 	}
 
+	/* Program cmd to master timer */
+	ice_ptp_src_cmd(hw, ICE_PTP_READ_TIME);
+
 	/* Start the ART and device clock sync sequence */
 	hh_art_ctl = rd32(hw, GLHH_ART_CTL);
 	hh_art_ctl = hh_art_ctl | GLHH_ART_CTL_ACTIVE_M;
@@ -2022,6 +2025,10 @@ ice_ptp_get_syncdevicetime(ktime_t *device,
 			break;
 		}
 	}
+
+	/* Clear the master timer */
+	ice_ptp_src_cmd(hw, ICE_PTP_NOP);
+
 	/* Release HW lock */
 	hh_lock = rd32(hw, PFHH_SEM + (PFTSYN_SEM_BYTES * hw->pf_id));
 	hh_lock = hh_lock & ~PFHH_SEM_BUSY_M;
@@ -2034,22 +2041,22 @@ ice_ptp_get_syncdevicetime(ktime_t *device,
 }
 
 /**
- * ice_ptp_getcrosststamp_e822 - Capture a device cross timestamp
+ * ice_ptp_getcrosststamp_e82x - Capture a device cross timestamp
  * @info: the driver's PTP info structure
  * @cts: The memory to fill the cross timestamp info
  *
  * Capture a cross timestamp between the ART and the device PTP hardware
  * clock. Fill the cross timestamp information and report it back to the
  * caller.
  *
- * This is only valid for E822 devices which have support for generating the
- * cross timestamp via PCIe PTM.
+ * This is only valid for E822 and E823 devices which have support for
+ * generating the cross timestamp via PCIe PTM.
  *
  * In order to correctly correlate the ART timestamp back to the TSC time, the
  * CPU must have X86_FEATURE_TSC_KNOWN_FREQ.
  */
 static int
-ice_ptp_getcrosststamp_e822(struct ptp_clock_info *info,
+ice_ptp_getcrosststamp_e82x(struct ptp_clock_info *info,
 			    struct system_device_crosststamp *cts)
 {
 	struct ice_pf *pf = ptp_info_to_pf(info);
@@ -2283,22 +2290,22 @@ ice_ptp_setup_pins_e823(struct ice_pf *pf, struct ptp_clock_info *info)
 }
 
 /**
- * ice_ptp_set_funcs_e822 - Set specialized functions for E822 support
+ * ice_ptp_set_funcs_e82x - Set specialized functions for E82x support
  * @pf: Board private structure
  * @info: PTP info to fill
  *
- * Assign functions to the PTP capabiltiies structure for E822 devices.
+ * Assign functions to the PTP capabiltiies structure for E82x devices.
  * Functions which operate across all device families should be set directly
- * in ice_ptp_set_caps. Only add functions here which are distinct for E822
+ * in ice_ptp_set_caps. Only add functions here which are distinct for E82x
  * devices.
  */
 static void
-ice_ptp_set_funcs_e822(struct ice_pf *pf, struct ptp_clock_info *info)
+ice_ptp_set_funcs_e82x(struct ice_pf *pf, struct ptp_clock_info *info)
 {
 #ifdef CONFIG_ICE_HWTS
 	if (boot_cpu_has(X86_FEATURE_ART) &&
 	    boot_cpu_has(X86_FEATURE_TSC_KNOWN_FREQ))
-		info->getcrosststamp = ice_ptp_getcrosststamp_e822;
+		info->getcrosststamp = ice_ptp_getcrosststamp_e82x;
 #endif /* CONFIG_ICE_HWTS */
 }
 
@@ -2332,6 +2339,8 @@ ice_ptp_set_funcs_e810(struct ice_pf *pf, struct ptp_clock_info *info)
 static void
 ice_ptp_set_funcs_e823(struct ice_pf *pf, struct ptp_clock_info *info)
 {
+	ice_ptp_set_funcs_e82x(pf, info);
+
 	info->enable = ice_ptp_gpio_enable_e823;
 	ice_ptp_setup_pins_e823(pf, info);
 }
@@ -2359,7 +2368,7 @@ static void ice_ptp_set_caps(struct ice_pf *pf)
 	else if (ice_is_e823(&pf->hw))
 		ice_ptp_set_funcs_e823(pf, info);
 	else
-		ice_ptp_set_funcs_e822(pf, info);
+		ice_ptp_set_funcs_e82x(pf, info);
 }
 
 /**

drivers/net/ethernet/intel/ice/ice_ptp_hw.c

@@ -233,7 +233,7 @@ static u64 ice_ptp_read_src_incval(struct ice_hw *hw)
  *
  * Prepare the source timer for an upcoming timer sync command.
  */
-static void ice_ptp_src_cmd(struct ice_hw *hw, enum ice_ptp_tmr_cmd cmd)
+void ice_ptp_src_cmd(struct ice_hw *hw, enum ice_ptp_tmr_cmd cmd)
 {
 	u32 cmd_val;
 	u8 tmr_idx;

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);