[PATCH net 04/10] ice: ptp: serialize E825 PHY timer start with PTP lock

[Tony Nguyen <anthony.l.nguyen@intel.com>]

From: Grzegorz Nitka <grzegorz.nitka@intel.com>

ice_start_phy_timer_eth56g() programs TIMETUS registers and issues
INIT_INCVAL without holding the global PTP semaphore.

This allows concurrent PTP command paths to interleave with PHY timer
start, which can make the sequence fail and leave timer initialization
inconsistent.

Take the PTP lock around TIMETUS registers programming and INIT_INCVAL
command execution, and make sure the lock is released on all error paths.

Keep the subsequent sync step outside of this critical section, since
ice_sync_phy_timer_eth56g() takes the same semaphore internally.

Fixes: 7cab44f1c35f ("ice: Introduce ETH56G PHY model for E825C products")
Reviewed-by: Arkadiusz Kubalewski <Arkadiusz.kubalewski@intel.com>
Signed-off-by: Grzegorz Nitka <grzegorz.nitka@intel.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Tested-by: Alexander Nowlin <alexander.nowlin@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
---
 drivers/net/ethernet/intel/ice/ice_ptp_hw.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_ptp_hw.c b/drivers/net/ethernet/intel/ice/ice_ptp_hw.c
index 672218e5d1f9..8bb94e785f2a 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp_hw.c
+++ b/drivers/net/ethernet/intel/ice/ice_ptp_hw.c
@@ -2141,16 +2141,23 @@ int ice_start_phy_timer_eth56g(struct ice_hw *hw, u8 port)
 	}
 	incval = (u64)hi << 32 | lo;
 
+	if (!ice_ptp_lock(hw)) {
+		dev_err(ice_hw_to_dev(hw), "Failed to acquire PTP semaphore\n");
+		return -EBUSY;
+	}
+
 	err = ice_write_40b_ptp_reg_eth56g(hw, port, PHY_REG_TIMETUS_L, incval);
 	if (err)
-		return err;
+		goto err_ptp_unlock;
 
 	err = ice_ptp_one_port_cmd(hw, port, ICE_PTP_INIT_INCVAL);
 	if (err)
-		return err;
+		goto err_ptp_unlock;
 
 	ice_ptp_exec_tmr_cmd(hw);
 
+	ice_ptp_unlock(hw);
+
 	err = ice_sync_phy_timer_eth56g(hw, port);
 	if (err)
 		return err;
@@ -2166,6 +2173,10 @@ int ice_start_phy_timer_eth56g(struct ice_hw *hw, u8 port)
 	ice_debug(hw, ICE_DBG_PTP, "Enabled clock on PHY port %u\n", port);
 
 	return 0;
+
+err_ptp_unlock:
+	ice_ptp_unlock(hw);
+	return err;
 }
 
 /**
-- 
2.47.1