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From:   Noor Azura Ahmad Tarmizi <noor.azura.ahmad.tarmizi@intel.com>
To:     "David S . Miller" <davem@davemloft.net>,
        Giuseppe Cavallaro <peppe.cavallaro@st.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Jose Abreu <joabreu@synopsys.com>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Richard Cochran <richardcochran@gmail.com>
Cc:     netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Noor Azura Ahmad Tarmizi 
        <noor.azura.ahmad.tarmizi@linux.intel.com>,
        Tan Tee Min <tee.min.tan@intel.com>,
        Looi Hong Aun <hong.aun.looi@intel.com>,
        Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>,
        Noor Azura Ahmad Tarmizi <noor.azura.ahmad.tarmizi@intel.com>,
        stable@vger.kernel.org
Subject: [PATCH net 1/1] net: stmmac: add aux timestamps fifo clearance wait
Date:   Mon,  9 Jan 2023 23:15:46 +0800
Message-Id: <20230109151546.26247-1-noor.azura.ahmad.tarmizi@intel.com>
Precedence: bulk

Add timeout polling wait for auxiliary timestamps snapshot FIFO clear bit
(ATSFC) to clear. This is to ensure no residue fifo value is being read
erroneously.

Cc: <stable@vger.kernel.org> # 5.10.x
Signed-off-by: Noor Azura Ahmad Tarmizi <noor.azura.ahmad.tarmizi@intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
index fc06ddeac0d5..b4388ca8d211 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c
@@ -210,7 +210,10 @@ static int stmmac_enable(struct ptp_clock_info *ptp,
 		}
 		writel(acr_value, ptpaddr + PTP_ACR);
 		mutex_unlock(&priv->aux_ts_lock);
-		ret = 0;
+		/* wait for auxts fifo clear to finish */
+		ret = readl_poll_timeout(ptpaddr + PTP_ACR, acr_value,
+					 !(acr_value & PTP_ACR_ATSFC),
+					 10, 10000);
 		break;
 
 	default:
-- 
2.17.1