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.

Fixes: f4da56529da6 ("net: stmmac: Add support for external trigger timestamping") 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: