Patch "net: stmmac: fix unbalanced ptp clock issue in suspend/resume flow" has been added to the 5.18-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    net: stmmac: fix unbalanced ptp clock issue in suspend/resume flow

to the 5.18-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-stmmac-fix-unbalanced-ptp-clock-issue-in-suspend.patch
and it can be found in the queue-5.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 1c157dbb3a0ba203cf08104dbeb84dfb9d4b56cd
Author: Biao Huang <biao.huang@xxxxxxxxxxxx>
Date:   Thu Jul 14 14:00:14 2022 +0800

    net: stmmac: fix unbalanced ptp clock issue in suspend/resume flow
    
    [ Upstream commit f4c7d8948e866918d61493264dbbd67e45ef2bda ]
    
    Current stmmac driver will prepare/enable ptp_ref clock in
    stmmac_init_tstamp_counter().
    
    The stmmac_pltfr_noirq_suspend will disable it once in suspend flow.
    
    But in resume flow,
            stmmac_pltfr_noirq_resume --> stmmac_init_tstamp_counter
            stmmac_resume --> stmmac_hw_setup --> stmmac_init_ptp --> stmmac_init_tstamp_counter
    ptp_ref clock reference counter increases twice, which leads to unbalance
    ptp clock when resume back.
    
    Move ptp_ref clock prepare/enable out of stmmac_init_tstamp_counter to fix it.
    
    Fixes: 0735e639f129d ("net: stmmac: skip only stmmac_ptp_register when resume from suspend")
    Signed-off-by: Biao Huang <biao.huang@xxxxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index d43c9ba0b270..6a7f63a58aef 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -834,19 +834,10 @@ int stmmac_init_tstamp_counter(struct stmmac_priv *priv, u32 systime_flags)
 	struct timespec64 now;
 	u32 sec_inc = 0;
 	u64 temp = 0;
-	int ret;
 
 	if (!(priv->dma_cap.time_stamp || priv->dma_cap.atime_stamp))
 		return -EOPNOTSUPP;
 
-	ret = clk_prepare_enable(priv->plat->clk_ptp_ref);
-	if (ret < 0) {
-		netdev_warn(priv->dev,
-			    "failed to enable PTP reference clock: %pe\n",
-			    ERR_PTR(ret));
-		return ret;
-	}
-
 	stmmac_config_hw_tstamping(priv, priv->ptpaddr, systime_flags);
 	priv->systime_flags = systime_flags;
 
@@ -3270,6 +3261,14 @@ static int stmmac_hw_setup(struct net_device *dev, bool ptp_register)
 
 	stmmac_mmc_setup(priv);
 
+	if (ptp_register) {
+		ret = clk_prepare_enable(priv->plat->clk_ptp_ref);
+		if (ret < 0)
+			netdev_warn(priv->dev,
+				    "failed to enable PTP reference clock: %pe\n",
+				    ERR_PTR(ret));
+	}
+
 	ret = stmmac_init_ptp(priv);
 	if (ret == -EOPNOTSUPP)
 		netdev_info(priv->dev, "PTP not supported by HW\n");
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 11e1055e8260..9f5cac4000da 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -815,7 +815,13 @@ static int __maybe_unused stmmac_pltfr_noirq_resume(struct device *dev)
 		if (ret)
 			return ret;
 
-		stmmac_init_tstamp_counter(priv, priv->systime_flags);
+		ret = clk_prepare_enable(priv->plat->clk_ptp_ref);
+		if (ret < 0) {
+			netdev_warn(priv->dev,
+				    "failed to enable PTP reference clock: %pe\n",
+				    ERR_PTR(ret));
+			return ret;
+		}
 	}
 
 	return 0;