linux-kernel - [PATCH net v5 3/3] net: stmmac: fix unbalanced ptp clock issue in suspend/resume flow

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Date:   Thu, 14 Jul 2022 14:00:14 +0800
From:   Biao Huang <biao.huang@...iatek.com>
To:     David Miller <davem@...emloft.net>,
        Matthias Brugger <matthias.bgg@...il.com>
CC:     Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Jose Abreu <joabreu@...opsys.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Biao Huang <biao.huang@...iatek.com>, <netdev@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>, <macpaul.lin@...iatek.com>,
        Jisheng Zhang <jszhang@...nel.org>,
        Mohammad Athari Bin Ismail <mohammad.athari.ismail@...el.com>
Subject: [PATCH net v5 3/3] net: stmmac: fix unbalanced ptp clock issue in suspend/resume flow

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@...iatek.com>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c   | 17 ++++++++---------
 .../ethernet/stmicro/stmmac/stmmac_platform.c   |  8 +++++++-
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 197fac587ad5..c5f33630e771 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;
-- 
2.25.1