[PATCH net-next 0/4] net: stmmac: fix serdes power methods

[PATCH net-next 0/4] net: stmmac: fix serdes power methods

[Russell King (Oracle)]

The stmmac serdes powerup/powerdown methods are not guaranteed to be
called in a balancing fashion, but these are used to call the generic
PHY subsystem's phy_power_up() and phy_power_down() methods which do
require balanced calls.

This series addresses this by making the stmmac serdes methods balanced.

 drivers/net/ethernet/stmicro/stmmac/stmmac.h      |  1 +
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 65 ++++++++++++++---------
 2 files changed, 41 insertions(+), 25 deletions(-)

-- 
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[PATCH net-next 1/4] net: stmmac: add wrappers for serdes_power[up|down]() methods

[Russell King (Oracle)]

Add wrappers for the serdes_power[up|down]() methods and update all
call sites. This will allow us to add state tracking.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 48 +++++++++++--------
 1 file changed, 29 insertions(+), 19 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 9500b332a152..93d18709bc13 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -882,6 +882,26 @@ static void stmmac_release_ptp(struct stmmac_priv *priv)
 	clk_disable_unprepare(priv->plat->clk_ptp_ref);
 }
 
+static void stmmac_legacy_serdes_power_down(struct stmmac_priv *priv)
+{
+	if (priv->plat->serdes_powerdown)
+		priv->plat->serdes_powerdown(priv->dev, priv->plat->bsp_priv);
+}
+
+static int stmmac_legacy_serdes_power_up(struct stmmac_priv *priv)
+{
+	int ret;
+
+	if (!priv->plat->serdes_powerup)
+		return 0;
+
+	ret = priv->plat->serdes_powerup(priv->dev, priv->plat->bsp_priv);
+	if (ret < 0)
+		netdev_err(priv->dev, "SerDes powerup failed\n");
+
+	return ret;
+}
+
 /**
  *  stmmac_mac_flow_ctrl - Configure flow control in all queues
  *  @priv: driver private structure
@@ -981,9 +1001,8 @@ static void stmmac_mac_link_up(struct phylink_config *config,
 	u32 old_ctrl, ctrl;
 	int ret;
 
-	if ((priv->plat->flags & STMMAC_FLAG_SERDES_UP_AFTER_PHY_LINKUP) &&
-	    priv->plat->serdes_powerup)
-		priv->plat->serdes_powerup(priv->dev, priv->plat->bsp_priv);
+	if (priv->plat->flags & STMMAC_FLAG_SERDES_UP_AFTER_PHY_LINKUP)
+		stmmac_legacy_serdes_power_up(priv);
 
 	old_ctrl = readl(priv->ioaddr + MAC_CTRL_REG);
 	ctrl = old_ctrl & ~priv->hw->link.speed_mask;
@@ -4111,14 +4130,10 @@ static int __stmmac_open(struct net_device *dev,
 
 	stmmac_reset_queues_param(priv);
 
-	if (!(priv->plat->flags & STMMAC_FLAG_SERDES_UP_AFTER_PHY_LINKUP) &&
-	    priv->plat->serdes_powerup) {
-		ret = priv->plat->serdes_powerup(dev, priv->plat->bsp_priv);
-		if (ret < 0) {
-			netdev_err(priv->dev, "%s: Serdes powerup failed\n",
-				   __func__);
+	if (!(priv->plat->flags & STMMAC_FLAG_SERDES_UP_AFTER_PHY_LINKUP)) {
+		ret = stmmac_legacy_serdes_power_up(priv);
+		if (ret < 0)
 			goto init_error;
-		}
 	}
 
 	ret = stmmac_hw_setup(dev);
@@ -4222,8 +4237,7 @@ static void __stmmac_release(struct net_device *dev)
 	free_dma_desc_resources(priv, &priv->dma_conf);
 
 	/* Powerdown Serdes if there is */
-	if (priv->plat->serdes_powerdown)
-		priv->plat->serdes_powerdown(dev, priv->plat->bsp_priv);
+	stmmac_legacy_serdes_power_down(priv);
 
 	stmmac_release_ptp(priv);
 
@@ -8130,8 +8144,7 @@ int stmmac_suspend(struct device *dev)
 	/* Stop TX/RX DMA */
 	stmmac_stop_all_dma(priv);
 
-	if (priv->plat->serdes_powerdown)
-		priv->plat->serdes_powerdown(ndev, priv->plat->bsp_priv);
+	stmmac_legacy_serdes_power_down(priv);
 
 	/* Enable Power down mode by programming the PMT regs */
 	if (priv->wolopts) {
@@ -8233,11 +8246,8 @@ int stmmac_resume(struct device *dev)
 			stmmac_mdio_reset(priv->mii);
 	}
 
-	if (!(priv->plat->flags & STMMAC_FLAG_SERDES_UP_AFTER_PHY_LINKUP) &&
-	    priv->plat->serdes_powerup) {
-		ret = priv->plat->serdes_powerup(ndev,
-						 priv->plat->bsp_priv);
-
+	if (!(priv->plat->flags & STMMAC_FLAG_SERDES_UP_AFTER_PHY_LINKUP)) {
+		ret = stmmac_legacy_serdes_power_up(priv);
 		if (ret < 0)
 			return ret;
 	}
-- 
2.47.3

[PATCH net-next 2/4] net: stmmac: add state tracking for legacy serdes power state

[Russell King (Oracle)]

Avoid calling the serdes_powerdown() method if we have not had a
preceeding successful call to the serdes_powerup() method. This
avoids unbalancing refcounted resources that may be used in the
these platform glue serdes methods.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac.h      | 1 +
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 6 +++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 012b0a477255..5bd97aaaba86 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -303,6 +303,7 @@ struct stmmac_priv {
 	bool eee_enabled;
 	bool eee_active;
 	bool eee_sw_timer_en;
+	bool legacy_serdes_is_powered;
 	unsigned int mode;
 	unsigned int chain_mode;
 	int extend_desc;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 93d18709bc13..9efdde915229 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -884,8 +884,10 @@ static void stmmac_release_ptp(struct stmmac_priv *priv)
 
 static void stmmac_legacy_serdes_power_down(struct stmmac_priv *priv)
 {
-	if (priv->plat->serdes_powerdown)
+	if (priv->plat->serdes_powerdown && priv->legacy_serdes_is_powered)
 		priv->plat->serdes_powerdown(priv->dev, priv->plat->bsp_priv);
+
+	priv->legacy_serdes_is_powered = false;
 }
 
 static int stmmac_legacy_serdes_power_up(struct stmmac_priv *priv)
@@ -898,6 +900,8 @@ static int stmmac_legacy_serdes_power_up(struct stmmac_priv *priv)
 	ret = priv->plat->serdes_powerup(priv->dev, priv->plat->bsp_priv);
 	if (ret < 0)
 		netdev_err(priv->dev, "SerDes powerup failed\n");
+	else
+		priv->legacy_serdes_is_powered = true;
 
 	return ret;
 }
-- 
2.47.3

[PATCH net-next 3/4] net: stmmac: add missing serdes power down in error paths

[Russell King (Oracle)]

The open path is missing cleanup of a successful serdes power up if
stmmac_hw_setup() or stmmac_request_irq() fails.

stmmac_resume() is also missing cleanup of the serdes power up if
stmmac_hw_setup() fails.

Add the missing cleanups.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 9efdde915229..05b0b080bade 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4137,7 +4137,7 @@ static int __stmmac_open(struct net_device *dev,
 	if (!(priv->plat->flags & STMMAC_FLAG_SERDES_UP_AFTER_PHY_LINKUP)) {
 		ret = stmmac_legacy_serdes_power_up(priv);
 		if (ret < 0)
-			goto init_error;
+			return ret;
 	}
 
 	ret = stmmac_hw_setup(dev);
@@ -4170,6 +4170,7 @@ static int __stmmac_open(struct net_device *dev,
 
 	stmmac_release_ptp(priv);
 init_error:
+	stmmac_legacy_serdes_power_down(priv);
 	return ret;
 }
 
@@ -8273,6 +8274,7 @@ int stmmac_resume(struct device *dev)
 	ret = stmmac_hw_setup(ndev);
 	if (ret < 0) {
 		netdev_err(priv->dev, "%s: Hw setup failed\n", __func__);
+		stmmac_legacy_serdes_power_down(priv);
 		mutex_unlock(&priv->lock);
 		rtnl_unlock();
 		return ret;
-- 
2.47.3

[PATCH net-next 4/4] net: stmmac: move serdes power methods to stmmac_[open|release]()

[Russell King (Oracle)]

Move the SerDes power up and down calls for the non-"after linkup"
case out of __stmmac_open() and __stmmac_release() into the
stmmac_open() and stmmac_release() methods, which means the SerDes
will only change power state on administrative changes or suspend/
resume, not while changing the interface MTU.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 21 +++++++++----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 05b0b080bade..d561b0a0f5ac 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4134,12 +4134,6 @@ static int __stmmac_open(struct net_device *dev,
 
 	stmmac_reset_queues_param(priv);
 
-	if (!(priv->plat->flags & STMMAC_FLAG_SERDES_UP_AFTER_PHY_LINKUP)) {
-		ret = stmmac_legacy_serdes_power_up(priv);
-		if (ret < 0)
-			return ret;
-	}
-
 	ret = stmmac_hw_setup(dev);
 	if (ret < 0) {
 		netdev_err(priv->dev, "%s: Hw setup failed\n", __func__);
@@ -4170,7 +4164,6 @@ static int __stmmac_open(struct net_device *dev,
 
 	stmmac_release_ptp(priv);
 init_error:
-	stmmac_legacy_serdes_power_down(priv);
 	return ret;
 }
 
@@ -4196,9 +4189,15 @@ static int stmmac_open(struct net_device *dev)
 	if (ret)
 		goto err_runtime_pm;
 
+	if (!(priv->plat->flags & STMMAC_FLAG_SERDES_UP_AFTER_PHY_LINKUP)) {
+		ret = stmmac_legacy_serdes_power_up(priv);
+		if (ret < 0)
+			goto err_disconnect_phy;
+	}
+
 	ret = __stmmac_open(dev, dma_conf);
 	if (ret)
-		goto err_disconnect_phy;
+		goto err_serdes;
 
 	kfree(dma_conf);
 
@@ -4207,6 +4206,8 @@ static int stmmac_open(struct net_device *dev)
 
 	return ret;
 
+err_serdes:
+	stmmac_legacy_serdes_power_down(priv);
 err_disconnect_phy:
 	phylink_disconnect_phy(priv->phylink);
 err_runtime_pm:
@@ -4241,9 +4242,6 @@ static void __stmmac_release(struct net_device *dev)
 	/* Release and free the Rx/Tx resources */
 	free_dma_desc_resources(priv, &priv->dma_conf);
 
-	/* Powerdown Serdes if there is */
-	stmmac_legacy_serdes_power_down(priv);
-
 	stmmac_release_ptp(priv);
 
 	if (stmmac_fpe_supported(priv))
@@ -4269,6 +4267,7 @@ static int stmmac_release(struct net_device *dev)
 
 	__stmmac_release(dev);
 
+	stmmac_legacy_serdes_power_down(priv);
 	phylink_disconnect_phy(priv->phylink);
 	pm_runtime_put(priv->device);
 
-- 
2.47.3

Re: [PATCH net-next 0/4] net: stmmac: fix serdes power methods

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 3 Feb 2026 10:00:58 +0000 you wrote:
> The stmmac serdes powerup/powerdown methods are not guaranteed to be
> called in a balancing fashion, but these are used to call the generic
> PHY subsystem's phy_power_up() and phy_power_down() methods which do
> require balanced calls.
> 
> This series addresses this by making the stmmac serdes methods balanced.
> 
> [...]

Here is the summary with links:
  - [net-next,1/4] net: stmmac: add wrappers for serdes_power[up|down]() methods
    https://git.kernel.org/netdev/net-next/c/3302126a9b2b
  - [net-next,2/4] net: stmmac: add state tracking for legacy serdes power state
    https://git.kernel.org/netdev/net-next/c/9bfcf5460b70
  - [net-next,3/4] net: stmmac: add missing serdes power down in error paths
    https://git.kernel.org/netdev/net-next/c/3019a1333e66
  - [net-next,4/4] net: stmmac: move serdes power methods to stmmac_[open|release]()
    https://git.kernel.org/netdev/net-next/c/61aaa6253714

You are awesome, thank you!
-- 
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Re: [PATCH net-next 0/4] net: stmmac: fix serdes power methods

[Mohd Ayaan Anwar]

On Tue, Feb 03, 2026 at 10:00:58AM +0000, Russell King (Oracle) wrote:
> The stmmac serdes powerup/powerdown methods are not guaranteed to be
> called in a balancing fashion, but these are used to call the generic
> PHY subsystem's phy_power_up() and phy_power_down() methods which do
> require balanced calls.
> 
> This series addresses this by making the stmmac serdes methods balanced.
> 
>  drivers/net/ethernet/stmicro/stmmac/stmmac.h      |  1 +
>  drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 65 ++++++++++++++---------
>  2 files changed, 41 insertions(+), 25 deletions(-)
> 

For this series:

Tested-by: Mohd Ayaan Anwar <mohd.anwar@oss.qualcomm.com>

	Ayaan