[PATCH net-next v2 0/7] net: stmmac: deprecate "snps,en-tx-lpi-clockgating" property

[PATCH net-next v2 0/7] net: stmmac: deprecate "snps,en-tx-lpi-clockgating" property

[Russell King (Oracle)]

On Sun, Mar 09, 2025 at 03:01:45PM +0000, Russell King (Oracle) wrote:
Hi,

This series deprecates the "snps,en-tx-lpi-clockgating" property for
stmmac.

MII Transmit clock gating, where the MAC hardware supports gating this
clock, is a function of the connected PHY capabilities, which it
reports through its status register.

GMAC versions that support transmit clock gating twiddle the LPITCSE
bit accordingly in the LPI control/status register, which is handled
by the GMAC core specific code.

So, "snps,en-tx-lpi-clockgating" not something that is a GMAC property,
but is a work-around for phylib not providing an interface to determine
whether the PHY allows the transmit clock to be disabled.

This series converts the two SoCs that make use of this property (which,
I hasten to add, is set in the SoC code) to use the PHY capability bit
instead of a DT property, then removes the DT property from the .dtsi,
deprecates it in the snps,dwmac binding, and finally in the stmmac code.

I am expecting some discussion on how to merge this, as I think the
order in which these changes is made is important - we don't want to
deprecate the old way until the new code has landed.

Changes in v2:
- Correct Cc list

 Documentation/devicetree/bindings/net/snps,dwmac.yaml |  1 +
 arch/arm/boot/dts/st/stm32mp151.dtsi                  |  1 -
 arch/riscv/boot/dts/starfive/jh7110.dtsi              |  2 --
 drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c  |  1 +
 drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c     |  1 +
 drivers/net/ethernet/stmicro/stmmac/stmmac.h          |  1 +
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c     | 16 ++++++++++++----
 drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c |  5 ++++-
 include/linux/stmmac.h                                |  3 ++-
 9 files changed, 22 insertions(+), 9 deletions(-)

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

[PATCH net-next v2 1/7] net: stmmac: allow platforms to use PHY tx clock stop capability

[Russell King (Oracle)]

Allow platform glue to instruct stmmac to make use of the PHY transmit
clock stop capability when deciding whether to allow the transmit clock
from the DWMAC core to be stopped.

Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac.h     |  1 +
 .../net/ethernet/stmicro/stmmac/stmmac_main.c    | 16 ++++++++++++----
 include/linux/stmmac.h                           |  3 ++-
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index d87275c1cf23..bddfa0f4aa21 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -306,6 +306,7 @@ struct stmmac_priv {
 	struct timer_list eee_ctrl_timer;
 	int lpi_irq;
 	u32 tx_lpi_timer;
+	bool tx_lpi_clk_stop;
 	bool eee_enabled;
 	bool eee_active;
 	bool eee_sw_timer_en;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index fa1d7d3a2f43..6f29804148b6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -457,8 +457,7 @@ static void stmmac_try_to_start_sw_lpi(struct stmmac_priv *priv)
 	/* Check and enter in LPI mode */
 	if (!priv->tx_path_in_lpi_mode)
 		stmmac_set_lpi_mode(priv, priv->hw, STMMAC_LPI_FORCED,
-			priv->plat->flags & STMMAC_FLAG_EN_TX_LPI_CLOCKGATING,
-			0);
+				    priv->tx_lpi_clk_stop, 0);
 }
 
 /**
@@ -1104,13 +1103,18 @@ static int stmmac_mac_enable_tx_lpi(struct phylink_config *config, u32 timer,
 
 	priv->eee_enabled = true;
 
+	/* Update the transmit clock stop according to PHY capability if
+	 * the platform allows
+	 */
+	if (priv->plat->flags & STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP)
+		priv->tx_lpi_clk_stop = tx_clk_stop;
+
 	stmmac_set_eee_timer(priv, priv->hw, STMMAC_DEFAULT_LIT_LS,
 			     STMMAC_DEFAULT_TWT_LS);
 
 	/* Try to cnfigure the hardware timer. */
 	ret = stmmac_set_lpi_mode(priv, priv->hw, STMMAC_LPI_TIMER,
-				  priv->plat->flags & STMMAC_FLAG_EN_TX_LPI_CLOCKGATING,
-				  priv->tx_lpi_timer);
+				  priv->tx_lpi_clk_stop, priv->tx_lpi_timer);
 
 	if (ret) {
 		/* Hardware timer mode not supported, or value out of range.
@@ -1269,6 +1273,10 @@ static int stmmac_phy_setup(struct stmmac_priv *priv)
 	if (!(priv->plat->flags & STMMAC_FLAG_RX_CLK_RUNS_IN_LPI))
 		priv->phylink_config.eee_rx_clk_stop_enable = true;
 
+	/* Set the default transmit clock stop bit based on the platform glue */
+	priv->tx_lpi_clk_stop = priv->plat->flags &
+				STMMAC_FLAG_EN_TX_LPI_CLOCKGATING;
+
 	mdio_bus_data = priv->plat->mdio_bus_data;
 	if (mdio_bus_data)
 		priv->phylink_config.default_an_inband =
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index b6f03ab12595..c4ec8bb8144e 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -183,7 +183,8 @@ struct dwmac4_addrs {
 #define STMMAC_FLAG_INT_SNAPSHOT_EN		BIT(9)
 #define STMMAC_FLAG_RX_CLK_RUNS_IN_LPI		BIT(10)
 #define STMMAC_FLAG_EN_TX_LPI_CLOCKGATING	BIT(11)
-#define STMMAC_FLAG_HWTSTAMP_CORRECT_LATENCY	BIT(12)
+#define STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP	BIT(12)
+#define STMMAC_FLAG_HWTSTAMP_CORRECT_LATENCY	BIT(13)
 
 struct plat_stmmacenet_data {
 	int bus_id;
-- 
2.30.2

[PATCH net-next v2 2/7] net: stmmac: starfive: use PHY capability for TX clock stop

[Russell King (Oracle)]

Whether the MII transmit clock can be stopped is primarily a property
of the PHY (there is a capability bit that should be checked first.)
Whether the MAC is capable of stopping the transmit clock is a separate
issue, but this is already handled by the core DesignWare MAC code.

Add the flag to allow the stmmac core to use the PHY capability.

Cc: Samin Guo <samin.guo@starfivetech.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
index 5e31cb3bb4b8..2013d7477eb7 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-starfive.c
@@ -124,6 +124,7 @@ static int starfive_dwmac_probe(struct platform_device *pdev)
 		plat_dat->set_clk_tx_rate = stmmac_set_clk_tx_rate;
 
 	dwmac->dev = &pdev->dev;
+	plat_dat->flags |= STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP;
 	plat_dat->bsp_priv = dwmac;
 	plat_dat->dma_cfg->dche = true;
 
-- 
2.30.2

[PATCH net-next v2 3/7] net: stmmac: stm32: use PHY capability for TX clock stop

[Russell King (Oracle)]

Whether the MII transmit clock can be stopped is primarily a property
of the PHY (there is a capability bit that should be checked first.)
Whether the MAC is capable of stopping the transmit clock is a separate
issue, but this is already handled by the core DesignWare MAC code.

Add the flag to allow the stmmac core to use the PHY capability.

Cc: Christophe Roullier <christophe.roullier@st.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
index 1fcb74e9e3ff..c3d321192581 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c
@@ -538,6 +538,7 @@ static int stm32_dwmac_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	plat_dat->flags |= STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP;
 	plat_dat->bsp_priv = dwmac;
 
 	ret = stm32_dwmac_init(plat_dat, false);
-- 
2.30.2

[PATCH net-next v2 4/7] riscv: dts: starfive: remove "snps,en-tx-lpi-clockgating" property

[Russell King (Oracle)]

Whether the MII transmit clock can be stopped is primarily a property
of the PHY (there is a capability bit that should be checked first.)
Whether the MAC is capable of stopping the transmit clock is a separate
issue, but this is already handled by the core DesignWare MAC code.

As commit "net: stmmac: starfive: use PHY capability for TX clock stop"
adds the flag to use the PHY capability, remove the DT property that is
now unecessary.

Cc: Samin Guo <samin.guo@starfivetech.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 arch/riscv/boot/dts/starfive/jh7110.dtsi | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/riscv/boot/dts/starfive/jh7110.dtsi b/arch/riscv/boot/dts/starfive/jh7110.dtsi
index 0d8339357bad..a7aed4a21b65 100644
--- a/arch/riscv/boot/dts/starfive/jh7110.dtsi
+++ b/arch/riscv/boot/dts/starfive/jh7110.dtsi
@@ -1022,7 +1022,6 @@ gmac0: ethernet@16030000 {
 			snps,force_thresh_dma_mode;
 			snps,axi-config = <&stmmac_axi_setup>;
 			snps,tso;
-			snps,en-tx-lpi-clockgating;
 			snps,txpbl = <16>;
 			snps,rxpbl = <16>;
 			starfive,syscon = <&aon_syscon 0xc 0x12>;
@@ -1053,7 +1052,6 @@ gmac1: ethernet@16040000 {
 			snps,force_thresh_dma_mode;
 			snps,axi-config = <&stmmac_axi_setup>;
 			snps,tso;
-			snps,en-tx-lpi-clockgating;
 			snps,txpbl = <16>;
 			snps,rxpbl = <16>;
 			starfive,syscon = <&sys_syscon 0x90 0x2>;
-- 
2.30.2

[PATCH net-next v2 5/7] ARM: dts: stm32: remove "snps,en-tx-lpi-clockgating" property

[Russell King (Oracle)]

Whether the MII transmit clock can be stopped is primarily a property
of the PHY (there is a capability bit that should be checked first.)
Whether the MAC is capable of stopping the transmit clock is a separate
issue, but this is already handled by the core DesignWare MAC code.

As commit "net: stmmac: stm32: use PHY capability for TX clock stop"
adds the flag to use the PHY capability, remove the DT property that is
now unecessary.

Cc: Samin Guo <samin.guo@starfivetech.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 arch/arm/boot/dts/st/stm32mp151.dtsi | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/arm/boot/dts/st/stm32mp151.dtsi b/arch/arm/boot/dts/st/stm32mp151.dtsi
index b9a87fbe971d..0daa8ffe2ff5 100644
--- a/arch/arm/boot/dts/st/stm32mp151.dtsi
+++ b/arch/arm/boot/dts/st/stm32mp151.dtsi
@@ -1781,7 +1781,6 @@ ethernet0: ethernet@5800a000 {
 				st,syscon = <&syscfg 0x4>;
 				snps,mixed-burst;
 				snps,pbl = <2>;
-				snps,en-tx-lpi-clockgating;
 				snps,axi-config = <&stmmac_axi_config_0>;
 				snps,tso;
 				access-controllers = <&etzpc 94>;
-- 
2.30.2

[PATCH net-next v2 6/7] dt-bindings: deprecate "snps,en-tx-lpi-clockgating" property

[Russell King (Oracle)]

Whether the MII transmit clock can be stopped is primarily a property
of the PHY (there is a capability bit that should be checked first.)
Whether the MAC is capable of stopping the transmit clock is a separate
issue, but this is already handled by the core DesignWare MAC code.

Therefore, snps,en-tx-lpi-clockgating is technically incorrect, so this
commit deprecates the property in the binding.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 Documentation/devicetree/bindings/net/snps,dwmac.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/net/snps,dwmac.yaml b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
index 3f0aa46d798e..78b3030dc56d 100644
--- a/Documentation/devicetree/bindings/net/snps,dwmac.yaml
+++ b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
@@ -494,6 +494,7 @@ title: Synopsys DesignWare MAC
 
   snps,en-tx-lpi-clockgating:
     $ref: /schemas/types.yaml#/definitions/flag
+    deprecated: true
     description:
       Enable gating of the MAC TX clock during TX low-power mode
 
-- 
2.30.2

[PATCH net-next v2 7/7] net: stmmac: deprecate "snps,en-tx-lpi-clockgating" property

[Russell King (Oracle)]

Whether the MII transmit clock can be stopped is primarily a property
of the PHY (there is a capability bit that should be checked first.)
Whether the MAC is capable of stopping the transmit clock is a separate
issue, but this is already handled by the core DesignWare MAC code.

Therefore, snps,en-tx-lpi-clockgating is technically incorrect, and
this commit adds a warning should a DT be encountered with the property
present.

However, we keep backwards compatibility.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 8dc3bd6946c6..c73eff6a56b8 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -497,8 +497,11 @@ stmmac_probe_config_dt(struct platform_device *pdev, u8 *mac)
 	plat->force_sf_dma_mode =
 		of_property_read_bool(np, "snps,force_sf_dma_mode");
 
-	if (of_property_read_bool(np, "snps,en-tx-lpi-clockgating"))
+	if (of_property_read_bool(np, "snps,en-tx-lpi-clockgating")) {
+		dev_warn(&pdev->dev,
+			 "OF property snps,en-tx-lpi-clockgating is deprecated, please convert driver to use STMMAC_FLAG_EN_TX_LPI_CLK_PHY_CAP\n");
 		plat->flags |= STMMAC_FLAG_EN_TX_LPI_CLOCKGATING;
+	}
 
 	/* Set the maxmtu to a default of JUMBO_LEN in case the
 	 * parameter is not present in the device tree.
-- 
2.30.2

Re: [PATCH net-next v2 7/7] net: stmmac: deprecate "snps,en-tx-lpi-clockgating" property

[Lad, Prabhakar]

On Wed, Mar 12, 2025 at 9:58 AM Russell King (Oracle)
<rmk+kernel@armlinux.org.uk> wrote:
>
> Whether the MII transmit clock can be stopped is primarily a property
> of the PHY (there is a capability bit that should be checked first.)
> Whether the MAC is capable of stopping the transmit clock is a separate
> issue, but this is already handled by the core DesignWare MAC code.
>
> Therefore, snps,en-tx-lpi-clockgating is technically incorrect, and
> this commit adds a warning should a DT be encountered with the property
> present.
>
> However, we keep backwards compatibility.
>
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> ---
>  drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Cheers,
Prabhakar

Re: [PATCH net-next v2 0/7] net: stmmac: deprecate "snps,en-tx-lpi-clockgating" property

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Wed, 12 Mar 2025 09:34:20 +0000 you wrote:
> On Sun, Mar 09, 2025 at 03:01:45PM +0000, Russell King (Oracle) wrote:
> Hi,
> 
> This series deprecates the "snps,en-tx-lpi-clockgating" property for
> stmmac.
> 
> MII Transmit clock gating, where the MAC hardware supports gating this
> clock, is a function of the connected PHY capabilities, which it
> reports through its status register.
> 
> [...]

Here is the summary with links:
  - [net-next,v2,1/7] net: stmmac: allow platforms to use PHY tx clock stop capability
    https://git.kernel.org/netdev/net-next/c/0c1f1eb65425
  - [net-next,v2,2/7] net: stmmac: starfive: use PHY capability for TX clock stop
    https://git.kernel.org/netdev/net-next/c/5f250bd72a01
  - [net-next,v2,3/7] net: stmmac: stm32: use PHY capability for TX clock stop
    https://git.kernel.org/netdev/net-next/c/a5bc19e2abeb
  - [net-next,v2,4/7] riscv: dts: starfive: remove "snps,en-tx-lpi-clockgating" property
    https://git.kernel.org/netdev/net-next/c/637af286f9fc
  - [net-next,v2,5/7] ARM: dts: stm32: remove "snps,en-tx-lpi-clockgating" property
    https://git.kernel.org/netdev/net-next/c/50a84bbc7ec1
  - [net-next,v2,6/7] dt-bindings: deprecate "snps,en-tx-lpi-clockgating" property
    https://git.kernel.org/netdev/net-next/c/a62b7901d3a9
  - [net-next,v2,7/7] net: stmmac: deprecate "snps,en-tx-lpi-clockgating" property
    https://git.kernel.org/netdev/net-next/c/cf0a96de397e

You are awesome, thank you!
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