[PATCH net-next] net: stmmac: mdio: clean up c22/c45 accessor split

[PATCH net-next] net: stmmac: mdio: clean up c22/c45 accessor split

[Russell King (Oracle)]

The C45 accessors were setting the GR (register number) field twice,
once with the 16-bit register address truncated to five bits, and
then overwritten with the C45 devad. This is harmless since the field
was being cleared prior to being updated with the C45 devad, except
for the extra work.

Remove the redundant code.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
Untested, as I don't have my Jetson Xavier NX platform with me (and
probably won't do for a few weeks.)

While this patch has been prepared on top of "net: stmmac: mdio: use
netdev_priv() directly" it shouldn't conflict if that patch is not
applied before this one.

 drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
index 86021e6b67b2..da4542be756a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
@@ -311,12 +311,10 @@ static int stmmac_mdio_read_c45(struct mii_bus *bus, int phyaddr, int devad,
 
 	value |= (phyaddr << priv->hw->mii.addr_shift)
 		& priv->hw->mii.addr_mask;
-	value |= (phyreg << priv->hw->mii.reg_shift) & priv->hw->mii.reg_mask;
 	value |= (priv->clk_csr << priv->hw->mii.clk_csr_shift)
 		& priv->hw->mii.clk_csr_mask;
 	value |= MII_GMAC4_READ;
 	value |= MII_GMAC4_C45E;
-	value &= ~priv->hw->mii.reg_mask;
 	value |= (devad << priv->hw->mii.reg_shift) & priv->hw->mii.reg_mask;
 
 	data |= phyreg << MII_GMAC4_REG_ADDR_SHIFT;
@@ -409,14 +407,12 @@ static int stmmac_mdio_write_c45(struct mii_bus *bus, int phyaddr,
 
 	value |= (phyaddr << priv->hw->mii.addr_shift)
 		& priv->hw->mii.addr_mask;
-	value |= (phyreg << priv->hw->mii.reg_shift) & priv->hw->mii.reg_mask;
 
 	value |= (priv->clk_csr << priv->hw->mii.clk_csr_shift)
 		& priv->hw->mii.clk_csr_mask;
 
 	value |= MII_GMAC4_WRITE;
 	value |= MII_GMAC4_C45E;
-	value &= ~priv->hw->mii.reg_mask;
 	value |= (devad << priv->hw->mii.reg_shift) & priv->hw->mii.reg_mask;
 
 	data |= phyreg << MII_GMAC4_REG_ADDR_SHIFT;
-- 
2.47.2

Re: [PATCH net-next] net: stmmac: mdio: clean up c22/c45 accessor split

[Simon Horman]

On Wed, Aug 27, 2025 at 02:27:47PM +0100, Russell King (Oracle) wrote:
> The C45 accessors were setting the GR (register number) field twice,
> once with the 16-bit register address truncated to five bits, and
> then overwritten with the C45 devad. This is harmless since the field
> was being cleared prior to being updated with the C45 devad, except
> for the extra work.
> 
> Remove the redundant code.
> 
> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
> ---
> Untested, as I don't have my Jetson Xavier NX platform with me (and
> probably won't do for a few weeks.)
> 
> While this patch has been prepared on top of "net: stmmac: mdio: use
> netdev_priv() directly" it shouldn't conflict if that patch is not
> applied before this one.

Reviewed-by: Simon Horman <horms@kernel.org>

Re: [PATCH net-next] net: stmmac: mdio: clean up c22/c45 accessor split

[patchwork-bot+netdevbpf]

Hello:

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

On Wed, 27 Aug 2025 14:27:47 +0100 you wrote:
> The C45 accessors were setting the GR (register number) field twice,
> once with the 16-bit register address truncated to five bits, and
> then overwritten with the C45 devad. This is harmless since the field
> was being cleared prior to being updated with the C45 devad, except
> for the extra work.
> 
> Remove the redundant code.
> 
> [...]

Here is the summary with links:
  - [net-next] net: stmmac: mdio: clean up c22/c45 accessor split
    https://git.kernel.org/netdev/net-next/c/24eb86a8170f

You are awesome, thank you!
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