Re: [PATCH net-next v21 2/3] net: phy: Add support for Template Control register for PMA

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] UAPI: kernel-internal GENMASK breaks userspace build
- [Low] phy-c45: genphy_c45_template_testmode() returns -EOPNOTSUPP for invalid argument
--

commit 188b76c25d65c5d40038c12ea01f1d6261994387
Author: Kyle Switch <kyle.switch@motor-comm.com>

net: phy: Add support for Template Control register for PMA
    
This commit adds support for the 10GBASE-T PMA Template Test Mode register
field. This allows selecting test modes used for PHY validation.

> diff --git a/drivers/net/phy/phy-c45.c b/drivers/net/phy/phy-c45.c
> index 870920311f9a0..c5f5753f7194b 100644
> --- a/drivers/net/phy/phy-c45.c
> +++ b/drivers/net/phy/phy-c45.c

[ ... ]

> @@ -1408,6 +1408,29 @@ int genphy_c45_fast_retrain(struct phy_device *phydev, bool enable)
>  }
>  EXPORT_SYMBOL_GPL(genphy_c45_fast_retrain);
>  
> +/**
> + * genphy_c45_template_testmode - configure template testmode registers
> + * @phydev: target phy_device struct
> + * @test_mode: testmode includes Normal to Test mode 7
> + *
> + * Description: Set template testmode include Normal to Test mode 7
> + *
> + * Return: 0 on success, or a negative error code on failure (e.g. register
> + * read/write error).
> + */
> +int genphy_c45_template_testmode(struct phy_device *phydev, u16 test_mode)
> +{
> +	u16 ctrl;
> +
> +	if (test_mode > MDIO_PMA_10GBT_TESTMODE_7)
> +		return -EOPNOTSUPP;

[Severity: Low]
Does this return the correct error code? 

Returning -EOPNOTSUPP usually implies that the hardware lacks the capability.
Would it be better to return -EINVAL here to indicate that the caller passed
an out-of-bounds test_mode parameter?

> +
> +	ctrl = FIELD_PREP(MDIO_PMA_10GBT_TESTMODE_MASK, test_mode);
> +	return phy_modify_mmd(phydev, MDIO_MMD_PMAPMD, MDIO_PMA_10GBT_TESTMODE,
> +			      MDIO_PMA_10GBT_TESTMODE_MASK, ctrl);
> +}
> +EXPORT_SYMBOL_GPL(genphy_c45_template_testmode);

> diff --git a/include/uapi/linux/mdio.h b/include/uapi/linux/mdio.h
> index 06f4bc3c20c71..353ca13c64fca 100644
> --- a/include/uapi/linux/mdio.h
> +++ b/include/uapi/linux/mdio.h

[ ... ]

> @@ -320,6 +321,17 @@
>  /* PMA 10GBASE-R Fast Retrain status and control register. */
>  #define MDIO_PMA_10GBR_FSRT_ENABLE	0x0001	/* Fast retrain enable */
>  
> +/* PMA 10GBASE-T Template Test Mode Register*/
> +#define MDIO_PMA_10GBT_TESTMODE_MASK GENMASK(15, 13) /* Template test mode */

[Severity: Medium]
Can this cause compilation failures for userspace programs?

The GENMASK macro is kernel-internal and isn't exported to standard userspace
headers, which typically only expose __GENMASK. Including GENMASK in a UAPI
header might break builds for any userspace applications that include
linux/mdio.h and evaluate this macro.

> +#define MDIO_PMA_10GBT_TESTMODE_NORMAL 0x0 /* Template Normal */
> +#define MDIO_PMA_10GBT_TESTMODE_1 0x1 /* Template TestMode1 */

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260924075048.4060414-1-kyle.switch@motor-comm.com?part=2