[U-Boot] [PATCH] net: phy: realtek: Introduce quirk to mark RXC not stoppable

[Joe Hershberger]

On Wed, Jan 23, 2019 at 7:57 AM Carlo Caione <ccaione at baylibre.com> wrote:
>
> When EEE is supported by the PHY and the driver allows it, libphy in the
> kernel is configuring the PHY to stop receiving the xMII clock while it
> is signaling LPI. While this (usually) works fine in the kernel this is
> causing issues in U-Boot when rebooting from the linux kernel with this
> bit set (without having the possibility to reset the PHY) where the PHY
> suddenly stops working.
>
> A new quirk is introduced to unconditionally reset this bit. If the
> quirk is not enabled using the proper configuration symbol, the PHY state
> is not changed.
>
> Signed-off-by: Carlo Caione <ccaione at baylibre.com>

Other than a few nits below,

Acked-by: Joe Hershberger <joe.hershberger at ni.com>

> ---
>
> Hi Joe,
> just an heads up that this patch depends on the MMD helpers patch I
> submitted earlier.
>
> ---
>  drivers/net/phy/Kconfig   | 19 +++++++++++++++++++
>  drivers/net/phy/realtek.c | 19 +++++++++++++++++++
>  2 files changed, 38 insertions(+)
>
> diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
> index 3dc0822d9c..d0dab3014e 100644
> --- a/drivers/net/phy/Kconfig
> +++ b/drivers/net/phy/Kconfig
> @@ -202,6 +202,25 @@ config RTL8211X_PHY_FORCE_MASTER
>
>           If unsure, say N.
>
> +config RTL8211F_PHY_FORCE_EEE_RXC_ON
> +       bool "Ethernet PHY RTL8211F: do not stop receiving the xMII clock during LPI"
> +       depends on PHY_REALTEK
> +       default n
> +       help
> +         The IEEE 802.3az-2010 (EEE) standar provides a protocol to coordinate

Typo: standard

> +         transitions to/from a lower power consumption level (Low Power Idle
> +         mode) based on link utilization. When no packets are being
> +         transmitted, the system goes to Low Power Idle mode to save power.
> +
> +         Under particular circumstances this setting can cause issues where
> +         the PHY is unable to transmit or receive any packet when in LPI mode.
> +         The problem is caused when the PHY is configured to stop receiving
> +         the xMII clock while it is signaling LPI. When not stated otherwise
> +         this bit is set by libphy in the linux kernel.

This seems to be copied from Linux, please update to describe what
happens in U-Boot.

> +
> +         Default n, which means that the PHY state is not changed. To work
> +         around the issues, change this setting to y.
> +
>  config PHY_SMSC
>         bool  "Microchip(SMSC) Ethernet PHYs support"
>
> diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
> index b3e6578df9..fa11696fe2 100644
> --- a/drivers/net/phy/realtek.c
> +++ b/drivers/net/phy/realtek.c
> @@ -12,6 +12,7 @@
>
>  #define PHY_RTL8211x_FORCE_MASTER BIT(1)
>  #define PHY_RTL8211E_PINE64_GIGABIT_FIX BIT(2)
> +#define PHY_RTL8211F_FORCE_EEE_RXC_ON BIT(3)
>
>  #define PHY_AUTONEGOTIATE_TIMEOUT 5000
>
> @@ -75,6 +76,15 @@ static int rtl8211e_probe(struct phy_device *phydev)
>         return 0;
>  }
>
> +static int rtl8211f_probe(struct phy_device *phydev)
> +{
> +#ifdef CONFIG_RTL8211F_PHY_FORCE_EEE_RXC_ON
> +       phydev->flags |= PHY_RTL8211F_FORCE_EEE_RXC_ON;
> +#endif
> +
> +       return 0;
> +}
> +
>  /* RealTek RTL8211x */
>  static int rtl8211x_config(struct phy_device *phydev)
>  {
> @@ -124,6 +134,14 @@ static int rtl8211f_config(struct phy_device *phydev)
>  {
>         u16 reg;
>
> +       if (phydev->flags & PHY_RTL8211F_FORCE_EEE_RXC_ON) {
> +               unsigned int reg;
> +
> +               reg = phy_read_mmd(phydev, MDIO_MMD_PCS, MDIO_CTRL1);
> +               reg &= ~MDIO_PCS_CTRL1_CLKSTOP_EN;
> +               phy_write_mmd(phydev, MDIO_MMD_PCS, MDIO_CTRL1, reg);
> +       }
> +
>         phy_write(phydev, MDIO_DEVAD_NONE, MII_BMCR, BMCR_RESET);
>
>         phy_write(phydev, MDIO_DEVAD_NONE,
> @@ -333,6 +351,7 @@ static struct phy_driver RTL8211F_driver = {
>         .uid = 0x1cc916,
>         .mask = 0xffffff,
>         .features = PHY_GBIT_FEATURES,
> +       .probe = &rtl8211f_probe,
>         .config = &rtl8211f_config,
>         .startup = &rtl8211f_startup,
>         .shutdown = &genphy_shutdown,
> --
> 2.19.1
>
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