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

["Lad, Prabhakar" <prabhakar.csengg@gmail.com>]

On Sun, Mar 9, 2025 at 3:02 PM Russell King (Oracle)
<rmk+kernel@armlinux.org.uk> wrote:
>
> 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.
>
> Cc: "Lad, Prabhakar" <prabhakar.csengg@gmail.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(-)
>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Cheers,
Prabhakar

> 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
>