Re: [PATCH net v3] net: stmmac: Set MAC's flow control register to reflect current settings

[Alexander Lobakin <alexandr.lobakin@intel.com>]

From: "Goh, Wei Sheng" <wei.sheng.goh@intel.com>
Date: Wed, 23 Nov 2022 17:15:29 +0800

> Currently, pause frame register GMAC_RX_FLOW_CTRL_RFE is not updated
> correctly when 'ethtool -A <IFACE> autoneg off rx off tx off' command
> is issued. This fix ensures the flow control change is reflected directly
> in the GMAC_RX_FLOW_CTRL_RFE register.
> 
> Fixes: 46f69ded988d ("net: stmmac: Use resolved link config in mac_link_up()")
> Cc: <stable@vger.kernel.org> # 5.10.x
> Signed-off-by: Goh, Wei Sheng <wei.sheng.goh@intel.com>
> Signed-off-by: Noor Azura Ahmad Tarmizi <noor.azura.ahmad.tarmizi@intel.com>
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> ---
> V2 -> V3: Removed value assign for 'flow' in else statement based on review comments
> V1 -> V2: Removed needless condition based on review comments
> 
>  drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c |  2 ++
>  drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 12 ++++++++++--
>  2 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
> index c25bfecb4a2d..369db308b1dd 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
> @@ -748,6 +748,8 @@ static void dwmac4_flow_ctrl(struct mac_device_info *hw, unsigned int duplex,
>  	if (fc & FLOW_RX) {
>  		pr_debug("\tReceive Flow-Control ON\n");
>  		flow |= GMAC_RX_FLOW_CTRL_RFE;
> +	} else {
> +		pr_debug("\tReceive Flow-Control OFF\n");

Doesn't belong the commit subject. Debug improvements usually are
-next material.
Also, don't use pr_*() when netdev_*(), pci_*() or dev_*() are
available. You won't understand which interface wrote this to the
kernel log currently.

>  	}
>  	writel(flow, ioaddr + GMAC_RX_FLOW_CTRL);
>  
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 8273e6a175c8..ab7f48f32f5b 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -1061,8 +1061,16 @@ static void stmmac_mac_link_up(struct phylink_config *config,
>  		ctrl |= priv->hw->link.duplex;
>  
>  	/* Flow Control operation */
> -	if (tx_pause && rx_pause)
> -		stmmac_mac_flow_ctrl(priv, duplex);
> +	if (rx_pause && tx_pause)
> +		priv->flow_ctrl = FLOW_AUTO;
> +	else if (rx_pause && !tx_pause)
> +		priv->flow_ctrl = FLOW_RX;
> +	else if (!rx_pause && tx_pause)
> +		priv->flow_ctrl = FLOW_TX;
> +	else
> +		priv->flow_ctrl = FLOW_OFF;

	priv->flow_ctrl = FLOW_OFF;
	if (rx_pause)
		priv->flow_ctrl |= FLOW_RX;
	if (tx_pause)
		priv->flow_ctrl |= FLOW_TX;

100% identical functionally.

> +
> +	stmmac_mac_flow_ctrl(priv, duplex);
>  
>  	if (ctrl != old_ctrl)
>  		writel(ctrl, priv->ioaddr + MAC_CTRL_REG);
> -- 
> 2.17.1

Thanks,
Olek