linux-kernel - Re: [PATCH net 1/4] net: stmmac: Apply half-duplex-less constraint for DW QoS Eth only

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Date: Tue, 16 Apr 2024 09:39:20 +0200 (CEST)
From: Romain Gantois <romain.gantois@...tlin.com>
To: Serge Semin <fancer.lancer@...il.com>
cc: Alexandre Torgue <alexandre.torgue@...s.st.com>, 
    Jose Abreu <joabreu@...opsys.com>, "David S. Miller" <davem@...emloft.net>, 
    Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, 
    Paolo Abeni <pabeni@...hat.com>, Russell King <linux@...linux.org.uk>, 
    Yanteng Si <siyanteng@...ngson.cn>, 
    Maxime Coquelin <mcoquelin.stm32@...il.com>, 
    Bhadram Varka <vbhadram@...dia.com>, Simon Horman <horms@...nel.org>, 
    Huacai Chen <chenhuacai@...nel.org>, Chen-Yu Tsai <wens@...e.org>, 
    Jernej Skrabec <jernej.skrabec@...il.com>, 
    Samuel Holland <samuel@...lland.org>, netdev@...r.kernel.org, 
    linux-stm32@...md-mailman.stormreply.com, 
    linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev, 
    linux-kernel@...r.kernel.org
Subject: Re: [PATCH net 1/4] net: stmmac: Apply half-duplex-less constraint
 for DW QoS Eth only

On Fri, 12 Apr 2024, Serge Semin wrote:

> There are three DW MAC IP-cores which can have the multiple Tx/Rx queues
> enabled:
> DW GMAC v3.7+ with AV feature,
> DW QoS Eth v4.x/v5.x,
> DW XGMAC/XLGMAC
> Based on the respective HW databooks, only the DW QoS Eth IP-core doesn't
> support the half-duplex link mode in case if more than one queues enabled:
> 
> "In multiple queue/channel configurations, for half-duplex operation,
> enable only the Q0/CH0 on Tx and Rx. For single queue/channel in
> full-duplex operation, any queue/channel can be enabled."
> 
> The rest of the IP-cores don't have such constraint. Thus in order to have
> the constraint applied for the DW QoS Eth MACs only, let's move the it'
> implementation to the respective MAC-capabilities getter and make sure the
> getter is called in the queues re-init procedure.
> 
> Fixes: b6cfffa7ad92 ("stmmac: fix DMA channel hang in half-duplex mode")
> Signed-off-by: Serge Semin <fancer.lancer@...il.com>
> ---
>  .../net/ethernet/stmicro/stmmac/dwmac4_core.c |  7 +++++++
>  .../net/ethernet/stmicro/stmmac/stmmac_main.c | 19 +++----------------
>  2 files changed, 10 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
> index cef25efbdff9..ec6a13e644b3 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
> @@ -71,6 +71,13 @@ static void dwmac4_core_init(struct mac_device_info *hw,
>  static void dwmac4_phylink_get_caps(struct stmmac_priv *priv)
>  {
>  	priv->phylink_config.mac_capabilities |= MAC_2500FD;
> +
> +	if (priv->plat->tx_queues_to_use > 1)
> +		priv->phylink_config.mac_capabilities &=
> +			~(MAC_10HD | MAC_100HD | MAC_1000HD);
> +	else
> +		priv->phylink_config.mac_capabilities |=
> +			(MAC_10HD | MAC_100HD | MAC_1000HD);
>  }
>  
>  static void dwmac4_rx_queue_enable(struct mac_device_info *hw,
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 24cd80490d19..dd58c21b53ee 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -1198,17 +1198,6 @@ static int stmmac_init_phy(struct net_device *dev)
>  	return ret;
>  }
>  
> -static void stmmac_set_half_duplex(struct stmmac_priv *priv)
> -{
> -	/* Half-Duplex can only work with single tx queue */
> -	if (priv->plat->tx_queues_to_use > 1)
> -		priv->phylink_config.mac_capabilities &=
> -			~(MAC_10HD | MAC_100HD | MAC_1000HD);
> -	else
> -		priv->phylink_config.mac_capabilities |=
> -			(MAC_10HD | MAC_100HD | MAC_1000HD);
> -}
> -
>  static int stmmac_phy_setup(struct stmmac_priv *priv)
>  {
>  	struct stmmac_mdio_bus_data *mdio_bus_data;
> @@ -1237,10 +1226,7 @@ static int stmmac_phy_setup(struct stmmac_priv *priv)
>  				    priv->phylink_config.supported_interfaces);
>  
>  	priv->phylink_config.mac_capabilities = MAC_ASYM_PAUSE | MAC_SYM_PAUSE |
> -						MAC_10FD | MAC_100FD |
> -						MAC_1000FD;
> -
> -	stmmac_set_half_duplex(priv);
> +						MAC_10 | MAC_100 | MAC_1000;
>  
>  	/* Get the MAC specific capabilities */
>  	stmmac_mac_phylink_get_caps(priv);
> @@ -7355,7 +7341,8 @@ int stmmac_reinit_queues(struct net_device *dev, u32 rx_cnt, u32 tx_cnt)
>  			priv->rss.table[i] = ethtool_rxfh_indir_default(i,
>  									rx_cnt);
>  
> -	stmmac_set_half_duplex(priv);
> +	stmmac_mac_phylink_get_caps(priv);
> +
>  	stmmac_napi_add(dev);
>  
>  	if (netif_running(dev))
> -- 
> 2.43.0
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

Reviewed-by: Romain Gantois <romain.gantois@...tlin.com>

Thanks,

-- 
Romain Gantois, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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