Re: [PATCH net-next v6 5/6] net: stmmac: xgmac: Complete FPE support

[Vladimir Oltean <olteanv@gmail.com>]

On Wed, Oct 30, 2024 at 01:36:14PM +0800, Furong Xu wrote:
> +int dwxgmac3_fpe_map_preemption_class(struct net_device *ndev,
> +				      struct netlink_ext_ack *extack, u32 pclass)
> +{
> +	u32 val, offset, count, preemptible_txqs = 0;
> +	struct stmmac_priv *priv = netdev_priv(ndev);
> +	u32 num_tc = ndev->num_tc;

Curiously, struct net_device :: num_tc is s16. Just use netdev_get_num_tc()
and store it as int...

> +
> +	if (!num_tc) {
> +		/* Restore default TC:Queue mapping */
> +		for (u32 i = 0; i < priv->plat->tx_queues_to_use; i++) {
> +			val = readl(priv->ioaddr + XGMAC_MTL_TXQ_OPMODE(i));
> +			writel(u32_replace_bits(val, i, XGMAC_Q2TCMAP),
> +			       priv->ioaddr + XGMAC_MTL_TXQ_OPMODE(i));
> +		}
> +	}
> +
> +	/* Synopsys Databook:
> +	 * "All Queues within a traffic class are selected in a round robin
> +	 * fashion (when packets are available) when the traffic class is
> +	 * selected by the scheduler for packet transmission. This is true for
> +	 * any of the scheduling algorithms."
> +	 */
> +	for (u32 tc = 0; tc < num_tc; tc++) {
> +		count = ndev->tc_to_txq[tc].count;
> +		offset = ndev->tc_to_txq[tc].offset;
> +
> +		if (pclass & BIT(tc))
> +			preemptible_txqs |= GENMASK(offset + count - 1, offset);
> +
> +		for (u32 i = 0; i < count; i++) {
> +			val = readl(priv->ioaddr + XGMAC_MTL_TXQ_OPMODE(offset + i));
> +			writel(u32_replace_bits(val, tc, XGMAC_Q2TCMAP),
> +			       priv->ioaddr + XGMAC_MTL_TXQ_OPMODE(offset + i));
> +		}
> +	}
> +
> +	val = readl(priv->ioaddr + XGMAC_MTL_FPE_CTRL_STS);
> +	writel(u32_replace_bits(val, preemptible_txqs, FPE_MTL_PREEMPTION_CLASS),
> +	       priv->ioaddr + XGMAC_MTL_FPE_CTRL_STS);
> +
> +	return 0;
> +}