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

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;
+}