net: stmmac: Add Frame Preemption support using TAPRIO API

Adds the support for Frame Preemption using TAPRIO API. This works along
with EST feature and allows to select if preemptable traffic shall be
sent during specific queues opening time.
Signed-off-by: Jose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/common.h

@@ -367,6 +367,7 @@ struct dma_features {
 	unsigned int estwid;
 	unsigned int estdep;
 	unsigned int estsel;
+	unsigned int fpesel;
 };
 
 /* GMAC TX FIFO is 8K, Rx FIFO is 16K */

drivers/net/ethernet/stmicro/stmmac/hwif.h

@@ -376,6 +376,8 @@ struct stmmac_ops {
 	void (*set_arp_offload)(struct mac_device_info *hw, bool en, u32 addr);
 	int (*est_configure)(void __iomem *ioaddr, struct stmmac_est *cfg,
 			     unsigned int ptp_rate);
+	void (*fpe_configure)(void __iomem *ioaddr, u32 num_txq, u32 num_rxq,
+			      bool enable);
 };
 
 #define stmmac_core_init(__priv, __args...) \
@@ -464,6 +466,8 @@ struct stmmac_ops {
 	stmmac_do_void_callback(__priv, mac, set_arp_offload, __args)
 #define stmmac_est_configure(__priv, __args...) \
 	stmmac_do_callback(__priv, mac, est_configure, __args)
+#define stmmac_fpe_configure(__priv, __args...) \
+	stmmac_do_void_callback(__priv, mac, fpe_configure, __args)
 
 /* PTP and HW Timer helpers */
 struct stmmac_hwtimestamp {

drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c

@@ -597,6 +597,7 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
 	u32 size, wid = priv->dma_cap.estwid, dep = priv->dma_cap.estdep;
 	struct plat_stmmacenet_data *plat = priv->plat;
 	struct timespec64 time;
+	bool fpe = false;
 	int i, ret = 0;
 
 	if (!priv->dma_cap.estsel)
@@ -667,8 +668,23 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
 			return -ERANGE;
 		if (gates > GENMASK(31 - wid, 0))
 			return -ERANGE;
-		if (qopt->entries[i].command != TC_TAPRIO_CMD_SET_GATES)
+
+		switch (qopt->entries[i].command) {
+		case TC_TAPRIO_CMD_SET_GATES:
+			if (fpe)
+				return -EINVAL;
+			break;
+		case TC_TAPRIO_CMD_SET_AND_HOLD:
+			gates |= BIT(0);
+			fpe = true;
+			break;
+		case TC_TAPRIO_CMD_SET_AND_RELEASE:
+			gates &= ~BIT(0);
+			fpe = true;
+			break;
+		default:
 			return -EOPNOTSUPP;
+		}
 
 		priv->plat->est->gcl[i] = delta_ns | (gates << wid);
 	}
@@ -681,6 +697,17 @@ static int tc_setup_taprio(struct stmmac_priv *priv,
 	priv->plat->est->ctr[0] = (u32)(qopt->cycle_time % NSEC_PER_SEC);
 	priv->plat->est->ctr[1] = (u32)(qopt->cycle_time / NSEC_PER_SEC);
 
+	if (fpe && !priv->dma_cap.fpesel)
+		return -EOPNOTSUPP;
+
+	ret = stmmac_fpe_configure(priv, priv->ioaddr,
+				   priv->plat->tx_queues_to_use,
+				   priv->plat->rx_queues_to_use, fpe);
+	if (ret && fpe) {
+		netdev_err(priv->dev, "failed to enable Frame Preemption\n");
+		return ret;
+	}
+
 	ret = stmmac_est_configure(priv, priv->ioaddr, priv->plat->est,
 				   priv->plat->clk_ptp_rate);
 	if (ret) {