net: enetc: update max chained Tx BD number for i.MX95 ENETC

The max chained Tx BDs of latest ENETC (i.MX95 ENETC, rev 4.1) has been
increased to 63, but since the range of MAX_SKB_FRAGS is 17~45, so for
i.MX95 ENETC and later revision, it is better to set ENETC4_MAX_SKB_FRAGS
to MAX_SKB_FRAGS.

In addition, add max_frags in struct enetc_drvdata to indicate the max
chained BDs supported by device. Because the max number of chained BDs
supported by LS1028A and i.MX95 ENETC is different.

Signed-off-by: Wei Fang <[email protected]>
Reviewed-by: Frank Li <[email protected]>
Reviewed-by: Claudiu Manoil <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: Wei Fang

drivers/net/ethernet/freescale/enetc/enetc.c

@@ -534,6 +534,7 @@ static void enetc_tso_complete_csum(struct enetc_bdr *tx_ring, struct tso_t *tso
 
 static int enetc_map_tx_tso_buffs(struct enetc_bdr *tx_ring, struct sk_buff *skb)
 {
+	struct enetc_ndev_priv *priv = netdev_priv(tx_ring->ndev);
 	int hdr_len, total_len, data_len;
 	struct enetc_tx_swbd *tx_swbd;
 	union enetc_tx_bd *txbd;
@@ -599,7 +600,7 @@ static int enetc_map_tx_tso_buffs(struct enetc_bdr *tx_ring, struct sk_buff *skb
 			bd_data_num++;
 			tso_build_data(skb, &tso, size);
 
-			if (unlikely(bd_data_num >= ENETC_MAX_SKB_FRAGS && data_len))
+			if (unlikely(bd_data_num >= priv->max_frags && data_len))
 				goto err_chained_bd;
 		}
 
@@ -660,7 +661,7 @@ static netdev_tx_t enetc_start_xmit(struct sk_buff *skb,
 		count = enetc_map_tx_tso_buffs(tx_ring, skb);
 		enetc_unlock_mdio();
 	} else {
-		if (unlikely(skb_shinfo(skb)->nr_frags > ENETC_MAX_SKB_FRAGS))
+		if (unlikely(skb_shinfo(skb)->nr_frags > priv->max_frags))
 			if (unlikely(skb_linearize(skb)))
 				goto drop_packet_err;
 
@@ -678,7 +679,7 @@ static netdev_tx_t enetc_start_xmit(struct sk_buff *skb,
 	if (unlikely(!count))
 		goto drop_packet_err;
 
-	if (enetc_bd_unused(tx_ring) < ENETC_TXBDS_MAX_NEEDED)
+	if (enetc_bd_unused(tx_ring) < ENETC_TXBDS_MAX_NEEDED(priv->max_frags))
 		netif_stop_subqueue(ndev, tx_ring->index);
 
 	return NETDEV_TX_OK;
@@ -946,7 +947,8 @@ static bool enetc_clean_tx_ring(struct enetc_bdr *tx_ring, int napi_budget)
 	if (unlikely(tx_frm_cnt && netif_carrier_ok(ndev) &&
 		     __netif_subqueue_stopped(ndev, tx_ring->index) &&
 		     !test_bit(ENETC_TX_DOWN, &priv->flags) &&
-		     (enetc_bd_unused(tx_ring) >= ENETC_TXBDS_MAX_NEEDED))) {
+		     (enetc_bd_unused(tx_ring) >=
+		      ENETC_TXBDS_MAX_NEEDED(priv->max_frags)))) {
 		netif_wake_subqueue(ndev, tx_ring->index);
 	}
 
@@ -3307,18 +3309,21 @@ EXPORT_SYMBOL_GPL(enetc_pci_remove);
 static const struct enetc_drvdata enetc_pf_data = {
 	.sysclk_freq = ENETC_CLK_400M,
 	.pmac_offset = ENETC_PMAC_OFFSET,
+	.max_frags = ENETC_MAX_SKB_FRAGS,
 	.eth_ops = &enetc_pf_ethtool_ops,
 };
 
 static const struct enetc_drvdata enetc4_pf_data = {
 	.sysclk_freq = ENETC_CLK_333M,
 	.tx_csum = true,
+	.max_frags = ENETC4_MAX_SKB_FRAGS,
 	.pmac_offset = ENETC4_PMAC_OFFSET,
 	.eth_ops = &enetc4_pf_ethtool_ops,
 };
 
 static const struct enetc_drvdata enetc_vf_data = {
 	.sysclk_freq = ENETC_CLK_400M,
+	.max_frags = ENETC_MAX_SKB_FRAGS,
 	.eth_ops = &enetc_vf_ethtool_ops,
 };
 

drivers/net/ethernet/freescale/enetc/enetc.h

@@ -59,9 +59,16 @@ struct enetc_rx_swbd {
 
 /* ENETC overhead: optional extension BD + 1 BD gap */
 #define ENETC_TXBDS_NEEDED(val)	((val) + 2)
-/* max # of chained Tx BDs is 15, including head and extension BD */
+/* For LS1028A, max # of chained Tx BDs is 15, including head and
+ * extension BD.
+ */
 #define ENETC_MAX_SKB_FRAGS	13
-#define ENETC_TXBDS_MAX_NEEDED	ENETC_TXBDS_NEEDED(ENETC_MAX_SKB_FRAGS + 1)
+/* For ENETC v4 and later versions, max # of chained Tx BDs is 63,
+ * including head and extension BD, but the range of MAX_SKB_FRAGS
+ * is 17 ~ 45, so set ENETC4_MAX_SKB_FRAGS to MAX_SKB_FRAGS.
+ */
+#define ENETC4_MAX_SKB_FRAGS		MAX_SKB_FRAGS
+#define ENETC_TXBDS_MAX_NEEDED(x)	ENETC_TXBDS_NEEDED((x) + 1)
 
 struct enetc_ring_stats {
 	unsigned int packets;
@@ -235,6 +242,7 @@ enum enetc_errata {
 struct enetc_drvdata {
 	u32 pmac_offset; /* Only valid for PSI which supports 802.1Qbu */
 	u8 tx_csum:1;
+	u8 max_frags;
 	u64 sysclk_freq;
 	const struct ethtool_ops *eth_ops;
 };
@@ -377,6 +385,7 @@ struct enetc_ndev_priv {
 	u16 msg_enable;
 
 	u8 preemptible_tcs;
+	u8 max_frags; /* The maximum number of BDs for fragments */
 
 	enum enetc_active_offloads active_offloads;
 

drivers/net/ethernet/freescale/enetc/enetc_pf_common.c

@@ -101,6 +101,7 @@ void enetc_pf_netdev_setup(struct enetc_si *si, struct net_device *ndev,
 
 	priv->msg_enable = (NETIF_MSG_WOL << 1) - 1;
 	priv->sysclk_freq = si->drvdata->sysclk_freq;
+	priv->max_frags = si->drvdata->max_frags;
 	ndev->netdev_ops = ndev_ops;
 	enetc_set_ethtool_ops(ndev);
 	ndev->watchdog_timeo = 5 * HZ;

drivers/net/ethernet/freescale/enetc/enetc_vf.c

@@ -136,6 +136,7 @@ static void enetc_vf_netdev_setup(struct enetc_si *si, struct net_device *ndev,
 
 	priv->msg_enable = (NETIF_MSG_IFUP << 1) - 1;
 	priv->sysclk_freq = si->drvdata->sysclk_freq;
+	priv->max_frags = si->drvdata->max_frags;
 	ndev->netdev_ops = ndev_ops;
 	enetc_set_ethtool_ops(ndev);
 	ndev->watchdog_timeo = 5 * HZ;