net: airoha: Move min/max packet len configuration in airoha_dev_open()

In order to align max allowed packet size to the configured mtu, move
REG_GDM_LEN_CFG configuration in airoha_dev_open routine.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250304-airoha-eth-rx-sg-v1-1-283ebc61120e@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: LorenzoBianconi

drivers/net/ethernet/airoha/airoha_eth.c

@@ -138,15 +138,10 @@ static void airoha_fe_maccr_init(struct airoha_eth *eth)
 {
 	int p;
 
-	for (p = 1; p <= ARRAY_SIZE(eth->ports); p++) {
+	for (p = 1; p <= ARRAY_SIZE(eth->ports); p++)
 		airoha_fe_set(eth, REG_GDM_FWD_CFG(p),
 			      GDM_TCP_CKSUM | GDM_UDP_CKSUM | GDM_IP4_CKSUM |
 			      GDM_DROP_CRC_ERR);
-		airoha_fe_rmw(eth, REG_GDM_LEN_CFG(p),
-			      GDM_SHORT_LEN_MASK | GDM_LONG_LEN_MASK,
-			      FIELD_PREP(GDM_SHORT_LEN_MASK, 60) |
-			      FIELD_PREP(GDM_LONG_LEN_MASK, 4004));
-	}
 
 	airoha_fe_rmw(eth, REG_CDM1_VLAN_CTRL, CDM1_VLAN_MASK,
 		      FIELD_PREP(CDM1_VLAN_MASK, 0x8100));
@@ -1520,9 +1515,9 @@ static void airoha_update_hw_stats(struct airoha_gdm_port *port)
 
 static int airoha_dev_open(struct net_device *dev)
 {
+	int err, len = ETH_HLEN + dev->mtu + ETH_FCS_LEN;
 	struct airoha_gdm_port *port = netdev_priv(dev);
 	struct airoha_qdma *qdma = port->qdma;
-	int err;
 
 	netif_tx_start_all_queues(dev);
 	err = airoha_set_vip_for_gdm_port(port, true);
@@ -1536,6 +1531,11 @@ static int airoha_dev_open(struct net_device *dev)
 		airoha_fe_clear(qdma->eth, REG_GDM_INGRESS_CFG(port->id),
 				GDM_STAG_EN_MASK);
 
+	airoha_fe_rmw(qdma->eth, REG_GDM_LEN_CFG(port->id),
+		      GDM_SHORT_LEN_MASK | GDM_LONG_LEN_MASK,
+		      FIELD_PREP(GDM_SHORT_LEN_MASK, 60) |
+		      FIELD_PREP(GDM_LONG_LEN_MASK, len));
+
 	airoha_qdma_set(qdma, REG_QDMA_GLOBAL_CFG,
 			GLOBAL_CFG_TX_DMA_EN_MASK |
 			GLOBAL_CFG_RX_DMA_EN_MASK);