net: ethernet: ti: cpsw: fix min eth packet size for non-switch use-cases

The CPSW switchdev driver inherited fix from commit 9421c9015047 ("net:
ethernet: ti: cpsw: fix min eth packet size") which changes min TX packet
size to 64bytes (VLAN_ETH_ZLEN, excluding ETH_FCS). It was done to fix HW
packed drop issue when packets are sent from Host to the port with PVID and
un-tagging enabled. Unfortunately this breaks some other non-switch
specific use-cases, like:
- [1] CPSW port as DSA CPU port with DSA-tag applied at the end of the
packet
- [2] Some industrial protocols, which expects min TX packet size 60Bytes
(excluding FCS).

Fix it by configuring min TX packet size depending on driver mode
 - 60Bytes (ETH_ZLEN) for multi mac (dual-mac) mode
 - 64Bytes (VLAN_ETH_ZLEN) for switch mode
and update it during driver mode change and annotate with
READ_ONCE()/WRITE_ONCE() as it can be read by napi while writing.

[1] https://lore.kernel.org/netdev/20210531124051.GA15218@cephalopod/
[2] https://e2e.ti.com/support/arm/sitara_arm/f/791/t/701669

Cc: stable@vger.kernel.org
Fixes: ed3525eda4c4 ("net: ethernet: ti: introduce cpsw switchdev based driver part 1 - dual-emac")
Reported-by: Ben Hutchings <ben.hutchings@essensium.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/ti/cpsw_new.c b/drivers/net/ethernet/ti/cpsw_new.c
index 57d279f..d1d0200 100644 (file)
--- a/drivers/net/ethernet/ti/cpsw_new.c
+++ b/drivers/net/ethernet/ti/cpsw_new.c
@@ -920,7 +920,7 @@ static netdev_tx_t cpsw_ndo_start_xmit(struct sk_buff *skb,
        struct cpdma_chan *txch;
        int ret, q_idx;
 
-       if (skb_padto(skb, CPSW_MIN_PACKET_SIZE)) {
+       if (skb_put_padto(skb, READ_ONCE(priv->tx_packet_min))) {
                cpsw_err(priv, tx_err, "packet pad failed\n");
                ndev->stats.tx_dropped++;
                return NET_XMIT_DROP;
@@ -1100,7 +1100,7 @@ static int cpsw_ndo_xdp_xmit(struct net_device *ndev, int n,
 
        for (i = 0; i < n; i++) {
                xdpf = frames[i];
-               if (xdpf->len < CPSW_MIN_PACKET_SIZE)
+               if (xdpf->len < READ_ONCE(priv->tx_packet_min))
                        break;
 
                if (cpsw_xdp_tx_frame(priv, xdpf, NULL, priv->emac_port))
@@ -1389,6 +1389,7 @@ static int cpsw_create_ports(struct cpsw_common *cpsw)
                priv->dev  = dev;
                priv->msg_enable = netif_msg_init(debug_level, CPSW_DEBUG);
                priv->emac_port = i + 1;
+               priv->tx_packet_min = CPSW_MIN_PACKET_SIZE;
 
                if (is_valid_ether_addr(slave_data->mac_addr)) {
                        ether_addr_copy(priv->mac_addr, slave_data->mac_addr);
@@ -1686,6 +1687,7 @@ static int cpsw_dl_switch_mode_set(struct devlink *dl, u32 id,
 
                        priv = netdev_priv(sl_ndev);
                        slave->port_vlan = vlan;
+                       WRITE_ONCE(priv->tx_packet_min, CPSW_MIN_PACKET_SIZE_VLAN);
                        if (netif_running(sl_ndev))
                                cpsw_port_add_switch_def_ale_entries(priv,
                                                                     slave);
@@ -1714,6 +1716,7 @@ static int cpsw_dl_switch_mode_set(struct devlink *dl, u32 id,
 
                        priv = netdev_priv(slave->ndev);
                        slave->port_vlan = slave->data->dual_emac_res_vlan;
+                       WRITE_ONCE(priv->tx_packet_min, CPSW_MIN_PACKET_SIZE);
                        cpsw_port_add_dual_emac_def_ale_entries(priv, slave);
                }
 

diff --git a/drivers/net/ethernet/ti/cpsw_priv.h b/drivers/net/ethernet/ti/cpsw_priv.h
index a323bea..2951fb7 100644 (file)
--- a/drivers/net/ethernet/ti/cpsw_priv.h
+++ b/drivers/net/ethernet/ti/cpsw_priv.h
@@ -89,7 +89,8 @@ do {                                                          \
 
 #define CPSW_POLL_WEIGHT       64
 #define CPSW_RX_VLAN_ENCAP_HDR_SIZE            4
-#define CPSW_MIN_PACKET_SIZE   (VLAN_ETH_ZLEN)
+#define CPSW_MIN_PACKET_SIZE_VLAN      (VLAN_ETH_ZLEN)
+#define CPSW_MIN_PACKET_SIZE   (ETH_ZLEN)
 #define CPSW_MAX_PACKET_SIZE   (VLAN_ETH_FRAME_LEN +\
                                 ETH_FCS_LEN +\
                                 CPSW_RX_VLAN_ENCAP_HDR_SIZE)
@@ -380,6 +381,7 @@ struct cpsw_priv {
        u32 emac_port;
        struct cpsw_common *cpsw;
        int offload_fwd_mark;
+       u32 tx_packet_min;
 };
 
 #define ndev_to_cpsw(ndev) (((struct cpsw_priv *)netdev_priv(ndev))->cpsw)