net: ethernet: ti: am65-cpsw: fix tx csum offload for multi mac mode

The current implementation uses .ndo_set_features() callback to track
NETIF_F_HW_CSUM feature changes and update generic
CPSW_P0_CONTROL_REG.RX_CHECKSUM_EN option accordingly. It's not going to
work in case of multi-port devices as TX csum offload can be changed per
netdev.

On K3 CPSWxG devices TX csum offload enabled in the following way:

 - the CPSW_P0_CONTROL_REG.RX_CHECKSUM_EN option enables TX csum offload in
generic and affects all TX DMA channels and packets;

 - corresponding fields in TX DMA descriptor have to be filed properly when
upper layer wants to offload TX csum (skb->ip_summed == CHECKSUM_PARTIAL)
and it's per-packet option.

The Linux Network core is expected to never request TX csum offload if
netdev NETIF_F_HW_CSUM feature is disabled, and, as result, TX DMA
descriptors should not be modified, and per-packet TX csum offload will be
disabled (or enabled) on per-netdev basis. Which, in turn, makes it safe to
enable the CPSW_P0_CONTROL_REG.RX_CHECKSUM_EN option unconditionally.

Hence, fix TX csum offload for multi-port devices by:
 - enabling the CPSW_P0_CONTROL_REG.RX_CHECKSUM_EN option in
am65_cpsw_nuss_common_open() unconditionally
 - and removing .ndo_set_features() callback implementation, which was used
only NETIF_F_HW_CSUM feature update purposes

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 0bc0eec..2aa0c2a 100644 (file)
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -428,9 +428,7 @@ static int am65_cpsw_nuss_common_open(struct am65_cpsw_common *common,
        writel(common->rx_flow_id_base,
               host_p->port_base + AM65_CPSW_PORT0_REG_FLOW_ID_OFFSET);
        /* en tx crc offload */
-       if (features & NETIF_F_HW_CSUM)
-               writel(AM65_CPSW_P0_REG_CTL_RX_CHECKSUM_EN,
-                      host_p->port_base + AM65_CPSW_P0_REG_CTL);
+       writel(AM65_CPSW_P0_REG_CTL_RX_CHECKSUM_EN, host_p->port_base + AM65_CPSW_P0_REG_CTL);
 
        am65_cpsw_nuss_set_p0_ptype(common);
 
@@ -1371,31 +1369,6 @@ static void am65_cpsw_nuss_ndo_get_stats(struct net_device *dev,
        stats->tx_dropped       = dev->stats.tx_dropped;
 }
 
-static int am65_cpsw_nuss_ndo_slave_set_features(struct net_device *ndev,
-                                                netdev_features_t features)
-{
-       struct am65_cpsw_common *common = am65_ndev_to_common(ndev);
-       netdev_features_t changes = features ^ ndev->features;
-       struct am65_cpsw_host *host_p;
-
-       host_p = am65_common_get_host(common);
-
-       if (changes & NETIF_F_HW_CSUM) {
-               bool enable = !!(features & NETIF_F_HW_CSUM);
-
-               dev_info(common->dev, "Turn %s tx-checksum-ip-generic\n",
-                        enable ? "ON" : "OFF");
-               if (enable)
-                       writel(AM65_CPSW_P0_REG_CTL_RX_CHECKSUM_EN,
-                              host_p->port_base + AM65_CPSW_P0_REG_CTL);
-               else
-                       writel(0,
-                              host_p->port_base + AM65_CPSW_P0_REG_CTL);
-       }
-
-       return 0;
-}
-
 static const struct net_device_ops am65_cpsw_nuss_netdev_ops_2g = {
        .ndo_open               = am65_cpsw_nuss_ndo_slave_open,
        .ndo_stop               = am65_cpsw_nuss_ndo_slave_stop,
@@ -1408,7 +1381,6 @@ static const struct net_device_ops am65_cpsw_nuss_netdev_ops_2g = {
        .ndo_vlan_rx_add_vid    = am65_cpsw_nuss_ndo_slave_add_vid,
        .ndo_vlan_rx_kill_vid   = am65_cpsw_nuss_ndo_slave_kill_vid,
        .ndo_do_ioctl           = am65_cpsw_nuss_ndo_slave_ioctl,
-       .ndo_set_features       = am65_cpsw_nuss_ndo_slave_set_features,
        .ndo_setup_tc           = am65_cpsw_qos_ndo_setup_tc,
 };