[PATCH AUTOSEL 5.10 026/217] net: ethernet: ti: am65-cpsw: fix tx csum offload for multi mac mode

Sasha Levin
2020-12-23T03:13:05Z

From: Grygorii Strashko <grygorii.strashko@ti.com>

[ Upstream commit 97067aaf127487788a297267dede0008cd75bb7b ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/ti/am65-cpsw-nuss.c | 30 +-----------------------
1 file changed, 1 insertion(+), 29 deletions(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 501d676fd88b9..9c359570178c1 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -426,9 +426,7 @@ 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);

@@ -1369,31 +1367,6 @@ 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,
@@ -1406,7 +1379,6 @@ 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,
};

--
2.27.0