[PATCH] net: stmmac: disable Split Header (SPH) for Intel platforms

[Tan Tee Min <tee.min.tan@linux.intel.com>]

commit 47f753c1108e287edb3e27fad8a7511a9d55578e upstream.

Based on DesignWare Ethernet QoS datasheet, we are seeing the limitation
of Split Header (SPH) feature is not supported for Ipv4 fragmented packet.
This SPH limitation will cause ping failure when the packets size exceed
the MTU size. For example, the issue happens once the basic ping packet
size is larger than the configured MTU size and the data is lost inside
the fragmented packet, replaced by zeros/corrupted values, and leads to
ping fail.

So, disable the Split Header for Intel platforms.

v2: Add fixes tag in commit message.

Fixes: 67afd6d1cfdf("net: stmmac: Add Split Header support and enable it in XGMAC cores")
Cc: <stable@vger.kernel.org> # 5.4.x
Suggested-by: Ong, Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: Mohammad Athari Bin Ismail <mohammad.athari.ismail@intel.com>
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Signed-off-by: Tan Tee Min <tee.min.tan@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 2 +-
 drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c  | 1 +
 include/linux/stmmac.h                            | 1 +
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 9cbc0179d24e..9931724c4727 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -4531,7 +4531,7 @@ int stmmac_dvr_probe(struct device *device,
 		dev_info(priv->device, "TSO feature enabled\n");
 	}
 
-	if (priv->dma_cap.sphen) {
+	if (priv->dma_cap.sphen && !priv->plat->sph_disable) {
 		ndev->hw_features |= NETIF_F_GRO;
 		priv->sph = true;
 		dev_info(priv->device, "SPH feature enabled\n");
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
index 292045f4581f..d46e3795899f 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
@@ -119,6 +119,7 @@ static int intel_mgbe_common_data(struct pci_dev *pdev,
 	plat->has_gmac4 = 1;
 	plat->force_sf_dma_mode = 0;
 	plat->tso_en = 1;
+	plat->sph_disable = 1;
 
 	plat->rx_sched_algorithm = MTL_RX_ALGORITHM_SP;
 
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index dc60d03c4b60..0b35747c9837 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -179,5 +179,6 @@ struct plat_stmmacenet_data {
 	int mac_port_sel_speed;
 	bool en_tx_lpi_clockgating;
 	int has_xgmac;
+	bool sph_disable;
 };
 #endif
-- 
2.25.1