From: Daniel Golle daniel@makrotopia.org
[ Upstream commit 193250ace270fecd586dd2d0dfbd9cbd2ade977f ]
Fix data corruption issue with SerDes connected PHYs operating at 1.25 Gbps speed where we could previously observe about 30% packet loss while the bad packet counter was increasing.
As almost all boards with MediaTek MT7622 or MT7986 use either the MT7531 switch IC operating at 3.125Gbps SerDes rate or single-port PHYs using rate-adaptation to 2500Base-X mode, this issue only got exposed now when we started trying to use SFP modules operating with 1.25 Gbps with the BananaPi R3 board.
The fix is to set bit 12 which disables the RX FIFO clear function when setting up MAC MCR, MediaTek SDK did the same change stating: "If without this patch, kernel might receive invalid packets that are corrupted by GMAC."[1]
[1]: https://git01.mediatek.com/plugins/gitiles/openwrt/feeds/mtk-openwrt-feeds/+...
Fixes: 42c03844e93d ("net-next: mediatek: add support for MediaTek MT7622 SoC") Tested-by: Bjørn Mork bjorn@mork.no Signed-off-by: Daniel Golle daniel@makrotopia.org Reviewed-by: Vladimir Oltean olteanv@gmail.com Reviewed-by: Florian Fainelli f.fainelli@gmail.com Link: https://lore.kernel.org/r/138da2735f92c8b6f8578ec2e5a794ee515b665f.167793731... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mediatek/mtk_eth_soc.c | 3 ++- drivers/net/ethernet/mediatek/mtk_eth_soc.h | 1 + 2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c index e3123723522e3..332329cb1ee00 100644 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c @@ -566,7 +566,8 @@ static int mtk_mac_finish(struct phylink_config *config, unsigned int mode, mcr_cur = mtk_r32(mac->hw, MTK_MAC_MCR(mac->id)); mcr_new = mcr_cur; mcr_new |= MAC_MCR_IPG_CFG | MAC_MCR_FORCE_MODE | - MAC_MCR_BACKOFF_EN | MAC_MCR_BACKPR_EN | MAC_MCR_FORCE_LINK; + MAC_MCR_BACKOFF_EN | MAC_MCR_BACKPR_EN | MAC_MCR_FORCE_LINK | + MAC_MCR_RX_FIFO_CLR_DIS;
/* Only update control register when needed! */ if (mcr_new != mcr_cur) diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h index 2d9186d32bc09..b481d0d46bb16 100644 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h @@ -383,6 +383,7 @@ #define MAC_MCR_FORCE_MODE BIT(15) #define MAC_MCR_TX_EN BIT(14) #define MAC_MCR_RX_EN BIT(13) +#define MAC_MCR_RX_FIFO_CLR_DIS BIT(12) #define MAC_MCR_BACKOFF_EN BIT(9) #define MAC_MCR_BACKPR_EN BIT(8) #define MAC_MCR_FORCE_RX_FC BIT(5)