In order to mask off the bits, we need to use the '~' operator to invert
all the bits of _MASK and clear them.

Fixes: 48863ce5940f ("stmmac: add DMA support for GMAC 4.xx")

Signed-off-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
index e0165358c4ac..4e1b1bd98f68 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
@@ -266,7 +266,7 @@ static void dwmac4_dma_rx_chan_op_mode(struct stmmac_priv *priv,
 	} else {
 		pr_debug("GMAC: disable RX SF mode (threshold %d)\n", mode);
 		mtl_rx_op &= ~MTL_OP_MODE_RSF;
-		mtl_rx_op &= MTL_OP_MODE_RTC_MASK;
+		mtl_rx_op &= ~MTL_OP_MODE_RTC_MASK;
 		if (mode <= 32)
 			mtl_rx_op |= MTL_OP_MODE_RTC_32;
 		else if (mode <= 64)
@@ -335,7 +335,7 @@ static void dwmac4_dma_tx_chan_op_mode(struct stmmac_priv *priv,
 	} else {
 		pr_debug("GMAC: disabling TX SF (threshold %d)\n", mode);
 		mtl_tx_op &= ~MTL_OP_MODE_TSF;
-		mtl_tx_op &= MTL_OP_MODE_TTC_MASK;
+		mtl_tx_op &= ~MTL_OP_MODE_TTC_MASK;
 		/* Set the transmit threshold */
 		if (mode <= 32)
 			mtl_tx_op |= MTL_OP_MODE_TTC_32;
-- 
2.34.1