net: mediatek: mtk_eth_soc: clear MAC_MCR_FORCE_LINK only when MAC is up

Clearing bit MAC_MCR_FORCE_LINK which forces the link down too early
can result in MAC ending up in a broken/blocked state.

Fix this by handling this bit in the .mac_link_up and .mac_link_down
calls instead of in .mac_finish.

Fixes: b8fc9f30 ("net: ethernet: mediatek: Add basic PHYLINK support")
Suggested-by: Mason-cw Chang <Mason-cw.Chang@mediatek.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -677,8 +677,7 @@ 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_RX_FIFO_CLR_DIS;
+		   MAC_MCR_BACKOFF_EN | MAC_MCR_BACKPR_EN | MAC_MCR_RX_FIFO_CLR_DIS;
 
 	/* Only update control register when needed! */
 	if (mcr_new != mcr_cur)
@@ -694,7 +693,7 @@ static void mtk_mac_link_down(struct phylink_config *config, unsigned int mode,
 					   phylink_config);
 	u32 mcr = mtk_r32(mac->hw, MTK_MAC_MCR(mac->id));
 
-	mcr &= ~(MAC_MCR_TX_EN | MAC_MCR_RX_EN);
+	mcr &= ~(MAC_MCR_TX_EN | MAC_MCR_RX_EN | MAC_MCR_FORCE_LINK);
 	mtk_w32(mac->hw, mcr, MTK_MAC_MCR(mac->id));
 }
 
@@ -803,7 +802,7 @@ static void mtk_mac_link_up(struct phylink_config *config,
 	if (rx_pause)
 		mcr |= MAC_MCR_FORCE_RX_FC;
 
-	mcr |= MAC_MCR_TX_EN | MAC_MCR_RX_EN;
+	mcr |= MAC_MCR_TX_EN | MAC_MCR_RX_EN | MAC_MCR_FORCE_LINK;
 	mtk_w32(mac->hw, mcr, MTK_MAC_MCR(mac->id));
 }