openwrt/target/linux/generic/backport-5.15/729-06-v6.1-net-ethernet-mtk_eth_soc-do-not-overwrite-mtu-config.patch

From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: Thu, 17 Nov 2022 00:35:04 +0100
Subject: [PATCH] net: ethernet: mtk_eth_soc: do not overwrite mtu
 configuration running reset routine

Restore user configured MTU running mtk_hw_init() during tx timeout routine
since it will be overwritten after a hw reset.

Reported-by: Felix Fietkau <nbd@nbd.name>
Fixes: 9ea4d311509f ("net: ethernet: mediatek: add the whole ethernet reset into the reset process")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -3176,6 +3176,30 @@ static void mtk_dim_tx(struct work_struc
 	dim->state = DIM_START_MEASURE;
 }
 
+static void mtk_set_mcr_max_rx(struct mtk_mac *mac, u32 val)
+{
+	struct mtk_eth *eth = mac->hw;
+	u32 mcr_cur, mcr_new;
+
+	if (MTK_HAS_CAPS(eth->soc->caps, MTK_SOC_MT7628))
+		return;
+
+	mcr_cur = mtk_r32(mac->hw, MTK_MAC_MCR(mac->id));
+	mcr_new = mcr_cur & ~MAC_MCR_MAX_RX_MASK;
+
+	if (val <= 1518)
+		mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_1518);
+	else if (val <= 1536)
+		mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_1536);
+	else if (val <= 1552)
+		mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_1552);
+	else
+		mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_2048);
+
+	if (mcr_new != mcr_cur)
+		mtk_w32(mac->hw, mcr_new, MTK_MAC_MCR(mac->id));
+}
+
 static int mtk_hw_init(struct mtk_eth *eth)
 {
 	u32 dma_mask = ETHSYS_DMA_AG_MAP_PDMA | ETHSYS_DMA_AG_MAP_QDMA |
@@ -3250,8 +3274,16 @@ static int mtk_hw_init(struct mtk_eth *e
 	 * up with the more appropriate value when mtk_mac_config call is being
 	 * invoked.
 	 */
-	for (i = 0; i < MTK_MAC_COUNT; i++)
+	for (i = 0; i < MTK_MAC_COUNT; i++) {
+		struct net_device *dev = eth->netdev[i];
+
 		mtk_w32(eth, MAC_MCR_FORCE_LINK_DOWN, MTK_MAC_MCR(i));
+		if (dev) {
+			struct mtk_mac *mac = netdev_priv(dev);
+
+			mtk_set_mcr_max_rx(mac, dev->mtu + MTK_RX_ETH_HLEN);
+		}
+	}
 
 	/* Indicates CDM to parse the MTK special tag from CPU
 	 * which also is working out for untag packets.
@@ -3367,7 +3399,6 @@ static int mtk_change_mtu(struct net_dev
 	int length = new_mtu + MTK_RX_ETH_HLEN;
 	struct mtk_mac *mac = netdev_priv(dev);
 	struct mtk_eth *eth = mac->hw;
-	u32 mcr_cur, mcr_new;
 
 	if (rcu_access_pointer(eth->prog) &&
 	    length > MTK_PP_MAX_BUF_SIZE) {
@@ -3375,23 +3406,7 @@ static int mtk_change_mtu(struct net_dev
 		return -EINVAL;
 	}
 
-	if (!MTK_HAS_CAPS(eth->soc->caps, MTK_SOC_MT7628)) {
-		mcr_cur = mtk_r32(mac->hw, MTK_MAC_MCR(mac->id));
-		mcr_new = mcr_cur & ~MAC_MCR_MAX_RX_MASK;
-
-		if (length <= 1518)
-			mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_1518);
-		else if (length <= 1536)
-			mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_1536);
-		else if (length <= 1552)
-			mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_1552);
-		else
-			mcr_new |= MAC_MCR_MAX_RX(MAC_MCR_MAX_RX_2048);
-
-		if (mcr_new != mcr_cur)
-			mtk_w32(mac->hw, mcr_new, MTK_MAC_MCR(mac->id));
-	}
-
+	mtk_set_mcr_max_rx(mac, length);
 	dev->mtu = new_mtu;
 
 	return 0;