Merge branch 'net-vertexcom-mse102x-fix-rx-handling'

Stefan Wahren says:

====================
net: vertexcom: mse102x: Fix RX handling

This series is the first part of two series for the Vertexcom driver.
It contains substantial fixes for the RX handling of the Vertexcom MSE102x.
====================

Link: https://patch.msgid.link/20250430133043.7722-1-wahrenst@gmx.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/vertexcom/mse102x.c

@@ -6,6 +6,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/if_vlan.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
@@ -33,7 +34,7 @@
 #define CMD_CTR		(0x2 << CMD_SHIFT)
 
 #define CMD_MASK	GENMASK(15, CMD_SHIFT)
-#define LEN_MASK	GENMASK(CMD_SHIFT - 1, 0)
+#define LEN_MASK	GENMASK(CMD_SHIFT - 2, 0)
 
 #define DET_CMD_LEN	4
 #define DET_SOF_LEN	2
@@ -262,7 +263,7 @@ static int mse102x_tx_frame_spi(struct mse102x_net *mse, struct sk_buff *txp,
 }
 
 static int mse102x_rx_frame_spi(struct mse102x_net *mse, u8 *buff,
-				unsigned int frame_len)
+				unsigned int frame_len, bool drop)
 {
 	struct mse102x_net_spi *mses = to_mse102x_spi(mse);
 	struct spi_transfer *xfer = &mses->spi_xfer;
@@ -280,6 +281,9 @@ static int mse102x_rx_frame_spi(struct mse102x_net *mse, u8 *buff,
 		netdev_err(mse->ndev, "%s: spi_sync() failed: %d\n",
 			   __func__, ret);
 		mse->stats.xfer_err++;
+	} else if (drop) {
+		netdev_dbg(mse->ndev, "%s: Drop frame\n", __func__);
+		ret = -EINVAL;
 	} else if (*sof != cpu_to_be16(DET_SOF)) {
 		netdev_dbg(mse->ndev, "%s: SPI start of frame is invalid (0x%04x)\n",
 			   __func__, *sof);
@@ -307,6 +311,7 @@ static void mse102x_rx_pkt_spi(struct mse102x_net *mse)
 	struct sk_buff *skb;
 	unsigned int rxalign;
 	unsigned int rxlen;
+	bool drop = false;
 	__be16 rx = 0;
 	u16 cmd_resp;
 	u8 *rxpkt;
@@ -329,20 +334,29 @@ static void mse102x_rx_pkt_spi(struct mse102x_net *mse)
 			net_dbg_ratelimited("%s: Unexpected response (0x%04x)\n",
 					    __func__, cmd_resp);
 			mse->stats.invalid_rts++;
-			return;
+			drop = true;
+			goto drop;
 		}
 
 		net_dbg_ratelimited("%s: Unexpected response to first CMD\n",
 				    __func__);
 	}
 
 	rxlen = cmd_resp & LEN_MASK;
-	if (!rxlen) {
-		net_dbg_ratelimited("%s: No frame length defined\n", __func__);
+	if (rxlen < ETH_ZLEN || rxlen > VLAN_ETH_FRAME_LEN) {
+		net_dbg_ratelimited("%s: Invalid frame length: %d\n", __func__,
+				    rxlen);
 		mse->stats.invalid_len++;
-		return;
+		drop = true;
 	}
 
+	/* In case of a invalid CMD_RTS, the frame must be consumed anyway.
+	 * So assume the maximum possible frame length.
+	 */
+drop:
+	if (drop)
+		rxlen = VLAN_ETH_FRAME_LEN;
+
 	rxalign = ALIGN(rxlen + DET_SOF_LEN + DET_DFT_LEN, 4);
 	skb = netdev_alloc_skb_ip_align(mse->ndev, rxalign);
 	if (!skb)
@@ -353,7 +367,7 @@ static void mse102x_rx_pkt_spi(struct mse102x_net *mse)
 	 * They are copied, but ignored.
 	 */
 	rxpkt = skb_put(skb, rxlen) - DET_SOF_LEN;
-	if (mse102x_rx_frame_spi(mse, rxpkt, rxlen)) {
+	if (mse102x_rx_frame_spi(mse, rxpkt, rxlen, drop)) {
 		mse->ndev->stats.rx_errors++;
 		dev_kfree_skb(skb);
 		return;
@@ -509,6 +523,7 @@ static irqreturn_t mse102x_irq(int irq, void *_mse)
 static int mse102x_net_open(struct net_device *ndev)
 {
 	struct mse102x_net *mse = netdev_priv(ndev);
+	struct mse102x_net_spi *mses = to_mse102x_spi(mse);
 	int ret;
 
 	ret = request_threaded_irq(ndev->irq, NULL, mse102x_irq, IRQF_ONESHOT,
@@ -524,6 +539,13 @@ static int mse102x_net_open(struct net_device *ndev)
 
 	netif_carrier_on(ndev);
 
+	/* The SPI interrupt can stuck in case of pending packet(s).
+	 * So poll for possible packet(s) to re-arm the interrupt.
+	 */
+	mutex_lock(&mses->lock);
+	mse102x_rx_pkt_spi(mse);
+	mutex_unlock(&mses->lock);
+
 	netif_dbg(mse, ifup, ndev, "network device up\n");
 
 	return 0;