stmmac: do not discard frame on dribbling bit assert

If this bit is set and the CRC error is reset, then the packet is valid.
Only report this as stat info.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/common.h

@@ -67,6 +67,7 @@ struct stmmac_extra_stats {
 	unsigned long ipc_csum_error;
 	unsigned long rx_collision;
 	unsigned long rx_crc;
+	unsigned long dribbling_bit;
 	unsigned long rx_length;
 	unsigned long rx_mii;
 	unsigned long rx_multicast;

drivers/net/ethernet/stmicro/stmmac/enh_desc.c

@@ -201,7 +201,7 @@ static int enh_desc_get_rx_status(void *data, struct stmmac_extra_stats *x,
 
 	if (unlikely(p->des01.erx.dribbling)) {
 		CHIP_DBG(KERN_ERR "GMAC RX: dribbling error\n");
-		ret = discard_frame;
+		x->dribbling_bit++;
 	}
 	if (unlikely(p->des01.erx.sa_filter_fail)) {
 		CHIP_DBG(KERN_ERR "GMAC RX : Source Address filter fail\n");

drivers/net/ethernet/stmicro/stmmac/norm_desc.c

@@ -104,7 +104,7 @@ static int ndesc_get_rx_status(void *data, struct stmmac_extra_stats *x,
 		ret = discard_frame;
 	}
 	if (unlikely(p->des01.rx.dribbling))
-		ret = discard_frame;
+		x->dribbling_bit++;
 
 	if (unlikely(p->des01.rx.length_error)) {
 		x->rx_length++;

drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c

@@ -47,23 +47,25 @@ struct stmmac_stats {
 	offsetof(struct stmmac_priv, xstats.m)}
 
 static const struct stmmac_stats stmmac_gstrings_stats[] = {
+	/* Transmit errors */
 	STMMAC_STAT(tx_underflow),
 	STMMAC_STAT(tx_carrier),
 	STMMAC_STAT(tx_losscarrier),
 	STMMAC_STAT(vlan_tag),
 	STMMAC_STAT(tx_deferred),
 	STMMAC_STAT(tx_vlan),
-	STMMAC_STAT(rx_vlan),
 	STMMAC_STAT(tx_jabber),
 	STMMAC_STAT(tx_frame_flushed),
 	STMMAC_STAT(tx_payload_error),
 	STMMAC_STAT(tx_ip_header_error),
+	/* Receive errors */
 	STMMAC_STAT(rx_desc),
 	STMMAC_STAT(sa_filter_fail),
 	STMMAC_STAT(overflow_error),
 	STMMAC_STAT(ipc_csum_error),
 	STMMAC_STAT(rx_collision),
 	STMMAC_STAT(rx_crc),
+	STMMAC_STAT(dribbling_bit),
 	STMMAC_STAT(rx_length),
 	STMMAC_STAT(rx_mii),
 	STMMAC_STAT(rx_multicast),
@@ -73,6 +75,8 @@ static const struct stmmac_stats stmmac_gstrings_stats[] = {
 	STMMAC_STAT(sa_rx_filter_fail),
 	STMMAC_STAT(rx_missed_cntr),
 	STMMAC_STAT(rx_overflow_cntr),
+	STMMAC_STAT(rx_vlan),
+	/* Tx/Rx IRQ errors */
 	STMMAC_STAT(tx_undeflow_irq),
 	STMMAC_STAT(tx_process_stopped_irq),
 	STMMAC_STAT(tx_jabber_irq),
@@ -82,6 +86,7 @@ static const struct stmmac_stats stmmac_gstrings_stats[] = {
 	STMMAC_STAT(rx_watchdog_irq),
 	STMMAC_STAT(tx_early_irq),
 	STMMAC_STAT(fatal_bus_error_irq),
+	/* Extra info */
 	STMMAC_STAT(threshold),
 	STMMAC_STAT(tx_pkt_n),
 	STMMAC_STAT(rx_pkt_n),