ravb: Add carrier_counters to struct ravb_hw_info

RZ/G2L E-MAC supports carrier counters.
Add a carrier_counter hw feature bit to struct ravb_hw_info
to add this feature only for RZ/G2L.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/renesas/ravb.h

@@ -196,6 +196,8 @@ enum ravb_reg {
 	MAHR	= 0x05c0,
 	MALR	= 0x05c8,
 	TROCR	= 0x0700,	/* R-Car Gen3 and RZ/G2L only */
+	CXR41	= 0x0708,	/* RZ/G2L only */
+	CXR42	= 0x0710,	/* RZ/G2L only */
 	CEFCR	= 0x0740,
 	FRECR	= 0x0748,
 	TSFRCR	= 0x0750,
@@ -1017,6 +1019,7 @@ struct ravb_hw_info {
 	/* hardware features */
 	unsigned internal_delay:1;	/* AVB-DMAC has internal delays */
 	unsigned tx_counters:1;		/* E-MAC has TX counters */
+	unsigned carrier_counters:1;	/* E-MAC has carrier counters */
 	unsigned multi_irqs:1;		/* AVB-DMAC and E-MAC has multiple irqs */
 	unsigned gptp:1;		/* AVB-DMAC has gPTP support */
 	unsigned ccc_gac:1;		/* AVB-DMAC has gPTP support active in config mode */

drivers/net/ethernet/renesas/ravb_main.c

@@ -2053,6 +2053,13 @@ static struct net_device_stats *ravb_get_stats(struct net_device *ndev)
 		ravb_write(ndev, 0, TROCR);	/* (write clear) */
 	}
 
+	if (info->carrier_counters) {
+		nstats->collisions += ravb_read(ndev, CXR41);
+		ravb_write(ndev, 0, CXR41);	/* (write clear) */
+		nstats->tx_carrier_errors += ravb_read(ndev, CXR42);
+		ravb_write(ndev, 0, CXR42);	/* (write clear) */
+	}
+
 	nstats->rx_packets = stats0->rx_packets;
 	nstats->tx_packets = stats0->tx_packets;
 	nstats->rx_bytes = stats0->rx_bytes;
@@ -2432,6 +2439,7 @@ static const struct ravb_hw_info gbeth_hw_info = {
 	.rx_max_buf_size = SZ_8K,
 	.aligned_tx = 1,
 	.tx_counters = 1,
+	.carrier_counters = 1,
 	.half_duplex = 1,
 };