net: bcmgenet: correct the RBUF_OVFL_CNT and RBUF_ERR_CNT MIB values

The location of the RBUF overflow and error counters has moved between
different version of the GENET MAC.  This commit corrects the driver to
read from the correct locations depending on the version of the GENET
MAC.

Fixes: 1c1008c7 ("net: bcmgenet: add main driver file")
Signed-off-by: NDoug Berger <opendmb@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/genet/bcmgenet.c

 /*
  * Broadcom GENET (Gigabit Ethernet) controller driver
  *
- * Copyright (c) 2014 Broadcom Corporation
+ * Copyright (c) 2014-2017 Broadcom
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -778,8 +778,9 @@ static const struct bcmgenet_stats bcmgenet_gstrings_stats[] = {
 	STAT_GENET_RUNT("rx_runt_bytes", mib.rx_runt_bytes),
 	/* Misc UniMAC counters */
 	STAT_GENET_MISC("rbuf_ovflow_cnt", mib.rbuf_ovflow_cnt,
-			UMAC_RBUF_OVFL_CNT),
-	STAT_GENET_MISC("rbuf_err_cnt", mib.rbuf_err_cnt, UMAC_RBUF_ERR_CNT),
+			UMAC_RBUF_OVFL_CNT_V1),
+	STAT_GENET_MISC("rbuf_err_cnt", mib.rbuf_err_cnt,
+			UMAC_RBUF_ERR_CNT_V1),
 	STAT_GENET_MISC("mdf_err_cnt", mib.mdf_err_cnt, UMAC_MDF_ERR_CNT),
 	STAT_GENET_SOFT_MIB("alloc_rx_buff_failed", mib.alloc_rx_buff_failed),
 	STAT_GENET_SOFT_MIB("rx_dma_failed", mib.rx_dma_failed),
@@ -821,6 +822,45 @@ static void bcmgenet_get_strings(struct net_device *dev, u32 stringset,
 	}
 }
 
+static u32 bcmgenet_update_stat_misc(struct bcmgenet_priv *priv, u16 offset)
+{
+	u16 new_offset;
+	u32 val;
+
+	switch (offset) {
+	case UMAC_RBUF_OVFL_CNT_V1:
+		if (GENET_IS_V2(priv))
+			new_offset = RBUF_OVFL_CNT_V2;
+		else
+			new_offset = RBUF_OVFL_CNT_V3PLUS;
+
+		val = bcmgenet_rbuf_readl(priv,	new_offset);
+		/* clear if overflowed */
+		if (val == ~0)
+			bcmgenet_rbuf_writel(priv, 0, new_offset);
+		break;
+	case UMAC_RBUF_ERR_CNT_V1:
+		if (GENET_IS_V2(priv))
+			new_offset = RBUF_ERR_CNT_V2;
+		else
+			new_offset = RBUF_ERR_CNT_V3PLUS;
+
+		val = bcmgenet_rbuf_readl(priv,	new_offset);
+		/* clear if overflowed */
+		if (val == ~0)
+			bcmgenet_rbuf_writel(priv, 0, new_offset);
+		break;
+	default:
+		val = bcmgenet_umac_readl(priv, offset);
+		/* clear if overflowed */
+		if (val == ~0)
+			bcmgenet_umac_writel(priv, 0, offset);
+		break;
+	}
+
+	return val;
+}
+
 static void bcmgenet_update_mib_counters(struct bcmgenet_priv *priv)
 {
 	int i, j = 0;
@@ -845,10 +885,16 @@ static void bcmgenet_update_mib_counters(struct bcmgenet_priv *priv)
 						  UMAC_MIB_START + j + offset);
 			break;
 		case BCMGENET_STAT_MISC:
-			val = bcmgenet_umac_readl(priv, s->reg_offset);
-			/* clear if overflowed */
-			if (val == ~0)
-				bcmgenet_umac_writel(priv, 0, s->reg_offset);
+			if (GENET_IS_V1(priv)) {
+				val = bcmgenet_umac_readl(priv, s->reg_offset);
+				/* clear if overflowed */
+				if (val == ~0)
+					bcmgenet_umac_writel(priv, 0,
+							     s->reg_offset);
+			} else {
+				val = bcmgenet_update_stat_misc(priv,
+								s->reg_offset);
+			}
 			break;
 		}
 

drivers/net/ethernet/broadcom/genet/bcmgenet.h

 /*
- * Copyright (c) 2014 Broadcom Corporation
+ * Copyright (c) 2014-2017 Broadcom
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -214,7 +214,9 @@ struct bcmgenet_mib_counters {
 #define  MDIO_REG_SHIFT			16
 #define  MDIO_REG_MASK			0x1F
 
-#define UMAC_RBUF_OVFL_CNT		0x61C
+#define UMAC_RBUF_OVFL_CNT_V1		0x61C
+#define RBUF_OVFL_CNT_V2		0x80
+#define RBUF_OVFL_CNT_V3PLUS		0x94
 
 #define UMAC_MPD_CTRL			0x620
 #define  MPD_EN				(1 << 0)
@@ -224,7 +226,9 @@ struct bcmgenet_mib_counters {
 
 #define UMAC_MPD_PW_MS			0x624
 #define UMAC_MPD_PW_LS			0x628
-#define UMAC_RBUF_ERR_CNT		0x634
+#define UMAC_RBUF_ERR_CNT_V1		0x634
+#define RBUF_ERR_CNT_V2			0x84
+#define RBUF_ERR_CNT_V3PLUS		0x98
 #define UMAC_MDF_ERR_CNT		0x638
 #define UMAC_MDF_CTRL			0x650
 #define UMAC_MDF_ADDR			0x654