[PATCH RFC net-next 07/10] net: stmmac: limit MAC .debug() to dwmac1000 and dwmac4

["Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>]

Avoid a bare test against snpsver which has multiple different number
spaces depending on the core type by testing for core types that
implement the .debug() method. This documents that these statistics
are only available on dwmac1000 and dwmac4 cores.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 .../net/ethernet/stmicro/stmmac/stmmac_ethtool.c    | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
index 343cf903c0bf..0caa5b992519 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_ethtool.c
@@ -531,7 +531,10 @@ static void stmmac_get_ethtool_stats(struct net_device *dev,
 		}
 	}
 
-	/* Update the DMA HW counters for dwmac10/100 */
+	/* Update the DMA HW counters for dwmac10/100 (DWMAC_CORE_MAC100),
+	 * where this will return zero. Other core types will have a non-zero
+	 * return value.
+	 */
 	ret = stmmac_dma_diagnostic_fr(priv, &priv->xstats, priv->ioaddr);
 	if (ret) {
 		/* If supported, for new GMAC chips expose the MMC counters */
@@ -553,7 +556,13 @@ static void stmmac_get_ethtool_stats(struct net_device *dev,
 				priv->xstats.phy_eee_wakeup_error_n = val;
 		}
 
-		if (priv->snpsver >= DWMAC_CORE_3_50)
+		/* Only dwmac1000 and dwmac4 implements the MAC .debug() method.
+		 * As there are different version spaces depending on core_type,
+		 * make this conditional on the appropriate core type.
+		 */
+		if ((priv->plat->core_type == DWMAC_CORE_GMAC ||
+		     priv->plat->core_type == DWMAC_CORE_GMAC4) &&
+		    priv->snpsver >= DWMAC_CORE_3_50)
 			stmmac_mac_debug(priv, priv->ioaddr,
 					(void *)&priv->xstats,
 					rx_queues_count, tx_queues_count);
-- 
2.47.3