net: ethernet: stmmac: dwmac-sun8i: Enable control of loopback

This patch enable use of set_mac_loopback in dwmac-sun8i
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c

@@ -986,6 +986,18 @@ static void sun8i_dwmac_exit(struct platform_device *pdev, void *priv)
 		regulator_disable(gmac->regulator);
 }
 
+static void sun8i_dwmac_set_mac_loopback(void __iomem *ioaddr, bool enable)
+{
+	u32 value = readl(ioaddr + EMAC_BASIC_CTL0);
+
+	if (enable)
+		value |= EMAC_LOOPBACK;
+	else
+		value &= ~EMAC_LOOPBACK;
+
+	writel(value, ioaddr + EMAC_BASIC_CTL0);
+}
+
 static const struct stmmac_ops sun8i_dwmac_ops = {
 	.core_init = sun8i_dwmac_core_init,
 	.set_mac = sun8i_dwmac_set_mac,
@@ -995,6 +1007,7 @@ static const struct stmmac_ops sun8i_dwmac_ops = {
 	.flow_ctrl = sun8i_dwmac_flow_ctrl,
 	.set_umac_addr = sun8i_dwmac_set_umac_addr,
 	.get_umac_addr = sun8i_dwmac_get_umac_addr,
+	.set_mac_loopback = sun8i_dwmac_set_mac_loopback,
 };
 
 static struct mac_device_info *sun8i_dwmac_setup(void *ppriv)