drivers: net: xgene: Implement the backward compatibility with the old and new firmware w.r.t Tx completion IRQ interrupt.

This patch implements the backward compatibility with the old firmware where
the Tx completion IRQ interrupt was absent whereas incase of new firmware
the Tx completion IRQ interrupt is present.

Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Signed-off-by: Suman Tripathi <stripathi@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/apm/xgene/xgene_enet_main.c

@@ -1024,11 +1024,13 @@ static int xgene_enet_get_resources(struct xgene_enet_pdata *pdata)
 	if (pdata->phy_mode != PHY_INTERFACE_MODE_RGMII) {
 		ret = platform_get_irq(pdev, 1);
 		if (ret <= 0) {
-			dev_err(dev, "Unable to get ENET Tx completion IRQ\n");
-			ret = ret ? : -ENXIO;
-			return ret;
+			pdata->cq_cnt = 0;
+			dev_info(dev, "Unable to get Tx completion IRQ,"
+				 "using Rx IRQ instead\n");
+		} else {
+			pdata->cq_cnt = XGENE_MAX_TXC_RINGS;
+			pdata->txc_irq = ret;
 		}
-		pdata->txc_irq = ret;
 	}
 
 	pdata->clk = devm_clk_get(&pdev->dev, NULL);
@@ -1105,13 +1107,11 @@ static void xgene_enet_setup_ops(struct xgene_enet_pdata *pdata)
 		pdata->mac_ops = &xgene_sgmac_ops;
 		pdata->port_ops = &xgene_sgport_ops;
 		pdata->rm = RM1;
-		pdata->cq_cnt = XGENE_MAX_TXC_RINGS;
 		break;
 	default:
 		pdata->mac_ops = &xgene_xgmac_ops;
 		pdata->port_ops = &xgene_xgport_ops;
 		pdata->rm = RM0;
-		pdata->cq_cnt = XGENE_MAX_TXC_RINGS;
 		break;
 	}