ahci: qoriq: added a condition to enable dma coherence

Enable DMA coherence in SATA controller on condition that
dma-coherent property exists in sata node in DTS.
Signed-off-by: NTang Yuantian <yuantian.tang@nxp.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

drivers/ata/ahci_qoriq.c

@@ -59,6 +59,7 @@ struct ahci_qoriq_priv {
 	struct ccsr_ahci *reg_base;
 	enum ahci_qoriq_type type;
 	void __iomem *ecc_addr;
+	bool is_dmacoherent;
 };
 
 static const struct of_device_id ahci_qoriq_of_match[] = {
@@ -164,26 +165,31 @@ static int ahci_qoriq_phy_init(struct ahci_host_priv *hpriv)
 		writel(LS1021A_PORT_PHY4, reg_base + PORT_PHY4);
 		writel(LS1021A_PORT_PHY5, reg_base + PORT_PHY5);
 		writel(AHCI_PORT_TRANS_CFG, reg_base + PORT_TRANS);
-		writel(AHCI_PORT_AXICC_CFG, reg_base + LS1021A_AXICC_ADDR);
+		if (qpriv->is_dmacoherent)
+			writel(AHCI_PORT_AXICC_CFG,
+					reg_base + LS1021A_AXICC_ADDR);
 		break;
 
 	case AHCI_LS1043A:
 		writel(AHCI_PORT_PHY_1_CFG, reg_base + PORT_PHY1);
 		writel(AHCI_PORT_TRANS_CFG, reg_base + PORT_TRANS);
-		writel(AHCI_PORT_AXICC_CFG, reg_base + PORT_AXICC);
+		if (qpriv->is_dmacoherent)
+			writel(AHCI_PORT_AXICC_CFG, reg_base + PORT_AXICC);
 		break;
 
 	case AHCI_LS2080A:
 		writel(AHCI_PORT_PHY_1_CFG, reg_base + PORT_PHY1);
 		writel(AHCI_PORT_TRANS_CFG, reg_base + PORT_TRANS);
-		writel(AHCI_PORT_AXICC_CFG, reg_base + PORT_AXICC);
+		if (qpriv->is_dmacoherent)
+			writel(AHCI_PORT_AXICC_CFG, reg_base + PORT_AXICC);
 		break;
 
 	case AHCI_LS1046A:
 		writel(LS1046A_SATA_ECC_DIS, qpriv->ecc_addr);
 		writel(AHCI_PORT_PHY_1_CFG, reg_base + PORT_PHY1);
 		writel(AHCI_PORT_TRANS_CFG, reg_base + PORT_TRANS);
-		writel(AHCI_PORT_AXICC_CFG, reg_base + PORT_AXICC);
+		if (qpriv->is_dmacoherent)
+			writel(AHCI_PORT_AXICC_CFG, reg_base + PORT_AXICC);
 		break;
 	}
 
@@ -221,6 +227,7 @@ static int ahci_qoriq_probe(struct platform_device *pdev)
 		if (IS_ERR(qoriq_priv->ecc_addr))
 			return PTR_ERR(qoriq_priv->ecc_addr);
 	}
+	qoriq_priv->is_dmacoherent = of_dma_is_coherent(np);
 
 	rc = ahci_platform_enable_resources(hpriv);
 	if (rc)