ata: ahci_brcmstb: disable NCQ for MIPS-based platforms

The most MIPS-based platforms need to disable NCQ while have the NCQ
capability in HOST_CAP, and several ARM-based platforms (eg. BCM7349A0,
BCM7445A0, BCM7445B0) need to disable too.

Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Brian Norris <computersforpeace@gmail.com>

drivers/ata/ahci_brcmstb.c

@@ -69,10 +69,15 @@
 	(DATA_ENDIAN << DMADESC_ENDIAN_SHIFT) |		\
 	(MMIO_ENDIAN << MMIO_ENDIAN_SHIFT))
 
+enum brcm_ahci_quirks {
+	BRCM_AHCI_QUIRK_NO_NCQ		= BIT(0),
+};
+
 struct brcm_ahci_priv {
 	struct device *dev;
 	void __iomem *top_ctrl;
 	u32 port_mask;
+	u32 quirks;
 };
 
 static const struct ata_port_info ahci_brcm_port_info = {
@@ -256,6 +261,9 @@ static int brcm_ahci_probe(struct platform_device *pdev)
 	if (IS_ERR(priv->top_ctrl))
 		return PTR_ERR(priv->top_ctrl);
 
+	if (of_device_is_compatible(dev->of_node, "brcm,bcm7425-ahci"))
+		priv->quirks |= BRCM_AHCI_QUIRK_NO_NCQ;
+
 	brcm_sata_init(priv);
 
 	priv->port_mask = brcm_ahci_get_portmask(pdev, priv);
@@ -273,6 +281,9 @@ static int brcm_ahci_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	if (priv->quirks & BRCM_AHCI_QUIRK_NO_NCQ)
+		hpriv->flags |= AHCI_HFLAG_NO_NCQ;
+
 	ret = ahci_platform_init_host(pdev, hpriv, &ahci_brcm_port_info,
 				      &ahci_platform_sht);
 	if (ret)