ata: ahci_brcmstb: add a quirk for MIPS-based platforms

Whereas ARM-based platforms have four phy interface registers and
information, the MIPS-based platforms have only three registers, and
there are no information and documentation. In the original BSP, It
using "strict-ahci" did not control these registers.

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

@@ -71,6 +71,7 @@
 
 enum brcm_ahci_quirks {
 	BRCM_AHCI_QUIRK_NO_NCQ		= BIT(0),
+	BRCM_AHCI_QUIRK_SKIP_PHY_ENABLE	= BIT(1),
 };
 
 struct brcm_ahci_priv {
@@ -119,6 +120,9 @@ static void brcm_sata_phy_enable(struct brcm_ahci_priv *priv, int port)
 	void __iomem *p;
 	u32 reg;
 
+	if (priv->quirks & BRCM_AHCI_QUIRK_SKIP_PHY_ENABLE)
+		return;
+
 	/* clear PHY_DEFAULT_POWER_STATE */
 	p = phyctrl + SATA_TOP_CTRL_PHY_CTRL_1;
 	reg = brcm_sata_readreg(p);
@@ -148,6 +152,9 @@ static void brcm_sata_phy_disable(struct brcm_ahci_priv *priv, int port)
 	void __iomem *p;
 	u32 reg;
 
+	if (priv->quirks & BRCM_AHCI_QUIRK_SKIP_PHY_ENABLE)
+		return;
+
 	/* power-off the PHY digital logic */
 	p = phyctrl + SATA_TOP_CTRL_PHY_CTRL_2;
 	reg = brcm_sata_readreg(p);
@@ -261,8 +268,10 @@ 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"))
+	if (of_device_is_compatible(dev->of_node, "brcm,bcm7425-ahci")) {
 		priv->quirks |= BRCM_AHCI_QUIRK_NO_NCQ;
+		priv->quirks |= BRCM_AHCI_QUIRK_SKIP_PHY_ENABLE;
+	}
 
 	brcm_sata_init(priv);