usb: xhci-mtk: check clock stability of U3_MAC

This is useful to find out the root cause when the Super Speed doesn't
work. Such as when the T-PHY is switched to PCIe or SATA, and affects
Super Speed function, the check will fail.

Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-mtk.c

@@ -43,6 +43,7 @@
 
 /* ip_pw_sts1 register */
 #define STS1_IP_SLEEP_STS	BIT(30)
+#define STS1_U3_MAC_RST	BIT(16)
 #define STS1_XHCI_RST		BIT(11)
 #define STS1_SYS125_RST	BIT(10)
 #define STS1_REF_RST		BIT(8)
@@ -125,6 +126,9 @@ static int xhci_mtk_host_enable(struct xhci_hcd_mtk *mtk)
 	check_val = STS1_SYSPLL_STABLE | STS1_REF_RST |
 			STS1_SYS125_RST | STS1_XHCI_RST;
 
+	if (mtk->num_u3_ports)
+		check_val |= STS1_U3_MAC_RST;
+
 	ret = readl_poll_timeout(&ippc->ip_pw_sts1, value,
 			  (check_val == (value & check_val)), 100, 20000);
 	if (ret) {