from: https://patchwork.kernel.org/project/linux-mediatek/patch/20221118110116.20165-1-chunfeng.yun@mediatek.com/

diff --git a/drivers/usb/host/xhci-mtk.c b/drivers/usb/host/xhci-mtk.c
index 01705e559c42..cff3c4aea036 100644
--- a/drivers/usb/host/xhci-mtk.c
+++ b/drivers/usb/host/xhci-mtk.c
@@ -485,6 +485,7 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 	const struct hc_driver *driver;
 	struct xhci_hcd *xhci;
 	struct resource *res;
+	struct usb_hcd *usb3_hcd;
 	struct usb_hcd *hcd;
 	int ret = -ENODEV;
 	int wakeup_irq;
@@ -593,6 +594,7 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 
 	xhci = hcd_to_xhci(hcd);
 	xhci->main_hcd = hcd;
+	xhci->allow_single_roothub = 1;
 
 	/*
 	 * imod_interval is the interrupt moderation value in nanoseconds.
@@ -602,24 +604,29 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 	xhci->imod_interval = 5000;
 	device_property_read_u32(dev, "imod-interval-ns", &xhci->imod_interval);
 
-	xhci->shared_hcd = usb_create_shared_hcd(driver, dev,
-			dev_name(dev), hcd);
-	if (!xhci->shared_hcd) {
-		ret = -ENOMEM;
-		goto disable_device_wakeup;
-	}
-
 	ret = usb_add_hcd(hcd, irq, IRQF_SHARED);
 	if (ret)
-		goto put_usb3_hcd;
+		goto disable_device_wakeup;
 
-	if (HCC_MAX_PSA(xhci->hcc_params) >= 4 &&
+	if (!xhci_has_one_roothub(xhci)) {
+		xhci->shared_hcd = usb_create_shared_hcd(driver, dev,
+							 dev_name(dev), hcd);
+		if (!xhci->shared_hcd) {
+			ret = -ENOMEM;
+			goto dealloc_usb2_hcd;
+		}
+	}
+
+	usb3_hcd = xhci_get_usb3_hcd(xhci);
+	if (usb3_hcd && HCC_MAX_PSA(xhci->hcc_params) >= 4 &&
 	    !(xhci->quirks & XHCI_BROKEN_STREAMS))
-		xhci->shared_hcd->can_do_streams = 1;
+		usb3_hcd->can_do_streams = 1;
 
-	ret = usb_add_hcd(xhci->shared_hcd, irq, IRQF_SHARED);
-	if (ret)
-		goto dealloc_usb2_hcd;
+	if (xhci->shared_hcd) {
+		ret = usb_add_hcd(xhci->shared_hcd, irq, IRQF_SHARED);
+		if (ret)
+			goto put_usb3_hcd;
+	}
 
 	if (wakeup_irq > 0) {
 		ret = dev_pm_set_dedicated_wake_irq_reverse(dev, wakeup_irq);
@@ -641,13 +648,13 @@ static int xhci_mtk_probe(struct platform_device *pdev)
 	usb_remove_hcd(xhci->shared_hcd);
 	xhci->shared_hcd = NULL;
 
-dealloc_usb2_hcd:
-	usb_remove_hcd(hcd);
-
 put_usb3_hcd:
-	xhci_mtk_sch_exit(mtk);
 	usb_put_hcd(xhci->shared_hcd);
 
+dealloc_usb2_hcd:
+	xhci_mtk_sch_exit(mtk);
+	usb_remove_hcd(hcd);
+
 disable_device_wakeup:
 	device_init_wakeup(dev, false);
 
@@ -679,10 +686,15 @@ static int xhci_mtk_remove(struct platform_device *pdev)
 	dev_pm_clear_wake_irq(dev);
 	device_init_wakeup(dev, false);
 
-	usb_remove_hcd(shared_hcd);
-	xhci->shared_hcd = NULL;
+	if (shared_hcd) {
+		usb_remove_hcd(shared_hcd);
+		xhci->shared_hcd = NULL;
+	}
 	usb_remove_hcd(hcd);
-	usb_put_hcd(shared_hcd);
+
+	if (shared_hcd)
+		usb_put_hcd(shared_hcd);
+
 	usb_put_hcd(hcd);
 	xhci_mtk_sch_exit(mtk);
 	clk_bulk_disable_unprepare(BULK_CLKS_NUM, mtk->clks);
@@ -700,13 +712,16 @@ static int __maybe_unused xhci_mtk_suspend(struct device *dev)
 	struct xhci_hcd_mtk *mtk = dev_get_drvdata(dev);
 	struct usb_hcd *hcd = mtk->hcd;
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	struct usb_hcd *shared_hcd = xhci->shared_hcd;
 	int ret;
 
 	xhci_dbg(xhci, "%s: stop port polling\n", __func__);
 	clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
 	del_timer_sync(&hcd->rh_timer);
-	clear_bit(HCD_FLAG_POLL_RH, &xhci->shared_hcd->flags);
-	del_timer_sync(&xhci->shared_hcd->rh_timer);
+	if (shared_hcd) {
+		clear_bit(HCD_FLAG_POLL_RH, &shared_hcd->flags);
+		del_timer_sync(&shared_hcd->rh_timer);
+	}
 
 	ret = xhci_mtk_host_disable(mtk);
 	if (ret)
@@ -718,8 +733,10 @@ static int __maybe_unused xhci_mtk_suspend(struct device *dev)
 
 restart_poll_rh:
 	xhci_dbg(xhci, "%s: restart port polling\n", __func__);
-	set_bit(HCD_FLAG_POLL_RH, &xhci->shared_hcd->flags);
-	usb_hcd_poll_rh_status(xhci->shared_hcd);
+	if (shared_hcd) {
+		set_bit(HCD_FLAG_POLL_RH, &shared_hcd->flags);
+		usb_hcd_poll_rh_status(shared_hcd);
+	}
 	set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
 	usb_hcd_poll_rh_status(hcd);
 	return ret;
@@ -730,6 +747,7 @@ static int __maybe_unused xhci_mtk_resume(struct device *dev)
 	struct xhci_hcd_mtk *mtk = dev_get_drvdata(dev);
 	struct usb_hcd *hcd = mtk->hcd;
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	struct usb_hcd *shared_hcd = xhci->shared_hcd;
 	int ret;
 
 	usb_wakeup_set(mtk, false);
@@ -742,8 +760,10 @@ static int __maybe_unused xhci_mtk_resume(struct device *dev)
 		goto disable_clks;
 
 	xhci_dbg(xhci, "%s: restart port polling\n", __func__);
-	set_bit(HCD_FLAG_POLL_RH, &xhci->shared_hcd->flags);
-	usb_hcd_poll_rh_status(xhci->shared_hcd);
+	if (shared_hcd) {
+		set_bit(HCD_FLAG_POLL_RH, &shared_hcd->flags);
+		usb_hcd_poll_rh_status(shared_hcd);
+	}
 	set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
 	usb_hcd_poll_rh_status(hcd);
 	return 0;