xhci: factor out parts of xhci_gen_setup()

Factoring out parts of xhci_gen_setup() has two motivations:
- When adding functionaliy to omit shared hcd if not needed in a
  subsequent patch, we'll have to call xhci_hcd_init_usb3_data()
  from two places.
- It reduces size of xhci_gen_setup() and makes it better readable.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220511220450.85367-2-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci.c

@@ -5209,34 +5209,9 @@ static int xhci_get_frame(struct usb_hcd *hcd)
 	return readl(&xhci->run_regs->microframe_index) >> 3;
 }
 
-int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
+static void xhci_hcd_init_usb2_data(struct xhci_hcd *xhci, struct usb_hcd *hcd)
 {
-	struct xhci_hcd		*xhci;
-	/*
-	 * TODO: Check with DWC3 clients for sysdev according to
-	 * quirks
-	 */
-	struct device		*dev = hcd->self.sysdev;
-	unsigned int		minor_rev;
-	int			retval;
-
-	/* Accept arbitrarily long scatter-gather lists */
-	hcd->self.sg_tablesize = ~0;
-
-	/* support to build packet from discontinuous buffers */
-	hcd->self.no_sg_constraint = 1;
-
-	/* XHCI controllers don't stop the ep queue on short packets :| */
-	hcd->self.no_stop_on_short = 1;
-
-	xhci = hcd_to_xhci(hcd);
-
-	if (usb_hcd_is_primary_hcd(hcd)) {
-		xhci->main_hcd = hcd;
 	xhci->usb2_rhub.hcd = hcd;
-		/* Mark the first roothub as being USB 2.0.
-		 * The xHCI driver will register the USB 3.0 roothub.
-		 */
 	hcd->speed = HCD_USB2;
 	hcd->self.root_hub->speed = USB_SPEED_HIGH;
 	/*
@@ -5245,7 +5220,12 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 	 * companion controller.
 	 */
 	hcd->has_tt = 1;
-	} else {
+}
+
+static void xhci_hcd_init_usb3_data(struct xhci_hcd *xhci, struct usb_hcd *hcd)
+{
+	unsigned int minor_rev;
+
 	/*
 	 * Early xHCI 1.1 spec did not mention USB 3.1 capable hosts
 	 * should return 0x31 for sbrn, or that the minor revision
@@ -5275,17 +5255,41 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 		break;
 	}
 	xhci_info(xhci, "Host supports USB 3.%x %sSuperSpeed\n",
-			  minor_rev,
-			  minor_rev ? "Enhanced " : "");
+		  minor_rev, minor_rev ? "Enhanced " : "");
 
 	xhci->usb3_rhub.hcd = hcd;
-		/* xHCI private pointer was set in xhci_pci_probe for the second
-		 * registered roothub.
+}
+
+int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
+{
+	struct xhci_hcd		*xhci;
+	/*
+	 * TODO: Check with DWC3 clients for sysdev according to
+	 * quirks
 	 */
+	struct device		*dev = hcd->self.sysdev;
+	int			retval;
+
+	/* Accept arbitrarily long scatter-gather lists */
+	hcd->self.sg_tablesize = ~0;
+
+	/* support to build packet from discontinuous buffers */
+	hcd->self.no_sg_constraint = 1;
+
+	/* XHCI controllers don't stop the ep queue on short packets :| */
+	hcd->self.no_stop_on_short = 1;
+
+	xhci = hcd_to_xhci(hcd);
+
+	if (usb_hcd_is_primary_hcd(hcd)) {
+		xhci_hcd_init_usb2_data(xhci, hcd);
+	} else {
+		xhci_hcd_init_usb3_data(xhci, hcd);
 		return 0;
 	}
 
 	mutex_init(&xhci->mutex);
+	xhci->main_hcd = hcd;
 	xhci->cap_regs = hcd->regs;
 	xhci->op_regs = hcd->regs +
 		HC_LENGTH(readl(&xhci->cap_regs->hc_capbase));