usb/xhci: group MSI interrupt registration into its own function

This patch moves the complete MSI/MSI-X/Legacy dance into its own
function. There is however one difference: If the XHCI_BROKEN_MSI flag
is set then we don't free and register the irq, we simply return.
This is preparation for later PCI decouple.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 42 insertions, 28 deletions

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 7bf86774b1aa..583a3e330105 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -397,6 +397,45 @@ static int xhci_run_finished(struct xhci_hcd *xhci)
         return 0;
 }
 
+static int xhci_try_enable_msi(struct usb_hcd *hcd)
+{
+        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+        struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
+        int ret;
+
+        /*
+         * Some Fresco Logic host controllers advertise MSI, but fail to
+         * generate interrupts.  Don't even try to enable MSI.
+         */
+        if (xhci->quirks & XHCI_BROKEN_MSI)
+                return 0;
+
+        /* unregister the legacy interrupt */
+        if (hcd->irq)
+                free_irq(hcd->irq, hcd);
+        hcd->irq = -1;
+
+        ret = xhci_setup_msix(xhci);
+        if (ret)
+                /* fall back to msi*/
+                ret = xhci_setup_msi(xhci);
+
+        if (!ret)
+                /* hcd->irq is -1, we have MSI */
+                return 0;
+
+        /* fall back to legacy interrupt*/
+        ret = request_irq(pdev->irq, &usb_hcd_irq, IRQF_SHARED,
+                        hcd->irq_descr, hcd);
+        if (ret) {
+                xhci_err(xhci, "request interrupt %d failed\n",
+                                pdev->irq);
+                return ret;
+        }
+        hcd->irq = pdev->irq;
+        return 0;
+}
+
 /*
  * Start the HC after it was halted.
  *
@@ -413,9 +452,8 @@ int xhci_run(struct usb_hcd *hcd)
 {
         u32 temp;
         u64 temp_64;
-        u32 ret;
+        int ret;
         struct xhci_hcd *xhci = hcd_to_xhci(hcd);
-        struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
 
         /* Start the xHCI host controller running only after the USB 2.0 roothub
          * is setup.
@@ -426,34 +464,10 @@ int xhci_run(struct usb_hcd *hcd)
                 return xhci_run_finished(xhci);
 
         xhci_dbg(xhci, "xhci_run\n");
-        /* unregister the legacy interrupt */
-        if (hcd->irq)
-                free_irq(hcd->irq, hcd);
-        hcd->irq = -1;
 
-        /* Some Fresco Logic host controllers advertise MSI, but fail to
-         * generate interrupts.  Don't even try to enable MSI.
-         */
-        if (xhci->quirks & XHCI_BROKEN_MSI)
-                goto legacy_irq;
-
-        ret = xhci_setup_msix(xhci);
+        ret = xhci_try_enable_msi(hcd);
         if (ret)
-                /* fall back to msi*/
-                ret = xhci_setup_msi(xhci);
-
-        if (ret) {
-legacy_irq:
-                /* fall back to legacy interrupt*/
-                ret = request_irq(pdev->irq, &usb_hcd_irq, IRQF_SHARED,
-                                        hcd->irq_descr, hcd);
-                if (ret) {
-                        xhci_err(xhci, "request interrupt %d failed\n",
-                                        pdev->irq);
-                        return ret;
-                }
-                hcd->irq = pdev->irq;
-        }
+                return ret;
 
 #ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
         init_timer(&xhci->event_ring_timer);