xhci: refactor static MSI-X function

The current way the xhci driver sets up MSI/MSI-X interrupts is overly
complex and messy. The whole MSI/MSI-X setup can be done in one simple
function.

Start refactoring this by incorporating 'xhci_setup_msix()' into
'xhci_try_enable_msi()'. 'xhci_setup_msix()' is a static function which
is only called by 'xhci_try_enable_msi()'.
Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20231201150647.1307406-14-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-pci.c

@@ -145,31 +145,40 @@ static int xhci_setup_msi(struct xhci_hcd *xhci)
 	return ret;
 }
 
-/*
- * Set up MSI-X
- */
-static int xhci_setup_msix(struct xhci_hcd *xhci)
+static int xhci_try_enable_msi(struct usb_hcd *hcd)
 {
-	struct usb_hcd *hcd = xhci_to_hcd(xhci);
-	struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	struct pci_dev  *pdev;
 	int ret;
 
+	pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
 	/*
-	 * calculate number of msi-x vectors supported.
+	 * 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;
+
+	/* unregister the legacy interrupt */
+	if (hcd->irq)
+		free_irq(hcd->irq, hcd);
+	hcd->irq = 0;
+
+	/*
+	 * calculate number of MSI-X vectors supported.
 	 * - HCS_MAX_INTRS: the max number of interrupts the host can handle,
 	 *   with max number of interrupters based on the xhci HCSPARAMS1.
-	 * - num_online_cpus: maximum msi-x vectors per CPUs core.
+	 * - num_online_cpus: maximum MSI-X vectors per CPUs core.
 	 *   Add additional 1 vector to ensure always available interrupt.
 	 */
 	xhci->msix_count = min(num_online_cpus() + 1,
-				HCS_MAX_INTRS(xhci->hcs_params1));
+			       HCS_MAX_INTRS(xhci->hcs_params1));
 
 	ret = pci_alloc_irq_vectors(pdev, xhci->msix_count, xhci->msix_count,
-			PCI_IRQ_MSIX);
+				    PCI_IRQ_MSIX);
 	if (ret < 0) {
-		xhci_dbg_trace(xhci, trace_xhci_dbg_init,
-				"Failed to enable MSI-X");
-		return ret;
+		xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Failed to enable MSI-X");
+		goto setup_msi;
 	}
 
 	ret = request_irq(pci_irq_vector(pdev, 0), xhci_msi_irq, 0, "xhci_hcd",
@@ -177,37 +186,16 @@ static int xhci_setup_msix(struct xhci_hcd *xhci)
 	if (ret) {
 		xhci_dbg_trace(xhci, trace_xhci_dbg_init, "disable MSI-X interrupt");
 		pci_free_irq_vectors(pdev);
-		return ret;
+		goto setup_msi;
 	}
 
+	hcd->msi_enabled = 1;
 	hcd->msix_enabled = 1;
-	return ret;
-}
-
-static int xhci_try_enable_msi(struct usb_hcd *hcd)
-{
-	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
-	struct pci_dev  *pdev;
-	int ret;
-
-	pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
-	/*
-	 * 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;
-
-	/* unregister the legacy interrupt */
-	if (hcd->irq)
-		free_irq(hcd->irq, hcd);
-	hcd->irq = 0;
-
-	ret = xhci_setup_msix(xhci);
-	if (ret)
-		/* fall back to msi*/
-		ret = xhci_setup_msi(xhci);
+	return 0;
 
+setup_msi:
+	/* fall back to MSI */
+	ret = xhci_setup_msi(xhci);
 	if (!ret) {
 		hcd->msi_enabled = 1;
 		return 0;