xhci: rework 'xhci_try_enable_msi()' MSI and MSI-X setup code

Simplify 'xhci_try_enable_msi()' and reduce unnecessary function calls.

xHCI driver first tries to allocate 'num_online_cpu()' number of MSI-X
vectors, if that fails it falls back to a single MSI vector. There is no
good reason for this, we currently only support a primary interrupter.
However, we are still interested in knowing if there are more vectors
available, which will be utilized once we get secondary interrupter
support.

Call 'pci_alloc_irq_vectors()' once (with MSI-X and MSI flag), instead
of separately for MSI-X and MSI. And accept any number of MSI-X or MSI
vectors between 1 and 'num_online_cpu()'.

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/20231201150647.1307406-17-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 2307164a1e81640d0ad1f3efb5b92750fa0743e4..398f81b0500be02e02ce4d10342c690037a92459 100644 (file)
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -116,13 +116,13 @@ static void xhci_cleanup_msix(struct xhci_hcd *xhci)
        hcd->msix_enabled = 0;
 }
 
+/* Try enabling MSI-X with MSI and legacy IRQ as fallback */
 static int xhci_try_enable_msi(struct usb_hcd *hcd)
 {
+       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);
        /*
         * Some Fresco Logic host controllers advertise MSI, but fail to
         * generate interrupts.  Don't even try to enable MSI.
@@ -145,42 +145,28 @@ static int xhci_try_enable_msi(struct usb_hcd *hcd)
        xhci->nvecs = min(num_online_cpus() + 1,
                          HCS_MAX_INTRS(xhci->hcs_params1));
 
-       xhci->nvecs = pci_alloc_irq_vectors(pdev, xhci->nvecs, xhci->nvecs,
-                                           PCI_IRQ_MSIX);
+       /* TODO: Check with MSI Soc for sysdev */
+       xhci->nvecs = pci_alloc_irq_vectors(pdev, 1, xhci->nvecs,
+                                           PCI_IRQ_MSIX | PCI_IRQ_MSI);
        if (xhci->nvecs < 0) {
-               xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Failed to enable MSI-X");
-               goto setup_msi;
+               xhci_dbg_trace(xhci, trace_xhci_dbg_init,
+                              "failed to allocate IRQ vectors");
+               goto legacy_irq;
        }
 
        ret = request_irq(pci_irq_vector(pdev, 0), xhci_msi_irq, 0, "xhci_hcd",
                          xhci_to_hcd(xhci));
-       if (ret) {
-               xhci_dbg_trace(xhci, trace_xhci_dbg_init, "disable MSI-X interrupt");
-               pci_free_irq_vectors(pdev);
-               goto setup_msi;
-       }
+       if (ret)
+               goto free_irq_vectors;
 
        hcd->msi_enabled = 1;
-       hcd->msix_enabled = 1;
+       hcd->msix_enabled = pdev->msix_enabled;
        return 0;
 
-setup_msi:
-       /* TODO: Check with MSI Soc for sysdev */
-       xhci->nvecs = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
-       if (xhci->nvecs < 0) {
-               xhci_dbg_trace(xhci, trace_xhci_dbg_init, "failed to allocate MSI entry");
-               goto legacy_irq;
-       }
-
-       ret = request_irq(pdev->irq, xhci_msi_irq, 0, "xhci_hcd", xhci_to_hcd(xhci));
-       if (ret) {
-               xhci_dbg_trace(xhci, trace_xhci_dbg_init, "disable MSI interrupt");
-               pci_free_irq_vectors(pdev);
-               goto legacy_irq;
-       }
-
-       hcd->msi_enabled = 1;
-       return 0;
+free_irq_vectors:
+       xhci_dbg_trace(xhci, trace_xhci_dbg_init, "disable %s interrupt",
+                      pdev->msix_enabled ? "MSI-X" : "MSI");
+       pci_free_irq_vectors(pdev);
 
 legacy_irq:
        if (!pdev->irq) {