USB: xhci: Reduce reads and writes of interrupter registers.

[linux-flexiantxendom0.git] / drivers / usb / host / xhci-ring.c

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index f479f73..6860e9f 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2014,7 +2014,7 @@ static void xhci_handle_event(struct xhci_hcd *xhci)
 irqreturn_t xhci_irq(struct usb_hcd *hcd)
 {
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
-       u32 status, irq_pending;
+       u32 status;
        union xhci_trb *trb;
        u64 temp_64;
        union xhci_trb *event_ring_deq;
@@ -2024,17 +2024,15 @@ irqreturn_t xhci_irq(struct usb_hcd *hcd)
        trb = xhci->event_ring->dequeue;
        /* Check if the xHC generated the interrupt, or the irq is shared */
        status = xhci_readl(xhci, &xhci->op_regs->status);
-       irq_pending = xhci_readl(xhci, &xhci->ir_set->irq_pending);
-       if (status == 0xffffffff && irq_pending == 0xffffffff)
+       if (status == 0xffffffff)
                goto hw_died;
 
-       if (!(status & STS_EINT) && !ER_IRQ_PENDING(irq_pending)) {
+       if (!(status & STS_EINT)) {
                spin_unlock(&xhci->lock);
                xhci_warn(xhci, "Spurious interrupt.\n");
                return IRQ_NONE;
        }
        xhci_dbg(xhci, "op reg status = %08x\n", status);
-       xhci_dbg(xhci, "ir set irq_pending = %08x\n", irq_pending);
        xhci_dbg(xhci, "Event ring dequeue ptr:\n");
        xhci_dbg(xhci, "@%llx %08x %08x %08x %08x\n",
                        (unsigned long long)
@@ -2063,9 +2061,13 @@ hw_died:
        /* FIXME when MSI-X is supported and there are multiple vectors */
        /* Clear the MSI-X event interrupt status */
 
-       /* Acknowledge the interrupt */
-       irq_pending |= 0x3;
-       xhci_writel(xhci, irq_pending, &xhci->ir_set->irq_pending);
+       if (hcd->irq != -1) {
+               u32 irq_pending;
+               /* Acknowledge the PCI interrupt */
+               irq_pending = xhci_readl(xhci, &xhci->ir_set->irq_pending);
+               irq_pending |= 0x3;
+               xhci_writel(xhci, irq_pending, &xhci->ir_set->irq_pending);
+       }
 
        if (xhci->xhc_state & XHCI_STATE_DYING) {
                xhci_dbg(xhci, "xHCI dying, ignoring interrupt. "