From: Peter Chen Date: Wed, 17 May 2017 15:32:02 +0000 (+0300) Subject: usb: host: xhci-ring: don't need to clear interrupt pending for MSI enabled hcd X-Git-Tag: MMI-PSA29.97-13-9~5558^2~7 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6a29beef9d1b16c762e469d77e28c3de3f5c3dbb;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git usb: host: xhci-ring: don't need to clear interrupt pending for MSI enabled hcd According to xHCI spec Figure 30: Interrupt Throttle Flow Diagram If PCI Message Signaled Interrupts (MSI or MSI-X) are enabled, then the assertion of the Interrupt Pending (IP) flag in Figure 30 generates a PCI Dword write. The IP flag is automatically cleared by the completion of the PCI write. the MSI enabled HCs don't need to clear interrupt pending bit, but hcd->irq = 0 doesn't equal to MSI enabled HCD. At some Dual-role controller software designs, it sets hcd->irq as 0 to avoid HCD requesting interrupt, and they want to decide when to call usb_hcd_irq by software. Signed-off-by: Peter Chen Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 507ba7734b94..0830b25f9499 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -2707,12 +2707,9 @@ irqreturn_t xhci_irq(struct usb_hcd *hcd) */ status |= STS_EINT; writel(status, &xhci->op_regs->status); - /* FIXME when MSI-X is supported and there are multiple vectors */ - /* Clear the MSI-X event interrupt status */ - if (hcd->irq) { + if (!hcd->msi_enabled) { u32 irq_pending; - /* Acknowledge the PCI interrupt */ irq_pending = readl(&xhci->ir_set->irq_pending); irq_pending |= IMAN_IP; writel(irq_pending, &xhci->ir_set->irq_pending); diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 2d1310220832..71eb2991c698 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -359,9 +359,10 @@ static int xhci_try_enable_msi(struct usb_hcd *hcd) /* fall back to msi*/ ret = xhci_setup_msi(xhci); - if (!ret) - /* hcd->irq is 0, we have MSI */ + if (!ret) { + hcd->msi_enabled = 1; return 0; + } if (!pdev->irq) { xhci_err(xhci, "No msi-x/msi found and no IRQ in BIOS\n"); diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h index a469999a106d..50398b69ca44 100644 --- a/include/linux/usb/hcd.h +++ b/include/linux/usb/hcd.h @@ -148,6 +148,7 @@ struct usb_hcd { unsigned rh_registered:1;/* is root hub registered? */ unsigned rh_pollable:1; /* may we poll the root hub? */ unsigned msix_enabled:1; /* driver has MSI-X enabled? */ + unsigned msi_enabled:1; /* driver has MSI enabled? */ unsigned remove_phy:1; /* auto-remove USB phy */ /* The next flag is a stopgap, to be removed when all the HCDs