usb: host: xhci-ring: don't need to clear interrupt pending for MSI enabled hcd (6a29beef) · Commits · 戴 / test

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 <peter.chen@nxp.com> Signed-off-by:

Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/xhci-ring.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -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);

drivers/usb/host/xhci.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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");

include/linux/usb/hcd.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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

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