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Commit 6a29beef authored by Peter Chen's avatar Peter Chen Committed by Greg Kroah-Hartman
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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: default avatarPeter Chen <peter.chen@nxp.com>
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7480d912

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