FEX-Emu/linux
1
0
Fork 0
mirror of https://github.com/FEX-Emu/linux.git synced 2024-12-23 01:40:30 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

usb: host: xhci-ring: don't need to clear interrupt pending for MSI enabled hcd

Browse Source 
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>
This commit is contained in:
Peter Chen 2017-05-17 18:32:02 +03:00 committed by Greg Kroah-Hartman
parent 7480d912d5
commit 6a29beef9d
3 changed files with 5 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/usb/host/xhci-ring.c
View File

@ -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);

5
drivers/usb/host/xhci.c
View File

@ -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");

1
include/linux/usb/hcd.h
View File

@ -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