[PATCH v3] usb: ohci: add check for host controller functional states

[Yinbo Zhu]

The usb states of ohci controller include UsbOperational, UsbReset,
UsbSuspend and UsbResume. Among them, only the UsbOperational state
supports launching the start of frame for host controller according
the ohci protocol spec, but in S3/S4 press test procedure, it may
happen that the start of frame was launched in other usb states and
cause ohci works abnormally then kernel will allways report rcu
call trace. This patch was to add check for host controller
functional states and if it is not UsbOperational state that need
set INTR_SF in intrdisable register to ensure SOF Token generation
was been disabled.

Signed-off-by: Yinbo Zhu <zhuyinbo@xxxxxxxxxxx>
---
Change in v3:
		Rework the commit information.
		Move the patch code change to lower down position in ohci_irq.


 drivers/usb/host/ohci-hcd.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index 1f5e693..87aa9bb 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -879,7 +879,8 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
 {
 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
 	struct ohci_regs __iomem *regs = ohci->regs;
-	int			ints;
+	int			ints, ctl;
+
 
 	/* Read interrupt status (and flush pending writes).  We ignore the
 	 * optimization of checking the LSB of hcca->done_head; it doesn't
@@ -969,9 +970,15 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
 	 * when there's still unlinking to be done (next frame).
 	 */
 	ohci_work(ohci);
-	if ((ints & OHCI_INTR_SF) != 0 && !ohci->ed_rm_list
-			&& ohci->rh_state == OHCI_RH_RUNNING)
+
+	ctl = ohci_readl(ohci, &regs->control);
+
+	if (((ints & OHCI_INTR_SF) != 0 && !ohci->ed_rm_list
+			&& ohci->rh_state == OHCI_RH_RUNNING) ||
+			((ctl & OHCI_CTRL_HCFS) != OHCI_USB_OPER)) {
 		ohci_writel (ohci, OHCI_INTR_SF, &regs->intrdisable);
+		(void)ohci_readl(ohci, &regs->intrdisable);
+	}
 
 	if (ohci->rh_state == OHCI_RH_RUNNING) {
 		ohci_writel (ohci, ints, &regs->intrstatus);
-- 
1.8.3.1