USB: ohci-hcd.c: Add spinlock when disabling OHCI interrupts in ohci_…

…shutdown

This patch is used for fixing 'irq nobody care' issue during reboot

How to reproduce:
1)Prepare weston enabled environment
2)Connect USB mouse
3)Read input from the mouse and reboot
$ od -tx /dev/input/event0 &
$ reboot
4)Move the mouse while system shutdown
Don't need to move the mouse after "reboot: Restarting system"
5)Repeat step 3 and step 4 until below error occurs

Error log:
usb 2-1: USB disconnect, device number 2
irq 156: nobody cared (try booting with the "irqpoll" option)
Workqueue: usb_hub_wq hub_event
Call trace:
...
usbhid_disconnect+0x4c/0x78
usb_unbind_interface+0x6c/0x2a8
device_release_driver_internal+0x174/0x208
device_release_driver+0x14/0x20
bus_remove_device+0x114/0x128
device_del+0x1ac/0x300
usb_disable_device+0x8c/0x200
usb_disconnect+0xb4/0x218
...
handlers:
usb_hcd_irq
Disabling IRQ xen-troops#156

This issue occurs due to race condition between ohci_irq()
interrupt handler and ohci_shutdown()
Adding spin_lock_irq() to prevent interrupt raising while ohci is shutting
down can fix this issue.

When host controller dies, lock will be held by io_watchdog_func before
ohci_shutdown, so locking should be skipped in this case to prevent
deadlock

Signed-off-by: Tho Vu <tho.vu.wh@rvc.renesas.com>

drivers/usb/host/ohci-hcd.c

@@ -424,15 +424,24 @@ ohci_shutdown (struct usb_hcd *hcd)
 	struct ohci_hcd *ohci;
 
 	ohci = hcd_to_ohci (hcd);
-	ohci_writel(ohci, (u32) ~0, &ohci->regs->intrdisable);
 
+	/* Locking is not necessary if HC dies */
+	if (!test_bit(HCD_FLAG_DEAD, &hcd->flags))
+		spin_lock_irq(&ohci->lock);
+
+	/* Disable HC interrupts */
+	ohci_writel(ohci, (u32)~0, &ohci->regs->intrdisable);
 	/* Software reset, after which the controller goes into SUSPEND */
 	ohci_writel(ohci, OHCI_HCR, &ohci->regs->cmdstatus);
 	ohci_readl(ohci, &ohci->regs->cmdstatus);	/* flush the writes */
 	udelay(10);
 
 	ohci_writel(ohci, ohci->fminterval, &ohci->regs->fminterval);
 	ohci->rh_state = OHCI_RH_HALTED;
+
+	if (!test_bit(HCD_FLAG_DEAD, &hcd->flags))
+		spin_unlock_irq(&ohci->lock);
+
 }
 
 /*-------------------------------------------------------------------------*