xhci: Rework how we handle unresponsive or hoptlug removed hosts

Introduce a new xhci_hc_died() function that takes care of handling
pending commands and URBs if a host controller becomes unresponsive.

This addresses issues on hotpluggable xhci controllers that disappear
from the bus suddenly, often while the bus (PCI) remove function is
still being processed.

xhci_hc_died() sets a XHCI_STATUS_DYING flag to prevent new URBs and
commands or to be queued. The flag also ensures xhci_hc_died() will
give back pending commands and URBs once.

Host is considered dead if register read returns 0xffffffff, or host
fails to abort the command ring, or fails stopping an endpoint after
trying for 5 seconds.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 52153e1..3818504 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -2131,6 +2131,7 @@
 		char *buf, u16 wLength);
 int xhci_hub_status_data(struct usb_hcd *hcd, char *buf);
 int xhci_find_raw_port_number(struct usb_hcd *hcd, int port1);
+void xhci_hc_died(struct xhci_hcd *xhci);
 
 #ifdef CONFIG_PM
 int xhci_bus_suspend(struct usb_hcd *hcd);