usb: xhci: wait for CNR controller not ready bit in xhci resume

BugLink: https://bugs.launchpad.net/bugs/1848780

commit a70bcbc3 upstream.

NVIDIA 3.1 xHCI card would lose power when moving power state into D3Cold.
Thus we need to wait for CNR bit to clear in xhci resume, just as in
xhci init.

[Minor changes to comment and commit message -Mathias]
Cc: <stable@vger.kernel.org>
Signed-off-by: Rick Tseng <rtseng@nvidia.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/1570190373-30684-6-git-send-email-mathias.nyman@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

drivers/usb/host/xhci.c

@@ -1044,6 +1044,18 @@ int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
 		hibernated = true;
 
 	if (!hibernated) {
+		/*
+		 * Some controllers might lose power during suspend, so wait
+		 * for controller not ready bit to clear, just as in xHC init.
+		 */
+		retval = xhci_handshake(&xhci->op_regs->status,
+					STS_CNR, 0, 10 * 1000 * 1000);
+		if (retval) {
+			xhci_warn(xhci, "Controller not ready at resume %d\n",
+				  retval);
+			spin_unlock_irq(&xhci->lock);
+			return retval;
+		}
 		/* step 1: restore register */
 		xhci_restore_registers(xhci);
 		/* step 2: initialize command ring buffer */