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

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.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index aec69d2949738c0bc38e5af2a5c1baa12b6d4cf4..fe8f9ff580151f0f8cb960ef153c1f06b05e59ad 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -1108,6 +1108,18 @@ 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 */