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

BugLink: https://bugs.launchpad.net/bugs/1850541
commit a70bcbc322837eda1ab5994d12db941dc9733a7d 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.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index e230425088ea7501c4e394b63d73f2cc09e1c7d5..a8c29de33409802df26da62d39f90ccf44a4853b 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/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 */