usb: dwc2: Workaround case where GOTGCTL state is wrong

When removing a USB-A to USB-otg adapter cable, we get a change status
irq, and then in dwc2_conn_id_status_change, we erroneously see the
GOTGCTL_CONID_B flag set. This causes us to get stuck in the
"while (!dwc2_is_device_mode(hsotg))" loop, spitting out "Waiting for
Peripheral Mode, Mode=Host" warnings until it fails out many seconds
later.

This patch works around the issue by re-reading the GOTGCTL state to
check if the GOTGCTL_CONID_B is still set and if not restarting the
change status logic.

Cc: Wei Xu <xuwei5@hisilicon.com>
Cc: Guodong Xu <guodong.xu@linaro.org>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: John Youn <johnyoun@synopsys.com>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Chen Yu <chenyu56@huawei.com>
Cc: Vardan Mikayelyan <mvardan@synopsys.com>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Felipe Balbi <felipe.balbi@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Reviewed-by: Vardan Mikayelyan <mvardan@synopsys.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index 8b688b0416960386bf55de344ad785fb6764c1dc..e0d152f2c81bee2931957008ee9ec5f84771a2eb 100644 (file)
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -3237,6 +3237,14 @@ static void dwc2_conn_id_status_change(struct work_struct *work)
                                 dwc2_is_host_mode(hsotg) ? "Host" :
                                 "Peripheral");
                        msleep(20);
+                       /*
+                        * Sometimes the initial GOTGCTRL read is wrong, so
+                        * check it again and jump to host mode if that was
+                        * the case.
+                        */
+                       gotgctl = dwc2_readl(hsotg->regs + GOTGCTL);
+                       if (!(gotgctl & GOTGCTL_CONID_B))
+                               goto host;
                        if (++count > 250)
                                break;
                }
@@ -3251,6 +3259,7 @@ static void dwc2_conn_id_status_change(struct work_struct *work)
                spin_unlock_irqrestore(&hsotg->lock, flags);
                dwc2_hsotg_core_connect(hsotg);
        } else {
+host:
                /* A-Device connector (Host Mode) */
                dev_dbg(hsotg->dev, "connId A\n");
                while (!dwc2_is_host_mode(hsotg)) {