usb: dwc3: workaround: missing disconnect event
DWC3 revisions <1.88a have an issue which would
case a missing Disconnect event if cable is
disconnected while there's a Setup packet
pending the FIFO.
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 6704a52..7c98b3f 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1640,6 +1640,7 @@
dwc->start_config_issued = false;
dwc->gadget.speed = USB_SPEED_UNKNOWN;
+ dwc->setup_packet_pending = false;
}
static void dwc3_gadget_usb3_phy_power(struct dwc3 *dwc, int on)
@@ -1676,6 +1677,37 @@
dev_vdbg(dwc->dev, "%s\n", __func__);
+ /*
+ * WORKAROUND: DWC3 revisions <1.88a have an issue which
+ * would cause a missing Disconnect Event if there's a
+ * pending Setup Packet in the FIFO.
+ *
+ * There's no suggested workaround on the official Bug
+ * report, which states that "unless the driver/application
+ * is doing any special handling of a disconnect event,
+ * there is no functional issue".
+ *
+ * Unfortunately, it turns out that we _do_ some special
+ * handling of a disconnect event, namely complete all
+ * pending transfers, notify gadget driver of the
+ * disconnection, and so on.
+ *
+ * Our suggested workaround is to follow the Disconnect
+ * Event steps here, instead, based on a setup_packet_pending
+ * flag. Such flag gets set whenever we have a XferNotReady
+ * event on EP0 and gets cleared on XferComplete for the
+ * same endpoint.
+ *
+ * Refers to:
+ *
+ * STAR#9000466709: RTL: Device : Disconnect event not
+ * generated if setup packet pending in FIFO
+ */
+ if (dwc->revision < DWC3_REVISION_188A) {
+ if (dwc->setup_packet_pending)
+ dwc3_gadget_disconnect_interrupt(dwc);
+ }
+
/* Enable PHYs */
dwc3_gadget_usb2_phy_power(dwc, true);
dwc3_gadget_usb3_phy_power(dwc, true);