usb: dwc2: exit hibernation on session request

Controller enters hibernation through suspend interrupt on
disconnection. On connection, session request interrupt is generated.
dwc2 must exit hibernation and restore state from this interrupt
before continuing.

In host mode, exit from hibernation is handled by bus_resume function.
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
Signed-off-by: Gregory Herrero <gregory.herrero@intel.com>
Tested-by: Robert Baldyga <r.baldyga@samsung.com>
Tested-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Tested-by: John Youn <johnyoun@synopsys.com>
Acked-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc2/core_intr.c

@@ -313,16 +313,28 @@ static void dwc2_handle_conn_id_status_change_intr(struct dwc2_hsotg *hsotg)
  */
 static void dwc2_handle_session_req_intr(struct dwc2_hsotg *hsotg)
 {
-	dev_dbg(hsotg->dev, "++Session Request Interrupt++\n");
+	int ret;
+
+	dev_dbg(hsotg->dev, "Session request interrupt - lx_state=%d\n",
+							hsotg->lx_state);
 
 	/* Clear interrupt */
 	dwc2_writel(GINTSTS_SESSREQINT, hsotg->regs + GINTSTS);
 
-	/*
-	 * Report disconnect if there is any previous session established
-	 */
-	if (dwc2_is_device_mode(hsotg))
+	if (dwc2_is_device_mode(hsotg)) {
+		if (hsotg->lx_state == DWC2_L2) {
+			ret = dwc2_exit_hibernation(hsotg, true);
+			if (ret && (ret != -ENOTSUPP))
+				dev_err(hsotg->dev,
+					"exit hibernation failed\n");
+		}
+
+		/*
+		 * Report disconnect if there is any previous session
+		 * established
+		 */
 		dwc2_hsotg_disconnect(hsotg);
+	}
 }
 
 /*