usb: dwc3: fix gadget mode suspend interrupt handler issue

When work in gadget mode, currently driver doesn't update software level
link_state correctly as link state change event is not enabled for most
devices, in function dwc3_gadget_suspend_interrupt(), it will only pass
suspend event to UDC core when software level link state changes, so when
interrupt generated in sequences of suspend -> reset -> conndone ->
suspend, link state is not updated during reset and conndone, so second
suspend interrupt event will not pass to UDC core.

Remove link_state compare in dwc3_gadget_suspend_interrupt() and add a
suspended flag to replace the compare function.

Fixes: 799e9dc ("usb: dwc3: gadget: conditionally disable Link State change events")
Cc: stable <stable@kernel.org>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
Link: https://lore.kernel.org/r/20230512004524.31950-1-quic_linyyuan@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Linyu Yuan

drivers/usb/dwc3/core.h

@@ -1116,6 +1116,7 @@ struct dwc3_scratchpad_array {
  * @dis_metastability_quirk: set to disable metastability quirk.
  * @dis_split_quirk: set to disable split boundary.
  * @wakeup_configured: set if the device is configured for remote wakeup.
+ * @suspended: set to track suspend event due to U3/L2.
  * @imod_interval: set the interrupt moderation interval in 250ns
  *			increments or 0 to disable.
  * @max_cfg_eps: current max number of IN eps used across all USB configs.
@@ -1332,6 +1333,7 @@ struct dwc3 {
 	unsigned		dis_split_quirk:1;
 	unsigned		async_callbacks:1;
 	unsigned		wakeup_configured:1;
+	unsigned		suspended:1;
 
 	u16			imod_interval;
 

drivers/usb/dwc3/gadget.c

@@ -2440,6 +2440,7 @@ static int dwc3_gadget_func_wakeup(struct usb_gadget *g, int intf_id)
 			return -EINVAL;
 		}
 		dwc3_resume_gadget(dwc);
+		dwc->suspended = false;
 		dwc->link_state = DWC3_LINK_STATE_U0;
 	}
 
@@ -3942,6 +3943,8 @@ static void dwc3_gadget_disconnect_interrupt(struct dwc3 *dwc)
 {
 	int			reg;
 
+	dwc->suspended = false;
+
 	dwc3_gadget_set_link_state(dwc, DWC3_LINK_STATE_RX_DET);
 
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
@@ -3966,6 +3969,8 @@ static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc)
 {
 	u32			reg;
 
+	dwc->suspended = false;
+
 	/*
 	 * Ideally, dwc3_reset_gadget() would trigger the function
 	 * drivers to stop any active transfers through ep disable.
@@ -4184,6 +4189,8 @@ static void dwc3_gadget_conndone_interrupt(struct dwc3 *dwc)
 
 static void dwc3_gadget_wakeup_interrupt(struct dwc3 *dwc, unsigned int evtinfo)
 {
+	dwc->suspended = false;
+
 	/*
 	 * TODO take core out of low power mode when that's
 	 * implemented.
@@ -4281,6 +4288,7 @@ static void dwc3_gadget_linksts_change_interrupt(struct dwc3 *dwc,
 		if (dwc->gadget->wakeup_armed) {
 			dwc3_gadget_enable_linksts_evts(dwc, false);
 			dwc3_resume_gadget(dwc);
+			dwc->suspended = false;
 		}
 		break;
 	case DWC3_LINK_STATE_U1:
@@ -4307,8 +4315,10 @@ static void dwc3_gadget_suspend_interrupt(struct dwc3 *dwc,
 {
 	enum dwc3_link_state next = evtinfo & DWC3_LINK_STATE_MASK;
 
-	if (dwc->link_state != next && next == DWC3_LINK_STATE_U3)
+	if (!dwc->suspended && next == DWC3_LINK_STATE_U3) {
+		dwc->suspended = true;
 		dwc3_suspend_gadget(dwc);
+	}
 
 	dwc->link_state = next;
 }