usb: dwc2: gadget: rework disconnect event handling

This patch adds a call to s3c_hsotg_disconnect() from 'end session'
interrupt (GOTGINT_SES_END_DET) to correctly notify gadget subsystem
about unplugged usb cable. DISCONNINT interrupt cannot be used for this
purpose, because it is asserted only in host mode.

To avoid reporting disconnect event more than once, a disconnect call has
been moved from USB_REQ_SET_ADDRESS handling function to SESSREQINT
interrupt. This way driver ensures that disconnect event is reported
either when usb cable is unplugged or every time the host starts a new
session. To handle devices which has been synthesized without
SRP support, connected state is set in ENUMDONE interrupt.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc2/core.h

@@ -687,6 +687,7 @@ struct dwc2_hsotg {
 	u8 ctrl_buff[8];
 
 	struct usb_gadget gadget;
+	unsigned int connected:1;
 	unsigned int setup;
 	unsigned long last_rst;
 	struct s3c_hsotg_ep *eps;
@@ -968,6 +969,7 @@ extern int s3c_hsotg_resume(struct dwc2_hsotg *dwc2);
 extern int dwc2_gadget_init(struct dwc2_hsotg *hsotg, int irq);
 extern void s3c_hsotg_core_init_disconnected(struct dwc2_hsotg *dwc2);
 extern void s3c_hsotg_core_connect(struct dwc2_hsotg *hsotg);
+extern void s3c_hsotg_disconnect(struct dwc2_hsotg *dwc2);
 #else
 static inline int s3c_hsotg_remove(struct dwc2_hsotg *dwc2)
 { return 0; }
@@ -979,6 +981,7 @@ static inline int dwc2_gadget_init(struct dwc2_hsotg *hsotg, int irq)
 { return 0; }
 static inline void s3c_hsotg_core_init_disconnected(struct dwc2_hsotg *dwc2) {}
 static inline void s3c_hsotg_core_connect(struct dwc2_hsotg *hsotg) {}
+static inline void s3c_hsotg_disconnect(struct dwc2_hsotg *dwc2) {}
 #endif
 
 #if IS_ENABLED(CONFIG_USB_DWC2_HOST) || IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)

drivers/usb/dwc2/core_intr.c

@@ -128,6 +128,9 @@ static void dwc2_handle_otg_intr(struct dwc2_hsotg *hsotg)
 			dwc2_op_state_str(hsotg));
 		gotgctl = readl(hsotg->regs + GOTGCTL);
 
+		if (dwc2_is_device_mode(hsotg))
+			s3c_hsotg_disconnect(hsotg);
+
 		if (hsotg->op_state == OTG_STATE_B_HOST) {
 			hsotg->op_state = OTG_STATE_B_PERIPHERAL;
 		} else {
@@ -314,6 +317,12 @@ static void dwc2_handle_session_req_intr(struct dwc2_hsotg *hsotg)
 
 	/* Clear interrupt */
 	writel(GINTSTS_SESSREQINT, hsotg->regs + GINTSTS);
+
+	/*
+	 * Report disconnect if there is any previous session established
+	 */
+	if (dwc2_is_device_mode(hsotg))
+		s3c_hsotg_disconnect(hsotg);
 }
 
 /*

drivers/usb/dwc2/gadget.c

@@ -1030,7 +1030,6 @@ static int s3c_hsotg_process_req_feature(struct dwc2_hsotg *hsotg,
 }
 
 static void s3c_hsotg_enqueue_setup(struct dwc2_hsotg *hsotg);
-static void s3c_hsotg_disconnect(struct dwc2_hsotg *hsotg);
 
 /**
  * s3c_hsotg_stall_ep0 - stall ep0
@@ -1108,7 +1107,6 @@ static void s3c_hsotg_process_control(struct dwc2_hsotg *hsotg,
 	if ((ctrl->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD) {
 		switch (ctrl->bRequest) {
 		case USB_REQ_SET_ADDRESS:
-			s3c_hsotg_disconnect(hsotg);
 			dcfg = readl(hsotg->regs + DCFG);
 			dcfg &= ~DCFG_DEVADDR_MASK;
 			dcfg |= (le16_to_cpu(ctrl->wValue) <<
@@ -2028,15 +2026,20 @@ static void kill_all_requests(struct dwc2_hsotg *hsotg,
  * transactions and signal the gadget driver that this
  * has happened.
  */
-static void s3c_hsotg_disconnect(struct dwc2_hsotg *hsotg)
+void s3c_hsotg_disconnect(struct dwc2_hsotg *hsotg)
 {
 	unsigned ep;
 
+	if (!hsotg->connected)
+		return;
+
+	hsotg->connected = 0;
 	for (ep = 0; ep < hsotg->num_of_eps; ep++)
 		kill_all_requests(hsotg, &hsotg->eps[ep], -ESHUTDOWN, true);
 
 	call_gadget(hsotg, disconnect);
 }
+EXPORT_SYMBOL_GPL(s3c_hsotg_disconnect);
 
 /**
  * s3c_hsotg_irq_fifoempty - TX FIFO empty interrupt handler
@@ -2289,6 +2292,7 @@ irq_retry:
 		writel(GINTSTS_ENUMDONE, hsotg->regs + GINTSTS);
 
 		s3c_hsotg_irq_enumdone(hsotg);
+		hsotg->connected = 1;
 	}
 
 	if (gintsts & (GINTSTS_OEPINT | GINTSTS_IEPINT)) {