usb: musb: break the huge isr musb_stage0_irq() into small functions

musb_stage0_irq() is 400+ lines long. Break its interrupt events
handling into each individual functions to make it easy to read.
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/musb_core.c

@@ -523,31 +523,8 @@ void musb_hnp_stop(struct musb *musb)
 
 static void musb_recover_from_babble(struct musb *musb);
 
-/*
- * Interrupt Service Routine to record USB "global" interrupts.
- * Since these do not happen often and signify things of
- * paramount importance, it seems OK to check them individually;
- * the order of the tests is specified in the manual
- *
- * @param musb instance pointer
- * @param int_usb register contents
- * @param devctl
- * @param power
- */
-
-static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
-				u8 devctl)
+static void musb_handle_intr_resume(struct musb *musb, u8 devctl)
 {
-	irqreturn_t handled = IRQ_NONE;
-
-	musb_dbg(musb, "<== DevCtl=%02x, int_usb=0x%x", devctl, int_usb);
-
-	/* in host mode, the peripheral may issue remote wakeup.
-	 * in peripheral mode, the host may resume the link.
-	 * spurious RESUME irqs happen too, paired with SUSPEND.
-	 */
-	if (int_usb & MUSB_INTR_RESUME) {
-		handled = IRQ_HANDLED;
 	musb_dbg(musb, "RESUME (%s)",
 			usb_otg_state_string(musb->xceiv->otg->state));
 
@@ -606,10 +583,11 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 				usb_otg_state_string(musb->xceiv->otg->state));
 		}
 	}
-	}
+}
 
-	/* see manual for the order of the tests */
-	if (int_usb & MUSB_INTR_SESSREQ) {
+/* return IRQ_HANDLED to tell the caller to return immediately */
+static irqreturn_t musb_handle_intr_sessreq(struct musb *musb, u8 devctl)
+{
 	void __iomem *mbase = musb->mregs;
 
 	if ((devctl & MUSB_DEVCTL_VBUS) == MUSB_DEVCTL_VBUS
@@ -634,10 +612,11 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 	MUSB_HST_MODE(musb);
 	musb_platform_set_vbus(musb, 1);
 
-		handled = IRQ_HANDLED;
-	}
+	return IRQ_NONE;
+}
 
-	if (int_usb & MUSB_INTR_VBUSERROR) {
+static void musb_handle_intr_vbuserr(struct musb *musb, u8 devctl)
+{
 	int	ignore = 0;
 
 	/* During connection as an A-Device, we may see a short
@@ -705,13 +684,12 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 	/* go through A_WAIT_VFALL then start a new session */
 	if (!ignore)
 		musb_platform_set_vbus(musb, 0);
-		handled = IRQ_HANDLED;
-	}
+}
 
-	if (int_usb & MUSB_INTR_SUSPEND) {
+static void musb_handle_intr_suspend(struct musb *musb, u8 devctl)
+{
 	musb_dbg(musb, "SUSPEND (%s) devctl %02x",
 		usb_otg_state_string(musb->xceiv->otg->state), devctl);
-		handled = IRQ_HANDLED;
 
 	switch (musb->xceiv->otg->state) {
 	case OTG_STATE_A_PERIPHERAL:
@@ -763,14 +741,13 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 		musb->is_active = 0;
 		break;
 	}
-	}
+}
 
-	if (int_usb & MUSB_INTR_CONNECT) {
+static void musb_handle_intr_connect(struct musb *musb, u8 devctl, u8 int_usb)
+{
 	struct usb_hcd *hcd = musb->hcd;
 
-		handled = IRQ_HANDLED;
 	musb->is_active = 1;
-
 	musb->ep0_stage = MUSB_EP0_START;
 
 	musb->intrtxe = musb->epmask;
@@ -821,13 +798,13 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 
 	musb_dbg(musb, "CONNECT (%s) devctl %02x",
 			usb_otg_state_string(musb->xceiv->otg->state), devctl);
-	}
+}
 
-	if (int_usb & MUSB_INTR_DISCONNECT) {
+static void musb_handle_intr_disconnect(struct musb *musb, u8 devctl)
+{
 	musb_dbg(musb, "DISCONNECT (%s) as %s, devctl %02x",
 			usb_otg_state_string(musb->xceiv->otg->state),
 			MUSB_MODE(musb), devctl);
-		handled = IRQ_HANDLED;
 
 	switch (musb->xceiv->otg->state) {
 	case OTG_STATE_A_HOST:
@@ -866,13 +843,14 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 			usb_otg_state_string(musb->xceiv->otg->state));
 		break;
 	}
-	}
+}
 
-	/* mentor saves a bit: bus reset and babble share the same irq.
+/*
+ * mentor saves a bit: bus reset and babble share the same irq.
  * only host sees babble; only peripheral sees bus reset.
  */
-	if (int_usb & MUSB_INTR_RESET) {
-		handled = IRQ_HANDLED;
+static void musb_handle_intr_reset(struct musb *musb)
+{
 	if (is_host_active(musb)) {
 		/*
 		 * When BABBLE happens what we can depends on which
@@ -920,6 +898,66 @@ static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
 				usb_otg_state_string(musb->xceiv->otg->state));
 		}
 	}
+}
+
+/*
+ * Interrupt Service Routine to record USB "global" interrupts.
+ * Since these do not happen often and signify things of
+ * paramount importance, it seems OK to check them individually;
+ * the order of the tests is specified in the manual
+ *
+ * @param musb instance pointer
+ * @param int_usb register contents
+ * @param devctl
+ * @param power
+ */
+
+static irqreturn_t musb_stage0_irq(struct musb *musb, u8 int_usb,
+				u8 devctl)
+{
+	irqreturn_t handled = IRQ_NONE;
+
+	musb_dbg(musb, "<== DevCtl=%02x, int_usb=0x%x", devctl, int_usb);
+
+	/* in host mode, the peripheral may issue remote wakeup.
+	 * in peripheral mode, the host may resume the link.
+	 * spurious RESUME irqs happen too, paired with SUSPEND.
+	 */
+	if (int_usb & MUSB_INTR_RESUME) {
+		musb_handle_intr_resume(musb, devctl);
+		handled = IRQ_HANDLED;
+	}
+
+	/* see manual for the order of the tests */
+	if (int_usb & MUSB_INTR_SESSREQ) {
+		if (musb_handle_intr_sessreq(musb, devctl))
+			return IRQ_HANDLED;
+		handled = IRQ_HANDLED;
+	}
+
+	if (int_usb & MUSB_INTR_VBUSERROR) {
+		musb_handle_intr_vbuserr(musb, devctl);
+		handled = IRQ_HANDLED;
+	}
+
+	if (int_usb & MUSB_INTR_SUSPEND) {
+		musb_handle_intr_suspend(musb, devctl);
+		handled = IRQ_HANDLED;
+	}
+
+	if (int_usb & MUSB_INTR_CONNECT) {
+		musb_handle_intr_connect(musb, devctl, int_usb);
+		handled = IRQ_HANDLED;
+	}
+
+	if (int_usb & MUSB_INTR_DISCONNECT) {
+		musb_handle_intr_disconnect(musb, devctl);
+		handled = IRQ_HANDLED;
+	}
+
+	if (int_usb & MUSB_INTR_RESET) {
+		musb_handle_intr_reset(musb);
+		handled = IRQ_HANDLED;
 	}
 
 #if 0