[PATCH v2 2/3] usb: chipidea: core: allow ci_irq_handler() handle both ID and VBUS change

[Xu Yang <xu.yang_2@nxp.com>]

For USB role switch-triggered IRQ, ID and VBUS change come together, for
example when switching from host to device mode. ID indicate a role switch
and VBUS is required to determine whether the device controller can start
operating. Currently, ci_irq_handler() handles only a single event per
invocation. This can cause an issue where switching to device mode results
in the device controller not working at all. Allowing ci_irq_handler() to
handle both ID and VBUS change in one call resolves this issue.

Meanwhile, this change also affects the VBUS event handling logic.
Previously, if an ID event indicated host mode the VBUS IRQ will be
ignored as the device disable BSE when stop() is called. With the new
behavior, if ID and VBUS IRQ occur together and the target mode is host,
the VBUS event is queued and ci_handle_vbus_change() will call
usb_gadget_vbus_connect(), after which USBMODE is switched to device mode,
causing host mode to stop working. To prevent this, an additional check is
added to skip handling VBUS event when current role is not device mode.

Suggested-by: Peter Chen <peter.chen@kernel.org>
Fixes: e1b5d2bed67c ("usb: chipidea: core: handle usb role switch in a common way")
Cc: stable@vger.kernel.org
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>

---
Changes in v2:
 - change ci_irq_handler() instead of assign id_event/b_sess_valid_event
   as true and queue otg work directly
---
 drivers/usb/chipidea/core.c | 45 +++++++++++++++++++------------------
 drivers/usb/chipidea/otg.c  |  3 +++
 2 files changed, 26 insertions(+), 22 deletions(-)

diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c
index 87be716dff3e..7cfabb04a4fb 100644
--- a/drivers/usb/chipidea/core.c
+++ b/drivers/usb/chipidea/core.c
@@ -544,30 +544,31 @@ static irqreturn_t ci_irq_handler(int irq, void *data)
 			if (ret == IRQ_HANDLED)
 				return ret;
 		}
-	}
 
-	/*
-	 * Handle id change interrupt, it indicates device/host function
-	 * switch.
-	 */
-	if (ci->is_otg && (otgsc & OTGSC_IDIE) && (otgsc & OTGSC_IDIS)) {
-		ci->id_event = true;
-		/* Clear ID change irq status */
-		hw_write_otgsc(ci, OTGSC_IDIS, OTGSC_IDIS);
-		ci_otg_queue_work(ci);
-		return IRQ_HANDLED;
-	}
+		/*
+		 * Handle id change interrupt, it indicates device/host function
+		 * switch.
+		 */
+		if ((otgsc & OTGSC_IDIE) && (otgsc & OTGSC_IDIS)) {
+			ci->id_event = true;
+			/* Clear ID change irq status */
+			hw_write_otgsc(ci, OTGSC_IDIS, OTGSC_IDIS);
+		}
 
-	/*
-	 * Handle vbus change interrupt, it indicates device connection
-	 * and disconnection events.
-	 */
-	if (ci->is_otg && (otgsc & OTGSC_BSVIE) && (otgsc & OTGSC_BSVIS)) {
-		ci->b_sess_valid_event = true;
-		/* Clear BSV irq */
-		hw_write_otgsc(ci, OTGSC_BSVIS, OTGSC_BSVIS);
-		ci_otg_queue_work(ci);
-		return IRQ_HANDLED;
+		/*
+		 * Handle vbus change interrupt, it indicates device connection
+		 * and disconnection events.
+		 */
+		if ((otgsc & OTGSC_BSVIE) && (otgsc & OTGSC_BSVIS)) {
+			ci->b_sess_valid_event = true;
+			/* Clear BSV irq */
+			hw_write_otgsc(ci, OTGSC_BSVIS, OTGSC_BSVIS);
+		}
+
+		if (ci->id_event || ci->b_sess_valid_event) {
+			ci_otg_queue_work(ci);
+			return IRQ_HANDLED;
+		}
 	}
 
 	/* Handle device/host interrupt */
diff --git a/drivers/usb/chipidea/otg.c b/drivers/usb/chipidea/otg.c
index 647e98f4e351..def933b73a90 100644
--- a/drivers/usb/chipidea/otg.c
+++ b/drivers/usb/chipidea/otg.c
@@ -130,6 +130,9 @@ enum ci_role ci_otg_role(struct ci_hdrc *ci)
 
 void ci_handle_vbus_change(struct ci_hdrc *ci)
 {
+	if (ci->role != CI_ROLE_GADGET)
+		return;
+
 	if (!ci->is_otg) {
 		if (ci->platdata->flags & CI_HDRC_FORCE_VBUS_ACTIVE_ALWAYS)
 			usb_gadget_vbus_connect(&ci->gadget);
-- 
2.34.1