[PATCH v3 1/7] usb: dwc3: qcom: Keep wakeup IRQ enable/disable balanced on failed resume

[Faisal Hassan]

dwc3_qcom_resume() disables the wakeup interrupts before enabling the
clocks. If clk_bulk_prepare_enable() fails, it returns with them
disabled. The next suspend returns early on is_suspended without
re-enabling them, and the next resume disables them again, so every
failed resume leaves the disable depth one level deeper and host-mode
wakeup is lost for good.

Re-enabling them on the error path is not safe either: the
level-triggered ss_phy interrupt can stay asserted, and the handler
can't make progress while the controller is not resumed, so it would
fire continuously.

Track whether the wakeup interrupts are armed and make enabling and
disabling them idempotent. A failed resume now leaves them disarmed and
balanced, and the next suspend arms them again. Disarm them in resume
regardless of the wakeup setting, so interrupts armed by a runtime
suspend are also disarmed when system resume runs with device wakeup
disabled.

Signed-off-by: Faisal Hassan <faisal.hassan@xxxxxxxxxxxxxxxx>
---
 drivers/usb/dwc3/dwc3-qcom.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
index d44f093ac243..d4fda4dd81f6 100644
--- a/drivers/usb/dwc3/dwc3-qcom.c
+++ b/drivers/usb/dwc3/dwc3-qcom.c
@@ -81,6 +81,7 @@ struct dwc3_qcom {
 	enum usb_dr_mode	mode;
 	bool			is_suspended;
 	bool			pm_suspended;
+	bool			wakeup_irqs_armed;
 	struct icc_path		*icc_path_ddr;
 	struct icc_path		*icc_path_apps;
 
@@ -323,16 +324,26 @@ static void dwc3_qcom_disable_interrupts(struct dwc3_qcom *qcom)
 {
 	int i;
 
+	if (!qcom->wakeup_irqs_armed)
+		return;
+
 	for (i = 0; i < qcom->num_ports; i++)
 		dwc3_qcom_disable_port_interrupts(&qcom->ports[i]);
+
+	qcom->wakeup_irqs_armed = false;
 }
 
 static void dwc3_qcom_enable_interrupts(struct dwc3_qcom *qcom)
 {
 	int i;
 
+	if (qcom->wakeup_irqs_armed)
+		return;
+
 	for (i = 0; i < qcom->num_ports; i++)
 		dwc3_qcom_enable_port_interrupts(&qcom->ports[i]);
+
+	qcom->wakeup_irqs_armed = true;
 }
 
 static int dwc3_qcom_suspend(struct dwc3_qcom *qcom, bool wakeup)
@@ -377,8 +388,13 @@ static int dwc3_qcom_resume(struct dwc3_qcom *qcom, bool wakeup)
 	if (!qcom->is_suspended)
 		return 0;
 
-	if (dwc3_qcom_is_host(qcom) && wakeup)
-		dwc3_qcom_disable_interrupts(qcom);
+	/*
+	 * Wakeup interrupts may have been armed by an earlier runtime suspend
+	 * even if wakeup is now disabled, so always disarm them. On failure
+	 * they stay disarmed, as a level-triggered wakeup line could otherwise
+	 * keep firing while the controller can't be resumed.
+	 */
+	dwc3_qcom_disable_interrupts(qcom);
 
 	ret = clk_bulk_prepare_enable(qcom->num_clocks, qcom->clks);
 	if (ret < 0)
-- 
2.34.1