Hello.
The dwc3 driver in gadget mode has the ability to send
a remote wakeup signal to the host by writing 1 to the srp file:
echo 1 > /sys/class/udc/XXX/srp
I am trying to implement the same feature for dwc2, but I ran
into a problem. My naive and clumsy implementation is able
to wake up the host, but after that dwc2 stops processing
any interrupts and the gadget stops working.
At the same time, if I send the host to suspend, and then
it is awakened independently (for example, using the hardware
keyboard), then I see that dwc2 handles interrupts
and starts working again. I used the protocol analyzer
and made sure that the gadget with dwc2 is really correctly
suspended and wakes up.
I suppose remote wakeup signaling causes the controller
to switch to some incomprehensible (for me) state, and I need
to do something so that everything works again and dwc2
can receive a wake-up event from the host after signaling.
I don't have any DesignWare documentation, so I hope someone
can help me. Thanks.
diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index c581ee41a..14dfb678a 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -4660,6 +4660,21 @@ static int dwc2_hsotg_vbus_draw(struct usb_gadget *gadget, unsigned int mA)
return usb_phy_set_power(hsotg->uphy, mA);
}
+static int dwc2_hsotg_wakeup(struct usb_gadget *gadget)
+{
+ struct dwc2_hsotg *hsotg = to_hsotg(gadget);
+ unsigned long flags;
+
+ spin_lock_irqsave(&hsotg->lock, flags);
+
+ dwc2_set_bit(hsotg, DCTL, DCTL_RMTWKUPSIG);
+ mdelay(10);
+ dwc2_clear_bit(hsotg, DCTL, DCTL_RMTWKUPSIG);
+
+ spin_unlock_irqrestore(&hsotg->lock, flags);
+ return 0;
+}
+
static const struct usb_gadget_ops dwc2_hsotg_gadget_ops = {
.get_frame = dwc2_hsotg_gadget_getframe,
.set_selfpowered = dwc2_hsotg_set_selfpowered,
@@ -4668,6 +4683,7 @@ static const struct usb_gadget_ops dwc2_hsotg_gadget_ops = {
.pullup = dwc2_hsotg_pullup,
.vbus_session = dwc2_hsotg_vbus_session,
.vbus_draw = dwc2_hsotg_vbus_draw,
+ .wakeup = dwc2_hsotg_wakeup,
};
/**
