In DWC3 versions < 2.50a configured without
Hibernation mode enabled, there will be an
extra link status change interrupt if device
detects host-initiated U3 exit.
In that case, core will generate an unnecessary
U3 -> RESUME transition which should be ignored
by the driver.
Signed-off-by: Felipe Balbi <balbi@xxxxxx>
---
drivers/usb/dwc3/gadget.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index a04342f..39d8e5a 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2280,6 +2280,34 @@ static void dwc3_gadget_linksts_change_interrupt(struct dwc3 *dwc,
unsigned int evtinfo)
{
enum dwc3_link_state next = evtinfo & DWC3_LINK_STATE_MASK;
+ unsigned int pwropt;
+
+ /*
+ * WORKAROUND: DWC3 < 2.50a have an issue when configured without
+ * Hibernation mode enabled which would show up when device detects
+ * host-initiated U3 exit.
+ *
+ * In that case, device will generate a Link State Change Interrupt
+ * from U3 to RESUME which is only necessary if Hibernation is
+ * configured in.
+ *
+ * There are no functional changes due to such spurious event and we
+ * just need to ignore it.
+ *
+ * Refers to:
+ *
+ * STAR#9000570034 RTL: SS Resume event generated in non-Hibernation
+ * operational mode
+ */
+ pwropt = DWC3_GHWPARAMS1_EN_PWROPT(dwc->hwparams.hwparams1);
+ if ((dwc->revision < DWC3_REVISION_250A) &&
+ (pwropt != DWC3_GHWPARAMS1_EN_PWROPT_HIB)) {
+ if ((dwc->link_state == DWC3_LINK_STATE_U3) &&
+ (next == DWC3_LINK_STATE_RESUME)) {
+ dev_vdbg(dwc->dev, "ignoring transition U3 -> Resume\n");
+ return;
+ }
+ }
/*
* WORKAROUND: DWC3 Revisions <1.83a have an issue which, depending
--
1.8.1.rc1.5.g7e0651a
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