[PATCH 5.7 308/376] usb: musb: mediatek: add reset FADDR to zero in reset interrupt handle

[Greg Kroah-Hartman]

From: Macpaul Lin <macpaul.lin@xxxxxxxxxxxx>

commit 402bcac4b25b520c89ba60db85eb6316f36e797f upstream.

When receiving reset interrupt, FADDR need to be reset to zero in
peripheral mode. Otherwise ep0 cannot do enumeration when re-plugging USB
cable.

Signed-off-by: Macpaul Lin <macpaul.lin@xxxxxxxxxxxx>
Acked-by: Min Guo <min.guo@xxxxxxxxxxxx>
Signed-off-by: Bin Liu <b-liu@xxxxxx>
Link: https://lore.kernel.org/r/20200525025049.3400-5-b-liu@xxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/musb/mediatek.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/usb/musb/mediatek.c
+++ b/drivers/usb/musb/mediatek.c
@@ -208,6 +208,12 @@ static irqreturn_t generic_interrupt(int
 	musb->int_rx = musb_clearw(musb->mregs, MUSB_INTRRX);
 	musb->int_tx = musb_clearw(musb->mregs, MUSB_INTRTX);
 
+	if ((musb->int_usb & MUSB_INTR_RESET) && !is_host_active(musb)) {
+		/* ep0 FADDR must be 0 when (re)entering peripheral mode */
+		musb_ep_select(musb->mregs, 0);
+		musb_writeb(musb->mregs, MUSB_FADDR, 0);
+	}
+
 	if (musb->int_usb || musb->int_tx || musb->int_rx)
 		retval = musb_interrupt(musb);