From 23db9fd238d6ca5aa165900bf14fb42e3e2d0815 Mon Sep 17 00:00:00 2001 From: Apelete Seketeli Date: Thu, 19 Dec 2013 21:42:27 +0100 Subject: usb: musb: fix setting JZ4740 gadget periphal mode on reset JZ4740 USB Device Controller is not OTG compatible and does not have DEVCTL register in silicon. During ethernet-over-usb transactions, on reset, musb driver tries to read from DEVCTL and consequently sets device as host (A-Device) instead of peripheral (B-Device), which makes it a composite device to the USB gadget driver. This induces a kernel panic during power down where the USB gadget driver does a null pointer dereference when trying to access the composite device configuration. On reset, do not rely on DEVCTL value for setting gadget peripheral mode. Use is_otg flag instead to set it to B-Device. Signed-off-by: Apelete Seketeli Signed-off-by: Felipe Balbi --- drivers/usb/musb/musb_gadget.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'drivers/usb/musb/musb_gadget.c') diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c index c410a7ff150b..d4aa779339f1 100644 --- a/drivers/usb/musb/musb_gadget.c +++ b/drivers/usb/musb/musb_gadget.c @@ -2119,7 +2119,15 @@ __acquires(musb->lock) /* Normal reset, as B-Device; * or else after HNP, as A-Device */ - if (devctl & MUSB_DEVCTL_BDEVICE) { + if (!musb->g.is_otg) { + /* USB device controllers that are not OTG compatible + * may not have DEVCTL register in silicon. + * In that case, do not rely on devctl for setting + * peripheral mode. + */ + musb->xceiv->state = OTG_STATE_B_PERIPHERAL; + musb->g.is_a_peripheral = 0; + } else if (devctl & MUSB_DEVCTL_BDEVICE) { musb->xceiv->state = OTG_STATE_B_PERIPHERAL; musb->g.is_a_peripheral = 0; } else { -- cgit v1.2.3-59-g8ed1b