From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753415Ab3LNDsm (ORCPT ); Fri, 13 Dec 2013 22:48:42 -0500 Received: from seketeli.net ([91.121.166.71]:48108 "EHLO ms.seketeli.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753228Ab3LNDsk (ORCPT ); Fri, 13 Dec 2013 22:48:40 -0500 From: Apelete Seketeli To: linux-usb@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Felipe Balbi , Lars-Peter Clausen Subject: [PATCH 3/3] usb: musb: fix setting JZ4740 gadget periphal mode on reset Date: Sat, 14 Dec 2013 04:48:38 +0100 Message-Id: <1386992918-1531-4-git-send-email-apelete@seketeli.net> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1386992918-1531-1-git-send-email-apelete@seketeli.net> References: <1386992918-1531-1-git-send-email-apelete@seketeli.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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: hardcode it instead to B-Device. Signed-off-by: Apelete Seketeli --- drivers/usb/musb/musb_gadget.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c index 32fb057..b4bea7a 100644 --- a/drivers/usb/musb/musb_gadget.c +++ b/drivers/usb/musb/musb_gadget.c @@ -2119,6 +2119,14 @@ __acquires(musb->lock) /* Normal reset, as B-Device; * or else after HNP, as A-Device */ +#if defined(CONFIG_USB_MUSB_JZ4740) || defined(CONFIG_USB_MUSB_JZ4740_MODULE) + /* JZ4740 UDC Controller is not OTG compatible and does not + * have DEVCTL register in silicon: 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; @@ -2126,6 +2134,7 @@ __acquires(musb->lock) musb->xceiv->state = OTG_STATE_A_PERIPHERAL; musb->g.is_a_peripheral = 1; } +#endif /* start with default limits on VBUS power draw */ (void) musb_gadget_vbus_draw(&musb->g, 8); -- 1.7.10.4