Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751917AbdHCNPH (ORCPT ); Thu, 3 Aug 2017 09:15:07 -0400 Received: from mail-lf0-f66.google.com ([209.85.215.66]:38430 "EHLO mail-lf0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751865AbdHCNPD (ORCPT ); Thu, 3 Aug 2017 09:15:03 -0400 From: Johan Hovold To: Christoph Hellwig , Marek Szyprowski , Greg Kroah-Hartman Cc: =?UTF-8?q?Andreas=20F=C3=A4rber?= , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, Johan Hovold , stable , Robin Murphy , Sricharan R , Stefan Wahren Subject: [PATCH v2] dma-mapping: skip USB devices when configuring DMA during probe Date: Thu, 3 Aug 2017 15:14:44 +0200 Message-Id: <20170803131444.4101-1-johan@kernel.org> X-Mailer: git-send-email 2.13.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3169 Lines: 94 USB devices use the DMA mask and offset of the controller, which have already been setup when a device is probed. Note that modifying the DMA mask of a USB device would change the mask for the controller (and all devices on the bus) as the mask is literally shared. Since commit 2bf698671205 ("USB: of: fix root-hub device-tree node handling"), of_dma_configure() would be called also for root hubs, which use the device node of the controller. A separate, long-standing bug that makes of_dma_configure() generate a 30-bit DMA mask from the RPI3's "dma-ranges" would thus set a broken mask also for the controller. This in turn prevents USB devices from enumerating when control transfers fail: dwc2 3f980000.usb: Cannot do DMA to address 0x000000003a166a00 Note that the aforementioned DMA-mask bug was benign for the HCD itself as the dwc2 driver overwrites the mask previously set by of_dma_configure() for the platform device in its probe callback. The mask would only later get corrupted when the root-hub child device was probed. Fix this, and similar future problems, by simply skipping USB devices when dma_configure() is called during probe. Fixes: 09515ef5ddad ("of/acpi: Configure dma operations at probe time for platform/amba/pci bus devices") Cc: stable # 4.12 Cc: Robin Murphy Cc: Sricharan R Cc: Stefan Wahren Reported-by: Hans Verkuil Signed-off-by: Johan Hovold --- v2 - amend commit message and point out that the long-standing 30-bit DMA-mask bug was benign to the dwc2 HCD itself (Robin) - add and use a new dev_is_usb() helper (Robin) drivers/base/dma-mapping.c | 8 ++++++++ include/linux/usb.h | 5 +++++ 2 files changed, 13 insertions(+) diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c index b555ff9dd8fc..604e99e6660a 100644 --- a/drivers/base/dma-mapping.c +++ b/drivers/base/dma-mapping.c @@ -13,6 +13,7 @@ #include #include #include +#include #include /* @@ -345,6 +346,10 @@ int dma_configure(struct device *dev) enum dev_dma_attr attr; int ret = 0; + /* USB devices share the controller's mask. */ + if (dev_is_usb(dev)) + return 0; + if (dev_is_pci(dev)) { bridge = pci_get_host_bridge_device(to_pci_dev(dev)); dma_dev = bridge; @@ -369,6 +374,9 @@ int dma_configure(struct device *dev) void dma_deconfigure(struct device *dev) { + if (dev_is_usb(dev)) + return; + of_dma_deconfigure(dev); acpi_dma_deconfigure(dev); } diff --git a/include/linux/usb.h b/include/linux/usb.h index cb9fbd54386e..f86ad9d8c756 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -1222,6 +1222,11 @@ struct usb_device_driver { extern struct bus_type usb_bus_type; +static inline bool dev_is_usb(struct device *dev) +{ + return dev->bus == &usb_bus_type; +} + /** * struct usb_class_driver - identifies a USB driver that wants to use the USB major number * @name: the usb class device name for this driver. Will show up in sysfs. -- 2.13.3