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 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 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 leads to USB devices failing to enumerate when control transfers fail: dwc2 3f980000.usb: Cannot do DMA to address 0x000000003a166a00 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 <stable@xxxxxxxxxxxxxxx> # 4.12 Cc: Robin Murphy <robin.murphy@xxxxxxx> Cc: Sricharan R <sricharan@xxxxxxxxxxxxxx> Cc: Stefan Wahren <stefan.wahren@xxxxxxxx> Reported-by: Hans Verkuil <hverkuil@xxxxxxxxx> Signed-off-by: Johan Hovold <johan@xxxxxxxxxx> --- drivers/base/dma-mapping.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c index b555ff9dd8fc..c6cde7e79599 100644 --- a/drivers/base/dma-mapping.c +++ b/drivers/base/dma-mapping.c @@ -13,6 +13,7 @@ #include <linux/gfp.h> #include <linux/of_device.h> #include <linux/slab.h> +#include <linux/usb.h> #include <linux/vmalloc.h> /* @@ -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->bus == &usb_bus_type) + 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->bus == &usb_bus_type) + return; + of_dma_deconfigure(dev); acpi_dma_deconfigure(dev); } -- 2.13.3