If the platform driver failed to setup a dma_mask, but the hardware advertises support for DMA, before DMA would be enabled in dwc2, but disabled in the usb core, making all connectivity break. With this commit, the dwc2 driver will emit a warning and fall back to slave mode in this case. Signed-off-by: Matthijs Kooijman <matthijs@xxxxxxxx> --- drivers/staging/dwc2/hcd.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/staging/dwc2/hcd.c b/drivers/staging/dwc2/hcd.c index ac34d4a..c35583f 100644 --- a/drivers/staging/dwc2/hcd.c +++ b/drivers/staging/dwc2/hcd.c @@ -2801,6 +2801,15 @@ int dwc2_hcd_init(struct dwc2_hsotg *hsotg, int irq, /* Validate parameter values */ dwc2_set_parameters(hsotg, params); + /* Check if the bus driver or platform code has setup a dma_mask */ + if (hsotg->core_params->dma_enable > 0 && + hsotg->dev->dma_mask == NULL) { + dev_warn(hsotg->dev, + "dma_mask not set, disabling DMA\n"); + hsotg->core_params->dma_enable = 0; + hsotg->core_params->dma_desc_enable = 0; + } + /* Set device flags indicating whether the HCD supports DMA */ if (hsotg->core_params->dma_enable > 0) { if (dma_set_mask(hsotg->dev, DMA_BIT_MASK(31)) < 0) -- 1.8.0 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html