Re: [PATCH] usb: gadget: aspeed: set port_dev dma mask

Christoph Hellwig
2021-03-26T12:06:15Z

On Fri, Mar 26, 2021 at 12:03:03PM +0000, Robin Murphy wrote:
> This might happen to work out, but is far from correct. Just wait until you
> try it on a platform where the USB controller is behind an IOMMU...
>
> It looks like something is more fundamentally wrong here - the device
> passed to DMA API calls must be the actual hardware device performing the
> DMA, which in USB-land I believe means the controller's sysdev.

The shiny new usb_intf_get_dma_device API provides the device to use.