Re: [PATCH v1] dmaengine: idma64: Use actual device for DMA transfers

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

On Mon, Mar 18, 2019 at 06:39:30PM +0300, Andy Shevchenko wrote:
> Intel IOMMU, when enabled, tries to find the domain of the device,
> assuming it's a PCI one, during DMA operations, such as mapping or
> unmapping. Since we are splitting the actual PCI device to couple of
> children via MFD framework (see drivers/mfd/intel-lpss.c for details),
> the DMA device appears to be a platform one, and thus not an actual one
> that performs DMA. In a such situation IOMMU can't find or allocate
> a proper domain for its operations. As a result, all DMA operations are
> failed.
> 
> In order to fix this, supply parent of the platform device
> to the DMA engine framework and fix filter functions accordingly.
> 
> We may rely on the fact that parent is a real PCI device, because no
> other configuration is present in the wild.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

For the tty/serial/ portion:

Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>