On Thu, Jun 26, 2014 at 04:06:21PM -0500, Andy Gross wrote:

> +	if (xfer->rx_buf) {
> +		rx_dma = dma_map_single(controller->dev, xfer->rx_buf,
> +			xfer->len, DMA_FROM_DEVICE);

It would be better to use the core DMA mapping code rather than open
coding.  This code won't work for vmalloc()ed addresses, or physically
non-contiguous addresses unless there's an IOMMU fixing things up.