On Fri, 2015-08-21 at 13:59 +0530, Vinod Koul wrote: > On Thu, Aug 20, 2015 at 10:30:50AM -0700, Sudeep Dutt wrote: > > On Thu, 2015-08-20 at 10:50 +0530, Vinod Koul wrote: > > > On Mon, Jul 27, 2015 at 04:58:17PM -0700, Ashutosh Dixit wrote: > > > > > + /* > > > > + * This is a hack to program status descriptor since > > > > + * DMA engine API doesn't have support for this. > > > > + */ > > > what do you mean by programming status descriptor, what do you need to > > > program? > > > > > > > The MIC X100 DMA engine has a special status descriptor which writes an > > 8 byte immediate data value to a destination address. It is used to > > signal completion of all DMA descriptors prior to the status descriptor. > > The DMA engine API does not allow drivers to pass a 8 byte value. We are > > allowed to pass a source physical address but we cannot determine the > > source value within the DMA driver using that information specifically > > with the IOMMU enabled. We have added this workaround so that we can > > program this special status update descriptor without making any changes > > to the DMA engine API. > I think this is a special case so you should export an API and let client > program using that API. >
Sounds good. We will export a new API from the MIC X100 DMA driver in the next revision of this patch series. Thanks for the review! Sudeep Dutt -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
