On Tue, Dec 20, 2011 at 02:54:04PM +0530, Vinod Koul wrote: > On Tue, 2011-12-13 at 23:48 +0800, Shawn Guo wrote: > > I have been working on -rc recently, and have not noticed the failure > > until I ran next tree today. The mxs-mmc driver is broken on next > > tree because the DMA_NONE was left over from the dma_transfer_direction > > migration for mxs-dma and its client drivers. > > > For DMA transfer, the NONE direction makes no sense? > > In your conetext, what are you trying to achieve? > The mxs-dma controller has a feature to program peripheral registers with given values (mxs-dma PIO mode). This is designed to pipeline the operations. For example, we can put mxs-mmc controller register values into scatter list as one element together with actual data. Triggering the mxs-dma, the dma will program the values into mxs-mmc controller register to set up and enable mxs-mmc, and then dma continue transfer data from/to mxs-mmc. All these get done in one dmaengine_submit(). And DMA_NONE was used to let mxs-dma know this is a PIO operation. -- Regards, Shawn -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
