On 08/15/2014 09:33 PM, Lennart Sorensen wrote: >> On the other hand if you use DMA then it can handle transfers > 64bytes >> in one go and you can start transfers while the FIFO is not completely >> empty. > > You can dma more than the fifo size?
Yes. The UART asserts the DMA line as long as there is room for $TRESHOLD number of bytes. So we never overflow the FIFO. That is why we can't take any DMA channel but only *the* one. >> There is patch in Greg's tty tree already where you are able to >> configure the RX trigger level. We could wire this up once we agree >> which levels we want support. The OMAP supports all levels from 1…63. > > All? or just every 4 (that's what I just read in the DRA7xx docs). All. Take a look at the RX_TRIGGER constant while comparing source vs manual :) Sebastian -- 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/
