Hi Geert > > DMAC reads data from source device, and buffered it until transferable > > size for shink device. Because of this behavoir, DMAC is including > > sink, behavior (snip) > > 0 after cleared. > > clearing Grr, thanks. > > +static void rcar_dmac_chcr_de_barrier(struct rcar_dmac_chan *chan) > > +{ > > + u32 chcr; > > + int i; > > unsigned int > > > + > > + /* > > + * Ensure that the setting of the DE bit is actually 0 after > > + * clearing it. > > + */ > > + for (i = 0; i < 1024; i++) { > > + chcr = rcar_dmac_chan_read(chan, RCAR_DMACHCR); > > + if (!(chcr & RCAR_DMACHCR_DE)) > > + return; > > + udelay(1); > > + } > > What's a typical number of loops needed before DE is really cleared? It case by case, but I don't want to use while(1) loop Best regards --- Kuninori Morimoto -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html