On Tuesday 23 September 2014 17:15:19 Jingchang Lu wrote: > @@ -459,20 +480,27 @@ static void fill_tcd_params(struct fsl_edma_engine *edma, > u16 csr = 0; > > /* > - * eDMA hardware SGs require the TCD parameters stored in memory > - * the same endian as the eDMA module so that they can be loaded > - * automatically by the engine > + * eDMA hardware SGs requires the TCDs to be auto loaded > + * in the same endian as the core whenver the eDAM engine's > + * register endian. So we don't swap the value, waitting > + * for fsl_set_tcd_params doing the swap. > */ This makes no sense: how would the eDMA hardware know what endianess the CPU is using to write this data? Have you tried this running on the same hardware with both big-endian and little-endian kernels? Also, you access this as little-endian data unconditionally rather than cpu-endian as the comment suggests, maybe that is what you meant here? > - edma_writel(edma, src, &(tcd->saddr)); > - edma_writel(edma, dst, &(tcd->daddr)); > - edma_writew(edma, attr, &(tcd->attr)); > - edma_writew(edma, EDMA_TCD_SOFF_SOFF(soff), &(tcd->soff)); > - edma_writel(edma, EDMA_TCD_NBYTES_NBYTES(nbytes), &(tcd->nbytes)); > - edma_writel(edma, EDMA_TCD_SLAST_SLAST(slast), &(tcd->slast)); > - edma_writew(edma, EDMA_TCD_CITER_CITER(citer), &(tcd->citer)); > - edma_writew(edma, EDMA_TCD_DOFF_DOFF(doff), &(tcd->doff)); > - edma_writel(edma, EDMA_TCD_DLAST_SGA_DLAST_SGA(dlast_sga), &(tcd->dlast_sga)); > - edma_writew(edma, EDMA_TCD_BITER_BITER(biter), &(tcd->biter)); > + writel(src, &(tcd->saddr)); > + writel(dst, &(tcd->daddr)); > + > + writew(attr, &(tcd->attr)); You seem to have another preexisting bug: The tcd pointer actually does not point to mmio registers here at all, but instead points to memory that has been returned from dma_pool_alloc. It is not valid to use writel() on such memory, that is only meant to work on real MMIO registers. You should use regular assignments to the registers here, e.g. tcd->saddr = cpu_to_le32(src); tcd->daddr = cpu_to_le32(dst); ... Arnd -- 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
