Re: [PATCH] dmatest: flush and invalidate destination buffer before DMA

["Dan Williams" <dan.j.williams@intel.com>]

On Fri, Jan 9, 2009 at 1:30 AM, Atsushi Nemoto <anemo@mba.ocn.ne.jp> wrote:
> Do you mean something like this?

Yes, exactly.

>
>                dmatest_init_srcbuf(thread->srcbuf, src_off, len);
>                dmatest_init_dstbuf(thread->dstbuf, dst_off, len);
>
>                dma_src = dma_map_single(dev->dev, src + src_off, len,
>                         DMA_TO_DEVICE);
>                dma_dest = dma_map_single(dev->dev, dest_buf, test_buf_size,
>                        DMA_BIDIRECTIONAL);
>                tx = dev->device_prep_dma_memcpy(chan, dma_dest + dst_off,
>                                dma_src, len,
>                                DMA_CTRL_ACK | DMA_COMPL_SKIP_DEST_UNMAP);
>                if (!tx) {
>                        /* error */
>                }
>                tx->callback = NULL;
>                cookie = tx->tx_submit(tx);
>                ...
>                /* wait for completion */
>                ...
>                dma_unmap_single(dev->dev, dma_dest, test_buf_size,
>                        DMA_BIDIRECTIONAL);
>
> It will make dmatest more aggressive, for example, a option for
> testing DMA_PREP_INTERRUPT handling of a lowlevel driver can be added
> easily.
>

Yes, and it will also allow testing of corner cases like dependency
chains and other async_tx api driver-assumptions.

Thanks,
Dan