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

From: Dan Williams
Date: Fri Jan 09 2009 - 19:40:12 EST


On Fri, Jan 9, 2009 at 1:30 AM, Atsushi Nemoto <anemo@xxxxxxxxxxxxx> 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
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