2009-01-13 15:35:07

by Atsushi Nemoto

Subject: [PATCH] dmatest: Use custom map/unmap for destination buffer

The dmatest driver should use DMA_BIDIRECTIONAL on the destination buffer
to ensure that the poison values are written to RAM and not just written
to cache and discarded.

Signed-off-by: Atsushi Nemoto <[email protected]>
---
drivers/dma/dmatest.c | 35 +++++++++++++++++++++++++++++++----
1 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
index ed9636b..02c171f 100644
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -218,6 +218,10 @@ static int dmatest_func(void *data)
dma_chan_get(chan);

while (!kthread_should_stop()) {
+ struct dma_device *dev = chan->device;
+ struct dma_async_tx_descriptor *tx;
+ dma_addr_t dma_src, dma_dest;
+
total_tests++;

len = dmatest_random() % test_buf_size + 1;
@@ -227,10 +231,30 @@ static int dmatest_func(void *data)
dmatest_init_srcbuf(thread->srcbuf, src_off, len);
dmatest_init_dstbuf(thread->dstbuf, dst_off, len);

- cookie = dma_async_memcpy_buf_to_buf(chan,
- thread->dstbuf + dst_off,
- thread->srcbuf + src_off,
- len);
+ dma_src = dma_map_single(dev->dev, thread->srcbuf + src_off,
+ len, DMA_TO_DEVICE);
+ /* map with DMA_BIDIRECTIONAL to force writeback/invalidate */
+ dma_dest = dma_map_single(dev->dev, thread->dstbuf,
+ 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) {
+ dma_unmap_single(dev->dev, dma_src, len, DMA_TO_DEVICE);
+ dma_unmap_single(dev->dev, dma_dest,
+ test_buf_size, DMA_BIDIRECTIONAL);
+ pr_warning("%s: #%u: prep error with src_off=0x%x "
+ "dst_off=0x%x len=0x%x\n",
+ thread_name, total_tests - 1,
+ src_off, dst_off, len);
+ msleep(100);
+ failed_tests++;
+ continue;
+ }
+ tx->callback = NULL;
+ cookie = tx->tx_submit(tx);
+
if (dma_submit_error(cookie)) {
pr_warning("%s: #%u: submit error %d with src_off=0x%x "
"dst_off=0x%x len=0x%x\n",
@@ -254,6 +278,9 @@ static int dmatest_func(void *data)
failed_tests++;
continue;
}
+ /* Unmap by myself (see DMA_COMPL_SKIP_DEST_UNMAP above) */
+ dma_unmap_single(dev->dev, dma_dest,
+ test_buf_size, DMA_BIDIRECTIONAL);

error_count = 0;

--
1.5.6.3

2009-01-13 15:48:41

by Haavard Skinnemoen

Subject: Re: [PATCH] dmatest: Use custom map/unmap for destination buffer

Atsushi Nemoto wrote:
> The dmatest driver should use DMA_BIDIRECTIONAL on the destination buffer
> to ensure that the poison values are written to RAM and not just written
> to cache and discarded.
>
> Signed-off-by: Atsushi Nemoto <[email protected]>

Acked-by: Haavard Skinnemoen <[email protected]>

2009-01-13 19:20:59

by Dan Williams

Subject: Re: [PATCH] dmatest: Use custom map/unmap for destination buffer

On Tue, Jan 13, 2009 at 8:48 AM, Haavard Skinnemoen
<[email protected]> wrote:
> Atsushi Nemoto wrote:
>> The dmatest driver should use DMA_BIDIRECTIONAL on the destination buffer
>> to ensure that the poison values are written to RAM and not just written
>> to cache and discarded.
>>
>> Signed-off-by: Atsushi Nemoto <[email protected]>
>
> Acked-by: Haavard Skinnemoen <[email protected]>

Applied to async_tx.git/fixes.

Thanks,
Dan

2009-01-14 14:33:14

by Sosnowski, Maciej

Subject: RE: [PATCH] dmatest: Use custom map/unmap for destination buffer

Atsushi Nemoto wrote:
> The dmatest driver should use DMA_BIDIRECTIONAL on the destination
> buffer
> to ensure that the poison values are written to RAM and not just
> written
> to cache and discarded.
>
> Signed-off-by: Atsushi Nemoto <[email protected]>
> ---

Acked-by: Maciej Sosnowski <[email protected]>