Commit 3f0fb4e8 authored by Michal Miroslaw's avatar Michal Miroslaw Committed by Linus Torvalds

Documentation/DMA-API-HOWTO.txt: fix misleading example

See: DMA-API.txt, part Id, DMA_FROM_DEVICE description.
Signed-off-by: default avatarMichal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 91f6cdf8
...@@ -613,13 +613,13 @@ to use the dma_sync_*() interfaces. ...@@ -613,13 +613,13 @@ to use the dma_sync_*() interfaces.
pass_to_upper_layers(cp->rx_buf); pass_to_upper_layers(cp->rx_buf);
make_and_setup_new_rx_buf(cp); make_and_setup_new_rx_buf(cp);
} else { } else {
/* Just sync the buffer and give it back /* CPU should not write to
* to the card. * DMA_FROM_DEVICE-mapped area,
* so dma_sync_single_for_device() is
* not needed here. It would be required
* for DMA_BIDIRECTIONAL mapping if
* the memory was modified.
*/ */
dma_sync_single_for_device(&cp->dev,
cp->rx_dma,
cp->rx_len,
DMA_FROM_DEVICE);
give_rx_buf_to_card(cp); give_rx_buf_to_card(cp);
} }
} }
......
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