Messages in this thread | | | Date | Fri, 24 Jul 2009 22:29:19 +0900 (JST) | Subject | Re: [PATCH] dmaengine: at_hdmac: add DMA slave transfers | From | Atsushi Nemoto <> |
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On Fri, 24 Jul 2009 09:35:37 +0200, Nicolas Ferre <nicolas.ferre@atmel.com> wrote: > > Seems straightforward and self contained, applied. Just curious which > > drivers will take advantage of this slave capability? As it stands I > > do not see any in-tree users of at_hdmac beyond dmatest? > > Well, in fact the same as dw_dmac: atmel-mci. Adaptation of other > drivers are coming: probably ac97 and spi interfaces. > > The patches for adaptation of atmel-mci to at_hdmac are coming...
Your atc_chain_complete() calls dma_unmap_xxx unless DMA_COMPL_SKIP_XXX_UNMAP specified. But atmel-mci driver does not set the flag on dma_async_tx_descriptor. I suppose one of them should be fixed.
It is not clear for me how dma driver should handle unmapping on completion of slave DMA. Are there any consensus on it?
I enclosed unmapping code of txx9dmac driver by "if (!slave)" and did not use DMA_COMPL_SKIP_XXX_UNMAP flag in its client driver (txx9aclc ASoC driver). If consensus made on how to handle unmapping on slave DMA, I will follow it.
--- Atsushi Nemoto
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