Re: [PATCH v2 1/3] mmc: sdhci: add support for using external DMA devices

[Shawn Lin]

On 2018/11/29 17:59, Chunyan Zhang wrote:
> Hi Adrian,
>
> On Thu, 29 Nov 2018 at 15:36, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> > On 29/11/18 8:22 AM, Chunyan Zhang wrote:
> > > On Tue, 20 Nov 2018 at 21:41, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> > > > On 12/11/18 9:26 AM, Chunyan Zhang wrote:
> > > > > Some standard SD host controllers can support both external dma
> > > > > controllers as well as ADMA/SDMA in which the SD host controller
> > > > > acts as DMA master. TI's omap controller is the case as an example.
> > > > >
> > > > > Currently the generic SDHCI code supports ADMA/SDMA integrated in
> > > > > the host controller but does not have any support for external DMA
> > > > > controllers implemented using dmaengine, meaning that custom code is
> > > > > needed for any systems that use an external DMA controller with SDHCI.
> > > >
> > > > I still think you probably need to reset the DMA if there are transfer
> > > > errors - perhaps you could comment on that.  Also there are some comments below.
> > >
> > > With regard to "transfer error", do you mean if
> > > sdhci_external_dma_setup() failed?
> >
> > No, I mean any error interrupt that can leave the DMA uncompleted.  For
> > SDHCI, resetting the data circuit cleans that up, but presumably something
> > is needed for external DMA?
>
> Yes, it should need a dmaengine_terminate_all().

No, dmaengine_terminate_all is deprecated for quite a long time.
Please use dmaengine_terminate_{async, sync}() instead.

See Documentation/dmaengine/client.txt


> How about adding that at here (I will wrap it up of course):
> https://elixir.bootlin.com/linux/v4.19.5/source/drivers/mmc/host/sdhci.c#L2553
>
> Is there somewhere else I'm missing?
>
> Thanks,
> Chunyan