On 29/11/18 11:59 AM, 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(). > > 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 Yes except we really need to reverse if (host->flags & SDHCI_REQ_USE_DMA) { } if (sdhci_needs_reset(host, mrq)) { } so that we do not unmap before killing the dma Perhaps you could send that as a separate patch. > Is there somewhere else I'm missing? Testing ;-)
