Re: [PATCH V3 0/3] Add support for using external dma in SDHCI

[Faiz Abbas]

Hi Chunyan,

On 04/12/18 12:54 PM, Chunyan Zhang wrote:
> Currently the generic SDHCI code in the Linux kernel supports the SD
> standard DMA integrated into 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 a generic DMA
> controller with SDHCI which in practice means any SDHCI controller that
> doesn't have an integrated DMA controller so we should have this as a
> generic feature.
> 
> There are already a number of controller specific drivers that have dmaengine
> code, and some could use sdhci.c actually, but needed to implement mmc_ops->request()
> in their specific driver for sending command with external dma using dmaengine
> framework, with this patchset, them will take advantage of the generic support.
> TI's omap controller is the case as an example.
> 
> Any comments are very appreciated.
> 

Following your comments, I added dmas in dra7.dtsi as shown in the patch
below.

https://pastebin.ubuntu.com/p/J4F3xWZv5c/

This time the MMC devices enumerate successfully but I see a bunch of

[  108.135736] omap-dma-engine 4a056000.dma-controller: t2_desc[10]
allocation failed

messages when I try to run a short ltp test.

https://pastebin.ubuntu.com/p/WvRSkxBPpv/

Thanks,
Faiz