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
