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. Thanks, Chunyan Chunyan Zhang (3): mmc: sdhci: add support for using external DMA devices mmc: sdhci-omap: Add using external dma dt-bindings: sdhci-omap: Add example for using dmaengine .../devicetree/bindings/mmc/sdhci-omap.txt | 7 ++ drivers/mmc/host/Kconfig | 13 ++ drivers/mmc/host/sdhci-omap.c | 7 ++ drivers/mmc/host/sdhci.c | 137 ++++++++++++++++++++- drivers/mmc/host/sdhci.h | 12 ++ 5 files changed, 175 insertions(+), 1 deletion(-) -- 2.7.4
