On 2015/8/3 19:17, Heiko St?bner wrote: > Hi Shawn, > > Am Montag, 3. August 2015, 11:27:19 schrieb Shawn Lin: >> DesignWare MMC Controller can support two types of DMA >> mode: external dma and internal dma. We get a RK312x platform >> integrated dw_mmc and ARM pl330 dma controller. This patch add >> edmac ops to suuport these platforms. I've tested it on RK312x >> platform with edmac mode and RK3288 platform with idmac mode. >> >> Patch is based on next of git://git.linaro.org/people/ulf.hansson/mmc >> >> Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com> >> >> --- >> >> Changes in v2: >> - Fix typo of dev_info msg >> - remove unused dmach from declaration of dw_mci_dma_slave >> >> drivers/mmc/host/Kconfig | 24 +++++- >> drivers/mmc/host/dw_mmc-pltfm.c | 4 + >> drivers/mmc/host/dw_mmc.c | 169 >> ++++++++++++++++++++++++++++++++++++++-- include/linux/mmc/dw_mmc.h | >> 18 ++++- >> 4 files changed, 205 insertions(+), 10 deletions(-) >> >> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig >> index 6a0f9c7..2a66b08 100644 >> --- a/drivers/mmc/host/Kconfig >> +++ b/drivers/mmc/host/Kconfig >> @@ -607,16 +607,36 @@ config MMC_DW >> help >> This selects support for the Synopsys DesignWare Mobile Storage IP >> block, this provides host support for SD and MMC interfaces, in both >> - PIO and external DMA modes. >> + PIO, internal DMA mode and external DMA modes. >> + >> +choice >> + prompt "DesignWare MMC transfer mode" >> + depends on MMC_DW >> + >> +config MMC_DW_PIO >> + bool "Use PIO transfers only" >> + help >> + Use PIO to transfer data between memory and the hardware. >> + PIO is slower than DMA as it requires CPU instructions to >> + move the data. This has been the traditional default for >> + the DW MCI driver. >> >> config MMC_DW_IDMAC >> bool "Internal DMAC interface" >> - depends on MMC_DW >> help >> This selects support for the internal DMAC block within the Synopsys >> Designware Mobile Storage IP block. This disables the external DMA >> interface. >> >> +config MMC_DW_EDMAC >> + bool "External DMAC interface" >> + help >> + This selects support for the external DMAC block outside the Synopsys >> + Designware Mobile Storage IP block. This disables the internal DMA >> + interface. >> + >> +endchoice >> + > more a drive-by comment: > > This should definitly not be a "choice". We're in multiplatform times, where > you can have support for a multitude of socs using dw_mmc in one kernel. And > one might want to use pio, one might want to use the internal dma while > another one might want to use the external dma. > > So which dma to use should definitly be decided at runtime and not at compile- > time. Thanks for comment, Heiko. Definitly it should be decided at runtime. So more DT-bindings' patches should be ACKed as well if we want to remove all the compile-time transfer mode. Hi, Jaehoon Chung Any suggestion? > > Heiko > > > > -- Shawn Lin
