On Mon, Jun 24, 2013 at 6:53 AM, Sekhar Nori <nsekhar@xxxxxx> wrote: > On 6/22/2013 8:23 AM, Joel A Fernandes wrote: >>>>> config TI_EDMA >>>>> tristate "TI EDMA support" >>>>> default m if 'ARCH_DAVINCI || ARCH_OMAP1 || ARCH_OMAP2 >>>>> select DMA_ENGINE >>>>> select DMA_VIRTUAL_CHANNELS >>>> >>>> >>>> MMC depends on EDMA specially on AM33xx there's no PIO mode AFAIK. The >>>> 'm' option will require some initramfs to load the module when needing >>>> to MMC boot, I suggest lets leave it as y. >>>> >>> >>> Ah, right: you still export a filter function from the edma driver >>> and use it in slave drivers: >>> >>> drivers/mmc/host/davinci_mmc.c: dma_request_slave_channel_compat(mask, edma_filter_fn, >>> drivers/mmc/host/davinci_mmc.c: dma_request_slave_channel_compat(mask, edma_filter_fn, >>> drivers/spi/spi-davinci.c: dspi->dma_rx = dma_request_channel(mask, edma_filter_fn, >>> drivers/spi/spi-davinci.c: dspi->dma_tx = dma_request_channel(mask, edma_filter_fn, >>> >>> As long as this is the case, you have to be careful with the dependencies >>> to make sure that davinci_mmc and spi-davinci either depend on TI_EDMA, or >>> edma_filter_fn gets defined to NULL when you are building for a DT-only platform. >> >> Yes sure, right now they are defined as follows in include/linux/edma.h: >> >> #if defined(CONFIG_TI_EDMA) || defined(CONFIG_TI_EDMA_MODULE) >> bool edma_filter_fn(struct dma_chan *, void *); >> #else >> static inline bool edma_filter_fn(struct dma_chan *chan, void *param) >> { >> return false; >> } >> #endif >> >> This also has the side effect of causing DMA requests to fail if >> TI_EDMA is not built, causing frustration for a lot of people some of >> whom don't want to deal with DMA so I think it is OK to build the >> driver in by default as it is (and will be) used by a lot of >> OMAP2PLUS. > > Solution for this is to enable TI_EDMA in relevant defconfigs. Most > folks who would get frustrated by such issues would be using defconfigs > and for those who are building their configuration from scratch this > will be pretty low in their list of worries. Yes, it is not in omap2plus_defconfig either. I will post a patch to add it to the same, and we can ignore the Kconfig defaults and select patches. Thanks, Joel -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html