On Fri, 28 Aug 2020 at 06:24, Christoph Hellwig <hch@xxxxxx> wrote: > > On Thu, Aug 27, 2020 at 10:11:53PM -0400, Rich Felker wrote: > > > This change broke SD card support on J2 because MMC_SPI spuriously > > > depends on HAS_DMA. It looks like it can be fixed just by removing > > > that dependency from drivers/mmc/host/Kconfig. > > > > It can't. mmp_spi_probe fails with ENOMEM, probably due to trying to > > do some DMA setup thing that's not going to be needed if the > > underlying SPI device doesn't support/use DMA. > > Adding the linux-mmc and linux-spi lists, as that seems pretty odd. The mmc_spi driver needs modernizations, so I am not surprised to see odd things. My guess is that in ->probe() we check "if (spi->master->dev.parent->dma_mask)" - > and runs dma_map*() operations, which fails and leads to bailing out of ->probe() to return an error code. However, by looking at the code, one get the feeling that the DMA support is somewhat prepared to be made optional. I guess it has never been really tested, as the Kconfig option has "depends on HAS_DMA" - and it's been like that as long as I can remember. Kind regards Uffe
