On Thu, Aug 27, 2020 at 10:00:48PM -0400, Rich Felker wrote: > On Tue, Jul 14, 2020 at 02:18:55PM +0200, Christoph Hellwig wrote: > > The code handling non-coherent DMA depends on being able to remap code > > as non-cached. But that can't be done without an MMU, so using this > > option on NOMMU builds is broken. > > > > Signed-off-by: Christoph Hellwig <h...@lst.de> > > --- > > arch/sh/Kconfig | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig > > index f8027eee08edae..337eb496c45a0a 100644 > > --- a/arch/sh/Kconfig > > +++ b/arch/sh/Kconfig > > @@ -61,6 +61,7 @@ config SUPERH > > select MAY_HAVE_SPARSE_IRQ > > select MODULES_USE_ELF_RELA > > select NEED_SG_DMA_LENGTH > > + select NO_DMA if !MMU && !DMA_COHERENT > > select NO_GENERIC_PCI_IOPORT_MAP if PCI > > select OLD_SIGACTION > > select OLD_SIGSUSPEND > > @@ -135,7 +136,7 @@ config DMA_COHERENT > > bool > > 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. Rich
