of: Add OF_DMA_DEFAULT_COHERENT & select it on powerpc
commit dabf6b36b83a18d57e3d4b9d50544ed040d86255 upstream.
There's an OF helper called of_dma_is_coherent(), which checks if a
device has a "dma-coherent" property to see if the device is coherent
for DMA.
But on some platforms devices are coherent by default, and on some
platforms it's not possible to update existing device trees to add the
"dma-coherent" property.
So add a Kconfig symbol to allow arch code to tell
of_dma_is_coherent() that devices are coherent by default, regardless
of the presence of the property.
Select that symbol on powerpc when NOT_COHERENT_CACHE is not set, ie.
when the system has a coherent cache.
Fixes: 92ea637edea3 ("of: introduce of_dma_is_coherent() helper")
Cc: stable@vger.kernel.org # v3.16+
Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index fa8f2aa..f529d3d 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -85,6 +85,7 @@
select BINFMT_ELF
select ARCH_HAS_ELF_RANDOMIZE
select OF
+ select OF_DMA_DEFAULT_COHERENT if !NOT_COHERENT_CACHE
select OF_EARLY_FLATTREE
select OF_RESERVED_MEM
select HAVE_FTRACE_MCOUNT_RECORD