[PATCH] of: Add OF_DMA_DEFAULT_COHERENT & select it on powerpc

[Rob Herring]

On Sun, 26 Jan 2020 22:52:47 +1100, Michael Ellerman wrote:
> 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 at vger.kernel.org # v3.16+
> Reported-by: Christian Zigotzky <chzigotzky at xenosoft.de>
> Tested-by: Christian Zigotzky <chzigotzky at xenosoft.de>
> Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
> ---
>  arch/powerpc/Kconfig | 1 +
>  drivers/of/Kconfig   | 4 ++++
>  drivers/of/address.c | 6 +++++-
>  3 files changed, 10 insertions(+), 1 deletion(-)
> 

Applied, thanks.

Rob