[PATCH v5 1/4] of: also handle dma-noncoherent in of_dma_is_coherent()

[Rob Herring]

On Wed, Jun 29, 2022 at 4:00 PM Heiko Stuebner <heiko at sntech.de> wrote:
>
> of_dma_is_coherent() currently expects the architecture to be
> non-coherent and some devices being coherent getting marked
> as such with the dma-coherent devicetree property.
>
> For PowerPC CONFIG_OF_DMA_DEFAULT_COHERENT was added which currently
> makes of_dma_is_coherent() always return true but doesn't handle
> the case of the architecture being coherent but some devices not.
>
> So modify the function to also check for dma-noncoherent and
> set a suitable default return value. If CONFIG_OF_DMA_DEFAULT_COHERENT
> is set the value starts with true and finding dma-noncoherent will
> set it to false and without CONFIG_OF_DMA_DEFAULT_COHERENT, the
> behaviour is reversed.
>
> Signed-off-by: Heiko Stuebner <heiko at sntech.de>
> ---
>  drivers/of/address.c | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)

Reviewed-by: Rob Herring <robh at kernel.org>