[RFC PATCH 2/5] dmaengine: allow sun6i-dma for more SoCs

[Chen-Yu Tsai]

On Thu, Nov 24, 2016 at 5:16 PM, Andre Przywara <andre.przywara at arm.com> wrote:
> Hi,
>
> On 24/11/16 04:16, Chen-Yu Tsai wrote:
>> Hi,
>>
>> On Thu, Nov 24, 2016 at 9:17 AM, Andre Przywara <andre.przywara at arm.com> wrote:
>>> The sun6i DMA driver is used in the Allwinner A64 and H5 SoC, which
>>> have arm64 capable cores. Add the generic sunxi config symbol to allow
>>> the driver to be selected by arm64 Kconfigs, which don't feature
>>> SoC specific MACH_xxxx configs.
>>>
>>> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
>>> ---
>>>  drivers/dma/Kconfig | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
>>> index af63a6b..003c284 100644
>>> --- a/drivers/dma/Kconfig
>>> +++ b/drivers/dma/Kconfig
>>> @@ -157,7 +157,7 @@ config DMA_SUN4I
>>>
>>>  config DMA_SUN6I
>>>         tristate "Allwinner A31 SoCs DMA support"
>>> -       depends on MACH_SUN6I || MACH_SUN8I || COMPILE_TEST
>>> +       depends on MACH_SUN6I || MACH_SUN8I || COMPILE_TEST || ARCH_SUNXI
>>
>> AFAIK ARCH_SUNXI encompasses/supersedes MACH_SUN*I.
>> (And I don't have to add MACH_SUN9I later :) )
>
> Sure, admittedly it was just a quick hack to get things going.
> Actually I don't know why we had a *depend* on those MACH_s before. I
> think technically it does not depend on a certain SoC (having the
> COMPILE_TEST in there hints on that). So what about:

It was really because this DMA engine only comes with the later
SoCs. We have dma-sun4i for the older one. But yes, there's no
reason why you can't build it for the earlier SoC. It just doesn't
get used.

>
>         depends on ARCH_SUNXI || COMPILE_TEST
>
> and maybe:
>
>         default y if MACH_SUN6I || MACH_SUN8I
>
> Though I see that both multi_v7_defconfig and sunxi_defconfig explicitly
> set this, so this wouldn't be needed?

I guess it's just nice to get stuff out of defconfig?
Why not go all the way and just have

        default y if ARCH_SUNXI

ChenYu

>
> Cheers,
> Andre.