[PATCH v3 1/7] dt-bindings: interconnect: Add a dma interconnect name

[Robin Murphy]

On 05/03/2019 15:53, Maxime Ripard wrote:
> Hi,
> 
> On Fri, Mar 01, 2019 at 07:48:15PM +0200, Georgi Djakov wrote:
>> On 2/11/19 17:02, Maxime Ripard wrote:
>>> The current DT bindings assume that the DMA will be performed by the
>>> devices through their parent DT node, and rely on that assumption for the
>>> address translation using dma-ranges.
>>>
>>> However, some SoCs have devices that will perform DMA through another bus,
>>> with separate address translation rules. We therefore need to express that
>>> relationship, through the special interconnect name "dma".
>>>
>>> Signed-off-by: Maxime Ripard <maxime.ripard at bootlin.com>
>>> ---
>>>   Documentation/devicetree/bindings/interconnect/interconnect.txt | 3 +++
>>>   1 file changed, 3 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/interconnect/interconnect.txt b/Documentation/devicetree/bindings/interconnect/interconnect.txt
>>> index 5a3c575b387a..e69fc2d992c3 100644
>>> --- a/Documentation/devicetree/bindings/interconnect/interconnect.txt
>>> +++ b/Documentation/devicetree/bindings/interconnect/interconnect.txt
>>> @@ -51,6 +51,9 @@ interconnect-names : List of interconnect path name strings sorted in the same
>>>   		     interconnect-names to match interconnect paths with interconnect
>>>   		     specifier pairs.
>>>   
>>> +                     Reserved interconnect names:
>>> +                         * dma: Path from the device to the main memory of the system
>>
>> Bikeshed: As it's from the device to the main memory, maybe here we can
>> also denote this my calling the path dma-mem or dma-memory. For other
>> paths, we are trying to mention both the source and the destination and
>> maybe it would be good to be consistent although this is special one.
> 
> I'm not sure I understand what you mean. You'd like two interconnect
> names, one called dma-memory, and one memory-dma?

Hmm, yes, it's not like "dma" describes an actual source or destination 
either :/

Robin.