Hi,

On Fri, Mar 01, 2019 at 07:48:15PM +0200, Georgi Djakov wrote:

On 2/11/19 17:02, Maxime Ripard wrote:

quoted

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 <redacted>
---
 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?

Thanks!
Maxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com