On 11/02/2019 15:02, Maxime Ripard wrote:
The MBUS controller drives the MBUS that other devices in the SoC will
use to perform DMA. It also has a register interface that allows to
monitor and control the bandwidth and priorities for masters on that
bus.
Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxx>
---
Documentation/devicetree/bindings/arm/sunxi/sunxi-mbus.txt | 36 +++++++-
1 file changed, 36 insertions(+)
create mode 100644 Documentation/devicetree/bindings/arm/sunxi/sunxi-mbus.txt
diff --git a/Documentation/devicetree/bindings/arm/sunxi/sunxi-mbus.txt b/Documentation/devicetree/bindings/arm/sunxi/sunxi-mbus.txt
new file mode 100644
index 000000000000..e72b7ac9e359
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/sunxi/sunxi-mbus.txt
@@ -0,0 +1,36 @@
+Allwinner Memory Bus (MBUS) controller
+
+The MBUS controller drives the MBUS that other devices in the SoC will
+use to perform DMA. It also has a register interface that allows to
+monitor and control the bandwidth and priorities for masters on that
+bus.
+
+Required properties:
+ - compatible: Must be one of:
+ - allwinner,sun5i-a13-mbus
+ - reg: Offset and length of the register set for the controller
+ - clocks: phandle to the clock driving the controller
+ - dma-ranges: see booting-without-of.txt
Nit: this is a standard property in DTSpec, so it's probably better to
refer to that rather than Linux-specific documentation.
Robin.
+ - #interconnect-cells: Must be one, with the argument being the MBUS
+ port ID
+
+Each device having to perform their DMA through the MBUS must have the
+interconnects and interconnect-names properties set to the MBUS
+controller and with "dma" as the interconnect name.
+
+Example:
+
+mbus: dram-controller@1c01000 {
+ compatible = "allwinner,sun5i-a13-mbus";
+ reg = <0x01c01000 0x1000>;
+ clocks = <&ccu CLK_MBUS>;
+ dma-ranges = <0x00000000 0x40000000 0x20000000>;
+ #interconnect-cells = <1>;
+};
+
+fe0: display-frontend@1e00000 {
+ compatible = "allwinner,sun5i-a13-display-frontend";
+ ...
+ interconnects = <&mbus 19>;
+ interconnect-names = "dma";
+};
