dt-bindings: Consolidate SRAM bindings from all vendors

SRAM bindings for various SoCs, using the mmio-sram genalloc
API, are spread over different places - per SoC vendor. Since all of
these are quite similar (they depend on mmio-sram) move them to a common
place.

Suggested-by: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Kukjin Kim <kgene@kernel.org>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Rob Herring <robh@kernel.org>

1 files changed, 72 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/sram/sunxi-sram.txt b/Documentation/devicetree/bindings/sram/sunxi-sram.txt
new file mode 100644
index 000000000000..8d5665468fe7
--- /dev/null
+++ b/Documentation/devicetree/bindings/sram/sunxi-sram.txt
@@ -0,0 +1,72 @@
+Allwinnner SoC SRAM controllers
+-----------------------------------------------------
+
+The SRAM controller found on most Allwinner devices is represented by
+a regular node for the SRAM controller itself, with sub-nodes
+reprensenting the SRAM handled by the SRAM controller.
+
+Controller Node
+---------------
+
+Required properties:
+- compatible : "allwinner,sun4i-a10-sram-controller"
+- reg : sram controller register offset + length
+
+SRAM nodes
+----------
+
+Each SRAM is described using the mmio-sram bindings documented in
+Documentation/devicetree/bindings/sram/sram.txt
+
+Each SRAM will have SRAM sections that are going to be handled by the
+SRAM controller as subnodes. These sections are represented following
+once again the representation described in the mmio-sram binding.
+
+The valid sections compatible are:
+    - allwinner,sun4i-a10-sram-a3-a4
+    - allwinner,sun4i-a10-sram-d
+
+Devices using SRAM sections
+---------------------------
+
+Some devices need to request to the SRAM controller to map an SRAM for
+their exclusive use.
+
+The relationship between such a device and an SRAM section is
+expressed through the allwinner,sram property, that will take a
+phandle and an argument.
+
+This valid values for this argument are:
+  - 0: CPU
+  - 1: Device
+
+Example
+-------
+sram-controller@01c00000 {
+	compatible = "allwinner,sun4i-a10-sram-controller";
+	reg = <0x01c00000 0x30>;
+	#address-cells = <1>;
+	#size-cells = <1>;
+	ranges;
+
+	sram_a: sram@00000000 {
+		compatible = "mmio-sram";
+		reg = <0x00000000 0xc000>;
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges = <0 0x00000000 0xc000>;
+
+		emac_sram: sram-section@8000 {
+			compatible = "allwinner,sun4i-a10-sram-a3-a4";
+			reg = <0x8000 0x4000>;
+			status = "disabled";
+		};
+	};
+};
+
+emac: ethernet@01c0b000 {
+	compatible = "allwinner,sun4i-a10-emac";
+	...
+
+	allwinner,sram = <&emac_sram 1>;
+};