media: dt-bindings: media: Document bindings for the Cedrus VPU driver

This adds a device-tree binding document that specifies the properties
used by the Cedrus VPU driver, as well as examples.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

diff --git a/Documentation/devicetree/bindings/media/cedrus.txt b/Documentation/devicetree/bindings/media/cedrus.txt
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+Device-tree bindings for the VPU found in Allwinner SoCs, referred to as the
+Video Engine (VE) in Allwinner literature.
+
+The VPU can only access the first 256 MiB of DRAM, that are DMA-mapped starting
+from the DRAM base. This requires specific memory allocation and handling.
+
+Required properties:
+- compatible           : must be one of the following compatibles:
+                       - "allwinner,sun4i-a10-video-engine"
+                       - "allwinner,sun5i-a13-video-engine"
+                       - "allwinner,sun7i-a20-video-engine"
+                       - "allwinner,sun8i-a33-video-engine"
+                       - "allwinner,sun8i-h3-video-engine"
+- reg                  : register base and length of VE;
+- clocks               : list of clock specifiers, corresponding to entries in
+                         the clock-names property;
+- clock-names          : should contain "ahb", "mod" and "ram" entries;
+- resets               : phandle for reset;
+- interrupts           : VE interrupt number;
+- allwinner,sram       : SRAM region to use with the VE.
+
+Optional properties:
+- memory-region                : CMA pool to use for buffers allocation instead of the
+                         default CMA pool.
+
+Example:
+
+reserved-memory {
+       #address-cells = <1>;
+       #size-cells = <1>;
+       ranges;
+
+       /* Address must be kept in the lower 256 MiBs of DRAM for VE. */
+       cma_pool: cma@4a000000 {
+               compatible = "shared-dma-pool";
+               size = <0x6000000>;
+               alloc-ranges = <0x4a000000 0x6000000>;
+               reusable;
+               linux,cma-default;
+       };
+};
+
+video-codec@1c0e000 {
+       compatible = "allwinner,sun7i-a20-video-engine";
+       reg = <0x01c0e000 0x1000>;
+
+       clocks = <&ccu CLK_AHB_VE>, <&ccu CLK_VE>,
+                <&ccu CLK_DRAM_VE>;
+       clock-names = "ahb", "mod", "ram";
+
+       resets = <&ccu RST_VE>;
+       interrupts = <GIC_SPI 53 IRQ_TYPE_LEVEL_HIGH>;
+       allwinner,sram = <&ve_sram 1>;
+};