path: root/dts/Bindings/arm/sunxi/smp-sram.txt
blob: 082e6a9382d3b315d4c3ad79af7a52b7c494e47e (plain) (tree)

Allwinner SRAM for smp bringup:

Allwinner's A80 SoC uses part of the secure sram for hotplugging of the
primary core (cpu0). Once the core gets powered up it checks if a magic
value is set at a specific location. If it is then the BROM will jump
to the software entry address, instead of executing a standard boot.

Therefore a reserved section sub-node has to be added to the mmio-sram

Note that this is separate from the Allwinner SRAM controller found in
../../sram/sunxi-sram.txt. This SRAM is secure only and not mappable to
any device.

Also there are no "secure-only" properties. The implementation should
check if this SRAM is usable first.

Required sub-node properties:
- compatible : depending on the SoC this should be one of:

The rest of the properties should follow the generic mmio-sram discription
found in ../../misc/sram.txt


	sram_b: sram@20000 {
		/* 256 KiB secure SRAM at 0x20000 */
		compatible = "mmio-sram";
		reg = <0x00020000 0x40000>;
		#address-cells = <1>;
		#size-cells = <1>;
		ranges = <0 0x00020000 0x40000>;

		smp-sram@1000 {
			 * This is checked by BROM to determine if
			 * cpu0 should jump to SMP entry vector
			compatible = "allwinner,sun9i-a80-smp-sram";
			reg = <0x1000 0x8>;