[PATCH v2] arm64: dts: meson: g12a: Add hwrng node

[Neil Armstrong]

The Amlogic G12A has the hwrng module at the end of an unknown
"EFUSE" bus.

The hwrng is not enabled on the vendor G12A DTs, but is enabled on
next generation SM1 SoC family sharing the exact same memory mapping.

Let's add the "EFUSE" bus and the hwrng node.

This hwrng has been checked with the rng-tools rngtest FIPS tool :
rngtest: starting FIPS tests...
rngtest: bits received from input: 1630240032
rngtest: FIPS 140-2 successes: 81436
rngtest: FIPS 140-2 failures: 76
rngtest: FIPS 140-2(2001-10-10) Monobit: 10
rngtest: FIPS 140-2(2001-10-10) Poker: 6
rngtest: FIPS 140-2(2001-10-10) Runs: 26
rngtest: FIPS 140-2(2001-10-10) Long run: 34
rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
rngtest: input channel speed: (min=3.784; avg=5687.521; max=19073.486)Mibits/s
rngtest: FIPS tests speed: (min=47.684; avg=52.348; max=52.835)Mibits/s
rngtest: Program run time: 30000987 microseconds

Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
---
Changes since v1:
- fixes efuse bus size to 2000
- add @218 suffix to rng node name

 arch/arm64/boot/dts/amlogic/meson-g12a.dtsi | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-g12a.dtsi b/arch/arm64/boot/dts/amlogic/meson-g12a.dtsi
index cbd05e537cd2..881d0f9a2112 100644
--- a/arch/arm64/boot/dts/amlogic/meson-g12a.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-g12a.dtsi
@@ -197,6 +197,19 @@
 				};
 			};
 
+			apb_efuse: bus@30000 {
+				compatible = "simple-bus";
+				reg = <0x0 0x30000 0x0 0x2000>;
+				#address-cells = <2>;
+				#size-cells = <2>;
+				ranges = <0x0 0x0 0x0 0x30000 0x0 0x2000>;
+
+				hwrng: rng@218 {
+					compatible = "amlogic,meson-rng";
+					reg = <0x0 0x218 0x0 0x4>;
+				};
+			};
+
 			periphs: bus@34400 {
 				compatible = "simple-bus";
 				reg = <0x0 0x34400 0x0 0x400>;
-- 
2.21.0