[PATCH v3 5/5] arm: exynos: Enable TRNG on E850-96 board

[Sam Protsenko]

Enable True Random Number Generator (TRNG) on E850-96 board. To do so:
  1. Enable DM_RNG and RNG_EXYNOS for TARGET_E850_96
  2. Add TRNG node to E850-96 device tree
  3. Enable 'rng' command support for easy TRNG testing

TRNG node is already applied in Linux kernel device tree, but it hasn't
appeared in upstream dts yet. Add it in U-Boot override dtsi file
temporarily; it can be removed once it appears in upstream dts.

Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>
---
Changes in v3:
  - Fixed applying the defconfig changes on U-Boot/master branch

Changes in v2:
  - (none)

 arch/arm/dts/exynos850-e850-96-u-boot.dtsi | 11 +++++++++++
 arch/arm/mach-exynos/Kconfig               |  2 ++
 configs/e850-96_defconfig                  |  1 +
 3 files changed, 14 insertions(+)

diff --git a/arch/arm/dts/exynos850-e850-96-u-boot.dtsi b/arch/arm/dts/exynos850-e850-96-u-boot.dtsi
index 6d7148f7264a..3aa5d8bb10d0 100644
--- a/arch/arm/dts/exynos850-e850-96-u-boot.dtsi
+++ b/arch/arm/dts/exynos850-e850-96-u-boot.dtsi
@@ -3,6 +3,17 @@
  * Copyright (c) 2023 Linaro Ltd.
  */
 
+&soc {
+	/* TODO: Remove this node once it appears in upstream dts */
+	trng: rng at 12081400 {
+		compatible = "samsung,exynos850-trng";
+		reg = <0x12081400 0x100>;
+		clocks = <&cmu_core CLK_GOUT_SSS_ACLK>,
+			 <&cmu_core CLK_GOUT_SSS_PCLK>;
+		clock-names = "secss", "pclk";
+	};
+};
+
 &pmu_system_controller {
 	bootph-all;
 	samsung,uart-debug-1;
diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
index cad8bb044cf0..3fee5a4299b8 100644
--- a/arch/arm/mach-exynos/Kconfig
+++ b/arch/arm/mach-exynos/Kconfig
@@ -250,6 +250,8 @@ config TARGET_E850_96
 	select PINCTRL
 	select PINCTRL_EXYNOS850
 	imply OF_UPSTREAM
+	imply DM_RNG
+	imply RNG_EXYNOS
 
 endchoice
 endif
diff --git a/configs/e850-96_defconfig b/configs/e850-96_defconfig
index 38b9968c1671..2949da24267f 100644
--- a/configs/e850-96_defconfig
+++ b/configs/e850-96_defconfig
@@ -11,6 +11,7 @@ CONFIG_DEFAULT_DEVICE_TREE="exynos/exynos850-e850-96"
 CONFIG_SYS_LOAD_ADDR=0x80000000
 # CONFIG_AUTOBOOT is not set
 # CONFIG_DISPLAY_CPUINFO is not set
+CONFIG_CMD_RNG=y
 # CONFIG_NET is not set
 CONFIG_CLK_EXYNOS850=y
 # CONFIG_MMC is not set
-- 
2.39.2