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authorJoel Stanley <joel@jms.id.au>2018-03-22 06:37:35 +0100
committerJoel Stanley <joel@jms.id.au>2018-04-30 06:51:29 +0200
commit5daa8212c08ecaf4f79b4e9426bb50c193d3370a (patch)
tree02421406ecabed567a0ff383ada77dbbd66fe86f
parentLinux 4.17-rc2 (diff)
downloadlinux-5daa8212c08ecaf4f79b4e9426bb50c193d3370a.tar.xz
linux-5daa8212c08ecaf4f79b4e9426bb50c193d3370a.zip
ARM: dts: aspeed: Describe random number device
There is a random number generator that updates a register in the SCU every second. This is compatible with the timeriomem rng driver in the kernel. From the timeriomem_rng bindings: quality: estimated number of bits of true entropy per 1024 bits read from the rng. Defaults to zero which causes the kernel's default quality to be used instead. Note that the default quality is usually zero which disables using this rng to automatically fill the kernel's entropy pool. As to the recommended value for us to use: Rick Altherr <raltherr@google.com> wrote: > Quality is #bit of entropy per 1000 bits read. 100 is a > conservative value that was suggested by those in the know. Signed-off-by: Joel Stanley <joel@jms.id.au>
-rw-r--r--arch/arm/boot/dts/aspeed-g4.dtsi8
-rw-r--r--arch/arm/boot/dts/aspeed-g5.dtsi7
2 files changed, 15 insertions, 0 deletions
diff --git a/arch/arm/boot/dts/aspeed-g4.dtsi b/arch/arm/boot/dts/aspeed-g4.dtsi
index 518d2bc7c7fc..8d7303ad5273 100644
--- a/arch/arm/boot/dts/aspeed-g4.dtsi
+++ b/arch/arm/boot/dts/aspeed-g4.dtsi
@@ -125,6 +125,14 @@
pinctrl: pinctrl {
compatible = "aspeed,g4-pinctrl";
};
+
+ };
+
+ rng: hwrng@78 {
+ compatible = "timeriomem_rng";
+ reg = <0x78 0x4>;
+ period = <1>;
+ quality = <100>;
};
adc: adc@1e6e9000 {
diff --git a/arch/arm/boot/dts/aspeed-g5.dtsi b/arch/arm/boot/dts/aspeed-g5.dtsi
index f9917717dd08..c4a20d590e47 100644
--- a/arch/arm/boot/dts/aspeed-g5.dtsi
+++ b/arch/arm/boot/dts/aspeed-g5.dtsi
@@ -164,6 +164,13 @@
};
};
+ rng: hwrng@78 {
+ compatible = "timeriomem_rng";
+ reg = <0x78 0x4>;
+ period = <1>;
+ quality = <100>;
+ };
+
gfx: display@1e6e6000 {
compatible = "aspeed,ast2500-gfx", "syscon";
reg = <0x1e6e6000 0x1000>;