Exynos850 has True Random Number Generator (TRNG) block which is very similar to Exynos5250 for which the driver already exists (exynos-trng.c). There are two differences though: 1. Additional SSS PCLK clock has to be enabled to make TRNG registers accessible. 2. All SSS registers (including TRNG area) are protected with TrustZone and can only be accessed from EL3 monitor. So the corresponding SMC calls have to be used instead to interact with TRNG block. This patch series enables TRNG support on Exynos850 SoC. It was tested on the E850-96 board running Debian rootfs like this: 8<-------------------------------------------------------------->8 # cat /sys/devices/virtual/misc/hw_random/rng_current 12081400.rng # dd if=/dev/hwrng bs=100000 count=1 > /dev/null ... 122KB/s # apt install rng-tools5 # rngtest -c 1000 < /dev/hwrng ... rngtest: starting FIPS tests... rngtest: bits received from input: 20000032 rngtest: FIPS 140-2 successes: 1000 rngtest: FIPS 140-2 failures: 0 rngtest: FIPS 140-2(2001-10-10) Monobit: 0 rngtest: FIPS 140-2(2001-10-10) Poker: 0 rngtest: FIPS 140-2(2001-10-10) Runs: 0 rngtest: FIPS 140-2(2001-10-10) Long run: 0 rngtest: FIPS 140-2(2001-10-10) Continuous run: 0 rngtest: input channel speed: (min=941.855; avg=965.515; max=968.236)Kibits/s rngtest: FIPS tests speed: (min=49.542; avg=52.886; max=53.577)Mibits/s rngtest: Program run time: 20590194 microseconds 8<-------------------------------------------------------------->8 Changes in v2: - Removed the patch for renaming the dt-bindings doc file - Added the patch for using devm_clk_get_enabled() to get the clock - Addressed all review comments for v1 series Sam Protsenko (7): dt-bindings: rng: Add Exynos850 support to exynos-trng hwrng: exynos: Improve coding style hwrng: exynos: Use devm_clk_get_enabled() to get the clock hwrng: exynos: Implement bus clock control hwrng: exynos: Add SMC based TRNG operation hwrng: exynos: Enable Exynos850 support arm64: dts: exynos850: Enable TRNG .../bindings/rng/samsung,exynos5250-trng.yaml | 40 +++- arch/arm64/boot/dts/exynos/exynos850.dtsi | 8 + drivers/char/hw_random/exynos-trng.c | 216 +++++++++++++----- 3 files changed, 206 insertions(+), 58 deletions(-) -- 2.39.2