[RFC v2 2/2] rng: Provide a RNG based on the RISC-V Zkr ISA extension

[Leo Liang]

On Sun, Oct 29, 2023 at 09:45:33AM +0100, Heinrich Schuchardt wrote:
> The Zkr ISA extension (ratified Nov 2021) introduced the seed CSR. It
> provides an interface to a physical entropy source.
> 
> A RNG driver based on the seed CSR is provided. It depends on
> mseccfg.sseed being set in the SBI firmware.
> 
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> ---
> v2:
> 	Resume after exception if seed CSR cannot be read.
> ---
>  drivers/rng/Kconfig         |   8 +++
>  drivers/rng/Makefile        |   1 +
>  drivers/rng/riscv_zkr_rng.c | 116 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 125 insertions(+)
>  create mode 100644 drivers/rng/riscv_zkr_rng.c

Reviewed-by: Leo Yu-Chi Liang <ycliang at andestech.com>