Re: [PATCH v4 0/2] hwrng: Add Arm SMCCC TRNG based driver

[Ard Biesheuvel]

On Sat, 31 Jul 2021 at 22:49, Andre Przywara <andre.przywara@xxxxxxx> wrote:
>
> The "Arm True Random Number Generator Firmware Interface"[1] provides
> an SMCCC based interface to a true hardware random number generator.
> So far we are using that in arch_get_random_seed(), but it might be
> useful to expose the entropy through the /dev/hwrng device as well. This
> allows to assess the quality of the implementation, by using "rngtest"
> from the rng-tools package, for example.
>
> Patch 1 creates a platform device, triggered by the previous discovery
> of the SMCCC TRNG service.
> Patch 2 implements a hw_random platform driver, which is instantiated
> through this said platform device.
>
> The driver can be loaded as module, or built into the kernel.
>
> [1] https://developer.arm.com/documentation/den0098/latest/
>
> Changelog v3 ... v4:
> - drop pointless driver loading message
> - drop unneeded init() routine
>
> Changelog v2 ... v3:
> - split platform device and driver
>
> Changelog v1 ... v2:
> - fix building as a module
> - de-register device upon exit
> - mention module name in Kconfig
>
> Andre Przywara (2):
>   firmware: smccc: Register smccc_trng platform device
>   hwrng: Add Arm SMCCC TRNG based driver
>

Reviewed-by: Ard Biesheuvel <ardb@xxxxxxxxxx>


>  drivers/char/hw_random/Kconfig          |  14 +++
>  drivers/char/hw_random/Makefile         |   1 +
>  drivers/char/hw_random/arm_smccc_trng.c | 123 ++++++++++++++++++++++++
>  drivers/firmware/smccc/smccc.c          |  17 ++++
>  4 files changed, 155 insertions(+)
>  create mode 100644 drivers/char/hw_random/arm_smccc_trng.c
>
> --
> 2.17.6
>