[PATCH v3 0/2] hwrng: Add Arm SMCCC TRNG based driver

From: Andre Przywara
Date: Mon Jul 26 2021 - 13:56:56 EST


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 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

drivers/char/hw_random/Kconfig | 14 +++
drivers/char/hw_random/Makefile | 1 +
drivers/char/hw_random/arm_smccc_trng.c | 134 ++++++++++++++++++++++++
drivers/firmware/smccc/smccc.c | 17 +++
4 files changed, 166 insertions(+)
create mode 100644 drivers/char/hw_random/arm_smccc_trng.c

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2.17.6