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path: root/drivers/char/hw_random/arm_smccc_trng.c
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2023-07-22hwrng: arm-smccc-trng - don't set drvdataMartin Kaiser1-2/+0
Don't set drvdata, there's nobody who reads it. Signed-off-by: Martin Kaiser <martin@kaiser.cx> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-08-19hwrng: arm-smccc-trng - fix NO_ENTROPY handlingJames Cowgill1-2/+2
The SMCCC_RET_TRNG_NO_ENTROPY switch arm is never used because the NO_ENTROPY return value is negative and negative values are handled above the switch by immediately returning. Fix by handling errors using a default arm in the switch. Fixes: 0888d04b47a1 ("hwrng: Add Arm SMCCC TRNG based driver") Signed-off-by: James Cowgill <james.cowgill@blaize.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2021-08-06hwrng: Add Arm SMCCC TRNG based driverAndre Przywara1-0/+123
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. Add a simple platform driver implementing the hw_random interface. The corresponding platform device is created by the SMCCC core code, we just match it here by name and provide a module alias. Since the firmware takes care about serialisation, this can happily coexist with the arch_get_random_seed() bits. [1] https://developer.arm.com/documentation/den0098/latest/ Signed-off-by: Andre Przywara <andre.przywara@arm.com> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Mark Brown <broonie@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>