To allow this device to fill the kernel's entropy pool at boot, setup a default quality for the hwrng found in Cr50. After some testing with rngtest and dieharder it was, in short, discovered that the RNG produces fair quality randomness, giving around 99.93% successes in rngtest FIPS140-2. Notably, though, when testing with dieharder it was noticed that the p-values distribution wasn't uniform in all the cases, so a conservative quality value was chosen. Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx> --- Sorry for the resend, I forgot to include linux-kernel@xxxxxxxxxxxxxxx the first time. drivers/char/tpm/tpm_tis_spi_cr50.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/char/tpm/tpm_tis_spi_cr50.c b/drivers/char/tpm/tpm_tis_spi_cr50.c index ea759af25634..d6195fb58036 100644 --- a/drivers/char/tpm/tpm_tis_spi_cr50.c +++ b/drivers/char/tpm/tpm_tis_spi_cr50.c @@ -264,6 +264,7 @@ int cr50_spi_probe(struct spi_device *spi) phy = &cr50_phy->spi_phy; phy->flow_control = cr50_spi_flow_control; phy->wake_after = jiffies; + phy->priv.rng_quality = 700; init_completion(&phy->ready); cr50_phy->access_delay = CR50_NOIRQ_ACCESS_DELAY; -- 2.33.0
