Hi Rouven,
>
> Hello Hadar,
>
> On Sun, 2020-03-22 at 17:31 +0200, Hadar Gat wrote:
> > Introduce low level Arm CryptoCell TRNG HW support.
> >
> > Signed-off-by: Hadar Gat <[email protected]>
> > ---
> > drivers/char/hw_random/Kconfig | 12 +
> > drivers/char/hw_random/Makefile | 1 +
> > drivers/char/hw_random/cctrng.c | 735
> > ++++++++++++++++++++++++++++++++++++++++
> > drivers/char/hw_random/cctrng.h | 69 ++++
> > 4 files changed, 817 insertions(+)
> > create mode 100644 drivers/char/hw_random/cctrng.c create mode
> > 100644 drivers/char/hw_random/cctrng.h
> >
> > [...]
> > +static int cctrng_probe(struct platform_device *pdev) {
> > + struct resource *req_mem_cc_regs = NULL;
> > + struct cctrng_drvdata *drvdata;
> > + struct device *dev = &pdev->dev;
> > + int rc = 0;
> > + u32 val;
> > + int irq;
> > +
> > + drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
> > + if (!drvdata)
> > + return -ENOMEM;
> > +
> > + drvdata->rng.name = devm_kstrdup(dev, dev_name(dev),
> > GFP_KERNEL);
> > + if (!drvdata->rng.name)
> > + return -ENOMEM;
> > +
> > + drvdata->rng.read = cctrng_read;
> > + drvdata->rng.priv = (unsigned long)drvdata;
>
> You are not initializing drvdata->rng.quality to a default value, which results in
> the TRNG not being used by the kernel by default. If its a perfect TRNG this
> should be set to 1024, i.e. 1024 bits of entropy per
> 1024 bits of input.
Thanks for noticing. I'll fix that.
>
> Regards,
> Rouven Czerwinski
Thanks,
Hadar