[PATCH v3 2/3] hwrng: starfive - Add TRNG driver for StarFive SoC
JiaJie Ho
jiajie.ho at starfivetech.com
Mon Jan 9 23:45:17 PST 2023
> -----Original Message-----
> From: Herbert Xu <herbert at gondor.apana.org.au>
> Sent: 10 January, 2023 3:41 PM
> To: JiaJie Ho <jiajie.ho at starfivetech.com>
> Cc: Olivia Mackall <olivia at selenic.com>; Rob Herring <robh+dt at kernel.org>;
> Krzysztof Kozlowski <krzysztof.kozlowski+dt at linaro.org>; Emil Renner
> Berthing <kernel at esmil.dk>; Conor Dooley <conor.dooley at microchip.com>;
> linux-crypto at vger.kernel.org; devicetree at vger.kernel.org; linux-
> kernel at vger.kernel.org; linux-riscv at lists.infradead.org
> Subject: Re: [PATCH v3 2/3] hwrng: starfive - Add TRNG driver for StarFive
> SoC
>
> On Tue, Jan 10, 2023 at 12:52:48AM +0800, Jia Jie Ho wrote:
> >
> > +static irqreturn_t starfive_trng_irq(int irq, void *priv) {
> > + u32 status;
> > + struct starfive_trng *trng = (struct starfive_trng *)priv;
> > +
> > + status = readl(trng->base + STARFIVE_ISTAT);
> > + if (status & STARFIVE_ISTAT_RAND_RDY) {
> > + writel(STARFIVE_ISTAT_RAND_RDY, trng->base +
> STARFIVE_ISTAT);
> > + complete(&trng->random_done);
> > + }
> > +
> > + if (status & STARFIVE_ISTAT_SEED_DONE) {
> > + writel(STARFIVE_ISTAT_SEED_DONE, trng->base +
> STARFIVE_ISTAT);
> > + complete(&trng->reseed_done);
> > + }
> > +
> > + if (status & STARFIVE_ISTAT_LFSR_LOCKUP) {
> > + writel(STARFIVE_ISTAT_LFSR_LOCKUP, trng->base +
> STARFIVE_ISTAT);
> > + /* SEU occurred, reseeding required*/
> > + writel(STARFIVE_CTRL_EXEC_RANDRESEED, trng->base +
> STARFIVE_CTRL);
>
> This could occur at the same time as a GENE_RANDNUM write so perhaps
> you should add some locking?
>
I'll add those in the next version.
> > + ret = devm_request_irq(&pdev->dev, irq, starfive_trng_irq, 0, pdev-
> >name,
> > + (void *)trng);
> > + if (ret)
> > + return dev_err_probe(&pdev->dev, irq,
> > + "Failed to register interrupt handler\n");
>
> ...
>
> > + init_completion(&trng->random_done);
> > + init_completion(&trng->reseed_done);
>
> These completion initialisations should be moved above the IRQ registration
> because you should always be prepared to get spurious interrupts.
>
Will update these too.
> Otherwise the patch looks good.
>
Thanks again for reviewing the patch and providing the useful feedbacks.
Best regards,
Jia Jie
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