linux-kernel - Re: [PATCH 1/3] hwrng: imx-rngc - use bitfield macros to read fifo level

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Message-ID: <20230511074300.ocfrmynne7e6wdkj@viti.kaiser.cx>
Date:   Thu, 11 May 2023 09:43:00 +0200
From:   Martin Kaiser <martin@...ser.cx>
To:     Herbert Xu <herbert@...dor.apana.org.au>
Cc:     linux-crypto@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] hwrng: imx-rngc - use bitfield macros to read fifo
 level

Thus wrote Herbert Xu (herbert@...dor.apana.org.au):

> On Thu, Apr 27, 2023 at 08:53:55PM +0200, Martin Kaiser wrote:

> > @@ -133,9 +133,7 @@ static int imx_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait)
> >  			break;

> >  		/* how many random numbers are in FIFO? [0-16] */
> > -		level = (status & RNGC_STATUS_FIFO_LEVEL_MASK) >>
> > -			RNGC_STATUS_FIFO_LEVEL_SHIFT;
> > -
> > +		level = FIELD_GET(RNGC_STATUS_FIFO_LEVEL, status);

> Wouldn't it be simpler to just get rid of the shift?

Yes, we're only checking that level > 0, there's no need for the shift.
I'll submit a new version of the patch.

Thanks,
Martin