Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH v2 2/2] hwrng: iproc-rng200 - Add Broadcom IPROC RNG driver | Date | Wed, 25 Feb 2015 20:17:42 +0100 |
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On Wednesday 25 February 2015 10:16:24 Scott Branden wrote: > This adds a driver for random number generator present on Broadcom > IPROC devices. > > Reviewed-by: Ray Jui <rjui@broadcom.com> > Signed-off-by: Scott Branden <sbranden@broadcom.com>
The driver looks reasonable overall, I have just one question about something that sticks out:
> + while ((num_remaining > 0) && time_before(jiffies, idle_endtime)) { ... > + > + /* Are there any random numbers available? */ > + if ((ioread32(rng_base + RNG_FIFO_COUNT_OFFSET) & > + RNG_FIFO_COUNT_RNG_FIFO_COUNT_MASK) > 0) { ... > + } else { > + if (!wait) > + /* Cannot wait, return immediately */ > + return max - num_remaining; > + > + /* Can wait, give others chance to run */ > + cpu_relax(); > + } > + } > +
It looks like you do a busy-loop around cpu_relax here if asked to wait. Is this intentional? I would normally expect either cond_resched() or some msleep() instead.
Arnd
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